2020 Michael A. Siniscalchi


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Odds n Ends

Messier 92
Globular Cluster in Hercules
RA: 17h 17m 07.39s  Dec: +43 08' 09.4", Distance: 26,700 ly, Size: 14.4 arcmin

Click on image for larger size.
Location & Date
Backyard, Abbott Observatory- Long Island, NY, June 2020
TMB130SS F/7 APO, Moonlite focuser, Losmandy G11 Gemini
Image scale 1.54 arcsec/pixel
Baader L, R,G,B filters
CCD temp -5C
Lum-15x2m & 6x5m,  Red-15x2m & 6x5m, Green-15x2m & 6x5m, Blue-15x2m& 6x5m Bin 1x1
Planning & Acquisition
Image planning - Sequence Generator Pro
Image acquisition - Sequence Generator Pro w/PinPoint & PHD2 (guiding)
CCDStack - calibration, de-bloom, normalize, combine, deconvolution
Adobe CS4 - Image composition, dynamic range blending,  Noise reduction, JPEG conversion

This image is a combination of 2 minute sub-frames to prevent the core from saturation and 5 minute sub-frames to bring out the stars on the perimeter.
From Wikipedia
  Messier 92 (also known as M92, M 92, or NGC 6341) is a globular cluster of stars in the northern constellation of Hercules. It was discovered by Johann Elert Bode in 1777, then published in the Jahrbuch during 1779. The cluster was independently rediscovered by Charles Messier on March 18, 1781 and added as the 92nd entry in his catalogue. M92 is at a distance of about 26,700 light-years away from Earth. M92 is one of the brighter globular clusters in the northern hemisphere, but it is often overlooked by amateur astronomers because of its proximity to the even more spectacular Messier 13. It is visible to the naked eye under very good conditions. Messier 92 has a very low abundance of elements other than hydrogen and helium; what astronomers term its metallicity. Relative to the Sun, the abundance of iron in the cluster is given by [Fe/H] = 2.32 dex,[11] which equates to only 0.5% of the solar abundance.[12] This puts the estimated age range for the cluster at 11 1.5 billion years.