The Cave Nebula (Caldwell 9, Sh2-155, LBN 529) is a diffuse nebula in the constellation Cepheus and about 2,400 light years (ly) from Earth. Sh2-155 is an HII-ionizing region of star formation, much of this activity believed to be triggered by the hot, O-type star, HD 217086.
In addition to the extensive nebulosity in the image, there are numerous Bok globules of very dark dust, star-creation pillars, as well as 2 Herbig-Haro objects in the lower right (see annotation).
Although difficult to discern in the image since there is so much surrounding nebulosity, older photographic images depicted the Nebula’s curved arc of nebulosity that resembled the mouth of a cave. (Patrick Moore is credited with popularizing the name for this emission nebula.) Its arc is more easily seen in RGB images, rather than in images taken with narrowband (Ha, SII, OIII) filters.
Capture Dates: 6/24/24 and 7/13/24
Askar 107PHQ at native fL = 749mm, f/7.0)
ASI2600MM Pro (Monochrome camera)
ZWO 7-position 2" Electronic Filter Wheel (EFW)
ZWO ASIAir with ZWO AM5 mount -- guiding via SV106 and ASI178MM
Filters:
Antlia Pro V series R (60s x 12), G (60s x 12), and B (60s x 12) for RGB stars (0:36)
Antlia 3nm Narrowband SII 2": 33×300″ (2:45)
Antlia 3nm Narrowband H-alpha 2": 15×300″ (1:15)
Antlia 3nm Narrowband OIII 2": 35×300″ (2:55)
Total Integration: 7:31
Pre- and post-processed in PixInsight. Photoshop
A great image of the cave! You’re really nailing these images. I’ve tried this one before but maybe I didn’t get enough signal.. as the result was not nearly as good!
Terri
@terri Thanks so much, Terri! Another image I process multiple times trying to find a version I really liked. This was a complicated one to process, to be sure.
Greg
