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

C/2017 T3 (ATLAS) at perigee

Dominic Ford, Editor
From the Comets feed

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Comet C/2017 T3 (ATLAS) will make its closest approach to the Earth, at a distance of 1.35 AU.

From Fairfield the 2018 apparition of C/2017 T3 (ATLAS) will progress as follows:

Begin typing the name of a town near to you, and then select the town from the list of options which appear below.
18 Jul 2018 – C/2017 T3 (ATLAS) at perihelion
22 Jul 2018 – C/2017 T3 (ATLAS) reaches its brightest
01 Aug 2018 – C/2017 T3 (ATLAS) at perigee
11 Jul 2018OrionNot observable
13 Jul 2018MonocerosNot observable
15 Jul 2018MonocerosNot observable
17 Jul 2018MonocerosNot observable
19 Jul 2018MonocerosNot observable
21 Jul 2018Canis MajorNot observable
23 Jul 2018Canis MajorNot observable
25 Jul 2018Canis MajorNot observable
27 Jul 2018PuppisNot observable
29 Jul 2018PuppisNot observable
31 Jul 2018PuppisNot observable
02 Aug 2018PuppisNot observable
04 Aug 2018PyxisNot observable
06 Aug 2018PyxisNot observable
08 Aug 2018PyxisNot observable
10 Aug 2018PyxisNot observable
12 Aug 2018AntliaNot observable
14 Aug 2018AntliaNot observable
16 Aug 2018AntliaNot observable
18 Aug 2018AntliaNot observable
20 Aug 2018AntliaNot observable

A more detailed table of C/2017 T3 (ATLAS)'s position on each night is available here. A diagram of the orbit of C/2017 T3 (ATLAS) is available here.

Finder chart

The chart below shows the path of C/2017 T3 (ATLAS) 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 T3 (ATLAS) is currently available.

The comet's position at perihelion will be:

Object Right Ascension Declination Constellation Magnitude
Comet C/2017 T3 (ATLAS) 08h09m20s -20°51' Puppis 8.7

The coordinates are given in J2000.0.

The sky on 01 August 2018
Twilight ends
Twilight begins

19-day old moon
Waning Gibbous


19 days old

Rise Culm. Set
Mercury 07:03 13:42 20:20
Venus 09:41 15:52 22:03
Moon 22:58 04:15 10:00
Mars 20:13 00:41 05:04
Jupiter 13:50 18:58 00:11
Saturn 17:47 22:25 03:08
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 03 Mar 2021.

Image credit

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






Color scheme