## Posts

Showing posts from 2012

### 10,000 views.

Well, i've finally cracked 10,000 views. With around ~12 page views a day on an average last month, when i didn't post anything for weeks together and stopped posting links on fb, i barely crossed this line at a snail's pace. All of this after i started seriously blogging in june with ~5-6 blog posts a month.

This has been an interesting time for me, i've had something constant in my life for about 6 months now. And now to crank it up a notch. I have a couple of plans for this blog and you'll see how things roll starting Jan 15th.

Let's see how long it takes for me to crack the next 10,000 Page views.
Thanks and Cheers,
Rahul...

### How to pursue Radio Astronomy

If you are a complete noob, Radio Astronomy deals with the study of emissions in the radio wave part of the electromagnetic spectrum i.e ~10 MHz to 10 GHz. The emissions might be from the sun, inter-planetary i.e from other planets in the solar system, extra-solar, galactic or extra-galactic in nature. It also deals with the mechanism behind the emission of energy in this spectrum. Various process contribute to emissions from astronomical sources, synchrotron emission causing some of the stronger emissions.

I've already written a lot about what i've done in radio astronomy, the radio jove project that i've worked on, doubts i had regarding the project, the observable range in radio astronomyandbuilding a radio telescope. I also implemented a different method of data acquisition (different from the method used in radio jove) about which i've written here

Now, i thought it'd be better if i just s…

### Installing Linux

As another one of my friends who was trying to install a linux OS asked me how to go about doing it, i decided to write this article.

One of the major hurdles in a installing linux OS is to decide which type of linux OS to install -
The more commonly known Ubuntuthe more serious Fedoraor the bare bonesDebian. I don't guess many of you know aboutArch Linuxand if you are a noob to linux, i suggest you stay away from it. You can only start dreaming about it after using a linux OS for atleast ~2 months! There are quite a few lesser known versions of linux OS like gentoo linux and then there are enterprise linux OS like CentOS, Red hat linux and so on and so forth.

As far as i know, if you just want to try out a linux OS, if you do not intend to do any serious work on linux, Ubuntu is one of the best versions of linux OS to install. Almost everyone starts out as an ubuntu user or atleast that's what i think.

Well, after you've decided the linux OS you want to install, you can…

### Winter School on Astronomy and Astrophysics at IIST, Trivandrum

The title pretty much sums up one of the reasons why this blog has been deserted for ~3 weeks. Well atleast there aren't tumble weeds blowing across yet. I will not let the situation get that bad. Anyway, coming back to the point, i had my semester exams from the 19th november and a couple of lab exams before that. And on the day of my final exam - 29th november, i had to catch a train to trivandrum at 7:45PM. Luckily enough the exam got shifted to the morning (9-12 AM) instead of the afternoon (2-5 PM) and i was able to escape chennai.

The reason why i am going to trivandrum (currently am) is for a winter school on astronomy and astrophysics at IIST, Trivandrum. For those of you who don't know what a winter school is, it is a 10 day fast track course to introduce students to a certain area of science, in this case astronomy and astrophysics. I haven't personally taken any course on astronomy or astrophysics and i've been wondering what we'll be taught since i got …

### Editing Lengthy Texts and Notes.

I am currently working on an assignment where the students in my class are expected to go through a book and make a list of all the errors we can find in the book. Well, to be fair, it's actually 10 chapters of a book and ~20 pages on an average per chapter. Well, the lazy engineering students that we are, we formed a group and divided work/chapters among ourselves so that none of us will have to read the whole thing but all of us get full credit. BTW, this is for a humanities course titled 'Environmental and Resource Economics' and the textbook we are expected to go through is called 'Energy and the Wealth of Nations'.

And in this process, i came upon one interesting question.

As i was reading the chapters, i noticed how hard it was for me to keep track of the errata.
As it is a book, the whole thing is written in chapters and pages and if i do find a mistake, i'd have to note down the # of the page, the paragraph in the page and the sentence in that particular p…

### Using MathJax to write equations on blogs

So i just installed mathjax and i want to check it out and see if it works $x^n + x_n = 5$
and $$a*b*c = x^a + y^b$$

And it works!
So, MathJax is a java script which can be used to write beautiful equations using TeX on websites. Read this blog post for the installation process. Apparently there are two ways of going about it.
One is to install MathJax on the server where your website is hosted.
The other, especially in the case of blogs, is to add a certain script to the html template of the blog.  The setup instructions for a blogger site have been mentioned and i'm sure the parallels on WordPress and Tumblr can be figured out without much trouble.

Using this in the coming blogposts should be fun :D

### Learning Latek

I've been trying to learn LaTeX for a while now but learning it from scratch without a template is very very hard. Especially for a person who insists on going through atleast a couple of manuals before he goes hands-on (that's me btw).

I've finally been able to get a grip on writing documents in LaTeX because i've been writing something in TeX for a while now. And i know quite a few people who are putting off using LaTeX for the same reason that i did. So, i thought that if i could write a good template which would encompass every basic functionality necessary for a student to write a report, i thought it'd help in getting people to start working on LaTeX.

So, here's what i've been able to come up with in one afternoon...

% each of these can be considered as commands and each command has different outputs depending on arguments which are given in {}. Look for the different arguments each of these functions have. some have one. quite a few have many.

\docume…

### I wish i were a machine

Well firstly, let me tell that you i've been trying to write atleast twice a week for the last 4 months. It was one of the few things in my life that i was trying to do on schedule. Granted, i wasn't always able to get 8 posts a month but i've been able to squeeze 6/7 out on an average.
Now, coming to the point, i haven't been able to do the same for the last 2 weeks. For one, i was sick for most of the last 2 weeks. And on top of that, i've been going through a strange patch in my life and my mind is being constantly bombarded by thoughts, ideas and what not. I've thought, more than once in the last two weeks, of making a pill/machine that will help a person completely shut down their mind; no thoughts while you lay on your bed; no dreams; nothing. I haven't been productive at all; missing classes, falling behind on assignments, i kept wondering how it would be if i were a machine.

Seriously, what if i were a machine instead of a human.

### Interesting arXiv papers for the week

I thought i'd start something new this week.
I shall start reading and understanding atleast 5 papers from this week on.

While i was doing this in the 2010 summer as well, i couldn't understand most of the papers. I was just looking for interesting facts or snippets of awesomeness in the papers. Now that i've reached a position in my academic career where i can't keep brushing over the details, i thought this would be a good way to keep working on problems and understand new topics.

So, the papers for this week are -

Multi-Band Feeds: A Design Study - is a paper on the antenna architectures. There are certain types of antennae known a Log-Periodic Antenna or Eleven Feed antenna which have a broad observing bandwidth. Though a broad observing bandwidth is a good thing, RF Interference will dwarf the astronomical signal in certain parts of the band!

Inorder to avoid this, a new antenna architecture has been designed, simulated and implemented which has the capability to …

### Energy from the Stars : The ElectroMagnetic Spectrum

This is second in a series of articles on the basics of astronomy and observational techniques. you can read the first article here. The articles will broadly cover the different kinds of telescopes used for the different energetic phenomenon associated with astronomy. In the previous article, the reader was hinted at the possibility of observations being carried out outside the visible spectrum using specific instruments. In this article, i will describe the different energy levels observed in astronomy and their associated phenomenon. I will mention the new telescopes which are observing emissions in these exotic bands and leave you to read further.

ElectroMagnetic Spectrum - as we all know, the electromagnetic spectrum can be roughly divided up into -
Gamma Rays X Rays UV rays Visible Light IR rays Microwave radiation Radio wavesthis should help you better recollect the frequencies and wavelengths of the corresponding waves and also get an idea of the respected energies involved wi…

### Finally, we're getting somewhere.

So, i finally met the professor whom i've been stalking for almost 3 weeks now! I kept mailing the prof and swinging by his room, hoping that he'd be there. And last wednesday, i finally met him, Prof. HSR, a professor in the Elec Dept at IIT Madras. He's known to be a pundit on antenna design and simulations. When i started working on the radio astronomy project, as senior had asked me to contact him regarding any doubts and more fundamentally, the direction in which my project would head.

well, now that i've finally met him, i did get quite a few doubts cleared and know what i'm supposed to be doing in the coming months!

Apparently, as i suspected, the response function of the antenna or the gain from the antenna is frequency dependent and trying to deconvolute the signal (in the frequency spectrum) from the antenna without the proper response function is moot!

Also, in addition to the response function, the effective aperture of the antenna is also frequency dep…

### Experiments with Z moon

A couple of days back, we were really bored and we just got up and moved to the rooftop of the physics dept to try do some astro-photography.

and here's what came of it -

they are all pics of the same moon on the same night.
the difference is the camera settings - The ISO and shutter speed.
from what we realized, we suggest that you guys use

ISO 100 at 1/30,1/60;
ISO 200 at 1/60, 1/100;
ISO 400 at 1/250, 1/600 and even 1/1000.

The DSLR we used was a Canon 550D.

ps - you need a telescope along with the usual camera to be able to take such pictures.

### Radio Astronomy - The Observable Range

A really important hurdle to clear in the process of radio astronomy is to decide on a frequency band to listen to and this is not a trivial process. because there is quite a bit of terrestrial communication(comm) signal and extra-terrestrial satellite comm. signals, we can't just build a antenna at any frequency and expect to be able to see extra-galactic radio signals.

This was one of the things i was having a hard time figuring out because there apparently are quite a few bands where we have less comm. noise but no explicit information on the spectrum allocation and the bands alloted specifically for radio astronomy.

I browsed through pages finding partial answers like this one, which is relevant to australia and gives a brief outline of the bands where one can try observe using a radio telescope without having to worry about comm noise.

but that still wasnt satisfactory because i wanted to look at the indian scenario.
and then i struck gold. The National Frequency Allocation P…

### The most awesome list of Sci-Fi movies I've found. Ever.

So, it was just another weekend and i was abusing the 24 hour net connection we have on the weekend and surfing through the web, reading random articles from io9, engadget and arstechnica when i came upon this awesome collection. this is the list of all the movies that the authors took as case studies in writing the booj "Make It So : Design Lessons From SciFi".

2001: A Space Odyssey Adaptive Path CharmrAeon FluxAesthedesAI - seen itAlien - seen itAlien Resurrection Alien vs. Predator - seen itApple Project 2000ArmageddonAvatar - obviously, seen it. Back to the Future - watch all 3 every month! BarbarellaBatman - seen all of them and dream about being batman. Battlestar Gallactica Big Bang Theory - see every new episode and waiting for the new season Blade Runner BrainstormBrazilBuck Rogers (1939)Children of MenChronicles Of Riddick - seen it ChrysalisCisco TelepresenceCity of Lost ChildrenClockwork Orange - seen it Cowboy Bebop - seen it, it's an anime btw and one of th…

### Webpage 1.2

As i mentioned in the past, i was learning HTML and CSS3 to be able to write code for my own website and partially to see how hard it is to learn coding in HTML. And it's been an awesome experience!

I've put in hardly 15 Hrs into the whole thing and i now have a fairly good-looking webpage v1.2, a fairly good looking update from v1.1 of the page which doesnt have the CSS3 styling hints to it. Though i havent mastered the language yet, i am getting good at it. who knows, maybe one day i might want to be a Web-Ops co-ordinator for my college's technical festival.

but right now, the only thing on my mind is to get a place on my department's or my college's server to host this webpage on it. as i've mentioned, linking a webpage about yourselves would be an easier way to contact profs than writing huge mails and resumes.

There's one other thing that i dont understand.
There are a lot of web operations coordinators who are free for the whole of the year after sh…