25th August, 2017, USTM : Astronomical events like solar eclipse and lunar eclipse are very exciting natural events which repeat after long duration. During a solar and a lunar eclipse the sun and the moon, respectively disappears for few hours partially or totally. People eagerly wait to witness such events while scientist performs different experiments under the condition of such eclipses. Seizing the opportunity of Lunar Eclipse that occurred on 7th August 2017, visible from all the parts of India, the Department of Physics at University of Science and Technology, Meghalaya (USTM), had conducted a scientific experimentation on Lunar Eclipse.
A group of M.Sc. Physics students, Mr. Mrinmoi K. Bora, Mr. Ariful Alom, Mr. Rakesh G. Chetry and Mr. Ikbal Farid Ali have developed USTM’s first optical telescope, “Astronoscope-I” (Newtonian Reflector Type), under the supervision of Mr. Nitu Borgohain, Assistant Professor, Department of Physics. Astronoscope-I initially has the maximum magnification 450X, which will be increased in the upgraded versions of this telescope series. During the time of the eclipse students and faculties of different departments gathered to witness the event but due to heavy cloud the initial phases of the eclipse have missed. After 5 hours of wait few windows of partially clear sky for 2-3 minutes have been found, which were not to let go in vain and finally, the lunar eclipse has been captured successfully at 11:45PM.
How Astronoscope-I was made?
The major parts of Astronoscope-I are the Telescope Tube and the Mount. The Telescope Tube contains a convex primary mirror of aperture diameter 4.5 inch and focal length 900 mm at the bottom end, an oval structured flat secondary mirror near the open tube end and a focuser that holds the eyepieces mount outside the tube, near the secondary mirror. These mirrors are bought from a Mumbai based company which costs are around Rs. 5000 only. The telescope tube is made from a 1 meter long PVC pipe of diameter 5.5 inch. The holder clamps of the tube are made from scrap iron bars available in the RIST workshop. The mount that has been developed is a modified Dobsonian type which suspends the telescope with the help of nut-bolt. A scrap revolving chair is used for this purpose where the seat has been replaced with a plywood mount made by the students.
How Astronoscope-I works?
Light enters the open end of the tube, travels down to the primary mirror. The focused image then reflects back to the small secondary mirror which is placed at an angle of 450 with the primary mirror. Secondary mirror reflects the image out through the side of the tube to the eyepiece where it enlarged the object.
Magnification power of Astronoscope-I:
Magnification power of this type of telescope is given by the ratio of focal lengths of the primary mirror to the eyepieces. We have 3 different eyepieces viz. 20 mm, 12 mm and 4 mm, for which corresponding magnifications with a 2X Barlow lens are 90X, 150X and 450X (maximum). Thus with the help of Astronoscope-I, any distant object in the night sky can be viewed maximum 450 times closer then they appear.
What Astronoscope-I can gaze in the night sky:
The whole universe could be viewed in the night sky. Moon is the easiest target to find at night. The craters and mountains of the moon can be studied in much details with Astronoscope-I. Other planets of the solar system such as Venus, Mars, and Jupiter can also be viewed. Rings of Saturn may be spectacular to be observed too. Astronoscope-I also can be used for gazing the galaxies, nebulae and star clusters abound in the deep sky and study their formations.
Future Developments to Astronoscope-I:
Currently, Astronoscope-I has to be operated manually for targeting an object in the sky. In the nearest future, this discrepancy is to be removed with a digital orientation system. A tuneable eyepiece system attached with a HD camera also to be developed soon.
Department of Physics acknowledges the financial support from Mr. M. Hoque, Chancellor, USTM.