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Comment: Put you money in the mount (Score 3, Interesting) 185

by mbone (#47739287) Attached to: Slashdot Asks: Cheap But Reasonable Telescopes for Kids?

Get the best (Ha-Dec) mount you can. (I would not get an Alt-Az mount for a beginner on a budget.) Most department store type scopes have adequate optics, but very crappy mounts, and that makes for a miserable viewing experience. Get a very sturdy mount with a cheap scope,and then if the kid wants to move up, they have the mount for it.

Comment: Re:Is it too late? (Score 1) 137

by mbone (#47738679) Attached to: 2 Galileo Satellites Launched To Wrong Orbit

Most major GPS chip sets now actively filter pulsar noise.

Got a link for that? I know that most pulsar observers filter out GPS and other satnavs (GLONASS sidebands are especially annoying) but I have not heard of GPS receivers having pulsar ephemerides.


The thing about pulsars is they are better clocks than what is being launched and they transmit on all frequencies. The ephemeris calculations are much harder but it has be used to 2 meter accuracy and it isn't even limited to working just around earth. I wonder why they spent so much money to duplicate two existing systems that weren't even state of the art when they started. Maybe it was because you can't license pulsar transmissions.

Or maybe because observing pulsars requires a substantially bigger antenna than a hand-held smart-phone - 170 m^2 (and 500 Watts!) for a phased-array radio dipole and 0.1 m^2 for an X-ray Pulsar Nav system in Becker et al. (and the latter could only be used in space, outside the Earth's atmosphere).

Comment: Re:ugh (Score 1) 137

by mbone (#47738551) Attached to: 2 Galileo Satellites Launched To Wrong Orbit

The Fregat has a reputation as being an incredibly reliable and accurate upper stage - I have heard of on-orbit accuracies on the order of 100 meters - and there were no initial reports of upper stage technical problems (such as a premature shutdown). That tells me that this is likely to be either a communications problem, or a simple screwup.

Comment: Re:Stupid metric system (Score 1) 137

by mbone (#47738491) Attached to: 2 Galileo Satellites Launched To Wrong Orbit

Not quite - it's more that there were a number of different units for different purposes and different locations - inches and feet and rods and yards and chains and furlongs and fathoms, etc. (and these are just for length - there are acres and oxgangs and virgates etc. for area, and on and on). Over time, some of these dropped out and the others got rationalized, leading to a bunch of different ratios.

At least some of the duodecimal units (and I believe all of the base 360 units, such as degrees) are straight from the Babylonians.

Comment: What a debacle (Score 5, Interesting) 137

by mbone (#47736417) Attached to: 2 Galileo Satellites Launched To Wrong Orbit

This will for sure mess up the constellation, which is designed to minimize the times where some places on Earth do not have 4 satellites above the horizon, and also the places where this is going to happen (i.e., coverage gaps over the far South Pacific are likely to be more acceptable than over Northern Europe) . Since these satellites are too low, they will have shorter periods and will thus not be commensurable with the existing constellation, and will drift in and out of place.

You can be sure ESA engineers are busily looking at orbits this weekend, to see what can be salvaged from this debacle. Now, they may be really lucky, and have gotten an orbit where these two satellites can be used to fill a hole in the current constellation. I would bet in that case that both satellites would serve to fill the spots normally filled by one satellite; so at best only one, but if (as is more likely) they are unlucky, two satellites will have to be launched to fill the gaps.

In other words, while these satellites are not a loss, and will be used, new launches are likely to be necessary to make the constellation whole, which will cost as much as if they were lost.

Comment: I suspect the Japanese (Score 1) 116

by mbone (#47708125) Attached to: Scientists Find Traces of Sea Plankton On ISS Surface

I suspect the Japanese, and specifically the Japanese resupply modules (and that is not a joke). They are launched near the coast from a culture that makes extensive use of sea-weed; either way there could be contamination with sea plankton.

The idea that plankton could drift by itself up to orbital regions is... interesting. The idea that it could survive a 7 km/sec impact with Station is not; I don't think that is viable on either sense of the term.

Comment: Pretty obvious (Score 5, Insightful) 115

by mbone (#47693875) Attached to: Feds: Red Light Camera Firm Paid For Chicago Official's Car, Condo

What, you think that these cameras were set up after a careful consideration of how to balance the needs and rights of the citizenry against the desire to improve traffic conditions? No, it's based on lobbying by the camera sales staff, promising easy money in return for a right to prey on the citizenry. This being Chicago, some of the easy money was kicked-back to the local politicians, but the process isn't really that much different in regions where there is enough moral fiber for the state to keep all of the proceeds.

Comment: Re:Wont matter (Score 5, Insightful) 158

by mbone (#47656413) Attached to: Sniffing Out Billions In US Currency Smuggled Across the Border To Mexico

Problem here is they are not looking for anything that is evidence of a crime. It is legal to carry money over the border up to a certain amount so, the smell of money doesn't actually indicate any crime, and isn't evidence of any crime.

Won't stop them from seizing it anyway.

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