How do you photograph a starry sky in detail?

mattd85

mattd85

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Matt
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Hi all,

Can anyone help me with this? I would like to photograph the stars tonight as its a clear sky but i was wondering what or how is best?

Matt
 
i took this picture by placing my camera on something steady looking straight up, remote shutter release to reduce and vibration caused by pressing the shutter.

f11
29mm focal length
25seconds exposure
1600 iso

if you click on the picture again it'll go full size and i was really suprised you can make out the different colours of the stars/nebula/whatever they are!

http://fc01.deviantart.net/fs71/i/2011/274/2/c/the_stars_and_galaxies___by_richardfrost-d4bi7te.jpg

there is a fair bit of noise in the image.
i should have a go with my new camera and see what results i get but im currently lacking transport :|
 
FightingFigure said:
i took this picture by placing my camera on something steady looking straight up, remote shutter release to reduce and vibration caused by pressing the shutter.

f11
29mm focal length
25seconds exposure
1600 iso




there is a fair bit of noise in the image.
i should have a go with my new camera and see what results i get but im currently lacking transport :|
Click to expand...

Why F11??......Try opening the aperture and reduce the ISO.
 
You need a shorter exposure time as their is some elongation of the stars, without a tracking mount any long exposure, particularly at longer focal lengths would be a problem.

Google Barn Door Tracker, and look at some of the links
 
Last edited:
As a rough guide..... If you divide 600 by your focal length you will get an idea of shutter speed before star trailing occurs.
 
Supposedly for full frame you divide 600 by your focal length to get the longest shutter speed you can use without the stars being motion blurred. For APS-C you divide 400 by your focal length.
Then adjust your aperture and ISO for exposure.

So for example if I use a 40D which has an APS-C sensor with a 17-85mm lens set to 17mm I do this:
400/17 = 23.5
So I should be safe using a shutter speed that's 23 seconds or faster before I start getting blurred stars.

Manually focusing using the zoom function in live view is probably the best way to focus if you can find something in the frame that you can see.

To avoid getting any blur from activating the shutter and mirror you can use mirror lock up and either use a remote shutter release or use the timer mode on your camera.

Flicking through my shots I've got one** that's 2", f/2.8, ISO 800 which is maybe a little bit underexposed so something like 10", f/5.6, ISO 800 might be a good place to start.

**I used the stars from that shot in making this composite, you can look at the top part of that image (the stars) to get an idea of what exposure I was getting with 2", f/2.8, ISO 800.
 
Great info guys, it was a bit to cold tonight i kept steaming the lenses up with my breath.

I will try again tomorrow.

DazJW thats a great picture.

MATT
 
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