Sangamon Astronomical Society

Binocular Double Star Observing Program

https://www.astroleague.org/binocular-double-star-observing-program/

Effective Binocular Observing ...
Binoculars must be precisely focused.
Binoculars must be held steady. Mounted on a tripod is best.
Adequate dark adaption is needed. Wait at least 15 minutes in the dark before meaningful observing begins. 30 minutes is better.
Glare from a bright primary interferes with spotting a dim secondary. The greater the magnitude difference, the greater the difficulty splitting them.
Steady atmospheric seeing is desired.
Best observed when the double star has an altitude higher than 30º.

Coma Berenices Open Cluster
aka Melotte 111

Easily visible in the early evening from mid March through July.

The two-dimensional celestial dome is deceiving in regard to the true spacing of stars in three-dimensional space.

Melotte 111 is thought to have over 40 stellar members, most being below naked eye visibility down to 9th and 10th magnitude.

The galaxies shown are typically 150,000 times farther than the Coma Bernices Open Cluster (Melotte 111).

Gamma, the brightest member, is not a true member of the cluster, but a foreground star.

The brighter stars of the cluster are on the order of 10-20 light-years apart from each other.

The volume is filled with 5 times as many stars as shown, but most of those are fainter than 8th magnitude.