观赏鱼白点病治疗:This Week's Sky at a Glance April 1 – 9

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This Week's Sky at a Glance

Some daily events in the changing sky for April 1 – 9

by Alan M. MacRobert

Orion, with belt horizontal, was declining in the southwest when S&T's Tony Flanders took this 15-second exposure with a Canon A80 pocket digital camera.S&T: Tony FlandersFriday, April 1

  • Early spring is when Orion tiltsdownward in the southwest after dark, with his three-star belthorizontal as seen from north temperate latitudes. Orion's Belt pointsleft toward bright Sirius (out of the frame here), and to the right moreor less toward orange Aldebaran (also outside the frame). Right ofAldebaran are the Pleiades.

    Saturday, April 2

  • Sirius, the Dog Star, isthe brightest star shining in the south-southwest after dusk. At adistance of only 8.6 light-years, it's the nearest thing outside oursolar system that's visible to the naked eye from Earth's mid-northernlatitudes. Look high above Sirius for Procyon, the Little Dog Star, notmuch farther away at 11 light-years.

    Sunday, April 3

  • Saturn is at oppositiontonight, opposite the Sun in Earth's sky. Look for the brightening ofSaturn's rings this week due to the Seeliger effect, described in "ThisWeek's Planet Roundup" below.
  • New Moon (exact at 10:32 a.m. EDT).

    Monday, April 4

  • Look very high in thenortheast after dark this week for the Big Dipper starting to tip overto the left, after standing straight up on its handle when winter wasnearing its end.

    Tuesday, April 5

  • A small telescope willalways show Titan, Saturn's largest moon. Tonight Titan is at greatestelongation, four ring-lengths to Saturn's west. A 6-inch telescope willbegin to show the orange color of its smoggy atmosphere. Saturn's othermajor moons appear much closer to the planet tonight.

    Watchthe waxing crescent Moon ascend from night to night in the twilighttoward the Pleiades and Hyades. (These scenes are drawn for the middleof North America. European observers: move each Moon symbol a quarter ofthe way toward the one for the previous date. For clarity, the Moon isshown three times actual size.)Sky & Telescope diagramWednesday, April 6

  • As twilight fades, look for the Pleiades above the Moon as shown at right (for North America).

    Thursday, April 7

  • Look for orange Aldebaran to the left of the Moon, and the Pleiades to the Moon's lower right, as shown here.
  • This evening the Moon's earthlit dark limb will beautifully occult(cover) Kappa and/or Upsilon Tauri for observers in much of westernNorth America. Both stars are magnitude 4.3. Kappa also has a5.3-magnitude companion 0.1° to its south. See prediction maps and localtimetables for Kappa and for Upsilon.

    Friday, April 8

  • Arcturus, the "SpringStar," is the brightest point high in the east these evenings. Wait uptill after about 10 or 10:30 and you can get an early sighting of Vega,the equally bright "Summer Star," rising low in the northeast.

    Saturday, April 9

  • The Moon this evening is avery thick crescent less than two days from first quarter. If your skyis really clear after dark, binoculars will show the star cluster M35 inthe feet of Gemini roughly 2° to the Moon's upper right (for NorthAmerica). It's a largish, dim, hazy glow in binoculars, and a city ofindividual stars in a telescope.

    • This Week's Sky at a Glance April 1 – 9 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 15 – 23 This Week's Sky at a Glance for April 22 –30 This Week's Sky at a Glance - SkyandTelescope.com 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 February 25 – March 5. 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