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View Full Version : Object of the Week - August 20, 2023 - Planetary nebula Henize 1-6 in Vulpecula



Clear Skies
August 20th, 2023, 08:28 AM
This week's OotW is planetary nebula Henize 1-6 (https://aladin.cds.unistra.fr/AladinLite/?target=20%2018%2012.138%2B25%2038%2001.29&fov=0.147&survey=CDS%2FP%2FDSS2%2Fblue), located centrally in the constellation of Vulpecula (https://en.wikipedia.org/wiki/Vulpecula). 30 Minutes of arc east-southeast of the bright variable and double star QR Vulpecula (Burnham 983 (https://www.stelledoppie.it/index2.php?menu=29&iddoppia=87139), A mag. 4.6-4.8).

The nebula was discovered and cataloged (https://iopscience.iop.org/article/10.1086/127642/pdf) by Karl Gordon Henize (https://en.wikipedia.org/wiki/Karl_Gordon_Henize): astronomer, pilot and astronaut who passed away on the flanks of mount Everest. That's quite the resume (https://www.youtube.com/watch?v=unWtrXx7t64).

It's a small nebula, 20"x13" in dimensions, with faint outer regions, lacking a distinct central star. Its northeastern and southwestern edges are brighter, a detail that one ought to be able to pickup visually.

5' PanSTARRS

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Click here (https://clearskies.eu/csog/downloads/dsfootw2023#34) to download the observing guide in pdf.

In the vicinity:
An arcminute and a half to the southeast is the faint double star Pourteau 4342 (https://www.stelledoppie.it/index2.php?menu=29&iddoppia=87508), consisting of a mag. 11.2 primary flanked by a mag. 12.3 secondary. Farther to the northeast, at 21 minutes of arc is Burnham 985 (https://www.stelledoppie.it/index2.php?menu=29&iddoppia=87627). With a large scope the small reflection nebula GN 20.16.2 (https://aladin.cds.unistra.fr/AladinLite/?target=20%2018%2011.793%2B25%2038%2009.07&fov=0.15&survey=CDS%2FP%2FDSS2%2Fblue) southwest thereof can perhaps be glimpsed. As stated in the intro, QV Vul is to the west-northwest: its mag. 7.6 companion can be considered as non-splitable at 0.4", but component C is a wide one, shining at mag. 9.7 with a separation of 116".

As always, give it a go and be sure to report back..!

Uwe Glahn
August 20th, 2023, 10:25 AM
I found an observation and a sketch of the object with my 27-inch.

sketch: 27", 586x, NPB, NELM 6m5+, Seeing III
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home (http://www.deepsky-visuell.de/Zeichnungen/Hen1-6.htm)

Steve Gottlieb
August 20th, 2023, 08:39 PM
My first of two observations of He 1-6 was back on August 8, 1986 with a 13.1" Coulter dob. At the time I was observing planetaries regularly together with Jack Marling and the same night I logged SwSt 1, Cn 1-5, M 1-54, M 1-59, M 1-60, Pe 1-17, M 4-11 and Abell 68, along with IC 1297, IC 4732 and others. This may be the earliest (or one of the earliest) observation of He 1-6.

Using 214x and UHC filter; very faint, small disc about 15" diameter, estimate V = 14.5-15.0. Can almost hold steadily with averted vision. Similar view at 166x with an OIII filter. A small right isosceles triangle of mag 12 stars lies 2' W and a mag 11-12 double star is 1.5' SE.

I made another observation with my 17.5" in July 1999 using 280x and a UHC filter. My notes say it appeared similar in size to the listed dimensions (18" by 13"), elongated NW to SE, but I didn't record any additional details.