Hyakutake Two

Photo of Comet Hyakutake by Steve Renshaw (March 26, 1996)

How Hyakutake Found Comet 1996 B1

By Masaki Okamoto

March, 1996

Now Comet Hyakutake is very popular. I still haven't seen it because of poor weather peculiar to this time of the year in this area. But I have another way to enjoy the comet. I can read what Yuji Hyakutake wrote himself about his discovery. To share my pleasure with others I have translated his report published in the April issue of Gekkan Tenmon (Monthly Astronomy), one of the popular amateur astronomical magazines in Japan.

I searched for a comet for only 4 hours in two nights in January. We had a long spell of disagreeable weather here since my discovery of 1995Y1 a month ago. On January 30, as it was likely to clear up at dawn, I left home for my observation place. I wanted to get there at 3:30 AM when the Moon would set in the west. The sky was in a nice condition when I left home, but I found low clouds flowing from the west at the observation place. The zenith of the sky began to clear around 4:00 AM. I tried to turn my binocs to see Comet 1995Y1. When the binocs were pointing almost straight up, I managed to catch three objects together: M101, NGC5474, and 1995Y1 a little smaller than M101. My comet was about 9th magnitude, 8' in diameter. As I made a sketch sitting in a awkward position, I got a pain in my neck. After sketching I began comet searching freely as usual.

It was about 20 minutes later when I unexpectedly came across an object like a comet. At first I didn't know where it was because of the clouds. Judging from the constellations that were sometimes glimpsed between floating clouds, the object seemed to be in the southeast of the Crow Constellation. I had moved my binocs to the southern part of the sky without being aware of it. I was surprised when I mentally connected the stars. Unbelievable! I had thought I already knew the pattern of these stars well! I was very familiar with the star map of this area because I had often confirmed 1995Y1 there! I had completely memorized the arrangement of stars around there. The memory was still fresh to me... Too new to forget! I said to myself "I must be dreaming".

I left my binoculars for a while to calm myself down, and then I started drawing the comet-like object. It was much more condensed than 1995Y1. It was still dark but easy to see... 11th magnitude, 2.5' in diameter. It was at 4:50 AM when I looked at my watch after marking its position. What I had to confirm first was whether it was moving or not. At 5:40 AM, the morning twilight began. I again went back to the binoculars. I couldn't confirm the motion of the object by comparing it with the stars around it. I finally gave up trying to confirm. I concluded to myself that the "possible comet" should be coming directly toward the Earth. I quit searching when I heard the siren for 6:00 AM at the foot of the hill.

I came back home and checked comets which had already been discovered, but I couldn't find reports referring to the comet-like object in question. So I began to draw up a report. I copied the position of the morning's comet-like object on page 332 of Uranometria 2000 from the previous sketch. I had already marked the position of 1995Y1 on the star atlas. I was stunned by the curious coincidence. The new object was in a very similar location to where 1995Y1 was found... A few minutes different in R.A and 3 degrees to the east in Dec. I sent the report to the New Astronomical Findings Information Department at the National Observatory. I also sent a fax to Syuichi Nakano (the Calculation Center of O.A.A) and also left a message on his answering machine.

At midnight the condition of the sky was poorer than the previous night, and what was worse, a drizzle began to fall at 0:00 AM. Just as I had decided to give up trying to confirm the object that morning, a fax came to me saying that my find was confirmed. The fax was sent from Ikari in Otu to Nakano at 2:58 AM. It was sent to me from Nakano again at 3:03AM. I was so glad to be given such a quick response because all I could do at the time was wait. I felt relaxed when I read the fax. This is the second comet for me, but I can't feel pride in it. I feel terribly relieved that it was not a mistake. I may feel the same way even if I find more comets.

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Steven L. Renshaw

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