…and the clear nights keep coming. The Moon is back but these small cluster observations aren’t particularly affected by its presence.
Date: 1/10/2015 Time: 19:54 – 00:29 UT
Seeing: II Mostly Stable, Transparency: II Clear, Temp:10.5c, Pressure: 1013mb, Humidity: 81%, Dew Point: 8.0 , Wind: 8.0mph, SQM: 17.8 NELM: 4.9
Collinder 420, NGC6910
In the Altair 250mm f/8 RC, 14mm Delos, 145 X, 29.8′ West is to the 7 O’Clock
At the centre of the cluster are two bright stars of 7.2 and 7.4 mag running Eastish/Westish. These form the two heads of a ‘Y’ shape with fainter stars forming the rest of the asterisum. This tight shape is contained within a 3.5 arc/min circle.
Within the 10 arc/min circle on the chart, there are about 18 fainter stars ranging from 10.0 to 11.8 mag. There are unresolvable fainter stars and these remain unresolved in the 10mm Delos at x203.
There is a line of stars that head from the cluster centre to the edge of the FOV towards the West.
Collinder 419, Lund 940, OCL 177
In the Altair 250mm f/8 RC, 10mm Delos, 203 X, 21.3′ West is to the 7 ‘Clock
To the North of the centre of the cluster there is a bright Blue double of 8.0 mag. Within a 5 arc/min circle there are about 10 stars ranging from 8.0 to 13.7 mag, which is a big improvement in numbers from the last observation 4 days earlier. The odd thing is that the Seagull asterism is hardly prominent this time round.
Collinder 431, NGC7039
In the Altair 250mm f/8 RC, 40mm Plossl, 51 X, 52′ I didn’t record where West was.
What looks to be the cluster occupies about 25 arc/min in diameter. However the marked boundary for NGC7039 is 15 arc/min and on which there are two bright 8.8 and 6.7 mag stars to the SW and NE respectively.
Switching to the Altair 250mm f/8 RC, 14mm Delos, 145 X, 29.8′ I count about 15 stars within this 15 arc/min circle. To the SE are a grouping of stars of various magnitudes that you would think were part of the cluster being observed – but they are not.
The cluster appears to be in two sections. Around the bright blue 8.8 star to the SW , there are three bright stars ranging from 10.0 to 11.7 mag and surrounding those a concentrated number of fainter stars ranging from 12.1 to 13.9 mag – again I didn’t count these.
Around the 6.7 mag star to the NE, there are a number of fainter stars in the 12.8 to 13.7 range – sorry didn’t count them !
Collinder 434, NGC7062
In the Altair 250mm f/8 RC, 40mm Plossl, 51 X, 52′ West is to the 7 O’Clock
The most striking first impression is of a North pointing arrow of about eight 8.0 to 10.0 mag stars. This arrow is offset to the North slightly and in the centre of the FOV is a very small tight cluster of about 4 stars ranging from 10.0 to 12.5 mag which form a square, which in turn are surrounded and a fuzz of unresolvable fainter stars.
Switching to the Altair 250mm f/8 RC, 10mm Delos, 203 X, 21.3′ , that fuzz of faint stars are now resolved into 15 to 20 faint stars ranging from 11.7 to 13.1 mag and form an tight oval orientated E/W
Collinder 436, NGC7067
In the Altair 250mm f/8 RC, 10mm Delos, 203 X, 21.3′ – I didn’t record where West was.
Of the brighter stars, there are about 6 stars ranging from 9.4 to 11.7 mag and in among these are about 8 to 10 resolved stars in the 13.8 to 14.4 mag range. There are more stars there, but these are unresolved.
Compared with the observation the night before- this was fairly rubbish