Comet C/2011 C1 (McNaught) passes perihelion

Dominic Ford, Editor
From the Comets feed


Comet C/2011 C1 (McNaught) will make its closest approach to the Sun on 19 April, at a distance of 0.90 AU.

From South El Monte on the day of perihelion it will be visible in the dawn sky, rising at 03:12 (PDT) – 3 hours and 3 minutes before the Sun – and reaching an altitude of 24° above the eastern horizon before fading from view as dawn breaks at around 05:12.

The events that comprise the 2011 apparition of C/2011 C1 (McNaught) are as follows:

Date Event
19 Apr 2011Comet C/2011 C1 (McNaught) passes perihelion

The table below lists the times when C/2011 C1 (McNaught) will be visible from South El Monte day-by-day through its apparition:

Date Constellation Comet visibility
29 Mar 2011AquilaVisible from 04:57 until 05:42
Highest at 05:42, 30° above SE horizon
31 Mar 2011AquariusVisible from 04:58 until 05:39
Highest at 05:39, 30° above SE horizon
02 Apr 2011AquariusVisible from 04:59 until 05:37
Highest at 05:37, 29° above SE horizon
04 Apr 2011AquariusVisible from 04:59 until 05:34
Highest at 05:34, 28° above SE horizon
06 Apr 2011AquariusVisible from 05:00 until 05:31
Highest at 05:31, 28° above E horizon
08 Apr 2011AquariusVisible from 05:00 until 05:28
Highest at 05:28, 27° above E horizon
10 Apr 2011AquariusVisible from 05:00 until 05:25
Highest at 05:25, 27° above E horizon
12 Apr 2011AquariusVisible from 05:00 until 05:22
Highest at 05:22, 26° above E horizon
14 Apr 2011AquariusVisible from 05:00 until 05:19
Highest at 05:19, 26° above E horizon
16 Apr 2011PegasusVisible from 05:00 until 05:17
Highest at 05:17, 25° above E horizon
18 Apr 2011PegasusVisible from 05:00 until 05:14
Highest at 05:14, 25° above E horizon
20 Apr 2011PegasusVisible from 04:59 until 05:11
Highest at 05:11, 24° above E horizon
22 Apr 2011PegasusVisible from 04:59 until 05:08
Highest at 05:08, 24° above E horizon
24 Apr 2011PegasusVisible from 04:58 until 05:06
Highest at 05:06, 23° above E horizon
26 Apr 2011PiscesVisible from 04:57 until 05:03
Highest at 05:03, 23° above E horizon
28 Apr 2011PiscesVisible from 04:56 until 05:01
Highest at 05:01, 23° above E horizon
30 Apr 2011PiscesVisible from 04:55 until 04:58
Highest at 04:58, 22° above E horizon
02 May 2011PegasusVisible from 04:54 until 04:56
Highest at 04:56, 22° above E horizon
04 May 2011PegasusVisible from 04:52 until 04:53
Highest at 04:53, 22° above E horizon
06 May 2011PegasusNot observable
08 May 2011PegasusNot observable

A more detailed table of C/2011 C1 (McNaught)'s position on each night is available here. A diagram of the orbit of C/2011 C1 (McNaught) is available here.

Finder chart

The chart below shows the path of C/2011 C1 (McNaught) 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.

No estimate for the brightness of comet C/2011 C1 (McNaught) is currently available.

The comet's position at perihelion will be:

Object Right Ascension Declination Constellation Magnitude
Comet C/2011 C1 (McNaught) 22h24m30s 4°18'N Pegasus 9.4

The coordinates are given in J2000.0.

The sky on 1 Jul 2025

The sky on 1 July 2025
Sunrise
05:41
Sunset
20:07
Twilight ends
21:51
Twilight begins
03:57


Waxing Crescent

43%

6 days old

Planets
Rise Culm. Set
Mercury 07:46 14:43 21:41
Venus 03:01 09:51 16:41
Moon 12:09 18:15 00:12
Mars 10:21 16:50 23:19
Jupiter 05:21 12:31 19:42
Saturn 00:22 06:21 12:20
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 23 Feb 2025.

Image credit

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

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