Never never thought I would get this image, but thanks to re-engineering and raising the pier I can see lower at the horizon down to 12 degrees. I did have to trim my Olive trees further and it is only visible in the 10 DEG arc of azimuth.

This is the lowest of the Sharpless2 Objects.

I put up several images including the original which is best plate solved for some reason in the PI system and identifies the PN at the right. The Sh2-4 itself is pretty much beyond this frame.

From GalaxyMap:

Infrared imagery reveals that RCW 121 (Sh 2-4) and RCW 122 lie at the edge of an enormous bubble ionised by the star cluster Havlen-Moffat 1. This cluster is 2-4 million years old and contains the Wolf-Rayet stars WR 87 and WR 89 as well as several O-stars.

GENERAL NOTE ON SHARPLESS2 OBJECTS>>>>>>>>>>>>>

I have been on a project for several years now to image all the Sharpless2 Objects that I can see from my location near San Francisco. I chose these because they are visible in light polluted areas. These objects generally represent left over Hydrogen along the edge of the Milky Way that has gotten molded into interesting shapes.

There are 313 Sh2 objects.

As of the date when this image was posted:

I had imaged 256 (82%).

There are 12 too diffuse/large to image with my set up (Sh2 111, 117, 122, 131, 132, 145, 178, 218, 221, 230, 268 and 310).

There are 5 that are never above 14 DEG elevation at my site and are too low for my 15 DEG min due South (Sh2 2-6) [Edit 7/12/21- I can get these now with pier upgrades].

This leaves me 41 potentially still do-able and most are in Expert Scheduler waiting for them to pass by.

The first one was taken on December 23, 2013.

Many were taken with my old Tak 180 ED, which had a wide field of view, but was replaced with my Stellarvue 130, which is more narrow field. I have also taken two very wide field HA images with my Nikon D800 and a 50mm lens.

This is my collection:

Sharpless2

Wide-Angle Hydrogen Alpha Nikon Image Sh2 79-171

Please note there is also a Sharpless2 Group with now more than 1500 examples.

Sharpless2 Group

Other useful links include:

Gary Imm's Collection

GalaxyMap's Collection

The Sharpless Catalog

The MDW H-alpha Sky Survey

Reiner Vogel's detailed observing catalog

Hope you enjoy these obscure but interesting objects...