Virtual Sky 0.3.8

I wanted to share a quick update on Virtual Sky. I created it as part of my work at LCOGT where it was, initially, an experiment in using some of the latest web techniques (HTML5 canvas). However it became clear that, as well as being useful for parts of the LCOGT website, it could allow others to embed a view of the night sky in their webpages too. I like it when I can make things that are useful.

This week I released a couple of updates to Virtual Sky. The updates should have solved some issues with older versions of Internet Explorer (7 & 8), fixed issues if the part of a page containing Virtual Sky gets re-sized, and reduced the load time slightly. If you embed Virtual Sky on your website, these updates are already live so you don't need to do anything.

The updates

Being a demanding user of your own service can really help to make it better. Recently I've been working on an observation scheduling interface for LCOGT and wanted to use Virtual Sky as part of that. We took a decision that the scheduling interface should be able to adapt to different widths and that meant Virtual Sky had to be able to shrink and grow to different sizes too. After a small matter of coding, Virtual Sky should now cope with being re-sized.

A few months ago someone reported some bugs in Internet Explorer 7 & 8 and I've spent quite a while battling with each of them. I think I've mostly won that battle although IE 8 still has issues with dragging the sky that I haven't been able to fix.

Finally, I wanted to reduce the load time. The simplest way to do that was to reduce the file size. It turned out that approximately half the file was taken up by the data defining the stars. As there are many times more fainter stars than bright stars, and the faint stars are less obvious, I realised that I could display the bright stars initially and add in the fainter stars a little later. The result is a shorter time before something is displayed. This, along with some minification, has reduced the main file from 112 kB down to 78 kB (with a delayed 25 kB for the faint stars).

I've tested these updates in IE 7/8/9, Safari 5.1.2, Firefox 8/10/11/Mobile beta, Android 2.2 browser, and Opera 11.61. The growing number of browser versions makes it difficult to test everything so if you spot any bugs please let me know the details along with your web browser name and version.

Posted in astro blog by Stuart on Saturday 10th Mar 2012 (01:45 GMT) | Permalink
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