Celestial hemisphere:  Northern  ·  Constellation: Hercules (Her)  ·  Contains:  M 92  ·  NGC 6341
M@H 92: Damned precession!  a city view of M92, Edoardo Luca Radice (Astroedo)
Powered byPixInsight

M@H 92: Damned precession! a city view of M92

M@H 92: Damned precession!  a city view of M92, Edoardo Luca Radice (Astroedo)
Powered byPixInsight

M@H 92: Damned precession! a city view of M92

Equipment

Loading...

Acquisition details

Loading...

Description

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.

Comments

Sky plot

Sky plot

Histogram

M@H 92: Damned precession!  a city view of M92, Edoardo Luca Radice (Astroedo)

In these collections

Messier at Home