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  • Prasanna 5:14 pm on February 10, 2010 Permalink | Reply  

    Cleaning the telescope 

    How to clean a dirty telescope :ο»Ώ

    Step 1
    Take out the dirty mirror

    Step 2
    Take the mirror out of it’s mount

    Step 3
    Use a hair dryer to blow off sand-like dust particles. Keep the heat setting in the hairdryer at the minimum.

    Step 4
    Find a nice big bowl like this and clean it.

    Step 5

    Place the mirror gently inside the bowl and pour enough distilled water so that the mirror is completely immersed.

    Step 6

    Add some Dazzl. This gets rid of the fungus on the mirror

    Step 7

    Rub the surface of the mirror very gently with clean hands, all the time making sure that the mirror is totally immersed.

    Step 8

    Rub the surface of the mirror very gently with cotton, all the time making sure that the mirror is totally immersed.

    Step 9

    Take the mirror out of water and using a stream of water, clean off the particles that are still stuck to the surface.

    Step 10

    Take the mirror out of the bowl and dry it using a hairdryer.

    Step 11

    Look at the clean mirror and be happy

    Step 12

    Clean the secondary mirror using the same technique (with a stream of water)

    Step 13

    Dry the secondary mirror using a hairdryer.

    Step 14

    Before mounting the mirrors, clean the tube of the telescope the traditional way.

    Step 15

    Collimate the mirror assembely.

    There , we have a much cleaner and better telescope.

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  • Prasanna 9:19 pm on January 28, 2010 Permalink | Reply  

    Annular Solar Eclipse at Rameswaram 

    It all started off sometime in 2008, when we discovered that there will be an annular eclipse in Jan 2010 that doesn’t require too much of travelling. We had initially planned to observe from Madurai. Later plans changed and the want of being closer to the central line of the eclipse, took us to Rameswaram.

    We conveniently forgot about the eclipse until November 2009 when we realised that the train tickets were already running into waiting list! Immediately, we initiated the whole planning procedure, which started off with a Google Spreadsheet where interested persons signed up for the trip. Towards the end of November, Akarsh and me booked tickets for the 40 odd people who had signed up. Since we were sort of late, our seats were scattered all along the length of the train, with at least a few of us in every compartment.

    Back to college after the December vacation, we had around 15 days to actually plan the trip. In order to do this, Akarsh suggested that we should visit Rameswaram once beforehand. This turned out to be a really useful idea. Vinay Hegde and me visited Rameswaram onΒ  the weekend before the eclipse. We started from Chennai on Friday night, and after a 12 hour overnight bus journey, reached Ramnad the next morning. Our first item on the priority list was to get some accommodation for the huge group. We spent the whole morning on this, but in vain. Due to thai amavAsai, there was virtually no place to stay anywhere in Rameswaram. We informed Akarsh about this who was back home in IITM, and he decided to do something about this while we went on the next item – finding an observation site. We had ruled out any area near the Rameswaram temple or Dhanushkodi because of the scary stories we heard from the locals about huge crowds and stampedes. But we wanted to stay on the island, otherwise we would be losing out on precious annularity time. We took a bus to Pamban (west coast of the island) and started surveying the beaches there. We found them to be extremely dirty.

    We came across the local police station and decided to go in and ask for help. The inspector in the station suggested Vivekananda Mani Mandapam. We took an auto rickshaw to the place and immediately fell in love with it. The Mani Mandapam was away from all human habitation, very clean and extremely silent. And the beaches behind the Mandapam were simply beautiful. We talked to Mr. Radhakrishnan, the care taker of the place, who was very receptive to the idea of a group from Chennai coming down there to observe the eclipse.

    So, Observation site – Check. It was around 3 pm and we hadn’t had lunch. But we had absolutely no time to lose. Meanwhile, Akarsh had spoken to his dad, who with the help of his friend, directed us to Aruna Stores in Ramnad. We caught the next bus to Ramnad, and reached Aruna Stores by 4 pm. With their help, we booked accommodation for all the 40 of us in Jodhi Lodge. The owner took us to an “Iyengar” Hotel nearby and showed us around his book store.Β  He seemed to be very proud of the fact that Dr. Abdul Kalam used to buy books from this store. πŸ™‚

    Accommodation – Check. It was 6:30 pm. We still had some time to catch the train. We decided to look out for local travel options. We found a street with lots of vans. We approached one of the drivers. He agreed to arrange for two vans to pick us up from the Railway station and take us to the observation site. This completed our Things to do for the day. We had a satisfactory dinner and waited for the train to arrive. On – site planning – Check.

    Back home, we had lots of things to get ready – telescope projection setup and get various letters signed by various people. With great help from Vinay, Akshay, Smruthi, Naveen (even though he was not coming to Ramseswaram) and a few others, we got all this done. The projection setup for the telescope was inspired by this. The raw materials used for this – A dustbin, a PVC pipe and some butter paper! It was really interesting to drill holes through the dustbin using focused sunlight through the telescope!

    Two days before we left, we convened a meeting to decide on our itinerary and to brief everyone about various issues involved with the trip. On 14th Jan 2010, we were off !

    We had an ‘attendance sheet’ with us and to make sure that everyone was on the train, Vinay and me did a quick run along the length of the train two minutes before the departure to make sure everyone was inside. I enjoyed this!

    We reached Ramnad at around 8 AM on 15th Jan, and as promised, found two vans waiting for us outside the Railway station. The skies were totally cloudy, but Akarsh reassured us that it would clear up by noon. We went to the lodge, quickly freshened ourselves up and left for Pamban. We were stopped just before Pamban Bridge in order to allow the Tamil Nadu Governor to get into Rameswaram, who was apparently getting there to watch the eclipse himself. Fortunately, the wait ended in just around 20 mins and we continued towards Pamban.

    All of us enjoyed clicking the amazing view from the Pamban bridge!

    We reached the observation site around 11:15 am. I could never forget the chorus ‘wow’ as we approached the Vivekanandar Manimandapam. It was indeed a beautiful place.

    By the time we arrived at the place, the partial phase of the eclipse had already started. We quickly set up all our instruments and started observing. Our dustbin – butter paper projection system was a great hit!

    Photo Credit :Β  Rahul Poruri

    We patiently observed the entire (almost) length of the eclipse. There were absolutely no clouds anywhere during the eclipse! Highlights of the show were Bailey’s Beads and the eclipse tree. Again, I can’t forget the collective Wow during the Bailey’s Beads. Below is a photo from Siddheshwar Patri.

    We also had fun with pinhole projections and the eclipse tree under which we could see uncountable eclipsed suns!

    Photo Credit :Β  Rahul Poruri

    Here are my versions of the entire eclipse sequence.

    Lots of local people enjoyed watching the eclipse with us. I particularly liked this photo πŸ™‚

    Photo Credit : Akarsh Simha

    After the eclipse was over, a part of the crowd from IITM jumped into the water, unable to resist the temptation offered by very clean waters.

    Some of us were really hungry. We decided to leave the people in the water alone and go in search of food. It was too late (3 pm) for lunch. So we had to make do with cakes and tea at a bakery. The tea was exceptionally good. We came back to our Manimandapam to pick up the ones in the water and head to Ramnad to fill our stomachs. There were plans of overnight observation from the Manimandapam. Moreover, I had to attend a telephonic interview. So I chose to stay back with the telescope and attend the interview while others went off to Ramnad. I was really pleased when Sivaraman, Smruthi, Sathish and Rahul volunteered to stay back with me πŸ™‚ . I was very happy after my interview and already began to feel really satisfied with the trip. Till the others returned, we decided to have fun with some photos to forget our hunger. This particular photo generated a lot of LOLs (@ Sathish) πŸ˜€

    As it turned dark, we sat on the beach with mouths wide open looking at the sky. The sky was simply amazing! Unwilling to stay put, we started taking fixed tripod photos until others arrived.

    Around 8:30 PM, Akarsh and Akshay arrived. More importantly, they got us food! While we gorged, Akarsh and Akshay set up the telescope on the beach. We observed the Orion Nebula, some open and globular clusters. But the highlight of the night was most definitely the Large Magellanic Cloud. Being extremely South in the sky, it is very difficult to observe from the Northern Hemisphere. But we took advantage of the latitude of the place (9 deg N) and seas towards the southern direction. Many of us were able to see it naked eye. I took a photo of it to help confirm the naked eye observation.

    We had a great night of observation with intermittent naps. Next day morning, we got up, took some groups photos on the beach and left for Ramnad

    The next day, 16th Jan, all of us split up and went our own ways. One group went to Dhanushkodi (Tip of Rameshwaram Island, stone’s throw from Sri Lanka). Since there’s no proper road to the place, they had to travel in weird vehicles.I’m guessing they had a lot of fun!

    Photo Credit :Β  Rahul Poruri

    Another group went into the Rameswaram Temple. Sathish, Smruthi and me left towards Karaikkudi to attempt our first confluence visit (10 N, 79 E). Blog post about that later. We boarded the train really late into the night at Trichy almost half way from Ramnad to Chennai! We reached Chennai next morning. Here’s a pic taken at Chennai Egmore after we got down. This was one trip that I’ll never forget! Everything just worked fine, and I really had the satisfaction of having helped organise something not so trivial and succeeded!

    Photo Credit : Akarsh Simha
    • Vimal 2:45 am on January 29, 2010 Permalink | Reply

      nice da! i wish i was there.. 😦 it was interesting to see the locals also enjoying the eclipse along with you guys. and yes, did you guys put fundaes to them as well? πŸ™‚

    • Rakesh Misra 6:56 pm on January 29, 2010 Permalink | Reply

      Awesome! Hats off to your patience and enthusiasm to put together this article!

    • Subha Ravi 1:53 pm on February 23, 2010 Permalink | Reply

      Attaboy! Now I know why you had to go twice over to Rameswaram-at the cost of Mr.Jeromes’s classes?ha ha,great job! i could actually visualise the fun and learning there.May your tribe increase1 Good luck
      S Ravi

    • Enoch 6:28 pm on September 24, 2010 Permalink | Reply

      It is really great to know about a outsider’s view of my beautiful hometown. I’m a native of Rameswaram and brought up in Karaikudi; the two places which you had visited… btw .. what is your major in IIT-M ?

    • Rajasekhar 2:24 pm on December 21, 2010 Permalink | Reply

      It’s very nice to find this link and Snaps, reviewing the moments of the complete eclipse event, I have joined BAS group just after Pamban bridge before heading to Vivekanandar Mantapam in the Cab, hospitality of the group administration is very Good, especially the availability of solar filters have been of great help in clicking few snaps.

  • Prasanna 9:03 am on July 12, 2008 Permalink | Reply
    Tags: beach, sunrise, time lapse   

    Sunrise .. 

    Time lapse videos seem to be my latest addiction. Here’s one video of a Sunrise taken today from Elliots Beach.

    Couple of photos from today’s early morning walk can be found at http://caughtonlens.wordpress.com/

    • Vikram S V 10:22 am on July 12, 2008 Permalink | Reply

      That was very beautiful video! It would have been much better if only there were fewer clouds. I also think you can make the video play at a little lower value of fps.

    • naveen 11:01 am on July 12, 2008 Permalink | Reply

      This is the most amazing video I’ve ever seen πŸ™‚
      I always wanted to see sunrise on the beach… Thanks πŸ™‚
      Good work.

    • Prasanna 11:25 am on July 12, 2008 Permalink | Reply

      Thanks. I can’t reduce the FPS further because its already at 8fps
      which is too slow. Problem is that I did not take enough shots. Will
      try that next time

      Thanks. And you can try searching for Sunrise Time Lapse videos on
      Youtube. Some of them are really good.

    • Akila 12:52 pm on July 12, 2008 Permalink | Reply

      It is very nice that you find time for the little experiments that make life so beautiful πŸ™‚

    • Prasanna 4:26 pm on July 12, 2008 Permalink | Reply


    • Akarsh 11:40 pm on July 13, 2008 Permalink | Reply


    • prakash 7:31 pm on July 20, 2008 Permalink | Reply

      Great video, really nice to see a sunrise video πŸ™‚

    • Vinay 12:27 am on July 30, 2008 Permalink | Reply

      Good work!
      Its always nice to see the sunrise… I agree that taking a few more shots would make it even more appealing πŸ™‚

    • prashant 3:11 am on December 16, 2008 Permalink | Reply

      Awesome!!! will love to see your timelapse videos of saarang πŸ™‚

    • rimifooma 8:38 pm on December 9, 2009 Permalink | Reply

      Wow, I didn’t heard about this topic up to the present. Thanx.

  • Prasanna 8:03 pm on July 11, 2008 Permalink | Reply  

    My First Time-Lapse Video 

    I came to know about CHDK recently, which has given my Canon Powershot A540 a complete makeover. I decided to try out a time-lapse video which resulted in this:

    • Infy 3:46 am on July 13, 2008 Permalink | Reply

      Nice video πŸ™‚

      And, a great find with CHDK. It’s amazing. Imagine shooting in RAW with a cam in the powershot series, extending exposures to 65s. Thanks πŸ™‚ It’ll be the first thing I’ll be looking into tomorrow.

    • tdmphotography 10:20 pm on September 12, 2008 Permalink | Reply

      Nice idea I keep meaning to try this. Will probs be easier with a DSLR too. Thanks for inspiration.

  • Prasanna 8:45 pm on July 9, 2008 Permalink | Reply
    Tags: beginning, blog, photo   

    My New Photo Blog 

    Here’s the beginning of another long journey.


    First post:


  • Prasanna 7:31 pm on July 5, 2008 Permalink | Reply
    Tags: binary, css, gif, html, image   

    Versatile CSS 

    Today, I learnt that CSS could make this:

    Out of this:


    • arunchaganty 1:14 am on July 6, 2008 Permalink | Reply

      I think that is valid for any image as well. So the much longer:

      Would show the ArchLInux logo.

    • arunchaganty 1:15 am on July 6, 2008 Permalink | Reply

      Ah, WordPress didn’t accept it. Here:
      I think that is valid for any image as well. So the much longer:

      Would show the ArchLInux logo.

    • arunchaganty 1:16 am on July 6, 2008 Permalink | Reply

      I’m sorry for cupping so many times.
      Delete my old failures.

  • Prasanna 5:48 pm on July 5, 2008 Permalink | Reply
    Tags: convert, ffmpeg, format, ipod, mobile, movie, nokia, video   

    Movies for Mobile Phones / iPods 

    Want to watch your favourite movies on your iPod or mobile phone ? (Great for long journeys) And are you a Linux user ? Read on.

    (Windows / Mac users might as well use the software that comes with the mobile phone / iPod)

    Most of the phones / iPods play videos in MPEG – 4 format and sounds in AAC format. So, all we we need to do is to convert a video into MPEG – 4 with sound encoded as AAC.

    Step 1: Get ffmpeg code

    According to the ffmpeg project website, “SVN snapshots work really well 99% of the time so people are not afraid to use them”. So, we checkout their SVN repository

    $ svn checkout svn://svn.mplayerhq.hu/ffmpeg/trunk ffmpeg

    Step 2: Compile

    Before compiling, we need to set proper compile options.

    $ cd ffmpeg/
    $ ./configure --enable-gpl --enable-pthreads --enable-libvorbis --enable-liba52 --enable-libgsm --disable-debug --enable-shared --enable-libfaac --prefix=/usr/local

    Now, compile

    $ make
    $ sudo make install

    Step 3: Convert

    Convert the video file of your choice to the MPEG -4 / AAC format.

    $ ffpeg -i some_video.avi -s 320x240 -ab 32000 -b 64000 output.mp4

    • 320×240 is the screen size for my mobile phone (Nokia 6233) and for a standard iPod (I think)
    • -ab 32000 signifies the the output audio bitrate.(32 kbits/s)
    • -b 64000 signifies the output video bitrate (64 kbits/s)

    You can experiment with the two features above. I found these to be the ideal values, the opposing factors being quality and file size.

    You can use the following command for a Widescreen format movie. (16:9 types)

    $ ffpeg -i some_video.avi -s 320x180 -padtop 30 -padbottom 30 -ab 32000 -b 64000 output.mp4

    Suppose the audio doesn’t get encoded in AAC format by default, one can also try adding the option -acodec libfaac or -acodec aac.

    Step 4: Transfer

    Transfer the the output video to your phone / iPod and enjoy!

    • homothety 5:53 pm on July 5, 2008 Permalink | Reply

      A very nice and useful tutorial πŸ™‚

    • arunchaganty 6:23 pm on July 5, 2008 Permalink | Reply

      A question, does on have to use the svn version? Would an existing build work?

      A clarification, is it ffpeg or ffmpeg? (the cmd line tool)

      And finally, thanks! Finally, I’ll be able to put movies onto my IPod.

    • Srinidhi 11:20 pm on July 9, 2008 Permalink | Reply

      Hey, nice post. But, you can as well switch to an open source OS for your IPod. I use Rockbox on my Ipod and i don’t need to convert anything to AAC for it to work. The loading into the IPod takes very less time and very much works like a Flash memory, the OS is exactly like any distro with a lot of options. Just google it and read about it if you have the patience, MAC OS X is good, but I think this is equally good.

  • Prasanna 5:50 pm on June 24, 2008 Permalink | Reply
    Tags: chat language, formal, internet, letter   

    English Today 

    What has excessive chatting and texting done to today’s youth? This formal letter explains it all.

    Initially, I laughed at this. But now, I feel this is something serious. People should realize that such language is not ok, even if it’s all around us. Tch. Sad.

    • Naveen 6:12 pm on June 24, 2008 Permalink | Reply

      I had a hard time figuring this out: Chennai —> 6nai πŸ™‚

      This looks funny, but, as you rightly said, the laughter cannot hide the fact that the beauty of the language is being spoilt by such things…

    • Prasanna 6:39 pm on June 24, 2008 Permalink | Reply

      Someone wrote *6nai* for Chennai ?! That’s pushing it to the limits πŸ˜€

    • bharath 8:55 pm on June 24, 2008 Permalink | Reply

      did you reply to this email?

    • Srinidhi 10:56 pm on June 24, 2008 Permalink | Reply

      Well, it is very bad that people use such painful language when writing mails. The short forms are okay maybe on chat (I despise it there too), but in a formal letter like this, it is really pathetic. Well, I guess this is the state even in insti.

    • Kumar Appaiah 6:09 pm on June 27, 2008 Permalink | Reply

      i hpe u dnt us dis srt of lnguge. ts vry dfclt 2 undrstnd.

      (Basically, vowels have to be filled in the blanks, I guess.)

    • Akarsh Simha 2:24 am on July 1, 2008 Permalink | Reply

      I think the world needs a script to convert SMS lingo into proper English, and that must be incorporated into GMail, popular mail clients and major chat clients πŸ˜›

    • arunchaganty 3:52 pm on July 5, 2008 Permalink | Reply

      @Akarsh, yeah! But it would be *ver* hard to make though…

    • Leela 12:07 pm on July 11, 2008 Permalink | Reply

      It’s almost become a norm in fact to write in such preposterous language. I suppose the situation could improve if we try. For e.g., I hardly use short forms on chat now and it has caught on to at least two others I know of.

    • Prasanna 5:07 pm on July 11, 2008 Permalink | Reply

      That would only worsen the situation.

      That’s a solution …

    • Muthusubramanian NV 3:56 pm on May 17, 2009 Permalink | Reply

  • Prasanna 6:45 pm on June 23, 2008 Permalink | Reply
    Tags: chennai, , photowalk, pondy bazaar, t nagar   

    The Eighth Chennai Photowalk 

    The Eighth (first for me) Chennai Photowalk started from Panagal Park and went into Pondy Bazaar. Here are some of the shots that I took.

    Thanks to Chandru for organising the walk. I hope to be a regular photowalker from now on. It’s so much fun, you know! πŸ™‚

    All the other photos that I took during the walk, can be found in the album linked below. Do leave a comment if you like a photo. πŸ™‚

    • Sridhar 10:04 pm on June 23, 2008 Permalink | Reply

      Nice da! Didn’t know that something like this happened every year.

    • Archana 10:56 am on June 24, 2008 Permalink | Reply

      Awesome stuff! I share Sridhar’s ignorance, and am very excited about the photowalk concept πŸ™‚
      The artist’s eye is always on the lookout for the bete and the beautiful πŸ™‚

    • Prasanna 11:59 am on June 24, 2008 Permalink | Reply

      Happens every month πŸ™‚

      You can come along for the July walk if you are in Chennai at that time.

    • arunchaganty 6:08 pm on June 24, 2008 Permalink | Reply

      *Awesome* quality on those photos! You were born gifted. I especially like the old lady one. The contrast of color (you gimped it right?) is splendid.

    • Prasanna 6:41 pm on June 24, 2008 Permalink | Reply

      Thanks. And yes, I GIMPed it.

  • Prasanna 2:45 pm on June 11, 2008 Permalink | Reply
    Tags: canon, flowers, macro, powershot, wallpaper   

    Pretty Flowers 

    I guess this would be my best macro shot so far. (Click on the picture for the full size photograph ~ approx 325 KB)

    If you’d like to have this your wallpaper,

    Here’s one more shot that looks nice. (Click on the picture for the full size photograph ~ approx 301 KB)

    Again, if you’d like to have this your wallpaper,

    (Photos shot by Prasanna using Canon Powershot A540. For further exposure information, please take a look at the EXIF data)

    Some of my photos can be found here.

    • naveen 3:05 pm on June 11, 2008 Permalink | Reply


      http://iam“pro”sanna.wordpress.com would be a more appropriate address for you blog πŸ˜€

      I have the first one as my wallpaper now πŸ™‚

      Keep going!

    • Prasanna 3:10 pm on June 11, 2008 Permalink | Reply

      πŸ™‚ Thanks.

    • Ramya 2:42 pm on June 16, 2008 Permalink | Reply

      Really awesome!!

      you are becoming a professional photographer eh!?

      keep going πŸ™‚

    • Topcanon powershot 3:50 pm on May 4, 2009 Permalink | Reply

      You rock. World needs more souls like you.

    • Rohini 2:07 am on June 6, 2009 Permalink | Reply

      hey.. the ever best i hav seen in my life..:-) cheer.. great work

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