September 21
I saw the gegenschein (counter glow). With Typhoon No. 13
(Shanshan) gone, autumn weather has suddenly arrived. The lingering autumn
rain front has moved northward and the long period of rainy weather has
ended. The sky has been blue and transparent since this morning, a typical
autumn day. It also means the arrival of an observing season.
Geisei's 60cm reflector is not in perfect working order,
but somehow I managed
to turn it to 177P (Barnard 2) in the northern sky. The coma remains diffuse at 11th magnitude. In photographs it shows a sharp nucleus with m2 being 15th magnitude. The drive motor of the 60cm telescope stopped intermittently, which prevented precise measurements. However, if the object was bright, I could visually confirm it by the 20cm refractor mounted on it. After midnight, I moved to the third observatory building and swept the autumn eastern sky. This was the first sweeping in a while.
Looking up, I saw a broad glow looking like a second Milky
Way slightly south of the zenith. In the northern sky the Milky Way from
Cygnus to Cassiopeia was magnificent, but this southern "Milky Way"
might have been the gegenschein, a rather unusual sight.
It readily caught my eye, but was quite faint; 1/3 to 1/5
the brightness of the faintest portion of the Milky Way. The glow of the
gegenschein was quite large and at least 10 degrees across. It was located
midway between Pegasus near the zenith and Fomalhaut in the south, definitely
in opposition to the sun. The glow comes from dust particles in the Solar
System including minor planets. A number of mercury lamps at the distant
southern horizon interfered with observing the gegenshein's faint glow,
but I was able to confirm the glow shifting slightly to the west after
midnight. I have been able to sight the gegenschein almost every night
since I started observing at Geisei 30 years ago and photographed it often.
I searched the sky from Gemini to Leo in the eastern sky
and before the dawn reached Hydra, east of Canis Major, where the Kreutz
group comets would appear. I felt as if the observatory and I had plunged
into space. I was completely immersed in a world belonging to the stars.
