Report for 2001-09-28
Welcome to the Utah Skies Report.
Brought to you from beautiful Park City, "View-tah".
| Sunrise: 7:20 am | Sunset: 7:15 pm |
| Astronomical Twilight Ends: 5:49 am | Astronomical Twilight Begins: 8:47 pm |
| Moonrise: 5:58 pm | Moonset: 3:24 am |
Star Party Review
| Utah Skies would like to thank everyone who came out and made Saturday nights star party a success. Again, we would like to extend a special thanks to Chris and the folks at Snyderville Recreation for allowing us to use Trailside Park and for ensuring that all the finer details were tended to. |
Viewing Outlook
| We've been on a roll weather-wise. Warm clear skies have been overhead for a couple of weeks now. I know we need the rain, but... the clear skies are certainly a welcome treat for me. |
| The Hubble Space Telescope
has distinguished itself as the premier source of astronomical images.
Amazing HST images have graced the covers of major magazines and
newspapers worldwide. In recognition of the amazing advances in astronomy
and physics which have come from Hubble discoveries, we'd like to devote a
section of this report to share some of them with you. |
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| A Galaxy Blazes with Star Formation According to the Hubble Heritage team, NASA's Hubble Space Telescope snapped this remarkable view of spiral galaxy NGC 3310, a rare class of galaxies known as "starburst" galaxies. It seems that most "typical" galaxies form new stars at a fairly slow rate, but members of a "starburst" galaxy blaze with extremely active star formation. Scientists using NASA's Hubble Space Telescope are perfecting a technique to determine the history of starburst activity in galaxies by using the colors of star clusters. Measuring the clusters' colors yields information about stellar temperatures. Since young stars are blue, and older stars redder, the colors can be related to the ages, somewhat similar to counting the rings in a fallen tree trunk in order to determine the tree's age. The galaxy NGC 3310(mag10.9) is forming clusters of new stars at a prodigious rate. Astronomer Gerhardt Meurer of The Johns Hopkins University leads a team of collaborators who are studying several starburst galaxies, including NGC 3310, which is showcased in this weeks Hubble Vision image. There are several hundred star clusters in NGC 3310, visible in the Heritage image as the bright blue diffuse objects that trace the galaxy's spiral arms. Each of these star clusters represents the formation of up to about a million stars, a process that takes less than 100,000 years. In addition, hundreds of individual young, luminous stars can be seen throughout the galaxy. Once formed, the star clusters become redder with age as the most massive and bluest stars exhaust their fuel and burn out. Measurements in this image of the wide range of cluster colors show that they have ages ranging from about one million up to more than one hundred million years. This suggests that the starburst "turned on" over 100 million years ago. It may have been triggered when a companion galaxy collided with NGC 3310. These observations may change astronomers' view of starbursts. Starbursts were once thought to be brief episodes, resulting from catastrophic events like a galactic collision. However, the wide range of cluster ages in NGC 3310 suggests that the starburst activity can continue for an extended interval, once triggered. Located in the direction of the constellation Ursa Major, NGC 3310 has a distance of about 59 million light-years. Hubble's Wide Field Planetary Camera 2 was used to make observations of NGC 3310 in March 1997 and again in September 2000. The color rendition of the combined images was created by the Hubble Heritage Team. |
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Space Weather Update
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The level of solar activity has risen
dramatically in the last week or so. Reports of auroral activity have been
coming in from many locations to our north. Unfortunately, none have been
spotted this far south. Oh, well.
According to Spaceweather.com, "A coronal mass ejection that billowed away from the Sun on Monday, Sept. 24th, struck Earth's magnetosphere around 2100 UT on Tuesday, Sept. 25th. The impact at first seemed to herald widespread auroras. Instead, it triggered only a moderate (G2-class) geomagnetic storm with bright Northern Lights confined to magnetic latitudes greater than ~55 degrees (e.g., northern Europe, Alaska, Canada, and the northern tier of US states)." |
| The accompanying image, by Michael Theusner, was captured in the northern regions of Germany. As this dramatic image shows, we missed out on one heck of a show! |  |
| The moon will be full on Tuesday --
better get your lunar observing gear ready. With the moon this close to
full and rising just before sunset, it'll basically be with us all night.
So, why fight it? The moon is an easy target for any telescope or
binoculars. In fact, it is the only celestial object that reveals
significant detail to the unaided eye. So, what are you waiting for? Wrap
yourself up warmly and go sit out under the moon. What do you think
ancient cultures thought when they saw the moon rise? The accompanying picture performs a bit of photographic trickery. It is actually a double exposure. One capturing the background stars, the other the moon. The reason this needed to be created from two exposures is simple. The moon is so much brighter than the background stars that they would not be visible in the same image. The moon would simply overpower them. Interesting photo nonetheless. |
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| Mars is rising in the southeast around 3:25 pm. It will be high in the south-southwest by the time it gets dark. We're rapidly losing Mars. The Earth has pulled away from Mars in it's orbit causing Mars to shrink - it is currently down to a measly 11" from 21" in June. Once it gets below 10", we'll basically be unable to make out any surface detail. Additionally, it has dimmed significantly as well - currently shining at magnitude -0.40 down from -2.4 in June. Remember, each magnitude change is a factor of 2.5 so, a 2 magnitude change is 2.5 * 2.5 = 6.25 times dimmer than it's peak! Anyway...Mars reaches its Zenith, or highest point in the sky, around 8:00pm. Best views of the planet start as soon as you can find it. |
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Saturn joins us now about
10:35pm. Look for Saturn in the
east-northeast. Saturn has grown to an an impressive 19" and
currently shines at magnitude -0.05.
Saturn is brighter than any of the stars in that area of the sky. I
noticed Saturn rising the other night. To it's right was the star
Aldebaran. The most interesting aspect of this close comparison was their
visible appearance. Aldebaran twinkled wildly while Saturn didn't. Why is
this you may be wondering? Well, because of the extreme distance to stars,
they are visible only as points of light. Planets on the other hand are
much closer and are visible as disks. Because of this, stars twinkle
and planets don't. Go outside and check it out. It is this distinction
(among others) which early observers noticed which indicated that these
objects were different than the vast majority of stars in the sky. Get out there and checkout Saturn.
We had some amazing views of the ringed planet at last weekends Utah Skies
Star Party. All kinds of telescopes were pointed at Saturn during the
course of the evening. Saturn is so impressive. If it were the only thing
you could see with a telescope, it would probably still be worth the
purchase price. Anyway... The accompanying image of Saturn is is comparable to the views we had at the star party. Pretty cool, huh? As you may have noticed, Saturn is rising earlier and earlier each week. So, we'll be getting plenty of opportunities to view Saturn in the coming months. |
| Next, look for Jupiter rising around
12:30am. Jupiter is the king of the Planets. It is more massive than
all the other planets combined. Jupiter is currently shining at mag -2.22 and it
covers a whopping 38". That's almost twice the apparent size of Saturn and over 3 times that
of Mars. Jupiter is also rising earlier each week. It'll soon take is
rightful place as the star of nighttime observing targets.
I've mentioned this previously, but you have to check out the tools section of the Utah Skies website for a cool java applet which depicts the relative position of the four major moons. It's called JavaJup. Watching the orbits of these moons is fascinating. Their motion is quite apparent during an observing session. Transits and shadow transits are the most impressive events. See if you can follow a transiting moon across the surface of Jupiter. This is often more difficult than you'd think. The Earth's turbulent atmosphere often erases the fine detail required to witness these events. However, shadow transits are usually quite easy to view. The dark, inky black shadow of one of the moons typically stands out in stark contrast to the bright surface of Jupiter. The accompanying image taken by the Voyager 2
spacecraft reveals an incredible amount of detail on the giant planets
surface. Also, notice the tiny moon Io suspended out in front of giant
Jupiter.
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| Venus is the last to arrive on the scene, rising at about 5:15am. While still the brightest planet in the sky at mag -3.95, Venus is now rising too close to sunrise. So, it's brilliance is overwhelmed by the soon to be rising sun. We'll get another amazing performance from Venus late in the winter and into the spring as it takes charge of the nighttime sky. |
| 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 move on to the constellation Lacerta the lizard.
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Deep Sky Report
The focus of our efforts this week will be the deep sky objects of
Lacerta. To find Lacerta, look due north around 10:00pm. Lacerta kind of
resembles Cassiopeia, with it's "W" shape. Except, Lacerta adds a
couple of additional bends -- it is just one more bend shy of 2 connected
"W". That's where the similarity ends though. While Cassiopeia is made
up of bright stars, Lacerta's brightest is only 3.75. You'll definitely need
fairly dark skies for this object. Lacerta is just east of Cygnus and due north
of Pegasus -- constellations which we've covered in previous reports.
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Let's start things off with Open
Cluster NGC7209(mag6.75). This large, rich cluster has a diameter of 25',
roughly the size of the full moon. Located about 2900 light years away, it
is made up of about 50 stars ranging from mag9 to mag12. |
| Next up is another Open Star Cluster
NGC 7243(mag6.5). Located about 2.5° west of Alpha Lacertae, this beauty
of a star cluster should be easily within the reach of a nice pair of
binoculars. Note that this cluster seems to be divided in half -- almost
like two star clusters glued together. Use a low power when viewing this
object as it spans an area almost the size of a full moon, roughly 21'. NGC7243 is located some 2800 light years away and contains over 40 member stars.
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Next up is Open Star Cluster
NGC7245(mag9.5). This is a small cluster, spanning only around 5'. It is
however, relatively compressed towards the middle. NGC7245 is home to some
50 very faint member stars and is located at a distance of some 6100 light
years.
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| Our final stop in Lacerta leads us to
this weeks Utah Skies Challenge Object, Planetary Nebula
IC5217(mag12.6). This object covers a tiny 6" and is about 10400
light years away. Ok, so its small. This will actually help those who seek
it out. Remember, visual magnitude refers to the "overall"
brightness of the object. Therefore, if 2 objects have the same overall
brightness, but one object is smaller, it will be easier to see. This is
because the same brightness is in a more condensed region. So, you've found
IC5217? Can you see its mag14 central star? Good contrast gains have been reported with an OIII filter. Reports also indicate that IC5217 is visible as a bright compact bluish disc is visible at higher powers. Additionally, it has been described as slightly elongated. Good Luck! |
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If you are able to find all of these objects, you may be one of the
few, the proud, the Deep Sky Obsessed.
E-mail your findings to DeepSkyObservations@UtahSkies.org.
Next Weeks Report
Next week, we'll continue our journey through the cosmos
and focus on the constellation Draco.
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Stay up to date on astronomical happenings by regularly
checking the Utah Skies website at http://www.UtahSkies.org
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