Skywatch Line for Wednesday and Thursday, April 10 and 11, 2024, written by Alan French

This is Dudley Observatory’s Skywatch Line for Wednesday and Thursday, April 10 and 11, 2024, written by Alan French.

The Sun rises at 6:21 A.M. on Wednesday and sets at 7:32 P.M. On Thursday it rises at 6:19 and sets at 7:34. This Thursday has just under 20 minutes more daylight than last Thursday.

Sky conditions were not perfect in New York for Monday’s eclipse, but many people got to see it, despite some clouds, and quite a few traveled north into the path of totality and were able to see the corona, the diamond ring, Bailey’s beads, and prominences. Against normal expectations, northern New England was one of the better viewing places. (The birds certainly noticed totality and maximum partial, singing like it was twilight.) The next total eclipse crossing the United States will not be until August 12, 2045.

The Moon, having reached new on April 8, is now moving toward first quarter. On Wednesday night as darkness falls, look for a slender crescent Moon in the western sky. Look for earthshine, the illumination of the dark portion of the Moon by light from the bright, almost full Earth, in its sky. At 8:15 P.M. the Moon will be 7% sunlit and 20 degrees above the horizon. Bright Jupiter will be 8 ½ degrees to the Moon’s lower left.

Comet 12P/Pons-Brooks will be to Jupiter’s lower right, at about the 5 o’clock position, taking Jupiter as the center of the clock, and 4 degrees away. (Remember the first three fingers, held together at arm’s length, span 5 degrees.) At magnitude 4.5, the comet might be visible by eye under dark skies, but not when seen against twilight skies. Try spotting it, appearing as a small, fuzzy ball, with binoculars or a telescope. Skies will be darker later, which will improve chances of spotting the comet, but looking through a thicker layer of atmosphere hinders views – but, overall, darker skies will likely triumph. At 8:45 P.M. Pons-Brooks will be 8 ½ degrees high and still at about the 5 o’clock position. The comet will be 6 degrees above the horizon at 9:00 P.M. and set at 9:37.

If you look at 8:15 Thursday night the Moon will be 13 degrees high and its visible face 14% in sunlit. Jupiter will be 17 degrees below Jupiter and a little to its right. Comet 12P/Pons-Brooks will be 3 ½ degrees below Jupiter and still at about the 5 o’clock position. By 8:45 the comet will be against darker skies and 8 degrees high. See if you can spot it will binoculars or a telescope.

Comet 12P/Pons-Brooks was first discovered by Jean-Louis Pons in 1812 at the Marseilles Observatory and seen again in 1883 by William Roberts Brooks. It is a periodic comet that orbits the Sun every 71 years. It is one of the brightest known periodic comets, but only becomes visible by eye under dark skies. If you read about the “Devil Comet,” that is its recent nickname, given when an outburst last year gave it an asymmetrical appearance, somewhat like having horns.