For my astrophotography (otherwise, location is where I was at the time), all the images on this site were taken in Colorado, either outside of my apartment in Westminster, or at the Sommers-Bausch Observatory (SBO) on the University of Colorado at Boulder campus. The 24" telescope dome here is located at 105° 15° 47" W longitude, 40° 00' 13.4" N.

Boulder gets generally very sunny weather - supposedly we get more sun than California - and pretty low humidity. This is good for astronomy, as telescopes can't see through clouds (though introductory astronomy students seem to think they can, since they'll show up for an observing lab in the middle of a blizzard). However, we have mountains just to the West, and so the air coming over the mountains means that we have a very turbulent atmosphere overhead. This severely limits the seeing - the blurring of an object caused by the atmosphere - and so while the equipment that I have and is available to me may be able to get fantastic resolution, I am unfortunately bound by what the atmosphere decides to do.

Consequently, on the "Deep-Sky Objects" page where I have nebulae, galaxies, and clusters, you will notice that stars do not appear as points -- rather, they are circles with sometimes a very large size. This is because the atmosphere acts to blur everything, and in Boulder, the best seeing, in general, is about 5 arcseconds. This means that this is the smallest an object can appear in the telescopes, or the smallest detail we can observe on an object. For stuff like the moon, this doesn't matter, since the moon is 600 times larger than that. But for stuff like planets, clusters, nebulae, and especially galaxies, it will cut down on the detail that is visible by a large amount.

Another factor to contend with when observing in Boulder is city lights. We're in the middle of Boulder, and we're less than 40 miles from Denver. From the observatory, there is a noticable glow to the South-East, which is Denver. Consequently, it is difficult to observe fainter objects (nebulae, galaxies, small globular clusters) in the telescopes, though I've become pretty good at removing skyglow from my images in post-processing.


Canon Digital Rebel XT 350D - A "pro-sumer" model, so-called because it is a class of camera that can be used for professional work, but it is (sort of) within a consumer's price-range. This is a digital SLR camera, which means that it has a body that can be attached to various lenses, which is what I was looking for when I bought it in August of 2005. Because it can be hooked up to various lenses, it can also be attached directly to any telescope that has an eyepiece. This 8.2 Megapixel camera is great, and I relied ont it exclusively for over 4 years, and I still use it often and as a backup.

Canon Digital 7D - I'm not certain if this is a very high-end "pro-sumer" model or if it's a low-end "professional" camera. Regardless, this camera was introduced by Canon on September 2, 2009, and I pre-ordered it and obtained it about a month later. It is also an SLR camera like the Rebel, but it being a higher-end model and released 4 years later gives it a significant advantage over the Rebel. Its low-sensor-noise capabilities are significantly better, allowing better performance in low-light situations (such as astrophotography or weddings). It has a much better auto-focus system, in-camera sensor cleaning, and full-HD movie capabilities. It also acts as a Flash Master, meaning that it can trigger other flashes from the camera itself, rather than needing a flash master on the camera and using up one of your flash units.

ST-2000 - This CCD (CCD = charge-coupled device, which is a fancy way of saying "digital") camera was bought by the University of Colorado for one of their telescopes in May 2006, and it is a "real" astronomical detector. What I mean by this is that it is much more sensitive than normal detectors in cameras, and the noise level (if a detector has any temperature, the electronics in it will actually produce an image on the detector called "noise") is very low. Plus, the camera can be cooled to reduce the noise. It is a 600 by 800 pixel detector, so it has lower resolution than my Digital Rebel, but because of the quality of the detector, it is much better-suited for astronomical imaging, which is why I use it now for my deep-sky imaging of objects that will fit into the field of view of the detector (a little smaller than the Full Moon). It has a 3-color detector, just like consumer digital cameras (but unlike professional astronomical detectors), and so in one exposure you can create a full-color composit image.


Canon 35 mm f/1.4L - My first very professional-level lens. It's nice. I especially like it because I can effectively take what was before a 300-second image of a constellation in about 30 seconds (since the amount of light gathered is proportional to the f/number squared).

Canon 24-70 mm f/2.8L - Canon's professional "Luxury" zoom lens for the wide- to standard-focal lengths.

Canon 70-200 mm f/2.8L IS - Canon's professional "Luxury" zoom lens for standard- to telephoto-focal lengths. This lens also has image stabilization on it, allowing one to shoot approximately 3 shutter speeds slower when hand-held than normally possible.

Canon 18-55 mm f/3.5-5.6 - This was the lens that came with my camera as a "kit" lens. It's not great, but it gets the job done. The field of view of this lens is 65.5° to 23.3° horizontal by 45.5° to 15.7° vertical. My Digital Rebel has a multiplicative factor of 1.6 (because the detector in it is smaller than a 35 mm film), so the lens is an equivalent of 29-88 mm on my camera. It takes 58 mm filters. The minimum aperture is f/22 at 55 mm.

Quantaray 70-300 mm f/4.0-5.6 with Macro - I bought this lens shortly after I bought my camera to get a decent zoom lens. It has a field of view of 29° to 6.8° horizontal by 19.5° to 4.6° vertical. With my camera, it's the equivalent of 112-480 mm, so its field of view is approximately 19°-4° by 13°-3°. It takes 62 mm filters. The minimum aperture is f/32 at 300 mm.

Quantaray 600-1000 mm f/9.9-16 - I bought this in June 2006. It uses a t-ring adaptor, which means that it does not have an automatic focus ... but it also means that it can be hooked on to any kind of camera that takes different lenses. It has a field of view of 3.5° to xx° horizontal by 2.3° to xx° vertical. This has an equivalent focal length of 960-1600 mm on my camera, so its field of view is approximately xx°-0.9° by xx°-0.6°. It takes 72 mm filters and 77 mm filters (when using the hood). This is a great lens to use to photograph the moon, since the full moon just fits within it with a small margin around it at its largest magnification.


UV Filter - UV filters in photography are mainly used to protect the lens. I have a 58 mm and 62 mm one.

Cross-Screen Filter - This filter is used to make spikes on small bright points of light. I use it to add the spikes onto bright stars in my images that I take with my lenses and without the telescope. I have a 58 mm and 72 mm one.

Circular Polarizer Filter - Just like polarizing lenses on glasses help to reduce glare, this does, as well. I have a 58 mm and 62 mm one.


3" (7.6 cm) aperture, 20" (51 cm) focal length, f/6.5 Refractor - This is the finder telescope on the SBO 16" telescope at CU Boulder. It has a huge chromatic aberration, and it produces glare around bright objects. Other than the tracking capability of the telescope that it's mounted on, my 600-1000 mm lens is far superior. It's a telescope lens to use for photographing open clusters.

8" (20.3 cm) aperture, 80" (200 cm) focal length, f/10 Cassegrain - This telescope is mounted on the SBO 18" telescope at CU Boulder. It's not the greatest, but it is what the ST-2000 camera is mounted on. With the ST-2000 camera, it has a field of view a little wider but a little shorter than the full moon.

16" (40.6 cm) aperture, 192" (488 cm) focal length, f/12 Cassegrain - A good telescope for what it's supposed to do, it has a field of view around 15x10 arcminutes (1/2 by 1/3 of the full moon). Its tracking with my camera fails after about 3 minutes, and I have trouble focusing with it, so I don't use it anymore for photography other than for my moon panoramae. Almost all of the large images I've taken of the moon, including my phases compilation, were taken with this telescope.

18" (45.7 cm) aperture, 270" (686 cm) focal length, f/16 Cassegrain - This telescope has a flip secondary mirror which can put it into f/8 mode with a 3.66 m (144") focal length. This gives it a lower magnification, and I'm also unable to focus it using my camera in this mode. I also generally have focusing issues with it, and I only use it now in f/16 mode to photograph planets with my Digital Rebel camera.


Tripod - I have a simple tripod that I sometimes take out to use for photographing panoramae near my apartment. SBO has several tripods, including some very heavy-duty ones that are required for my heavier lenses.

Telescope Mounts - The 3" is connected to the 16" / The 8" is connected to the 18" ... (to be recited in song format to the tune of "The neck bone is connected to the shoulder bone, etc.). And the 16" and 18" telescopes are mounted on giant equatorial mounts, guided by clock drives (so a passive guide system). They can be set to sidereal track (the rate of the stars) or lunar track (the rate of the moon). For photography, the 16" fails after about 3 minutes, the 18" after about 5 minutes, and for the camera on the 8" telescope, 8-10 minutes is about as long as you can expose without seeing star trails.

Clock Drive Tripod - The manager of SBO had a swell idea when a small telescope that had a clock drive broke: He took off the telescope, and he attached a metal plate to the mount. The allows the mount to be used as a tracking system, and you can drill holes in the metal plate and attach all sorts of instruments to it. I use it to attach my camera when I use a normal lens rather than a telescope. With my 18-55 mm lens, I can get point-like stars after 10 minutes; with the 70-300 mm lens, it fails for tracking purposes after about 40 seconds, and 30 seconds is as long as I can expose with the 600-1000 mm lens before seeing star trails. It also does not have a GoTo feature, which means that I have to find whatever I'm imaging by eye.

Image Processing Software

Stitcher - I use RealViz's "Stitcher" software to stitch together multiple images into a single one. Any moon image, for example, that I took with the 16" telescope was first stitched together with this panorama software.

CCDOps, IDL, IRAF - Images that come off of the ST-2000 camera are arithmetically processed in CCDOps, which is the software that's also used to run the camera. I use it to stack multiple exposures, dark-subtract, and flatfield. Otherwise, images that come off of my Digital Rebel are processed in IDL. I use IDL to stack multiple exposures, dark-subtract, and I flatfield in it by fitting a 2-D polynomial to the image and dividing by the fit. This takes care of vignetting, but not small dust that gets on the camera and lens elements. I had used IRAF for this task, but I found it (as most do) too clunky and limited to be worth it.

PhotoShop - I'm now onto PhotoShop CS 2 (AKA PhotoShop v. 9.x). I use PhotoShop to first re-combine the R, G, and B color channels, adjust levels, curves, color banalce, brightness and contrast, and I use it to sharpen or blur, depending upon what effect I'm going for. For my open cluster shots and star fields, I use it to add the glow around the brighter objectes, and I also use it to label stuff when there are labels in the images.