| Type | Star |
|---|---|
| Magnitude | 6.95 | Right Ascension | 6h 32' 17.8" (2000) |
| Declination | 17° 46' 47" N |
| Constellation | Gemini |
| Classification | F5IV |
Andrew Cooper
Nov 23, 2023 Waikoloa, HI (map)
20cm f/6 Newtonian, Cave Astrola @ 76x
Seeing: 6 Transparency: 6 Moon: 0%
20 Gem and 21 Gem are a fine pair of 6th magnitude stars separated by 20", 21 Gem is the northeastern component, a pale yellow contrasting nicely with the white 20 Gem to the southwest, both are set in a field rich with stars close to the galactic plane
There is some discrepancy with the identity of 21 Gem as Flamsteed appears to have made a 1' RA error in the coordinates, many sources including Wagman and SIMBAD list 21 Gem as non-existent which seems less likely than a simple digit error in hand-transcribed lists
Gaia EDR3 data shows 20 Gem and 21 Gem share closely matching parallax and proper motion
| 19 Geminorum | 20 Geminorum | 22 Geminorum |
| 23 Geminorum | AB Geminorum | Alhena |
| Bochum1 | CR Geminorum | Jonckheere 900 |
| NGC 2218 | NGC 2234 | PK194+2.1 |
Drawings, descriptions, and CCD photos are copyright Andrew Cooper unless otherwise noted, no usage without permission.
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