Laser Pointers in Stargazing!

Our fingers are great tools. We use them to eat, pick our noses, and of course, point at things. However when pointing at things in the sky, fingers usually aren't long enough. When one beckons at a star overhead to a friend, he/she often meets cries along the lines of "Where? Where? What? That one? WHERE?" Modern laser pointers have changed that situation.

Laser pointers are instruments capable of producing powerful beams of light, which can be seen scattering in the lower atmosphere, and make it easy to point out astronomical objects. Generally, astronomical laser pointers are green and more powerful than standard ones used for presentations and such. Even though red lasers are the standard and can propagate the longest distance without scattering, green lasers are preferred for celestial pointing. This is because the human eye is much more sensitive to green light than red light. These usually use a neodymium diode core as the main component of the instrument.

Generally, the units used by astronomers have a power rating of no more than 5 mW. Nonetheless, these can still be harmful if the beam hits the human eye directly. A standard pointing laser viewed at point blank range will appear brighter than the sun, and since the rays are aligned and coherent, they can cause severe damage to the retina. Industrial class lasers can blind you instantaneously. (Lasers can be pretty darn dangerous!) 

Another hazard of lasers arises from a rather ironic reason - pointing them at the sky. Celestial objects aren't the only thing you can see above you. The sky is 'inhabited' by aircraft flying overhead frequently. The risk of the laser beam hitting the eyes of a pilot or messing with instruments is extremely worrying, and could potentially lead to a disaster. Because of this, several countries have regulations regarding laser pointers, even requiring the people owning the higher power lasers to register with government authorities. There are cases of people who have pointed lasers at airplanes, been reported by the pilots, and subsequently been arrested. This is a serious issue. Clearly, with great power comes great responsibility.

Laser pointers are a wonderful thing. When used right, they can be extremely handy astronomical aids and help bring to the joy of astronomy to everyone.

THIS IS A 5mW GREEN LASER POINTER PRESENTED TO US BY ONE OF OUR CLUB FOUNDER, CEE!

Content writer: Venkatraman Srikanth (1st year, Nakshatra)

My best experience in astronomy

Posted this is in a facebook astronomy group, in which someone had asked which was my most beautiful experience in astronomy:

Some 6 years ago, I just bought my first telescope (which I am still using). I was looking for the Andromeda Galaxy and could not at all find it. But eventually I did! It looked grey and spherical and got darker away from the center. It was so beautiful... I showed it to mom and she said it looked heavenly! 

When I later fired up Stellarium, I slowly realized that what I saw was not in the Andromeda constellation at all! I could not explain it. The object turned out to be in the constellation Perseus, because I recognized the stars around the object. But Stellarium showed nothing where the object was supposed to be! Finally, I realized that it was the comet I read about in astronomy blogs that had suddenly and mysteriously brightened by a factor of almost a million (the comet was at mag ~3 when I saw it). I was so happy I saw a comet, that too just a few weeks after I bought my first telescope! 

More about it here: http://en.wikipedia.org/wiki/Comet_Holmes

Almost everyone I have met had some story or the other they just had to share about the night they first saw the Milky Way, the time they woke up early and saw dozens of shooting stars, the first time they ever looked through a telescope...which was your most beautiful experience in astronomy?