Astrophotography

[ColdEye]

Hello folks, I have been recently dabbling in Wide Field astros and as I was going through Google reading some literature about it, I noticed that there were some pretty cool astro photographs made with film. They were mostly made with short tele or tele lenses and the camera was on a tracking mount. Now I was wondering, what film would be the best to use today? I am only looking for fresh film that I can buy now. I already have the camera and lens, and the tracking mount I will get in a month or so. I am thinking 35mm would be the best option here, as MF seems too bulky for this endeavor. All advice is welcome specially from those who have tried this. Thank you.

 

[pthornto]

Probably Fuji Acros 100...even though it is a 100 speed film it has apparently really great reciprocity characteristics, so will end up being faster than a traditional 400 speed film like tri-x after a few seconds exposure. Probably other modern t-grain films would also be good in this regard.

 

[Nodda Duma]

You'd want to hypersensitize Acros 100 to get enough sensitivity for "reasonable" exposure times.

Do an Internet search and you'll find some info. Sadly, you're about 15 years late on film astrophotography.

 

[Dali]

B&W or color?

 

[LJH]

I hate to write it, but this is one aspect of photography where believe that digital cannot be beaten (well, for the normal photographer, rather than the astrophotographer with altitude and $$ behind them)...

The quality of images that full size sensors at high ISO with ultra wide angle, fast lenses can produce is simply unable to be replicated by using standard equipment/techniques.

Again, I hate to write this...

 

[konakoa]

I've been making wide field astrophotographs for some years now. My work is primarily in b&w. Fuji Acros is your best bet for this. For color Provia worked well for me. Medium format is bulky you say? The astrophotography work I do is in 4x5. Never say never!

Fuji Acros and old Kodak E100G examples below. Straight scans, no manipulation. I don't have a scanned example but Provia will have the same look for color astrophotography.

 

[RobC]

Ahem, if you are using a motorised tracking mount setup correctly then you can use exposures as long as you want. So Any film you like and for astrophotography the highest resolution film you can find. Maybe Adox CMS 20.
However, if you don't have a tracking mount then it depends what you're trying to do. If you are looking for star trails then any slow BW film will do. If you want straight star constealltions then you will need a fast film.

Do the maths, the world rotates 360 degrees in 24 hours. Thats 1 degree every 4 minutes. A short tele of say 135mm has a field of view of around 15deg. So whatever your photographing in the sky will take around 16 minutes to pass across the horizontal of your frame.
If you assume 200 lp/mm resolution on film that is 7200 across the horizontal. To minimise movement to =< 1 lp during exposure then its (16*60)/7200 = 0.13 seconds. So you will want an exposure time of 1/30 or faster a second to get a really sharp image with a 135mm lens. So you're going to need a lens with aperture and probably a 400 speeed film.

Someone please check my maths.

note: Acros gives 200lp/mm at 1000:1 contrast ratio. A star against black sky will probably give you that contrast ratio but I'm guessing that.

 

[Nodda Duma]

RobC, I have to disagree. I think you assume that astrophotography is just about taking star pics. Star pictures is like beginner astrophotography...analogous to point and click photos . The real prize is images of nebulae and galaxies.

Objects in the sky (not stars) are so dim that many films will not respond to the very small number of photons striking the film from objects of interest before the background light, ie "Sky fog" dominates and fogs up your film. This is well-known in the astrophotography world. The other issue is that many films are not sensitive to hydrogen emission line in the deep red that is prevalent in nebulae. Of those films that are, very few have or had suitable reciprocity and/or will survive hypersensitizing for astrophotography. Even in the days before digital imaging.

 

[RobC]

RobC, I have to disagree. I think you assume that astrophotography is just about taking star pics. Star pictures is like beginner astrophotography...analogous to point and click photos . The real prize is images of nebulae and galaxies.

Objects in the sky (not stars) are so dim that many films will not respond to the very small number of photons striking the film from objects of interest before the background light, ie "Sky fog" dominates and fogs up your film. This is well-known in the astrophotography world. The other issue is that many films are not sensitive to hydrogen emission line in the deep red that is prevalent in nebulae. Of those films that are, very few have or had suitable reciprocity and/or will survive hypersensitizing for astrophotography. Even in the days before digital imaging.

Yeah I know nebulae etc are what serious astro photographers want. But OP said wide field and was looking at short tele lenses I think. Obviously the longer focal length the shorter the exposure time required is required due to planet rotation unless you have a motorised tracking mount.

And yes I realise digital is the better option these days but the OP asked about film and it IS and has always has been a possibility if you get it right.

 

[ColdEye]

Thank you for all the replies! From what I have gathered, I think I will experiment with 35mm E-6 and portra 400 for this. I know this might be a late time since a lot of the faster films have been discontonued, but I will be using an iOptron skytracker so I guess that will offset the slow speed films a bit. Also I found a film section over at Cloudy Nights if anyone is interested.

http://www.cloudynights.com/forum/75-film-astrophotography/

I have a few more months to prepare for this, thanks all and keep shooting!