Skip to main content

#FaveAstroPlot : Pulsars

Here's a tweet showing the radio pulses observed from a pulsar, in fact the first radio pulsar discovered by Jocelyn Bell Burnell, for which her thesis adviser got a Nobel prize (which he didn't share with her but that's a whole different story). There's also a fairly interesting story behind the image itself that can be found here.

Firstly, put yourself in a time and age when radio astronomy was still nascent and people were just scratching the surface of various radio sources. Also, this wasn't the era of milli-arcsecond resolution radio astronomy but it was the era of single dish-arcminute resolution astronomy. Radio astronomers used to perform lunar occultations to reduce the uncertainty of an astronomical object's position. Secondly, this was before digital devices were ubiquitous for recording and displaying the radio signals. There were analog chart recorders which used to plot the total strength of the radio signal that the telescope receives on ginormous pieces of chart paper (an example can be found here).

Jocelyn Bell Burnell, then a graduate student, was performing some radio observations when she noticed regularly spaced peaks in her signal. of extraterrestrial origin and without precedent, the student-guide team chose to not publish the data but to perform more observations in hopes of either disproving the previous observation as man made noise or prove that there were more such radio astronomical objects. Well, the rest is history and pulsars are a really interesting part of radio astronomy and astrophysics in general. They are also used to test the general theory of relativity but we'll get to that in a later part.

Popular posts from this blog

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 …

Pandas download statistics, PyPI and Google BigQuery - Daily downloads and downloads by latest version

Inspired by this blog post :, I wanted to play around with Google BigQuery myself. And the blog post is pretty awesome because it has sample queries. I mix and matched the examples mentioned on the blog post, intent on answering two questions - 
1. How many people download the Pandas library on a daily basis? Actually, if you think about it, it's more of a question of how many times was the pandas library downloaded in a single day, because the same person could've downloaded multiple times. Or a bot could've.
This was just a fun first query/question.
2. What is the adoption rate of different versions of the Pandas library? You might have come across similar graphs which show the adoption rate of various versions of Windows.
Answering this question is actually important because the developers should have an idea of what the most popular versions are, see whether or not users are adopting new features/changes they provide…