NGC3576 and company

[Peter Ward]

I reconfigured the RC16 to F 6.0 and managed to grab 3 hours worth on this
last night.

Also attached is a Pixinsight aberration inspector look at the centre and extreme corners of the frame.

Very pleased with the results so far

[SimmoW]

Nice Peter, I see a teensy bit of elongation in the top left but the rest, perfect!

[Peter Ward]

CCDinspector tells me there is a 0.3px X and 0.1px Y tilt @ 162 degrees

....humm... 3 microns....might have to live with it :D

[marc4darkskies]

No comment till I see a bigger version! :P :) Frame edges look pretty good though (assuming they are full res(??)

[Peter Ward]

:lol:

Here you go (http://www.atscope.com.au/BRO/gallery426.html)

[Placidus]

What we like is the superb contrast, especially in the fine serpiginous dust lanes. Don't know how you do it. Sacrificing virtual sea-goats by moonlight perhaps.

[Atmos]

Stars look better in your AP130, tisk tisk :lol:

Looks really good Peter, adding some RGB will be excellent! Although I can’t say I’ve ever been a big fan of this region in RGB.

[marc4darkskies]

Ah yes! Very nice result indeed Peter! :thumbsup: Perfect framing and love the structure you've managed to show! Star shapes are impressively close to perfect at the edges as well.

Colour soon?

[Peter Ward]

Ta Marcus....colour...well, yes! But about the weather :sadeyes:


Shun the non-believer. RGB will be wonderful. :)



No. No goats... sea-worthy or otherwise

Also, I am hoping german engineering will explain the lack of goats around here. :)

[OzEclipse]

Very nice Peter! :thumbsup:

[Joshua Bunn]

Got to be happy with that Peter. A wicked image aswell!

Josh

[Peter Ward]

Thanks Joe, Josh. :)

[Stevec35]

Always extremely impressed by the images you get from the Alluna Peter and this is no exception.

Steve

[alocky]

Getting an effective f6 out of an RC design with that kind of result is another level of special. What a superb piece of optical design! What's the illumination like across the field?
cheers,
Andrew.

[Peter Ward]

Ta Steve...your sublime ion-milled efforts have been exceptional as well :thumbsup:



To be sure, the reducer/corrector is not cheap. But vignetting is minimal and I'm sure the correction is perfect...but my slack-a$$ is not too interested in chasing cause of the residual error at the moment :)

I did seriously consider the Planewave17...a fine instrument, but vignetting was surprisingly strong, it had a larger secondary, Zerodur was not an option and the optics required ultra-terse focal plane spacing...which would have meant many expensive custom adapters.

What you see in this image was literally performance out of the box. Just attached the camera, focused, and hit go to 18x 10 minute subs.

[alpal]

Hi Peter,
that's a superb picture at high res.

"vignetting is minimal?"

I dunno.
It seems to be a fair bit darker in all of the 4 corners.
I don't know if it's real or not.
Did you use flat frames in the stack?

cheers
Allan

[Peter Ward]

Yes.
Flats are mandatory in my neck of the woods....as per the attached sky flat...which shows: stars, dust motes, some vignetting...but hardly a tragedy :)

When calibrated, the h-alpha sky really is darker further from the nebula

:thumbsup:

[alpal]

Fair enough Peter,
it really is darker in the corners.
Well done.

cheers
Allan

[Peter Ward]

Ta...a work in progress...that said, I found where I misplaced the h-alpha flats Re-calibrated and re-stacked....looks cleaner now (same URL)

[alpal]

Hi Peter,
It looks great.
You must be getting good FWHM values -
let me guess - under 2 arc seconds?

cheers
Allan

[Peter Ward]

Surprisingly not great...typically 2.5 on a good night. The system is however well baffled with very smooth optics...I'm guessing lower scatter gives higher contrast.