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Tuesday, January 28, 2014

A grande finale of the Cepheus project, mosaic of ten panels with colors



I have planned this Cepheus project for a long time. Finally I have been able to finalize it. I have done some large mosaic images of nebula rich areas in our Milky way. The ultra fast camera optics, Canon EF 200mm f1.8, it's a perfect tool for the job. It has a large, flat and sharp, image field and full open at f1.8, it collects photons very fast. The final image covers an area of about 18x10 degrees. (Full Moon has an apparent size about 0,5 degrees. 720 full Moons are needed to cover this area in the sky.)

To have a color image, each of the panels have been shot three times. This narrowband image is shot with QHY9  (a cooled astronomical camera), Canon EF 200mm f1.8 camera optics full open,  Baader Planetarium Narrowband filter set for an emission of ionized elements, Hydrogen, Oxygen and Sulfur.  (H-alpha, O-III and S-III) The dimensions of the final mosaic image are 12000 x 6500 pixels.


Emission Nebulae in constellation Cepheus 
Mosaic image of ten individual panels, total exposures 92h.
Click for a very large image, 3000 pixels wide and 7MB.

Mapped colors from the emission of ionized elements, R=Sulfur, G=Hydrogen and B=Oxygen.
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About 1:1 detail from the image above
Click for a full size photo

Lots of stars out there.


Cepheus Nebulae in visual spectrum
Composed from the narrowband channels

Image is in Natural color palette from the emission of ionized elements, 
R=Hydrogen + Sulfur, G=Oxygen and B=Oxygen + Hydrogen.
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B&W image with an emission of Hydrogen alpha only

Image of light, emitted by an ionized Hydrogen.
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A labeled image and orientation

Some main objects are labeled here


An orientation in constellation Cepheus. The mosaic image covers an area of ~18x10 dgrees.

Technical details

I have used lots of an older material for this image. I have shot this area for years, with a different instruments, with different focal lengths and apertures. The total exposure time for the final mosaic image is calculated by adding the exposures for the actual mosaic to the exposures for sub-images used.  

List of the sub-images used for a large, 10 panels, mosaic of Cepheus


Panels, shot for a final mosaic


Processing work flow

Image acquisition, MaxiDL v5.07.
Stacked and calibrated in CCDStack2.
Deconvolution with a CCDStack2 Positive Constraint, 33 iterations, added at 50% weight
An extra background normalization in CCDStack for a mosaic match.
Color combine for each panel in PS CS3
Panel composition in PS CS3
Levels, curves and the final color matching in PS CS3.

Imaging optics used for the mosaic image

Meade LX200 GPS 12" reduced to f5
Tokina AT-X 300mm f2.8
Canon EF 200mm f1.8

Cameras and filters

Imaging camera QHY 9, with a QHY filter wheel
Guider camera, Lodetsar
Active optics unit SXV-AO with Meade LX200 12" telescope
Baader Filter set, 7nm H-aplha, 8nm S-II and 8.5nm O-III

Total exposures used for a mosaic image

H-alpha 160 x 1200s Bin 1x1
O-III 66 x 1200s Bin 1x1
S-II 50 x 1200s Bin 1x1

Total exposures 276 x 1200s = 92h


Saturday, January 25, 2014

A zoom in series of the Cave Nebula, Sh2-155



Now and then I have published some zoom in series of various objects imaged by me.
The purpose is to show the apparent scale in the sky. Beside that, this series shows nicely the fractal nature of our universe.  Series are possible to make, since I have shot many objects with various focal lengths.
Like this one is shot with 200mm, 300mm and ~2000mm  focal lengths

The Cave Nebula, a study about the scale in the sky
Note. A circle, size of the Moon, in the images as a scale. (An apparent scale of the Moon is 0,5 degrees, or 30  arc minutes.)

All images are in Mapped colors from the emission of ionized elements,
R=Sulfur, G=Hydrogen and B=Oxygen.


Orientation in constellation Cepheus

An orientation in constellation Cepheus. The mosaic image covers an area of ~18x10 dgrees.









Friday, January 24, 2014

A new header image, Oxygen emission of the Eastern Veil nebula



I have added a new header photo. It shows a small portion of the Veil Nebula supernova remnant in Cygnus. Image shows the Eastern veil but only in light emitted by ionized Oxygen, O-III.

I have published this image at January 7 this year. A blog post about it can be seen HERE.


An emission of ionized Oxygen in Eastern Veil Nebula.


The Veil nebula SNR

This is an image about the whole Veil Nebula. A blog post about this image can be seen HERE
A detail image above can be seen at left edge of the image bellow. Click for a large image.






Thursday, January 23, 2014

A supernova remnant in Cygnus (Not a Veil nebula) reprocessed



I found six hours of unused H-a data, for this SNR, from my hard drive! Now the dim background emission of an ionized hydrogen is in balance with O-III emission of supernova remnant. The overall look and feel of the image is much natural, I think.

This is a rarely imaged target. I haven't been able to find an other color image of it, showing the whole supernova remnant. This is also one of the most difficult targets, I have ever shot. Due to a very dense star field, large angular dimension and a very diffused structure this is even more difficult target, than a Simeis 147 supernova remnant in Taurus. Total exposure time of 38h was needed to have this image.

G65.3+5.7 SNR has about the same angular dimensions, than brighter and more famous remnant in Cygnus, the Veil Nebula The angular dimensions are about 3x4 degrees.
NOTE, this image is updated at 20.01.2014. There is now a better H-a channel and the background is practically full of ionized Hydrogen, H-alpha.

G65.3+5.7 SNR, reprocessed with extra H-a data
A supernova remnant in constellation Cygnus

A bicolor image of the supernova remnant. An ionized Hydrogen emission (H-alpha) can be seen as Red and an ionized Oxygen emission (O-III) as Blue. Buy a photographic print from HERE

A detail image of G65.3+5.7 SNR
So many stars...

A closeup from the full resolution image, click to see it at maximum size.


Orientation




Technical details

Processing work flow:
Image acquisition, MaxiDL v5.07.
Stacked and calibrated in CCDStack2.
Deconvolution with a CCDStack2 Positive Constraint, 33 iterations, added at 33% weight
Levels, curves and color combine in PS CS3.

Optics, Canon EF 200mm camera lens at f1.8
Camera, QHY9
Guiding, Meade LX200 GPS 12" and a Lodestar guider
Image Scale, ~5 arcseconds/pixel
H-alpha, 69x1200s = 23h
O-III, 45x1200s = 15h
Total exposure time 32h

A single calibrated and stretched 20min O-III frame
O-III is the stronger channel!

Heavily stretched 1200s frame of the strongest channel, ionized Oxygen (O-III), doesn't show much.