Sh 2-80 "Merrill's Star"

[Uwe Glahn]

Last new moon I tried the WR Nebula Sh 2-80 "Merrill's Star". The nebula is called after Paul Merill, who wrote about the star first at 1938, after Cora Burwill detected an emission line in the yellow portion of the spectrum through the objective prism spectogram on Mount Wilson. It was misclassified as a PN (Min 1-67; PN G050.1+03.3 )

After I few unsuccessful observation I could see something around the 10mag star WR 124. I observed with my 27" under good to very good transparency and tried several AP's and filter. The only successful combination was 172x (AP 4mm) with Hß filter. With that I could see a very dim, round glow with approx 1' in diameter. Brightest part was like a semicircle structure just S of the star. Another better defined part lies very close just E of the star with a short part to the NW.

What experience do you have with this unusual nebula? What aperture is needed to see the faint glow?

250
homepage with inverted version (http://www.deepsky-visuell.de/Zeichnungen/Sh2-80.htm)

[Dragan]

Uwe,

I can't say I've ever observed this.

Where is it? Do you have coordinates?

[Uwe Glahn]

Sorry Dragan, I forgot the coordinates.

SIMBAD says:
RA 2000: 19 11 30.876
DEC 2000: +16 51 38.17

[Steve Gottlieb]

I wasn't successful seeing the disc with a 17.5" nearly 20 years back, but for comparison here is Mike Kerr's observation from Australia (NSW) with a 25-inch:

There are suggestions of a faint halo around the mag 11 star central star at low power without a filter. Another mag 11 star is 1.8' S. The halo is definite at 270x and appears as a very faint mottled 1.5' diameter disk. Two mag 16/17 stars are 40" SE and another mag 16/17 star is 50-60" SW. The nebulosity is brightest around the central star and most obvious in an irregular patch S and N of the central star. There are darker patches in the disk E and W of the central star. No gain with a UHC or OIII filter but maybe a slight gain with an H-beta filter at low power. No useful gain with an H-beta filter at 270x. Best viewed at 270x without a
filter. (30 May 03)

[Jim Chandler]

Interesting. In August 2011 with the 30" f/4.5 at 296x without any filter I saw only a bright star. Adding a UHC brought out a faint, mottled haze around the star.

Jim

[reiner]

This is a very unusual WR shell, as it emits mostly HII and not OIII. I have tried to observe this object several times over the years.

Here are my notes

22" f/4.5
08/2008: unsuccessful
06/2010: suspected as a faint glow around WR star with H beta filter
10/2010: at 350x and with H beta filter, a diffuse glow was observed around the WR star.

Another positive observation was in 2011. During all positive observations, the shell was extremely faint.

[Sue French]

I started trying to see this nebula in 1999, continually failing until 2008. The successful observation was made with a 381/1727mm Newtonian, and the best view was with a UHC filter at 216x. The nebula extended one-third of the way from its central star to the 11th-magnitude star south of it, implying a diameter of 1.2'. An H-beta filter worked, too, but I was getting some light-scatter from it. I could not see any detail in the nebula.
Sue

[reiner]

I re-observed this WR shell again last weekend under alpine skies. This time, I could see the shell already without filter. The H beta filter helped a bit, but not much. Other observers confirmed the presence of the very faint shell without filter. Structures within the shell were there, but I could not pin them down.

[Marko]

Late in chiming in here but finally got to this on a very transparent night of May 25, 2014. I was unable to find it unfiltered or with my trusty NPB filter in my 18" f/3.7 starmaster scope and this was indeed a puzzle as I did not have the nice notes above to indicate I had to use an H-Beta filter. I asked Steve Gottlieb about unusual sharpless objects and he recalled that H-Beta may be required for a few. Lone behold that is what it took on this object. I was able to see glow only around a third to half of the star that I called out as 1/20 fov or 1' long in my 8mm Delos with no paracorr and ONLY with the H-Beta filter. I was not able to see the extension that is shown in the attached drawing made by Uwe that shows a thin blade going around the other 1/4 circumference of the star. Conditions were SQM 21.4 sort of sky at 2:30am with very good transparency.