Is this the firs narrow band color image, showing the whole Sh2-221, in the World?
This was one of the most difficult targets I have done so far. Supernova remnant Sh2-221, SNR G160.4+02.8, HB9, locates in constellation Auriga and has an angular dimensions about 2.5 x over 3 degrees. I never seen or red about the extended ionized Oxygen area, visible in my image as blue.
About 33h of exposures with extremely fast camera optics, Canon EF 200mm [email protected]
, was needed for this image. Total exposure time for the mosaic image with Sh2-216 is about 58h.
This could be the first narrow band color image in the world out of this target. Generally, there are very few images out of it. I couldn't find an other image showing the whole remnant. I have shot this area before but at the time part of the Sh2-221 was missing. This new image of mine is much more accurate and deep.