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JohnH
professor emeritus
Reged: 10/04/05
Posts: 505
Loc: vancouver near the wilds of B...
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I got into astronomy before cameras and when I had cameras, I had already sold the home built Newt (glad you asked: 10" f/5.5 ground to around 1/3 wave. What do you expect from a grade 7 student?) Anyhow, after getting into Contax and Hasselblad, an old friend let me try doing some piggy back shots. The detail visible on Kodachrome 200 with a 200 mm f/2.8 Angineax lens of Orion and the surrounding area is fairly amazing.
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Thierry
sage
Reged: 07/16/05
Posts: 208
Loc: 47°48'N - 03°29'W - south Brit...
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hi again 
long time before i read the complete thread again 
astrophoto is for me, only a way to go in sky's beauties...
if i could, i just have to look in my eyepieces ! sorrily, i have a bad seeing, myop & astigmat, and i've not $xK to buy the best mount+OTA ! here is my interest with astrophoto...
well, when films won't be available anymore, i hope been able to ground a big piece of glass and make my own 16" DOB for direct seeing 
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Thierry
LXD75-SN8"
WO-ZS-66SD
selfmade equatorial mounts
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ClownFish
Post Laureate
Reged: 04/26/05
Posts: 5608
Loc: Islamabad, Pakistan
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In the end it is all about having fun!
And to anwer this thread's main question, yes film will be here for a while. So if you have film equipment, use it. If you have nothing, then the choice is more difficult.
Oh by the way, I have a Minolta Elite 5400 slide scanner - so my investment in film is probably as much as a descent digital SLR. I just ENJOY film - and like I said, that's what counts!
CF
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Learn all about POLAR ALIGNMENT with my Drift Method Tutorial and simulator!! Or visit my Foreign Service Blog!
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D13x3
super member
Reged: 12/30/04
Posts: 101
Loc: Austin, Texas
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Ty... Here comes a dumb question ...
You say, "Until, that is, you want to stack images."
I have been under the impression that in doing digital astrophotography, stacking images is always necessary -- and, a must.
Is it possible to produce good digital images with just one shot and no stacking?
Regards,
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Sam in Austin
2.4" 1956 Unitron (Original owner)
3" Orion on ST/LXD55 Mount (Fun)
10" Meade LXD55-SNT/UHTC (Sold it)
11" Celestron AS-GT/XLT (Sold it)
5" Meade ETX-125AT/UHTC (Love it)
10" LX90-LNT/UHTC (Heaven on Earth)
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Ty Williams
super member
Reged: 05/13/05
Posts: 186
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D13x3, as can be seen from a post of mine from a couple of lines up, you can see I'm far from an expert at this yet. However, I think the answer to your question is sometimes. My understanding is that noise necessitates the stacking of digital images. If you avoid the noise, you avoid the need for stacking. Right now, I'm imaging by using the lowest ISO my camera offers. This increases the number of hot pixels and drastically increases the amp glow. However, both of those problems are removable with dark frame subtraction, which is something any competent lab will be able to do once you explain to them what you want. I can also raise the ISO somewhat, do the dark fram subtraction, and then Noise Ninja what's left (again, totally reasonable to expect a lab to do this). Obviously, this won't let you image something that's 14th magnitude, but I can easily get decent images of M13 and even M57 with this technique. Once I've gotten a good enough polar alignment that I won't be embarassed for you all to see them, I'll show you. That being said, I do intend to get this whole stacking thing figured out.
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Meade 826 8" f/6 Newt
Meade LXD75 Mount with Autostar
EquinoX on MacOS X
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Harry Pulley
professor emeritus
Reged: 08/17/05
Posts: 506
Loc: Guelph, Ontario, Canada
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Quote:
Ty... Here comes a dumb question ...
You say, "Until, that is, you want to stack images."
I have been under the impression that in doing digital astrophotography, stacking images is always necessary -- and, a must.
Is it possible to produce good digital images with just one shot and no stacking?
Regards,
You can get good digital images without stacking, though you'll usually require at least a dark and a flat frame. To get good results with one image you'll require a long exposure, rather than many short ones though even with one long one, digital images still have noise that you don't get with film which is why even a 'stack' or pair of two digital images is generally better as some of the noise is random (others, like read noise, may be non-random but some of it should come out with bias and dark frames).
You can stack film images too but you need a certain amount of time before you have a slide/negative which is dense enough to scan well, unlike digital images where low values can be added as long as there is some signal above the noise.
Harry
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Vixen VC200L/GP/SS2K-PC, Up-Swing for Omcon 308, Glory 7x50mm, Skyline 7x35mm
Canon FD manual focus bodies (AE-1, TX, FTbN), circular fisheye to 300mm lenses
Starlight Xpress MX716 (you will be tempted by the dark side of the force)
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Ty Williams
super member
Reged: 05/13/05
Posts: 186
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The dark frame tames the non-random noise. Noise Ninja is an AWESOME tool that uses some pretty crazy math to determine what random noise from that camera looks like and remove it from the picture. It's pretty crazy how well it works. It was developed for reducing the noise in high ISO shots for pro work down to a saleable level, but it works pretty well for this purpose too.
W.R.T. flats, I'm lucky in that I had to replace my secondary. I selected an oversized mirror that gives me 100% illumination to the corners of my sensor. But don't film users have to worry about flats too?
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Meade 826 8" f/6 Newt
Meade LXD75 Mount with Autostar
EquinoX on MacOS X
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Harry Pulley
professor emeritus
Reged: 08/17/05
Posts: 506
Loc: Guelph, Ontario, Canada
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Film users may have to worry about flats but because of the non-linear nature of film there isn't much you can do about it except in the old days to make a flat from the image you took, do a positive and stack it with the original. You can't take an image of a white wall for a short time and compare it to a sky shot with film like you can with CCD, they just won't match up so technically there aren't flat film frames you can take. You can make masks though either in wet or dry darkrooms to get rid of it.
With slides, of course if you're projecting them then they're raw! No stacking, no nothing, has to look good as shot. IMO, slides are the ultimate photographic medium as there is no hiding behind post processing aside from perhaps pushing the development.
I didn't have to break my secondary. My scope came with a huge one from the factory for very full illumination (100% without reducer, very good with reducer).
Harry
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Vixen VC200L/GP/SS2K-PC, Up-Swing for Omcon 308, Glory 7x50mm, Skyline 7x35mm
Canon FD manual focus bodies (AE-1, TX, FTbN), circular fisheye to 300mm lenses
Starlight Xpress MX716 (you will be tempted by the dark side of the force)
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Ty Williams
super member
Reged: 05/13/05
Posts: 186
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It occurred to me that I used to use something that served the same purpose as a flat. I have and ultra-wide angle lens with a _terrible_ hot spot in the center (really, I suppose it's more precise to say it had horrid fall off). I ended up creating a piece of lith film with a lot of density in the center that reduced as it went out (like a circular gradient in PS). I'd put it between the enlarger lens and the paper to even out hot spot. Total pain in the butt, though not as much so as doing unsharp masking in the darkroom.
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Meade 826 8" f/6 Newt
Meade LXD75 Mount with Autostar
EquinoX on MacOS X
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stevecoe
Reged: 04/24/04
Posts: 2131
Loc: Arizona, USA
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Howdy all;
I have had good luck with Fuji 800 print film. I have been using it for the past several years and I like the speed and small grain for a fast film. The color balance of the Milky Way is excellent with this film. Someone asked about print film and I wanted to jump in and answer that question.
Yes, there are fewer and fewer film astrophotographers around today, but I still enjoy the results I am getting and I think that it would take a digital photographer a lot more time to match the kind of results I am getting. I only am shooting piggyback, but it is enough for me to enjoy.
Some of my shots are posted on the Saguaro Astronomy Club web site at www.saguaroastro.org
Clear Skies to us all;
Steve Coe
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150mm 6" f/8 Celestron Refractor on Sirius Mount
80mmED 3" f/7.5 Orion Refractor
Author "Deep Sky Observing" Springer-Verlag
Author "Nebulae and How to Observe Them" Springer
New Canon Xt astrocamera with Hutech modification
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