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Getting plate-solving status, please wait...


            Joel Shepherd


Technical card

Resolution: 1280x1013

Dates:May 6, 2017May 8, 2017

Baader Planetarium B 1.25": 15x120" bin 1x1
Baader Planetarium B 1.25": 20x30" bin 1x1
Baader Planetarium G 1.25": 15x120" bin 1x1
Baader Planetarium G 1.25": 20x30" bin 1x1
Baader Planetarium R 1.25": 15x120" bin 1x1
Baader Planetarium R 1.25": 20x30" bin 1x1

Integration: 2.0 hours

Avg. Moon age: 11.65 days

Avg. Moon phase: 88.61%

Bortle Dark-Sky Scale: 6.00 job: 1576480

Locations: Home, Seattle, WA, United States

Data source: Backyard


Subject: M3 in Canes Venatici. Roughly 34000 light-years distant, 180 light-years across, containing a half-million stars and somewhere between eight and eleven billion years old.

Capture notes: Taken with nearly a full moon in the sky, but as Seattle's worst winter in recorded history (122 years) loosens its grip, who is to complain? This was my first attempt to get my (new) 8" EdgeHD and (new) AP Mach1 mount to work together. The first night I failed to polar align, so settled for 30-second unguided lights. The second night was short but much better: guiding with 0.5"-0.6" RMS error, which seems pretty good to me.

Processing notes: I didn't have time to take luminance and synthesized it from the RGB stacks. The stacks were surprisingly low noise, particularly given the moonlight. Is noise somehow related to focal length and pixel size, or was it the sheer number of lights (35 per stack)?



Joel Shepherd
License: Attribution Creative Commons




            Joel Shepherd

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Images from the EdgeHD Series