My experience at the 40" observatory at Kavalur

By akarshsimha; Published 13 Jul 2007

I'd like to share my experience at the Vainu Bappu Observatory, Kavlaur, where I stayed and observed from 9th June to 12th June 2007. The Observatory housing the Zeiss 1m Telescope

The observing team, who observed on behalf of Dr. B.S. Shylaja and Dr. R.C. Sarasij of the Jawaharlal Nehru Planetarium Bangalore, consisted of Mr. Prasanna Kumar, Mr. Bhavani Prasad, Mr. Santosh, Amar, and me. The equipment used was the Zeiss 1 metre telescope attached to the Universal Astronomical Grating Spectrograph (UAGS) at Cassegrain Focus and 1 Megapixel CCD detector.

It was a very enjoyable experience working with a professional telescope and doing scientific observations instead of the regular visual observations we do just for fun. The intent of Dr. Shylaja was to give us students an exposure to astronomical spectroscopy. We took the spectra of several bright objects including Jupiter and Venus. While taking long exposure spectra, the telescope requires to be guided manually. On two occasions, Amar and me manually guided the telescope using the handpad. It was exciting to see a humongous telescopeThe Zeiss 1m Telescope being moved by the push of a button on the handpad!

The less transparent, hazy skies at Kavalur, are probably equivalent to the best skies at Hosahalli! On the clearest of the 4 nights we spent there, we could see the fainter parts of the Milky Way, which we have observed only once from Hosahalli! The light pollution levels at Kavalur are very low and we loved to sit (or even sleep!) on the corridor running around the observatory and do some binocular observations while long exposures were going on.

Interestingly, the observatory recieves a host of Radio stations, including ones from Bangalore and Chennai, despite being so remote, and music warded off our sleep and kept us awake during long, jobless exposures! (while someone else did the guiding)The Zeiss 1m Telescope

Skies are generally bad at Kavalur during June, as they are everywhere in South India. Out of four nights that we spent there, one night was completely cloudy. Sky transparency was bad, and on some occasions seeing was bad as well. Sometimes humidity shot up beyond 80% and on some occasions there was heavy lightning, which is detrimental to the electronic equipment. During such times, we took a look at few objects through the 8" finder scope and the 1 metre telescope. The 8" f/15 refractor which is used as a finder scope for the 1 metre telescope is of excellent optical quality. We saw Jupiter, Saturn and Venus through it (at about 170x) and the views were simply enthralling. Amar tried sketching Jupiter during an exposure with Jupiter in the field. The 1 metre telescope was not focussed at the eyepiece but rather at the spectrometer, so the views through it were not as appreciable. Nevertheless, aThe eyepiece on the UAGS, through which we made visual observations 40-inch (1 metre) is a 40-inch and globular cluster M22 (in Sagittarius) was completely resolved through the 40-inch telescope and the Dumbbell Nebula (in Vulpecula) and Blinking Planetary Nebula (in Cygnus) were very beautiful. The magnification of the 40-inch telescope is so high, that Dumbbell Nebula nearly covered the whole field!

During the day, we learnt to use IRAF (Image Reduction and Analysis Facility, a very powerful program with tools for optical observational astronomy) to reduce the spectra we had taken. IRAF is the outcome of programming genius - the way it does complicated image processing and numerical analysis has left me flabergasted! (Reduction of spectra refers to converting the image of the spectrum as taken by the CCD detector into a intensity versus wavelength graph by applying various corrections).

We learnt a lot working with the telescope and spectrograph... lots of technical details, lots of techniques, lots of scientific details. We alsoPouring Liquid Nitrogen into the CCD got to talk to veterans like Mr. K. Kuppuswamy. (co-discoverer of Ring system around Uranus)

All thanks to Dr. Shylaja for sending me there. I hope to go there again, for everything including the guest house, the scenery from the corridors of the 40" observatory, the extremely helpful people of the like of Dr. Muneer, the sight of the 40" moving, the views through the 40" and 8", the process of spectroscopy, amounted to a wonderful experience.

Check out Amar's Kavalur Album for full size pictures.