Skip to main content

Sifting through photographs : The comet 17P/Holmes' orbit from images on the WWW

I watched this video a long long time ago, where Dr. David W. Hogg using images publicly available on the internet to do science. Case in point is this paper they published where they tried understanding the trajectory of the comet 17P/Holmes from astrophotographers' images online. They searched for images of the comet, after it brightened and public interest in it had gone up. They then tagged the images to know what part of the sky they were looking at using They then did some math, which I will hopefully understand one day, to weigh different images depending on their authenticity and how their metadata of when the images were taken was compared with their predictions of when the comet was in the field of view of the picture. One day. They were, in fact, finally able to reconstruct the orbit of the comet, albeit a slight error.

The video mentioned above gives more examples of such, including one awesome example where they rediscover stellar tidal streams observed using dedicated telescopes and instruments by searching for and stacking properly (there's a bit of math there as well) images available on the internet. The interesting comparison they draw in the paper is that this is citizen science but the citizens aren't volunteering their manpower, in fact they might not even have this purpose in mind when they take the picture.

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…