19, April

I’m beginning to see a trend in my observational posts recently. It runs along of the lines of  ‘Observed this, but conditions were poor’  Last weekend was no exception, but at least I got two nights in a row to not really see very much. I won’t bother to give any detailed observing stats,  as conditions were so poor, but I was just so desperate to get out and see something- anything!!

The evening of the 19th started with my local astronomy club meeting and a super talk on Star formation by our local PhD student  Darryl Sergison who is currently based at Exeter University. Conditions that evening were excellent and we rushed back home to open up and finally got to see Comet C/2011 L4 through the big scope for the first time. Up until now, she’s been lurking in the gloom to the North – a part of the sky that is obscured by the observatory roof and the house. But tonight, she had just cleared both.

Sadly, by the time it got dark enough, those clear skies turned for the worse when a low bank of fog rolled in. My log for the session reads

 ‘Awful. Observing in fog is not to be recommended. Dew forming on scope within about 10 minutes.’  

Before it got too bad I got a glimpse of the Comet through the 18mm SWA but saw little more than I had seen through a pair of 10×50 when conditions at the BAA weekend were better. I was hoping to see the difference  of the hard and softer edge sides of the tail that are so obvious in photographs that I have seen. Sadly,  what should have been  the harder edge didn’t look any different from the other as conditinons rapidly deteriorated..

The only other objects bright enough to shine through the murk, were Saturn – which I’m glad has now made an appearance – and the Moon. With conditions getting worse by the minute, Saturn was attempted first.

 ‘Cassini seen and the shadow of the inner ring on the planets surface.  North equatorial belt observed. No other detail seen on surface. Tilt of rings allow Southern part of planet to protrude below the Rings’

 Before it all turned to crap, I slewed to the Moon to see if it was possible to see the Rille running down the floor in the Vallis Alpes

Shadows formed by the Eastern wall made me think I could see the Rille, but on reflection I think conditions were such that this confused the eye and the Rille was not observed.

All this was squeezed in a 45 minute session.

20, April

The following day went much the same way.

Sod’s law in operation today. It was clear blue skies all day up until the point at which I decided to open up, when small batches of low cumulus cloud started to form. The observatory is acting as a cloud magnet again.

sunspot 1726 20-04-2013

However, I’m still amazed at how much detail can be seen on the Sun’s surface despite quite thick cloud cover.

One thing I did notice whilst observing Sunspot 1726, is that the contrast increases between light and dark areas, when you observe through cloud. It seemed that I was able to see detail more clearly than would have been otherwise. To see if this was just my imagination playing tricks, I attached a 0.9ND filter to the eyepiece and made the observation again. During clear spells – although these were very short spells – I did note this increase in contrast. It was difficult to say if this increased the ability to see more subtle detail than without the filter, but I would like to try this test again to see if there is anything in it.

Later that evening, there were enough gaps between the Cumulus, but still a lot of high thin stuff around, but I went for it again and opened up.

I won’t even mention the two observations of the Globular clusters M53  and M3 which literally were fuzzy blobs with no discernible structure.

M40 on the other hand, made me think that the mount’s pointing had gone tits up. All I could see in the field of view were two stars at the centre of the FOV and a bright 5.5mag at the edge. Looking at Astroplanner confirmed that ‘Yes’, the scope was pointing at M40, but surely a Messier Object cannot be just two stars. I started to smell a rat when I looked at the objects name which was Winneke 4 and a type listed as Dbl+Asterism.

M40

While there are 33 Open Cluster objects in Messier’s list, M40 is the only one that only contains two stars, so you really do wonder why it ever got added. O’Meara’s ‘The Messier Objects’ starts the description of M40

There is nothing astronomically significant about M40, except that it is a historical curiosity

Reading further you begin to understand the reason why Messier observed it, but not really why he added it to his list! Apparently in 1660 John Helvelius  reported seeing ‘a nebula above the back’ of Ursa Major. At the time, the quality of  Helvelius’s scope was such that a close double could well have appeared to have had nebulous properties, but in October of 1764 when Messier made his observation at the reported position, with a much more sophisticated scope, only found the double star and was not fooled by it. Nonetheless he still added it to his list.

At the time of my observation I did get a sense that the brighter star of the two ( Winneke 4) was redder than its fainter companion, but apart from that I think I can say that M40 is the  least interesting of the Messier Objects that I have observed so far.

As an aside, had the transparency been a lot better  a much more interesting 12.0 mag Galaxy,  10 arc seconds to the West, would have been a more challenging and satisfying observation.