The autumn Milky Way offers the opportunity to photograph many wonderful celestial objects in the northern hemisphere. Most often, the attention will focus mainly on the most prominent objects, such as the Double Cluster in Perseus, the Heart Nebula, the California Nebula, etc. However, many other wonderful celestial objects shine in the autumn Milky Way. For example, in the constellation Cassiopeia - like so many jewel boxes, - smaller open clusters are really bustling. We can easily make sure this if we scan the region of Cassiopeia with binoculars under dark sky.
Such wonderful jewel boxes are also the NGC 654 and NGC 663 open clusters, which are approximately 1° apart. The pair is visible at 2-2.5° from the star δ Cass, and about the same distance from the star ε Cass.
NGC 654 (at left side) is a young, 14-15 million years old open cluster with about 80 members. (It is the same age as the famous Perseus twin cluster.) It was discovered by William Herschel in 1787. The distance of the cluster is about 6,600 light-years from Earth but according to other descriptions its distance is 7,800 light-years from us. Its diameter is about 14 light-years. The cluster consists of 10-14 magnitude stars, but its brightest star is 7 magnitude.
There is a very faint reflection nebula, vdB (van den Bergh) 6 in the southwestern side of NGC 654 cluster. This nebula is hard to observe because of its faint and many bright stars around it. Like all bluish reflection nebula, it is also illuminated by a star. In this case the star is a blue, supergiant star (BD+61315).
We can see another kind of object in the northeast direction from the open cluster. LDN (Lynd’s Dark Nebula) 1337 is a large, elongated dark nebula. We can see other two slightly smaller dark nebulas (LDN 1332 and LDN 1334) above the previous one.
NGC 663 (at lower right) – which known also as Caldwell 10, - is an open cluster with about 400 stars. Its diameter is about 10 light-years, and its distance is about 2,500 light-years from Earth. The apparent brightness of this young cluster is 7.1 magnitude.
I collected photons more than 8 hours (two short nights on 12th November and 3rd December, 2023) under dark sky (Bortle 3) in Hungary.