First Image of a deep-sky object

Tonight I polar-aligned my scope (though not very exactly) and started searching for deep-sky objects to photograph. It was far more difficult than I had expected. Though I was dialing in locations based on RA and Dec setting circles with pretty good accuracy, I was not having any success in finding objects... even in my 8x50 finder. Some of these were supposed to be fairly bright objects. I suspect that a big part of the problem is the not-so-dark skies of suburban Portland. On the verge of giving up, I finally succeeded in locating one... M3, a globular cluster. I ended up seeing it not in my finder, but in directly through my camera's view-finder, hooked up for prime-focus photography. The magnification is slightly more than when I use a 30mm lens, but the camera's field of view is cut-down. I used my standard 30", 1600 Iso, with noise-reduction 'on' (Nikon D40) and this time of course used the clock-drive. I can't say I'm thrilled with the photo (mine is the lower photo, compared with what it is supposed to look like... the top photo), which clearly isn't showing many of the stars and is probably a little out of focus, but for a first try I guess it's okay. Based upon what I see, I think that I need longer exposures, which means I need to try again with darker skies and better polar alignment. I may find I'm near the limit of my DSLR, which would probably mean I'd by a CCD camera designed for astro-photography (with cooling, hence less noise). I also need to look at accessories that allow me to use a lens at the same time as my camera, to aid in finding objects (it's harder seeing objects through the camera's finder) and focusing.

Astrophotography progress

On April 4th and 6th we had clear skies and I was able to take advantage of it with my 8" Schmidt-Cassegrain telescope (C-8 Powerstar PEC). On the 4th I experimented for the first time with eye-piece-projection photography on Saturn using a newly purchased camera adapter. I confirmed fairly quickly the difficulties that others have described with this technique. At high enough magnification to get any detail of Saturn (10mm lens), the planet was very hard to find and contain with-in the narrowed field of view that results from eye-piece projection (compounded by the relatively long focal length of my telescope and the fact that my clock drive was not working). I ended up resorting to using prime-focus photography, however the lower magnification gave me little to see except the bright planet and rings (no moons or surface detail).

On April 6th I experimented with deep space photography using longer exposures. Without my clock drive working, I got by pointing my telescope at the celestial north pole (the area of Polaris, the north star) where the motion of the stars is slower (shorter distance to cover in the same 24 hour period). I took 10", 20", and 30" exposures and was surprised to see that even the 30" exposure (included above) came out very nice (though it did show very slight motion trails). I noted a blue halo near one star, which I'm sure must be either an artifact from camera or telescope or a reflection from a high altitude cloud formation; it looks amazingly like a planetary nebula though! I'm going to investigate this further on the next clear night. I also spent time checking the correspondence between my photograph and the star maps, identifying stars and their magnitudes. My photographs captured stars that were around +13.6 magnitude, despite the poor conditions (moon, moisture, and city lights). Surprisingly, there were some stars that should have been there but didn't register... another thing I need to better understand (glare, pixel resolution... ?). I'm anxious to get my first photographs in a truly dark sky!

Since those observations, I took my telescope clock-drive over to my brother Dave's watch repair shop and looked it over with him. When I first purchased the telescope in 1993, it worked briefly and then just stopped, never to work again. At the time the Celestron technical support advised me over the phone to try tweaking the adjustment screws that hold the worm gear up against the large gear that rotates the telescope (though he cautioned me that it was a tricky adjustment). I was reluctant to mess with it at the time, but in Dave's shop we did it. Dave loosened the screws and immediately confirmed that the motor was working. He then re-engaged the gears and it continued to work, even after they were tightened. While I can't be sure until I get a full rotation, I think it's working again and I'm really excited about trying to photograph some real deep-sky objects on the next night the sky is clear. With this progress, I'm actually now in position to get drawn into astro-photography as a regular hobby. The plan is to see what I can get out of my Nikon D40, C8, and a working clock drive, before I start spending $ on any more sophisticated equipment. I was never really that excited about the views I could get through my C8, but I can get excited about what I've seen amateurs produce with CCD camera's. In addition, there's the excitement of getting real-time data, with the potential of capturing objects (e.g. comets) that others have not yet seen (though the odds are not good). At the very least, I'll extend my own experience with the night sky.