M42 with Auto Goto Dob

[von Tom]

Hi all,
I starting posting in Ice In Space over at the Solar System images thread and thought I'd say "hi" to you guys here.

I am trying my hand with deepsky photography with my 12" f/5 AutoGoto Skywatcher Dobsonian and Canon EOS 550D at prime focus. Here's an image of M42 from last night at moonrise.

9x 8 sec exposures at 3200 ISO stacked in Registax. Field rotation is evident at the edges, but not apparent in the individual exposures. DeepSkyStacker will correct that when I get the chance to process it that way I will post the results.

Thanks for looking,

Tom

[Jen]

:thumbsup: nice pic Tom :thumbsup: i was wondering what sort of pictures the goto dob would produce :rolleyes: thanks for sharing :thumbsup:

[mswhin63]

Tom, very nice image, try take 20 exposures especially at that ISO. Also some darks etc to really bring out the detail.

If you can extend to 15 seconds would be great. I don't think this is field rotation as I get this myself with my DOB. This is Coma and the only way to correct this is a Coma corrector.

[von Tom]

Thanks Jen and Malcom.

Funnily enough I did take 20 exposures but used only 9 for Registax because of the field rotation. There is coma too! : ) I limited the exposures to 8 seconds because the tracking is accurate but fairly imprecise on the Auto Goto Dob - it wanders and corrects itself at times with minor jerks, leaving trailed images. This was shot in suburban Brisbane, under a bright streetlight with the open tube assembly - obviously not the best of conditions at all but it does show what the scope can do.

Here is the 20 exposures stacked in DeepSkyStacker.

Cheers,

Tom

[telecasterguru]

Good start Tom. Keep on working at it and lengthen the exposures.

[Mighty_oz]

Nice, have u seen kinetic (Steve) (http://www.iceinspace.com.au/forum/member.php?u=5173)'s fantastic images ? U should be able to so something similar, maybe if u stack more and shorten the exposure a little to reduce the field rotation ? Hope to see more of this .

[von Tom]

Thanks guys,

Steve does have great images. The main limitations (apart from my own skill level!) of using a Goto Dobsonian for deepsky imaging is field rotation during each exposure and the precision of the Alt/Az tracking. Both of these affect maximum exposure time which varies depending upon where the object is located in the sky.

I have put up a set of images done with the Sky-Watcher 12" Auto Goto (since I got it 2 months ago) and Canon EOS 550D here: http://www.flickr.com/photos/vontom/sets/72157625885306790/

It includes a shot of 47 Tucanae and the Tarantula Nebula, as well as some Lunar and planetary images.

Cheers,
Tom

[Jen]

:thumbsup: cool Tom the pics come up pretty good with that scope cheers :D