A quick M42

[rmuhlack (Richard)]

Has been a few weeks since I've been able to get some clear weather for deep sky imaging. Clouds have come in again tonight, so i thought i'd make the most of the last two nights with an easy bright target.

Star shapes (particularly in the top left) are not perfect. Will address the collimation/tilt issue when I clean the optics over the Christmas break.

19 x 600s
30 x 120s
28 x 30s
(all ISO1600)

Camera is a DIY modified Canon 1000D with regulated cooling at 10C (just above the ambient dew point)

hi res: http://www.astrobin.com/136655/0/

[multiweb (Marc)]

Great close up. Superb details. Can't see the trap. Has it got caught up in a 'fred' filter?

[rmuhlack (Richard)]

Thanks Marc. The Trap is there, but not as well resolved as I would like. I'm thinking I might need to collect some really short exposure frames (say 5s subs) to improve that aspect of the image.

[rustigsmed (Russell)]

that's beautiful Richard.
great work.

Rusty

[nebulosity. (Jo)]

What a fantastic image! Great job

Jo

[Screwdriverone (Chris)]

So very dusty for a dslr image,

Nice work!

Cheers

Chris

[PeterEde (Peter)]

Very nice shots

[alpal]

Hi Richard,
Great picture - at first glance it looked like a CCD image.
I hope you can sort out the collimation issues.
Isn't the native ISO = 800 with a 1000D?
I would have gone for a touch more contrast but that's personal taste.

cheers
Allan

[Ross G]

Hi Richard.

A great looking closeup.

Nice colour.

Ross.

[multiweb (Marc)]

Originally Posted by rmuhlack

Thanks Marc. The Trap is there, but not as well resolved as I would like. I'm thinking I might need to collect some really short exposure frames (say 5s subs) to improve that aspect of the image.

Ha ok, see it now. I think what you're seeing could be the effect of deconvolution when star cores are burnt or over-exposed. CCD Stack in particular will punch out holes in the stars effectively taking them out from the inside out. Just do a quick star mask and put the original stars back on to the old ones.

[RickS (Rick)]

Nice M42, Richard! I agree with Marc that something odd has happened to the stars in the Trap.

Cheers,
Rick.

[cometcatcher (Kevin)]

Beautiful image for a quickie Richard!

[Rex]

Nice one Richard, great detail for a quickie.

[rmuhlack (Richard)]

A clear night last night allowed for capture of another set of short subs (30 x 5sec) to clean up the Trap.

Hi res here: http://www.astrobin.com/full/136655/B/

[rmuhlack (Richard)]

Originally Posted by alpal

Isn't the native ISO = 800 with a 1000D?

According to Roger Clark, unity gain / native ISO etc are "flawed concepts" - see here http://www.clarkvision.com/articles/...ry/#unity_gain

I have conducted my own experiments which seem to indicate that the SNR is indeed higher at ISO1600 than it is at ISO800 (regardless of sub exposure time). With an uncooled camera I found I was limited to subs of about 3-4 minutes before SNR would be unduly affected by thermal noise (eg see here). Now that I have added a cooling mod I can run longer subs if required, with 10mins now being my sub exposure of choice for faint fuzzies.

[SimmoW (SIMON)]

Thats a lovely close up image Richard.

[multiweb (Marc)]

Looks awesome!