M35 and NCG2158 – Open Clusters in Gemini| 2 images
The other night we had a fluke clear night, and the clear lasted from sunset till after midnight. I had been planning on imaging M78, a beautiful reflection nebula in Orion, however I spent a bit too much time earlier on in the night experimenting with something called plate solving (a wonderful thing that in the long term should help me get set up and imaging much faster each night.) Orion is already right on top of the meridian (the imaginary line bisecting north and south directly overhead) by the time it’s dark enough to start imaging. It moves on towards the western horizon within a few hours, and in less time than that is obscured by trees.
I ended up looking to other objects in the night sky to image. The Pleiades is at a better vantage point, and is an easier subject than most to image, so it was my first target. By the time Pleiades slipped too low to image well, I started looking higher in the sky.
The region of constellations around Orion is rich with interesting objects, especially to the east of Orion. The arms of the Milky Way stretch through that region of sky, right past the eastern side of Orion, right through the western sides of Monoceros, Gemini, and Auriga. Just above Orion’s club, and in western most reaches of Gemini, is a cluster of interesting objects. These include Monkey Head nebula, Jellyfish nebula, as well as two open clusters: M35 and NGC2158. These objects were still up fairly high overhead, above the trees…at least for a while. So I pointed my scope and started imaging.
M35 is a large open cluster that is more dispersed than NGC2158, with hotter, bluer stars. Both reside within the constellation Gemini. It is largely invisible to the naked eye, maybe appearing as a bit of a smudge under very dark skies. NGC2158 is a much tighter cluster, appearing almost globular in nature, and is comprised of cooler stars that are more reddish in color. The overall area these two clusters cover is about as large as the moon in the night sky.
Just to the south by about two moon diameters is Jellyfish Nebula…a faint nebula with an apparent translucence that gives it the general shape and appearance of an actual jellyfish. About two moon diameters to the west of Jellyfish, back in Orion just above his club, are NGC2174 and NGC2175, also known as the Monkey Head Nebula and it’s companion open cluster. Monkey Head is an emission nebula that kind of looks like the head of an ape when observed at the right angle. Monkey Head has some interesting narrow field regions of colorful nebulosity and dark nebula filaments.
The nebula in this region are very faint, requiring more skill than I currently possess to image properly.