Gallia Asteroid Occultation Project (148 Gallia occults HIP 43813)
Paul Maley of NASA Johnson Space Center Astronomical Society contacted Philippine Astronomical Society (PAS) last April 2009 to ask for assistance in an occultation research project.
Zeta Hydrae, a 3.1 magnitude star located in the head of constellation Hydra, will be occulted by the Gallia Asteroid for about 3 seconds at 4:13:42 am on October 1, 2010. The shadow will pass the northern Luzon of Philippine Islands. As mentioned in PAS’ Preliminary Report, this occultation is one of the must observed event in 2010 because occultations of bright stars are very rare.
PAS asked for volunteers for this project. Members who participated were from Rizal Technological University Astronomical Society (RTU Astrosoc), Quezon City Science High School, Philippine Astronomical Society, and University of the Philippines Astronomical Society (UP Astrosoc).
On behalf of the U.P. Astrosoc team, I would like to thank PAS for giving us the opportunity to participate and contribute to the scientific community. It will always be a great learning experience for all of us.
To the stars!
Below is our team’s observation report of the asteroidal occultation: (To see the observing reports of each team, click here.)
GALLIA ASTEROID OCCULTATION PROJECT (148 Gallia occults HIP 43813)
Observation Report of Team Delta (U.P. Astronomical Society Astro-Imaging Group)Sept. 30 – Oct. 1, 2010
by Anthony Urbano, Erika Valdueza, Sigrid Batongbakal, and PB Jane Quimba
The team was dispatched to the assigned observation site (16d 36m 44.7s N, 120d 21m 01.2s E) in San Fernando, La Union at around 2:00 a.m. on October 1st. Upon arrival, an ocular inspection was performed to assess the safety of the area and to find a place for equipment setup. To the group’s surprise, the observing point was at the middle of a rice field, with two to three cows lying around and a guard dog to complete the rusticity. The view of the western horizon was free from obstruction. The eastern horizon, however, was blocked by treetops. The group managed to find a spot to set up their equipment.
They immediately assembled their telescopes, synchronized timers and GPS, and tested the laptops and video cameras. At 2:30 a.m., everything was set except for the weather. Clouds covered the whole sky. This caused observing conditions to be fair in seeing and poor in transparency. The moon, Sirius (brightest star in Canis Major), the constellation Orion in the east, and Jupiter in the west were hardly visible.
At 3:00 a.m., Procyon (brightest star in Canis Minor) was discernible despite unchanging weather conditions. While waiting for the sky to clear up, Anthony, the observation leader and operator of the first video camera setup, performed a systems check and took a video of the moon, Sirius, and Procyon using a Canon Legria FS20 video camera through a 6-inch f/5 Newtonian reflector. Erika, the operator of the second video camera setup, then took a video of Sirius and Procyon using an 8-megapixel Olympus FE-250 digital camera through a 3-inch TMB Triplet Apo Refractor. Both telescopes used were equipped with tracking mechanisms.
The group’s video setup consisted of 1) a video camera, which was attached to a telescope, sending audio and video signals to 2) a laptop computer inserting timestamps to the video field (the computer was using a timer program that displays time accurate up to 1/100 of a second) and saving the time-stamped video file into its hard drive, and 3) a backup laptop computer monitoring and recording all activities.
With merely an hour left before the key time, Sigrid, the group’s visual observer, used a pair of 10×50 binoculars to navigate the sky and looked for Zeta Hydrae, a 3.1-magnitude star in the constellation Hydra that will be occulted by asteroid Gallia for 3 seconds at approximately 4:13:42 a.m. The group’s timer, PB, started to perform time checks and a countdown sequence to alert the group of the remaining time. Castor and Pollux in constellation Gemini started to appear at 3:30 a.m. but there was still no sighting of the target star. 4:10 a.m., conditions have not yet improved. The group started to lose hope of witnessing the astronomical event.
On the timer’s cue 2 minutes before key time, the cameras started recording, but due to poor seeing conditions, Zeta Hydrae was only seen a minute after the asteroidal occultation. Its sighting was confirmed by the group’s visual observer.
The Astro-Imaging Group (AIG) of UP Astronomical Society, despite the one-minute miss, was more motivated and determined to hunt for future occultations. The difficulties and sacrifices for this 3-second event served as both blessing and inspiration to the team to be more fascinated, more curious, and more in loved with the stars.