Image 1: Blue Snowball Nebula, NGC7662, Lac Teeples, 2023-11-12.
One more Planetary Nebula from the observing session of November 12 to 13 2023. This was a productive night in spite of the tricky-to-use SCT14 telescope, the very heavy frost, intermittent cloud and the frozen/jammed focus motor.
With all the Planetary Nebulae observed there was an inadequate amount of data collected, or time spent on the objects. Partly this was because when they disappeared behind clouds or trees I simply jumped to another target. It was also because I wasn’t sure I’d get anything at all from such small targets and wasn’t prepared to observe something all night only to have nothing in the end. If the opportunity arises I may collect more data on one or more of these targets and try to improve the resulting images.
This particular target was observed a bit earlier in the evening and I managed to get almost an hour of reasonably good data. I’m sure I had the telescope pointed at it for more than two hours to get this much. The focus was manually done because the focus motor was jammed/frozen at this time.
This nebula has a triple shell structure, of which two are visible here. The inner bright area is approximately 12 by 18 arcseconds in apparent size while the outer structure is around 32 by 28 arcseconds. There is a much larger and fainter outer ring that I didn't capture at all. Presumably that would take better conditions and vastly more data collection.
This target is smaller than Jupiter (~50 arcsec diameter). This tiny size means that the surrounding stars show plenty of flaws, including irregular colour (mostly due to poor focussing I assume).
The 14" Schmidt-Cassegrain has a very long focal length, meaning it is looking at a very tiny part of the sky. The smallest distubance causes the image to shake violently. If one of the bluebirds in the neighborhood sneezes that subframe is ruined.
Wikipedia says that this star exploded fairly recently, just over 3000 years ago. It also says that it is at a distance of 5,700 light years. I take this to mean that it first appeared to us 3000 years ago, but in fact it exploded 8,700 years ago since that light had been travelling for 5700 years before it arrived at the Earth.
The Blue Snowball can be observed with a fairly small telescope (per Wikipedia) but to see any kind of structure you need a bigger scope. I suspect it looks like a blue, perhaps slightly furry, star with a small telescope. With the 14” Schmidt-Cassegrain we are seeing a fair amount of structure within the nebula.
Blue Snowball Nebula, NGC7662, Lac Teeples, 2023-11-12. 51.5 minutes of data in 30 second subframes. Celestron SCT-14, ASI6200. No filter.
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