17.5: A controversial object, Sharpless 2-155 in Cepheus, is dubbed the "Cave Nebula". Patrick Moore undeservingly dignified this faint HII region in his "Caldwell Catalogue". You have to seriously question whether he ever viewed this difficult object! It was best seen in my 17.5" at 100x as a large, diffuse glow mostly surrounding mag 8.5 SAO 20334 (22 56.8 +62 37) and extending north towards mag 7.6 SAO 20335 located 7' due N. I tried using OIII and H-Beta filters but neither provided a noticeably improved contrast. The only structure visible was a very small knot less than 3' ENE of the mag 8.5 star. At 220x this locally brighter spot was clearly seen as a faint 1' roundish glow. This may be an interesting object photographically but visually it is a challenge just to view. - Steve Gottlieb
