nyx tracker

21 Aug 2018

I got my first equatorial tracker mount! I don’t want to spend a ton of money before I have to (cough cough in theory cough), so I bought one of these – it’s a tiny little DIY type equatorial tracker. I had tested it out on a cloudy day and verified it mostly worked, even though I couldn’t see Polaris to align it very well. Last night the skies were clear for the first time in weeks, so despite the Very Bright Moon, I gave it a whirl in the opposite direction. Since I was mostly just testing the functionality of the tracker, I used a Jupiter-9 85mm – partially because it’s relatively light, fast and long, and partially because I was morbidly curious how bad it’d look (narrator voice: very bad).

I just pointed it randomly in the sky away from the moon, so nothing of note necessarily – but astronometry knows what it is. So as you can see there’s quite a bit of light pollution and noise, but still: the center stars are (mostly) stable! The stars on the periphery suffer badly from coma, due to my poor choice in lenses. This was my first chance to learn more about processing photos as well: specifically, the value in using flat frames to correct for lens vignetting/fall-off (in addition to dark frames) when stacking. Not particularly amazing results, but good confirmation that the gear works and some processing experience under my belt!

• Camera: Sony A7S II
• Lens: Jupiter-9 85mm f/2.0
• ISO: 125
• Shutter Speed: 2”
• Aperture: f/4
• Total Exposures: 100
• Dark frames: 30
• Flat frames: 20
• Software: DeepSkyStacker and Darktable for levels adjustment