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

38P/Stephan-Oterma at perihelion

Dominic Ford, Editor
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Comet 38P/Stephan-Oterma will make its closest approach to the Sun, at a distance of 1.58 AU.

From Ashburn the 2018 apparition of 38P/Stephan-Oterma 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.
11 Nov 2018 – 38P/Stephan-Oterma at perihelion
21 Oct 2018GeminiVisible from 01:02 until 06:23
Highest at 06:00, 67° above S horizon
23 Oct 2018GeminiVisible from 00:58 until 06:25
Highest at 05:57, 67° above S horizon
25 Oct 2018GeminiVisible from 00:53 until 06:27
Highest at 05:54, 68° above S horizon
27 Oct 2018GeminiVisible from 00:49 until 06:29
Highest at 05:51, 68° above S horizon
29 Oct 2018GeminiVisible from 00:44 until 06:31
Highest at 05:48, 69° above S horizon
31 Oct 2018GeminiVisible from 00:39 until 06:33
Highest at 05:44, 69° above S horizon
02 Nov 2018GeminiVisible from 00:34 until 06:35
Highest at 05:41, 70° above S horizon
04 Nov 2018GeminiVisible from 00:29 until 05:37
Highest at 04:38, 71° above S horizon
06 Nov 2018GeminiVisible from 23:20 until 05:39
Highest at 04:34, 71° above S horizon
08 Nov 2018GeminiVisible from 23:15 until 05:41
Highest at 04:31, 72° above S horizon
10 Nov 2018GeminiVisible from 23:10 until 05:43
Highest at 04:27, 72° above S horizon
12 Nov 2018GeminiVisible from 23:04 until 05:45
Highest at 04:24, 73° above S horizon
14 Nov 2018GeminiVisible from 22:58 until 05:47
Highest at 04:20, 74° above S horizon
16 Nov 2018GeminiVisible from 22:53 until 05:49
Highest at 04:16, 74° above S horizon
18 Nov 2018GeminiVisible from 22:47 until 05:51
Highest at 04:12, 75° above S horizon
20 Nov 2018GeminiVisible from 22:41 until 05:53
Highest at 04:08, 76° above S horizon
22 Nov 2018GeminiVisible from 22:34 until 05:55
Highest at 04:04, 76° above S horizon
24 Nov 2018CancerVisible from 22:28 until 05:57
Highest at 04:00, 77° above S horizon
26 Nov 2018CancerVisible from 22:21 until 05:58
Highest at 03:56, 78° above S horizon
28 Nov 2018CancerVisible from 22:14 until 06:00
Highest at 03:51, 79° above S horizon
30 Nov 2018CancerVisible from 22:07 until 06:02
Highest at 03:46, 79° above S horizon

A more detailed table of 38P/Stephan-Oterma's position on each night is available here. A diagram of the orbit of 38P/Stephan-Oterma is available here.

At the moment of perihelion it will be visible in the morning sky, becoming accessible around 23:06, when it reaches an altitude of 21° above your eastern horizon. It will then reach its highest point in the sky at 04:25, 72° above your southern horizon. It will be lost to dawn twilight around 05:42, 65° above your south-western horizon.

Finder chart

The chart below shows the path of 38P/Stephan-Oterma 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 38P/Stephan-Oterma is currently available.

The comet's position at perihelion will be:

Object Right Ascension Declination Constellation Magnitude
Comet 38P/Stephan-Oterma 07h35m50s +21°34' Gemini 10.1

The coordinates are given in J2000.0.

The sky on 11 November 2018
Twilight ends
Twilight begins

4-day old moon
Waxing Crescent


4 days old

Rise Culm. Set
Mercury 08:49 13:25 18:00
Venus 04:56 10:18 15:41
Moon 10:32 15:21 20:11
Mars 13:31 18:47 00:04
Jupiter 07:45 12:41 17:37
Saturn 10:28 15:11 19:55
All times shown in EST.


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 Jan 2021.

Image credit

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






Color scheme