4x5 Astrophotography?

[neutronman]

Howdy all,

I currently use cooled CCD cameras and DSLR's for my astrophotography, but have recently been very curious about trying a 4x5 film camera for some widefield work. I have shot 35mm film and have some limited darkroom experience (many years ago), but I know nothing about the 4x5 format.

I am looking for any information about the step-by-step work flow of this format, and any particulars regarding its use in astrophotography (i.e. I have heard about vacuum backs to keep the film flat, etc.).

Any pointers and/or links to appropriate sites are greatly appreciated -- thanks!

JOhn

[memorris]

I started here: http://www.largeformatphotography.info/

[rugenius]

There are simple techniques that can be applied.
These incorporate purely "wide field" photography using camera + lens + Eq mount + patience...
Beautiful results can be had.
To make them more elaborate, you will need to customize the set-up to involve a filter wheel and precision focuser.
If you want to incorporate any film format to a telescopic instrument... The first thing you have to ask yourself is what Telescope system are you planning on using. I had a 14.5" f/3.3 custom Newt that only provided a 35mm "full frame" usable image circle.
You will have to use a corrector to keep Coma at a minimum along the periphery. The off-axis spot size variation is a huge limitation for larger image formats, as is the need for incredibly fast optics.
The Schmidt camera would be an option. These are NON-VISUAL instruments specifically for photography/imaging.
If you are serious about this effort, contact Phillpp:
http://www.astrooptik.com/



Good luck,
Bill

[neutronman]

Thanks guys.

Bill -- I currently use a Takahashi FSQ-106ED scope on an EM-200 Equatorial mount. My plan was to have the FSQ do guide exposures, while letting a 4x5 camera ride piggyback with a wide field lens. At least that's my plan

JOhn

[rdenney]

While I wouldn't want to be the voice of discouragement, I can't help but offer the following advice:

Master astrophotography using film in a smaller camera before trying to do it in a large-format camera. You know the old saying for those who grind their own mirrors: If you want to grind a 12" mirror, grind a 6" mirror first.

Once you are comfortable with dealing with film, then consider dealing with big film.

Rick "thinking an old mechanical 35mm camera, loaded with, say, Provia, and a 135mm lens sounds about right" Denney

[George Stewart]

I have an Astro-Physics 105 f/6 with 600E mount, and have had an 8x10 camera on it. This was/is not a practical solution. While it might be cool, better results can be had from stitching digital images, especially since the sky is effectively static. My first LF camera was an 8x10 astro-camera that I made myself. I took a few terrible images with it and retired to MF astrophotography.

I'd recommend a MF CCD camera designed for astrophotography, and a battery of MF lenses which can be had inexpensively today. The single image quality from it will exceed that from 4x5. Your refractor with such a CCD (MF) and a few stitched images will have better quality than professional LF astronomy plates from just a few decades ago.

[bvstaples]

I too am pursuing astrophotography with a 4x5, and eventually with an 8x10. I'm still in the planning stages. Since there's not really a scope that would allow a large enough image circle, it will be wide-field via piggy back. Here's my "basic" plan:

1) Mount my monorail piggyback to a OTA, which will be used as a guidescope.

2) Shoot widefield (probably with a 210 Fujinon at f/5.6) onto 400 speed B&W, to test the system and exposures.

3) Once guiding and exposure calculations are set, try other films (I'm thinking Provia, and I have a supply of Tech Pan that I will shoot tri-color with filters).

I plan on being at the observatory in mid-October, so check back and I'll let kou know how this works out.

Brian

[Drew Bedo]

What about building a camera based on a Fotoman? It would be rigid and set at infinity. Because it is a modular system,later on, it could be adapted to a larger telescope.

[neutronman]

Thanks for the feedback. Well, maybe I am being a bit optimistic about my prospects for success. I do indeed have no complaints about my SBIG STL-11000M camera for shooting prime focus with the FSQ. It is a dynamite combo. Also, that little modded Canon XSI is a humdinger for going "light". But I have seen some wide field film shots that I thought looked VERY nice, hence my interest in 4X5.

I would love to see any examples you guys have tried/seen.

Brian -- you are doing EXACTLY what I was considering. Perhaps I should wait and see how you do Good luck!

JOhn

[John Jarosz]

Check out Cloudy Nights This link takes you to the film astrophotography section. Very knowledgeable group.

Also google "barn door mount" to see how to mount the camera so it will track the sky motion.

John