Wednesday, February 29, 2012

Bright Jupiter, Brilliant Venus, and Elusive Mercury

Every night over the next week, Mercury shines very low in the west at 7:00 p.m. Venus and Jupiter lie much higher in the sky and are much brighter. Do not expect little Mercury to stand out noticeably in the bright twilight. Look carefully for it about 15 degrees above the horizon. How high is 15 degrees? Outstretch your hand on your fully extended arm. The angular distance between the tips of the thumb and little finger is 20 degrees. So, 15 degrees is 3/4 that distance.

In the image, Mercury lies almost hugging the mountain ridge line. Definitely a challenge!

A pair of binoculars will aid in finding Mercury. Good hunting!

Such is our view from Earth...

Tuesday, February 28, 2012

Spy Mercury in our western evening sky

The closest planet to the sun is also the most difficult of the "bright planets" to spot in our evening or morning sky. Over the next couple of weeks, little Mercury can be seen if it is clear and if one knows when and where to look.

Unlike the other bright planets — Venus, Jupiter, Mars, and Saturn — Mercury is easily lost in the twilight. Tonight it sits just above the western horizon at about 7 p.m. How far above? Extend our hand on your outstretched arm. Mercury's distance will be about 1/4 the distance between the tips of your thumb and little finger.

Mercury will appear as a "starlike" object. Over the next five nights or so, it will rise slightly higher before its luminosity begins to drop. If you see it tonight, you are looking 100 million miles to the smallest planet which spans about one-third of the Earth's diameter.

Such is our view from Earth...

Thursday, February 23, 2012

The crescent moon gives a magical cast in our western sky

Look low in the west on Saturday sixty minutes after sunset for the thin crescent moon glowing next to brilliant Venus. The back reflected sunlight off the Earth, known as Earthshine, will light the night regions of the moon. This will give the moon an eerie glowing effect. Binoculars enhance the scene making it appear almost magical.

While looking at both bodies, consider that Venus lies 362 times farther than the moon. It also gives a more intense light than the moon because its atmospheric cloud tops reflect much more light than the asphalt shaded lunar surface.

Look in the west on Sunday sixty minutes after sunset for the crescent moon glowing next to bright Jupiter. As on the previous night, the moon will show Earthshine. Jupiter lies five times farther than Venus and over 2000 times farther than the moon.

Such is our view from Earth…

Tuesday, February 21, 2012

See Orion's Star Factory

Look in the south at 9 p.m. for the constellation Orion, the Hunter. It is comprised primarily of easily seen stars tracing a somewhat boxy figure. Betelgeuse shines on its upper left corner and Rigel at its lower left corner. Half way between them are three stars of equal brightness spaced equally apart. These are Orion's belt stars. About half way between the left belt star and Rigel lies a fuzzy star. This is no single star, but a star factory – The 1300 light-year distant Orion Nebula. Aim binoculars at it for real celestial treat.

Easily seen is its wispy, or nebulous, nature. Its bright center fans out and slowly dissipates into nothingness. Many true stars also appear in the region.

Binoculars are generally 10 power. The drawing is done at 20 power.

Such is our view from Earth...

Friday, February 10, 2012

Venus drifts next to Uranus

Last night was clear in this part of Virginia, allowing for viewing of Venus next to Uranus. The picture was taken from downtown Roanoke which explains the yellow sky glow. Dim Uranus is the object immediately to the left of bright Venus. The other objects are stars of various brightnesses. Their short streaks are due to the Earth's rotation during the 15 second exposure. Yes, Uranus is very dim, but considering that the image was taken from a well-lit downtown area, it is remarkable that it could be seen at all.

Why not try imaging the night sky with your digital camera using its manual settings? Image what could be recorded from a dark location!

Such is our view from Earth...

Thursday, February 9, 2012

Venus and Uranus — Tonight!

Tonight is your chance to see distant Uranus, the most difficult to spot "naked eye" planet.

Tonight is the conjunction, i.e., close approach with each other, of Venus and Uranus. Look to the west at 7:30 p.m. at blazing Venus while using binoculars. Just to the left of Venus will be a dim starlike object. That will be Uranus.

Why not photograph both objects when they are so close to each other? If you have a digital camera with manual control capability:
• place it on a tripod,
• if it has a variable ASA setting, set that at the maximum value,
• set the focus at infinity,
• open the f stop as wide as it will go,
• adjust the shutter speed to 8 or 15 seconds,
• and zoom on Venus.

Take a couple of shots and download them to your computer's photo program. Uranus likely will have been captured along with the surrounding star field. Astronomy without a telescope!

Such is our view from Earth...

Wednesday, February 8, 2012

Galaxy Formation Lecture at Roanoke College, 2/12

SUN, 12 FEB, 5.30-6.30pm, TREXLER HALL 372, Roanoke College, Salem, VA

Dr. Elizabeth McGrath
Lick Observatory, Univ. of California- Santa Cruz

Title: Exploring the Formation of the Largest Galaxies in the Universe

Abstract: New observations from some of the most powerful telescopes in
the world, including the Hubble Space Telescope, are changing the way we
think about massive galaxy formation and evolution. I will describe how
these observations allow us to extrapolate backwards in time in order to
infer the formation histories of galaxies more massive than our own
Milky Way, and discuss the implications of these results on our current
theoretical understanding of galaxy formation. Finally, I will conclude
with a few exciting prospects for future investigations that will be
made possible both with ongoing surveys and future technological

Such is our view from Earth...

Monday, February 6, 2012

Spy mysterious Uranus

The seventh planet of the solar system, Uranus, never appears brightly in our sky. In fact, it always hovers on the edge of visibility, making it difficult to spot with the unaided eye. On Thursday February 9, it can be found with relative ease, though.

Venus shines brilliantly in the west shortly after sunset. From our point of view, it appears to move right next to faint Uranus on the 9th. Look with binoculars at 7:30 p.m. at Venus. Uranus is the dim starlike object immediately to its left. You are looking at Venus lying 98 million miles from our little blue world and Uranus lurking 1934 million (=1.934 billion) miles away.

Does the glare from Venus blot out the much, much dimmer Uranus?

Such is our view from Earth...

Sunday, February 5, 2012

Discover February's Celestial Treasures

The month of February brings the winter Milky Way overhead and the big, bright constellation Orion high in the south a couple of hours after sunset. Both brilliant Venus and bright Jupiter are hard to miss in the west, while red Mars peeks above the eastern horizon before 9 p.m.

Binocular users will be rewarded with the Orion Nebula, or M42, faintly glowing to the upper left of the bright star Rigel. Scanning the constellation of Auriga, nearly overhead, will reveal several dim star clusters imbedded in the overall glow of the Milky Way.

Such is our view from Earth...