Original URL: http://www.theregister.co.uk/2010/08/20/paris_scope/

PARIS acquires visual tracking capability

Sets telescopic sights on Vulture 1

By Lester Haines

Posted in SPB, 20th August 2010 13:22 GMT

Our Paper Aircraft Released Into Space (PARIS) programme continues to advance on multiple fronts, with the Vulture 1-X structure coming along nicely, a Mark 2 release mechanism ready for testing and our logistics team pondering just how to get the maximum bangs for bucks from launch day - when it finally arrives.

As avid followers of PARIS know, our main payload will be packing a Kodak Zx1 video camera, which we hope will capture the Vulture 1 release and thereafter some nice footage of our beloved home planet.

What we hadn't thought about, though, was the possibility of filming the ascent and release from the ground. That was until an astronomer pal of El Reg's Iberian bureau, Alejandro Díaz, suggested we deploy his vast array of telescopes and binoculars for the job.

The target - A4 sheet of orange card marked with pink fluorescent paintWell, we like a bit of gauntlet throwing, so we challenged Alejandro to spot and photograph an A4 target (pictured) from a distance of 20km+. After a bit of mulling, we found a good spot to set up the kit, and a suitable location to place our objective.

The former is the Puerto de Tornavacas (.kmz here) on the border between Castilla y León and Extremadura; the latter a road junction 23km down the Jerte valley (.kmz here):

Google Earth grab showing viewing point and target for telescope test

This is the view from the target location, with the Puerto de Tornavacas indicated...

The target location, with the telescope position arrowed

...and here you have the view from there, with the target location nailed by the big red arrow:

The view down the valley from Puerto de Tornavacas, with target location arrowed

The target attached to some big drainage pipesSo, we nipped down the valley and slapped our target on some drainage pipes which had been conveniently dumped at the road junction.

Back up at the Puerto de Tornavacas, though, Alejandro's first attempt to grab the objective with a selection of binoculars made us realise we were going to need more grunt.

The reasoning behind using a pair of binoculars was that we could attach a video camera to one eyepiece, and give it plenty of zoom, while using the other eyepiece - with a wider angle of field - to track the balloon, main payload and Vulture 1 visually.

Alejandro and his mighty 'scopeThat was a non-starter, though, so cue Alejandro and his mighty Clear Vue 101 'scope (pictured) with which we were finally able to get a result.

There are a couple of things you have to bear in mind here. Atmospheric conditions were far from ideal for our test, with heat haze obscuring the view and a brisk breeze buffeting the telescope. There's a lot more dense air in a horizontal line of sight than when you're staring 20km straight up, and Vulture 1 and our meteorological balloon will also be much easier to spot against a crisp blue sky.

It has to be said, capturing an A4 sheet of cardboard from 23,000 metres was a big ask, but it's hats off to Alejandro for this view:

The target seen from 23km

We're going to keep working to refine our visual tracking capability, and will post some video of a moving target in due course. ®

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