Elevation 800 m, telescope D = 0.5 m, F = 2 m. Sky 21.31 mag/sq arcsec, seeing 0.5-1.0 arcsec. Abell 21, planetary nebula, Gem. Visible without a filter in a 13 mm ocular. With an OIII filter, the two almost diametrically opposed segments are more distinct and connected on the E side. Three stars are involved in the N segment, which is concentrated sharply to the faintest of them at the W end. [The nebula is fairly prominent in Panstarrs g; the structure corresponds to the one seen visually.]