Saturday, April 23, 2011

Events for the Week 4/23 to 4/30

Saturday, April 23
Sitting in the northeast after dusk, the star Capella will be the brightest in the northeast, while Arcturus will be the brightest in the east. Both stars will have a magnitude of zero; the lower the number the better (a -2 star is brighter than a 0 star, etc.). Depending on your latitude, both stars will stand at exactly the same height above the horizon. Sunset occurs at 7:52 pm EDT for Washington DC.

Sunday, April 24

At 10:47 pm EDT the moon will be at last quarter, viewed from the constellation Capricornus. It will be in view (in Washington DC) at 1:47 am EDT (Monday), and sets later in the afternoon.

Monday, April 25

Viewing at astronomical twilight, (9:29 pm EDT in Washington DC) it is a good idea to view Sirius (in the southwest) and Orion (in the west). They sink lower each day; a great show of stellar procession. Stellar procession is the 'parade' of stars across the night sky.

Tuesday, April 26

Still viewing after astronomical twilight (tonight, at 9:31 EDT in Washington DC) Sirius is especially low, with Procyon high above it. Called the 'Little Dog Star,' Procyon will most always be high above Sirius but much dimmer, hence the name, the 'Little Dog Star.' If you keep on looking to the upper left of Procyon, Leo will be prominently featured in the constellation Leo. Hydra will also be represented: halfway between Procyon and Regulus. Hydra will be about the size of your thumb at arm's length.

Wednesday, April 27

The Big Dipper (Ursa Major) will be in view the end of this week after astronomical twilight. Depending on your latitude, it will be right overhead you along with the Little Dipper (Ursa Minor) horizontally extending to the right from Polaris. Sky and Telescope writes about the moon in location this week: "Before sunrise as April ends, the waning crescent Moon guides the way to four planets on the down-low. One should be easy to spot; the other three are a real challenge. (The visibility of the fainter objects in bright twilight is exaggerated here. These scenes are drawn for the middle of North America. European observers: move each Moon symbol a quarter of the way toward the one for the previous date)."
Thursday, April 28

On the morning of the 28th before sunrise (which is 6:15 am EDT in Washington DC), the waning crescent moon will be hanging low in the east. Four planets will be in the sky before the Sun pops over the horizon, Jupiter and Mars in conjunction. In the Urban Astronomer blog, this is what Paul Salazar writes about the conjunctions this week "Mars, Mercury, Jupiter and Venus are all occupying the same region of the sky from our Earth-bound point of view, and as these planets and our own planet are all in motion around the Sun, the pattern we see in the sky changes quite a bit from one night to the next." You can see the conjunctions in the picture above.

Friday, April 29

If you were not able to see the planets yesterday, try again today at sunrise (which is at 6:12 am EDT in Washington DC). The moon will be thinner and closer to Venus. An occultation of an asteroid and star (the moon has no roles tonight) will occur, as well. 7 Iris (10.3 magnitude asteroid--rather dim) will occult a star in the constellation Cancer. It will last up to thirteen seconds viewed from northern Washington State through Iowa and Illinois to Virginia and North Carolina. Approximately 04:17 UT (which is about 8:17 pm EDT).
 Visibility Map below:

Saturday, April 30

"The big Coma Berenices Star Cluster is often hidden by light pollution. But if you get to a dark sky, be sure to look for it — a very large, dim glow a third of the way from Denebola (the tail star of Leo) to the end of the Big Dipper's handle." ~Sky and telescope.

[~written by Matthew Winter~]

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