Tammy Plotner and Jeff Barber, Universe Today
Today in 1852 J. L. K. Dreyer was born. It was this Danish astronomer who compiled the New General Catalog (NGC) published in 1878. As a professional astronomer, Dreyer began his observations of the night sky as an employee of Lord Ross at Beer Castle in Ireland. Later Dreyer moved to the Armagh Observatory where he confirmed many of the studies about the deep universe carried out by William Herschel and other observers using a 10 inch diameter telescope for the purchase of which he raised funds.
Even with the variety of astronomical catalogs available today, the NGC itself, and the abbreviated list of their descriptions, is still widely used.
Even today we will observe the moon when the crater of Copernicus will be visible to the night eye even to the owners of the most modest optical equipment. In small binoculars, Copernicus is seen as a bright ring halfway along the dividing line between light and dark. Telescopes reveal the perfect central peak at 120 meters in diameter of the Copernicus Crater which has a total diameter of 97 kilometers. Copernicus has a strong presence as a remnant of a giant meteorite collision. Its depth is 3,800 meters and its walls are 22 kilometers thick. Over the next few days, more impact rays from the acquiring crater will reveal themselves and become a wonderful presence.
And now for something impressive from Dreyer's work. We will turn our eyes, binoculars and telescopes to Orion's belt and the bright open cluster NGC 1981. On a dark, moonless night, this cluster can be seen by the naked eye as a stain on Orion's sword.
Using binoculars or a telescope you can see how 1981 fits into the environment. Do you see the three 6th degree stars at the top of the cluster. They are part of the cluster.
Now look south towards 42 Orionis, a beautiful double star to see. Try to observe the double system Lute Orionus. After the low-power observation, look at the stars at the top of the list in a telescope and you'll also see about a dozen scattered young, hot, bright stars that make up cluster number 1981 on Dreyer's sky list.
https://www.hayadan.org.il/BuildaGate4/general2/data_card.php?Cat=~~~393513569~~~261&SiteName=hayadan
