Sky-watching experience, observation of Comet 73/P SW3 – 22 April 2006

On the afternoon of 22nd April 2006, four of us, Akarsh, Nitesh, Hari and me went out to Hosahalli to “wach” 73P/Schwassman Wachmann.

When we left Bangalore at about 3:00 PM on 22nd, the sky was 100% cloudy, though it was fairly sunny. There was a fairly thick haze covering the sky. Ignoring this fact and going by the weather report which said “Partly Cloudy”, we went on to see some clear patches by the time we reached there (5:30 PM). By the time the sun set, we had our equipment set up and our optics aligned. (I did some animal service in the meanwhile feeding ants 😉 ). Late evening, as the sun set, we had some parts of the sky clear – especially the west – we could see a wonderful Orion Nebula. I so far not sure about the position of M43 in Orion, saw it then !!

Subsequently, the sky began to clear except for a thick haze in the south, that very soon vanished! We had very good skies indeed! By about 7:45, we had already seen M42, M43, M78, M44, Saturn, Mars, M35, M 79 and the tiny NGC 2158 near M35.

We had dinner at 8:00 and resumed observing by about 8:30 or so – picking on Whirlpool Galaxy and companion (These are interacting galaxies which share a common arm!). We could slightly make out the common arm.

The Government School headmaster, our observing ground arrived by that time with a few of his teachers and we spent till about 10:00 showing them the constellations, the planets, Beehive Cluster, Omega Centauri, M3, M81-82, the Comet 73/P Schwassmann Wachmann 3, Mizar in UMa etc.

The headmaster and teachers left us at about 10:00 and we started off with the comet. We could see BOTH BRIGHT FRAGMENTS – B & C. I have sketched them too, and they are quite ordinary sketches as I’m not experienced in drawing celestial objects.

After the comet, we went back to galaxies. We saw quite a few in Ursa Major, Canes Venatici, Coma Berenices, though very very few in Virgo. We also saw Centaurus A. Much later, when Sagittarius rose, we started working on globular clusters. Much of the clusters were beautifully resolved. I complimented Akarsh’s telescope, about its quality having really gone up after re-aluminization. We saw several globulars.

We also saw few planetaries. The moon rose by 3:30 or so, and I was awake whereas others must have all gone to sleep. The description of the two fragments of the comet 73/P-B and 73/P-C are as follows:

GENERAL DESCRIPTION : To start with, I found both the fragments of the comet under a dark-sky condition because of which details could be seen. C & B look nearly alike in both appearance and brightness. However, the biggest difference separating them is their nucleus. C has a very bright and distinct nucleus whereas B doesn’t have any. In B there was no difference between the tail and the coma and both seemed to merge into each other well. However because of the nucleus of C we could differentiate both the coma from the tail. They were strikingly similar except for the fact that B was much more diffuse. Attempted fragment “G” also because it was in the field of view, but could nowhere see it.

TAIL DESCRIPTION : Using averted vision the tails of both the comets appeared longer than with
direct vision. The tails were broader at the ends, on the side opposite to the coma region. In comet terminology, these are called “fan-tails”, I suppose. I have made a drawing of both of them when we saw it first. Both of them were close to stars. This was maybe around 11pm. Then when I remembered it around 2 am or so, I looked at it again. They had moved a lot, somewhat one-third the field of view. I have even drawn that.

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