THE EMANCIPATION OF THE URBAN ASTROPHOTOGRAPHER --------------------------------------------- John Pazmino NYSkies Astronomy Inc www.nyskies.org email@example.com 1984 March 1
My situation is typical of the city astrophotographer. I have no place to set up a conventional astrophotography rig. When my sister lived across the street, I could use her treeless backyard for orthodox star photos, my own yard being tree-choked. My D[ynamax]-8 mount had a bedplate for my 200mm camera lens, giving me quite pleasing deep-sky shots with 60-90 seconds on Fujichrome-100 film. But it took several trips to gather all the parts, an hour to assemble and adjust everything, and careful placement of the mount to maximize sky exposure. When the night's work was done, an equally big chore was vacating the yard. It was only the convenience of stepping across the street that let me go through this rigamarole. In mid-1982, my sister moved to South Carolina, depriving me of that observing spot. Of course, I continue camera-and-tripod work from my house and on travels, being limited to wide-angle shots where star- trailing is not too noticeable. Deep-sky work, however, was totally suspended without the tracking apparatus. Now, the 3M Company markets an ASA 1000 slide film, fully ten times as fast as Fujichrome-100. The November 1983 SKY & TELESCOPE had a most heartening review of this new film's utility for astronomers. Surprisingly, the review referred only to tracking setups, even with wide-angle lenses. I wondered how the 3M-1000 film would serve the camera-and-tripod sector, the confined domain of the average city stargazer with no commodious field for observing. Apparently, the star pictures I once got with a 60-90 second exposure -- while tracking -- I should now get with only 6-9 sec. But with only 6-9 seconds, the stars trail so little that no tracking is necessary. I don't need elaborate clockdrive gear. I should get deep-sky pictures with just my camera-and-tripod. So, over the year-end holidays [of 1983], I found in my betreed yard a spot where the Pleiades peeked between bare branches. with the 200mm lens, I shot a series at 3, 5, 7, and 10 seconds. Then I moved over some to catch the Orion Nebula, and again to get the Double Cluster. In about a half-hour, I photographed ten objects. This included shuffling around to get the objects in clear patches of sky, adjusting the tripod, aiming the camera, and the duration of each shot. When I got the slides back, I was astounded. There were pictures all the equal of my former clockdrive days, and the stars trailed hardly at all. The 10-second shots were actually overexposed by the city airglow. I did, to be frank, catch a bit of roof or twig in a few frames. I was just happy to get the main object in the field. For my second roll, I planned more carefully. I put the tripod in its equatorial stance, and as I moved about the yard I kept the polar axis aimed at Polaris. Also, I now knew that 5-8 seconds yielded the optimum balance between adequate star image density and skyglow. This time, I photographed about fifteen objects, even some I had never before tried, like the clusters in the "W" of Cassiopeia and in the "Trapezoid" of Perseus. The new pictures were, then, portrait or atlas shots with North up and West to the right. Again, trailing was hardly discernible and the new pictures melded nicely into my deep-sky collection. I had taken quite pleasing deep-sky pictures with ordinary camera equipment from a most unpromising observing site. This is a true emancipation of the city observer, an entree' into a pursuit heretofore barred from him, a loosing of the binds of his homestead. Now, a window, terrace, stoop, rooftop, garden, or courtyard are viable sites for astrophotography. Armed with camera and tripod -- packed into a totebag -- and the 3M-l000 film, the city stargazer can spontaneously go to his site, a friend's site, Gateway, or Fieldston. He can more casually use public transit or cabs, or even walk to his observing place. He can repair to the terrace, say, set up the tripod, get his shots, and then turn in for the night within, literally, an hour. To be sure, there's a price to pay. The 3M-l000 costs about $9.50 per 36-exposure roll, with 3M processing, and it's stocked by only the larger photo stores in the City. Also, it's a mite grainier than the common color slide films. Exposures are a little more critical, being so short overall, so you'll have to bracket in the first roll. Another "price" is the ease of overexposure. The City sky will wipe out the stars long before they get any considerable trails. Exposures must be brief. 10 seconds seems to be the ultimate limit in outer Flatbush, Brooklyn, and about 8 seconds is tops in Manhattan's Upper East Side. This "price" seemed wholly insignificant in late January . I stepped outside from my winter roost in Manhattan and photographed M44, M67, and the head of Hydra, with about ten minutes of effort. Previously, I could not even have thought of taking such pictures from a building terrace.