The large star cluster in Coma Berenices known officially as Melotte 111, at right, with two of the most prominent galaxies in Coma at left: NGC 4559 at top and the Needle Galaxy, NGC 4565, at bottom. Several other fainter galaxies are in the field, including NGC 4494 between the Needle Galaxy and the star cluster, but looking very star-like at this image scale. I shot this April 11, 2021 on a fairly clear night as a test of the new SharpStar 94mm EDPH refractor telescope and its matching field flattener/reducer. A bit of passing haze added a touch of star glows. There is a version of this same field shot a week earlier in hazy skies with much fuzzier stars. This is a stack of 20 x 6-minute exposures at ISO 800 with the Canon EOS Ra, autoguided on the Astro-Physics Mach 1 mount with the Lacerta MGEN3 stand-alone autoguided set to dither 5 pixels between each exposure. No dark frames or LENR were applied. The field of view is about 3.3° x 5°.
The immensely rich galaxy cluster Abell 1656 in Coma Berenices with two giant elliptical galaxies NGC 4889 and NGC 4874 at its heart. Both are about 11th magnitude. The face-on spiral galaxy NGC 4921 is at lower left at 12th magnitude; the tilted spiral NGC 4839 is at lower right, also 12th magnitude. The field is peppered with dozens of fainter galaxies from the NGC and PGC catalogues, all around 13th to 15th magnitude. The two bright blue stars are 7th magnitude. I shot this on a less than ideal night, with haze moving in, so this is a stack of only 6 x 8-minute exposures at ISO 1600 with the Canon EOS Ra through the Astro-Physics 130mm EDT refractor at f/6 with the 6x7 field flattener. Shot May 5, 2021. Haze prevented more images to smooth the noise more. Autoguided with the MGEN3 stand-alone autoguider.
The Coma Berenices star cluster, aka Melotte 111, at right, with two prominent galaxies at left: NGC 4559 at top left and edge-on NGC 4565 at bottom left. This is a stack of 6 x 8 minute exposures with the SharpStar 76mm apo refractor with the EDPH field flattener for f/4.5 and with the Canon EOS Ra at ISO 800. Diffraction spikes added for effect using Astronomy Tools actions.
