Asterismus "Stargate"
The "Stargate" in the constellation Raven is a very well known asterism and quite popular because of its shape. It can also be found under the designation STF 1659.
Most of the individual stars just happen to be in the same direction. Only the two vertically aligned stars in the center of the asterism seem to actually form a physical
double star. Both stars are 277 and 278 light-years away from Earth, respectively.
Interestingly, the outermost stars of the asterism are also the most luminous with a luminosity corresponding to 30-50 times that of the Sun. The three stars in the center
however shine only 3-4x as bright as the sun. For the three outer stars some data shall be given: apparent magnitude, luminosity in suns and distance:
#1: 6.54mag, L= 32x L_sun, d=400.3 lightyears
#2: 6.46mag, L= 46x L_sun, d=480.5 lightyears
#3: 9.53mag, L= 52x L_sun, d=2,010 lightyears
By the way, just a few degrees east of the asterism is the famous Sombrero galaxy Messier 104.
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In a 20" telescope the asterism offers a really nice sight. The stars are quite bright and are thus clearly visible even at low magnification. Star #3 appears yellowish to
slightly orange. The surrounding area is rather star-poor.
