Post by virgo on Oct 6, 2008 12:45:04 GMT
Hello,
The sky last night ( 5th October ) was cloudy since dusk, but at around 21hrs the cloud began to break up and at 22hrs the sky was cloud free.Seeing this I dragged out my 250mm dob to do some deep sky observing, but on looking around the sky I noticed that it was different. The stars were not twinkling! Capella in the northeast shone with a steady white lustre, while Vega in the northwest showed a similar appearance. Normally the stars show varying degrees of scintillation, depending how disturbed the atmosphere is.Having set the dob up outside I examined the star fields around Deneb, in the constellation of Cygnus and noticed that they appeared unusually sharp and well defined.Changing to a 7 mmNagler eyepiece ( X 180 ) I centred Deneb in the field, and at once noticed that the Airy disc was almost motionless with just the occasional ripple. I then directed the dob towards Auriga, which by now was well up in the eastern sky and zeroed in on Theta Aurigae which is a close unequal double and always a fair test of telescope defining power as well as a test of sky quality.
The pair showed up reasonably well at X180, but with a good quality X2 barlow they were displayed beautifully with just occasional ripples. I then moved on to M1 which was nearby and it too appeared unusually well defined.
While taking a break from observing, I noticed another unusual thing about the sky, I could actually see the Milky Way, that band of faint light running from Auriga through Cassiopea to Aquila in the west. From my site this is a rare event to say the least.As expected this idyllic state of affairs did not last, and around00.30 hours the first wisps of cloud heralded the inevitable rain which duly arrived next day.
The above proves that ideal sky conditions do sometimes happen, and the amateur observer should be quick to take advantage of this.
Regards,
John.
The sky last night ( 5th October ) was cloudy since dusk, but at around 21hrs the cloud began to break up and at 22hrs the sky was cloud free.Seeing this I dragged out my 250mm dob to do some deep sky observing, but on looking around the sky I noticed that it was different. The stars were not twinkling! Capella in the northeast shone with a steady white lustre, while Vega in the northwest showed a similar appearance. Normally the stars show varying degrees of scintillation, depending how disturbed the atmosphere is.Having set the dob up outside I examined the star fields around Deneb, in the constellation of Cygnus and noticed that they appeared unusually sharp and well defined.Changing to a 7 mmNagler eyepiece ( X 180 ) I centred Deneb in the field, and at once noticed that the Airy disc was almost motionless with just the occasional ripple. I then directed the dob towards Auriga, which by now was well up in the eastern sky and zeroed in on Theta Aurigae which is a close unequal double and always a fair test of telescope defining power as well as a test of sky quality.
The pair showed up reasonably well at X180, but with a good quality X2 barlow they were displayed beautifully with just occasional ripples. I then moved on to M1 which was nearby and it too appeared unusually well defined.
While taking a break from observing, I noticed another unusual thing about the sky, I could actually see the Milky Way, that band of faint light running from Auriga through Cassiopea to Aquila in the west. From my site this is a rare event to say the least.As expected this idyllic state of affairs did not last, and around00.30 hours the first wisps of cloud heralded the inevitable rain which duly arrived next day.
The above proves that ideal sky conditions do sometimes happen, and the amateur observer should be quick to take advantage of this.
Regards,
John.
