谁有成人色情免费网站:This Week's Sky at a Glance for April 15 – 23

来源：百度文库 编辑：九乡新闻网 时间：2024/04/27 03:24:46

This Week's Sky at a Glance

Some daily events in the changing sky for April 15 – 23

by Alan M. MacRobert

Alert: T Pyxidis has finally blown up! The recurrent nova T Pyxidis, which had its last outburst in December 1966 and has been very overdue for its next, has shot up from magnitude 15.4 to at least 8.5. In 1966–67 it reached 6.5.

Here's a Blink animation showing before and after, courtesy Ernesto Guido and Giovanni Sostero in Italy. South is up.

It's in the dim constellation Pyxis east of Puppis and Canis Major.Pyxis is currently fairly high in the south-southwest right after dark,in good view for observers at north temperate latitudes and pointssouth. The star is at declination –32°.

Here are finder and comparison-star charts from Sky & Telescope, and larger-scale comparison-star charts 15° wide, 5° wide, and2° wide courtesy of the American Association of Variable Star Observers (AAVSO).On all charts north is up and east is to the left. The numbers next tostars are comparison-star magnitudes to the nearest tenth with thedeconal points omitted.

More information.

Old AAVSO article.

As the Moon waxes to full, it teams up with Saturn in the evening sky.Sky & Telescope diagramFriday, April 15

  • Look high in the northeast afterdark for the Big Dipper. It's tilting rightward on its handle. Youprobably know that the two stars forming the top end of the Dipper'sbowl are the Pointers, pointing lower left toward Polaris. Less wellknown is that if you follow the Pointers backward in the oppositedirection (by a greater distance), you land in Leo.

    Saturday, April 16

  • Upper left of the nearlyfull Moon this evening are Saturn and fainter Gamma Virginis (Porrima).They're currently only 2½° apart, and they'll close up further in thecoming weeks. Also in the Moon's neighborhood are Spica and Corvus, asshown here.

    Sunday, April 17

  • Full Moon (exact at 10:44p.m. EDT). Standing in a nearly vertical row above the Moon at dusk areSpica, Saturn, and Gamma Virginis, as shown here. As the night goes on,the whole arrangement rises higher and tips to the right.

    Monday, April 18

  • Vega, the "Summer Star,"is now rising in the northeast right around the end of twilight(depending on your latitude). Later in the night as Vega rises higher,look for its dim little constellation Lyra dangling from it toward thelower right.

    Planets shortly before sunrise. Their visibility in bright dawn is exaggerated here.Sky & Telescope diagram

  • A dawn challenge! On Tuesday morning, about 15 minutes before your local sunrise time,use binoculars or a wide-field telescope to look 15° lower left ofVenus for faint Mars and even fainter Mercury in conjunction, as shownhere. Not an easy sighting!

    Tuesday, April 19

  • Have you been keeping aneye on bright Sirius in the southwest, and Orion in the west, around theend of twilight? They're still in view but sinking lower daily. Howmuch longer can you keep them in view?

    Wednesday, April 20

  • Sirius, the Dog Star,shines brightly low in the southwest right after dusk. High above it isProcyon, the Little Dog Star. Very far to Procyon's upper left isRegulus in Leo. Nearly halfway from Procyon to Regulus, look for a dimbut distinctive asterism: the head of Hydra, the Sea Serpent. It's aboutthe size of the end of your thumb at arm's length.

    Thursday, April 21

  • A small telescope willalways show Titan, Saturn's largest moon. This evening Titan is fourring-lengths to Saturn's west. Look roughly one ring-length to Saturn'snorthwest for dimmer Rhea and Dione quite close together.

    Friday, April 22

  • The Lyrid meteor showershould peak late tonight, but it's usually quite weak. The best chanceto see an occasional Lyrid will be around midnight daylight-saving time,when Lyra is up fairly high but the Moon hasn't yet risen.
  • Just south of Regulus is the dim but galaxy-ridden constellationSextans, the Sextant. Dig up some of its far sights using Sue French'sDeep-Sky Wonders column, chart, and images in the April Sky & Telescope, page 58.

    Saturday, April 23

  • Capella is the brighteststar shining in the northwest right after dusk. Arcturus is thebrightest shining in the east. Both are magnitude zero — and this week,both stand at exactly the same height above your horizon aroundnightfall (depending on your latitude). How accurately can you time thisevent for your location?



    • This Week's Sky at a Glance for April 15 – 23 This Week's Sky at a Glance for March 25 – April 2. This Week's Sky at a Glance for April 8 – 16 This Week's Sky at a Glance for April 22 –30 This Week's Sky at a Glance April 1 – 9 This Week's Sky at a Glance for December 31 – January 8 This Week's Sky at a Glance for January 7 – 15. This Week's Sky at a Glance for January 14 – 22 This Week's Sky at a Glance for January 21 – 29 This Week's Sky at a Glance for January 28 – February 5 This Week's Sky at a Glance for February 4 – 12 This Week's Sky at a Glance for February 18 – 26. This Week's Sky at a Glance for March 4 – 12 This Week's Sky at a Glance for March 18 – 26 This Week's Sky at a Glance for May 20 – 28 This Week's Sky at a Glance for May 27 – June 4. This Week's Sky at a Glance for June 3 – 6 This Week's Sky at a Glance for June 17 – 25 This Week's Sky at a Glance for July 29 – August 6 This Week's Sky at a Glance for September 8 – 17 This Week's Sky at a Glance for September 16 – 24 This Week's Sky at a Glance for June 24 - July 2 This Week's Sky at a Glance - SkyandTelescope.com This Week's Sky at a Glance February 25 – March 5.