Moonrise, Charlotte, North Carolina
2021/06/25. (revisiting 2018/05/01)
I made this photo using a TMB 92SS refractor (telecompressed to 402mm) and a Canon 6D during a residency at Wild Acres in 2018 where I was working on a project which is still creeping toward completion. On May 1, the barely-beyond-full Moon rose just before 10:00 PM a few degrees north of Charlotte, North Carolina, as seen from Stepps Gap adjacent Mount Mitchell State Park. City center is 89.2 miles away and 5,380 feet lower. I just lately got to talking about the geometry of that shot with some neighbors and thought it well past time I worked up a good image from the night's take. I was really up there to determine how to measure the azimuth of the rising Moon given such severe refraction and deep (for non-aviators) depression of the horizon. Anyway, I lined up three images made about 4m30s apart with the lights of Charlotte in a fourth and composited them. There's a ton of atmospheric extinction involved; a typical and useful exposure for Charlotte was 4s, ISO 800, at F4. That also works for the very low Moon but is too long after the Moon gets up a bit. It's not a simple problem.
There is a lot of refraction. Note that not just the shape of the rising Moon but the alignments of the consecutive images change. The lowest two do not align with the upper images. The very low, highly refracted rising Moon "scoots" sideways a tidge as it moves through the first degree or two above the horizon, then things get more familiar.
Later that same night:
28mm. Jupiter at top.
TMB92SS, 10s, ISO 3200.
My deep-sky photos are made with a variety of sensors and optics. Deepest images come now from a ZWO ASI1600MM Cooled Pro CMOS camera, an ASIair (model 1) and sometimes one of several laptops. A good many images come from an unmodded Canon 6D but a lot more will be coming from an R6. Video and video extracts begin in a Canon EOS M, usually running in crop mode via Magic Lantern firmware (but the 6D and especially the R6 will probably see more use). Telescopes include an AT10RC, an Orion 10" F4 Newtonian, and a pair of apochromats: a TMB92SS and a AT65EDQ. A very early Astro-Physics 5" F6 gets some use, too. So do lots of camera lenses on both the ASI1600 and on the Canons. A solar Frankenscope made using a 90mm F10 Orion achromat and the etalon, relay optics, and focuser from a Lunt 60 feeding a small ZWO camera will see more action as the Sun comes back to life (Autostakkart!3 is my current fav for image stacking). Mounts include an iOpton SkyTracker (original model), a bargain LXD-55, a Losmandy G11 (492 Digital Drive), and an Astro-Physics Mach1. PixInsight does most of the heavy lifting; Photoshop polishes. Some of the toys are more or less permanently based in New Mexico. I desperately hope to get back soon.
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