### #FaveAstroPlot : Exoplanet transits

I won't be as verbose this time but it's still something that I find just as interesting. The in thing about astronomy at the moment is exoplanets. Everyone talks about them, everyone wants to know if there's another planet out there like earth and EVERYONE wants to know if there is alien life somewhere else in this universe. What I find more interesting is the science behind how exoplanets are found and characterized.

This is a tweet by Phil Plait of Bad Astronomy fame (if you don't already follow him on twitter, you definitely should!). It is a plot of intensity or brightness of a central star as a function of time. As mentioned on the x-axis, over the course of ~4 hours, the brightness of a star fell to 0.985 times it's prior brightness and then went back to normal. This dip in brightness is because this star is being eclipsed by a planet that is revolving around it (and luckily, in the plane of sight!). Astronomers were able to distinguish this drop of intensity with other types of drops in intensity such as when a star's brightness intrinsically varies periodically.

Note the fact that the star's brightness fell to 0.985 times that of it's normal brightness due to the exoplanet transit. I'd like to calculate by how much normal tube lights flicker to put this number in context. Such extremely precise photometry is what's needed to discover exoplanets.

Again, the source for these bunch of posts comes from here in case you want to see more such awesome plots.

### Animation using GNUPlot

Animation using GNUPlotI've been trying to create an animation depicting a quasar spectrum moving across the 5 SDSS pass bands with respect to redshift. It is important to visualise what emission lines are moving in and out of bands to be able to understand the color-redshift plots and the changes in it.
I've tried doing this using the animate function in matplotlib, python but i wasn't able to make it work - meaning i worked on it for a couple of days and then i gave up, not having found solutions for my problems on the internet.
And then i came across this site, where the gunn-peterson trough and the lyman alpha forest have been depicted - in a beautiful manner. And this got me interested in using js and d3 to do the animations and make it dynamic - using sliders etc.
In the meanwhile, i thought i'd look up and see if there was a way to create animations in gnuplot and whoopdedoo, what do i find but nirvana!

In the image, you see 5 static curves and one dynam…

### on MOOCs.

For those of you who don't know, MOOC stands for Massively Open Online Course.

The internet is an awesome thing. It's making education free for all. Well, mostly free. But it's surprising at the width and depth of courses being offered online. And it looks like they are also having an impact on students, especially those from universities that are not top ranked. Students in all parts of the world can now get a first class education experience, thanks to courses offered by Stanford, MIT, Caltech, etc.

I'm talking about MOOCs because one of my new year resolutions is to take online courses, atleast 2 per semester (6 months). And I've chosen the following two courses on edX - Analyzing Big Data with Microsoft R Server and Data Science Essentials for now. I looked at courses on Coursera but I couldn't find any which was worthy and free. There are a lot more MOOC providers out there but let's start here. And I feel like the two courses are relevant to where I …