Comet 45P/Honda-Mrkos-Pajdusakova reaches peak brightness

Dominic Ford, Editor
From the Comets feed


Comet 45P/Honda-Mrkos-Pajdusakova is forecast to reach the brightest point in its 2027 apparition on 25 August. At that time, it will lie at a distance of 0.57 AU from the Sun, and at a distance of 0.92 AU from the Earth.

From South El Monte on 25 August it will not be observable – it will reach its highest point in the sky during daytime and will be no higher than 18° above the horizon at dawn.

The events that comprise the 2027 apparition of 45P/Honda-Mrkos-Pajdusakova are as follows:

Date Event
25 Aug 2027Comet 45P/Honda-Mrkos-Pajdusakova reaches peak brightness
31 Aug 2027Comet 45P/Honda-Mrkos-Pajdusakova passes perihelion

The table below lists the times when 45P/Honda-Mrkos-Pajdusakova will be visible from South El Monte day-by-day through its apparition:

Date Constellation Comet visibility
04 Aug 2027TaurusVisible from 04:26 until 04:56
Highest at 04:56, 28° above E horizon
06 Aug 2027TaurusVisible from 04:34 until 04:58
Highest at 04:58, 27° above E horizon
08 Aug 2027OrionVisible from 04:41 until 05:00
Highest at 05:00, 26° above E horizon
10 Aug 2027OrionVisible from 04:49 until 05:02
Highest at 05:02, 25° above E horizon
12 Aug 2027GeminiVisible from 04:56 until 05:04
Highest at 05:04, 23° above E horizon
14 Aug 2027GeminiVisible from 05:02 until 05:05
Highest at 05:05, 23° above E horizon
16 Aug 2027GeminiNot observable
18 Aug 2027GeminiNot observable
20 Aug 2027GeminiNot observable
22 Aug 2027GeminiNot observable
24 Aug 2027GeminiNot observable
26 Aug 2027CancerNot observable
28 Aug 2027CancerNot observable
30 Aug 2027CancerNot observable
01 Sep 2027CancerNot observable
03 Sep 2027CancerNot observable
05 Sep 2027CancerNot observable
07 Sep 2027CancerNot observable
09 Sep 2027CancerNot observable
11 Sep 2027LeoNot observable
13 Sep 2027LeoNot observable

A more detailed table of 45P/Honda-Mrkos-Pajdusakova's position on each night is available here. A diagram of the orbit of 45P/Honda-Mrkos-Pajdusakova is available here.

Finder chart

The chart below shows the path of 45P/Honda-Mrkos-Pajdusakova 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 8 on 25 August 2027. This estimate is based on observations that the BAA has received from amateur astronomers, assuming that its current level of activity will remain constant.

This comet is not expected to be visible to the naked eye, but might be visible through bird-watching binoculars.

The comet's position on 25 August 2027 will be:

Object Right Ascension Declination Constellation Magnitude
Comet 45P/Honda-Mrkos-Pajdusakova 07h57m20s 18°34'N Cancer 7.9

The coordinates are given in J2000.0.

The sky on 25 Aug 2027

The sky on 25 August 2027
Sunrise
06:17
Sunset
19:27
Twilight ends
20:55
Twilight begins
04:49


Waning Crescent

36%

23 days old

Planets
Rise Culm. Set
Mercury 07:23 13:44 20:05
Venus 06:36 13:09 19:41
Moon 23:30 06:58 14:30
Mars 10:32 16:08 21:44
Jupiter 06:39 13:09 19:40
Saturn 21:58 04:23 10:47
All times shown in PDT.

Source

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 Dec 2025.

Image credit

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

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