Observing Log for 2007-04-27
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2007-04-27


Location: Billingborough (South Lincolnshire, UK)
From: 2007-04-27 13:15 UT
To: 2007-04-27 13:25 UT
Equipment: Solarscope
Canon EOS 400D
Temperature: 15.1C ...
Dew Point: 9.7C ...
Humidity: 70% ...
Wind Speed: 0.6mph ...
Wind Dir: East ...
Pressure: 1023.4hPa ...
Notes:

Mostly cloudy all morning but started to clear into the afternoon. Although it was still a little hazy I took the Solarscope out to do a quick sunspot count.

Sun

From: 2007-04-27 13:15 UT
To: 2007-04-27 13:25 UT

New active area 953 visible with a single and reasonably large spot (this is the first sunspot I've seen since 2007-03-03). The umbra appeared quite dark and a large penumbra was visible too.

Given how large the spot was I decided to try and take a photograph with my Canon EOS 400D:

Active Area 953

Location: Woodland Waters (South Lincolnshire, UK)
From: 2007-04-27 19:55 UT
To: 2007-04-27 22:48 UT
Equipment: Antares 905
Notes:

A clear night had been forecast so John Turner and myself met up at Woodland Waters for a joint observing session. I took my Antares 905.

When we arrived the sky was mostly overcast with a lot of cirrus. It started to look like we'd abandon the session. However, it started to thin out a little so we decided to stick with it and see how it went on — it did look like it would be a shorter session though.

Venus

From: 2007-04-27 19:55 UT
To: 2007-04-27 20:15 UT

Started out with a view of Venus, even though the sky was still quite light. Using the 905 and the 6mm eyepiece the view wasn't too bad. There was some false colour and some unsteadiness at times but it was easy enough to make out the planet's phase (which had obviously changed since the last time I observed it).

I then added the contrast booster and, as I've found before, the image improved some more.

Giving a Tour of the Sky

From: 2007-04-27 20:16 UT
To: 2007-04-27 20:54 UT

Around 20:16 UT we were approached by two blokes who were part of a group of people camping in the field. They asked what was happening (apparently assuming that we were watching an "event" in the sky) and, after telling them that we were simply observing what was available, we asked if they'd like a look through the 'scopes. They said they'd love to.

Neither of them had looked thought a telescope before so between us John and I showed them Venus, Saturn and various views of the Moon. Both were impressed and, as normally happens, Saturn was the real winner with the most "wow" factor.

We also had a good chat about various things astronomical and how we'd got into observing in the first place. I also spent some time trying to explain to them what they'd been seeing when viewing Venus (the significance of Venus' phase wasn't clear to either of them and it took a little explaining).

Since getting into observing this was the first chance I've had to do this sort of thing. While it wasn't exactly sidewalk astronomy it was nice to give people a view though my 'scope and to answer some of their questions.

The Moon

From: 2007-04-27 21:35 UT
To: 2007-04-27 22:48 UT

After our two guests headed back off to their tent I had a sit down and a coffee break. By 21:35 UT it was obvious that the sky wasn't going to improve at all. There was still a fair bit of haze around and the Moon had a pretty impressive halo around it. There was no chance of any deep sky observing.

Trying to make the most of the evening I decided to do some observing of the Moon. With the 6mm eyepiece in the 905 I had a quick scan along the terminator and could see that the view appeared somewhat flat and muted.

Around 21:50 UT I concentrated on a large highlighted "wall" some distance into the Moon's shadow. Using my Moon map I quickly figured out that what I was seeing was the eastern wall of Gassendi.

I spent some more time just wandering up and down the terminator and then, at around 22:19 UT, I noticed a very strange thing right in the terminator near Delisle. What I was seeing was a perfect triangle, bright corners and obvious sides. It looked very artificial. Realising that I must be seeing some sort of optical effect I had a look at my map to try and figure out what I was really looking at.

To the west of Delisle are some mountains (unnamed on my map) which appears (according to my map) to have three peaks in a rough triangular formation. Given that the terminator was running right through these three peaks it would seem that my brain was "filling in the blanks" and joining the dots to make a triangle with actual sides. Even though I now knew what I was looking at I couldn't stop seeing what I'd initially seen.

I got John to also have a look too and he confirmed the effect.

Also, close to Delisle, I could see Mons Delisle as an inverted Y.

By 22:26 UT the sky was getting somewhat worse although the halo around the Moon was becoming more impressive. For a short while it had quite a lot of colour to it. It appeared yellowish in the inside (the part touching the Moon) and appeared to get redder out towards the edge.

Because of the deteriorating conditions I had another short break to see if things might improve again. However, they didn't and at 22:48 UT John and I decided to call it a night.


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Dave Pearson <davep@davep.org>
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