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BAA Observing calendar

C/2017 M4 (ATLAS) reaches its brightest

Friday, 2019, May 3 - 02:00

Comet C/2017 M4 (ATLAS) is forecast to reach its brightest, at around mag 12.8. It will lie at a distance of 3.41 AU from the Sun, and at a distance of 2.51 AU from the Earth.

From London however, it will not be readily observable since it will lie so far south that it will never rise more than 1° above the horizon.

For more information about its path across the sky, see's ephemeris page for comet C/2017 M4 (ATLAS).

This event was automatically generated on the basis of orbital elements published by the Minor Planet Center (MPC), and is updated daily (last update, 20 Oct 2018).

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
Dark-on-light PNG image PDF document

The exact position of comet C/2017 M4 (ATLAS) will be:

Object Right Ascension Declination Constellation Magnitude
Comet C/2017 M4 (ATLAS) 16h27m00s -37°28' Scorpius 12.8

The coordinates are given in J2000.0.

This entry in the observing calendar was provided by