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Mysterious bluish structures in Cassiopeia Part 3: Oiii with Hyperstar

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Last night I got my first proper light with my EdgeHD11 with Hyperstar v4, which compared to my RASA8s can fit in a filter drawer so I can easily change filters (and of course it has twice the light grasp of a RASA8). I put in a Baader 4 nm Oiii f/2 filter and aimed at the mysterious blue object I discovered in Cassiopeia about a month ago (https://www.astrobin.com/cnvp2s/). I then imaged it with RASA8 and an IDAS NBZ dual-band filter (Ha+Oiii) so it was likely a Oiii emitting object, but that filter also let some blue reflection nebulosity through (especially with a light bucket as a RASA). So with the Hyperstar I wanted to make sure it was Oiii the object was emitting. Unforunately I only got 6 x 5 min before clouds moved in. However, for this 11" f/1.9 scope that was enough to reveal a clear Oiii signal, although a bit noisy.

When I posted my RASA image Marcel Drechsler enlightened me that the object was registered in Simbad as  GSH 122+02-77 "Interstellar Shell" (http://simbad.cds.unistra.fr/simbad/sim-basic?Ident=GSH+122%2B02-77&submit=SIMBAD+search) with no further info and it has apparently never been imaged. At least we can now be quite sure it is emitting a significant amount of Oiii. Marcel has just sent this and my previous image to Prof. Robert Fesen at Dartmouth College in the US for evaluation - could possibly be a new SNR, I keep my fingers crossed.

Surprisingly, the Hyperstar v4 with a APS-C camera was producing good enough corner stars right out of the box (although I bought it second hand) and the small deformations was easily taken care of by BlurXT2. A tri-Bahtinov mask I put on last night gave a quite symmetric spike pattern, suggesting no collimation is needed (I have the Hyperstar in a fully screwed in position). That was a big releif. Camera used was a QHY268MM, all on an EQ8 in an obsy next to my dual-RASA8 rig (I will definitively not stop using that).

Cheers, Göran

Here is the Hyperstar Oiii image from last night:



And the RASA IDAS NBZ image from February:



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3 hours ago, ollypenrice said:

Great stuff, Goran.


Thanks Olly! Would be nice if it is a unrecognized SNR😃

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