This Week's Sky at a Glance August 27 – September 4

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This Week's Sky at a Glance

Some daily events in the changing sky for August 27 – September 4

by Alan M. MacRobert

The Moon and Jupiter rise together on the evening of Friday the 27th. This is the view around 10 p.m.Sky & Telescope diagramFriday, August 27

  • Jupiter shines to the right of the waning gibbous Moon once they rise after dark, as shown here.
  • Low in the west-southwest in twilight, Venus forms the bottom of aflat, symmetrical triangle with much fainter Mars and Spica, which are alittle higher. Binoculars help.

    Saturday, August 28

  • The Venus-Spica-Mars triangle low in the west-southwest in twilight is distorting now, as Spica moves closer to Venus.

    Sunday, August 29

  • Jupiter's Great Red Spotshould transit the planet's central meridian within a few minutes of2:25 a.m. Monday morning EDT; 11:25 p.m. Sunday evening PDT. Mostmarkings on Jupiter, which tend toward red, tan, or brown, are a littlemore contrasty if you use a green or blue filter. With a small scope,use a lightly tinted filter. With a large scope, you have enoughlight-gathering aperture to use a darker, more strongly colored filter.

    Monday, August 30

  • If you're up before dawnTuesday morning, look for the Pleiades some 6° or 7° left of the waningMoon (for North America), as shown below.

    Early risers will catch the last-quarter Moon passing through Taurus high above early Orion.Sky & Telescope diagramTuesday, August 31
  • Use binoculars to look for1st-magnitude Spica just above Venus low in the fading sunset, as shownin This Week's Planet Roundup below. Note: Despite how the illustrationappears, Venus is 175 times brighter than Spica!

    Wednesday, September 1

  • Bright Venus andfaint Spica and Mars form an almost straight line a little less than 5°long, low in the west-southwest about a half hour after sunset as shownin This Week's Planet Roundup below.
  • Last-quarter Moon (exact at 1:22 p.m. EDT).

    Thursday, September 2

  • By the beginning ofSeptember the Great Square of Pegasus is looming well up in the eastafter dark, balanced on one corner: the sign of autumn to come. Thisyear bright Jupiter is the landmark; the Great Square is upper left ofit in early evening, as shown above.

    Friday, September 3

  • Mira, the prototype redlong-period variable star in Cetus, is in its way to a maximumpredicted for early October. It's probably not visible to the unaidedeye yet but should be easy in binoculars. You'll need to look for itafter midnight, however. See the chart in the September Sky & Telescope, page 58.

    Saturday, September 4

  • Low in thewest-southwest after sunset, Mars is now just 2° upper right of Spica,which is roughly 4° right of landmark Venus. Cloudy? Try again tomorrow.






    This Week's Planet Roundup

    Keepwatching the action around Venus after sunset. Note: the visibility offaint objects in bright twilight is exaggerated here.Sky & Telescope diagramMercury is hidden in the glare of the Sun.

    Venus, though bright at magnitude –4.4, is quite low in the west-southwest during twilight. It sets by dark.

    Mars, vastly dimmer at magnitude +1.5, is to Venus's right or upper right, as shown here. Look also for similar Spica passing by Venus this week, from upper left to right. They appear closest together on the 31st. Saturnhas moved far off to Venus's lower right and may be getting lost bynow. Bring binoculars for all three of these faint objects.

    Jupiter (magnitude –2.9, in Pisces) rises in twilight and is wellup in the east-southeast by late evening — the brightest starlike pointin the sky. It's highest in the south around 2 a.m. daylight savingtime.

    Jupiter's Great Red Spot is near System II longitude 150°. Assuming it stays there, here's a list to print out of all the Great Red Spot's predicted transit times for the rest of 2010.

    The changes continue...Sky & Telescope diagramUranus (magnitude 5.8, in Pisces) is not quite 2° west ofJupiter. In a telescope Uranus is only 3.7 arcseconds wide, compared toJupiter's unusually wide 49″.

    Neptune (magnitude 7.8, at the Aquarius-Capricornus border) is up high by mid-evening. See our finder charts for Uranus and Neptune in 2010, also in the September Sky & Telescope, page 56. What colors do Uranus and Neptune seem to show, if any?

    Pluto (magnitude 14, in northwestern Sagittarius) is highest inthe south right at the end of dusk, when there's no Moon. See our Plutofinder charts in the July Sky & Telescope, page 60.

    All descriptions that relate to your horizon or zenith — includingthe words up, down, right, and left — are written for the world'smid-northern latitudes. Descriptions that also depend on longitude(mainly Moon positions) are for North America. Eastern Daylight Time(EDT) equals Universal Time (also known as UT, UTC, or GMT) minus 4hours.

    To be sure to get the current Sky at a Glance, bookmark this URL:
    http://SkyandTelescope.com/observing/ataglance?1=1

    If pictures fail to load, refresh the page. If theystill fail to load, change the 1 at the end of the URL to any othercharacter and try again.


    • This Week's Sky at a Glance August 27 – September 4 This Week's Sky at a Glance July 30 July 30 – August 8 This Week's Sky at a Glance for August 20 – 28 This Week's Sky at a Glance for September 9 – 18 This Week's Sky at a Glance for September 17 – 25. This Week's Sky at a Glance for September 24 – October 2 This Week's Sky at a Glance for November 26 – December 4 SkyandTelescope.com - This Week's Sky at a Glance This Week's Sky at a Glance July 16 – 24 This Week's Sky at a Glance July 23 – 31 This Week's Sky at a Glance for October 1 – 9 This Week's Sky at a Glance for October 8 – 16 This Week's Sky at a Glance for October 15 – 23 This Week's Sky at a Glance for October 22 – 30. This Week's Sky at a Glance for October 29 – November 6 This Week's Sky at a Glance for November 5 – 13 This Week's Sky at a Glance for November 12 – 20 This Week's Sky at a Glance for December 17 – 25 September Week 4 - Yet More DISTANCE EDUCATION AT A GLANCE DISTANCE EDUCATION AT A GLANCE Men in a Buying Mood This Valentine‘s Day Glance at politics in Latin America Third Time's a Flash at Annual Memory Summit