Lorenzo Comolli's Astronomy HomePage

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This is a very faint planetary nebula in the Lynx constellation. Its name PK is due to two astronomers, Perek and Kohoutek, while the number 164+31 is the galactic coordinates in longitude and latitude; finally the ".1" is a progressive number, useful if any other object at the same coordinates is found. The object was discovered by Jones and Emberson, and that's why another name is Jones-Emberson 1.
The diameter is 6' and the magnitude 14. The foreground field is filled with small galaxies: the larger ones are PGC 2439677 (mag. 15.6, 6' East) and PGC 22186 (mag 13.6, 22' Ovest). Moreover a couple of other galaxies are behind the nebula, and their light is filtering trough.
The central star shows a strong blue color. According to USNO B1 catalog (POSS-II) the magnitude of the star 1434-0192502 is 16.1 in blue and 17.4 in red.

Here is a crop of the central region. I cannot find the name of the tagged galaxies. Can anybody help?

Technical Data
Optics	Newton 200 mm (homemade by L. Comolli, F. Riccio and P. Battaglia)
Focal Lenght	1260 mm
Focal Ratio	f/6
Corrector	Baader MPCC
Exposure Time	4h20m (single exp of 10 min)
CCD	Canon EOS 5D with baader filter
Sensitivity	800 ISO
Location	Bogli (PC, Italian Appennines) at 1350 m height
Date	1-2 April 2011 (two nights)
Mount	Gemini G-41
Tracking	Lodestar on an 80mm f/5 refractor
Temperature and humidity	T= +8°C, RH=40-50%
Sky brightness at zenith (with SQM-L)	21.2-21.4 mag/arcsec^2
Notes	Very faint object to image with a DSLR. The single exposures show only a noisy patch of nebula. Some wind made the guiding inaccurate and the stars less than perfect. Thanks to Daniele Cipollina for some hints about processing.