nGC 2736, the Pencil Nebula

[Geoff45]

I've had a bad run with the weather, so I've taken to trolling through my archives to see if there were things that could benefit from a repro. I dragged out this one from January 2013. I wasn't really happy with the first attempt that I did at the time, so I never posted it anywhere. This one is better.
Telescope: William Optics ZS110 Refractor
Exposure: 200minutes spread over equal numbers (more or less) of R, G, B, L
Camera: QSI540wsg
Software: MaximDl (for acquisition), PixInsight
http://www.astrobin.com/135221/

[Bassnut]

Excellent Geoff, pretty deep. I had a go in NB, not good, although its a neb, it does look better in LRGB.

[Geoff45]

Thanks Fred. It does emit pretty strongly in OIII, so maybe throwing some OIII into the green channel would be a good idea. I'll be having another go at this with my 12.5" and new Proline 16803 when it's in a good position.

[Bassnut]

Whoa, a Proline 16803!. Quite an upgrade :eyepop:. Interesting to see what you do with that. 3nm NB filters too perchance?. Exy :P.

[Geoff45]

Not yet. Proline +7 position filter wheel+MOAG+7 filters (L, R, G, B, 12nm OIII, Ha, SIII)+connectors to PlaneWave didn't leave me with a lot of spare change. Maybe in the long term. Even the 12nm filters new are $500 each, although I managed to score these second hand at half price from Mike Sidonio.

[Rex]

Nice Geoff! Looking forward to seeing the result with your new camera.

[Geoff45]

Just checked the price. Exy is certainly the word! 3nm 50mm square Astrodon filters are $US1250 each. May be some time before I get a set of these.

Thanks Rex

[RickS]

Nice job, Geoff. LRGB works quite well for this one which I wouldn't have expected.

[Geoff45]

Thanks Rick. How would you have tackled it?

[Placidus]

Hi, Geoff, Lots and lots to see in this wider shot. Bok globules and dust lanes off to the right, and a meshwork of really faint stuff to the left of the pencil. I can see from your shot that I mis-framed my most recent effort. Great work. Best, Mike

[RickS]

Haven't really thought about it, Geoff, but most (all?) of the images I have seen have been narrowband. The received wisdom isn't always right, of course, as you've demonstrated.

Cheers,
Rick.

[strongmanmike]

That's a little more interesting than I usually see that field presented, lots more going on and to see than usual, different colors, so well done on that score :thumbsup: It suffers a bit in the warts department when viewed large though..but meah, still a very interesting image, enjoyed the view.

Mike

[cometcatcher]

That's a beautiful image. Lovely colours. Very well exposed. :thumbsup:

[FranckiM06]

It is really great shot :thumbsup:
Franck

[Geoff45]

Thanks Mike


Thanks Mike. Yep, the warts are there. In fact I was a bit hesitant to post this one because of the said warts. I think I can clean them up though if I go through a more careful repro.




Thanks Kevin and Franck

[multiweb]

Excellent shot Geoff. Love the colours on that one. :thumbsup::thumbsup::thumbsup:

[Geoff45]

Thanks Marc. It's surprising what you can do with an image that you'd written off.
Geoff

[alpal]

Hi Geoff,
I really like your pic.
I believe I could make it even better with a few minor touch ups -
mainly a star mask to reduce star sizes & a slight colour boost & more contrast.
I'll post another version if you want?

cheers
Allan

[Ross G]

Great looking photo Geoff.

Very nice colours.

Ross.

[Geoff45]

Thanks Allan. Go ahead and post. Nice to see what someone else makes of it. I actually didn't go all out with this one because my first processing attempt two years ago was a real bummer, so when I did a quick repro and got a much better result I stopped there. Now that I've got so many positive comments I'll have a more careful go at it.

[alpal]

Hi Geoff,
OK - a slight re-process:
https://www.astrobin.com/full/135667/0/

Is that a touch better?

cheers
Allan

[Geoff45]

Thanks Allan. Yes, the colours are much deeper without being overblown. I like the darker background too. Another repro is in order here.
Geoff

[alpal]

Thanks Geoff,
The hardest part was the star mask:
Only Deep Sky Stacker could do it well enough & I had
to divide the picture by 3 then make the mask on maximum star size settings
& then multiply the mask by 3 to use it later.
Even then the 2 biggest stars had to be masked manually.
Controlling those stars will be easier for you with the original data.
The rest was easy.

cheers
Allan

[gregbradley]

Nice image Geoff. Your original looks best as the repro has badly blown out stars with blue halos.

Yeah it would be nice to get those stars more under control - perhaps shorter subexposure times may've helped at acquisition stage.

The pencil neb though I thought was blue/red rather than teal/red.

Greg.

[Geoff45]

Thanks Greg. Allan's repro was from a jpeg, so problems were inevtable.

I think I can knock them down a bit when I do the repro

I'm not sure one way or the other. Have to check it out. I like the teal though.

[RickS]

There's a lot of OIII in narrowband images of the area so I think teal is probably accurate.

[alpal]

Hi Greg,
" badly blown out stars with blue halos. "

The stars are a lot softer in my repro.
The halos could be easily reduced by blurring but I thought they looked more natural as is.
There are many targets - one example is Thors Helmet where bright stars
can overpower a faint nebula.
In Photoshop you have to use fill & content aware to reduce them
as I did - then blend with opacity -
& it's very difficult - even if you have shorter exposures to work with & to then blend them back in.
These faint nebulas are tricky to process.


cheers
Allan