Carina Nebula in 3nm NII HDR

[avandonk]

I am sorry for yet another Carina Neb but it is a good test object. The Moon was full so I had to find something to image well away from it.

Exposures in 3nm NII, 15x1 min, 10x4 min and 7x16 min. Used these three exposure stacks to tone map a HDR.

Full res image 6 MB FoV 3.5 x 3.5 degrees.

http://d1355990.i49.quadrahosting.com.au/2012_11/CAR_NII_HDR.jpg

The extra detail visible made it a worthwhile exercise.

Bert


Astrograph is an Officina Stellare RH200 which has a focal length of 600mm and is F3, yes F3! Clear aperture is 200mm.
FLI Atlas Focuser.
FLI ten position filter wheel CFW-3-10 with 50mm square filters.
Astrodon E series LRGB and HA, NII, SII and OIII 3nm NB filters. Also a continuum filter 5nm.
Camera is a FLI PL16803 which has a sensor size 36.8 X 36.8 mm.
The FoV of this system is 3.5 X 3.5 degrees.
Mount is a Software Bisque PMX.

[Larryp]

Heaps of detail in that, Bert-good one!

[PeterM]

Wow, so much happening in there. What a great image.

[cometcatcher]

If you didn't mention it was Eta Carina I probably wouldn't have figured it out. It looks so different, and fascinating.

[Ross G]

Such an amazing view of a well known object...unique.


Ross.

[jjjnettie]

Spectacular!!

[Poita]

Wow, stunning view. I'm jealous of your filter setup!

BTW, what is causing the eggy stars top left and top right in that image? The bottom left and right both look nice and round.

[David Fitz-Henr]

Yes, excellent details in this image! The eggy stars look like a collimation issue - with such a fast f/ratio and such a large chip you will need to take particular care to get the collimation right.

[avandonk]

If I spent all my time worrying about eggy stars at the corners on a sensor far bigger than the corrected field of the RH200 I would never get, and you would never see any images.

Conversely I could put up small jpg artefact compromised images where all the stars were mere blocky thingies that did not look like stars at all but at a distance still looked like stars. Just have a look what is on the internet and see at what sort of definition the so called 'perfect' images are published and the plethora of acolytes that do not have a clue.

Please do not rave about blocky images and then have the nerve to to say a part of an image at far higher resolution is not quite correct.

Please do not tell me something I already know full well. If you have followed what I am doing you you find how difficult F3 and very large sensors are to manage as far as focus and flexure are concerned. The tiniest variation can lead to eggy stars. We are talking about tens of microns here.

Does your optics stay within focus over about 15C degrees of ambient temperature variation within 20 micron? Thought not.

All that aside the depth of faint nebular detail is very good. At least nebular detail never looks eggy!

Of course the brighter stars will show any minor flaws when the exposure is such that faint nebulosity has a decent signal to noise.

If you want perfect stars just image at F10 and see very little nebulosity and a tiny field of view.

The choice is yours.

To all those that saw the image in its entirety to show the dim stuff of the Carina Nebula I thank you.

Bert

[Regulus]

I think Peter was just curious about how those particular eggs got there and David was suggesting a possibility. I didn't read it as an assault on your photography technique or processing, equipment or artistic choices.
Or as a slight on you. These kinds of questions are regularly asked in the photo forums, it's how we learn.

Eta Carine is one of my top five favourite objects and that is a truly stunningly good photo. Thanks for sharing it.

Loved the Horse Head pic BTW and really liked the colouring of it.

Trevor

[avandonk]

You are quite correct. I just thought that a clarification was needed. It was no more a criticism than the original comment.

Bert

[Bassnut]

Well that's very excellent and even more very interesting. Wonder how you would fit NII into a NB oiii, SII, ha blend?.

[avandonk]

Give me time and clear weather and it will be done.

NII is better than HA as it has better definition. Just replace HA with NII.

Half or more of what comes through a 5nm 'HA' filter is NII for most targets.

bert

[Poita]

Thanks for the reply Bert, I was interested from a technical standpoint why they were there.
I hadn't followed your entire journey with the scope, I've gone back now and had a read.

I image at around f2, at a staggeringly lower budget of course, and have similar issues, so was interested to find out if the cause was the same.
I agree, it is worth having the full images to appreciate rather than cropping them down.The extended view of the nebulosity is worth it.

[strongmanmike]

Huge amount of nebulosity there Bert :thumbsup:

As a comparison, I have attached a 100% res image I recently did of the Hens Cluster...what do you think? do my stars look too eggy in this? :question:

:P

[multiweb]

Top shot Bert. Nii looks the way to go. The contrast in the low light areas is obvious.



Hmm.... on axis comatose. Nicht gut... :P

[dvj]

You are lacking magenta in that image Mike. Disturbing.

[avandonk]

Here you go Mike all fixed. They look far rounder now.


Bert

[strongmanmike]

Ma ma ma maaaa magenta (sung by The Knack)



:lol:...ah eggsactly! much better :thumbsup:

And here's a Gleason version so he doesn't feel left out :P

Mike

[Regulus]

Excellent processing job on Stronmanmikes eggys guys. I have learned much.

[avandonk]

Cloud cleared about 1AM this morning and I collected another frame.

Here is the two panels 5MB

http://d1355990.i49.quadrahosting.com.au/2012_11/CAR_2P.jpg

This weather site is very good at predicting your local weather

http://www.accuweather.com/en/au/yallambie/15844/hourly-weather-forecast/15844?hour=0

You need to put in your nearest BOM station.

Bert

[Regulus]

That is excellent and I think may be the best picture I have seen of this object. It will inform my next sighting of the Nebula and i look forward to that. Thx - Trevor