Adjust the FOV constant so projected area stops at 350 km

[peschman]

As discussed during our conference session, we should lower the distance value used to calculate camera FOV. Let's change the value so that the FOV projection stops at 350 km. This will reduce some of the sharply pointed narrow lower extensions we see for some cameras. These are areas where there is no useful overlap with other cameras.

I'm not sure where this constant is set in the code. Currently, it may be set to 400 km. This change should only alter the FOV graphic representation, and should not change the distance at which events are recorded.

Peter E.

[Cybis320]

Right now, it's an elevation cutoff (5 deg). Is it really unreasonable?

At 5° elevation:

• 25 km: 235 km ground distance
• 70 km: 535 km ground distance
• 100 km: 695 km ground distance

A high altitude station in a dry atmosphere could probably see a bright event at those distances, no?

[dvida]

I think what's Pete is saying is that in practice, very few are observed at such large distances. Bright fireballs (below 70 km) may be observed at such extreme distances, but faint meteors (~100 km) can't due to extinction and range sensitivity loss, which scales as 5*log(100/r) where r is range in km, so at ~700 km that's over a 4 mag loss! And that's not including extinction loss which is another 3 magnitudes at the elevation of 5 deg.
The 350 km cap is very reasonable.