Skywatch Line for Monday and Tuesday, 25th and 26th, 2020

This is the Skywatch Line for Monday and Tuesday, 25th and 26th, written by Joe Slomka.

The Sun sets at 8:21 PM; night falls at 10:28. Dawn begins at 3:16 AM and ends with the Sun rising at 5:23.

The Moon occupies Gemini on both nights. Monday’s 3-day-old Moon is moderately low in the western sky, shines with minus 9th magnitude, 11 percent illuminated and sets at 11:22 PM. Tuesday’s Moon is a bit higher, larger, 18% lit and sets at 12:12 AM on Wednesday. Note that on Monday, the Moon rested between Gemini’s legs and on Tuesday will be 6° left of the bright star Pollux.

Venus and Mercury are bright evening planets, sharing Taurus. Venus rose first, and by Civil Twilight, is a very thin crescent, 4° high, minus 4th magnitude and sets at 9:31 PM. Mercury, is dimmer with minus 0 magnitude, much smaller, but 7° higher than Venus. Observers will see that Venus becomes progressively lower, in preparation for next week’s inferior conjunction with the Sun, while Mercury is higher.

The pre-sunrise south-eastern sky is full of interesting objects. Dwarf Planet Pluto rises first in Sagittarius at 11:53 PM, Monday; it glows with 14th magnitude and appears a fraction of an arc-second. It is situated only 2° from giant Jupiter, which rises 4 minutes later, is much brighter with minus 2nd magnitude and a huge 44 arc-seconds in size. Saturn, in Capricornus, rises Tuesday at 12:16 AM, shining with zero magnitude and 17 arc-seconds. Pluto, Jupiter and Saturn are all about 23° in altitude. Mars, in Aquarius, continues its eastward plunge, rising at 2:04 AM, also shining at 0 magnitude, 9 arc-seconds in size, 85% lit, and 13° high. Neptune, also in Aquarius, is only 12° east of Mars; it rises at 2:26 AM, shines with 8th magnitude and is a moderate 2 arc-seconds in size. Finally, Dwarf Planet Ceres, also in Aquarius, lies 7° east of Mars, shines with 9th magnitude and is 13° high by Dawn. Uranus rises in Aries at 4:13 AM, shines with 6th magnitude, and 3 arc-seconds in diameter. Pluto, Ceres, Uranus and Neptune may require sky charts to locate them, available from various astronomical media.

Comet Swan (C/2020 F8) has the unusual distinction of appearing very low in both the Twilight and Dawn skies in the constellation Perseus. On Monday’s Civil Twilight, at about 9 PM, it is found west of the star 53 Per and about 23° east of Venus. A slightly better view is available on Tuesday Civil Dawn, when it lies about 7° high in the north-eastern sky in almost the same position in Perseus and not far from Auriga’s bright star Capella.

If you follow the “arc” of the Big Dipper’s handle, you come to the bright star Arcturus. Arcturus is the sixth brightest star and one of the nearest, only 37 light-years away. Arcturus is a giant, about 25 times larger than our Sun. Astronomers have known, for some time, that Arcturus is rapidly approaching our solar system. Several thousand years from now, Arcturus will brighten, loom larger, speed past us and then disappear into space. A new theory thinks that Arcturus, and other stars, are actually part of a small galaxy that our own Milky Way gobbled up in the recent past.

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