Hi all! I'm new here; I hope I am posting this in the right place and that I won't sound too ignorant! I am currently studying Electrical Engineering, and pondering "outside the box" sorts of amateur observing setups that I might be able to tinker with down the road. I am particularly interested in tracking and characterizing near earth asteroids. I am wondering, would a home-brew radar system to study NEOs be at all feasible? How powerful would such a system need to be? Has anyone built something like this? Thanks in advance for any replies!
Amateur radar astronomy?
Posted 03 December 2018 - 10:38 AM
If you look at systems like the Very Large Array in Soccoro New Mexico, or any dishes being used by Professional Astronomers which are using Radar to determine sizes of and distances to asteroids, they are rather on the large size.
But then again, where would we be if Karl Jansky hadn't started Radio Astronomy, in the 1930's I believe. So, if you think you have what it takes, not to mention the resources to build a large radio dish(es) or be like George Ellery Hale and able to talk wealthy individuals into funding your equipment and research, then go for it. Where would we be if intrepid souls didn't "boldly go" and do what others wouldn't, couldn't or were too scared to?
Good luck and God Speed.
Posted 03 December 2018 - 12:40 PM
Just a comment to ponder but I had the opportunity to play with Nike and Hawk radar systems in the 60s and 70s. Compared to today's radio astronomy dedicated systems they were relatively small arrays but by the early 80s the Japanese had reduced 40 foot trailers of equipment to foot lockers and brief cases. I suspect that there are a few hundred of these systems gathering rust and dust in some government used equipment graveyard. A little ingenuity might just re purpose this equipment to your needs without having to reinvent the wheel.
Posted 03 December 2018 - 05:14 PM
The classic textbook is Radar Astronomy by Evans and Hagfors: https://archive.org/...ronomy/page/n63
This paper addresses your question specifically: https://echo.jpl.nas...st3_ostro .pdf
Radar is allowed in the amateur radio bands but the maximum power is 1500 watts PEP. You will need a very big antenna. To start looking at amateur radar, try looking up moonbounce ham stations and see what is involved. Clearly you should start doing amateur radio astronomy and work from there. So good reading.
Posted 05 December 2018 - 11:39 AM
Not sure if it has been mentioned here, but lightcurve inversion is the cheapest, most cost-effective and fastest way of characterizing the spin state and shape of a minor body. All you need is a computerized scope + CCD + photometry software. Much cheaper than a huge radar antenna.
Arecibo/Goldstone type radars are not usually owned by amateurs...
or many of the recent papers on 'Oumuamua, like https://arxiv.org/pdf/1711.04927.pdf
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