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Wednesday, November 9, 2016

A rare image out of the planetary nebula in Cassiopeia, KjPn8 (PN G112.5-00.1)

Few year back I added this small target in Cassiopeia to my imaging plan. Now we had few clear nights and I was able to finalised a new photo out of it. This is a very dim target and it located just next to famous Bubble Nebula. Total exposure time was around 11 hours for Ha and O-III.

PN G112.5-00.1
Click for a full size photo

Image is in natural colours from the emission of ionized elements, H-alpha and O-III.

An experimental starless version to show the actual PN better

A bright spot at the centre of the planetary nebula KjPn8 is the central disk (Diameter 4 arc seconds).

A two frame mosaic with the Bubble Nebula
Click for a full size photo

I shot the Bubble Nebula part of the mosaic back in 2012


KjPn 8 (PLN 112-0.1) is an unusually-shaped (14' x 4') planetary (PN) nebula located in the Constellation of Cassiopeia at RA 23h 24m 10s and DEC +60d 57m 30s. It is partially embedded in hydrogen nebulosity from the often-imaged Bubble Nebula complex (NGC 7635, Caldwell 11) and the open cluster, M52, located off the upper right side of this image. North is up and the field is ~ 35' x 35'. Lopez et al. (Astrophys. J, v538, 233-240, 2000) describes KjPn 8 as an "extreme polypolar planetary nebula with a large scale structure characterized by a giant biconical envelope". Steffen and Lopez (Astrophys. J. v508, 696-706, 1998) suggest that the strange tubular structure results from the action of a bipolar, rotating episodic jet whose direction has changed with time. The radial velocity measurements suggest a distance of ~5,200 light years. They suggest that it formed from two distinct and consecutive PN-like events starting with a binary core have stars of similar mass. One event led to the very long structure (NW-SE). The other (NE-SW) extends between the bright pinkish lobes that are enriched in OIII. They further suggest that KjPn 8 may be a rare object in the Milky Way Galaxy. (Source, )


The location of PN G112.5-00.1 is marked with a white circle to this mapped colour image of the area. This is my older wide field photo, more info about it can be seen HERE

Technical details

Processing work flow

Image acquisition, MaxiDL v5.07.
Stacked and calibrated in CCDStack2.
Deconvolution with a CCDStack2 Positive Constraint, 33 iterations, added at 25% weight
Color combine in PS CS3
Levels and curves in PS CS3.

Imaging optics
Celestron Edge HD 1100 @ f10 with 0,7 focal reducer for Edge HD 1100 telescope

10-micron 1000

Cameras and filters
Imaging camera Apogee Alta U16 and Apogee seven slot filter wheel
Guider camera, Lodestar x2 and SXV-AOL

Astrodon filter, 5nm H-alpha
Astrodon filter, 3nm O-III
Astrodon filter, 3nm S-II

Exposure times
H-alpha, 21x 1200s = 7h
O-III, 12 x 1200s binned = 4h 
Total 11 h

A single uncropped, calibrated and stretched 20 min H-alpha frame

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