Art. III.—Notes on the Comet of April, May, and June, 1901..

Transactions and Proceedings of the Royal Society of New Zealand, Volume 34, 1901, Page 31

Art. III.—Notes on the Comet of April, May, and June, 1901.. By G. V. Hudson [Read before the Wellington Philosophical Society, 25th June, 1901.] Plate I. My wife and I simultaneously saw this comet from Karori on the morning of the 25th April, at 5.25 a.m. It was then rising behind the eastern ranges, and was sufficiently bright to be conspicuous as a distinct streak of light through some light cirrus cloud in the sky at the time. At about 5.40 it rose clear of the cirrus, and its brightness was so great that I was much surprised that it had not been reported as previously observed. A cablegram announcing that it had been seen in

New South Wales the same morning—though, of course, some two hours later—was, however, received during the day. Bad weather prevented further observations until Sunday morning, the 28th April, when the comet was visible for a few minutes only, owing to its close proximity to the sun. It rose about 5.53 a.m., and was overpowered by the daylight at 6.10 a.m. Unfortunately, my observatory is so situated that I could not reach it so low in the heavens, and, although I carefully swept for it between 7 and 8 a.m., I did not succeed in finding it. Judging from the view I had of the planet Mercury, I am disposed to think that the comet might have been seen with my 3¼ in. telescope at that hour, as the morning was extremely clear and bright. I next saw the comet on Tuesday, the 30th April, at 5.40 p.m. My point of observation was the main road across the Kelburne Estate. At this time the comet appeared about as bright as Mercury; the tail was indistinct, owing to the strong daylight. As it set ten minutes after I first saw it, I was unable to get home to my telescope. The next evening—Wednesday, the 1st May—I had the first satisfactory view of the comet through the telescope. The nucleus was very bright, comparatively distinct, and somewhat bean-shaped. The coma was some distance in front of it, and swept round on either side, flowing away behind the nucleus and forming two very distinct tails. There was little change on Thursday, the 2nd May. On Friday, the 3rd May, some traces of the long, faint southern tail, which afterwards became such a remarkable feature of this comet, were first seen, but not clearly until Sunday. Whilst the tails were increasing in length and brightness the nucleus declined in size, brilliancy, and distinctness. The coma appeared to be gradually swept back, until on Tuesday, the 7th, the nucleus was entirely in front of it. By this time I think the comet was beginning to decrease in brilliancy, though the disappearance of the moon during the early evening of Monday, the 6th, rendered it difficult to make any reliable comparisons with previous observations. I was, however, in the habit of noticing what stars could be seen when the comet first became visible in the evening twilight, and, from these comparative observations, I am confident that the nucleus, at any rate, considerably decreased in brilliancy before the 6th May. This, I may mention, was the first evening without the moon, and it is therefore probable that the comet would have been seen to much greater advantage had the evenings been dark during the first week of its appearance in the evening sky. The two sketches (Plate I.) which accompany these notes were made on the evening of the 6th May. One is a telescopic view of the head, and the other an attempt to show the comet as it appeared to the naked eye.

The 9th, 10th, and 11th May were cloudy, and on the 12th, when the comet was again seen, with its tail straight along the belt of Orion, a very great decrease in brilliancy had taken place. Beyond a further steady decrease I did not observe any noteworthy features during the succeeding week; but several other observers remarked to me that the space between the long, faint southern tail and the two brilliant northern tails appeared to be filled in with cometary matter of extreme tenuity. From this period to the final disappearance of the comet in my telescope on the 15th June there is nothing special to note, except, perhaps, that after about the 20th May the nucleus became slightly brighter in relation to the tail, though, of course, the entire object was continually becoming fainter. The following rough positions of the comet, taken on the dates stated, will enable amateur astronomers, who are interested, to mark out the track it followed through the constellations during the period I observed it. They were taken with an equatorial telescope of only 3¼ in. aperture, and are merely rough approximations. The right ascensions are probably correct within about one minute of time, and the declinations within ten minutes of arc. I have inserted them as they may be of some interest to other amateur observers, and it is also, perhaps, possible they may be of some little use to professional astronomers in estimating the probable orbit of the comet:— Right Ascension. Declination H m ° ′ April 25 1 22 4 0 N. May 1 3 07 0 30 S. " 2 3 22 0 45 S. " 3 3 38 0 30 S. " 4 3 50 0 20 S. " 5 4 0 0 05 S. " 6 4 14 0 10 N. " 7 4 25 0 35 N. " 8 4 38 1 0 N. " 12 5 11 2 30 N. " 13 5 20 2 55 N. " 14 5 28 3 15 N. Right Ascension. Declination. H. m. ° ' May 15 5 33 3 35 N. " 16 5 40 4 0 N. " 17 5 45 4 20 N. " 19 5 57 4 55 N. " 20 5 59 5 15 N. " 22 6 8 5 45 N. " 23 6 13 6 10 N. " 24 6 18 6 20 N. " 25 6 23 6 30 N. June 9 7 03 9 0 N. " 10 7 06 9 15 N. " 15 7 12 9 40 N.