Astro Anarchy

Sunday, October 30, 2011

Veil Nebula, a supernova remnant

Veil Nebula

Supernova remnant in constellation Cygnus

Note. Image is updated at 27.03.2012 with a new data, it was buried in my hard disk.

Image is in Natural color palette from the emission of ionized elements,

R=Hydrogen + Sulfur, G=Oxygen and B=Oxygen + Hydrogen.

Last night I collected few more hours H-alpha emission, between the clouds, for this SNR in Cygnus.
Image is not as deep as I wanted but the weather has been working against me for a long time now...

Veil Nebula is a cloud of ionized gas and dust, leftovers from an exploded star. The star exploded some 5000-8000 years ago at distance of about 1470 light years. This, relatively faint target, is difficult to image due the large angular diameter, about three degrees, and a dense star field.
This is a second version of this object, older version can be seen Here. I have made a 3D-animation about the possible shape of this SNR, it can be seen Here.

HST-palette, from the emission of ionized elements,

R=Sulfur, G=Hydrogen and B=Oxygen.

1:1 cropped image to show the resolution.
Not a bad one for the 200mm camera lens...

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 50% 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

New exposures H-alpha 13x1200s,

S-II and O-III information are from an older image

Monday, October 24, 2011

Image processing test with Sharpless 119

I made a test, how image resolution gets effected by a stacking algorithm. When images are registered, they are moved and rotated by a fraction of the pixel accuracy. Depending on used algorithm, there will be some level of blurring in a final stacked image. In this test, CCDStack software is used to calibrate, register and stack the raw-images. Two similar processing are made from the same material, one with normal workflow and the second with images scaled up 200%.

This is a 100% animated crop from images, stacked from a 100% size and 200% size calibrated frames.

10 x 1200s H-alpha with a QHY9 camera and the Tokina AT-X 300mm camera lens at f2.8.

"Mitchell" algorithm is used for up scaling all of the 200% sized frames.

An animation from a single, cropped and 400% up scaled, 1200s H-alpha exposure.
One image is registered and second not. HWFM in none registered image is 1,6 and in registered 2,4.
Method of register is most commonly used Bicubic B-spline.

Specially, if image are undersampled, like in this example, the blurring effects gets stronger and there is a risk to loose some of the finer details.
Down side of up scaling images to 200% large, is the needed amount of computer power and memory! Images will be four times large in file size. In this case a single frame, saved as a 16bit TIFF, will be about 130 MB.
CCDStack will use much more memory per image since images are internally processed as a 32bit floating point image space. All post processing in PhotoShop is done to a 200% sized version.

I have reprocessed Sh2-119 images with a new method, original versions can be found here: http://astroanarchy.blogspot.com/2011/10/sharpless-119-sh2-119.html

Sharpless 119

In constellation Cygnus, Ra 21h 18m Dec +44 00'