© Andy Roberts 1997. Pictured comet is C/1995 O1 Hale-Bopp.

73P/Schwassmann-Wachmann at perihelion

Dominic Ford, Editor
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Comet 73P/Schwassmann-Wachmann will make its closest approach to the Sun, at a distance of 0.97 AU.

From Fairfield the 2022 apparition of 73P/Schwassmann-Wachmann will progress as follows:

Begin typing the name of a town near to you, and then select the town from the list of options which appear below.
24 Aug 2022 – 73P/Schwassmann-Wachmann at perihelion
03 Aug 2022VirgoNot observable
05 Aug 2022VirgoNot observable
07 Aug 2022VirgoNot observable
09 Aug 2022VirgoNot observable
11 Aug 2022VirgoNot observable
13 Aug 2022VirgoNot observable
15 Aug 2022VirgoNot observable
17 Aug 2022VirgoNot observable
19 Aug 2022VirgoNot observable
21 Aug 2022VirgoNot observable
23 Aug 2022VirgoNot observable
25 Aug 2022VirgoNot observable
27 Aug 2022VirgoNot observable
29 Aug 2022VirgoNot observable
31 Aug 2022VirgoNot observable
02 Sep 2022VirgoNot observable
04 Sep 2022LibraNot observable
06 Sep 2022LibraNot observable
08 Sep 2022LibraNot observable
10 Sep 2022LibraNot observable
12 Sep 2022LibraNot observable

A more detailed table of 73P/Schwassmann-Wachmann's position on each night is available here. A diagram of the orbit of 73P/Schwassmann-Wachmann is available here.

At the moment of perihelion it will not be observable – it will reach its highest point in the sky during daytime and will be no higher than 6° above the horizon at dusk.

Finder chart

The chart below shows the path of 73P/Schwassmann-Wachmann over the course of its apparition, as calculated from the orbital elements published by the Minor Planet Center (MPC). It is available for download, either on dark background, in PNG, PDF or SVG formats, or on a light background, in PNG, PDF or SVG formats. It was produced using StarCharter.

Comet brightnesses

Comets are intrinsically highly unpredictable objects, since their brightness depends on the scattering of sunlight from dust particles in the comet's coma and tail. This dust is continually streaming away from the comet's nucleus, and its density at any particular time is governed by the rate of sublimation of the ice in the comet's nucleus, as it is heated by the Sun's rays. It also depends on the amount of dust that is mixed in with that ice. This is very difficult to predict in advance, and can be highly variable even between successive apparitions of the same comet.

In consequence, while the future positions of comets are usually known with a high degree of confidence, their future brightnesses are not. For most comets, we do not publish any magnitude estimates at all. For the few comets where we do make estimates, we generally prefer the BAA's magnitude parameters to those published by the Minor Planet Center, since they are typically updated more often.

Based on the magnitude parameters published for this comet by the BAA Comet Section, we estimate that it may be around mag 11 at perihelion. This estimate is based on observations that the BAA has received from amateur astronomers, assuming that its current level of activity will remain constant.

You will probably require a telescope to see this comet. It is unlikely to be visible through bird-watching binoculars, and even less likely to be visible to the unaided eye.

The comet's position at perihelion will be:

Object Right Ascension Declination Constellation Magnitude
Comet 73P/Schwassmann-Wachmann 13h38m10s 13°41'S Virgo 11.1

The coordinates are given in J2000.0.

The sky on 24 August 2022
Twilight ends
Twilight begins

27-day old moon
Waning Crescent


27 days old

Rise Culm. Set
Mercury 08:35 14:35 20:35
Venus 04:50 11:55 19:01
Moon 03:03 10:59 18:46
Mars 23:31 06:45 13:59
Jupiter 21:04 03:12 09:20
Saturn 19:13 00:19 05:25
All times shown in EDT.


This event was automatically generated on the basis of orbital elements published by the Minor Planet Center (MPC) , and is updated whenever new elements become available. It was last updated on 15 Mar 2021.

Image credit

© Andy Roberts 1997. Pictured comet is C/1995 O1 Hale-Bopp.






Color scheme