Harold Corwin

IC 1990 is part of the reflection nebulosity around the Pleiades. It was first noted by Stratonoff (AN 3366 = AN 141, 103, 1896) who found it on a plate exposed for 25 hours over nine nights. He describes it as a "straight wire between RA 03 40.7 and Dec +24° 04', and RA 03 41.9 with the same declination" (1896.0 positions precess to 03 46 53, +24 23.5 and 03 48 06, +24 23.3 for J2000.0). "Its width is about 20-30 [arcsec]." He adds that "The nebula is nearly parallel to the known nebula discovered by M. M. Henry, having the same form and found a little to the south."

This is a pretty good description of the area just north of Alcyone, though we now know of many other filaments and patches of nebulosity here. Stratonoff's declination is a little too far north (by about three arcminutes), and coincidentally, Dreyer applied the precession in declination with the wrong sign, so the NPD in the IC is incorrect -- that number should be "66 03", not "65 49".

The position I've adopted is more or less the center of Stratonoff's streak.

― IC Notes by Harold Corwin

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