Telescopes... but radio?

[pipnina]

I was looking on the FLO website and stumbled upon these: http://www.365astronomy.com/RADIO-TELESCOPES/

The first thing I did was black out trying to read the prices. After I recovered I wondered how it works.

Is it a single pixel? Does it produce a spoectrograph or an image?

Is it affected by interference from audio radio signals/GPRS?

Doesn't the atmosphere reflect/absorb radio signals? Does that mean I'd get images of... what?

Can I see aliens with it?

How does it cost that much?

(P.S. Not sure if this is the right place)

[hazegood]

it would be your own personal mini Jodrell bank

[beamer3.6m]

£25k... wow.

Can these be made by diy'ers.

[pipnina]

£25k... wow.

Can these be made by diy'ers.

An interesting thought. I'm imagining 90% of the cost is in the sensor and the mount.

Else, 15~k for a parabolic metal dish (That's mesh as well)?

[FenlandPaul]

Wow. That seems like an awful lot of money for what it is. Radio astronomy is meant to be an electrical engineer's amateur paradise, so I'm sure if you know what you're doing you could set up something for far far less than that that is functionally the same (even if it looks a bit rough round the edges). When I was a lad I had the privilege of being invited to see the UK amateur radio astronomer John Smith's set up at his home near Guildford. He had built in his back garden a mesh dish that must have been 10 - 15m in diameter and had yagi arrays all over. The large dish was steerable using an old Sinclair ZX (the one with the rubber keys that fell out if you turned it upside down). He gave me a load of oscilloscopes and chart recorders to take back to my school.

My point is he definitely didn't buy his set up new and he was doing real science. It might not have been as shiny, but I'll bet it was more effective!

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[Joe_L]

£25k... wow.

Can these be made by diy'ers.

Yes. Back in the 80's I helped a friend make a 3M one (it did get the neighbours twitching the curtains as we started assembling it in the garden).    Another friend knew someone who had made a 10M one but he lived on a farm so space wasn't an issue. Chicken wire and aluminium sections - the main issue is getting the geometry accurate enough for whichever wavelength you're intered in.

Joe

[beamer3.6m]

What does radio astronomy actually show. It is lines on a graph for example.

[Gazabone]

I've toyed with the idea of trying to build one to the extent that when me Sky TV was renewed a few weeks ago I managed to keep the old sat dish. However, I'm told you need to be quite into tinkering with radios to get them to work and I'm not so I think the old sat dish might just stay put for a while before being chucked out. Either way I doubt it's big enough for radio astronomy.

I guess these ready made kits would be rather more successful but I think there's a few other things on my Astronomy Want list before a radio telescope.

Exeter Uni were looking for pledges a few months ago to finance a radio telescope near Liskead in Cornwall (just up the road from me) and £1k was enough to buy the right to name it and use it. Never heard how it worked out though.

[pipnina]

What does radio astronomy actually show. It is lines on a graph for example.

Mostly what I'm wondering, tbh.

Mind, scientific radio telescopes tend to produce fuzzy images: http://lhsgems.org/images/m51BottomLeft.gif

[Pompey Monkey]

Mostly what I'm wondering, tbh.

Mind, scientific radio telescopes tend to produce fuzzy images: http://lhsgems.org/images/m51BottomLeft.gif

A 2.3m aperature dish at Ku-band (12-18GHz) can theoretically resolve down to about half a degree. Not sure how much detail in the sky that would show.

On the other hand if you combined two or (many) more dishes in an array as an interferometer, you could get a lot more detail. Now where have I heard that idea before?