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

21P/Giacobini-Zinner reaches its brightest

Dominic Ford, Editor
From the Comets feed

Comet 21P/Giacobini-Zinner is forecast to reach its brightest, at around mag 7.4. It will lie at a distance of 1.01 AU from the Sun, and at a distance of 0.38 AU from the Earth.

From Cambridge, it will be visible in the dawn sky, rising at 22:36 (EDT) – 7 hours and 40 minutes before the Sun – and reaching an altitude of 63° above the eastern horizon before fading from view as dawn breaks at around 05:07.

Begin typing the name of a town near to you, and then select the town from the list of options which appear below.

For more information about its path across the sky, see In-The-Sky.org's ephemeris page for comet 21P/Giacobini-Zinner.

This event was automatically generated on the basis of orbital elements published by the Minor Planet Center (MPC), and is updated daily (last update, 24 Mar 2019).

Note that the future positions of comets are typically known with a high degree of confidence, but their brightnesses are often much more unpredictable, since it is impossible to predict with certainty how they will respond as they move closer to the Sun. Magnitude estimates should be assumed to be highly provisional more than a few weeks in advance.

Printable finder charts

Light-on-dark PNG image PDF document
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The exact position of comet 21P/Giacobini-Zinner will be:

Object Right Ascension Declination Constellation Magnitude
Comet 21P/Giacobini-Zinner 05h48m30s +33°43' Auriga 7.4

The coordinates are given in J2000.0.

The sky on 10 September 2018
Twilight ends
Twilight begins

1-day old moon
Waxing Crescent


1 day old

Rise Culm. Set
Mercury 05:27 12:07 18:48
Venus 10:10 15:13 20:16
Moon 07:18 13:36 19:54
Mars 17:14 21:36 02:01
Jupiter 11:29 16:29 21:30
Saturn 15:00 19:34 00:12
All times shown in EDT.


The circumstances of this event were computed using the DE405 planetary ephemeris published by the Jet Propulsion Laboratory (JPL).

This event was automatically generated by searching the ephemeris for planetary alignments which are of interest to amateur astronomers, and the text above was generated based on an estimate of your location.

Image credit

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




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