Approve the Cookies
This website uses cookies to improve your user experience. By using this site, you agree to our use of cookies. Read More.
OK
Index  •   • New posts  •   • RTAT  •   • 'Best of'  •   • Gallery  •   • Gear  •   • Reviews
New posts  •   • RTAT  •   • 'Best of'  •   • Gallery  •   • Gear  •   • Reviews
Register to forums    Log in

 
FORUMS Photo Sharing & Visual Enjoyment Astronomy & Celestial
Thread started 16 Aug 2010 (Monday) 02:59
Prev/next
sponsored links
(this ad will go away when you log in as registered member)

Very First Attempt: Night Sky

 
jwcdds
Cream of the Crop
jwcdds's Avatar
Joined Aug 2004
Santa Monica, CA
Aug 16, 2010 02:59 |  #1

I tried my hand at some astrophotography tonight. Certainly less-than-ideal situation (as I'm in the city and talk about light pollution) :lol: Takes a lot of tweaking to even get something remotely acceptable.

4s, f/1.4, is1600, 24mm. (And a whole-lotta-levels tweaking in CS5.)

IMAGE: http://julianchen.smugmug.com/Photography/Astrophotography/201008157565/971402815_wEE54-XL.jpg

I don't know how you more experienced folks do it. I see some people say start with iso1600, f/1.4, and 20s. All I got was nothing but a white, blown-out image. :lol: I need to get out of the city I suppose.

Would've been nice if I had something on the horizon for reference/composition but I was just gunning to capture some stars tonight. This will be a VERY LOONG work-in-progress for me. But I'm eager to learn. :)

Julian
Gear/Feedbacks | SmugMug (external link) | Flickr (external link) | Blog (external link) | Instagram (external link) | YouTube (external link)
My Review | "The Mighty One" (external link)
Founding member and President of the BOGUS Photo Club (Blatantly-Over-Geared & Under-Skilled)

LOG IN TO REPLY
jsigone
Senior Member
416 posts
Joined Apr 2009
Aug 16, 2010 10:46 |  #2

Good start. But you can't really shoot at wide open like that or you'll get allot of curvature in the lens like you did having all the corners blacked out. Generally you need to go 1 to 2 stops down from wide open to flatten out the field/lens. With that lens I'd probably start at F2.8 and see how the corners are. Go up another 1/2s stop and see if the corners don't improve. If they do try another 1/2stop up. You're trying to find the sweet spot of the lens. It could be F2.8 or lower.

If you have allot of light pollution, you can also try to set the CWB on the sky background and see if that helps, You can always change it later on the PC as long as you're shooting raw. If you're using a fixed tripod and the 24mm, you can probably push 20-30 sec subs before you see tailing unless your pixel peeping at 100-200% crop. At that you're not taking the image for whats its worth.

Another trick of the trade is to stack multiple images to bring out the details. Let say you take 30 subs, you ideally want 30-50 % more subs with the lens cap on, these are called darks and when you stack them will cancel the noise out. Deep Sky stacker is a free and easy software to do that.
Here's a good tutorial I found on both DSS and basic PS leveling and curve changes.
http://astrochat.co.uk​/forum/viewtopic.php?t​=13241external link

Enjoy the process and don't be scared to try things, the 7D is turning out to be a great camera for AP, very sensitive sensor and should catch allot of Ha (red) nubulas w/o modding it.


My Flickrexternal link

LOG IN TO REPLY
jwcdds
THREAD ­ STARTER
Cream of the Crop
jwcdds's Avatar
Joined Aug 2004
Santa Monica, CA
Aug 16, 2010 11:22 |  #3

Excellent! Thanks for the tips. I'll look into the DSS tutorial.

On one of my attempts to tweak the photo, I went into "curves" and used the dropper to sample image to set black point. Made everything dark, but also took away what I believe are the fainter stars. We'll see. I'll start w/ f/2.8 and also try to find less light pollution. :D


Julian
Gear/Feedbacks | SmugMug (external link) | Flickr (external link) | Blog (external link) | Instagram (external link) | YouTube (external link)
My Review | "The Mighty One" (external link)
Founding member and President of the BOGUS Photo Club (Blatantly-Over-Geared & Under-Skilled)

LOG IN TO REPLY
jsigone
Senior Member
416 posts
Joined Apr 2009
Aug 16, 2010 12:42 |  #4

Here's another link to help you better understand setting black & white points and where to adjust them in the curve. http://myastroimages.c​om ..._To_Use_PhotoShop_C​urves/external link

But first you need to color balance the histogram using the level slider per color channel. Once RBG is line up you can start to pull the curves to bring out the details without messing up the color balance. Some times it's easier to crop out the center and work from that, that way you're not getting all the black in the histogram from Vignetting.


My Flickrexternal link

LOG IN TO REPLY
SteveInNZ
Goldmember
1,415 posts
Joined Nov 2007
Auckland, New Zealand
Aug 16, 2010 14:22 |  #5

Search out some gradient removal techniques for astronomical images. They're easy and your image should respond well to them. Then you can start on the curves/levels to drag out what's in there.

Steve.


"Treat every photon with respect" - David Malin.

LOG IN TO REPLY

991 views & 0 likes for this thread
Very First Attempt: Night Sky
FORUMS Photo Sharing & Visual Enjoyment Astronomy & Celestial


Not a member yet? Click here to register to the forums.
Registered members get all the features: search, following threads, own gear list and ratings, likes, more forums, private messaging, thread follow, notifications, own gallery, settings, view hosted photos, own reviews and more...


AAA

Send feedback to staff    •   Jump to forum...    •   Rules    •   Index    •   New posts    •   RTAT    •   'Best of'    •   Gallery    •   Gear    •   Reviews    •   Polls

COOKIES DISCLAIMER: This website uses cookies to improve your user experience. By using this site, you agree to our use of cookies. Privacy policy and cookie usage info.

POWERED BY AMASS 1.4version 1.4
made in Finland
by Pekka Saarinen
for photography-on-the.net
Spent 0.00116 for 4 database queries.
PAGE COMPLETED IN 0.01s
Latest registered member is Wanda Donald
777 guests, 413 members online
Simultaneous users record so far is 6430, that happened on Dec 03, 2017