Astrophotography & Post-processing images?

[theboyk]

Hello,

I'm new to astrophotography, though a long-time user in regards to digital imaging (colour correction, retouching, colour theory, etc.). Recently I've been experimenting with some astrophotography (mainly, right now, the moon) and I'm wondering if anyone knows of a good resource for information on post-processing of astrophotography images, mainly with regards to RAW images and post-processing in Adobe Photoshop?

Any advice would be appreciated!
Thanks,
Kristin.

[le_R]

have a look on these excellent softwares :
Deepskystacker :easy and user friendly.
Iris : quite hard first, but very powerful.

each of them have good tutorials.

[theboyk]

Thanks (I should have mentioned, I'm a Mac-user). But, helpful none-the-less as I never considered the technique of shooting for stacking. I shoot a lot of HDR (not that cheesy surrealistic style HDR, but very subtle HDR...anyway, off topic) so I'm totally going to play with that next time I shoot!
k.

Originally Posted by le_R

have a look on these excellent softwares :
Deepskystacker :easy and user friendly.
Iris : quite hard first, but very powerful.

each of them have good tutorials.

[Michael_Lambert]

Keep in mind the stacking for astro is not the same as HDR. HDR is different exposures where shooting astro is the same exposure over and over.. Then using the stacking software it helps clean up the image reducing the noise in the shot.

[theboyk]

Originally Posted by Michael_Lambert

Keep in mind the stacking for astro is not the same as HDR. HDR is different exposures where shooting astro is the same exposure over and over.. Then using the stacking software it helps clean up the image reducing the noise in the shot.

Oh! My mistake! I'll have to do more research into the stacking and how that works (I assume different images of the same thing will produce different areas of noise and the application then has an algorithm to find and remove the noise). Anyway, very interesting and requires more research!

Thanks as well!
Kristin.

[Adrena1in]

Originally Posted by theboyk

...(I assume different images of the same thing will produce different areas of noise and the application then has an algorithm to find and remove the noise).

Spot on. Noise between the "light" frames is evened out and removed, and at the same time the data is emphasised. The more frames, the better the result. Along with the "light" frame it's recommended to also take "dark" frames. Same setup, same exposure settings, just with the lens cap on. Stacking these then helps to remove any hot pixels. Finally, "flat" frames are again taken with the same setup, but involve either putting a white t-shirt over the lens and taking a few shots in a lit room, to get a nice even, flat image. Stacking *these* helps remove dust spots and stuff. (At least I think that's all correct.)

I wouldn't worry too much about stacking moon shots though...most decent moon images are single exposures. What equipment are you shooting with? Have you got anything to show us already?

[theboyk]

Originally Posted by Adrena1in

Spot on. Noise between the "light" frames is evened out and removed, and at the same time the data is emphasised. The more frames, the better the result. Along with the "light" frame it's recommended to also take "dark" frames. Same setup, same exposure settings, just with the lens cap on. Stacking these then helps to remove any hot pixels. Finally, "flat" frames are again taken with the same setup, but involve either putting a white t-shirt over the lens and taking a few shots in a lit room, to get a nice even, flat image. Stacking *these* helps remove dust spots and stuff. (At least I think that's all correct.)

I wouldn't worry too much about stacking moon shots though...most decent moon images are single exposures. What equipment are you shooting with? Have you got anything to show us already?

Thanks for the info — that's great! So, the dark frame is with the lens cap on, but the light frame — how do you do that? As for my equipment, I mainly shoot wildlife and nature landscape, but I've posted another thread on that (and you've replied already <G>).

...about equipment suggestions already. I haven't done a lot of astro shooting yet, but plan to get into it (as I find it VERY interested). Right now, it's all about learning/theory at this stage, then, when it's not -25 out at night (ie. in the summer), I'll get out and start experimenting!!!

So, anyone have any suggestions on Mac-based applications for this?

Thanks again!
Kristin.

[Michael_Lambert]

Originally Posted by theboyk

So, anyone have any suggestions on Mac-based applications for this?

Yup - Run Bootcamp and install Windows XP and use the PC based software

Or check out this thread here.

http://www.cloudynights.com/item.php?item_id=1044

[theboyk]

Oh, SNAP!
I guess if I have to... <G>
Thanks Michael!
k.

[Adrena1in]

Originally Posted by theboyk

So, the dark frame is with the lens cap on, but the light frame — how do you do that?

The light frames are your images.