Widefield Advice?

[Astrosurf]

Hi all,

I posted this in the Widefield section but no-one's answered yet so I thought I'd post it here too!

I had a go at taking snaps of the constellations tonight but wasn't all that successful. There is some light pollution here which doesn't help.

My camera is a Canon EOS 40D with a zoom lens that came with the camera. I don't think it's that good.

Camera settings: ISO 800, F4 (lowest it would go), lens at infinity.

I took pics of about 10-15 seconds but did try longer and shorter. The pic of Auriga was 10 secs (I think!) and Orion was 5 secs. For Auriga I zoomed in a bit.

Problems: there is some flaring to one side of the stars and I couldn't get the camera to focus that well even with moving the focusing a bit away from full infinity. I've cropped Auriga so you can see the flaring more easily.

Can you guys help me here?!

Alexxx

[Astrosurf]

Is there anyone who can help? Or maybe the pics are OK and the flaring is usual!

[themos]

Alex, to test the optics, shoot towards the North Star Polaris. The stars there don't appear to move much, allowing you to expose longer and test the quality of the images all over the field.

[themos]

Yes, and try an f/8 and an f/4 shot to compare.

[ollypenrice]

I shot Orion in 5 min subs without flaring on the cheapo lens that came with my 1000D. See what happens when you follow Themos's good advice.

Olly

[jgs001]

I thought I'd replied... that's the 17-85 lens isn't it Alex ? Make sure you have the IS turned off (I'm sure it is... but..) it'll cause all sorts of oddities if it's not... it gets very confused with a longer exposure on a tripod trying to cater for movement that isn't there. I'm sure the 40d has liveview, so you can use that at 10x to help sort focus out. And also you can push the ISO up, I'm sure the 40d has better noise handling than the consumer models. Other than that, try what Themos said.

[greenkat]

Hi Alex

Just had a play with your Orion pic, doesnt look too bad.

Could it be a little bit of camera shake from the mirror flipping up?

Do you have mirror lockup ?

I noticed I got a bit of camera shake at very short exposures, longer exposures seemed to get rid of it . Try exposing for 20 seconds & see what you get

Greenkat

[Astrosurf]

Thanks guys. I found when it got to 15 secs I started to get star trailling so I don't know how to get 5mins subs without mounting on a scope or Astrotrac! I'll try again this evening.