Progress in Astrophotography

I’ve been fascinated with astronomy from my early teen years. Since my father was an avid photographer, I soon started dabbling in astrophotography as my first foray in photography.

My first photos were just putting a camera on a tripod and opening the shutter for 5, 10, or even up to 30 seconds. Since the camera lens was a short focal length, the streaking due to earth rotation was minimal and the film turned out pleasing enough for a youngster.

The constellation Orion, taken with a simple time exposure on a tripod, probably with my first camera: a Canon AE-1 Program with ASA 400 film. Circa 1971. Those black lines are telephone lines; something I would _never_ have in a photograph now days.

Then in 1973, I believe it was, Comet Kohoutek came along. Billed as ‘The Comet of the Century’, the general public felt is was a dud as far as comets go. Actually, if it hadn’t been hyped so much, it would have been perceived as a fairly impressive comet. But this was still a great photo opportunity and called for a more serious approach. I designed a small fastener out of 1/4″ aluminum sheeting for attaching Pop’s Leica camera to my 3.1″ (80mm) refractor, piggy-back style. After some preliminary practicing, we realized that we would need a reticle eyepiece – an eyepiece with crosshairs in it, in order to be able to guide the exposure accurately. So we managed to glue some very thin wire exactly in the focal plane of a high-power eyepiece. It wasn’t anything pretty to look at, but it did give a reference point to guide by.

Comet Kohoutek’s closest approach to Earth came during a very cold winter. I remember fondly, Pop and I standing out there at 3am in February in bitter cold. I would look through the main telescope to visually guide the exposure while Pop would take care of the actual photography. It was so cold that the eyepiece kept freezing over and we would have to stop to thaw it out before continuing! Funny how the misery tends to be forgotten with time and we are left with great memories.

Homemade 10″ F5.6 Newtonian Reflector

Later, my father and I designed and built a 10″ (25cm) F5.6 Newtonian reflector on a beast of a German equatorial mount that my brother welded together. The total weight was around 300 pounds and the mount could easily hold a telescope twice that size! Although I was really into grinding my own optics for telescopes by this time, for this telescope we bought the mirror from Cave Optical Company. Cave was one of the leading suppliers of telescopes just before the newer Schmidt-Cassegrain telescopes by Celestron came out on the market. Besides, I felt that grinding, polishing and testing a mirror of that size was a bit beyond my abilities at that point. And I knew that would take a lot longer to produce. We also had a very good Byers worm gear and drive that performed almost perfectly. There was a bit of slop in the two axes due to the ball bearing housings being slightly larger than the axes shafts, but I managed to work with it.

I was going to put a shot of my old ATM (Amateur Telescope Making) log book here that I kept as a teenager for grinding telescope mirrors, but it must be packed away somewhere. After all, that was a full 50 years ago now! Just imagine a yellowed page with pencil scribbling of how many hours were spent grinding with various grades of carborundum grit!

Unfortunately, I never did obtain a T adapter for connecting a camera to the eyepiece holder of the telescope. So for years, it was strictly a visual instrument for me. After that, telescopes, astronomy and photography took a backseat to college (albeit a degree in Optics), a family of my own, and life in general.

Another thing that I find a bit funny with life, especially having grown older, is how we tend to circle back and try to find meaning in retrospection. I’m a few years away from retirement now, and moving a bit slower. So with a bit of retrospection in mind, here is a progression over time showing improvement in technique, plus what every photographer knows – more expensive equipment generally means better photos!

The Moon through a standard kit lens on a tripod. ISO 800, 55mm, f16, 1/250 sec.

Now we are getting somewhere. A T-adapter really isn’t very expensive! Through a typical spotting scope of about 500mm focal length. ISO 200, f16, 1/640 sec.

With a 4 1/4″ (114mm) F8 reflector telescope, using eyepiece projection with a 20mm eyepiece for a magnification of 45x. ISO 400, f8, 910mm focal length, 1/60 sec. This was shot about an hour before sunset, hence the blue background.

With a 4 1/4″ (114mm) F8 reflector telescope, using eyepiece projection with a 12mm eyepiece for a magnification of 76x. At this point, I readily see why serious astrophotographers will pay up to a few thousand dollars for a rock-solid mount. I had to set the time delay to 10 seconds; even then it wasn’t totally still. Also, if you zoom in really close, you’ll see chromatic aberration.

Next up, I plan to attach my APSC-sensor DSLR to a 8″ Meade ACF (Advanced Coma-Free) telescope. ACF telescopes use a modified Ritchey-Chrétien optical system to obtain nearly perfect correction of optical aberrations, plus a wider, flatter field.

Looking back, I’m also a bit amazed and very glad that telescopes are more affordable now that back in the late 20th century. Especially when you factor in the amazing computer-assisted capabilities available now, as well as the relative ease of optical manufacturing brought about by computer-aided manufacturing. I suspect this later technology has kept prices of modern Schmidt-Cassegrain and ACF optical systems not much higher than what they were many decades ago.

About Pgibson

I'm from Huntsville, Alabama where I work as a Software Engineer and part-time banjo instructor. My wife Miiko and I worship at Rivertree Downtown. I've been playing various instruments since my teen years. I started mandolin and dulcimer at about age 17 and banjo at 20. I love just about all kinds of music. In terms of banjo styles, I play and teach Scruggs, melodic, clawhammer, and 2-finger styles. I'm also very keen on theology, being a Trail Care Partner with the Land Trust of North Alabama, photography, urban planning, architecture, astronomy, ATM (amateur telescope making), birding, martial arts, and about 30 other distracting hobbies to a (mercifully) lesser extent.
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