2021 Stellafane and a little Planetary Image Processing

I first attended Stellafane in 2019 and had a fine time. Last year was canceled due to Covid, but now it’s back and I was eager to check it out for a second time. Stellafane – It’s the 85th Convention of Amateur Telescope Makers on Breezy Hill in Springfield, Vermont.

So after arriving Friday night I set up camp and prepared for a night of camaraderie around the telescope. I wasn’t disappointed! And with the discovery that HAM radio and stargazing go together, this quickly became a stellar gab session of all topics radio, electronics and stargazing!

Vega popped out quite early in the twilight and was quickly followed by Arcturus and Antares. With these three beacons I had my CPC-800 setup and polar aligned in no time. Thin, early clouds quickly gave way to a beautiful night. I had planned to focus on Saturn and Jupiter this trip and perhaps collect some data for later processing.

I always say that – I’m going to collect data for processing. But I never get to the processing part, especially when it comes to planets. I have gobs of old planetary data sitting on my HDD just waiting for its turn.

I just find the processing be a bit tedious, and there’s not a lot of good planetary processing software for the Mac. It’s a shame really – my trusty Mac is quite capable of doing this stuff – except for the tendency for astronomy software to be written for Windoze. And – do I really want to do this on Windoze?! What do you think?

Anyhow, after an unsettled start the atmosphere calmed to decent seeing later in the evening, I did collect some nice image sequences of the two gas giants. These images were collected using my ASI120MCS camera. It’s certainly not a great imaging camera. It’s the camera I usually use for auto-guiding while imaging deep sky objects with my DSLR camera. But the little ASI camera is useful for planetary image captures because I can get relatively high frame rates and because of its small pixel size – a plus for planets which don’t fill much of the telescopes field of view. (I also was using my 2.5x PowerMate for additional magnification.)

Friendly fellow observers gathered round my computer with encouraging words about the live but noisy real-time images. It would be a shame to relegate these to the dustbin of digital storage. “Why don’t I process them!” Maybe because the knowledge that “someday” I’d get to it was enough for me. I generally prefer single, long exposures of dim objects.

Alright – time to fiddle around with SiriL – open-source software that included planetary image stacking capabilities and is available for the Mac.

I’m still learning – else this site would be called “professionalastronomer.org” – but here are a some early results from the data collected that night. I must admit – it’s pretty cool to watch an image finally pop out from the noisy sequence of 2000 video frames.

Notice a sample of the raw data from which the Jupiter image is derived. This shows how the atmosphere affects the views through our amateur ground-based telescopes.

Maybe this will be sufficient stimulus to get me off my butt and processing some of that old data. Stay tuned!

A portion of the original Jupiter image sequence. The image is offset towards the bottom to avoid a dust speck on the cover glass.
A stack of the best 10% of the Jupiter frames
A stack of the best 1% of the Saturn frames

Update: I took a different set of datum from last week and experimented some more with SiriL, this time applying wavelet sharpening and a few other corrections.

I’m getting there. This is a different shot from last week with additional processing.

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