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View Full Version : Observation of IRAS 17436+5003 / PN G0.77.1+30.8, a post-AGB (PPNe) object



sudhashn
October 16th, 2024, 06:30 PM
Hello all,

In my recent visit to Hanle (a Bortle 1 location in Ladakh, North India), a cold dry dessert at an elevation of 4300m, (32°47'N 78°58'E ), I tried to observe this Proto Planetary Nebulae in the constellation Hercules (about 1.8° of Eltanin in Draco).

From my voice notes
Located it in the 17mm Baader Hyperion (~90x) eyepiece, looked like a bluish star. Flanked by 2 stars of similar brightness forming an almost equilateral triangle with the object. Needed to go much higher in magnification.
Properly observed with 6.5mm ES eyepiece + 2x Barlow (460x). Did try with 10mm Super Plossl (150x), 6.5mm EP (230x). 230x started showing some nebulosity.
A definite bigger halo, almost circular in shape, was observed. Compared to the halo of nearby two (pretty close to each other) stars, this halo was larger & definitive. Nearby dimmer stars resolved into pinpoint sources too.

As it was a manual scope (with no tracking), I had great difficulty in maintaining the object in the FoV. After 15-20min of struggle, could keep for 20-30s in the FoV to observe properly.

Two accompanying friends (visual observers) confirmed elongation between 1-7O clock positions (in the FoV). However I couldn't observe elongation consistently.

Equipment used : 12" Skywatcher Dobsonian 300mm Flextube Collapsible, manual.
Conditions: Bortle 1 (pristine conditions I have ever observed).
Observation on 30th Sept 2024, 8pm - 10pm.

Other designations: V814 Her, HD 161796 Simbad (https://simbad.cds.unistra.fr/simbad/sim-id?Ident=Hd+161796&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id)query here.

P.S. As I was browsing through Stellarium for objects, usual grid search of 1.5° x 1.5° in Stellarium, found this & noted it down for observation (months before). Interestingly enough, did remember to observe it on the trip too.

Would love to hear from the community on your observations on the same object. Upon research, understood that this is an unique class of object that I have gotten to observe & conditions/friends helped.

Regards
Sudhash

Clear Skies
October 17th, 2024, 01:08 PM
Hi Sudhash,

I took a look at the information you sent and I can not identify an extended, non-stellar object at the position of V814 Herculis. I am quite confident you observed a halo brought upon your optics by that mag. 7.3 star.

Cheers,


Victor

Steve Gottlieb
October 17th, 2024, 10:29 PM
Here's an HST image (https://fox.ncac.torun.pl/postagb2?lang=en&branch=postagb2world&id=2&l=77.133&b=30.87&ctx=hstp), which shows an irregular dust shell elongated N-S, though scattered light from the bright post-AGB star does seem reasonable.

The Torun catalogue of Galactic post-AGB and related objects (https://fox.ncac.torun.pl/camkweb/postagb2.php) has a page on this star here (https://fox.ncac.torun.pl/postagb2?lang=en&branch=postagb2world&id=2&l=77.133&b=30.87) with photometric data and bibliography.