Ausschnitt im Sternbild


Old planetary nebula in the constellation Cassiopeia.

HDW 2 (Hartl-Dengl-Weinberger 2), also known as Sharpless 2-200 or PNG 138.1+04.1, is a quite old planetary nebula (PN) in the constellation Cassiopeia at RA 3hr 11m 29s and DEC +62d 45m 5s. The nebula is also called "Bearclaw nebula".
The bright part of the object has a diameter of about 6', north is at the top left.

HDW 2 / Sh2-200
Please click on the image for a bigger view.
Object: HDW 2 / Sh2-200
Date of exposures: 22.11.2017, 23.11.2017, 25.11.2017, 07.01.2018, 08.01.2018
Exposures: 38 hrs.
Telescope: Takahashi Epsilon 130D
Focal length: 430 mm
Filter: Astrodon H-Alpha 5nm, OIII 3nm, RGB E-Series
Camera: Atik 460Exm
Guiding: Off Axis Guider, Lodestar
Mount: EQ8

According to W. A. Weidmann and R. Gamen, who have examined the central stars of different PNs, the central star of HDW 2 is a binary star.
The color of the object is a mixture out of blue/green OIII and red/magenta Ha. The Planetary Nebula is almost spherical with pronounced stripes and a darker area to the south, surrounded by a thin fissure. What looks like an outer bright H-Alpha ring or halo is probably the edge of an extended spherical envelope from another previous explosive event. This weak halo reaches to a small open cluster of stars, Trumpler 3.

Frank Iwaszkiewicz ( and I have once again joined forces for a cooperation project for this extremely weak representative. The version shown above corresponds approximately to the field of the Epsilon.


Smaller field of my 10" Newtonian:




Frank Iwaszkiewicz:
- 10", f4 Newton:
Ha: 18 x 1200"
OIII: 29 x 1200"
RGB: 24 x 300"

17,5 Std.

Jens Zippel:
- 10", f4 Newton:
Ha: 33 x 900"
OIII: 22 x 900"
RGB: 27 x 300"

16,0 Std.

- Takahashi Epsilon 130 D, f3,3:
Ha: 4 x 900"
OIII: 6 x 900"
RGB: 30 x 240"

4,5 Std.


The exposure session in my videoblog ...



bezeichnung - annotiert