SLR Camera Work...

[AstroDonut]

Should this be in a different section??

I'm familiar (ish) with 'film' long exposures.

I don't have access to developing facilities and would hate to send a film off to high street developers for it to come back with no results.

Also, would a 300mm lens give me decent results??

Has anybody any suggestions/recommendations???

Brian

[astro_dt]

Hi Brian

There a couple of problems here.

If you send film with astrophotographs to the processors their automatic machines may not detect the frame boundaries properly (they look for light and dark). I took a set a while back and asked them to develop but not cut the negatives. The processing was ok but the negatives came back rolled up in the plastic pot and were quite scratched. I was still able to scan the negatives but the scratches showed.

The 300mm lens will limit your exposure unless the mount is tracked, so you need bright objects. The further away from the celestial pole, the increased apparent motion of the stars will show as trails on the negatives. I have some tables on my website that will allow you calculate the exposure based on the position in the sky and the focal length of the lens. 20 secs on Orion with a 50mm lens will give interesting results. But you could be down to less than 10 secs with the 300mm lens. This is ok with digital where you can stack pictures but it will be limited with film.

Hope this helps, don't want to pour too much cold water on the idea. I get a lot out of widefield.

Danny

[Merlin66]

In the good Ol' days, we used 50mm, 135mm and 200mm lenses on the OM1. Under dark skies we could get 20min exposures and capture LOTS of detail. Not sure nowadays what films/ slides are available..

To get over the shop processing issues we used to take a "normal" photo at the front of the sequence; this allowed them to set up the frames etc.

What sort of mounting/ telescope do you have?

A barndoor/ Scotch mount would work well with these lenses; cheap and effective.

[AstroDonut]

I've recently purchased a NexStar 60 SLT with the GoTo mount and the seller kindly gave me spare dovetail mounting bar. I've heard plenty said about the 60mm scope not being very good (ok... useless) for deep sky work and I've had a decent views of the moon the the stock 25mm and 9mm eyepieces. I got the entire setup for just over £50 from Ebay, wanted to see just how useful a GoTo was.

I'd love to be able to purchase a digital slr but credit crunch is biting hard...

I love the trial and error stuff, may contact the local college and see if the guys in the photo department would like to help me.

Hopefully the GoTo mount should help.

What do you guys think?

[beamer3.6m]

I think it could just lead to frustration as you will not know if the image is worth processing and could cost considerable sums for no result.

I would stick to DSLR's.

[Merlin66]

Which SLR camera would you be using?

[AstroDonut]

Was thinking about an Olympus OM10 (unless anybody can suggest a more suitable model)