This image captures 4 seldomly imaged faint Sharpless HII emission objects located in the constellation of Cepheus at a declination of +59 degrees. All of these nebulae feature brightly outlined dramatic clouds.
The broad emission area across the top right half of the image, and the only one not identified on the Astrobin mouseover, is Sh2-134:
Sh2-135 is just below and right of image center:
Sh2-138 is the tiny object towards the lower left corner:
Sh2-139 is in the lower left corner:
I have previously imaged several of these objects with my longer (and slower) focal length systems (
Sh2-135 and
Sh2-138), but the results were poor, requiring much more time than I used.
Distance measurements to these faint nebulae indicate that the emission regions on the right side of the image are about 3000 light years away while the smaller regions on the left side are about 10,000 light years away, such that all of these regions are somewhat similar in actual size.
This image uses a HII-SII-SII palette for the nebula, with RGB stars. I also collected OIII and initially used the SHO palette in my processing, but the OIII signal is basically non-existent and the resulting image was not interesting using that palette.
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