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Tuesday, November 22, 2011

Cygnus project, the grande finale

Mosaic of dancing Nebulae
in constellation Cygnus

An Eight panel mosaic of Nebulae in Cygnus in mapped colors.
NOTE, this is a largish file, 1400x1950 pixels and 2,8 meg.

Direct link to a 2000x3000 pixel version HERE. (7,5 meg)
(Original one is ~14.000x10.000 pixels)

It took couple of Months to shoot all the needed frames for this mosaic and I did use every possible clear moment. This mosaic image has eight full size (3500x2500 pixels) panels and the final image has a massive size of 7.000 x 10.000 pixels. For every panel, I shot three different images of emission of ionized elements, Hydrogen, Sulfur and Oxygen. (H-a, S-II and O-III). This image is a mapped color composition showing Hydrogen as Green, Sulfur as Red and Oxygen as Blue. 

Image spans about 10 degrees horizontally and 14 degrees vertically. (Apparent size of the full Moon is ~30 arc minutes = 0,5 degrees. Full moon fits to this are at about 480 times!)

Generally this mosaic took a lots of work to finalize and it was kind of difficult to process since the star field is so very dense at galactic plane. Overall I'm happy with this result!

Northern constellation Cygnus (aka "Norther Cross") locates at the plane of our Milky Way and it's a treasure box of beautiful nebulae. Bright supergigant star Gamma Cygni can be seen at center Right, next to the Butterfly Nebula, IC 1318. The bright Blueish spot at upper Right is the Crescent NebulaNGC 6888.
At top Left, a beautiful open cluster, NGC 6819 , can be faintly seen. (It's well resolved in full res. image)
Two bright objects at bottom middle are Sh2-112 and a bluish Sh2-115. At bottom Right are parts of the North America and Pelicän nebulae visible. The propeller Nebula can be seen at center left. There are many other objects in this large field.

Overlay with a star map.

Closeups from the large panorama

Click for a large image! 

Open cluster, NGC 6819, at middle, from upper Left corner of the mosaic. 
I have finally teamed this f1.8 lens and now all of the stars are pinpoints to edge to edge!

Closeup from lower Right corner shows part of the North America & Pelican Nebulae.

The Crescent Nebula from upper Right.

Gamma Cygni from center Right and a part of the Butterfly Nebula.

A closeup of the "Cirrus" area from lower Left of the large mosaic.

New pictures from the panorama material

Since I now have a load of processed panels for the panorama, I have composed some new individual high resolution images out of them.

Click for a large image!

Mountains and dust of Pelican Nebula

A two panel panorama from Butterfly to the Crescent nebula

A two panel mosaic from the "Cirrus" area to the Butterfly Nebula

I started this project by shooting a Three panel mosaic of "Cirrus of Cygnus"

"Cirrus of Cygnus", this area can be seen at Left in an image at top.

A "Natural" Color composition from the emission line channels

As usually, I have done color compositions close to visual spectrum from narrowband channels. Since I have so many (too many...?) images in my blog post, I show just couple of them here. The method used for this color scheme is following:
R=80%Hydrogen+20%Sulfur, G=100%Oxygen and B=85%Oxygen+15%Hydrogen to compensate otherwise missing H-beta emission. This composition is very close to a visual spectrum.

Click for a large image!

Large Eight panel mosaic in natural color composition from the NB channels

A two panel mosaic from the same material.

An animation, nebula with and without stars

This animation will show more details in the nebula, since human brains gets easily fooled to see shapes in a cloud of dots, like stars are. Please, let the animated GIF load for few seconds to see it animated. ( 1,2 meg)
Click for a large image!

I think, that dim Blueish arch like formations, seen at top Left, are some reflections.
8,5nm O-III filter is too wide. to block all of the light pollution. and reflections can happened. 

Technical details

I have used a very fast camera optics, Canon EF 200mm f1.8, full open to collect all the data in this mosaic. Due that, total exposure time is relatively short, ~15h, there are some very dim formations clearly visible.

Processing work flow:
Image acquisition, MaxiDL v5.07.
Stacked and calibrated in CCDStack2.
Levels, curves and color combine in PS CS3.

Optics, Canon EF 200mm camera lens at f1.8
Camera, QHY9
Image Scale, ~5 arcseconds/pixel
Guiding, Meade LX200 GPS 12" and a Lodestar guider
Filter, Baader 7nm H-alpha and Baader O-III 8,5nm

Exposures for Eight panels,

Panel 1 (Top Left), 
H-a, 3x900s Binned 1x1
O-III, 2x300s Binned 3x3
S-II, 2x300s Binned 3x3

Panel 2 (Top Right), 
H-a, 5x900s Binned 1x1
O-III, 6x300s Binned 3x3
S-II, 6x300s Binned 3x3

Panel 3 (Upper Left), 
H-a, 3x900s Binned 1x1
O-III, 3x300s Binned 3x3
S-II, 2x300s Binned 3x3

Panel 4 (Upper Right), 
H-a, 4x900s Binned 1x1
O-III, 6x300s Binned 3x3
S-II, 6x300 Binned 3x3

Panel 5 (Lower Left), 
H-a, 5x900s Binned 1x1
O-III, 3x300s Binned 3x3
S-II, 2x300s Binned 3x3

Panel 6 (Lower Right), 
H-a, 8x900s Binned 1x1
O-III, 6x300s Binned 3x3
S-II, 6x300 Binned 3x3

Panel 7 (Bottom Left), 
H-a, 6x900s Binned 1x1
O-III, 3x300s Binned 3x3
S-II, 2x300 Binned 3x3

Panel 8 (Bottom Right), 
H-a, 4x900s Binned 1x1
O-III, 2x300s Binned 3x3
S-II, 2x300s Binned 3x3

Total exposure time for all channels ~15h

Top of light exposures, there are calibration files shot.
H-a, 21 Flat frames
O-III, 21 Flat frames
S-III, 21 Flat frames
All filters:
99 Bias frames
19 Dark frames

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