61P/Shajn-Schaldach (0061P)
TRY AGAIN 2028
Type: Periodic
Perihelion date: 24 October 2022
Perihelion distance (q): 2.1
Aphelion distance (Q) : 5.2
Period (years): 7.1
Eccentricity (e): 0.42
Inclination (i): 6.0
JPL orbit diagram
COBS lightcurve
The comet was discovered on 18 September 1949 on a photographic plate by
Pelageja F. Shajn at the Simeiz Observatory, Crimea, part of the Crimean
Astrophysical Observatory. It was also discovered independently two days later by
Robert D. Schaldach at the Lowell Observatory in Arizona, US, also on a
photographic plate. Shajn then found evidence of the comet on earlier photographs
taken on August 28 and September 4.
The first computations of the comet's orbit gave a perihelion date of between
December 1949 and October 1950 with a periodicity of 7.76 years. After taking into
account perturbations due a close approach to Jupiter the next perihelion was
calculated to be on 15 March 1957 but in that year it was never found. It was also not
discovered on its next predicted appearance in 1964. The most likely explanation for
the two failures was the comet's faintness.
It was, however, re-located on 29 September 1971 by Charles T. Kowal of the
Department of Astrophysics, California Institute of Technology, US, using the 122 cm
Palomar Schmidt telescope, who estimated its brightness at a faint magnitude of 16.
Other astronomers confirmed the sighting. The comet was successfully observed on
its subsequent returns in 1979, 1986, 1993, 2001 and 2008.
Observations (VEMag = visual equivalent magnitude)
Date
10x10 mag
Error
VEmag
Coma '
17-Aug-15
17.19
0.03
15.5
0.3
25-Aug-15
17.02
0.01
15.4
0.4
07-Sep-15
16.75
0.02
15.3
0.3
14-Sep-15
16.66
0.04
15.0
0.4
22-Sep-15
16.59
0.01
15.1
0.3
09-Oct-15
16.37
0.01
14.6
0.3
20-Oct-15
16.24
0.01
14.1
0.8
02-Nov-15
16.21
0.01
14.3
0.5
13-Nov-15
16.31
0.02
14.0
0.6
03-Dec-15
16.97
0.01
14.6
0.4
11-Dec-15
17.17
0.03
14.7
0.5
05-Aug-22
17.7
0.4
24-Aug-22
17.2
0.4
31-Aug-22
17.3
0.4
06-Sep-22
17.0
0.4
21-Sep-22
16.1
0.6
17-Jan-23
18.6
0.4
20-Feb-23
19.1
0.4
15-Mar-23
19.6
0.4