Monday, September 15, 2008

Orion Skyquest XT8 Classic Dobsonian

The time for a review of my new telescope has finally come. First of all, here is an overview of everything I purchased:

Orion Skyquest XT8 Classic Dobsonian

  • Optical tube assembly (OTA), 8" aperture, 1500mm focal length

  • Disassembled mount

  • Various tools for assembling the mount

  • 25mm Sirius Plossl Eyepiece

  • EZ Finder II viewfinder

  • Collimation cap and dust cap

Padded carrying case for the OTA

Celestron 1.25" eyepiece and filter kit

  • 4mm, 6mm, 9mm, 15mm, 32mm Plossl eyepieces

  • 6 colored lunar and planetary filters

  • moon filter

  • 2X barlow lens

I already had a green laser pointer (generally useful for everything) and various star charts. So how does everything hold up? Let's see...

Assembly of the mount: They say that assembly of the mount takes about 30 minutes. Working by myself, it took me more like an hour to put it together, but I didn't have all the correct tools readily available and I was a tad bit distracted by SBCGFAP (Strong Bad's Cool Game For Attractive People), which was just released that day. Nevertheless, the directions were very clear and I generally had no trouble with the assembly, except for improvising the tools I didn't have.

Number of observations: So far I have used the telescope three times. The first time was the night I assembled it, in an extremely light-polluted back yard, on a really hazy night. I saw Jupiter and that was about it. The second time I took it out in the Gerig backyard, which is moderately light-polluted but not all that bad. I was able to see Jupiter in better detail, a couple stars (including a double star), and a star cluster or two. The last time was a couple nights ago, and this time I drove about 5 minutes out and parked on the side of the road where there were no lights at all and the sky was clear. This time the moon was in its waxing gibbous phase so it was difficult to find some things that I wanted to see.

Sturdiness of mount: Being a dobs, the telescope is very sturdy. An equatorial mount would have been nicer to have than an alt-az, but the sturdiness of dobsonians plus their relative cheapness per inch of aperture made it worth it. (All dobsonians are alt-azimuth.) However, the mount was very steady and never wobbled.

Size/weight: Both the OTA and the mount are fairly sizable. I can easily sling the OTA in its padded case over my shoulder and carry the mount and the eyepiece kit in either hand, but I wouldn't want to carry it more than half a mile if I can help it. When the telescope is assembled, it can be carried as a unit, but it's awfully heavy and requires both hands.

Assembly: Attaching the OTA to the mount is a breeze. Just set it down (doesn't matter which direction as long as the open end is up, obviously), pull down on the springs and hook the springs over the pegs on the sides of the mount and you're ready to roll. Seriously, taking it out of the case is harder than setting it up.

Eyepieces: The telescope is advertised as being able to switch eyepieces without losing the object you were centered on, and this is true as long as you're careful not to bump it. I mostly switch between the 32mm, 15mm, and 9mm. The field of view in the 32mm is really nice. The 4mm is practically useless; it magnifies like you think it should but it's impossible to focus so everything is terribly blurry. The 2X Barlow lens is nice to have, but I haven't used it much so far. The eyepiece that comes with the telescope (a 25mm) is nice, but if you are going to do any serious observing you need to purchase a wider range of eyepieces. It accepts both 1.25" and 2" eyepieces, which would be nice if I actually had any 2" eyepieces to use.

Filters: I tried out a couple filters during my second observing time. They're pretty nice, but I don't yet have a sensitive enough eye to be able to fully appreciate them. The moon filter is really nice for lunar viewing, as I practically blinded my right eye without it when observing the moon. It's about 18% transmission. Although I haven't quite figured out how to attach it to an eyepiece yet...maybe I'm just stupid.

Eyepiece carrying case: It's nice and sturdy. I think I'm going to try to etch out a piece of the foam so I can stick my laser pointer in there too. It has ready-made slots for two extra eyepieces, and I was able to put a couple printouts of star charts in it and still shut the lid. It also locks, but the lock is akin to using an MD5 sum for transmitting password hashes-it'll keep out people who are just poking around, but if someone really wants your eyepieces they will be able to get at them.

Carrying case: I would call the carrying case as necessary as the extra eyepieces. Storing it in the case keeps it safe from bumps and nicks, and carrying the OTA is so much easier. I don't think I could live without it. It's freaking expensive though! It's about $75 just for the case, but it's worth it. The insert that came with it says that it can take lots of abuse, and I believe this is true. It seems very sturdy and well worth the money.

As an added bonus, the carrying case is ideal for sneaking several bouquets of flowers from a car to the fourth floor of some particular building without anyone noticing.

Viewing comfort: I basically have to kneel down on the ground when looking through the eyepiece, unless it's pointed relatively near the zenith, and then I can get away with bending over and not killing my back. It might be worthwhile to invest in a kneeling pad, depending on how tall your upper body is.

Collimation: Haven't done it yet. Hopefully I won't need to for some time, although I have bumped it around a little already. If I had purchased it just a couple weeks sooner I could have gotten a laser collimator for free, but alas I waited, and the deal went away. A collimation cap is included, but I'm afraid to mess with the mirror alignment for fear of making it worse. Maybe later...

Storage: I keep the mount in my trunk so I don't have to carry it everywhere. It's made of wood so it should be fine there. I keep my eyepiece kit and the OTA in my room. Even when the OTA is in its case, it can be stood upright in the corner so it really doesn't take that much space. Maybe about 1.5 ft^2 by 5 feet vertically. I'm not worried about it tipping over-it seems long as it is stored upright (with the opening up, the primary mirror on the ground). When storing it I take the viewfinder off so it doesn't accidentally get loosened and fall off in the case, which has happened once. (I don't think I tightened it enough.)

Astrophotography: Not possible. Don't even ask.

Ok, so I suppose it might be possible. Long exposures are out due to the alt-azimuth design of the mount and the inability to add motorized tracking. I read about a trick, though, where you take a cheap webcam and hook it up to a laptop and take a couple minutes worth of video through the eyepiece, equaling several hundred low-quality frames. Then you send it through a program like Registax, which picks out the best frames and stacks them together to produce a nice image. In theory it should work, but I have no webcam to try it with. Not to mention my 1+ hour laptop battery life...

Goto functionality: I purposefully bought the classic version because 1) it was much cheaper and 2) it doesn't have any automated goto features. To me, punching numbers in a pad and having the scope automatically find what you want takes all the fun out of it, and you don't really learn the sky the way you would if you found everything yourself.

And we all know how much I hate GOTO's...

Well, that's the basics of it. Is it worth every penny? It probably is, but I haven't utilized it to the fullest extent possible yet. The quality of the scope in general seems excellent, and I'm glad I made the investment. I hope to keep it around for several years and see many exciting things with it. As with just about any scope you purchase nowadays, you will definitely need to buy extra eyepieces and other accessories, and be sure you do your research before deciding on one particular type. I was dead set on buying a Meade equatorial reflector until I talked to some people and decided that a dobs was the way to go for me. At any rate, I love my telescope and am very glad I made the decision to buy it. Now I just wait for the weather to clear...


John said...

What is this?!

As an added bonus, the carrying case is ideal for sneaking several bouquets of flowers from a car to the fourth floor of some particular building without anyone noticing.


denaje said...

Haha. Summary of the story: while FOSO was on our retreat, 2G (2nd floor of Gerig) stole our shower curtains. Yesterday we pranked back by throwing them an ice cream party in their hallway, and while they were distracted we went in their rooms and hid all their left shoes. A few hours later after they started noticing we gave them all flowers. In order to get the flowers from my car to FOSO without anyone noticing, I hid them in my telescope case. It was pretty great.

Robert said...

ha ha, sweet story.

Thanks for the update on the scope! I've been waiting for it :) Not like Kalamazoo is great viewing conditions for stars tho due to the light pollution, but it's still fun here.