At no time was it possible for me to consider astrophotography with a telephoto lens or small telescope due to the slow films available, my lack of experience, and my lack of an adequate telescope to track a celestial object long enough (30-60 minutes) to produce a useful picture. I owned a Dynascope 4-inch reflector and later a Cave Astrola 10-inch reflector. They were wonderful visual telescopes but with my minimal mechanical skills, I could not adapt them for long exposure pictures.

By the 1970’s and 1980’s, color film had increased in speed and efficiency and cold cameras and film hypersensitization had been introduced so that it was practical for amateurs to consider long guided exposures of faint celestial objects through telescopes. It was now also possible to take a one-minute exposure on ISO 400 color film with a camera and wide angle lens mounted on a tripod to get an excellent color view of the night sky:

January 1984. All the Planets and Moon were visible in the same quadrant of the sky. Sixty-second exposure with a 17mm f/4 lens on Ektachrome 400 film. T Hunter.

Celestron and later Meade introduced compact, relatively high quality Schmidt Cassegrain telescopes in the 8 to 14-inch size. Their optics and mountings were good enough that successful amateur deep-sky color astrophotography became widespread, though it was not easy, and only the most dedicated and skilled observers obtained good results.

By this time, I was the owner of an observatory with a 24-inch f/5 Newtonian reflector permanently mounted in a dark-sky location (Grasslands Observatory). Now, long exposure telescope prime focus astrophotography was in my grasp. The pictures I produced weren’t great, but at least the objects I photographed were recognizable.

However, I often spent an entire night taking multiple exposures only to be disappointed by my results the next day after I had the film developed at a one-hour photo shop. Sometimes, I forgot to wind the film in the camera and ended up with no pictures whatsoever (Hunter, 1986). At other times, the telescope tracking was terrible, and all I got was gibberish. Sometimes, the images were underexposed or ruined by scratches on the negatives. Often, there was an unpleasant color shift, and I ended up with a green sky background, or I had bad star trailing and everything was out of focus.

My film astrophotography career peaked in 1988 when Dan Knauss and I completed a photographic Messier Marathon using the 24-inch f/5 telescope at the Grasslands Observatory and hypersensitized Konica SR-V 3200 print film. In one night’s effort, we obtained recognizable pictures of approximately 80 Messier Objects. Some of the pictures were fairly good, while others suffered from poor tracking, underexposure, poor focus, and static electricity marks.

The Present – The Digital Darkroom and Why I No Longer Like Film

For me, CCD’s replaced film astrophotography around 2004:

Tri-color (R,V, B) CCD three image montage of the Double Cluster (NGC884/869) taken at the prime focus of a 24-inch f/5 telescope. T. Hunter and J. McGaha, 2004.

I don’t like film, because it is slow compared to digital imaging, the results are not instantaneous, and to a certain extent, they are dependent on whoever develops and prints the film. Anyway, hardly anyone uses film anymore for astronomical imaging. Film is also not much used for every day photography. The modern films are better than ever, but technology has moved on.

CCD cameras give instant feedback, and poor images can be corrected in real-time. Much fainter magnitudes can be reached with CCD imaging, and scientific work is easier to perform on the digital data from a CCD camera. I no longer have to take negatives or slides to a lab for processing or enlarging. I no longer have to worry about reciprocity failure (the tendency of many films to actually become less sensitive to light with longer exposures). Any color or cosmetic problems with my CCD images can often be easily corrected by computer manipulation.

For me, there is no reason to have a darkroom. Nowadays, I use a digital darkroom – my computer and my color printer.

The Future – Single Lens Reflex Digital Cameras (DSLR); Web Cams

Digital cameras and web cams were rapidly accepted by amateur astronomers. My digital Nikon D100 DSLR camera set at ISO 800-1600 years ago became the mainstay of my telephoto imaging for large scale sky pictures:

The Winter Milky Way and Canopus. Sixty-second exposure with an 8mm f/3.5 lens and a Nikon D100 digital camera set to ISO 1600. T. Hunter, 2004.

The results from this camera are instantaneous and can be corrected on the spot with subsequent adjusted exposures or saved for later digital image processing. Wally Palcholka, a world recognized photographer of the night sky, switched to a digital single lens camera for much of his nighttime photography in 2004 (Palcholka, 2004). My Nikon D100 keeps on going, and I love it. It is a dinosaur and has been surpassed by more modern DSLR cameras designed for the astrophotographer - the Canon 20Da and the Canon 60Da as well as large format digital cameras specifically modified for astrophotographic uses.

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