Tonight, you’ll find the 9th-magnitude space rock 2.2° north of Hydor (Lambda Aquarii), which shines at magnitude 3.7. Over in Aquarius the Water-bearer, asteroid 2 Pallas is slowly sliding southwest, diving south through the ecliptic, the plane of our solar system. Astronomy columnist Phil Harrington offers some tips and tricks for estimating this wonderful variable star’s brightness in his October 2020 Binocular Universe column, “The wonderful variable star.” Once you’ve found it, see if you can determine Mira’s brightness by comparing it to the stars around it. Even now, it’s still well within the range of naked-eye visibility. That’s a difference of some 1,600x in brightness! It also means Mira is only sometimes visible with the naked eye, while at other times it fades from view without the aid of binoculars.įortunately for us, Mira was last at its peak brightness in late August by early September, it was magnitude 3. Over the course of its 332-day period, Mira undergoes a vast change in visibility, growing as bright as 2nd magnitude and as faint as 10th magnitude. It is the archetypical Mira variable, which is a type of variable star that changes brightness over about a year. This famous star has a name that translates to wonderful, so named by Polish astronomer Johannes Hevelius in the mid-1600s. And about the same distance to Delta’s right (southwest) is Mira. To its left (northeast) is bright Menkar, the Whale’s alpha star. Wait a few hours for it to get a bit higher, then look again for Delta Ceti. If you looked for Harmonia last night, you already know that Cetus is rising in the east as the Sun sets in the west.
The American Association of Variable Star Observers’ featured variable of the month for October is Mira, also cataloged as Omicron (ο) Ceti. local time from the same location.Ī new month means it’s time to check out a new variable star. The Moon’s illumination is given at 12 P.M. *Times for sunrise, sunset, moonrise, and moonset are given in local time from 40° N 90° W. This face-on spiral has an actively feeding black hole at its center, earning it a classification as a Seyfert galaxy. Slightly brighter and also worth finding once Cetus has fully risen is the spiral galaxy M77, which shines at magnitude 8.9 a little less than 1° east-southeast of 4th-magnitude Delta (δ) Ceti. The longer you wait, the higher Harmonia will rise in the sky and the easier it will be to spot its magnitude 9.5 glow in binoculars or a small telescope. You can also use 5th-magnitude 20 Ceti as a jumping-off point: Harmonia is about 3.6° southwest of this luminary, roughly level with it in altitude as they rise. Harmonia sits 7.7° east-northeast of this star. You can find it in Cetus the Whale tonight, visible all evening and into the early morning hours of the 2nd.Īn hour after sunset, look east, where magnitude 3.6 Iota (ι) Ceti is rising, already more than 6° high. The 66-mile-wide (107 kilometers) asteroid 40 Harmonia reaches opposition this afternoon at 3 P.M.
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