THE EMANCIPATION OF THE URBAN ASTROPHOTOGRAPHER
---------------------------------------------
John Pazmino
NYSkies Astronomy Inc
www.nyskies.org
nyskies@nyskies.org
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 [1984]. 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.