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GREGORIAN CALENDAR.

calendar notes

Pallas brightens. During the first three months of 2000, asteroid 2 Pallas will be easy to find in binoculars as it wends its way from Puppis through Monoceros toward Canis Minor (see the chart on page 96). After opposition to the Sun

on January 27th the minor planet peaks at magnitude 7.4 around February 5th, the day it passes 1.33 astronomical units (just less than 200 million kilometers) from Earth. According to Belgian astronomer Jean Meeus, it won't come this close again until February 2014 (at 1.23 a.u.). On the evening of February 3rd Pallas can be found just southwest of the open cluster M93. On February 27-28 it goes through the outer fringe of an even brighter cluster, M47.

Partial eclipse of the Sun. The first of four partial solar eclipses in 2000 occurs on February 5th. However, this event is not visible from any sizable land area except Antarctica. There, up to 58 percent of the Sun's diameter will be covered by the Moon's disk.

Jupiter's Red Spot. Here are the Universal dates and times when the center of the Great Red Spot should cross Jupiter's central meridian, the imaginary line down the center of the planet's disk from pole to pole. The spot has been pale orange-tan in recent years. It appears slightly more distinct when Jupiter is viewed through a light green or blue filter.

February 1, 9:46, 19:42; 2, 5:38, 15:34; 3, 1:30, 11:26, 21:21; 4, 7:17, 17:13; 5, 3:09, 13:05, 23:01; 6, 8:56, 18:52; 7, 4:48, 14:44; 8, 0:40, 10:36, 20:31; 9, 6:27, 16:23; 10, 2:19, 12:15, 22:11; 11, 8:06, 18:02; 12, 3:58, 13:54, 23:50; 13, 9:46, 19:41; 14, 5:37, 15:33; 15, 1:29, 11:25, 21:21; 16, 7:16, 17:12; 17, 3:08, 13:04, 23:00; 18, 8:56, 18:51; 19, 4:47, 14:43; 20, 0:39, 10:35, 20:31; 21, 6:26, 16:22; 22, 2:18, 12:14, 22:10; 23, 8:06, 18:02; 24, 3:57, 13:53, 23:49; 25, 9:45, 19:41; 26, 5:37, 15:33; 27, 1:28, 11:24, 21:20; 28, 7:16, 17:12; 29, 3:08, 13:03, 22:59.

These predictions assume the Red Spot is at Jovian System II longitude 66U, the most recent value provided by John W. McAnally of the Association of Lunar and Planetary Observers (www.lpl.arizona.edu/alpo).

Variable-star maxima. February 3, R Ophiuchi, 170215, 7.6; 9, R Ursae Majoris, 103769, 7.5; 10, U Octantis, 131283, 7.9; 18, W Lyrae, 181136, 7.9 (see chart, May 1990, page 524); 23, T Pavonis, 193972, 8.0.

The data above are, in order: the day of the month near which the star should be at maximum brightness; the star's name; its designation number, which gives rough equinox-1900.0 right ascension (first four digits) and declination (boldface if southern); and the star's typical visual magnitude at peak brightness. The actual maximum may be brighter or fainter and many days early or late. All predictions are by Janet Mattei using recent data of the American Association of Variable Star Observers, 25 Birch St., Cambridge, MA 02138 (www.aavso.org). Stars are listed if magnitude 8.0 or brighter at average maximum.

Minima of Algol. February 2, 8:43; 5, 5:32; 8, 2:21; 10, 23:11; 13, 20:00; 16, 16:49; 19, 13:39; 22, 10:28; 25, 7:17; 28, 4:07.

These are the dates and times, in Universal Time, when the eclipsing variable star Algol (b Persei) should be at its dimmest, magnitude 3.4 instead of its usual 2.1. It is nearly this faint for two hours, and it takes several hours to fade and brighten. These geocentric predictions are from the heliocentric elements Min. = J.D. 2,441,598.608 + 2d.867315E, based on 95 timings from 1972 to 1990 analyzed by John Isles.

Universal Time (UT or UTC) is used worldwide by astronomers and others to avoid confusion between time zones. It is expressed in the 24-hour system, whereby 1:00 p.m. is called 13:00, 2:00 p.m. is 14:00, and so on.

To convert a UT time and date to a standard time and date in North America, subtract the following hours: to get Eastern Standard Time, 5; CST, 6; MST, 7; PST, 8; Alaska, 9; or Hawaii, 10. To obtain daylight saving time ("summer time"), subtract one hour less than these values. If you get a negative number of hours, add 24; in this case the result is on the date before the UT date given.

For example, 6:45 UT February 9th is 1:45 a.m. on the 9th EST and 10:45 p.m. on the 8th PST.

AstroAlert News Service. Amateurs everywhere are invited to join Sky & Telescope's e-mail network for quick notification of fleeting astronomical events. For example, time-critical observations are needed by professional astronomers if and when the next supernova goes off in our Milky Way or the Local Group. A bright comet may suddenly appear, or a solar flare may mean that an auroral display is imminent.

To begin receiving AstroAlert messages, visit www.skypub.com/news/astroalert.html and follow the instructions. This service is further described in the August 1999 issue, page 34.
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Title Annotation:Pallas, Jupiter, Minima of Algol, and Variable-Star Maxima observations
Publication:Sky & Telescope
Article Type:Brief Article
Date:Feb 1, 2000
Words:928
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