None available.

C/2017 E1 (Borisov) at perihelion

Dominic Ford, Editor
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The sky at

Comet C/2017 E1 (Borisov) will make its closest approach to the Sun, at a distance of 0.90 AU.

From Ashburn the 2017 apparition of C/2017 E1 (Borisov) will progress as follows:

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10 Apr 2017 – C/2017 E1 (Borisov) at perihelion
20 Mar 2017AquariusNot observable
22 Mar 2017AquariusNot observable
24 Mar 2017AquariusNot observable
26 Mar 2017AquariusNot observable
28 Mar 2017AquariusNot observable
30 Mar 2017AquariusNot observable
01 Apr 2017AquariusNot observable
03 Apr 2017AquariusNot observable
05 Apr 2017AquariusNot observable
07 Apr 2017AquariusNot observable
09 Apr 2017AquariusNot observable
11 Apr 2017PiscesNot observable
13 Apr 2017PiscesNot observable
15 Apr 2017PiscesNot observable
17 Apr 2017PiscesNot observable
19 Apr 2017PiscesNot observable
21 Apr 2017PiscesNot observable
23 Apr 2017PiscesNot observable
25 Apr 2017PiscesNot observable
27 Apr 2017PiscesNot observable
29 Apr 2017PiscesNot observable

A more detailed table of C/2017 E1 (Borisov)'s position on each night is available here. A diagram of the orbit of C/2017 E1 (Borisov) 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 8° above the horizon at dawn.

Finder chart

The chart below shows the path of C/2017 E1 (Borisov) 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/2017 E1 (Borisov) is currently available.

The comet's position at perihelion will be:

Object Right Ascension Declination Constellation Magnitude
Comet C/2017 E1 (Borisov) 22h43m30s -03°28' Aquarius 9.4

The coordinates are given in J2000.0.

The sky on 10 April 2017
Twilight ends
Twilight begins

13-day old moon
Waxing Gibbous


13 days old

Rise Culm. Set
Mercury 07:02 13:59 20:56
Venus 05:19 11:35 17:51
Moon 19:25 00:30 06:33
Mars 08:06 15:13 22:20
Jupiter 19:14 01:04 06:49
Saturn 00:58 05:45 10:31
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 18 Jul 2020.

Image credit

None available.




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