Sh2-200 (HDW 2)

Sharpless 200 (Sh2-200) is a planetary nebula visible in the constellation Cassiopeia. 

This nebula was first discovered by the American astronomer Stewart Sharpless, who included it in the second edition of his catalogue of H II regions (1959) as Sh2-200.

In 1983, it was included in the HDW (Hartl-Dengl-Weinberger) catalogue of planetary nebulae with the number HDW2, but it still remained in the Sharpless catalogue. This nebula is also called the "Bearclaw Nebula".

Its distance has been estimated to be about 3590 light-years, but later studies claim that it is only 1900 light-years away.

This planetary nebula is nearly spherical with pronounced stripes and a darker area to the south, surrounded by a thin fissure. The brighter part of the object has a diameter of about 6' (in the image, north is up).

From the imaging point of view, this nebula is really faint. The image is presented in the Ha-OIII-OIII palette with RGB stars. Total exposure time is about 73 hours (including 5 h for the colour of the stars). As in previous images, the balance of the colours was adjusted to my personal taste with the help of the NarrowbandNormalization module in Pixinsight.  

Click on the image for a full resolution version, or go to the Gallery section for complete exposure details (and a wider field version).

Image processing: Pixinsight.

Observatory automation and remote operation with Talon6