| Object/type: | M 51 / Whirlpool Galaxy |
| mag/dia/dist: | 8.4,SB:13.1 / 11.2' X 6.9' / 15,000,000 ly |
| constellation: | Canes Venatici |
| date/time/place: | Dec 22, 01 / 05:20 / bangkok |
| trans'y/seeing/l-poll: | goog / good / medium |
| telescope: | newtonian 4.5" f8.8 |
| eyepieces/power: | 25mm / 40x |
| sky atlas page: | 7 |
Observing details:Start star hopping from Alkaid in Ursa Major, hop to star 24, adjust to get star 24 and star BSC5067 in the same FOV of finder scope (about 5 degree), looking for three stars magnitude 7.0 at half way between star 24 & BSC5067. At eyepiece, center the three stars on FOV (about 1 degree), they formed as a right triangle. M51 locates at the top corner of another triangle on the same base line but opposite to right angle. See below FOV chart. M51 appeared as round, large, very faint, unstable, quite harder than M95 according to low altitude, M51 locates in highly sky glow area of Bangkok. It seems to have some small stars near its center. Jiggle technic (slightly knocking at eyepiece) slightly improve image blink-up. At 05:40, totally disappeared.
Refer to text: The first galaxy in which spiral structure was observed, by Lord Rosse in 1845. Several of the spiral arms can be traced visually with a 10 or 12 inches reflector under good conditions. The distance give by sky atlas companion is 37,000,000 ly, hubble class Sc, physically connected to small neighboring galaxy, NGC 5195. A 12th-mag. foreground star, lying near M51 nucleus, is often mistaken for a supernova.
