|Object name:||Constellation:||Coordinates:||Apparent size:||Visual brightness:|
(= NGC 6341)
|Hercules||17h17m / +43°08'||14.0'||6.3 mag|
The globular cluster Messier 92 (NGC 6341) in the constellation Hercules. The cluster is 26,700 light-years from earth, measures 109 light-years in diameter, and was discovered by the German astronomer Johann Elert Bode in 1777 and inadvertently rediscovered by French astronomer Charles Messier in 1781. It has little of the elements other than hydrogen and helium; astronomers term this low metallicity. (source: Wikipedia).
One hundred thirty-five 1-minute exposures (135 minutes total exposure) at gain 100 and -10°C, taken on May 26 / 27, 2023 and on June 17 / 18, 2023, were added for this shot with Astro Pixel Processor (APP) software and the final image processing was done in Photoshop. Darks, flats, bias, and darkflats were used.
Equipment: Cooled ASI 2600MC Pro camera, TeleVue Paracorr Type II coma corrector, 16" f/4.5 "Ninja" dobsonian telescope riding on a dual-axis Tom Osypowski equatorial platform, Lacerta MGEN autoguider, Lacerta off axis system (field of view comparison: image of the moon with the same equipment).