Last 13 January 2011, an International Space Station (ISS) Solar Transit event visible in some parts of Metro Manila occurred at around 8:30 am PHT (Philippine Time). The relative rarity of ISS Solar and Lunar Transits here in the Philippines plus the fact that I were fortunate enough to be very near the path of visibility of this transit inspired me a lot not to miss this event.
Along with my UP AstroSoc orgmates and some fellow amateur astronomers from RTU AstroSoc and from the Philippine Astronomical Society (PAS), we set up our equipment to observe this passage of the ISS in front of the Sun’s disk at the Manila Observatory in Quezon City, Philippines.
I already have some experience in observing solar eclipses but this was my first time to try timing and capturing a solar transit. Unlike eclipses, ISS transits are more challenging to observe because they happen too fast. To give you an idea of how fast these events occur, here is a video clip which I got from Youtube showing the ISS transiting in front of the Sun’s disk. It was captured by students of the Westfalenkolleg Dortmund on August 7, 2010 at 17:31 pm.
The transit above lasted for 1.06 seconds. The one we were to observe will have a duration of about 0.91 seconds — too swift to be captured using cameras so we opted to record a video of it instead.
Following are the transit details including the timings. The data was obtained by our UP AstroSoc orgmate and team leader, Anthony Urbano from www.calsky.com. All times are in PST (Philippine Standard Time) or UT+8.
Distance from center-line: 1.06km
Path Width: 13.6km maximum
Time of Ingress: 8h30m40.6s
Time of Egress: 8h30m41.6s
Transit Duration: 0.91s
Separation Angle: 0.037°
Position Angle: 121.2°
Satellite at Azimuth: 123.6° ESE at culmination
Satellite at Altitude: 26.4° at culmination
Angular Diameter: 25.6″
Angular Velocity: 35.2’/s
Ground Velocity: 7,457m/s
Size: 73.0m X 44.5m X 27.5mSatellite Distance: 723.6km
In clock-face concept, the space station will appear to move toward: 8:58
And by the way, Anthony Urbano or Kuya Eteny, as we fondly call him, is a gadget master. 😀 He has invented a lot of devices like a universal camera adapter that allows any point-and-shoot camera (and even SLRs) to be attached to any optical system (binoculars, telescope, microscope, etc.). He even brought one of his camera adapters during this observation to attach the video camera to his 6″ Newtonian Reflector Telescope. Moreover, he has also modified some gadgets like DSLRs to be more useful in astronomical observations and astrophotography. This guy is truly remarkable for possessing such great talent! 🙂
An hour before the ingress, the sky around our location was partly covered in clouds. The sky condition got even worse as the predicted time approached. We waited for several more minutes, just in case the clouds clear up and the actual time of transit is later than predicted. In the end, we didn’t see any trace of the ISS due to thick cloud cover. We packed up and left at around 9:30 am.
Though we were not able to accomplish our goal of recording this transit event, the experience is always worth it. 😀 Thanks to Kuya Eteny for informing us about this event and inviting us to observe with him.
I’m looking forward to more transit and solar observations. 🙂
*Photos by Bea Banzuela
Update: Another group of fellow Filipino amateur astronomers from the Astronomical League of the Philippines (ALP) were lucky enough to observe and take images of the ISS transiting the Sun. Their observation report and images can be found here.
Despite the 50% predicted cloud cover and significantly large uncertainty in the precise time of the peak, I and some of my orgmates in UP AstroSoc tried our luck in observing the first meteor shower of the year during the night of January 3 until the dawn of January 4, 2011. According to British meteor astronomer Alastair McBeath, the narrow peak of this shower is predicted to occur some time between 2100 UT on 3 January (5AM on January 4) and 0600 (UT) on 4 January 2011 (2PM on January 4), however the radiant of the shower is very low in the evening hours, and will rise higher towards dawn so the best time to view this event in the Philippines was during the predawn hours of January 4.
This was my first time to observe the Quadrantid Meteor Shower. Unlike the other popular annual meteor showers like the Perseids, Leonids and the Geminids, this shower is expected to be less spectacular due to lower activity and unfavorable position of the radiant to a country near the equator like the Philippines. Nevertheless, the moonless night during January 4 and 5 enticed me to give it a chance.
We chose to observe in Marikina City, at a friend’s house which has a roof deck. From there, we had a fine view of the north and eastern sky wherein most of the Quadrantids are expected to pass.
The radiant of the meteor shower which is found a little below the Big Dipper and beside the constellation Bootes, was set to rise at around 1AM of January 4. While waiting, we spent the time preparing our simple reclining chairs and sleeping bag which we intend to use as a mat where we could lie down. We also set up our organization’s 4.5″ Meade Reflector — which we fondly called Datascope — to look for deep sky objects. We pointed it first at the famous stellar sisters, the Pleaides or M45, in Taurus. We enjoyed stargazing and constellation-hopping because the sky was fairly clear then.
At around 1:30 AM, I saw my first Quadrantid. 😀 It was a short and swift one having a thin trail and a pale bluish big head, typical of a Quadrantid meteor. It passed between the pointer stars, Dubhe and Merak in Ursa Major. It was an amazing scene!
After about 30 minutes, patches of clouds began to block our view. We decided to pause our observation for a while to pick up a friend who would join us.
We continued on our observation with a less cloudy sky (around 40% cloud cover) by 3:20 AM during which we saw another Quadrantid passing near Corona Borealis. Another one zoomed past by the Bootes at 4 AM.
At 5 AM (21:oo UT), during the time of the peak we saw more meteors flying across the northeast in between cloud gaps of the 50-60 % clouded sky. In my previous post, I calculated for the number of meteors that could be seen given the 50% cloud cover and 4.0 limiting magnitude using the formula given by IMO. The actual meteor count we got during the peak is 6, which was relatively comparable to the 8 meteors per hour which I had calculated. 🙂
By 5:40 AM, we also saw one artificial satellite flying from the northwest. During this time, Venus and Mercury were already shining high in the east though they seemed to disappear from time to time as clouds pass in front of them. We also took sometime to capture a few bright constellations like my favorite, Crux in the south.
We ended our observation at past 6:00 AM when the Sun started to climb up in the east. A beautiful sunrise greeted us as we finished our observation and ate our breakfast — McChicken Fillet Meal from McDonalds — courtesy of our friend Saeed, who had his birthday during that observation.
The following night two of my fellow UP AstroSoc friends — Bea and Aaron — went to Seven Suites Hotel Observatory in Antipolo City, accompanied by some of our UP AstroSoc associates, to observe the Quadrantids from there. The sky there offers a more favorable viewing condition because it was farther from the light-polluted city. They were even lucky to have less cloudy sky during that night. 🙂
Below are some of the pictures taken during their observation at the Seven Suites Hotel Observtaory. All images are by Bea Banzuela.
I never expected that this event would turn out to be another memorable and fun observation. 🙂 Thank you, UP Astrosoc!
To all those who were able to say hello to this year’s Quadrantids, congratulations and good luck on your observation of the next meteor shower. 😀