Thursday, 17 March 2011

SXR208: Day 6

Day 6 - CMD of clusters

 The last proper lab session tonight - and looking like the skies are clearing too. If so this could be a really good session. We have to look at clusters, two open and one globular. This was our final night and would be assessed from beginning to end.

We started by selecting 3 different choices of nebula, with a couple of backups. We hoped to get M35, M67 and M3. We then worked a plan of observing together with our darks, flats and biases we would need.

We then set about the task of getting the nights images. What cloud there was seemed to be quickly fading and things were looking good.

We took our calibration frames quickly and then searched for a reference star nearby the target to synchronise the telescope to. We had to wait for the cloud to shift, and at the same time the team in the labs were producing finding charts for the object chosen so we'd know it when we found it.

We found our first target and took several images of it, in both the V and V bands using filters for M35.
We were going to try our second open cluster, but to our horror found it was right next to the full moon. So we skipped that one for now and went on to look at the globular cluster, M3.

We got some good images of this, in both bands, and sent them off for analysis by the team in the lab.
We then had our midnight snack, and by now the moon had moved a bit, and we wondered if we might get our final target. It looked a little close, but we gave it a shot, and it worked out OK.

We were then going to try for one of our secondary targets, but the telescope went a little weird, it reset itself and decided it was now midday in 2002 so all our coordinates were off. This despite being equipped with GPS. The course director took a look at it, but decided it couldn't be fixed right now - seemed to be an issue with power sources. Anyway, we had enough data, so we all joined in on the analysis.

After gathering data from lots of selected stars, and plotting them on a graph, we were able to make a reasonable Hertzsprung Russel diagram with a part of the main sequence and the red giant turn off arm. This allowed us to estimate the age of each of the clusters, although our error bars were pretty huge.

However it was a very successful night, and with more data and more processing time we could have got a better estimate. A very positive end to the weeks observing. Back to the hotel and a quick walk on the beach at 5:30 in the morning - it was empty! The skies were a little light polluted too - so we could only see the main constellations, and the moon we'd hoped would be nestling over the water had set. So we all went to bed!

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