Four Panel Mosaic Vela SNR in NII and OIII

[avandonk]

Image here 6MB

http://d1355990.i49.quadrahosting.com.au/2014_06/VSNR_NOO_4P_N_3k_.jpg

FoV is 6x6 degrees

Bert

[bkm2304]

Congratulations, Bert. Truly wonderful example of what is obviously a lot of patient work. What are the specs?

Richard

[strongmanmike]

Wow :eyepop: now that's the sort of thig you were always hoping to be able to do with that little scope, huh? Well done :thumbsup:

Mike

[niharika]

Wooooh! Massive FOV and amazing view!!!!! One of your best in recent time IMO.

[gregbradley]

That's a great image Bert. Your finest. Love Vela SNR mosaics.

Greg.

[cazza132]

Wow! - Very nice! What equipment did you use?

[batema]

That is absolutely stunning. Great job.

[Bassnut]

Gaud thats insane. So very well done Bert :thumbsup::bowdown:

[el_draco]

Extraordinary detail.... That bright little cirrus like extension on the lower right is beautiful. Wow!

[Stevec35]

Very impressive indeed!

Steve

[astronobob]

Extraordinary Bert :eyepop:

[Joshua Bunn]

That's insanely awesome Bert, what a wonderful job you have done.

[Shiraz]

wow, that is outstanding Bert - really well done

[AG Hybrid]

Why isn't this APOD?

[avandonk]

Thanks for all the nice comments. I have been busy going slowly more mad/insane than ever, trying to master PixInsight. The only way to learn is by trial and error. Be prepared for more errors than you can imagine. The results in the end when you finally win, are worth all the pain.

The image in the original post was stitched together with RegiStar. All previous processing done with PI. Even 3nm NB filters suffer from nasty gradients at the 3.5x3.5 degree field of the RH200. This means it is almost impossible to make seamless mosaics.

I have worked out a protocol with DBE to almost totally eliminate gradients.

This image was made with Gradient Merge Mosaic in PixInsight 14MB

http://d1355990.i49.quadrahosting.com.au/2014_06/VSNR_4P_NOO_PI.jpg

The lack of seams is obvious.


If you think the above image is stunning I am now working on a Hubble Palette version of the same data plus SII of course that is even better.


Here is panel one at full stacked resolution ie x1.5 sensor size. 15MB

http://d1355990.i49.quadrahosting.com.au/2014_06/VSNR_P1_HP.jpg



Hubble Palette is of course SII to red. NII or HA to green and OIII to blue. It is then adjusted using this method

http://bf-astro.com/hubblep.htm

The very dim detail in red and blue is vastly enhanced because human vision is far more sensitive (x20) in the green part of the visible spectrum compared to red or blue.

The simplest way to think of it is that the 'red' data modulates green to give a yellow signal and the blue data modulates green to give a cyan signal.


Bert


Exposure details. Each filter had about 20x16min or 5 hours exposure for each panel. So 4 panels X three filters x five hours = 60 hours of data at F3. To collect equivalent data at the same resultant signal to noise at F5 would take more than 160 hours.

[Regulus]

l usually go to Hubble sites for images like this Bert, They are beautiful-
l really look forward to the next installment with the Hubble palette.
l second the question - Why isn't it APOD?

[avandonk]

I have not submitted it yet?

Bert

[Paul Haese]

Nice detail Bert. Colour in the first one is very good. Maybe some more work on the panel joints at the bottom, but a very large project by the looks. I would maybe think increase your overlap for the mosaic and then crop out a segment to allow a seamless mosaic.

Not much noise either. Certainly your best to date.

[strongmanmike]

You love that area of sky huh Bert? ;) how many times have you imaged it now? :lol: This latest Hubble version panel certainly looks rather good :thumbsup:

Mike
who wishes he had an OS RH200 :sadeyes:

[multiweb]

Superb vista. Little noisy but great details. Would look awesome with more data to smooth it all out.

[cosmophoton]

Outstanding work, and amazing level of detail.

[gvanhau]

Very Nice one.

How many hours have you spent on it until now?


Geert

[avandonk]

Two panel HP starless 12MB

http://d1355990.i49.quadrahosting.com.au/2014_06/VSNR_2P_HP_SL.jpg


Bert

[avandonk]

Mike ever since I made a 11x11 degree RGB+NB mosaic of this region with the 5DH many years ago I have wanted to do a better version. The problem is that even the bright bits are very dim.

So far weather has been the main limiting factor. I will collect more data soon when Vela is up in my Eastern sky again.

I have found the more you do something and look at the result critically and then do it again, it only can get better.

Here are the first two panels with stars. 15 MB

http://d1355990.i49.quadrahosting.com.au/2014_06/VSNR_2P_HP.jpg


Bert

[avandonk]

A few thoughts


After stacking PI produces a 32 bit FP image. It can produce a 64 bit one.

All further processing was done in 32 bit linear form ie unstretched.

Why is this important?

All the dim nebulousity is in about the bottom 2% of the 16 bit image. This at best is about 1300 levels (0.02x65000) which is 10 or 11 bits.

By stacking many images into a 32 bit floating point image this bottom 2% now has many more levels available. Millions in fact.


When we now apply DBE Dynamic Background Extraction and ATW Atrous Wavelet Transform to this 32b FP data the result is far more mathematically valid.


Without DBE and ATW this very dim data would not even appear, let alone almost noise free.

ATW is the best method I have seen to reduce noise in the dark background without affecting ANY signal.

More on this later.

Bert

[cometcatcher]

That's incredible.

[John Hothersall]

That is just mesmerising, structure is sod detailed.

John.