4.7" Sky-Watcher

Obs. place: Kasiniemi, Padasjoki, Finland
Date: 16./17.9.2009
Bortle class: Class 2 (typical truly dark site)
SQM-L reading: 21.33
NE Lim.mag: 7.4m (zenith)
Background sky: 2
Seeing: 2
Transparency: 1-2
Weather: +8.0°C, humidity ~70%, faint breeze from the SE.

Observing time 2h 53 minutes (0.27 am ->). G 1 cropped - fairly easily visible from Sipoo. Translated from voice recorder. Edits are marked with a pair of ( )


G 73 with 4.7" Sky-Watcher @ 240x

 Started with Andromeda Galaxy high (~64°) in the sky, little past midnight. The position of the first globular cluster, G 73, was not difficult to find – it is just SW from a 9th magnitude star (PPM 43193). Using a printed DSS map of the region, I quickly found the 12th magnitude star (GSC 2805-0819) leading to the globular cluster. From this star, less than 2’ to the NE, is the globular cluster G 73. It appears as a stellar object, slightly fainter than the two stars to the E. Averted vision is needed to see this cluster and it cannot be held steady for more than 30% of the time. Looking at the object, there is no indication that this is nothing more but a typical, faint star in the field.

G 78 & G 72 with 4.7" Sky-Watcher @ 240x


Moving forward and to the south. Takes a little time to find the correct position. Field confirmed – two 12th magnitude stars near and W from the cluster (see the sketch). There are only three stars that fit the bill. Two fairly faint, nearly 15th magnitude stars are directly E from the brighter 12th magnitude (reference) star. There is a brighter, maybe 14th magnitude star directly E from the fainter 12th magnitude (reference) star. This appears to be the globular cluster G 78. As with the previous cluster G 73, this is nothing more but a stellar object. The magnitude of the globular is somewhere below 14.5 magnitude - brighter than the two faint stars to the S.

Another globular cluster – brighter than 15th magnitude - more to the north but still probably in the same field field of view. Moving N from the two 12th magnitude (reference) stars to three 14th magnitude stars. NE from here is yet another 12th magnitude star. The globular cluster, G72, lies between the three stars and the bright one. With the correct position in hand, it was not too difficult to get a few glimpses of this, probably fainter than 15th magnitude, stellar point in the connect position. The identification is quite certain since there are not many stars in the region. G 83 not seen (might have fitted the field of view too but MegaStar had no listed magnitude for it so I decided to let it go).

G 76 with 4.7" Sky-Watcher @ 229x


15 minute break. The sky looks good – humidity was on the rise but the summer Milky Way was beautifully visible from horizon to horizon with a huge amount of detail to the naked eye. Looking to Pegasus, M15 was plainly visible with the naked eye even by using just direct vision.

Next in line was G 76. I started the search by locating M32 with the 25mm Omni eyepiece. SW from the galaxy is a bright, 7th magnitude star. More to the west is the H II region NGC 206 and between these two should a triangle of 11th and 12th magnitude stars and the globular cluster. Locating the small triangle was easy at low power. Cranked up the magnification and used 6.3mm Plössl to give me 229x. MegaStar confirms position is correct but the software does not show G 76! Marked DSS image shows it. Also MegaStar shows only the triangle of stars in this region. Still, with a little effort I managed to spot three very faint stellar objects in near the three stars - moving past the GSC catalog. Some of these had to be G 76. Sketched the field carefully - study later. MegaStar also shows several globular clusters in the region when the magnitude limit was removed. G 85 (labeled G 80 and position marked with "x") was tried but in vain.

G 280 & G 272 with 4.7" Sky-Watcher @ 192x


Moving forward - going after G 272. It took only a couple of minutes to find the field and get myself properly orientated with it. 9th magnitude star (PPM 43268) helped quite a lot.

G 289: It didn’t take more than a few seconds to realize this object was not a globular cluster. Appearing as a 12th magnitude star just above the 9th magnitude “guide star” it is too bright to be a real globular cluster – G 1 has a magnitude of 13.8 and it is the brightest GC in the AG (Andromeda Galaxy).
G 285: See previous. Bright, slightly brighter than G 289, 12th magnitude star. Not an extragalactic object?
G 280: This looked more promising as it was invisible with low magnification. Using 240x, barely detected two very faint stars in the correct position. Without a DSS photo, it is a fool’s game to try to guess which one is the GC. The star to the W appears slightly brighter, being about 14.5 magnitude. Check later.
G 272. As with above and I could get only a few glimpses of it using averted vision. The position seems correct. 11th magnitude star to the NW. Stellar. Very close to 15th magnitude.