Posts by Jon Golding

1) Message boards : News : Green Bank Telescope observations to start Saturday. (Message 1106581)
Posted 737 days ago by

Jon Golding

The link at the bottom of that news item http://seti.berkeley.edu/seti_at_the_gbt says that they will be using this equipment in future to piggy back on the Green Bank telescope

2) Message boards : News : Green Bank Telescope observations to start Saturday. (Message 1106449)
Posted 737 days ago by

Jon Golding

I just hope that none of these planets were behind their star at the time the observations were made. I guess that was one of the factors taken into account during the candidate selection process.

3) Message boards : News : Green Bank Telescope observations to start Saturday. (Message 1104382)
Posted 744 days ago by

Jon Golding

After the Kepler data are recorded, will we continue to piggy back and record data on the Green Bank telescope? Or is this a one-off?

4) Message boards : Near Time Persistency Checker : Please Read First! (Message 1101646)
Posted 753 days ago by

Jon Golding

Oh. Well that was short-lived. Seems like we've reverted back to just 10 candidates now.

5) Message boards : Near Time Persistency Checker : Please Read First! (Message 1101360)
Posted 754 days ago by

Jon Golding

Many thanks (to Matt, I guess) for publishing the Top 50 candidates.
These all seem to be from the same part of the sky. I'm guessing that we'll be called on to do some manual RFI detection on these plots?

6) Message boards : Near Time Persistency Checker : Candidate: 20581835 (RA: 22.895508 Dec: 16.432024) (Message 1098729)
Posted 764 days ago by

Jon Golding

All of the current top 10 candidates appear to be RFI.
Look at the spike data: each one has a consistent 1.4188GHz line that has been locked onto as the suggested signal. There's a similar line on the opposite side of the waterfall plot, so these are likely side bands around the main central RFI. These lines are persistently present and don't show any Doppler shift.
Could all of the current spike candidates be manually removed from the top 10, so we can see the (potentially) more interesting candidates that are further down the list?

7) Message boards : Near Time Persistency Checker : Candidate: 20581835 (RA: 22.895508 Dec: 16.432024) (Message 1088398)
Posted 794 days ago by

Jon Golding

Also, the ids suggest that all the data was acquired at about the same time...

Agreed. I've only checked a few of them, but the date comes out as during July 2008. Perhaps a dedicated study of objects near Pegasus was carried out during that time and this happened to coincide with a lot of 'noise' from somewhere? Nearby radar testing?
Alternatively, we've just discovered where ET hangs out.

8) Message boards : Near Time Persistency Checker : Please Read First! (Message 1086084)
Posted 802 days ago by

Jon Golding

Now that the NTPCKr is running again, any estimate as to when we'll see some updated candidate stats?

9) Message boards : Near Time Persistency Checker : Please Read First! (Message 1042735)
Posted 948 days ago by

Jon Golding

Great to see that the public face of the NtPCKr is back in action (as of Oct 13), complete with data, statistics, and much-improved waterfall plots. Things are looking up!

Many thanks to all involved, especially considering all the other fire-fighting you have to do at the moment.

10) Message boards : News : "Are We Alone?" The Great Debate (Message 1027704)
Posted 1002 days ago by

Jon Golding

The recent BBC article and interview with Seth Shostak is interesting because, among other things, it questions whether we're looking for the right kind of signal. Any civilisation following a similar technological path to our own will only be detectable by our radio telescopes for a limited period whilst they're using high-power omnidirectional radio to communicate around their planet. If they follow our path, then within 100 years they will switch to using lower-energy more efficient point-to-point communications, or they'll use fibre-optic. If true, that greatly lowers the odds of finding them by using a radio telescope.

11) Message boards : Technical News : June Update (Jun 02 2010) (Message 1000593)
Posted 1082 days ago by

Jon Golding

Jeff has been hammering on the NTPCkr to incorporate the newer RFI removal code. Before the plumbing was of the form: signals come in, pixels are scored, the best ones are displayed for the public to see. Now the plumbing is: signals come in, pixels are scored, the best ones are displayed in a sort of "preview" form and sent into the RFI loop, which then forces the pixels to be rescored (after bad signals are removed), and if they still happen to be in the top ten they'll have all the associated plots for the public to analyze.

So, is the RFI removal script now running constantly in the background, or does this script only get implemented every day or so?

12) Message boards : Near Time Persistency Checker : Please Read First! (Message 997305)
Posted 1097 days ago by

Jon Golding

Yeah! Looks like the NTPCKr is running again.
8 new candidates, although we don't yet have access to the full WU details.
Well done everyone at Berkeley.

13) Message boards : Technical News : Back in Town (Dec 07 2009) (Message 953460)
Posted 1259 days ago by

Jon Golding

Cheers for the update Matt. With all this work at hand I reckon you were bursting to get out of there for a bit. You're human just like all of us and deserve some kind of a breather.

-- Tom :-)

wait.... Matt is a human? awww.... I thought he was some sort of really advanded A.I.

Didn't you realise? - Matt is the E.T.I. we've been searching for all these years.
Talk about hiding in plain sight![/b]

14) Message boards : Technical News : Back and Forth (Oct 28 2009) (Message 943698)
Posted 1300 days ago by

Jon Golding

I was kind of hoping other radio telescopes had similar blanking woes thus we could get welcome invitations to meaningfully sized sites (ie: Russia's Ratan-600 or the under-construction Chinese FAST).

Especially nice if these telescopes can see parts of the sky that Aricebo can't, and the scientists involved reciprocated by agreeing to ship some of their blanked data to Berkeley for splitting into WUs (for appropriately modified client apps).

15) Message boards : Near Time Persistency Checker : Candidate: 920891 (RA: 2.645508 Dec: 26.547533) (Message 941056)
Posted 1311 days ago by

Jon Golding

Hi Tiaan
Humans can already achieve Terawatt power transmissions. Several research lasers since the 1970s can produce pulses in the TW power range; the most powerful being at the National Ignition Facility (about 700TW). The point is, would we want to use all that resource to beam a signal out into space at a planet where we don't even know if there's anyone advanced enough to receive it?
My only point here is, why bother transmitting signals at any power more than you really need to? If ET thinks the same way, then we're only going to pick up a signal deliberately sent at us (of which there may be many) and we're currently going to miss all of those 'business as usual' civilisations that are only using sufficient power to send signals around their home world.

16) Message boards : Near Time Persistency Checker : Candidate: 920891 (RA: 2.645508 Dec: 26.547533) (Message 941050)
Posted 1311 days ago by

Jon Golding

Agreed!
One popular idea out there on the message boards is that SETI will pick up signals from a civilisation just going about its normal business - we'll be eavesdropping on their TV, radio, or radar.

However, using our own TV/Radio/radar transmissions as a guide (see http://www.faqs.org/faqs/astronomy/faq/part6/section-12.html), human transmissions could not be detected with an Aricebo-sized dish at a light year distance. So, we're only likely to "eavesdrop" on ET if their civilisation extends over a few planets/solar systems - something that might require them to increase the power of their transmissions above that for "standard" terrestrial point-to-point communication.
It seems more likely that any signal we pick up will have been deliberately pointed at us (possibly on the basis of a "life" signature in our atmosphere). No-one knows how aliens think, but humans certainly wouldn't spend years and years blasting a (very expensive) signal towards a planet that may or may not harbour a life-form that could receive it.

[edit]
BTW, I'm not saying we shouldn't be looking for these signals - Quite the opposite. We ought to be using a receiver that could detect much weaker transmissions (e.g. an antenna size that could detect our own radio transmissions at over 10 Lyr).

17) Message boards : Near Time Persistency Checker : Candidate: 920891 (RA: 2.645508 Dec: 26.547533) (Message 939856)
Posted 1315 days ago by

Jon Golding

Hi Tiaan

From Matt's posts, it seems that the database takes quite a pounding each time they run the NTPCKr. So, I don't expect an updated candidate list until things have calmed down with the current server problems. Also, Eric was apparently testing some RFI rejection software, so maybe they want to combine that with the NTPCKr to make the next run more meaningful.
According to that calculation page, it seems that a 120 terawatt transmission (2.3Ghz, 0.1Hz bandwidth) from 1700 Lyr away, could be detected by Aricebo. No idea how feasible that technology would be.
Anyway, we're pretty much all decided that this one is just random noise.

18) Message boards : Near Time Persistency Checker : Candidate: 920891 (RA: 2.645508 Dec: 26.547533) (Message 939776)
Posted 1315 days ago by

Jon Golding

Hi John & Tiaan

In answer to my own question, this link http://www.faqs.org/faqs/astronomy/faq/part6/section-12.html
was posted in another thread and indicates the detection distance limits for various frequency ranges and types of signal.

19) Message boards : Near Time Persistency Checker : Candidate: 920891 (RA: 2.645508 Dec: 26.547533) (Message 939215)
Posted 1318 days ago by

Jon Golding

I also find this fascinating.
Many thanks for all the additional stellar-type info, which certainly increases the probable distance to this star.
However, although this is the first example the NTPCKr has produced of a candidate with a star in the field of view, the pulse data looks like RFI. I have no comment about the Gaussian, spike, and triplet data, which (without further analysis) may be "real". Nevertheless, it's interesting to consider just how powerful any transmitter would have to be for us to pick it up at over 1700 light years! I guess it could have been deliberately broadcast at us, if the sender had realised that our atmosphere signature indicated life (just as we're planning to do with the upcoming generation of space telescopes). Even so, it would have to be one heck of a transmitter.

Off topic: it would be really useful if the waterfall plots were colour-coded according to signal strength, as they are in the old newsletter about waterfall plots http://setiathome.berkeley.edu/sah_sci_newsletters.php?frag=news-6.inc

20) Message boards : Near Time Persistency Checker : Candidate: 920891 (RA: 2.645508 Dec: 26.547533) (Message 939171)
Posted 1318 days ago by

Jon Golding

@Tiaan
I'm not an astronomer, but a Google search came up with two articles that, together, might permit an estimate of the distance to this star.

1) The astronomy lecture notes on magnitude-distance, by Hans Krimm http://ceres.hsc.edu/homepages/classes/astronomy/spring99/Mathematics/sec19.html
state that the distance to a star can be calculated from a knowledge of its absolute magnitude (M) and its apparent magnitude (m).

The equation is: distance in parsecs = 10^((m-M +5)/5)

2) In the paper by Martin, E.G. (1945) "The absolute magnitudes of the stars of type K0" The Observatory, Vol. 66, p. 82-87.
http://articles.adsabs.harvard.edu//full/1945Obs....66...82M/0000087.000.html
Table III shows the absolute magnitudes of several K0 type stars. The spectroscopic values are surprisingly reproducible, with an average absolute magnitude of 2.3

3) From what I can understand of the stellar catalog codes for this star, it has an apparent magnitude (Bt) of 10.94

4) Putting all of this together:
(10.94-2.3+5)/5 = 2.728
10^2.728 = 534.56 parsecs = 1744 light years.

I have no idea if this is correct.

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