Re: HST and Iridiums
Robert G Fenske Jr (fenske@rgfpc.electro.swri.edu)
Wed, 11 Feb 1998 18:53:01 -0600 (CST)
On Wed, 11 Feb 1998, Eberst wrote:
> So HST could see an Iridium flare of magnitude -11, or nearly full Moon
> brightness.
> I believe HST is programmed to avoid pointing at the Moon, but I suspect that
Yes, it avoids the Sun, the Moon, and of course the Earth. An
optimal flare would be worse than the Moon because the flare would be
brighter per unit area than the Moon. The -12 mag of the Moon is it's
brightness integrated over it's whole disk and not a near point source.
> the controlling scientists are not aware that there is the possibility of damage
> to the extremely sensitive and delicate sensors on board, from such an intense
.
.
> sufficiently bright to cause some damage. Does the HST have software that
> ensures avoidance of objects like Venus, Jupiter, Sirius,etc?
Since it's already taken a good number of pictures of every planet
except Mercury (which is probably always too close to the Sun for
comfort), I would say there's no particular requirement to avoid them ...
> I expect that the controllers would be glad to receive warning of any such
> devastating flares, and it is interesting to know if HST would experience
> such events once a day, or once a week, once a month or once a year?
> My impression for ground based observers is that there are around 8-10
> 'monster' flares a month for any one site. (I admit a lack of
> experience of the numbers of daylight flares: anyone care to comment)
A quick check reveals that for the month of Feb. I have 13
predicted flares with < .25 deg angle, 10 of which are in the daytime.
Robert Fenske, Jr. rfenske@swri.edu Sw |The Taming the C*sm*s series:
Southwest Research Institute /R---\ |
Signal Exploitation & Geolocation Div | I | |"The Martian canals were the
San Antonio,Texas USA ph:210-522-3931 \----/ | Martians' last ditch effort."