Report for 2001-05-11
Welcome to the Utah Skies Report.
Brought to you from beautiful Park City, "View-tah".
Weekend Viewing Conditions Outlook
Did you see the beautiful full moon this past weekend?
Wow! It was so big and bright. It actually cast some intense shadows.
| Sunrise: 6:14 am | Sunset: 8:33 pm |
| Astronomical Twilight Ends: 4:24 am | Astronomical Twilight Begins: 10:23 pm |
| Moonrise: none | Moonset: 9:23am |
Planetary Report
| In our planetary report today we'll focus
on a new arrival on the scene. Fleet footed Mercury is beginning to rise in
the western sky shortly after sundown. To spot Mercury though, you'll need a
really low western horizon. Probably your best bet would be on the east bench
down in Salt Lake. Mercury is the closest planet to the sun. Because of this, it has the smallest orbit of any of the planets. Mercury moves quickly from the nighttime sky to the morning sky and back, typically spending no more than a few weeks in either. Mercury is currently moving away from the sun and will be at its greatest distance (referred to as greatest elongation) on May 24th. So, you've got about 3 weeks to catch a glimpse. After that, Mercury will move too close to the sun to be seen. Have you ever seen the planet Mercury? Because Mercury orbits so close to the Sun, it is never seen far from the Sun, and so is only visible near sunrise or sunset. If trailing the Sun, Mercury will be visible for several minutes before it follows the Sun behind the Earth. If leading the Sun, Mercury will be visible for only several minutes before the Sun rises and hides it with increasing glare. This image, taken by Juan Carlos Cansado in Spain, shows the motion of Mercury in the evening sky in the middle of April, 2000. |
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Mercury has a harsh environment. Being the closest planet to the sun, Mercury has had its atmosphere blasted away by the solar wind. Temperature variations on Mercury are the most extreme in the solar system ranging from 90 K to 700 K. The temperature on Venus is slightly hotter but very stable. Mercury is in many ways similar to the Moon: its surface is heavily cratered and very old. Mercury has been visited by only one spacecraft, Mariner 10. It flew by three times in 1974 and 1975. Only 45% of the surface was mapped (and, unfortunately, it is too close to the Sun to be safely imaged by HST). |
Before we move on, let's also briefly touch on Mars. Mars continues to grow almost daily. It's currently at 16" on its way to
over 21'' this summer. Mars is growing approximately 1" each week. Mars will be
rising in the southeast at about 10:30pm and will be at it's highest point in
the sky (referred to as the zenith) by 3:00am. Mars is the bright reddish object about 30 degrees above
the horizon in the constellation Sagittarius. Mars has more than doubled in
brightness since we first mentioned it a few weeks ago and will soon be even
brighter than Jupiter. Now would be an ideal time to check it out. Hint..
Hint... Hint..
Telescope Talk
| Let's take a brief detour and discuss astronomy software. There are many choices out there. One of my personal favorites is a product called Red Shift. I have used version 3.0 for about a year and a half. (Red Shift 4.0 was recently released). It does most of the things I expect from an astronomy package. It will show you a pretty realistic view of what's up in the sky at any time in any direction. You can customize it for your location and tell it what objects to show. It contains a wealth of information about all the objects in its database. Information such as type, size, distance, brightness, etc. I use it often to plan my viewing sessions and also while researching this newsletter. If you have yet to purchase an astronomy software title, Red Shift is definitely one to consider. |
Constellation Report
Our Constellation report is an easy way for people to become familiar
with the nighttime sky. We’ll discuss myths associated with the various
constellations as well as describing the numerous deep sky objects residing
in the area. No equipment is required to view the constellations, though
a star chart can be quite helpful. This ease of observing makes constellations
a natural place to begin your journey to the stars. This weekend we’ll focus on the constellation
Virgo.
| Virgo, the Virgin is one of three illustrious women to be found in the star-speckled sky. The other two, Cassiopeia and Andromeda are from the same family. The figure of Virgo can be difficult to make out in the starry sky, with most of her stars being rather dim. You can, however, be sure you have found her by locating the sparkling gem which she holds, the bright star Spica. Most people do it this way. First locate the Big Dipper in Ursa Major, currently high overhead in the evening sky. Follow the curve of the handle of the dipper and continue it down to the southeast until you come to the brilliant star Arcturus, in the constellation Bootes. Continue that same arc to the next bright star, lower and farther to the south. This is Spica. Arcturus has a slightly orange color and Spica is very white. Let me repeat the method of finding it: "follow the arc to Arcturus, then speed on to Spica." This little statement, known well to those who love the sky, might help you connect and remember these stars. |  |
Deep Sky Report
The focus of our efforts this week will be the galaxies of Virgo.
| First off, lets visit one of the more
well known galaxies in the area, M104 The Sombrero Galaxy (mag 8.0). This
edge-on spiral is located at the base of a perfect right triangle
comprised of Spica (alpha) and Porrima (gamma) Virgo, The Sombrero Galaxy
is a spectacular object when viewed through larger telescopes. It's dust
is readily visible in 6 to 8 inch telescopes.
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The Virgo Cluster is an extremely
dense cluster of galaxies located between Denebola, the tail star of
Leo and Vindemiatrix, the northern most star in Virgo. Virtually any
telescope under dark sky conditions will reveal hordes of galaxies.
With larger apertures, several dozen galaxies come into view. Often,
the biggest difficulty you'll encounter is determining which is which.
In this area, a good star chart is an invaluable aid. Another approach is simply to sweep slowly from Denebola to Vindemiatrix. This approach should quickly yield several galaxies. In no other area of the sky will you find so many galaxies in such close proximity as in the Virgo Cluster. With all these galaxies to choose from, an astronomer could spend quite a bit of time studying this area of the sky. |
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Our first stop in The Virgo Cluster is the giant Elliptical Galaxy M87 (mag8.6). This is one HUGE galaxy. Estimates place it between 800 billion solar masses and 2.7 trillion solar masses. Our sun, which is used for reference, weighs in at 1 solar mass. Additionally, recent studies of the galaxy indicate that the galaxy may contain a super massive black hole deep in its interior. |
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Next we come to spiral galaxy M90 (mag9.5). This is one of the larger spirals in the Virgo Cluster. | |||||||||||||||||||||||||
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| Moving on we come to our Utah Skies Challenge of
the week. Located between Vindemiatrix and Denebola, Elliptical Galaxy
M86(mag9.1) is located in the heart of the Virgo Cluster. Your
difficulty in finding this object results not from it being very dim.
Nope. It would be relatively easy find anywhere else in the sky. The
problem is that there are simply so many other galaxies surrounding
M86 that identifying it can be difficult. Look for its companion NGC
4402(mag11.75) just below it to help you identify it.
If you are able to find these object, you may be one of the few, the proud, the Deep Sky Obsessed. E-mail your findings to DeepSkyObservations@UtahSkies.org.
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Light Pollution Update
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$3.00/gallon of gas, $0.25/kw of electricity
(currently about $0.08). Why is it that Americans won't address an
issue until it becomes a crisis? Americans consume and waste energy as
if we had unlimited resources. We are affluent. No doubt. More so than
any nation that has ever existed. But we are wasteful. More so than
any nation that ever existed. I read somewhere that if the entire
world consumed as much as the average American, we would need three
planets just to support the one we live on. California often takes the lead in trend setting wastefulness. California, which is predominantly desert, actually waters the foliage along the sides of the highways to maintain the illusion that they are a tropical paradise. Well guess what? That attitude seems to fit well with many right here in Utah. Utah is predominantly desert. We have water shortages. Yet what do we do? Do we design environmentally conservative landscapes for our homes? Of course not! We plant lawns which must be watered daily to survive the hot summers. Our valleys have air quality problems. What do we do? We install miles and miles of inefficient street lighting. We build homes with enough lights on them to light entire neighborhoods. And then, to make matters worse, we leave them on from dusk to dawn. What a waste! When are we going to learn? Will we ever learn? Are you part of the problem? Or the solution? |
Next Weeks Report
Next week, we'll continue our journey through the cosmos
and focus on the constellation Ursa Major, The Big Dipper.
Closing
This "Star Cast" has been presented by Utah Skies. View-tah’s Astronomy Home. Utah Skies can be found on the World Wide Web
at http://www.UtahSkies.org. Visit
our site and discover the cosmos. While you're there, sign up to receive our
free weekly Utah Skies Report. Several of our up coming star parties will only
be announced to people on our e-mailing list.
