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Comet 108P/CIFFREO (= 1985 V1 = 1992 S1)

Discovery: CBET 4136

Jacqueline Ciffreo (Caussols) discovered this comet on 1985 November 8.10 on plates exposed with the 0.9-m Schmidt. She described it as diffuse and estimated the magnitude as 10. She obtained a further image on November 8.11. M. Koishikawa (Sendai Observatory, Ayashi Station) confirmed the discovery on November 8.81 when the comet was located at the edge of a photographic plate obtained using a 300mm lens.

Observations within the week following the discovery revealed the comet's magnitude was slightly brighter than 12, with a coma about 2.5 arc minutes across and a tail two arc minutes long.

Recovery:

The comet was next expected to return to perihelion in early 1993. J. V. Scotti (Lunar and Planetary Laboratory, Arizona, USA) was using the Spacewatch telescope at Kitt Peak when he recovered the comet on 1992 September 24. He then noted the coma was 15 arc seconds across, while the tail extended 0.36 arc minute toward the west. From observations on that night, as well as on the 25th, he noted a total magnitude of 18.0 and a nuclear magnitude of 20.6. His precise positions indicated the predicted perihelion date needed a correction of +0.6 day, making it 1993 January 23.06. Following the announcement T. Seki (Geisei, Japan) found images on plates exposed on August 26, September 4 and 5. The comet was followed until 1993 February 26, when Scotti photographed it. He then determined the magnitude as 16.5.

Photometric data obtained by use of FOCAS-II software

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

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

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

108P          31/12/2014 22:30:45  16.71  15.87  15.19  14.84  14.62  14.52   4.5  17.0  B96

108P          31/12/2014 22:30:45*  0.06   0.06   0.14   0.12   0.11   0.10     4   3.5  USN

108P          06/02/2015 22:11:20  18.10  17.62  17.38                        3.3  18.0  B96

108P          06/02/2015 22:11:20*  0.18   0.25   0.23                          5   3.9  USN

108P          07/01/2022 04:01:52  17.36  16.43  15.88  15.62  15.41  15.18   4.2  19.2  Z08

108P          07/01/2022 04:01:52*  0.10   0.09   0.11   0.06   0.05   0.07     2   2.8  Gai

108P          24/01/2022 21:14:03  17.68  16.70  16.25  15.89  15.71  15.68   5.8  18.2  B96

108P          24/01/2022 21:14:03*  0.03   0.10   0.04   0.07   0.02   0.08     2   4.0  Gai

COMET         UTC                   DELTA    R    APER    Mag   AfRho   +/-   Log   Obs

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

108P          31/12/2014 22:30:45    0.92   1.85  29.99  15.29    5     21     5  1.329  B96

108P          06/02/2015 22:11:20    1.30   2.01  21.18  17.60    3      6     2  0.777  B96

108P          07/01/2022 04:01:52    1.06   2.02  26.00  16.15    4     15     4  1.183  Z08

108P          24/01/2022 21:14:03    1.21   2.11  22.86  16.63    6     14     2  1.143  B96