My First Astrophoto

austinstkong (Austin) · #1 21-07-2010, 05:50 PM

I actually took this picture shortly after I got my DSLR and before I got serious about astronomy and knew about imaging stacking.

Well anyway, I have a few questions regarding the image:

First, there are a few random red spots on the image (Not really clear on the low res image) Is it due to noise, camera defect or some other reason? They also appear in roughly the same place in other of my nightscene/astro photos.

Second, there is a pale yellowish smear near the right edge of the image, could that be Omega Centauri and a blur lower left of Beta Cruxis is the Jewel Box?

And finally, I had the image shot in manual mode so what do you think of the settings I have used? Of a few I have taken with some different settings, appears to be the best.

And plus any further general advice?

Image Info
Canon EOS 450D
ISO1600
F/4
Single image, 13sec exposure
Hires link
Edit: image got compressed also, so the red spots arent quite visible either and can't seem to be able to upload a high res one. Added a enlarged and cropped one

Thanks

Visionoz (Bill) · #2 21-07-2010, 06:19 PM

Hi Austin

Looks like "hot pixels" inherent in the CMOS sensor if you are getting these on most of your shots, just MHO but others more knowledgeable will chime in for sure

HTH
Cheers
Bill

Quote:

Originally Posted by austinstkong

... First, there are a few random red spots on the image (Not really clear on the low res image) Is it due to noise, camera defect or some other reason? They also appear in roughly the same place in other of my nightscene/astro photos.

adman (Adam) · #3 21-07-2010, 07:22 PM

I think omega centauri would be just out of the frame in the upper right..

Adam

austinstkong (Austin) · #4 21-07-2010, 08:20 PM

Quote:

Originally Posted by adman

I think omega centauri would be just out of the frame in the upper right..

Adam

Not sure it it will make difference but, I meant far right insead of the image instead of top (this image isn't rotated, the one I viewed was)

Rockah (Zal) · #5 21-07-2010, 08:31 PM

Hey Austin

I've got a 500d and I also get the same red dot/s in long exposures. I believe they're just hot pixels which can theoretically be removed manually using an image editing program like photoshop, or get dark frames for your stacks. What I find interesting is I don't get the same red dot in my RAW files that I get in my JPEGs

Bolts_Tweed (Mark) · #6 21-07-2010, 08:59 PM

Gday Mate

Congratulations

FYI - I've orientated the image to make it more visible but Omega is upper left circle and Jewel box is lower right circle.

Have fun in the new hobby

Mark Bolton

adman (Adam) · #7 21-07-2010, 09:54 PM

Yeah - sorry about that. I looked at the attachment on my iPad which cut it off - it downloads the whole image, but doesn't let you scroll in the webpage for some reason....it shows up nicely in the rotated image Mark posted.

Adam

mithrandir (Andrew) · #8 22-07-2010, 08:29 AM

Quote:

Originally Posted by Bolts_Tweed

FYI - I've orientated the image to make it more visible but Omega is upper left circle and Jewel box is lower right circle.

And here is a complete run down on all the objects in the frame (SAO and NGC catalogs). Some may not be immediately obvious, but that's where they are.

luigi · #9 22-07-2010, 09:25 AM

Very nice first image!! I recomend you Topaz Denoise4 to get rid of noise! You can also increase contrast a little me thinks.

Quote:

Originally Posted by mithrandir

And here is a complete run down on all the objects in the frame (SAO and NGC catalogs). Some may not be immediately obvious, but that's where they are.

How did you do this?

mithrandir (Andrew) · #10 22-07-2010, 11:28 AM

Quote:

Originally Posted by luigi

How did you do this?

unimap. See this thread: http://www.iceinspace.com.au/forum/s...ad.php?t=54287

I have another version of this using the Tycho catalogs.

renormalised (Carl) · #11 22-07-2010, 01:12 PM

Nice shot

Try for a 20-30 sec exposure and take about 5-10 for stacking

See what you get

Those red spots are what some have said....hot pixels.

You could also try lowering the ISO rating to 800...your piccie won't be so grainy.

What would also help you is to get a (relatively) cheap EQ mount, like an EQ3 Pro, which will be more than sufficient to heft a camera and lens. With a setup like that, if you polar align the mount reasonably well, you'll be able to take pics lasting minutes instead of seconds and they'll turn out much better

austinstkong (Austin) · #12 22-07-2010, 09:44 PM

Quote:

Originally Posted by mithrandir

And here is a complete run down on all the objects in the frame (SAO and NGC catalogs). Some may not be immediately obvious, but that's where they are.

Quote:

Originally Posted by mithrandir

unimap. See this thread: http://www.iceinspace.com.au/forum/s...ad.php?t=54287

I have another version of this using the Tycho catalogs, but it is at home.

Awesome, nice software. I'm going to try give it a try with later pictures.

Quote:

Originally Posted by luigi

Very nice first image!! I recomend you Topaz Denoise4 to get rid of noise! You can also increase contrast a little me thinks.

Thanks

Quote:

Originally Posted by renormalised

Nice shot

Try for a 20-30 sec exposure and take about 5-10 for stacking

See what you get

Those red spots are what some have said....hot pixels.

You could also try lowering the ISO rating to 800...your piccie won't be so grainy.

What would also help you is to get a (relatively) cheap EQ mount, like an EQ3 Pro, which will be more than sufficient to heft a camera and lens. With a setup like that, if you polar align the mount reasonably well, you'll be able to take pics lasting minutes instead of seconds and they'll turn out much better

Hot pixles.. I see

I might try and take a similar photo again try stacking and see how it goes.
How much am I looking at for an EQ3 Pro?

Thanks again