Ngc 2997

[Peter Ward]

A work in progress....despite some clunky flats, gradients, a few petra-watts of urban sky-glow and satellite trails that persist with median/SD/you name it stacking...

I'm pretty happy with results to date.

The link is here (http://www.atscope.com.au/BRO/gallery371.html)

[multiweb]

That looks fantastic already. The resolution and sharpness are unbelievable. :thumbsup: Would be interesting to point your beast towards M83. It's in a good position now.

[RickS]

Looks very sharp, Peter. The colour is a bit iffy with a blue cast to the background and mostly orange stars (the image doesn't have a colour profile so this could just be a colour management issue.)

Cheers,
Rick.

[Peter Ward]

Ta. Profile added....but probably won't fully nail down the colour tint until I get to reprocess in PixInsight (I used MaxIm's gradient routines for this one)



Thanks Marc... Oddly enough I've detected some small collimation errors
are now obvious with occasionally good seeing, so I think the Alluna can d a little better still.

Humm Eta or M83 :question: :D

[gregbradley]

That is very impressive. Great detail in the core areas. Fabulous.

Greg.

[multiweb]

Well.... why not a bit of both.

[Atmos]

I noticed a blue cast in the background earlier but kinda assumed that it may have been caused by viewing on my iPhone :P

Very sharp Peter, the core and dusty regions look fantastic!

On the RHS of the image the stars don't look quite perfect, is this the collimation you're referring to? Or is that a small amount of field curvature?

[Peter Ward]

Thanks for the feedback.

I think there are a couple of things going on, but field curvature is not one of them. I suspect a smidge of camera tilt correction and further collimating is required (16803 chips are very unforgiving).

That said, I'm finding the systems ability to resolve filagree details to be quite remarkable :)

[Atmos]

I do remember you posting a curvature map of your system, being at about 5-8% or something. Couldn't remember if that was with a 16803 or a smaller sensor. I do remember a part of a conversation between Greg and yourself about possibly needing a corrector. Random fragments of conversations coming back into the frontal lobe :P

Regardless, it is a wonderful start!

[Regulus]

It's a beautiful image Peter, and a shame about the ovoid stars down the right, because the sharpness and subsequent detail is great.
I never noticed the kink in the 'upper arm' before, so i cannot have paid much attention to other pics of this galaxy.
Nicely done (hope to see another of it one day with the re-collimation done).

Trev

[alpal]

It's looking good Peter &
some more data will only improve it.
It's a bit of a difficult target unless you're at a dark site.
It does seem to have a purple/magenta colour as per here:

http://cseligman.com/text/atlas/ngc29a.htm#2997

cheers
Allan

[Peter Ward]

I'd say it's a difficult one.... even at a dark site. To get a handle on the colour and fine structure prior to processing, I can't say I saw any top-shelf examples taken from Oz on the web...I suspect they are there, just haven't found them yet. Happy to be pointed to some useful URL's though.



I should have bolted my STT8300 to the scope...then the entire field would have been perfect :doh:





The scope has the optional dedicated corrector attached...and a separate focal reducer corrector (yet to be tested). That said...given the lower right data is uncropped and at the extreme edge of a 16803....

...I'm really not too fussed.

[Placidus]

Hi, Peter,

The image looks very beautiful - the dust lanes in particular are joyous.

The link seems to point to an image that is only 1283 x 1268 pixels. Is that intended? It looks to me like it would show well with at least twice that. Perhaps I'm doing something wrong in following the link.

Very best,
Mike

[Peter Ward]

Thank you Mike. Yes, the linked image is not particularly large. Sadly I find plagiarism is rife on the net, so choose not to make overly HD images freely available.

[billdan]

Beautiful Galaxy Peter, the detail in the core is exquisite, shame about the sat trail. At least you will know its yours if someone else plagiarises it.

Regards
Bill

[Peter Ward]

Thanks.. As an aside, I recall David Malin giving a talk many years ago, where he mentioned the AAO used to add/remove a star or two from published images (in the pre digital era) which they would use to prove copyright.

Royal Observatory Greenwich also had submissions that clearly had Hubble data layered into them....it's amazing what a 3" refractor can do these days :lol:

[Stevec35]

That's an excellent NGC 2997 with great detail Peter. Great composition too.

Cheers

Steve

[marc4darkskies]

A tough target and looking good so far Peter, but really? 33% res? You're leaving too much to the imagination at that scale! I'd love to see what that rig can really do! What sort of FWHM did you get for the raw subs? Did you do any decon or was it too noisy?

[rustigsmed]

Excellent sharpness and resolution Peter - must be tough from the suburbs!

Russ

[Peter Ward]

Thank you gentlemen for your comments....I suspect many are unaware I'm dogged by urban skies...making imaging targets like this difficult, but not impossible.

I have to grab 4x more data to get a similar S/N ratio to dark-sky users....but then again, my observatory is just 10 steps away from a cold beer and BBQ in my yard.

Imaging can be civilized :D

Marcus...well, I need to keep 'em guessing :)

The seeing was pretty bad for most of the data, FWHM's of 3-4 arc sec most nights. I ran the raw data over CCDinspector...there is a definite tilt in the system :doh: which I suspect is blowing out the data a good arc second or more. I'll try and fix it tonight.

Decon? What's that? Bah! Humbug I say!

[marc4darkskies]

3-4 arcsec?! YUK!!! That certainly explains your scaling! I don't bother imaging Lum if seeing is beyond 2.5 and I'll throw away subs straying over 2.5 in any case. If I don't stick to this, even after decon I get a frame full of fuzz balls. Hopefully you'll get a couple of good nights soon!! I find the warmer nights have a better chance of good seeing around here (somewhat counter-intuitive but empirically true).

PS: Decon is your friend!! :)

[Flugel88]

Looks very sharp Peter considering seeing conditions.
Around the core and dusty regions look little dark but it sure does made the detail pop out.
Stars are looking lovely too.
I would be stoked with such an image :)