St. George Astronomy Group
The St. George Astronomy Group is an informal association of amateur astronomers in St. George, Toquerville and other nearby communities in southwest Utah.
The group was formed to (a) exchange ideas and
foster fellowship among people with an interest in astronomy, (b) to host
public star parties, and (c) to promote proper lighting and dark skies over southwest Utah.
are no officers, dues, or formal meetings. Membership is open to anyone who
wishes to actively participate in hosting star parties and working for dark
skies over St. George.
People who wish to know about the group's public activities can join our mailing list
Public Invited to View Perseid Meteors
In Unity Park, Ivins
Wednesday, August 12, 2015
The St. George Astronomy Group invites everyone to view the annual Perseid Meteor
Shower at Unity Park in Ivins on Wednesday night, August 12. The meteor party begins at 9
p.m. and lasts until 11 p.m. There is no charge and all are welcome.
Each night of the year several meteors fall at random, but every August 12 the earth passes
through a swarm of meteor particles and we experience a “meteor shower.” Then an
observer under clear dark skies might see up to one meteor a minute.
These meteors actually come from comet dust. They originate from Comet Swift-Tuttle,
named after the two American astronomers who discovered it during the Civil War. When the
earth passes near that comet’s orbit, we plow through a swarm of dust debris shed by the
comet long ago and that follow in the comet’s orbit. The comet dust falls through our
atmosphere at the incredible speed of 37 miles per second – 133,000 miles per hour – and
burns up due to friction with air molecules. Comet Swift-Tuttle last passed by in 1992 but its
meteors fall at the same time each year. These meteors appear to radiate from the direction
of the constellation Perseus, which is in the northeast, and are called Perseid Meteors.
No telescope or even binoculars are needed to view meteors, but it is essential to be comfortable.
Bring a folding lounge chair or blanket to put on the ground and warm clothing, and
watch for meteors while an amateur astronomer talks about meteors and comets and points
out constellations. A telescope will be set up to view the planet Saturn and its amazing rings.
The star party will be held on the south side of Unity Park on 400 South midway between 200
West and 400 West, on the lawn. Parking is available on 400 South and in the parking lot
one block to the east.
Public Invited to Star Party
Friday, September 11, 2015
Star Party for the town of Leeds to coincide with their Wild West Days celebration on . Location, outside of the Cosmopolitan and Silver Reef Museum. Wild West Days is a joint effort involving the Town of Leeds and the Silver Reef Museum. A new moon occurs on , so we should have a dark night sky. The Star Party would follow a concert and play in the Town Park.
Public Invited to View
Total Eclipse of the Moon
In Unity Park, Ivins
Sunday, September 27, 2015
Residents of St. George and surrounding communities – and the entire United States – will be treated to a total eclipse of the moon on the evening of Sunday, September 27. The St. George Astronomy Group will offer free public viewing with telescopes at Unity Park in Ivins. This is the last total eclipse of the moon visible from Utah for almost 2½ years.
An eclipse of the moon happens when the moon moves into the shadow of the earth and grows dark. This can happen only at full moon, when the moon is opposite the sun in the sky. Usually the moon’s orbit takes the moon above or below the earth’s shadow and in most months there is no eclipse, but if the alignment is just right the moon can move into and through the shadow, and for an hour or so the moon grows dark as sunlight is blocked by the earth.
The visible phase of the eclipse begins at 7:07 p.m. MDT when the moon begins to move into the inner (umbral) part of the earth’s shadow – but as seen from St. George the moon does not rise until at least 7:19 p.m.! This rising time is calculated for a perfectly flat horizon and in reality it will be at least several minutes and likely much longer before the moon rises above hills to your east and actually becomes visible to you. The time that you will first see the moon depends on the height of hills and mountains to your east, so for best viewing find a place with a low eastern horizon (or be prepared to wait until the moon rises from your location).
At moonrise the moon has moved only a short distance into the earth’s shadow and the moon’s left edge is noticeably darker than the rest. During the next hour the moon moves deeper into the earth’s shadow and the shadow creeps across the moon’s face, moving from left to right. At 8:11 p.m. the moon moves fully into the earth’s shadow and totality begins. At that moment the moon is a scant 9 degrees above the true horizon.
The eclipse is total from 8:11 p.m. until 9:23 p.m. with mid-eclipse at 8:47. When totality ends at 9:23 the moon is 23 degrees high (1/4 of the way up the sky) and a bit south of due east. The eclipse is partial for the next hour as the moon slowly moves out of the earth’s shadow, and the eclipse ends at 10:27 p.m.
Assuming that the moon is above your local horizon, the best time to look is around 9 p.m. when the moon is deep in the earth’s shadow.
Note that the sun sets as the moon rises, so the sky is quite bright at moonrise. The brightness of the early evening sky may make it hard to discern the partially eclipsed moon.
The moon darkens when in the earth’s shadow, but it doesn’t disappear. Sunlight refracted around the edge of the earth and through the earth’s thin atmosphere, falls on the moon, and this refracted sunlight is reddened for the same reason that sunsets are often red – red wavelengths of light penetrate the atmosphere better than other wavelengths. The moon usually takes on an orange or red color that is caused by light from all the sunsets and all the sunrises of earth!
If you were on the moon at this time, you would see the earth move in front of the sun in a total eclipse of the sun. Perhaps future astronauts will enjoy such sights from their lunar bases.
The St. George Astronomy Group (SGAG) will set up telescopes for free public viewing of the eclipse at Unity Park in Ivins on 400 South midway between 200 West and 400 West. Parking is available on 400 South and in the parking lot one block to the east. Viewing begins at moonrise shortly after 7:30 p.m.
If you’re not able to attend the St. George Astronomy Group viewing in Ivins, merely step outside, face east, and enjoy the free show. Binoculars will enhance the view. While watching the moon, pause to notice the planet Saturn very low in the southwest. Saturn is the sole planet in the evening sky, and it sets at 10 p.m. Saturn is in Scorpius, whose stars stretch to the lower left of the planet. The bright stars of the Summer Triangle – Vega, Deneb, and Altair – are high overhead.
The eclipse is visible simultaneously from all of North America and Europe, although the farther east you are, the later the eclipse happens (because of time zone changes) and the higher the moon appears in the sky. Adjust for the local time zone if necessary.
The next eclipses of the moon visible from Utah are a total eclipse on the morning of January 31, 2018, and another total eclipse on the evening of January 20, 2019.