Imaging telescopes or lenses: C9.25
Imaging cameras: Moravian Instruments G3-16200 Mark II
Mounts: 10 Micron GM1000 HPS
Guiding cameras: 10Micron HPS System
Software: Seqence Generator Pro · Pixinsight
Filters: Baader Planetarium R 2" · Baader Planetarium G 2" · Baader Planetarium B 2" · Baader Planetarium Baader 1,25" L
Dates:April 15, 2020 , April 16, 2020
Frames:
Baader Planetarium B 2": 7x300" bin 1x1
Baader Planetarium Baader 1,25" L: 14x300" bin 1x1
Baader Planetarium G 2": 7x300" bin 1x1
Baader Planetarium R 2": 6x300" -25C bin 1x1
Integration: 2.8 hours
Darks: ~30
Flats: ~20
Flat darks: ~20
Bias: ~50
Avg. Moon age: 23.12 days
Avg. Moon phase: 39.75%
Bortle Dark-Sky Scale: 7.00
Mean SQM: 18.70
Astrometry.net job: 3425216
RA center: 17h 17' 43"
DEC center: +43° 7' 0"
Pixel scale: 0.514 arcsec/pixel
Orientation: 89.660 degrees
Field radius: 0.405 degrees
Resolution: 4422x3552
Locations: Castenedolo, Castenedolo, Italy
Data source: Backyard
Sometimes even simple errors may be instructive!
This picture of M92 is off center: it seems a simple pointing error, but nowadays pounts are very precise, and SGPRO checks the correct pointing before beginning the sequence so what's wrong?
So, the difference in position is caused by Earth lunisolar equinox precession.
I set in SGPRO the position of M92, got from SkySafary at 2020 equinox (already corrected for precession) but the mount expected Coordiantes at 2000 equinox so corrected (again) for precession.
Result: In this image the off center of M92 is exactly the amount of the precession in 20 years.
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