Planetarium Observation

Observing an astronomical object was always my fascination which never came into reality until yesterday. Yesterday, 21st April, was 'Planetarium Open House' at the Physics Department in Drexel University. I always wanted to observe a galactic object with the help of a powerful telescope. It first popped up in my mind when I was in Rajshahi Cadet College in 1997. It was the appearance of the Comet Hale-Bopp, Comet of the Century, that aroused my interest for astronomical object observation. I wished few times but could never make it to reach any of the observatory while at Bangladesh. Yesterday I took the chance when I got the news-letter from Drexel about the event.

The event was spectacular as I watched some stars and saturn using 3 different telescopes. I went to the rooftop of Curtis Building, Drexel University around 9 PM. It was dark out there. One professor was presenting the event with the frequent interruption of Question/Answer session. Two telescopes were placed under open sky, one was pointing at 'Saturn' and other was at '? Shaped constellation'(I forgot the name though). There was a computer-assisted telescope with 400x Magnification which was aligned towards 'Saturn'. Professor and one of his students were always adjusting the foci of the telescopes. Because, like Sun, the stars and planets also rotate around the sky during the night. They rise on the horizon along an orbit and sets on the other end of the orbit.(Exception is there as well: relative rotation of the '? shaped constellation' places them where it rises at the sky). Watching Saturn was splendid experience, as I saw bright circular object with a disk around it. There were 3 to 4 moons, seemingly bright spots, visible around the disk. I tried Saturn using both the telescopes. We were also given an opportunity to buy a galileoscoope, a telescope of moderate power. I bought one for 9 dollars. I thought if I ever get a chance I would point it towards moon, jupiter and saturn. I came back from there around 10 PM.

It was great experience that educated me from a misconception of Astronomy. I thought that stars twinkle. My surmise was since star has its own light that is why it flickers; where as planet reflects lights. But in reality both could be seen non-flickering if enough lights can be gathered from stars or planets. Twinkling happens for the atmospheric particles like air, dust, vapour et cetera. They deflects light coming from the source(star) that is why when we watch them in naked eye it creates a wobbling effect. If we calibrate a powerful telescope so that it can gather sufficient light coming from a star, it will appear like any other planet. The distance of stars are many times larger than the distance of a planet from earth. The relative distance of the star is the reason which does not allow enough light to reach on the surface of the earth. Different planets can be visible at different times of the year. Saturn and Jupiter are visible in different time-frames of the year. At this time of the year Saturn rises on the south-eastern part of the sky at night. Magnification is not only the reason for which we can see the universal objects. Telescope has a lens at the end which is focused to the object. The diameter size determines how much light it can refract inside the funnel. The diameter of human eye lens is 18mm, which can refract little amount of light. But a larger telescope has a huge lens which refracts great amount of light. The refracted light is magnified by some factor before protruding that light towards our eye. Telescope is represented by two important numbers representing these two process: Intial Refraction and Final Magnification. To get a better view of the astronomical object, it is better to view them from a country area(rather than an urban place like Philadelphia). Because whole thing depends on the collection of light omitted from the celestial object. In the urban place when we look at the artificial light at night it ignites some chemical reaction on our eyes. In order to prepare our vision ready for sky-object observation we need to keep our eyes close for at least half an hour. This process hindrances our planetarium observation. In country side there is less light than urban night glowing. To achieve even more suitable sight of the sky-objects, the observatory are placed on high hilltop where there is less dust, stable air-flow etc among many other factors.

Above all it was an enjoyable experience that also entails some educational benefits. It also left in me the impetus for further observing the celestial objects at night.

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