Observing Log for 2005-10-09
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2005-10-09


Location: Billingborough (South Lincolnshire, UK)
From: 2005-10-09 20:26 UT
To: 2005-10-09 22:40 UT
Equipment: Sky-Watcher Explorer 130M
Temperature: 8.8C
Humidity: 78%
Notes:

Reasonably clear night with some mist hanging around — mostly noticeable as I looked towards the horizon. The sky wasn't as dark as it can be but I could still clearly see the Milky Way.

The main aim for this session was to have a look at Mars. At the start of the session it had already cleared the roofs to the East of me and it was almost clear of the worst of the murk and mist.

I set the telescope up and opened it for cooling at the very start of the session and then spent some time preparing and letting my eyes dark adapt a little.

Mars

From: 2005-10-09 20:46 UT
To: 2005-10-09 22:05 UT

First located Mars with the 25mm eyepiece. Even with such a low power (x36 on the 130M) I could easily tell that I was looking at a disk that seemed to be displaying a bit of a phase. The image was bright and displayed spikes corresponding to the arms of the spider that hold the secondary mirror in the 'scope. The image seemed very steady.

Switched to the 6mm eyepiece. The image looked huge and rather unsteady. Quite a bit of false colour was visible around the edge of the planet. The image didn't look very crisp and was rather unsteady. Without any sort of filter in place the surface still seemed very bright and rather washed out. However, there did seem to be an obvious variation in the colour of the disk hinting at some sort of surface feature.

At first glance the feature had the appearance of a short, thick line across the face of the planet.

Added the #21 Orange filter to the 6mm eyepiece. The image now seemed a lot sharper and the false colour was gone. However, there did appear to be an occasional fringe to the edge of the planet. The "line" that I mention above now seemed a bit more obvious and, with the Orange filter, seemed to take on a more "arrowhead" appearance.

The sight of the marking seemed to come and go and was rather fleeting. One moment it seemed very obvious to the eye and then the next it was rather indistinct. While the shape didn't appear to change as the view came and went I noted that it would have been very difficult to sketch.

Next, I combined the #21 Orange filter with the #15 Yellow/Orange filter but I was unable to detect any difference in the image.

After that I tried the #56 Green filter with the 6mm eyepiece. No real detail of any sort was obvious with this combination. I'd have said that the image seemed about the same as with the unfiltered 6mm eyepiece — only greener.

Around this time (21:25 UT) the house below where Mars was positioned lit a fire and there was a fair bit of smoke coming from the chimney. None of the smoke appeared to be getting in the way of my view of the planet but I imagine that the warm air that was rising from the fire interfered with subsequent views.

Now switched to the 6mm with just the ND13 filter to see what effect it would have. The view didn't seem any different from the view without a filter expect that it was dimmer (which was pretty much what I expected to see).

Despite not being able to tease any extra obvious detail out of the image the thing that was most impressing me by this time was the difference in the size of the image of Mars when compared to the first time I looked at it in the 130M. Even though I knew this was going to happen (that the apparent diameter would increase over time) the difference was still quite striking.

Next I tried with the 6mm and the #11 Yellow/Green filter. For a few brief moments, when the image seemed very steady, I was sure I could see slightly more detail than I had earlier. This was, however, a very brief view. I wasn't sure if this was down to the choice of filter, a lucky moment of very steady seeing or simply that Mars was now higher in the sky than when I'd started the observation session. Could simply have been a combination of all of the above.

Finally I decided to try with the 10mm eyepiece and the 2x barlow plus the #21 Orange filter. This seemed to be a good combination. Now I could see what appeared to be two darker areas on the surface. One seemed to be a vaguely rounded but linear feature (sort of an elongated oval) and the other appeared circular and smaller. The contrast wasn't great and, as with other filter and eyepiece combinations, the view seemed to come and go but there was no doubt that I was seeing slightly more than I was before.

What was most surprising about this combination was that, in the past, I've had focus trouble with the barlow and had more or less given up on using it. However, this time, the image seemed to come to a pretty crisp focus.

Double Cluster

From: 2005-10-09 22:11 UT
To: 2005-10-09 22:20 UT

Given that it was now very well positioned for me to view with the 'scope I pointed the 130M at the Double Cluster (AKA Caldwell 14 or NGC 869 and NGC 884) in Perseus. At first glance it looked like a rather sparse grouping of stars with two obvious areas of concentration. However, as my eyes adjusted both areas of concentration seemed to become richer and richer. I noted that both of the main concentrations fitted in the field of view of the 25mm eyepiece.

M1

From: 2005-10-09 22:26 UT
To: 2005-10-09 22:40 UT
Temperature: 7.9C
Humidity: 79%

Although it was still very low, just above the houses to the East of me and still in the thin mist, I couldn't resist trying to have a look for M1 (AKA The Crab Nebula or NGC 1952) in Taurus.

Using the 25mm eyepiece on the 130M I found it with little trouble. It was rather hard to make out (most probably due to the conditions under which I was trying to observe it). It had no real obvious shape to it, all I could see was an indistinct but visible "ghostly presence". Given that it was (just) visible in such bad conditions I image that it will make for a good target when it is higher in the sky.

By 22:40 UT I was starting to feel the cold and was also starting to feel tired so decided to call an end to the session.


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Dave Pearson <davep@davep.org>
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