ball head

[Mackaygolspie]

Having now constructed a scotch mount all i need now is a ball head for my camera. Any advise on these would be appreciated.

Also going back to the scotch mount, (this may sound rediculously stupid) but now i can take longer exposures. but how long? i was under the impression that if i took say a 20 minute exposure i would have just a white picture? Not sure i understand.

thanks

[Astrosurf]

Any decent ball head joint, like a Manfrotto, will be fine. I'm sure you will get suggestions soon!

I don't understand the 'white picture' thing either! You will get an orange glow if you have light pollution but that can be sorted with a light pollution filter. 

What camera and lenses will you be using?

Alexxx

[Mackaygolspie]

I'll be using 35mm 1.8. My thoughts were if I'm going to be shooting the sky with my lens wide open for 20mins say, what would my results be? Clear sharp stars or really bright over exposed shot?

[Davey-T]

Most astro photography is a case of suck it and see, a lot depends on sky conditions, start with ISO800 and adjust other stuff until you're happy with the results then don't forget to write them down or you won't remember next time

And don't use the lens wide open, stop it down a bit.

Dave

[RichM63]

On the advice of someone on here I bought this one Ball Head totally delighted I should have bought two.

No expert at all but I wouldn't start at 20mins all you are likely to get at best would be pointless star trails or big circles in the sky, you are going to have to work up to very long exposures.

[Astrosurf]

Yep, start with 30s at 800 ISO, then increase. Then increase the ISO. It depends on the light pollution. If you have that problem, invest in a light pollution filter. I have the Canon Astronomik clip-in one. A bit expensive but very good. But I got mine second hand. Ask about other possibilities.

[wxsatuser]

I'll be using 35mm 1.8. My thoughts were if I'm going to be shooting the sky with my lens wide open for 20mins say, what would my results be? Clear sharp stars or really bright over exposed shot?

For any combination of dslr lens, scope, fstop and ISO, the best way to gauge the correct exposure, for your sky conditions, is with the camera histogram.

Try and get the main histogram peak somewhere in the range of 20 to 40%.

Depending on how bright your sky is and if you use an LP filter this could mean an exposure of anywhere between 30 seconds to 15minutes.

My experience here with my skies, moderate LP, mean I get about 5minutes at f/4 ISO 1600 for a 25% histogram using an Astronomik CLS clip filter.

Sometimes on a really dark night I have pushed this to 10minutes for a 40% histogram.

Here is what the histogram should look like.

This is a ten minute exposure of Andromeda at f/4.5 the histogram peak is at approximately 25%, bottom white luminosity histogram.