Image 1: M76 captured at Lac Teeples on November 12, 2023.
Image 2: M76 captured at Lac Teeples on November 12, 2023. Reprocessed to remove the stars, shrink them, and then add them back.
Messier 76, the “Little Dumbbell Nebula” (also known as M76, NGC 650/651, the Barbell Nebula, or the Cork Nebula) is a “planetary nebula”, a region of ionized gases emitting in a range of colours. The energy for this nebula comes from the explosion of two stars, creating a two-sided dumbbell of emission. It is somewhat similar to the “Dumbbell Nebula”, M27.
In apparent size it is quite small, just 2.7 by 1.8 arcmin. The moon is 30 arcmin across. Jupiter is around 0.75 arcmin across. At a distance of 2500 light years, this means that this nebula is approximately 1 light-year across. That’s fairly big. Consider that Jupiter is located at an average distance of 43 light minutes from the sun. This little nebula is 12000 times bigger than the distance from the sun to Jupiter.
This nebula is high in the northern sky, at a declination of 51 degrees, in the constellation Perseus.
This image was captured in the evening of November 12, 2023 at Lac Teeples. Due to travel, parties and bad weather I haven’t been observing for quite some time. After setting up the equipment I quickly realized that the focus motor was not working. I replaced the power cable, then the USB cable. No dice. I put a small USB heater on the motor (a dew heater for camera lenses) and gave up trying. There is a few inches of snow on the ground and the temperature ranged from around 0 to minus 8 centigrade on November 12, always at 100% relative humidity. This focus motor can work at cold temperatures but the frost was probably messing with it. There is a thick frost on all exposed equipment.
Eventually I realized that I could manually focus the system but it was not easy. I would move the camera a millimeter outward, step back and watch the image form and then assess whether my change made things better or worse. Each iteration took roughly one minute because the telescope needed to settle after I’d touched it. It was around -6C when I was doing this, and I had to do it three times (probably should have done it more often) during the evening because as the temperature dropped the telescope shrank ever so slightly.
Around 11pm, while observing Jupiter, the planet suddenly disappeared. I’d never seen anything like it – there was a glow of light so I just assumed that there was a cloud or trees in the way. I pointed the telescope somewhere else and then realized that the focus motor had suddenly decided to work. It jumped to a different setting, perhaps all those frozen commands were queued up. I was able then to focus the system properly using the motor.
The telescope used was the antique Celestron 14” Schmidt-Cassegrain, ideal for small targets like this. I have been using this scope for the past month – it’s not easy to swap back and forth. I will try it a bit longer, focussing on small targets like planetary nebulae and planets.
Image of M76 captured at Lac Teeples on November 12, 2023 using the C14 Schmidt-Cassegrain and the ZWO ASI-6200MC colour camera. No filters used.
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