Observing Log for 2005-09-13

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Location: Billingborough (South Lincolnshire, UK)
From: 2005-09-13 10:20 UT
To: 2005-09-13 10:31 UT
Equipment: Solarscope
Naked Eye

Another look at sunspot 798 with the naked eye and with the Solarscope. Sky wasn't too bad again today — just a little hazy.

Sunspot 798

From: 2005-09-13 10:20 UT
To: 2005-09-13 10:31 UT

First looked for sunspot 798 with naked eye and eclipse shades. It was very easy to see as a rather large dark spot.

In the Solarscope it was obvious that the shape of the spot had changed a lot from yesterday. Although the following sketch gives the impression that it's smaller than yesterday it actually seemed to cover slightly more area than I remember from the previous observation.

Made the following sketch:

Sketch of Sunspot 798

Location: Billingborough (South Lincolnshire, UK)
From: 2005-09-13 21:55 UT
To: 2005-09-13 23:00 UT
Equipment: Sky-Watcher Explorer 130M

Given that the sky was reasonably clear and that the forecast for the next few days didn't look too good I decided to have a quick session looking at Mars.

Conditions were slightly warm and breezy with the Moon just past 1st .


From: 2005-09-13 21:55 UT
To: 2005-09-13 22:49 UT

Mars was still quite low. There was also a hint of haze in the air which seemed to dim it slightly. After first locating the planet with the 25mm eyepiece I switched to the 10mm eyepiece. The image was quite washed out and was dancing around quite a bit. Initially about all I could make out was that there was a visible phase.

The breeze calmed down for a moment so I switched to the 10mm with 2x Barlow. As normal I struggled to get useful focus with the Barlow and also noticed that there was some significant false colour around the image of Mars.

Switched to the 6mm (with no Barlow) and the image was much crisper. Mars appeared very bright, even to the point that I was getting four very obvious spikes off it. In steady moments there was a hint of surface markings visible. As with a few nights ago, these appeared as vague differences in colour.

Added the #21 Orange filter to the 6mm eyepiece. This reduced the glare of the image, the surface looking less washed-out. The hint of markings seemed to improve although they didn't improve to the point that I'd have been able to draw a reliable sketch. They were there, visible but also somewhat indistinct. The fact that the image wasn't terribly steady most of the time adding to the problems.

Next gave the #80A Medium Blue filter a go with the 6mm eyepiece. I don't know why but I was initially surprised to see that this made Mars look white, not blue. The markings mentioned above were still visible and, this time, appeared as darker gray areas.

Decided to experiment a little more by combining the #21 and #80A filters. The image looked more or less the same as it does with the #21 filter on its own although I'd be tempted to say that the darker areas appeared a little easier to notice — although still somewhat indistinct.

Also tried the #56 Green filter with the 6mm eyepiece. Other than making Mars look somewhat green this didn't seem to make an awful lot of difference to the image.


From: 2005-09-13 22:57 UT
To: 2005-09-13 23:00 UT

Because it was close to Mars and is also an easy target I decided to have a quick look at M45 — The Pleiades. Had a look with the 25mm eyepiece. Quite a stunning sight through the 'scope. The main pattern of stars more or less filled the field of view.

By around 23:00 UT the breeze was picking up quite a bit and the sky was becoming more washed-out due to the Moon so decided to call an end to the session.

Page last modified: 2013-04-09 09:19:19 UT
Dave Pearson <davep@davep.org>
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