Best Abell Planetaries: Spring

Observing Notes by Steve Gottlieb

Abell 31 in Cancer

17.5: this giant planetary was best at 83x using an OIII filter. Fairly faint, easy with averted vision, almost round but edges not sharply defined. Two mag 10 and 11 stars either involved or just off edges, three other mag 10-11 stars nearby form a parallelogram enclosing the planetary with sides 11'x8' oriented N-S and WSW-ENE. Located 30' N of O_195 = 7.5/8.0 at 10".

Abell 33 in Hydra

17.5: at 105x with an OIII filter appears fairly faint, very large, diffuse, slightly darker center (partially annular). This planetary has a mag 7.2 star ( SAO 137026) embedded in the SW end! Appears brighter along an arc on the W side and N of the mag 7 star.
13: faint, very large, slightly elongated ~N-S. There is a bright mag 7.2 star at the SW edge and a faint star at the NW edge. Has a brighter rim at 62x to 79x using an OIII filter. Visible with direct vision.

Abell 36 in Virgo

13: at 62x with UHC filter; unusually bright mag 11 central star surrounded by a fairly faint, fairly large, round, diffuse halo. Slightly better contrast with UHC filter than OIII.

Abell 37 in Virgo

17.5: faint but easily picked up at 100x without filter as a moderately large, round disc less than 1' diameter. Nicely enhanced with OIII filter and appears moderately bright, crisp-edged and slightly elongated N-S, 45"x40". Also nice view at 100x with UHC filter. Located 6.7' S of mag 9.4 SAO 158326.
13: at 79x and OIII filter appears fairly faint, fairly small, round, with an even surface brightness and sharp edges. Faint but visible without filter. Easily takes 166x with a UHC filter. No central star seen with or without filter.

Abell 39 in Hercules

17.5: large but little-known 3' planetary in Hercules. Picked up 100x using an OIII filter sweeping the field. Once identified it was visible continuously with direct vision as a round, sharp-edged disc which was slightly brighter on the following edge. The planetary was even faintly visible without a filter and several faint stars were seen to be superimposed.
13: faint, fairly large, round. This planetary can just be held steadily with averted vision using an OIII filter which provides a superior view to the Daystar 300.

Abell 43 in Ophiuchus

17.5: nice view at 100x with OIII filter where it is easily visible continuously with direct vision. The disc is at least 1' in diameter, appears slightly elongated and has crisp edges. At 220x , faintly visible without filter and quite noticeable are two superimposed mag 13 stars oriented ~N-S with one at the N edge (check) and second star near the center. A very faint star is also visible near the (SE) edge. Estimate V = 14.0.
13: at 79x and OIII filter; faint, moderately large, almost round, estimate V = 14.2. Can barely hold steadily with direct vision but easier with averted. Located 4' SE of a mag 9.5 star. Collinear with a wide pair of mag 11.5-12 stars about 3' SE.