Last December 13, I went to the PAGASA Astronomical Observatory in U.P. Diliman to observe the peak of the 2010 Geminid Meteor Shower with my amateur astronomy group, the University of the Philippines Astronomical Society (U.P. AstroSoc).
When I came at around 11:00 PM, about 50 people were already at the Sun Deck of the observatory. Everyone was enthusiastically waiting for the bright Geminid meteors despite the growing chance of an overcast sky. The other guests set up their personally-owned telescopes to view the Great Orion Nebula and other deep-sky objects not blocked by clouds.
Amidst the 40% cloudy sky, the constellation Gemini where the meteors seemed to radiate from could be seen at ~40 degrees above the northeastern horizon. In the west, bright Jupiter and the First Quarter Moon were already about to set. The pair looked beautiful as they went lower in the horizon and become partially covered behind the tree tops.
As moonlight disappeared, the sky become darker and more favorable for meteor watching. Four big and bright fireballs zoomed across the sky before midnight. 😀 Unlike other meteor showers, the Geminids can appear almost anywhere in the night sky, making them fairly easy to spot.
However, this short-lived outburst was soon replaced with an overcast sky which lasted until about 2:00 AM. During this time, I took the chance to go online and update my twitter status regarding our observation (I was able to do this thanks to Sun Broadband plug-it!). Several groups locally and internationally were also sharing their meteor counts and meteor watching experience. Below is a screenshot showing some of my tweets during that time.
As what I have noted there, the Observation and Instrumentation Cluster (ObsIn) of U.P. AstroSoc kept a record of the tally* of the number of meteors seen every hour during the Geminids observation.
Limiting Magnitude**: ~4.0
Dec. 13, 2010
22:00 – 23:00 —— 27
23:01 – 24:00 —— 29
Dec. 14, 2010
00:01 – 01:00 —– overcast sky
01:01 – 02:00 —– overcast sky
02:01 – 03:00 —– 20 (with one green fireball!)
03:01 – 04:00 —– 2
04:00 – 05:00 —– 0
prepared by: Francis Bugaoan and Carlo Selabao
* This report just shows the number of meteors seen.Values listed above are the max. number of meteors observed within each time frame which means that it includes all meteors seen by at least one person. These are not the computed Zenithal Hourly Rate (ZHR) of the meteor shower.
** This is used to evaluate the quality of observing conditions. It tells the magnitude of the faintest star visible to the unaided eye
By around 2:00 AM, clouds began to moved away which allowed us to continue on our meteor counting. One green fireball which crossed the northwest sky appeared like a falling big blob of light. 😀 Everyone cheered happily upon seeing it. It lasted for about 5 seconds before disappearing into view.
More than an hour later, Venus which is now a “morning star” lit up the eastern horizon together with Saturn, Spica and Arcturus. Gemini was then past the zenith while my favorite Winter Triangle was already in the west.
Because of this beautiful pre-dawn sky, U.P. AstroSoc members took the opportunity to lead the guests into a star-hopping activity to familiarize them with these celestial objects and the constellations.
As sunrise approached, one member noticed a rarely seen atmospheric phenomenon called the Belt of Venus. It is an arch of pinkish band above the shadow that Earth casts on the atmosphere opposite the sunrise or sunset. It is best visible when the atmosphere is cloudless, yet very dusty, just after sunset or just before sunrise. The arch’s pink color is due to backscattering of reddened light from the rising or setting Sun.
We finished our observation at around 6:00 AM. A lot of the guest observers who came by told us that they enjoyed the meteor counting, as well as the stargazing activities and they’re looking forward to the next meteor shower observation.
Despite the cloudy weather, I was surprised that the Geminids still gave us a fairly spectacular cosmic show. Truly, this shower never fails to live up its reputation as the best meteor shower.