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Monday, September 23, 2013

Sharpless objects, 223, 224 and 225 in Auriga, reprocessed

I'm waiting the weather to clear, to be able to open up my Autumn season. While waiting, I have practiced my processing skills, after a long Summer pause. 

Sh2-223, 224 and 225
In constellation Auriga, click for a large image.

Image is in mapped colors, from the emission of ionized elements, R=Sulfur, G=Hydrogen and B=Oxygen.

Image in visual spectrum

A closeup of the supernova remnant Sh2-224



About the new processing

I have used a new technique to dig out a very dim background nebulae. A starless version of 16h H-a exposure is stretched to an extreme and a data in level of background bias is revealed. 
To work, images, used with this technique, has to be perfectly calibrated with bisas corrected flats.

The power of this method can be seen easily, if the new image is compared to an older version HERE.

A data hiding near the background level is revealed in this starless image. 
This "tone map" is used to boost an extreme dim background nebulae in the final image.

Technical details

Camera, QHY9 
Optics, Canon EF 200mm f1.8 @ 1.8 
Guiding, QHY5 and PHD-guiding 
Imaging platform, LX200 GPS 12" 

H-alpha, 7x1200s, 13x2400s and an additional 
15x1200s  imaged with QHY8 and Tokina AT 300mm f2.8 
O-III, 5x300s Binned 4x4 
S-II. 5x300s. Binned 4x4 . 

A single 1200s H-alpha frame
Calibrated, stretched and scaled down, no other processing

This single 20 min. exposure shows how dim this target really is.
There are very few images about this area of sky around.

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