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Matty P
22-04-2008, 09:36 PM
I captured some images yesterday under a dominating full Moon. Nothing special just trying to improve my imaging and processing skills.

I tried a couple of longer exposures as some people suggested. As a result field rotation and star trails started to appear. So I returned back to 30 second exposures. I found out that trying to image with a Alt-Az mount creates more frustration than fast moving clouds. :lol:

All taken with my Celestron 8SE on a Alt-Az mount and Canon 450D with ICNR on. Stacked in DSS and processed with PS CS3.

1. Eta Carinae - 4 x 30 second exposures

2. M20 Triffid Nebula - 2 x 30 second exposures

3. M8 Lagoon Nebula - 1 x 30 second exposure.

In my opinion the images look over processed.

:)
Ric
22-04-2008, 09:58 PM
Hi Matty, your images look great but I think you need to take more exposures and stack them. I do realise though that you are still experimenting.

I have always found if imaging in Alt/Az the golden rule is to keep below 30 seconds and take lots of them. As a rule with my DSI the minimum is usually around 100 subs.

Cheers
Matty P
22-04-2008, 10:07 PM
Thanks Ric,

At this stage I'm spending most of my time experimenting with the camera. I find that out of ten 30 second images only 2 or 3 are suitable for stacking due to bad tracking etc.

I will next time try to capture a lot more subs to stack.

:thumbsup:
Matty P
23-04-2008, 11:38 AM
Just a question,

Because 30 seconds is not a long time to capture a lot of photons what ISO setting should I be using?
renormalised
23-04-2008, 12:24 PM
Matty, you want to invest yourself in a field derotator. I think the Meade one will fit a Celestron scope. It'll get rid of the pesky rotation for you. You could also get yourself a CCD camera like the DSI II or III-pro. If I remember correctly, you can eliminate the field rotation in these by guiding off of two stars in the FoV. It has software to do so. Best to goto the Meade site and find out.

As far as ISO goes, using 30sec exposures I would push the ISO rating out to 800-1600, at least.
Garyh
23-04-2008, 02:02 PM
Not bad at all considering only 30sec subs! :thumbsup: