This is the processed result of 10 hours worth of 20 minute RGB sub-frames.
Back in January I took a couple of 1 hour exposures of Sh2-216 using my Ha filter. Nearly one year later, a spell of good weather over a weekend meant that I was able to add a few more and I now have 10 hours worth.
Sh2-216 has been calculated at a distance of 129 parsec (420 light years) by measuring the parallax of the central star which places it much closer than the Helix and Dumbbell nebulae at 219 & 379 parsec respectively.
It measures about 2 arc degrees on the sky and is very faint.
It’s been a while since I last visited this object, a dust cloud on the Andromeda / Cassiopeia border (http://littlebeck.org.uk/?p=1058 & http://littlebeck.org.uk/?p=948). This is the first time with a monochrome camera and RGB filters; previous attempts have been with the KAF8300 equipped QHY9C OSC camera.
The field with the G3-16200 is much larger and provides a better context for the object. Better data, and much improved processing skills have revealed a lot more of the surrounding faint clouds.
This is about 12 hours of RGB data acquired in 10 minute subframes. I’m not a fan of LRGB imaging and very rarely use luminance, preferring instead to spend longer capturing the colour data at bin 1×1. Processing is exclusively Pixinsight.
Displaying the monochrome Ha image in a local exhibition of pictures was a spur to getting to grips with the colour data I’ve acquired for this image. With the Ha & RGB data this now amounts to 51 hours in 10 & 20 minute sub-frames.
The image is reduced to 40% of full size for display here (click on the thumbnail).
This object is the remnant of a supernova explosion that occurred some 40,000 years ago and the shell has been expanding ever since. It now spans about 3 degrees on the sky, which at it’s estimated distance of 3000 light years is 157 light years in diameter.
This image was published in the June 2017 edition of Astronomy Now.
It’s been a while since I last posted here. Images are posted first to the Breckland Astronomical Society Facebook page which a more interactive medium for discussion.
I’ve been busy in the meantime gathering images of the supernova remnant Simeis 147. This is a huge object requiring a 4 pane mosaic to cover it. So far I’ve only completed the Ha image to my satisfaction.
In 1966 when George Abell compiled his catalog of planetary nebulae entry 85 in Cassiopeia was mis-classified. While it has some resemblance to a planetary nebula it is subsequently been found to be the remnants of a supernova explosion . However, unlike the Cygnus loop it’s emission is mainly in H-a with very little O-III.
I’m still collecting data for this object but this is a process of the first 12 hours of images shot through a Baader 3.5nm Ha filter.
There is an older, fainter supernova remnant in Cygnus and it lies just up from the double star Albireo. At about 30000 years old (Veil 7500 years) and further away 2500 ly (Veil 1500 ly) it is correspondingly fainter. The part I’ve imaged here has the designation Sh2-91.
I last took pictures of this object back in 2014 with my QHY9 colour camera and it wasn’t entirely prominent but by combining the old data with 4 hours shot through my new Baader 3.5nm Ha filter a more distinctive image is formed.
I’ve rejected some of the original frames that had some thin cloud and re-stacked, then registered the new Ha frames and combined using the Pixinsight NBRGBCombination script.
I finally took the plunge and ordered a Moravian G3-16200 camera. This is a monochrome camera and whilst the pixels are slightly larger than the KAF-8300 equipped QHY9 there are also a lot more of them. Setting up has been rather a long process that still isn’t completed but at least it’s attached and able to take pictures. The increased sensor size and weight has highlighted some issues with my Takahashi FSQ85-ED Baby-Q. There is some tilt in the optical train and stars are elongated in the corners. Hopefully, I’ll be able to work out solutions for these problems.
One of my purchases was a Baader 3.5nm Ha filter and this image was taken with it last night. The night’s are still very short here so only 2 hours in 20 minute sub-frames of the emission nebula IC1396 in Cepheus.