M42/M43 from this morning (24th Sep)

[iceman]

Hi all

The sky was clear overnight but transparency was pretty bad. It just wasn't very dark. It was very dewey, too!

I didn't drift align at all, just put the EQ6 down on the pavers where the marks are. This again limited me to 30s exposures. I need to spend some time drift aligning so I can go longer and deeper. I'll go to Dick Smith today and buy some replacement batteries for my illuminated reticle (yes, they're flat again :)).

Saxon ED80 on EQ6 with Canon 350D at prime focus.
21x 30s exposures (added in ImagesPlus) @ ISO1600, ICNR on, mirror lockup on.
Core masked using an average of the 21 exposures, and the trap masked using an average of 3x 10s exposures.

I composed the shot to include the open cluster at the bottom, but it didn't really add anything to the shot. Next time I'll center it on M42 itself.

I think this is better (just slightly) than my first M42, but there's not a lot in it. I need longer exposures, it's as simple as that.

Thanks for looking.

[Omaroo]

Do you have an original-resolution version stored anywhere Mike?

[iceman]

Not yet, Chris. Gimme some time and i'll upload a hi-res shot.

[iceman]

Ok here's the full resolution version. Saved at 10 (out of 12) jpeg quality. 900kb.

M42 full res (http://www.iceinspace.com.au/uploads/20070924-m42-full.jpg)

The full res version shows the flaws much more obviously, including slight trailing on the stars and a noisy background (resulting from adding instead of averaging).

[Omaroo]

Looks great Mike. The high-res file gives much better tonal progression in the nebulous regions - without the banding that compression leaves you with. Very nice indeed! I can't wait to go to Magellan over the LWE and do some of my own now.

Cheers
Chris

[Ric]

A lovely image Mike, very natural looking. I'm looking forward to capturing this region myself with Ha this year.

Cheers

[h0ughy]

nice shot mike - you wont know yourslef once you get the guiding right

[davidpretorius]

nice mike, what do you mean by mirror lock??

[jase]

I don't know Mike. Looks much the same as your other effort. Perhaps use the data from the two sessions to see what you get. Might be marginally better, but you're still dealing with short exposure times so you wont bring out any further nebulosity. You'll simply get a better S/N ratio.

[whmacs]

Nice job Mike. I'm not a really late night person (this questions astronomy as being a suitable hobby!) so I'll have to wait a bit longer before I try my hand at M42.
With a good polar alignment how long can you take an unguided exposure with the EQ6 and 80ED?

Regards,
Stephen

[iceman]

Hi Stephen.
I don't know, because I don't have good polar alignment :)

With bad polar alignment, I can go 30s unguided.