Electronic Telegram No. 5258
Central Bureau for Astronomical Telegrams
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Prepared using the Tamkin Foundation Computer Network


COMET C/1808 R1 (PONS)
     M. Meyer (Limburg, Germany) and G. W. Kronk (Belleville, IL, USA) report
the derivation of positions (tabulated below) from altitude and azimuth data
contained in contemporary manuscript letters of a comet discovered visually
in Sept. 1808 by Jean-Louis Pons (Marseille Observatory) using presumably his
"Grand Chercheur" telescope having a field-of-view of roughly 3 degrees (but
aperture unknown; cf. Roemer 1960, ASP Leaflet No. 371).  This comet was not
well-documented in the 19th-century astronomical literature, and it thus
never received even an X/ designation.

     1808 UT             R.A. (2000) Decl.       Mag.   Observer
                       h  m           d  '
     Sep. 11.8832     6 11.1       +84 19         9     Pons
          12.8818    10 22.2       +88 26                 "
          13.9018    15 50.0       +85 04                 "
          14.8733    16 32.6       +80 23                 "
          15.8691    16 47.3       +75 21                 "
          16.9239    17 00.4       +70 24                 "
          16.9875    16 57         +70 43                 "
          18.9337    17 05.4       +62 01                 "

In researching their new book (Kronk and Meyer 2023, *Catalog of Unconfirmed
Comets*, Vol. 1, pp. 77-80, published by Springer), they noticed a brief
published mention of the comet by L. Schulhof (1885, A.N. 113, 143) and a
summary of known information on the comet by C. G. Bigourdan (1899, Bull.
Astronomique 16, 62).  Bigourdan published a letter written on 1808 Sept. 16
from J. J. C. Thulis (Marseille Observatory director) to J. B. J. Delambre at
Paris Observatory with discovery information on the comet, and Bigourdan
noted the existence of letters written by B. A. von Lindenau (director of the
Seeburg Observatory) to several other astronomers about the comet.  Kronk
found Lindenau's correspondence at the Akademie der Wissenschaften zu
Goettingen; Lindenau had received more information from Pons than others had
apparently received, and that information in the Lindenau letters allowed
Meyer and Kronk to derive the approximate positions tabulated above; the
second Sept. 16 observation appears to be quite poor.  The comet was only
said to be "small and faint", and a total visual magnitude of 8-9 given is
an educated guess as to the comet's brightness.
     The following parabolic orbital elements by S. Nakano (Central Bureau)
are from 7 observations spanning 1808 Sept. 11-18 (mean residual 0.16 degree).

     T = 1808 Sept.14.1660 TT         Peri. =  32.0631
                                      Node  =  24.5104  2000.0
     q = 1.062224 AU                  Incl. = 132.9718


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2023 CBAT
2023 May 16                      (CBET 5258)              Daniel W. E. Green