DUE TO THE IMPACT OF CURRENT EVENTS, SOUTHERN CROSS ASTRONOMICAL SOCIETY IS CANCELLING ALL PUBLIC OUTREACH ACTIVITIES UNTIL FURTHER NOTICE. NORMAL OPERATIONS WILL RETURN AS SOON AS IT IS DEEMED SAFE TO DO SO. THANK YOU FOR YOUR UNDERSTANDING AND COOPERATION.
SCAS AUGUST 2020 - Compiled by Barb Yager
Full Moon August 3rd @ 11:59 am
Last Quarter Moon August 11th @ 12:45 pm
New Moon August 18th @ 10:42 pm
First Quarter Moon August 25th @ 2:00 pm
METEOR SHOWERS THIS MONTH
Each July and August the Earth encounters debris left behind from comet 109P/Swift-Tuttle. This comet has an orbit of 133 years and last entered the inner solar system in 1992. Even though the comet now lies in the outer portions of the solar system, far away from Earth, we still encounter debris that has been left behind during the many trips this comet has made through the solar system.
August 11th / 12th
To view the Perseids at their best, you need to know when to watch. During the evening hours the radiant, the area of the sky where Perseid meteors shoot from, is located low in the northern sky. This is the worst time to try and view the shower for sheer numbers as most of the activity will occur beyond your line of sight, being blocked by the horizon. The few that do come your way this time of night are special. The reason is that they just skim the upper regions of the atmosphere and will last much longer than Perseids seen during the morning hours. Since they last longer they also will travel a much longer distance across the sky. Most of these “earthgrazing” Perseids will be seen low in the east or west, traveling north to south. Occasionally one will pass overhead and will be unforgettable as you watch it shoot across the sky for several seconds. While these meteors are few, they are certainly worth the effort to try and catch. Since the moon will interfere with morning meteor observing, more emphasis should be on viewing prior to midnight this year.
As the Earth rotates and the time approaches local midnight, the Perseid radiant has risen higher into the northeastern sky. The meteors are now shorter and last only a few tenths of a second. You still only see about half of the actual activity as the remainder still occur beyond your line of sight. As the morning progresses, the activity will increase as the radiant climbs higher into the sky. Theoretically, the best time to watch the Perseids is just before the break of dawn when the radiant lies highest in a dark sky. This is usually around 04:00 local time. Experienced observers often say the hour between 03:00 and 04:00 is usually the best, not 04:00 to 05:00. Perhaps this is due to fatigue as experienced observers have watched for several hours by then and may have trouble staying alert.
The strongest Perseid rates this year are expected to occur on the Tuesday night/Wednesday morning August 11/12, when the Earth closest to the core orbit of comet 109P/Swift-Tuttle. If you cannot observe on that night activity will still be good on Monday and Thursday. The further you watch from August 12, the weaker the display will be. To view the Perseids successfully, it is suggested you watch from a safe rural area that is as dark as possible. The more stars you can see, the more meteors will also be visible. No matter the time of night, Perseid meteors can be seen in all portions of the sky. No matter which direction you look, it is advisable to aim your center of view about half-way up in the sky. Don’t look straight up as more activity is visible at lower elevations. Some observers like to view toward the constellation Perseus and the radiant. This way they can see Perseid meteors travel in all directions. The disadvantage of viewing in this direction is that the Perseid meteors will be short, especially near the radiant. The other choice is to face away from the radiant and witness longer meteors, which are more impressive. Even if the radiant is at your back, you can still distinguish Perseid meteors from others as they will all travel in the same parallel paths and will have similar velocities.
Here are some tips on how to maximize your time looking for meteors and fireballs during December:
- Get out of the city to a place where city and artificial lights do not impede your viewing
- If you are out viewing the shower during its peak, you will not need any special equipment. You should be able to see the shower with your naked eyes.
- Carry a blanket or a comfortable chair with you - viewing meteors, just like any other kind of stargazing is a waiting game, and you need to be comfortable. Plus, you may not want to leave until you can't see the majestic celestial fireworks anymore.
BRIGHT COMETS THIS MONTH
COMET 2002 F3 NEOWISE MAG 7.1
The comet is climbing higher thru Comea Bernices and into Virgo this month.
At 10 pm looking west north west @approximatley 280 degrees, the comet is still 27 degrees above the horizon.
Astronomy/Sky & Telescope magazines
Abrams Planetarium, MSU