Re: Heavens-Above goes mobile

From: via Seesat-l <>
Date: 19 Jun 2014 07:41:35 -0700
It looks good! And for anyone who hasn't realized, you can use this "mobile" version in any modern web browser, mobile or desktop. Visit here:, input your lat and lon if the app can't acquire them from your browser, and you're all set.

I've been playing with the mobile site for the past hour (since the right after your announcement). I can imagine lots of enhancements, but the current functionality is terrific. One thing that I could see being very useful would be a time offset. When I selected my current location, in the live map it showed that I would have a pass in 11 hours and 22 minutes. For testing purposes, I moved to a different location on the globe that was in twilight to see some visible passes, but it would be nice to be able to jump ahead to evening twilight for my location and see how things look. And if we're going to be jumping around in time, some means to accelerate/decelerate the passage of time and pause would be useful. Also, I would prefer a smaller moving icon on the satellite --a slightly pulsating, bright dot would be nice. I realize there's probably a wish-list a mile long already for new features ...just throwing out the first ideas that popped into my head.

There's one potential gotcha in this HTML5 version. On my laptop, CPU usage climbs to about 50% with three satellites displayed, and the fan turns on. On a mobile device, this will drain the battery rapidly. How frequently are you updating the canvas? Anything faster than 30 fps is un-necessary, right? Maybe you could also consider a slow updates mode: once per second, for example. I realize that the animation would be less attractive, but until browsers start using hardware graphics processors for the HTML5 canvas, JS animation is done in software and keeps the CPU very busy.

Frank Reed
Conanicut Island USA

PS: Have a look at "Node Webkit" if you haven't seen it yet. You can build stand-alone Windows/Mac/Linux desktop apps very easily from HTML5 code like this.

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Received on Thu Jun 19 2014 - 09:43:35 UTC

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