80mm finder (6/7/08): using 25x and an OIII filter, the brighter northern side of the shell was clearly visible and appeared locally brightest in an elongated arc on the north side passing through mag 7.2 HD 192182. A very faint hazy glow with no structure completed most of a large oval.

William Herschel discovered NGC 6888 = H IV-72 on 15 Sep 1792 (sweep 1027) and recorded "8m. Double. A faint milky ray south preceding joins to the double star; it is about 8' long, and is 1 1/2' broad." His position is within the interior of this Wolf-Rayet shell, but Bigourdan's corrected RA from 18 Oct 1895 (copied to the IC 2 notes) matches the brightest arc. Dreyer made three detailed observations and a sketch using the 72", which was published in plate V of the 1880 publication "Observations of Nebulae and Clusters of Stars".

NGC 6888 is illuminated by the Wolf-Rayet star

HD 192163 = SAO 69592 at 20 12.1 +38 21. This emission star was "discovered" spectroscopically by Copeland while sweeping with a Secchi prism at Dun Echt, Aberdeen and listed in MN 45, p91. Copeland noted "this is the 7.1 mag star DM +37°3821. It has a spectrum of several bright lines near D, and a very bright band in wavelength 464 mmm."

As far as the nickname "Crescent Nebula", in the 1920 Mt Wilson observations (based on 60" plates), Francis Pease description reads: "It is roughly elliptical, 18'x9', p.a. 42°. The N, Np and Sp edges include the bulk of the nebulosity, which gives it a crescent form, the bowl of which is filled with faint and scattered nebulosity."

100/150mm - 6" (8/23/03): used a 6" off-axis mask on my 18", along with a 31 Nagler (73x) and an OIII filter. A faint curving arc was visible which begins SW of the mag 7.2 star on the north edge and curves around to the mag 8.2 star on the NE side, extending nearly 90° of arc along the annulus of the Crescent Nebula. No other nebulosity was visible.

200/250mm - 8" (9/7/18): used an 8" off-axis mask on my 24-inch, along with a 31 Nagler (84x) and an OIII filter. I was surprised how much of the ellipse could be easily traced -- perhaps 240°, extending clockwise from mag 8.2 SAO 69611. The most prominent section is the piece SW of mag 7.3 HD 192182, but the thick section at the SW end with a somewhat lower surface brightness was easily seen.

8" (8/9/80): faint, elongated arc of nebulosity connecting two mag 7.5/8.5 stars and extending SW of the brighter star. Set in a very rich star field. Only the brightest portion at the north end of the nebula was noticed.

300/350mm - 13.1" (9/6/81): bright, large, oval shell, nearly complete loop visible with UHC, striking unusual appearance!

400/500mm - 17.5" (6/29/00): Stunning view at 100x (20mm Nagler) using an OIII filter. The outline appeared as a huge, irregular cosmic egg, ~18'x11', floating in a very rich Cygnus star field. The complete annulus as easily visible. The brightest section is along the north side and passes through a mag 7.2 star (very unequal double) at the north edge. This piece displays much structure with several knots and wispy tendrils. The interior has an irregular surface brightness with wispy striations that appear to radiate from the mag 7.4 Wolf-Rayet central star towards the NW rim at the end of the bright arc. The rim is widest on the SW end with more nebulosity filling in towards the center, including an isolated bright knot that is on a line passing through the mag 7.2 star on the north end and the central star. The fine texture and structure of the nebulosity creates an "electric" effect with a 3-dimensional sense.

17.5" (7/5/86): the "Crescent Nebula" is one of my favorite large nebulae at 100x with a OIII filter (excellent contrast gain). Appears as a bright, 16'x11' oval or egg-shaped annulus elongated SW-NE. The rim is virtually complete except for a small piece of the east side and exhibits a great deal of turbulent, wispy structure. The rim os brightest just SW of mag 7.2 HD 192182 (unequal pair O∑ 401 = 7.2/10.5 at 14"), which is embedded in the rim at the north end. The nebula also passes through mag 8.2 SAO 69611 on the NE side. Just north of center in the interior is the mag 7.4 Wolf-Rayet star HD 192163 = W-R 136, whose strong stellar wind created this shocked ring-type nebula. This is beautiful nebulosity set in a very rich Milky Way field.

600/800mm - 24" (9/7/18): absolutely gorgeous view of this huge cosmic bubble at 124x (21mm Ethos) and OIII filter. The entire very irregular oval outline was easily visible and full of wispy structure and wide variation in brightness levels. Two bright stars are involved along the rim; mag 7.2 HD 192182 (unequal double STT 401) in the center of the northern quadrant and mag 8.2 SAO 69611 on the northeast edge (7' separation). The sharpest curve in the annulus is the section connecting these two stars. Moving clockwise from these two stars, the highest surface brightness section of the nebula is a linear strip extending southwest of HD 192182. Mag 7.4 WR 136 (HD 192163) is nearby in the interior, 5.4' SSW of HD 192182. Very patchy nebulosity connects in a triangular wedge from HD 192163 to the western side of the rim, very close to the highest surface brightness section. Continuing clockwise, the annulus brightens on the southwest edge and spreads out (thicker annulus). This section is highly structured, though has a lower surface brightness on the inside edge. A fairly prominent "knot", at least 30" diameter, is within this pool of nebulosity on the south side, on a line with HD 192182 and W-R 136. Continuing clockwise, the irregular annulus is weakest on the southeast facing portion of the rim. The surrounding Milky Way field is plastered with bright and faint stars with a large number within the confines of the nebula.

900/1200mm - 48" (5/3/19): at 287x and NPB filter; I was amazed by the interior filamentary structure, particularly in the southern half that was not previously observed. I was surprised the nebulous filaments that connect the central mag 7.4 Wolf-Rayet star to the western rim continues SE of the star in a well defined, distinctive filament to the dim eastern rim.

Notes by Steve Gottlieb