Star Trail Photo (1) And Also A Question About Noise

[jsc230]

Hello all,

This might be my first post in this area of the forum. I took this star trail photo last night at Bear Meadows Natural Area in Rothrock State Forest in PA. I think it turned out okay, I need a better foreground, but this was good enough for a test.

The second photo is a 100% crop of the Luminance Noise that I got from my camera. Is this just because of the long exposure (40 minutes)? Last time I did a star trail I took a lot of 30 second exposures, then combined them in Photoshop. That was was a lot more work but less noise. Is there a good way to do one exposure and avoid this noise? Photoshop's noise reduction ignored it completely.

Thanks,

Joe Conklin

EXIF
Camera: Canon EOS 5D
Lens: 17-40L @ 17mm
Tv: 40 Minutes
Av: f/4.0
ISO: 100

http://farm4.static.flickr.com/3578/3452108965_cc2b4a1f0e_o.jpg

http://farm4.static.flickr.com/3661/3452108581_4739c6d53c_o.jpg

[Nighthound]

Great image Joe.

Unfortunately thermal noise is unavoidable at such a long exposure. It really doesn't look obvious in your final result. Shooting during very cold temps will help reduce the noise some, I much prefer winter for deep sky imaging but winters are a bit less frigid here.

Have you tried a program designed for the short exposure approach you mentioned:
http://www.startrails.de/html/software.html

[Exposure101]

Nice pix!! When taking star trail pix, how can you tell which one is the Polaris?

[jsc230]

Great image Joe.

Have you tried a program designed for the short exposure approach you mentioned:
http://www.startrails.de/html/software.html

I have used that, I was experimenting to see if I can avoid taking 200-300 images (that's a lot of raw files).


Nice pix!! When taking star trail pix, how can you tell which one is the Polaris?


To find polaris look at the big dipper, follow a line from the front 2 stars of the dipper part to polaris. It is about 3 fist widths at arms length away.

Here is a flash animation on how to find polaris http://ecuip.lib.uchicago.edu/diglib/science/cultural_astronomy/interactives/polaris/polaris.swf

Joe Conklin

[Exposure101]

To find polaris look at the big dipper, follow a line from the front 2 stars of the dipper part to polaris. It is about 3 fist widths at arms length away.

Here is a flash animation on how to find polaris http://ecuip.lib.uchicago.edu/diglib/science/cultural_astronomy/interactives/polaris/polaris.swf

Joe Conklin

Thanks for the link! I actually searched and watched that video right after posting the question here. Thanks for clearing that up though!

[Nighthound]

I have used that, I was experimenting to see if I can avoid taking 200-300 images (that's a lot of raw files).

I can certainly understand that. It's enough work stacking 60-70 exposures.

[jamie200]

sorry if i'm hijacking this thread, but i use a Mac for my pp, and CS3. The star trails program only appears to work on a windows PC. Does anyone know of an alternative stacking method I can use?

I've tried taking star trails pics with long exposures, but from all the great images on here, it seems that short and many seems to be the better exposure method


Thanks in advance

[Nighthound]

I haven't seen a dedicated program written for the Mac. I haven't used these actions but I have seen some good results.
http://www.schursastrophotography.com/software/photoshop/startrails.html