Mulholland Drive

Note: I originally intended to this to be a film review of David Lynch's Mulholland drive for Netflix, but it was rejected for being too long so I just posted it here. And, it isn't so much a review as a collection of my thoughts about it. It assumes the reader is familiar with the film as I don't bother discussing cast, crew or a summary of the story line.

I first saw Mulholland Drive in the theater back in 2001. At the time I enjoyed its surreal craziness, but I didn't understand it at all. Thankfully my wife is smarter than I am and she explained it to me at dinner afterwards. Then it clicked with me and I had so see it again so we went back the next weekend with friends. This time around the story made much more sense, but it still seemed that there were a number of extraneous scenes that didn't belong and just seemed like filler.

This past weekend, though, we watched it again on DVD and paused the film frequently to talk ourselves through the story. This time everything fell into place and all those "filler" scenes now made sense and we were able to rationalize how pretty much everything fit nicely into Diane's deteriorating delusions. The more I watched it the more I understood the symbolic elements of the dream sequences.

For me, understanding and really appreciating Mulholland Drive was a multi-step process.

The first time through the film it was difficult to even figure out who's story this was, which is complicated because Betty's name changes to Diane part way through. After that it helped that I was familiar with movies like Jacob's Ladder or An Occurrence at Owl Creek Bridge.

Then it took a bit of time to figure out the two levels of "reality" within the film; which were "real" and which were delusion. And, finally, the film requires a willingness to examine the dream sequences symbolically rather than literally. For me that's the real beauty and genius of Mulholland Drive. The bumbling hitman, the blue box and key, the demented homeless person living behind the diner; these can't be understood by their literal meaning, but only by asking what they mean to Diane. What do they represent to her?

Once I could answer those questions the film was transformed from something chaotic and confusing into something really very beautiful.

Also I have to say that the scene in the Club Silencio is now one of my favorite movie scenes of all time. It is in this scene in which Diane herself realizes what it happening and her moment of clarity combined with the truly haunting singing of Roy Orbison's "Crying" (in Spanish) sends shivers down my spine every time I see it.

It took some patience and effort, but in the end Mulholland Drive became for me a fairly simple plot with a tight narrative and is a very human tale of love and loss; ambition and failure. It doesn't seem like that at first glance, but that's part of the beauty of it. If it was easy to grasp it wouldn't be as meaningful. But, once you do grasp it, the narrative resonates on both an intellectual and very visceral level. It hits you simultaneously deep in your brain and deep in your heart.

More on Jupiter

I couldn't get back to sleep after writing the last entry. I kept wondering if that extra dot I saw when looking at Jupiter really was Neptune. So, I got up and did some more research. It turns out that was I saw was NOT Neptune. They are not yet close enough together to be in the same field of view. Instead, what I was looking at was Mu Capricorni, a 5.0 magnitude star about 90 light years away.

To figure that out I went into my Starry Night software, found Jupiter and backed it up to about 5am this morning. Here's what it gave me after zooming in a bit:
Note that this image is NOT inverted (because Starry Night doesn't give that option, as far as I know). This is pretty much exactly what I saw, so the object above Callisto clearly wasn't Neptune. Too bad.

But, this result begs another question. This morning I clearly saw Io, Europe and Callisto. Where was Ganymede? According to Starry Night I should have seen it there off to one side of Jupiter along with the others. Instead, I saw this:
Io, Europa and Callisto. No Ganymede. This is taken from the Sky & Telescope tool. So, where was Ganymede? This puzzled me until I saw this on the S&T tool:
The times noted are in military time, and also using Greenwich Mean Time, so I have to subtract 5 hours to get my local time. So, early this morning, a few hours before I woke up, Ganymede was visible on one side of Jupiter, then it passed behind Jupiter, then it was visible again on the other side and then it passed into Jupiter's shadow, becoming eclipsed and invisible. At least that's how I interpret the text above. I'm still new at this.

The S&T moon tool accounted for this eclipsing, but the Starry Night software did not. If I had been outside at 4am instead of 5am I would have seen this:
Except, of course, that my image would have been inverted left to right because I'm looking through a refractor.

So, that solves the mysteries of "Was that Neptune?" and "Where's Ganymede?" I guess I'll have to wait a few more weeks until Jupiter and Neptune are visible in the same field of view.

But now, at least, I know where Neptune is. Using Starry Night and zooming out a bit gives you this:
If I get up really early again soon, I can use my wider field eyepieces to find it now. Fortunately the two planets will linger together in the sky for a while because, even though Jupiter moves faster than Neptune, they are going to begin retrograde motion in the coming weeks, increasing the amount of time they will appear near each other.

Ok, curiosity satisfied. Maybe now I can get some more sleep.

sigh... except the kids will be waking up soon. Too bad I have to work tonight. Ugh.

Jupiter (Plus... some new equipment)

Yesterday (Thursday) I had a nice surprise and found that some new equipment that I'd ordered Monday had arrived already.

First off I got to open the new 31mm Baader Hyperion Aspheric eyepiece that I settled on after a few weeks of research. It gives me just under 20x magnification, an exit pupil of 6.2mm and a true field of view of 3.72 degrees (where 1 degree = about the width of 2 full moons). I wanted a wide field eyepiece to get a bit smaller view of the star clusters I've been enjoying and also to double as a finder scope.

Second I opened up the new Green Laser Pointer (GLP). They normally cost $70 to $100 but Astronomics had them on sale for only $30 and I couldn't pass it up. (As of this writing they are still that price, so get 'em while they hot!) Here's a link to a picture showing how the GLP looks when you use it.

The GLP is a very fun and useful tool, especially when you're out viewing with kids or anyone else who is not familiar with the night sky. It is just like a regular laser pointer except that when you point it at the dark night sky you can actually see the laser beam as it shoots off into space. This means you can use it to point at something in space and everyone standing near you can follow the beam of light with their eyes to see what you're pointing at. Did I mention that it is also just fun?

So, I used the new equipment as an excuse to invite my pal John (who doubles as my attorney) over for an evening of stargazing. We looked at Saturn, one or two binaries and the beehive cluster before the durn mosquitoes drove us inside. The 31mm Aspheric did just what I'd hoped it would do. It made it easier to find the beehive and it also gave me a smaller, wider field view of it. Very nice.

But, that's not the point of this post.

This morning my lovely bride had to get up extra early for work (4:30am). This is annoying, but it did give me an excuse to get out of bed to view Jupiter before the sun came up. I've been dying to see Jupiter to see how my 120ST would handle it. After all, seeing Jupiter at a big public star party through a 12" dob last September is the reason I got into astronomy in the first place.

So I got out of bed, went out side and set up my scope kit at about 5am. Jupiter was beautiful. I couldn't see as much detail as I had last year through the big dob, but I could just make out the bands of color and a couple of moons (I couldn't see the big red spot, though). The purple fringing was definitely annoing so I put on the 80mm stop down mask and it made the image much more tolerable.

Off to the right of the image I saw 2 objects which I knew immediately where two of the four Gallilean moons. Off to the right, on the same plain as the right hand objects but much farther away was another object, but I thought it was too far away to be a moon. Almost straight up from that was something else, about the same brightness as the others, but definitely not a moon.

So, after looking for a while I checked out the S&T site and their Jupiter moon tool. After clicking the "inverted" button (to match the view from my refractor's image) this is what came up:
So, I determined that the objects on the right of Jupiter were Io and Europa and one of the left side objects was Callisto. The other object, straight up from Callisto may have been some random star, but I read in a magazine yesterday that Jupiter and Neptune are very close to each other right now. In fact, they may be found in the same field of view (they come closest together by mid-July, if memory serves).

So, the other object may have been Neptune, but I can't say for sure just yet.

I was a bit disappointed that my view of Jupiter wasn't as detailed as what I saw last Fall, but I expected that. I knew that, with the 120ST I was sacrificing planetary detail for portability, but it still made me yearn for more detail.

On the plus side, the 120ST was perfect for getting up early and setting it up quickly in the backyard. I can bring out the scope, tripod and all my accessories out back in one trip and the whole thing takes less than a minute to assemble with no cool-down time.

That part was perfect and I continue to be very pleased with my scope choice. Next year or the year after that I'll start thinking about something bigger to get me both more planetary detail and a wider variety of DSOs. Perhaps a 10" of 12" dob. We'll see. I want a new focuser for the current scope first, and I've already spent more than enough money on telescopery this year as it is.

Castor, Izar, More Saturn

I was out tonight for another nice hour or so of stargazing. I spent some time looking for M67 at the bottom of Cancer, but couldn't find it. So, I then picked my usual starter and spent some time looking at Saturn. I thought I saw another moon again, but only one this time, just to the left of the (inverted) rings. After checking out the Sky and Telescope Saturn Moon tool I determined that it was probably Rhea. I may have been imagining it as I saw it best with averted gaze, but I'm pretty sure it was there.

The other day I read that, as far as multiple star systems go, some are more difficult than others to "split" and a good test of your scope's abilities is the binary star Izar (aka Epsilon Boötis) in the constellation Bootes, which is fairly high high in the sky during the spring. So, after consulting my S&T star chart and figuring out which star that was I gave it a try. I was very pleased to see that I could make out both stars in the Izar system. One of them was definitely bigger and brighter than the other, and the bigger one really outshone the dimmer one. It was much harder to pick out than other binaries I've seen, but it was definitely visible at 140x.

This picture of Izar came from this site. There is some good information there in Izar as well.

I wanted to compare Izar to something reputed to be a bit easier to I pointed the scope at Castor, which is one of the two main stars at the head of Gemini. Castor was much easier to split than Izar. The interesting thing about Castor is that it isn't just a binary system. In fact it is a solar system made up of 3 pairs of binaries, making 6 stars altogether in one system. My scope could only make out 2 stars, though, at 140x.

That's about it, nothing too exciting. I'm still pleased about Izar, though. The 120ST is noted to have some variability in quality. The objective lens is not collimatable, so you're pretty much stuck with what you have. The fact that I could split Izar makes me feel pretty good about the particular scope I have.

Saturn, Beehive Cluster and Algieba

Last night was a beautiful night for stargazing. My wife and I and our two kids gathered in the backyard for a while to find some new things in the sky. This also confirmed that our backyard is superior to the local park because of the lack of tennis court flood lights. Still, the streetlight out front is a bit annoying and I try to set up the scope out of its line of sight.

There are also many large trees in the area, which limit our view of the horizon, but a fairly large chunk of the southern sky is visible stretching from west to east.

The most prominent constellation visible to us right now is Leo. We can still see the heads of Gemini (Pollux and Castor) off to the west as they hang above the no longer visible Orion as well. This meant that our first target (like usual lately) was Saturn, which is cruising through Leo this year and next before it migrates on to Cancer after that.

Saturn was really beautiful, both at 50x and about 140x. The city lights were bright enough that I didn't even need my my stop down mask, which is about the only good thing about the city lights. Now that I've been viewing Saturn for a while, I think I'm getting a bit better at picking out some heretofore unnoticed details. The planet itself is still a bit plain, and the rings are getting closer to edge on, but I did think I saw a couple of moons last night. I saw one of them just above and to the right of the planet itself, and another one above and to the right of the rings. (Given that the image was inverted left to right in my eyepiece.)

Sky and Telescope has an excellent moon tool for Saturn which allows you to enter a date and time and it shows you were each of the moons is when you look at it. It also allows you to invert the image if necessary. Based on it I think the two moons I saw were Titan and Enceladus, although the latter may have been Dione instead.

Next up I set out to find M44, the Beehive Cluster. I had tried to find this one a couple of times but wasn't successful until last night. M44 is in Cancer and is about midway between Gemini and Leo. I knew it was just up and to the right of the middle star in Cancer (Asellus Australis) but before last night I was confused and was looking at the star Procyon instead. (woops!).

So, last night I was able to correctly determine where Cancer was, even though I could only barely see any of its stars with the naked eye. Once I found Asellus Australis finding M44 was easy. It REALLY stood out. The sky all around M44 was pretty devoid of anything interesting, but I was slowly swinging the scope around and, pow, all of a sudden dozens and dozens of stars were visible at 50x using the Ethos. It was very beautiful and took up the entire field of view in the eyepiece. I really need a lower power, wider field eyepiece to really appreciate clusters like this a bit more.

Finally last night I remembered that one of the stars in Leo was a binary system. Algieba, which is one of the central stars in Leo's sickle (2 stars above Regulus, which is at the base of the sickle.)

I had tried to view this binary once before (late on a winter night) but it didn't work out (either due to my inexperience or impatience brought about by the cold). Last night, though, at 140x I was able to clearly resolve the binary pair. Algieba (also known as Gamma Leonis) is about 100 light years away and each of the pair is about double the mass of the sun. I found this picture of Algieba at this site. The view I saw of it looked just like that, although reversed.

This was encouraging because I haven't been sure how well the 120ST would do on binary stars.

All in all it was a good evening of star gazing.

Orion 120ST Telescope Kit

Slowly but surely my telescope kit is taking shape. Last night we walked to a local park to do some star gazing and took the whole thing along in a wagon. Here's what it looks like all packed up.

I bought the case a month or so ago. It was designed for Orion's 110ED scope, but it turns out that my 120ST fits in it quite nicely.
Here's a closeup of the case innards. It has slots for the diagonal, two 2" eyepieces and three 1.25" eyepieces.
And here's what it looks like fully assembled.
The wooden legs are also fairly new. It is an Oberwerk surveyor tripod that I found on sale for 50% off. The legs are longer and more stable than the stock aluminum legs that come with the Voyager mount. I played around with the height for a while before settling on where it is. I raised the legs about 4 inches which allows me to see almost the whole sky from a seated position. Objects too near the horizon still require a standing position, but for the most part I can sit leisurely while stargazing.

The only drawback is that I have to squat down close to the ground in order to find objects with the EZFinder.

There are only a couple of things left to get to complete my portable telescope kit. First, I need a wide field eyepiece. The Ethos lest me see 2.17 degrees of sky at 46X. I'm thinking about a 23mm Axiom which would give me 3.14 degrees at 26x. Alternately, I'm considering jumping all the way to a 31mm or 36mm Hyperion Aspheric, which would broaden the field of view to 3.72 or 4.32 degrees respectively. (A degree is about the width of 2 full moons).

Also, I still want a new focuser. I'm seriously considering getting a Moonlite, but they are a bit pricey so it will involve saving up for it. We'll see. The stock focuser is really annoying, though and does need to be improved somehow.

Anyway, the park last night was a bit disappointing. We set up the scope near second base on one of the local ball fields. This gave us a nice wide swath of sky to view and we got to look at Saturn again. However, there were people playing tennis nearby and the court flood lights were so bright I could read by them a couple of hundred yards away. Very annoying. It turns out that my backyard it a better vewing spot due to the lack of gigantic stadium sized flood lights.

Oh well. We're starting to plan our summer vacations which will be at various dark sky spots around northern Michigan and away from big city lights. I can't wait to see some really wide field views of the summer Milky Way from a very dark site. I'm getting very excited about it.

Saturn

Most of the objects I've been looking at in the night skies are star clusters or nebulae. This hasn't really interested my son Simon very much.

Tonight though, we went out looking at Saturn and the 120ST proved itself on the ringed planet very nicely. First we checked it out at 46x with the 13mm Ethos and then tried again at about 140x with my 4.3mm Antares eyepiece. Both images were very sharp, although focusing at 140x was tough.

Mostly I was pleased to try out the 80mm stop down mask I had built and was very pleased that I saw no color fringing at all with the mask on. It is likely that I would see more color if the sky was darker. I think the light pollution actually helps keep the color down because the object is not as relatively bright as it would be otherwise.

I was a bit disappointed that I couldn't see any planetary detail, though. It was just a white disc with the rings at a very sharp angle. Simon thought it rocked, though. He was jumping up and down. He loves the planets so much that they have actually been elevated to the status of "imaginary friend" (he is 7 years old) and he holds them very dear. It was quite something for him to see the real, live Saturn in the sky with his own eyes.

So, I'm pleased so far with how the 120ST is working on the planets. I'm toying with the idea (some day, not soon) of getting a different sort of telescope just for the planets, but I'm not sure what that one would be yet. Something to think about...

If you're curious, here is a YouTube video that shows that Saturn looks like through a small telescope. The only difference between this video and what I saw tonight is that the image in my scope was totally white, with no yellow / orange tinting. Oh, and the angle of the rings was much sharper as well, and nearly edge on. They will, in fact, be seen edge on from the Earth in early September of this year, before gradually coming to a maximum angle about 18 years from now. (I think it will take 18 years. I pulled that number from memory but will have to verify it to make sure.)

Ghost Stories

The weather has been cold and wet a lot over the past month. I have gotten outside a bit to look at the moon and find one or two more new star clusters, but mostly I've been spending my hobby time playing boardgames.

I've gotten a number of new games lately, topping my game collection over the 100 game count, which is kind of fun. The best new game I've gotten lately is called Ghost Stories. It is one of several cooperative games released in 2008 in which the players team up against the game mechanics rather than against each other. It's a nice change of pace.

In Ghost Stories each player controls a Taoist warrior protecting a Chinese village from an onslaught of mythical Chinese ghosts. It is a bit reminiscent of the 1980's Kurt Russel film "Big Trouble in Little China" and many other silly and similar movies.

In the game a new ghost arrives during each players turn and threatens to "haunt" the 9 village tiles in the center of the board. Once 4 tiles are haunted the players lose. If the players are able to exercise all the ghosts and survive to defeat the big boss ghost at the end of the game, then the players win. Along the way each player is given a special unique power to aid them and each of the 9 village tiles also provides the players with a special unique power if a player moves onto that tile that turn.

There are 2 main characteristics that make Ghost Stories a lot of fun. First, it is very frenetic. The ghosts just keep coming and coming and coming. Each and every turn brings a new sense of panic as the situation threatens to run out of control. Second, the game is very, very hard. I've played about 7 games so far (3 with friends and 4 alone) and I've only won one of my solo games.

The reason that the intense difficulty level makes the game more fun is that it requires a large degree of cooperation among the players. While you play the game it constantly feels like a puzzle that must be solved, but that cannot be solved alone. All four players must act in perfect harmony with very careful planning to see the game through to the end.

All cooperative games require teamwork, but I've never played one that required more teamwork and more group cohesion than Ghost Stories. It's also just a whole lotta fun. I can't wait to play it again!

If you've read this far and are still interested, click here for an interesting video review of the game. (Note: the reviewer has gotten a few of the rules wrong, but it is very informative just the same.)

Another video review can be found here.

Sky Log 2

Last night I braved the cold for two 30 minute sessions at 8pm and again at 1opm so that I could get a good look at Gemini and Leo respectively.

In Gemini I found the M35 star cluster near the feet of the twins. It is about 2,800 light years away and made up of stars that are about 150 million years old. It isn't quite as pretty as M41 (in Canis Major) that I found the last time it was clear out. It was very high in the sky which placed my eyepiece very low to the ground, requiring me to sit or kneel in order to view it comfortably. This wasn't the first time I was discomforted by viewing at the zenith. After a bit of research the last few days I ordered a set of wooden tripod legs which should add stability and add 10"-12" of height. Hopefully this will enable me to sit more comfortably in a chair while viewing.

At 10pm I went back out to try to find Ceres. Ceres is a spherical asteroid in the belt between Mars and Jupiter. Tomorrow night (2/25/09) it will be closer to the Earth than it will be again for several hundred years. I have read that you can see it in a small telescope so I've been anxious to try. I found a star chart from Sky and Telesope's website showing me where it would be on different days. I tried for about 1/2 hour to find it. Annoyingly, I can't say for sure if I saw it or not. I panned around the sky along Leo's back about where I thought it would be and I saw a lot of things that "might" have been it, but I lack the experience to know for sure.

When I tired of that I tried to see some of the galaxies that are grouped together near Leo's haunches, but I couldn't make out anything at all there. Between the city lights and the smallish size of my scope, I don't think I'll see many galaxies from my backyard.

I can't wait to go camping this summer! We're planning to get away to a campground about 100 miles west of us over Memorial Day weekend this year (also our anniversary). Hopefully dark skies will help considerably. Of course, warm weather will also help considerably. I think this hobby will be a lot more fun when the temperatures are above freezing at night!

Sky Log 1

Last night the sky finally cleared up and I managed to spend about an hour in the cold trying to find new DSOs.

I thought I should use this space to begin recording the things I'm viewing and describe what they are and how I found them. This is for my own benefit, primarily, as writing it down helps to
solidify it in my memory.

Note: most of the facts below are summarized either from Wikipedia or from the excellent book Turn Left at Orion by Guy Consolmagno and Dan M. Davis. The images are pulled also from Wikipedia. In general, the pictures always look much cooler than the objects do in real life.

The Moon
There's not much to say about the moon. It was the first thing I pointed my telescope at. It waxing and near full the week I first got outside to view the sky so it drowned out everything else and dominated the sky.


M45, The Pleiades
I've always loved the Pleiades. I've known how to find it for as long as I can remember. My dad showed it to me when I was a boy and, next to Orion, it has been one of my favorite night sky objects. Although it is known as the "7 sisters" I've only ever been able to see 6 stars in the cluster without the telescope. With the telescope, at 46x it was just a bit larger than my field of view and revealed a lot more than just six stars. M45 is an open cluster of young stars. It is about 400 light years away from us and about 8 light years across. They are young stars, only about 50 million years old. In all there are about 200 stars in the cluster. To find the Pleiades, first locate Orion. Up and to the right of Orion is the familiar "V" shape of Taurus. Up and to the right of Taurus is a small, "dipper" shaped cluster of stars which is M45. It looks like it ought to be the Little Dipper, but it isn't. This picture from Wikipedia show you pretty much what you see in a telescope, except that I couldn't see any of that blue fuzziness around the stars. Apparently that is only visible with much larger scopes than mine.

M42, The Orion Nebula
Back in college I took an intro to astronomy course. In it I learned to locate the Orion nebula, but I've never seen it before in the telescope. It is almost straight down from the lower left star in Orion's belt. Even in light polluted skies you can see a bit of fuzziness there. This NASA picture shows the nebula in visible light, but it doesn't look anything like that in my scope. All I saw was a patch of gray. But, I live in a severely light polluted area. I can't wait to see it from a darker site. M42 is a huge area where stars are being born. The gasses are being lit up by the newly formed stars. They're so cute when they're young!


Saturn
I had to use the software "Starry Night" to know where to find Saturn last week. At 140x it was kind of a smeary mess in my scope, but I could see the rings, which are almost edge on this year (and will disappear completely for a time starting in September, 2009). I seriously need a better focuser and more experience. Next time I'll try using my new stop down mask also.

Sigma Orionis
This was the first multiple star system I observed with my telescope. It is, in fact, a 5 star system, but only 4 of the stars are visible in a large telescope. In my scope I could only see 3 of the stars. It is just below and to the right of the star Alnitak, which is the lower left star in Orion's belt. My scope really isn't built for splitting binaries, but I did enjoy trying it out on this one. I forget if I saw it at 46x or at 140x.


The Trapezium
Deep inside the Orion Nebula is a small cluster of young stars which are illuminating the nebula itself. This picture gives an idea of what it looks like, but again, the colors are not really visible. When I observed it last night at 140x I could see 4 stars, but there are apparently several more than can be seen under darker skies with better telescopes. The Orion Nebula and The Trapezium are about 1,500 light years away from us. Here is a bit more information about The Trapezium.


M41
If you follow Orion's belt down and to the left you come to the brightest star in the sky, Sirius, in the constellation Canis Major. Almost straight south of Sirius is M41, which is a discrete cluster of about 100 stars about 20 light years in diameter and about 2,500 light years away from us. This was an exiting find for me because this was the first thing I found in my telescope that I wasn't already able to find. I had to search it out and "discover" it. In my scope it was most readily found by lining Sirius up about 1/2 way between the center of the view and the right side edge and slowly lowering the scope. I'm very glad I got a tripod with slow motion controls. It would be impossible to make this maneuver without them.

As I was slowing moving downward from Sirius I could see many faint stars in the field of view and I couldn't tell if I was seeing M42 or not. I kept thinking "is that a star cluster?" But, then M41 came into view and, pow, it was unmistakable. In an area of sparse stars it really stood out as a round, spherical looking structure. Very cool.

Next time I go out I want to have a very short list of things to look for, maybe one or two objects, aside from the things I already know where to find. I can't wait for warmer weather so I can spend more time outside, and so that the kids won't mind coming out with me. I'm fantasizing about picnic dinners in the backyard while we all talk, play and stargaze.

Preparing for clear skies

It's been very cloudy for about a week so I haven't been able to get out and see the sky much lately.

However, I have made a list of things in the February evening skies to look for once the clouds blow over.

Ceres
Ceres is one of our new dwarf planets. It is a moon sized, spherical asteroid in the belt between Mars and Jupiter. Around 2/25/09 it will come as close to Earth as it will be for several hundred years. It is apparently visible just above the constellation Leo this month.

M36, M37, M38
These are three open star clusters in the constellation Auriga which are not far from each other.

M1
M1 is a super nova remnant. It was so bright in the year 1054 that it could be seen in daylight for several weeks. It is between the constellations Taurus and Auriga, specifically between the stars Zeta Tauri and El Nath.

Sigma Orionis
This is a multiple star system just below the lower, left star in Orion's Belt (Alnitak). Technically it is a 4 star system, but only 3 stars are typically visible. I actually checked this one off my list the other night and could only see 3 stars. It was pretty cool, though.

NGC2392
This is a planetary nebula below and to the right of the star Pollux in the constellation Gemini.

M35 & NGC2158
M35 is an open star cluster to the right of the "feet" of the twins in Gemini. NGC2158 is a tighter cluster near M35 and can apparently be seen in the same field of vew.

M41
A star cluster in Canis Major, below Sirius.

NGC884 / NGC869
These are the "double cluster" in Perseus. They are young stars, only a few million years old and are racing towards earth at about 21k/second. Egads, we're all doomed!

Rigel, Alnitak, Castor
These are all multiple star systems. My telescope really isn't builtfor splitting binaries, but it can't hurt to try.

So that's my short list. I just wanted to make sure I have a plan of things to look for if the skies clear up. It's cold enough outside at night that I may not feel like staying out very long. Gotta make the most of that short time in the cold.

Useful Magnification & Exit Pupils

Every time I think I'm starting to understand the basics of this hobby I learn something new. Last night one of the fellows on the CN forums pointed me over two an article explaining the concept of "Exit Pupils" and from there I also read up on the idea of "Useful Magnification". These are two different methods of choosing eyepieces. I wish I'd fully understood these before I'd bought my first eyepieces. I'm not sure if I'd have made different choices, but I would have had a better feel for "why" I chose specific eyepieces. I am considering returning the expensive Ethos which would allow me to purchase a different eyepiece plus a new focuser, but I'm not sure yet.

Highest Useful Magnification
Basically, the more magnifying power you apply, the bigger something looks, but that object also decreases in brightness at the same time. So, bright objects like planets can take great magnification, but dim objects like nebula and galaxies will become invisible if you apply too much magnification and are better viewed under low power. (This part I knew already). It turns out that there is a recommended magnification for each type of viewing. It goes like this:

Highest magnification per inch of telescope aperture:

• 5-8x power for galaxies and large nebula
• 12-15 power for globular clusters and small nebula
• 25-30 power for binary stars and planets (actually, a long focal ration scope could take up to 50x magnification for this, but my scope, being a short tube, probably can't go much above 30x reliably.)

Since my Orion 120ST has 120mm of aperture (4.73 inches) this means that for galaxies and large nebula I should use an eyepiece that will get me between 24x (or less) and 38x magnifying power. For viewing globular clusters and small nebula I should go for 57x and 71x and for binary stars and planetary viewing I should go for 118x to 142x power. In all cases less magnification will work, and will result in smaller, but brighter images.

To determine the specific focal length of the eyepiece needed for the above requirements, you divide eyepiece focal length into the telescopes focal length. So, because the Orion 120ST has a focal length of 600mm, these sizes of eyepieces become apparent:

• Galaxies and Lg Nebula: 25mm to 16mm focal length
• Globular Clusters & Small Nebula: 11mm to 8mm focal length
• Binary Stars and Planets: 4mm to 5mm focal length

Before I bought my new scope I had a cheap 25mm Kelner that I scavenged off an old kid's scope. It isn't great quality, but it works well enough for my untrained eyes. And, it's the right size for the first category above.

And, the next eyepiece I bought was a 4.3mm W70 Antares, which is right in the range for the 3rd category.

Finally, the 13mm Ethos. This one isn't quite in either the 1st or the 2nd category but straddles them both. I'm not sure what to make of this. These are the two categories I'm most interested in, and why I picked this model telescope in the first place (along with its portability). If I interpret this correctly, I think it means that the Ethos is well positioned to provide a good view of the 2nd category, globular clusters and small nebula, but is probably too high a magnification to pick up the galaxies and large nebula. Since I've been learning how to use the Ethos better, I may be happy keeping it, in spite of its high price. Then, unless I decide I'm happy keeping the 25mm Kelner, I will likely need at least one more higher quality eyepiece in the 16mm to 25mm (or bigger) range.

Exit Pupils
Using the idea of exit pupil size is a second way to choose eyepieces. Basically, every eyepiece has a specific diameter of light emitted from it based on the relationship between the size of the eyepiece and the focal ratio of your telescope. It works like this:

Exit Pupil (mm) = eyepiece focal length / focal ratio of telescope

So, for example, my cool new 13mm Ethos eyepiece combined with my f/5 telescope has an exit pupil of 2.6mm. As I understand it, the human eye never has a pupil size of more than about 7-8mm so anything larger than that is wasted. And, the pupil of your eye shrinks as you age down to about 5mm in your 50s or 60s.

And, just as with the "highest useful magnification" method, there is a recommended exit pupil size for each type of astronomical viewing you might want to do. Here's a quote from the astronomics guide I linked to up at the top of this post:

"The brightness of extended objects (galaxies and nebulas) is proportional to the square of the exit pupil. Therefore, a low power 4mm exit pupil (42 = 16) is four times as bright on galaxies and nebulas as a medium power 2mm exit pupil (22 = 4). To put it another way, twice the power results in one-fourth the brightness on the faint fuzzies outside our solar system."

Basically, for different kinds of deep space objects (DSOs) you want eyepieces with different exit pupil diameters. This link here provides a handy table which I used to generate one of the tables below.

Results: (Note: only valid for a 120mm f/5 telescope)

Using the Highest Magnification method of choosing eyepieces, I generated this table:

And using the Exit Pupil method I generated this table:
The reason for this exercise is to a) determine what sorts of eyepieces I'll need for my chosen purposes and b) figure out if my 13mm Ethos is worth keeping.

My goals with the 120ST are to primarily view deep space objects like star clusters, nebula and other galaxies. Given that, it appears that I would want 2-3 different eyepieces. The first table suggests one eyepiece with a focal length of 16-25+mm for galaxies and large nebula and a second eyepiece with a focal length of 8-11mm for globular clusters and small nebula.

For similar goals the second table suggests 3 eyepieces: 20-35mm for widefield, large deep space objects; 10-20mm for general deepspace viewing and 5-10mm for compact deepsky objects.

The two methods give results that are very similar, though not identical. But, they do both suggest that my 13mm Ethos, with a 2.6mm exit pupil and 46x magnification, is good for general deepsky viewing of most DSOs, but it may be too high a magnification and too small an exit pupil for many galaxies and large nebula. For that purpose I may want to consider a larger eyepiece with a 4-7mm exit pupil and a focal length around 25mm or so. I do still have the 1.25" 25mm Kelner I scavenged, and I can use it for that, but I'll likely want to consider something of higher quality. I've been eyeing a 27mm Televue Panoptic eyepiece for that purpose.

Since I do want to look at the planets or split binary stars occasionally, the results also suggest that my 4.7mm Antares eyepiece is a good one for that as well.

Basically I think I can be happy with my 2 main eyepieces at high and mid power, but that I may want a 3rd eyepiece for widefield DSO use. At some point I may think about something around 8mm. We'll see.

I still think I went a bit overboard buying the 13mm Ethos. If I were starting over again I might not have bought that one, but now that I have I'm finding it difficult to give it up. Its widefield views really are impressive.

So, I might want one more eyepiece, maybe two, and a new focuser. I hate how sticky the stock focuser is.

More thoughts on the 120ST

I got a lot of great feedback on my CN post reprinted below. Here is my followup which will also be simul-posted on the CN forums.

Thank you all for your responses and advice. Even (especially) the constructive criticism is appreciated. I do feel a bit silly for spending so much on the eyepiece (2x what the OTA costs!)

I’ve spent some more time looking at the moon through the Ethos and I’ve been more and more troubled by, well, not the view, but the awkward viewing through the eyepiece. The view is stunning, but the Ethos seemed very picky about head/eye position and I had to move my head in and out and back and forth to get the good image. I spend much of the day yesterday thinking that I should return the Ethos and either get several less pricey eyepieces or maybe a 12T4 (or a 17T4) plus a new focuser.

My goal with the premium eyepiece was two-fold. First I wanted the best wide field image I could get to compliment the 120ST’s natural wide field, deep space views. Second, I’m guessing that I will end up buying or upgrading to new scopes in the future. I don’t mind spending the extra money on the eyepiece now if it will grow with me as my skill advance. Better that than spend even more money later upgrading both telescopes and eyepieces.

But, like I said, I spent yesterday thinking that maybe I should just return it and explore other options. Besides, in a way, an Ethos on a 120ST is kind like seeing Grace Kelly out on a date with a guy like... well, me. Something’s just not quite right. (Sort of like the Christie Brinkley / Billy Joel syndrome...)

But, then something happened to change my mind. First, I did a bunch of research last night and stumbled upon this thread over in the eyepiece forum. The long and short of it was that the OP on the thread was having the same trouble I was having with the 13E. He found viewing the moon to be troublesome and uncomfortable. The advice he received was to spend some time looking at DSOs instead and that this type of viewing would be more comfortable. Apparently the bright moon caused extra pupil constriction in the eye which did not match up well with the exit pupil on the Ethos, causing the need to move the eye and head back and forth. But, on less bright objects the eye’s pupil is wider which allows for more comfortable viewing.

It just so happened that last night was not only cloud free, but also much warmer than it has been here in Michigan. (It felt like 20 degrees rather than -5 degrees... almost beach weather!). So, after everyone went to bed I brought the 120ST and the Ethos back outside to give the relationship another chance. The only trouble was that the moon was full and near apex which drowned out nearly everything else in the sky (along with the horrible Detroit light pollution I live under). But, I could find M42 and M45 easily enough so I spent about a half hour just studying those two.

What a difference! I had looked at the Pleiades and the Orion Nebula before in the past week, but it had been so cold I couldn’t relax and enjoy it. Now that I had time to enjoy the viewing without freezing to death, I found the Ethos much more comfortable. Not only that, but I really started to see what all the fuss was about.

Unlike the moon, when viewing DSOs through the Ethos I found the experience much more like looking through a window. I could see a lot of detail out of my peripheral vision, and I was able to tilt my head and move my eye to examine those images off to the edge. And, of course, the field of view is just stunningly huge. Unfortunately, because of the nearly full moon I was not able to see a lot of detail in M45 or M42, but what I was seeing was sharp as a tack from the center of the view to the edge and was just stunning.

Now I just need to get rid of the full moon, get away from the light pollution and learn how to find more DSO’s than just the easiest ones.

So, in the end I think I’m going to keep the Ethos, even though people will see us together and say: “What is SHE doing with THAT guy?” It does mean that it will take me that much longer to save up for the new focuser and the filters and any additional eyepieces I may want. But, I feel now that I have the backbone of a very nice, portable rig to view the night sky with. It may not be the best scope for planetary viewing, but my interests are more remote anyway.

I’m starting to think about it like this: I bought a really great eyepiece that allows really stunning views of the night sky; the kind of eyepiece you might consider a family heirloom. So, to accessorize my fancy new eyepiece I hooked it up to a cute little portable telescope so I can take my Ethos camping with me to beautiful dark northern Michigan skies once summer comes. :)

Here’re a few additional items that are on my mind about the 120ST:

1. The EZ Delux finder is great. However, for things near the apex I have to get down on the ground to line up the sight. Maybe a right angle finder would work well in conjunction with it. Maybe an inexpensive 38-40 degree eyepiece would work just as well or better as a finderscope (from Orion’s Q70 line, perhaps?)

2. The fine tuning controls on the AT Voyager started acting up last night. In some positions either or both the altitude or the azimuth adjuster stopped working. When this happened it only affected one direction. I could move it down but not up or left but not right. After experimenting I found that this was happening when I had the Ethos on the scope, but it worked fine otherwise. So, I figured it was a balance problem. I shifted the scope forward in the tube rings and this seemed to have improved the situation. I hope nothing is wrong with the mount. That would be annoying.

3. A minor annoyance. I’ve found that I much prefer sitting to standing or kneeling while viewing. I have a nice cheap, collapsible chair to view in, but the height of the eyepiece is much different at apex than at about half way up from the horizon. This means I have to change the height of the tripod legs in order to remain seated to view what I’m viewing. Not a huge deal, but cumbersome. I think this will encourage me to pick one object and spend a lot of time studying it rather than bouncing around the sky. This is probably a good thing, but I wish I could just crank a handle and have the scope raise and lower while I sit in my comfy chair.

4. The eyepiece holder of the diagonal often resists pulling the eyepiece out. It sticks and forces me to wiggle it around after unscrewing the restraining knob all the way. (It is Orion’s 2” dielectric diagonal.) I don’t like wiggling, twisting and turning the Ethos when I try to pull it out of the diagonal. I may return the diagonal for a different model.

5. Once I save up enough, I plan to get a new focuser. Although it is expensive, I am thinking seriously about the Moonlite. The reason for this is not only because it has a great reputation, but also because it comes with an optional shorter than normal draw tube. After some research I’ve learned (and concluded myself) that the 120ST’s standard draw tube cuts into the light cone, effectively reducing the scope’s aperture. I believe that a short draw tube focuser may reduce or eliminate this problem. (I discussed this problem in another thread over here.)

6. I want to try some different filters, to improve images of the moon and to reduce CA, but so far stopping down the lens has improved the view of the moon and I’ve only seen CA on Venus. In fact, I haven’t observed CA on anything but Venus. I haven’t seen that purple fringing on any stars, on Saturn or on the moon. Maybe it’ll be more of a problem once I’m out under darker skies, but not so far. I’d like to get a v-filter, but I think I’d rather get the focuser first.

7. Regarding future eyepieces to accompany the 13mm Ethos and the 4.3mm Antares, I’m considering an inexpensive 2” 32-38 degree “finder” eyepiece, something of a bit better quality in the 20-30 range and perhaps a 2x or 2.5x Barlow. I’m thinking that this may be all I need. At this point it seems like the 13E may cover the 10-20mm range. And, a 2x Barlow will jump the Ethos up to just under 100x, which, in theory, might turn it into my planetary eyepiece. This is all conjecture given my beginner status. I need more experience to make sure, but it’s fun to develop theories to test out.

8. Wayne W. mentioned the color of the OTA earlier. I was surprised and delighted when I opened the box and it was black instead of gray. I assumed I was getting a gray one because I didn't buy the scope/mount package, but I guess not. I'm very pleased. It does look cool.

9. Mr. Wang, thank you for the information about filters. I've bookmarked it for more careful reading later. Everything on that page was information I didn't know. Very helpful!

10. I wish I could have tried both the Porta Mount and the AT Voyager before buying. The Porta Mount looked a bit more portable but the Voyager looked more stable. For those considering it, I do really appreciate the Voyager. Aside from the poorly located azimuth extension cable, the only thing I question is the length of the legs. They just seem a bit too short. I may have to take Wayne W.'s advice and pick up the 8" mount extension tube. Alternately, I hear people have had good luck swapping the legs out with wooden legs from Hands On Optics over here. I need to look into this more.

Oh, and Doctor Noodle, I'm pleased to see that we have more than one hobby in common. I quite like your model work as well!

I can’t wait for more warmer weather and darker skies. Then all my effort into researching equipment can shift gears into researching DSOs.

120ST f/5 - Thoughts after 1 week

Note: this is being simul-posted over at Cloudy Nights... here.

A short recap: Last September I went to a huge public star party sponsored by several local amateur astronomy clubs in SE Michigan. That night I got hooked and the next day I started researching scopes and planning to buy my first one. After some time I determined that my 2 main criteria were the ability to see DSOs as well as portability (with some ability to also view the planets and moon when the desire hit me) so I settled on Orion's 120mm f/5. In November of 2008 I posted this inquiry on CN asking for some advice and guidance regarding accessories and whatnot. I received a lot of really great advice from the 120ST fans on CN!

So, after saving up for months, a couple of weeks ago I bought the following items:

1. 120ST OTA (Orion)
2. AT Voyager alt-as mount (Astronomics)
3. 2" Dielectric Diagonal (Orion)
4. EZ Finder Delux (Orion)
6. 13mm Ethos (Orion)
7. 4.3mm W70 Antares (Agena Astro)
8. A 5.91" (150mm) lens cap (Agena Astro) (To build a stop down mask)

(My thanks to Doctor Noodle for the specifics on how he made his stop down mask here. I also saw that he liked the Antares eyepiece for planetary viewing which led me to try that one also.)

I've had the OTA, mount, 4.3mm eyepiece and a 25mm 1.25" Kelner eyepiece (found in the basement) for over a week now and the Ethos finally arrived last night. It has been mostly cloudy here in SE Michigan for weeks now, but I have had a few clear nights with the new scope, including last night with the Ethos. However, it has been bitter, bitter cold here and each of my viewing sessions only lasted 15-20 minutes each, so my experience with the new rig is quite limited so far. But, I'm pretty excited about it so I wanted to post my first thoughts as well as some concerns I have.

But first, here are some pictures:

The whole kit-n-caboodle.

The eyepiece end.

The business end.

Here's the stop down mask.

And here's the back side of the stop down mask. I found that those little blue Lego pieces were just right to shim the cap down to the perfect size. (I did not cut the hole in the cap myself. I work for a small laboratory where they have a computerized mill. One of the scientists there spent over an hour programming, testing and then cutting an 80mm hole in the cap for me.)

I also purchased a small notebook to keep a record of my viewing sessions. I thought I'd report on my time so far with the 120ST to highlight what I like and don't like about it so far.

On my first evening out (2/1/2009), it was actually fairly cloudy. I couldn't see the stars, but the moon was visible through the haze. I didn't have many expectations, but I was dying to try the scope out so I bundled up to brave the cold.

First I tried the 25mm Kelner (24x). I really didn't have high hopes about this cheap, old eyepiece, but even though the crescent moon was partially obscured by the hazy cloudcover, I really saw a surprising amount of detail. I was pretty impressed. Then I tried out the 4.3mm Antares on the moon (140x). It was really too powerful an eyepiece for lunar work. At 140x the image of the moon was larger than the field of view and I wasn't able to focus in on the details at all. Everytime I touched the focuser the whole image would wobble for several seconds. I had to focus a little bit and then wait to see if it focused properly and then try again until I got as close as I thought it would get. Not a lot of fun. 24x was much more pleasant.

That night I noticed two problems with my setup. First, the focuser is a weak point at higher powers. It is so stiff that the effort involved in changing focus to set the whole rig to trembling. This may be improved by putting wooden, instead of aluminum, legs on the tripod, but the main problem seems to be the focuser. The second problem was not with the scope, but with the location of the fine tuning knobs on the AT Voyager. Well, the location of the knobs themselves is ok, but when the extend-o'-cable is added to the azimuth fine tuning control it is positioned poorly. Here's a picture.

It is a bit hard to see, but what happens it this: When you raise the scope to point high in the sky, the handle of the fine tuning cable smacks right into the focuser knob. That in itself is just kind of annoying. You have to pull the cable out of the way every time you raise the scope to view high. The other bothersome part is that the fine tuning cable is very thick. After you have pushed it out of the way it rests firmly against the body of the scope and applies pressure on the OTA. At low magnifications I don't think it is necessarily a problem, but at high powers I suspect it adds to the shaky nature of the image. I may have the cable installed improperly, but I don't know where else to put it except on the opposite side of the support arm where it is impossible to reach. I tried placing the extension cable on the altitude knob, but then the azimuth knob is harder to reach. I'm not sure if others have had this problem. I guess I could try bending the cable, but I'm a bit worried about damaging it.

The next morning at 6am (2/2/09) the skies were totally clear, but it was still bitterly cold. I dragged myself out of bed early just to view Saturn. (I used StarryNight the night before to figure out when and where I could see it best if the clouds went away.) First I tried out the 25mm Kelner again and could just barely tell that it was a bright dot with a diagonal line through it. Then I tried out the 4.3mm Antares and got a better view. It wasn't what I would call "great" but I definitely tell it was Saturn. I couldn't see any real details, though, and the rings were pretty much edge-on so it looked like a slightly bigger, smudgy circle with a line through it.

Again, the focuser proved its shortcomings. I just couldn't get a distinct image. However, one thing I did not notice, which I had expected, was the purple fringing of color aberration. I only stayed out a few minutes due to the cold, but I felt that with a better focuser and more time I could have seen a more distinct image. However, I'm not sure if 140x is really enough to see a lot of Saturn, but I'm not sure if the scope can handle a lot more than that yet.

A couple of nights later, on 2/4/09, I finally got some evening time with clear skies. I mostly work late afternoons and evenings so coming home from work and then hauling the telescope outside before settling down with the family works out well. That night I tried the 25mm Kelner on the moon again and was again impressed with the clear, beautiful image. Focusing was still a bit problematic, but not terribly so. Again I so no color aberration.

The moon was pretty high in the sky and was nearing 1/2 full so not only was I dealing with harsh city lights (I live not far from Detroit) but the bright light of the moon was also making for poor seeing. Because of my inexperience, the cold and the bright sky I was limited to viewing things I could see easily. So after the moon I found my way over to the Pleiades (M45). Because it was near the moon it was not terribly visible to the naked eye. However, the 25mm Kelner really brought out a lot of detail. It was pretty nice.

After that I popped the 4.3mm back in and pointed at Venus. Again I had a hard time focusing, but this time I also got a big eyeful of purple fringing for the first time. I threw on the 80mm stop-down mask for the first time and this cut the ca down by about 1/2. I could definitely see Venus' crescent shape though, which was kind of neat. I will definitely need a fringe filter of some sort, though, if I keep pointing it at the brighter objects. I'm curious to see how Jupiter will look, but it isn't visible right now.

This was also the evening when my wife came outside with me for the first time and had a look for herself. She did a lot of "oooing" and "ahhing" over the moon and Venus. She seemed pretty impressed and we had fun later planning to take the scope camping with us this coming summer (which is mainly why I wanted a more portable scope in the first place.)

Then, last night, at long last, FedEx finally delivered the 13mm Ethos, which had been on back order from Orion. I have to say I have mixed feelings about buying such a premium eyepiece. It feels a bit silly to pay twice as much for an eyepiece as for the OTA. But, at the same time, if I stay with this hobby for a long time, it makes sense to me to buy a few high quality eyepieces which I'll likely keep forever and which I can use in any scope I might buy later.

So, last night, 2/5/09, I hauled the rig back out in the back yard and plugged the Ethos into the diagonal. I have to say... Wow, this eyepiece is big and heavy. It is very impressive just to hold in your hand.

The first thing I looked at with the Ethos was the moon, which was approaching 3/4 full and was still very high in the sky, drowning out almost everything else. The view of the moon at 46x with the Ethos was noticeably different than through the Kelner at 24x. First, the image was much larger and much brighter. Second, the moon looked much more 3-dimensional than in the Kelner. Now, that being said, I had some difficulty finding the right eye placement over the Ethos. It was a bit awkward. I hope that gets easier with practice, but it was a little odd the first time.

Also, after just a few seconds my eye started watering and hurting. The image was just too bright and a bit painful. So, I stopped the mask down to 80mm, but it still hurt my eye. When I used the original lens cap and removed the built in 50mm mask cap I finally got an image of the moon that was just as beautiful as before, but not quite so painfully bright. I could actually manage to look at the moon for a couple of minutes without having my eye water profusely.

After that I tried to look at the Pleiades again, but the moon was too bright and too near it and I couldn't even get a bead on it through the EZ Finder Delux. (Also, looking at the moon had hurt my night vision considerably.) But, I could find Orion's belt well enough so I swung over to M42. Once there I took a few minutes to compare the 13mm Ethos with the 25mm Kelner and was again impressed (after removing the stop down mask). The Ethos showed a lot more detail of the M42 nebula, although the city lights and the moon still interfered quite a bit.

I'm still a bit on the fence about the Ethos. I will probably keep it, but there are a few things about it that make me wonder. I really think I need more experience with it when it is warmer and I'm less hurried, but I did find the eye placement a bit more difficult than with the Kelner. The image is much better, and more 3-D like and has a considerably wider FOV, that is true. My big trouble is that I lack experience with other more similar eyepieces. I wish I could compare it with a 12T4 or a 17T4 or even a larger eyepiece from the Orion Q70 line. I just don't know enough to be able to say for sure that the Ethos is worth the extra money over these other premium (and not so premium) eyepieces. I could exchange the Ethos for a similarly sized Nagler and still have enough left over to buy a new focuser. I need to spend more time with it to be sure.

Also, the moon in the Ethos is almost TOO big and majestic. Looking at the moon through the Kelner I said to myself: "Wow, that's a really nice clear view of the moon." But, looking at the moon through the Ethos I said to myself: "Holy cow! The moon is going to fall on me!" It was a bit overwhelming. I wonder if it would be more subdued in the 17mm Ethos. To bad that one costs so much more, even than the 13mm. Something to consider though. The 13mm Ethos might be too much power for the 120ST. It's too early to say, though. I need to view more clusters and nebula to really get a feel for that. Or perhaps I'll try out a larger Orion Q70. Those are only about $100.

Overall I'm very happy with the 120ST so far, even though I've just scratched the surface of its potential. The OTA on the AT Voyager mount is very easy to pick up and carry outside. Not counting cool down time, I can have it set up and pointed at an obvious object in the sky in less than a minute. And, if I want to move around the yard it's as easy as picking it up and moving it. Nothing to it. The EZ Finder Delux is very easy to use, except that it does take some bodily contortions to line it up high in the apex of the sky. The whole rig is extremely portable and easy to use. I can't wait to have warmer, darker nights so that I can take my time finding my way around the host of star clusters, nebulae and brighter galaxies that I hope to see one day.

I've also been reading Turn Left at Orion and have just ordered Sue French's Celestial Sampler and am planning out my stargazing once the weather gets better. In addition I've been reading the Wikipedia entries on the Messier list, the Caldwell Catalog and the Herschel 400 Catalog so that I have lots of things to try to find later this year.

I'm really looking forward to improving my knowledge of the night sky. For the long term I'm also considering a big dobsonian to compliment the 120ST.

One step at a time, though.

My apologies if this was much too long. But, I'm having a ton of fun with this new hobby and I've never been good at being brief when I'm having this much fun.

Orion 120ST f/5 Short Tube Refractor - Home at Last

Phew! After months of research and a week of waiting after I ordered it, my new telescope, the Orion 120ST f/5 finally arrived. The scope is mounted on an Astro-Tech Voyager portable Alt-Az mount. Here are a couple of pictures.



Unfortunately I haven't had a chance to really use it yet. I've ordered two eyepieces but neither one is due to arrive until next week. I did scavenge a 25mm Kelner eyepiece (24x power) from an old kid's scope in the basement so I can use that.... except that it's been both cloudy and snowing since the scope got here on Tuesday.

However, the snow stopped this afternoon and I hauled the 120ST out to the front yard. It's daylight and cloudy, but I wanted to test the focus and make sure the finder scope was lined up properly. So, I pointed the scope down the street about 1/2 mile. It turns out that the cheap eyepiece isn't too bad. The focus was crystal clear and I was able to read license plates from 4-5 blocks away (backwards). And I was able to line up the finder scope pretty well.

Actually, the finder tool I use isn't really a "scope" at all. It's a small laser that points at a little glass viewfinder. It doesn't magnify anything, but the laser throws up a little reticule target on the glass which you line up with your target in the sky. The 120ST has such a wide field of view that you don't really need a separate finder. I'm still tempted to get a right angle, correct image 9X50 finder for it also someday, in addition to the EZFinder-Delux, just so that I don't have to contort my back in crazy positions to sight up with something in the sky.

So far I'm pleased enough with the optics. I've heard that some people have gotten poorly collimated copies of this scope and have been forced to return them. There's a 100mm version of this scope that comes with the ability to collimate the objective lens, but this 20mm larger version doesn't have that ability for some reason. (Collimation is the process of adjusting the lens to make sure it is pointed exactly straight down the tube towards the focuser and eyepiece.)

The other bonus is that I've confirmed that I can carry a small chair and a box with the diagonal and eyepiece under one arm while carrying the mount and scope with the other and haul it all outside in one trip. Setup was fast as was teardown. The whole process was really easy, which was extra nice since it is pretty freakin' cold outside.

The next step in the process is to try the 120ST out under clear skies. When my 13mm Ethos and the 4.3mm Antares eyepieces arrive I can then test the focus on the moon and run a "star test". That will also tell me how well the lens takes a focus and how well collimated the objective is.

Instructions and a description of "star testing" can be found here.

More later, when the sky clears up. Shoo, clouds, shoo!

Night Vision - Part 3

So, after all the research I've described in previous posts below, one overarching fact became obvious to me. If I wanted the best possible views of planets, nebulae, star clusters and galaxies in a relatively inexpensive package, then I should buy the biggest possible Dobsonian Reflector.

Here's an example of a 10" Dob from Orion Telescopes. It only costs about $500.00 before any accessories are added. And the only extras it might need are additional eyepieces, a better finder scope and maybe an improved focuser if you're picky about such things. The only trouble with this is that it is 10" in diameter and 4' long and weighs 55 pounds.

If portability wasn't an issue for me, then this is probably the telescope I would have purchased.

But, because I really wanted something portable and have been having fantasies about taking a telescope camping with us, I had to come up with another plan.

I started looking at either refractors or cassegrain scopes, but those tend to have either small diameter apertures or long focal lengths which mean they are better at viewing planets and the moon than they are at DSOs like nebulae or star clusters. Since I wanted to look at everything I could in the sky I knew that a standard refractor or cassegrain probably wasn't going to work for me.

Eventually I decided to purchase the 120ST refractor from Orion telescopes. The 120ST can either be purchased as a package, with a mount, tripod and eyepieces or it can be purchased as a simple optical tube assembly (OTA). The name of this telescope, the "120ST" means that the objective lens is 120mm in diameter (about 4.7") and that it is a Short Tube scope. The focal length is only 600mm long which gives it a focal ratio of f/5.

The fact that this is a 120mm f/5 scope means that it has some interesting characteristics. Some of these are benefits and others are drawbacks. The 120mm diameter lens is a definite plus because that is large enough to start getting some somewhat good views of deep space objects. At the same time, because the tube is so short, at only a bit longer than 2' and because the OTA only weighs about 8.6lbs, it is pretty darn portable. It's what amateur astronomers like to call: "Grab-n-Go". Also, because it is a short f/5 it should provide very wide fields of view, allowing the user to see large swaths of the sky at low to medium levels of magnification.

However, there is a big draw back. A scope like this will not be nearly as good as an f/8 or f/9 scope at viewing the planets and the moon. There are two reasons for this. First, because magnification power results from dividing the focal length of the OTA by the focal length of the eyepiece, a short tube scope has a hard time generating big magnifications. It isn't impossible, it just means that you either need a very small eyepiece or a special "barlow" lens which provides additional magnification.

The bigger drawback is this: Color Aberration (CA). This happens when you point a short tube refractor at a bright object (like a planet). What happens is that the light coming into the lens is bent at much sharper angles in an f/5 refractor than in an f/9 refractor. When the light is bent like this some wavelengths at the purple end of the spectrum are sent off at a slightly different angle than the rest of the light. The result is that you will see a purple halo around bright objects.

So, I had to decide if this was a big deal for me. In truth there are only a limited number of really bright objects in the sky to look at. Planets are interesting, but Mercury is hard to see anyway, Venus is kind of boring to look at and Uranus, Neptune and Pluto are both hard to find and not very bright. So, the only problems the 120ST would really have would be for The Moon, Mars, Jupiter and Saturn. That's only 4 objects out of all the hundreds of other less bright objects in the sky.

(Addendum: This isn't precisely true. Stars can also be interesting to look at, especially if they are in clusters or if you are trying to "split" close binary stars. That does add a lot more bright and possibly problematic objects I might want to look at through the scope.)

But, even if that is a problem, it turns out that there are two solutions to fix (mostly if not completely) the color aberration problem. First, you can get a special filter which fits on your eyepiece which filters out all the purple so you can't see it anymore (or at least you see a lot less of it.) These filters cost between $50 and $150 dollars depending on how good an effect you want. I've been eying a more expensive filter here.

Second you can also partially solve this problem by changing the focal ratio of your telescope. If you can somehow turn your f/5 scope into an f/7 or f/8 scope, then a big chunk of the color aberration problem goes away. This is how it works. The lens of the 120ST is 120mm in diameter. The focal length is 600mm. 600/120=5 which gives you an f/5 scope. But, if you place a cap over the main lens with an 80mm hole in the center of it, then now you have an 80mm lens. 600/80 = 7.5. So now, just by covering up part of the lens you have magically converted an f/5 scope to become an f/7.5 scope which should have much fewer problems with color aberration. It is true that, because of the smaller aperture, the image will be a bit dimmer, but planets and the moon are pretty bright anyway so that shouldn't be a big deal.

So, the long and short of it is that I decided on the 120ST because it was light, portable and, in theory, should provide nice images of deep space objects. Its ability to view the moon and the planets is problematic because of the fore mentioned problems, but these difficulties are not insurmountable and there are cost effective workarounds to solve them.

When I came to these conclusions I was finally settled that this was the scope I wanted. So I made a post on the Cloudy Nights forums describing my decision making process and asking for advice on how to optimize this portable scope to be good (but not necessarily great) multipurpose scope for viewing the moon, planets, nebulae, star clusters and galaxies.

I got some great advice from that thread, which helped me finalize all my decisions about exactly what I wanted, including eyepieces and other accessories. That thread can be found here. I won't bother to summarize it all again since this post is already long enough.

Suffice to say that after months of research I finally decided on exactly what I wanted out of a telescope and last week I ordered it. As I write this my new scope and almost all the accessories are on a FedEx truck to be delivered later today. The only thing I won't have yet is the eyepiece I bought, which was on back order and will be shipped later this week.