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

Comet C/2023 P1 (Nishimura) passes perihelion

Dominic Ford, Editor
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Comet C/2023 P1 (Nishimura) will make its closest approach to the Sun on 17 September, at a distance of 0.23 AU.

From San Diego on the day of perihelion it will not be readily observable since it will be very close to the Sun, at a separation of only 12° from it.

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The events that comprise the 2023 apparition of C/2023 P1 (Nishimura) are as follows:

Date Event
12 Sep 2023Comet C/2023 P1 (Nishimura) passes perigee
17 Sep 2023Comet C/2023 P1 (Nishimura) passes perihelion

The table below lists the times when C/2023 P1 (Nishimura) will be visible from San Diego day-by-day through its apparition:

Date Constellation Comet visibility
27 Aug 2023CancerNot observable
29 Aug 2023CancerNot observable
31 Aug 2023CancerNot observable
02 Sep 2023CancerNot observable
04 Sep 2023LeoNot observable
06 Sep 2023LeoNot observable
08 Sep 2023LeoNot observable
10 Sep 2023LeoNot observable
12 Sep 2023LeoNot observable
14 Sep 2023LeoNot observable
16 Sep 2023VirgoNot observable
18 Sep 2023VirgoNot observable
20 Sep 2023VirgoNot observable
22 Sep 2023VirgoNot observable
24 Sep 2023VirgoNot observable
26 Sep 2023VirgoNot observable
28 Sep 2023VirgoNot observable
30 Sep 2023VirgoNot observable
02 Oct 2023VirgoNot observable
04 Oct 2023VirgoNot observable
06 Oct 2023VirgoNot observable

A more detailed table of C/2023 P1 (Nishimura)'s position on each night is available here. A diagram of the orbit of C/2023 P1 (Nishimura) is available here.

Finder chart

The chart below shows the path of C/2023 P1 (Nishimura) 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 2 on 17 September 2023. This estimate is based on observations that the BAA has received from amateur astronomers, assuming that its current level of activity will remain constant.

The comet's position at perihelion will be:

Object Right Ascension Declination Constellation Magnitude
Comet C/2023 P1 (Nishimura) 12h23m10s 7°45'N Virgo 2.1

The coordinates are given in J2000.0.

The sky on 17 Sep 2023

The sky on 17 September 2023
Twilight ends
Twilight begins

2-day old moon
Waxing Crescent


2 days old

Rise Culm. Set
Mercury 05:16 11:40 18:04
Venus 03:35 10:07 16:40
Moon 08:50 14:38 20:18
Mars 08:02 13:52 19:42
Jupiter 21:13 03:55 10:38
Saturn 17:49 23:19 04:49
All times shown in PDT.


Never attempt to point a pair of binoculars or a telescope at an object close to the Sun. Doing so may result in immediate and permanent blindness.


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 19 Sep 2023.

Image credit

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


San Diego



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