Re: Pictures of Pluto
 

It still is a planet. A rose by any other name...

Re: Pictures of Pluto
 

It should really set itself up with an Instagram account so we can see these pictures with trendy filters and witty captions

Re: Pictures of Pluto
 

The images looks awesome so far. :thumbup:

Re: Pictures of Pluto
 

Not sure if you were being sarcastic or not but....

https://instagram.com/nasa/

Re: Pictures of Pluto
 

I was, but that's very cool.

Re: Pictures of Pluto
 

Will xkcd do ?

http://imgs.xkcd.com/comics/pluto.png

Re: Pictures of Pluto
 

I agree with the OP. It will take about 7 minutes for the signal to reach the probe to position to camera, position the antenna, and start taking pictures and then 7 minutes to start receiving the pictures back on earth.

The beam has to be extremely narrow and accurate since the probe doesn't have that much power available. It is likely that the probe can only transmit at a few watts of power but with a very narrow beam, the effective transmitting power could be effectively increased to millions of watts so by the time the signal reaches earth, it will likely be in the micro watts which may be enough to receive the picture.

Re: Pictures of Pluto
 

Actually its 4.5 hours there, 4.5 back.

So all activities are preplanned in advance and run off a queue that's uploaded ahead of time.

Signal bandwidth is ~ 1-4 kbit/s

Signal strength at Earth is 0.00000000000000000004 watts ........

Re: Pictures of Pluto
 

You are correct. I miss calculated.

Re: Pictures of Pluto
 

That appears to be 40 zepto-watts. I suppose with a large enough dish, that little bit of power can be received.

https://en.wikipedia.org/wiki/Zepto-

Re: Pictures of Pluto
 

:eek:

Re: Pictures of Pluto
 

At least we know how to destroy it if the Plutonians attack us.

Re: Pictures of Pluto
 

Can anyone help a simpleton like me understand how the pictures get back to us? Is it just like an interstellar version of wi-fi? And how does New Horizons know where to send the pictures to, given that Earth will be a miniscule dot 1 gazillion miles away.

BB

Re: Pictures of Pluto
 

The New Horizons probe knows roughly where the Earth is, and the small dish that it has has quite a wide beam. So it aims roughly in the right direction and transmits the radio signal, complete with a metric ton of error correction codes. Datarates are about 1kbit/s.

Much bigger dishes on Earth also know where the probe is (clue, it's where Pluto is) and use lots of smart techniques to pull the very faint signal out of the background. Those error correcting codes then correct for noise, and check there's no corruption.

Unlike with wifi, if there is a dodgy packet you can't really easily ask for a retransmit (9 hours for a reply) so there's much more emphasis on error correction.

Oh, and because New Horizons was done on the cheap, the camera is fixed to the probe body, not movable. Therefore to direct the camera it has to move the entire probe to point in the right direction. Downside of that is the dish is then not pointed at earth and it can't transmit. So it's only either gathering data or communicating, not both at the same time. That also means Earth can only talk to the probe when it knows the probe is listening.

Oh, and for knowing what angle you are at there are INS units, and at a pinch, star trackers - that can orientate the probe relative to known star positions.

Re: Pictures of Pluto
 

It's one of those questions like 'Why is our galaxy named after a bar of chocolate?' No-one knows.