Let's Photograph Comet 46P Wirtanen
On Sunday, December 23, 2018 at 4:30:39 PM UTC-8, hleopold wrote:
On Dec 22, 2018, Davoud wrote
(in article ):
...Always a joy to see your photos, David, I look forward to more in the future.
I mostly read here, hardly ever comment. Not to mention I am jealous of your
set-up, though not of your location, as bad as our seeing is here you have
Your words are kinder than I deserve! I have complained here about
Maryland sky conditions from time to time, but not too bitterly, I
hope. I try to take it with equanimity; I get what I get and I try to
make the best I can of it.
As, for the vast majority of us, we all must.
Same for my vision. I am 74 years old and I have macular degeneration.
My corrected vision in my left eye is 20/25, i.e., very good. But over
the past few months I have noted a deterioration in my right eye to the
point where I cannot read with my left eye covered. My ophthalmologist
referred me to an optometrist who specializes in low vision. My right
eye can't be "fixed," but a new pair of glasses, coming in about two
weeks, will help.
Age eventually gets us all, I am only 67, in 3 weeks to be 68, and my eyes
just ain’t what they used to be. Of course in my case I have to go back to
when I was 12 when my eyes went from practically perfect to very near-sighted
and very strong astigmatism in both eyes. Correctable but slowly getting
harder to focus as I age.
Good that I'm not a visual observer; I can still
focus on a laptop display, but faint fuzzies don't work for me in an
eyepiece. I use a Bahtinov mask on my Tak 106
Way back in the late 70s early 80s I did, for a while, try photography with
my scopes, but otherwise I have been strictly a visual observer. I can’t
believe the great stuff that we have these days. I am not really a fan of
digital photography in many ways, I loved shooting film, and that was how I
did astro photos back then. Used a home-brew camera and cut my 35mm film to
single frame. My camera was much like one that was described in Sky and
Telescope back about that time, starting with a short extension tube and
built up the body out of flat sheets of black opaque plastic glued together
to hold the film in place plus a dark slide to take the shot. If was fun, but
fairly frustrating at the same time. At that time I did most of my
photography using B&W film, so I was able to do my own processing. Not really
an easy thing to do on a Navy ship. About once a week I would take over the
head for our dept. berthing area to do processing. Even at night the light
leaks were ridiculous, I used a lot of black tape every time. And hoping like
everything that no one needed to use it for the few minutes while
transferring the exposed film to the tank. Yeah, I did used a changing bag
but you probably know how that works.
These days, though, I just mostly like to look at things through the scope.
Harry F. Leopold
The Prints of Darkness (remove gene to email)
You could have used one of the various methods that I used in my youth which allowed me to use a standard 35mm camera - so I didn't have to cut up individual frames of film.
1) Afocal - focus telescope for visual use, mount camera focused at infinity, then do fine focus with telescope eyepiece.
2) Projection - I experimented a bit with positive projection. That involves just mounting the camera without a lens, then focusing the telescope eyepiece further out to move the primary image to the camera focal plane.
3) Direct Objective - what I finally chose, but it took a lot of work as my telescope was a reflector. I think it would have been even more difficult with a refractor. I had to move the primary mirror forward a bit to make the image plane accessible, use a larger secondary to capture the whole light cone and a larger diameter eyepiece holder(2") to keep the lens tube from blocking some of the cone. This produced by far the brightest and sharpest images. The primary disadvantage was that I needed to use a short extension tube for my eyepieces when doing visual work. But since I had installed a 2" lens holder, I needed an adapter anyway so my 1 1/4" eyepieces would fit..