Greg from the NFO recently drew my attention to this interesing region in Cassiopeia. Lots of open clusters and nebulosity, and a supernova remnant as well. I tried to image it....

This great region has a host of open clusters from various catalogues. NGC 7790 and NGC 7788 sit in a chain with most obscure clusters such as King 12, King 21, Frolov 1, Harvard 21, Berk 58 and Czernik 1 and a few others besides. Over on the right of the frame is the relatively bright SH 165 region from the Sharpless Catalogue of hydrogen Alpha regions. Below this is the much dimmer sh166. Various other small Sharpless regions lie just outside the frame.

See my image of CTB1 with full details and full resolution image.

In the upper left we find the main target, CTB1, a very faint supernova remnant. This is extremely faint and very difficult to extract from the background stars.

Using a 6nm Hydrogen Alpha filter allows us to attenuate the stars, but the large amount of stretching needed to make a picture of the supernova mean that the star brightnesses are very hard to control. Filter manufacturers are now finally beginning to see sense and are producing high transmission 3nm FWHM narrowband filters, and one of these would do a far better job of extracting this nebula from the rich starfield of this part of the milky way.

I like this region because it shows the different stages of a star's life. We have big clouds of hydrogen waiting to become something, some hot active star forming regions leading onto some open clusters of established stars. The Supernova remnant itself is the final phase of a star's life before the bubble disperses into the interstellar medium reading to take part in the formation of more new stars and solar systems.

I've used data from two nights to construct this image. A total of about 10 hours of data has been used. This makes regions of faint nebulosity present well with low noise, but the lack of contrast makes the CTB1 region itself difficult to highlight.

To be honest I don't think I've ever captured quite so much data to produce such an uninspiring region. You can only appreciate the difficulty of this object once you've tried imaging it yourself. I've seen some fantastic images of this object taken with camera no so different from my own, so I'm slightly disappointed at how this has turned out. Clearly I need darker and more transparent skies!

It might be possible to produce a full tri-colour narrowband image of this region. I did collect a couple of hours of SII data on a previous night, in which you can clearly see the ring shape. However, I've got a serious backlog of OIII data capture to work on during the new moon period, so this might take a back seat - we will see!

See my image of CTB1 with full details and full resolution image.