Messier/type:M17 / emission nebula and open cluster
mag/dia/dist:6.0(cluster) / 40'x30'(nebula),25'(cluster) / 4,890 ly
constellation:Sagittarius
date/time/place:Apr21,01 / 01:45 / bangkok
trans'y/seeing/l-poll:good / fair / medium
telescope:newtonian 4.5", f 8.8
eyepieces/power:25mm / 40x
sky atlas page:22 & 15
M17: omega nebula or swan nebula. start from the lid of tea pot, star 22 'Kaus borealis' hop to stars 21 & 13,then hop to star mag5 & 6 near M25 (change to sky atlas p.15) ,further hop to a star mag5 close to M17. shift the expected location of M17 to the center of FOV of finder scope, goto eyepiece, M17 appeared as big open cluster with faint nebulosity ,the major part of nebula that I saw is the body of the Swan, I couldn't see the neck which is form like '2'(I only seen '_'). however, it was very impressive with visual observing. Home
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