If you're new at this, start with brighter, easier constellations and save the shy Giraffe until you get good at it. Unless you have a really dark sky, you'll need binoculars to work out its loose, faint, nondescript pattern using the constellation chart in the center of Sky & Telescope - a challenge project that will build your skills for correctly relating what you see in binoculars to what you see, much smaller, on a sky map. ■ High in the northern sky these evenings, in the seemingly empty wastes between Capella overhead and Polaris due north, sprawls big, dim Camelopardalis, the Giraffe - perhaps the biggest often-visible constellation you don't know. It and the rest are about 560 light-years away. ![]() Some of them form a distinctive curving arc focused on Alpha Persei.Īlpha Per, a white supergiant, is a true member of the group and by far its brightest light. At least a dozen are 6th magnitude or brighter. It lies on the lower-right edge of the Alpha Persei Cluster: a large, elongated, very loose scatter of fainter stars about the size of your thumbtip at arm's length. The brightest star between Cassiopeia and the zenith right after dark, as seen from the world's mid-northern latitudes, is Alpha Persei (Mirfak), magnitude 1.8. ■ Right after nightfall this week, the W of Cassiopeia shines high in the northwest standing almost on end. The eerie waning gibbous Moon, with 1st-magnitude Spica, clears the east-southeast horizon around 11 p.m. ■ The waning gibbous Moon rises late Friday night, with 1st-magnitude Spica about 3° to its right or lower right as shown below. The whole array will seem to rotate clockwise as it moves lower toward the west. The orientation of this scene changes as the night grows late. This is the naked-eye setting for faint Comet ZTF as it passes Mars on Friday the 10th and Saturday the 11th see the text. Tomorrow evening, Saturday, the comet will be 1.8° below Mars. The comet is 1.6° upper left of Mars, at the top of the "s" in "Mars" in the diagram below (for evening in North America). Right after the end of twilight, face south and look very high, almost overhead. ![]() The Moon doesn't rise until about 10 or 11 p.m. Although the comet has dimmed to about magnitude 6.3, binoculars should still show it if you have a good dark sky. ■ Comet ZTF passes Mars this evening and tomorrow evening. Sirius is the cleaver's top back corner, its blade faces right, and its short handle is down below pointing lower left. Sirius is on his chest, to the right or lower right of his faint triangular head.īut through the light pollution under which most of us live, only his five brightest stars are easily visible. He's currently standing on his hind legs. In a dark sky with lots of stars visible, the constellation's points can be connected to form a convincing Big Dog profile. ■ Sirius the Dog Star blazes in the southeast after dinnertime, below Orion. It should be down to 7.5 by February 17th. And of course the comet's light is much more spread out ("diffuse"). By then it will probably be about mag 6.4, which is some 300 times fainter than Mars. On the evenings of February 10th and 11th the comet will be less than 2° from bright Mars. ![]() When the comet becomes too faint for that chart to suffice, use the more detailed one in the February Sky & Telescope, page 48 (where the dates are for 0:00 UT subtract one day from those to get the North American civil date). (On that chart, the comet symbols are labeled with the dates for evenings in North America, not the UT dates.) Bob King's new article Understanding the Tails of Comet ZTF has a finder chart to use in February. The comet is heading south after its swing past the Little Dipper in late January. Don't confuse long-exposure, stacked and processed images of a dim, diffuse object like this with its appearance to the eye, even in the same telescope! Note the narrow, straight ion tail and the broad, curved dust tail. Comet ZTF E3, imaged on January 21st by Pepe Chambó of Valencia, Spain, using an 8-inch short-focus reflector. That evening, using 10 x 50 binoculars under a mediocre suburban sky, I could just detect it near Iota Aurigae as a vague, diffuse enhancement of the sky background. As of February 9th it was down to about 6.1. It peaked in brightness on February 1st at about magnitude 5.0. The comet is crossing Auriga and Taurus on its way toward Orion's shield. On the other hand, it's now conveniently placed high overhead in early evening in a moonless sky the waning Moon doesn't rise until late. Comet ZTF is fading and receding into the distance.
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