DS Astrophotography advise from a newbie

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Kaustav
Posts: 214
Joined: Fri Dec 03, 2004 3:24 pm
Location: London, UK
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DS Astrophotography advise from a newbie

Post by Kaustav »

Image
M13 (click on picture for larger version)

Image
M35 (click on picture for larger version)

I've just started to do some DS imaging and started off with M13 and M35. Here's what I did:
  • - 5x light frame subs, 30 seconds each at ISO 800
    - stacked in Deepsky Stacker
    - adjustment of black point made in Photoshop.
Here's what I used:
  • - William Optics Megrez 110mm
    - Canon 350D (unmodified) at prime focus, snapping in RAW mode.
Here's what I intend to do the next time I image anything like the above:
  • - take at least 10 or 20 subs of the object for one minute each (using auto guiding)
    - take dark, flat and bias frames. Ensuring that I take multiple dark frames, each one the exposed for the same one minute duration as the light frame and stack them before I subtract the dark from the light.
    - try out ISO1600 instead of ISO800.
Since I'm a newbie to this game of DS astrophotography, and since I know there are experts on here with years more experience, I have a few questions for you:
  • - What's the best ISO to use on the Canon 350D when photographing globulars, nebulae and galaxies?
    - Does the ISO requirements vary depending on what filter you might be using?
    - For each object type, i.e. galaxy, nebulae, globular, does the number of subs you take vary? i.e. should I really be taking more subs for galaxies compared to fewer subs for globs?
    - I am badly stuck on how to process these images properly after I've stacked them. I currently don't use any filters, although I will get the CLS filter that fits in to my Canon soon. So for now I have to contend with a lot of LP. If Photoshop CS4 is my processing tool of choice so how do I use it to suppress the LP and bring out the detail in my images? Is there any online tutorial for this? FITS Liberator isn't compatible with CS4 yet :-(
Kaustav Bhattacharya
>> http://kaustav.uk.com/unisphere/ - An online magazine about Astronomy, Science, Social Media and Society.
>> Follow me on Twitter @jupiterorbit
Kaustav
Posts: 214
Joined: Fri Dec 03, 2004 3:24 pm
Location: London, UK
Contact:

Improvements

Post by Kaustav »

Some helpful folks over at another forum gave me some top tips in image processing and so my second attempt at imaging using long exposure on my Canon 350D (without any LP filters) came out rather better. Here are some examples. Click the images for bigger versions:

M82
Image
Click the image above for larger version.

M81
Image
Click the image above for larger version.
Kaustav Bhattacharya
>> http://kaustav.uk.com/unisphere/ - An online magazine about Astronomy, Science, Social Media and Society.
>> Follow me on Twitter @jupiterorbit
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