The evolution of the 1892 outburst from 1892 Nov 10 to 1892 Dec 8
 


The following four links are to high-resolution scanned images of the 1892 outburst of 17P/Holmes. The first image was taken on November 10th, three days after discovery. They show the striking similarities between the 1892 and 2007 outbursts. However, they also suggest that, unlike what was previously supposed, the outburst was not discovered immediately, but that rather that the images are consistent with an outburst that had evolved for several days. The explanation for the delay in discovering is simple: Full Moon had occurred on the afternoon of November 4th and Holmes's observations of M31 were carried out at the first opportunity when there was no bright moon in the sky for a short interval at the start of the night. Probably the outburst itself had happened as early as November 1st and was hidden in the moonlit sky for several days.
 
The blow-up of the 1892 Nov 10 image also shows a massive tail disconnection event similar to the November 2007 event, echoing the uncanny parallels between the two outbursts. Were these parallels to continue we might expect a second outburst 70 days after the first, nominally on 2008 Jan 03 but. From the size of the coma at discovery it seems that Edwin Holmes actually discovered the outburst about 5 days after it occurred, the second outburst might be expected in late December, just after Christmas.

Plate 102
10 November 1892 at 7h 45m P.S.T.
Exposure 3h 0m
Comet - 8' diameter with outer ring of 19' diameter
http://www.skepticus.com/images/Holmes%20Plate102s.jpg
 
Plate 103
10 November 1892 at 7h 45m P.S.T.
Exposure 3h 0m
(enlargements of Plate 102)
http://www.skepticus.com/images/Holmes%20Plate103s.jpg
 
Plate 104
21 November 1892 at 9h 32m P.S.T.
Exposure 1h 15m
Comet - 19' diameter
http://www.skepticus.com/images/Holmes%20Plate104s.jpg
 
Plate 105
8 December 1892 at 6h 57m P.S.T.
Exposure 1h 15m
Comet - 25' diameter
http://www.skepticus.com/images/Holmes%20Plate105s.jpg


Why did Edwin Holmes not see the outburst before November 7th?