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7P/PONS-WINNECKE - (=1819 L1 = 1858 E1 = 1869 G1)

Photometric data obtained by use of FOCAS-II software

                                   10x10  20x20  30x30  40x40  50x50  60x60   SNR   SB   COD

OBJECT        DATE       TIME        +/-    +/-    +/-    +/-    +/-    +/-     N  FWHM  CAT

------------  ---------- --------  -----  -----  -----  -----  -----  -----  ----  ----  ---

7P            17/04/2021 01:18:40  15.71  15.22  15.02  14.86  14.84  14.89   6.1  16.4  B96

7P            17/04/2021 01:18:40*  0.11   0.18   0.11   0.20   0.31   0.37     3   3.9  Gai

7P            08/06/2021 10:22:22  14.50  13.89  13.60  13.41  13.26  13.15  20.9  19.7  X02

7P            08/06/2021 10:22:22*  0.01   0.01   0.02   0.03   0.04   0.04     3   2.9  Gai

                                                                     AFRHO         LOG

COMET         UTC                   DELTA    r    BOX "   MAG   RSR    CM    +/-  AFRHO  OBS

------------  -------------------   -----  -----  -----  -----  ---  -----  ----  -----  ---

7P            17/04/2021 01:18:40    0.68   1.33  40.72  14.94    6      8     1  0.914  B96

7P            08/06/2021 10:22:22    0.44   1.24  62.24  13.09   21     17     1  1.231  X02

Discovery:

Jean Louis Pons (Observatory of Marseille, France) discovered this comet on 1819 June 12 in the western sky. The comet was then in Leo and was described as small and tailless, with a central condensation with a small condensation.  Pons said it was not a naked eye object, but it did brighten in the following days of his discovery. The comet was particularly well placed during its discovery apparition, but its most significant event, a close approach to Earth on 1819 August 21 (0.1318 AU) was missed. Following its discovery on June 12 the comet was followed until lost in evening twilight after July 22. The comet took on a southwestern motion thereafter, and was in southern skies by the time it emerged from the sun's glare. On August 31 it reached its most southerly declination of -43.6°.

F.A.T. Winnecke (Bonn, Germany) accidently rediscovered this comet in the morning sky on 1858 march 9.06 UT, he confirmed this comet was moving when it was seen on march 9.16. Winnecke discribed it as a pale and diffuse nebolosity, about 3’ across, with n o trace of nucleus.  The comet brightened slowly troughout most of march as it approached both sun and earth. The comet was near a 7-th magnitude star on the 12-th, which K.T.R. Luther (Bilk, Germany) said caused the comet to appear small and faint.

Since the 1869 appearance, the comet has only been missed on three occasions (1880, 1904, and 1957).

Perturbations by Jupiter have steadily increased the comet's orbital period and perihelion distance since its first successfully predicted recovery in 1869. Close approaches occurred in 1882 November (0.44 AU), 1894 November (0.45 AU), 1906 December (0.42 AU), 1918 November (0.36 AU), and 1930 July (0.47 AU). In 1869 the period was 5.59 years and perihelion distance was 0.78 AU, while in 1996 they were 6.37 years and 1.26 AU.

The 1927 appearance was the best since the comet's discovery. It passed only 0.0404 AU from Earth on 1927 June 26 and attained a maximum brightness of magnitude 3.5.

For a few years the perturbations by Jupiter enabled strong displays of meteors to be seen around June 28 of the years the comet arrived at perihelion. The meteor stream became known as the June Boötids, but was occasionally also known as the Pons-Winneckids. Very strong displays were noticed in 1916, 1921, and 1927, which also marked three consecutive perihelion returns for the comet. In the latter year, rates reached 500 per hour at one point. Continued perturbations by Jupiter have moved the comet and its meteor stream into slightly different orbits and the June Boötids have been hardly noticeable in recent years.

Bron: Kronk’s Cometography                                                                                                             last updated: 2021-04-20