Any positive or negative observations of WDHS 1?

Last new moon, I tried to observe WDHS 1 (Weinberger, Dengel, Hartl, Sabaddin 1) or WeDe 1 in Orion, one of the largest known PNe (22'). This is a tough object and I had tried to observe it before with negative results. Coordinates are 05 59 24 +10 41 40, size is 22'x17'

Here is a DSS image of the PN
Attachment 546

Here is an inverted image
http://www.reinervogel.net/LargePN/images/WDHS-1inv.jpg

After some time at the eyepiece of my 22" with 7mm exit pupil and OIII (the red color is mostly NII), I suspected an extremely slight brightening at the location of the PN. At the nortern edge, the faint glow appeared round, though there is one of these deceiving star chains that make you believe everything :-). I would have thought that this is mostly averted imagination, but the southern edge appeared to be straight at times, like an oval with a cut off end. The other day, I looked at a recent image by Stephane Zoll, that showed a somewhat similar structure.

Andru, a co-observer, was quite unconvinced of seeing anything at the location, so I am quite uncertain about this observation. From my memory, I would put it in the same ball park as PuWe 1, maybe a tad more difficult (skies were about 6m5 this night and a bit better when I observed PuWe1).

Has anybody of you observed or tried to observe this large PN? Maybe someone can even compare it to one of the other large PNe?

Negative Reiner.

I tried the PN 4 years ago under good to very good transparency with my 16" and 69x (AP 5,8mm) + [OIII]. I noticed: "difficult and rich star field full with dangerous chains and knots; PN definitely not seen".

Hi Rainer and Uwe,

I tried this one several years ago under 6mag skies @home- no success (the same negative result as PuWe 1). These stinkers require excellent transparency under true dark skies. Maybe next time under La Palma skies...

A buddy of mine (of us), Frank Richardsen, reported a positive observation using his 20" : a weak glow in rich starfield, arc suspected. See my website.


regards, Jens

Thanks Uwe and Jens,

I hoped for some direct comparison to PuWe1, as I had observed PuWe 1 with certainty last year together with Matthias Kronberger from Schauinsland mountain next to where I live. Thanks also for the mention of Frank's observation. I'll ask him.

If it's any data point, my friend John showed me Sh2-216 (1.6 deg) a couple times through his 25". The brightest edge was visible. These objects are probably much fainter?

Quote:

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Originally Posted by akarsh

These objects are probably much fainter?

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Yes, WDHS 1 is much fainter than Sharpless 216.

But that is only half the story.

As you mentioned, Sharpless 216 has a diameter of well beyond 1 degree, which makes it a difficult target for large dobs (at least for me). I usually have a hard time seeing Sharpless 216 unambiguously with my 22" and often fail seeing it at all. With my 80 mm finder (equipped with filter), I found Sharpless 216 to be a faint, but visible object, better than with my large telescope. On the other hand, I would never bother trying to see WDHS 1 (or PuWe 1 or one of the other "semi-large" PN) with my little refractor.

Hi Reiner,

When I observed Abell 21, I also tried WDHS 1 (WeDe 1) - same night, same conditions. The observation was inconclusive. I would not dare say that I saw a very faint glow at the position with a round shape. On the other hand, I would not rule it out either. For comparison: Later that night I also tried EGB 1, and in this case I definitely saw nothing. If WeDe 1 is fainter than EGB 1, then the weak glow was an illusion probably caused by star chains. I will try both objects again under better conditions.

Greetings
Johannes

Hi Johannes,

I have never tried to observe both EGB 1 and HDW1 the same night, so I have no direct comparison. But from my memory, I would say that EGB 1 should be brighter and easier than HDW1.