Home > Comet, Observing > 07/23/2020 – Ephemeris – The two tails of Comet NEOWISE

07/23/2020 – Ephemeris – The two tails of Comet NEOWISE

July 23, 2020

This is Bob Moler with Ephemeris for Thursday, July 23rd. Today the Sun will be up for 14 hours and 58 minutes, setting at 9:18, and it will rise tomorrow at 6:20. The Moon, 3 days past new, will set at 11:31 this evening.

Tonight Comet C/2020 F3 (NEOWISE) has moved so it is not below the bowl of the Big Dipper but more below the handle. It is dimming, so it is best found with optical aid like a pair of binoculars. Many pictures of it can be found now on the Internet and in print. Many photos show that the comet has two distinct tails. A broad whitish tail that we can see visually and a thin blue one separated by a slight angle. To the eye we see the broad tail which is made of dust. The particles are pushed away from the Sun by the force of sunlight itself. The blue tail is made of ionized gasses and pushed back by the solar wind. This tail leaves the comet’s head faster than the dust so the comet’s sideways motion to the Sun causes the tails to separate. The tail on the chart below closely matches the direction of the ion tail. The brighter dust tail is canted to the right.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.


Comet NEOWISE finder chart

Comet NEOWISE finder chart for tonight July 23, 2020 at 11 pm or about an hour and a half after sunset looking northwest under the Big Dipper. Created using Stellarium.

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