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

C/2015 ER61 (PANSTARRS) at perihelion

Dominic Ford, Editor
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The sky at

Comet C/2015 ER61 (PANSTARRS) will make its closest approach to the Sun, at a distance of 1.05 AU.

From Cambridge the 2017 apparition of C/2015 ER61 (PANSTARRS) will progress as follows:

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20 Apr 2017 – C/2015 ER61 (PANSTARRS) at perigee
04 May 2017 – C/2015 ER61 (PANSTARRS) reaches its brightest
10 May 2017 – C/2015 ER61 (PANSTARRS) at perihelion
19 Apr 2017AquariusNot observable
21 Apr 2017AquariusNot observable
23 Apr 2017AquariusNot observable
25 Apr 2017AquariusNot observable
27 Apr 2017AquariusNot observable
29 Apr 2017AquariusNot observable
01 May 2017PiscesNot observable
03 May 2017PiscesNot observable
05 May 2017PiscesNot observable
07 May 2017PiscesNot observable
09 May 2017PiscesNot observable
11 May 2017PiscesNot observable
13 May 2017PiscesNot observable
15 May 2017PiscesNot observable
17 May 2017PiscesNot observable
19 May 2017PiscesNot observable
21 May 2017PiscesNot observable
23 May 2017PiscesNot observable
25 May 2017PiscesNot observable
27 May 2017PiscesNot observable
29 May 2017PiscesNot observable

A more detailed table of C/2015 ER61 (PANSTARRS)'s position on each night is available here. A diagram of the orbit of C/2015 ER61 (PANSTARRS) 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 12° above the horizon at dawn.

Finder chart

The chart below shows the path of C/2015 ER61 (PANSTARRS) 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/2015 ER61 (PANSTARRS) is currently available.

The comet's position at perihelion will be:

Object Right Ascension Declination Constellation Magnitude
Comet C/2015 ER61 (PANSTARRS) 23h35m20s +02°46' Pisces 7.9

The coordinates are given in J2000.0.

The sky on 10 May 2017
Twilight ends
Twilight begins

14-day old moon
Waxing Gibbous


14 days old

Rise Culm. Set
Mercury 04:41 11:11 17:41
Venus 03:44 09:56 16:08
Moon 19:47 00:14 05:38
Mars 06:41 14:16 21:51
Jupiter 16:36 22:24 04:15
Saturn 22:36 03:17 07:54
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 30 Oct 2020.

Image credit

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






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