Gemini - The Twins
Pronounced "Jem - in - Eye"
Where to find the constellation
Constellation Chart
Gemini is another constellation where the majority of DSOs available to the beginner are open clusters. Quite a large 'zodiac' constellation, representing the mythological twin brothers, Castor and Pollux.
Brothers to Helen of Troy - apparantly the ancient Greek words 'kastor'
and 'Polludeukeis' mean literally 'beaver' and 'very sweet'
The star Castor is a tight double, a good test of amateur optics - Gemini also contains ngc2392, the 'Eskimo Nebula' a beautiful planetary neb - and M35, a fairly large populous open cluster, as well as many other open clusters of various sizes.
Nicely positioned high to the East during Winter and Spring - sweeping overhead, and eventually West, as the night progresses.
M35
The only Messier object in Gemini, quite a rich open cluster, with two smaller open clusters nestled close-by (ngc2158 and Collinder 80)
Collinder 89
Quite large, but very sparsely populated open cluster - often overlooked due to it's proximity to the more well-known M35
Eskimo nebula - ngc2392
Beautiful planetary nebula, small, but fairly bright, and easy to find.
However, through an amateur scope, you won't see the colours, this is a more realistic view as seen through the eyepiece.
(I've added Saturn in there for a size comparison)
Castor
A multiple star system - 3 components are visible at the eyepiece (although there are more)
A and B components are a very tight double, only 3 arcseconds apart - a good test of the optics in a small scope is to 'split' these - you need to see black 'space' between the two components to have successfully split the double.
There's also a third, dim component, just over an arcminute away.
Gemini NGCs (with magnitudes) - from my own "1200 Northern NGCs" list
For those with 'GoTo' or a good chart.
2129 - OC - 6.7
2158 - OC - 8.6
2168 - OC - 5.1 (m35)
2331 - OC - 8.5
2339 - Gal - 11.7
2371 - PN - 13 - 2371 and 2372 are seperate parts
2372 - PN - 13 - of the same dim planetary nebula
2392 - PN - 8.6 (Eskimo nebula - surface brightness 6.7)
2395 - OC - 8
2420 - OC - 8.3