Originally posted by Anthony:
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Still, go ahead and assume waste heat = 1/10 of PP output.
OK.
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Would be analogous to a mean surface temp of 123 degrees celsius ....
No, because it's actually 1400W x cross-section, not 1400W x area. It's actually analogous to a mean surface temp of about 0C.
</font>[/QUOTE]Just used Stefan-Bolzmanns law:
M = o x T^4
Thought You gave specific radiation M with 1400 W/m^2...
How did You calc the 0 C ?
Going through some math, a typical 200 dT ship:
Cross-section: probably around 200 square meters.
PP output (assumes 2G): 1 gigawatt.
So you are assuming 100 MW waste heat in active mode ?
This reminds my of a monster thread in the TML, where people wonder, how to get rid of these amounts waste heat...
Could you present the calcs for the following ?
Apparent magnitude at 1 AU (spread over the spectrum)
When inactive: ~26
When active: ~17
Probable limits of detection: we could build a telescope today that can spot magnitude 26 objects, if we know where to look. Scanning the sky is much much harder, but asteroid watch programs scan large portions of the sky at magnitudes of 20-22, taking a week or so to scan the entire sky, and could probably reasonably be designed to scan down to magnitude 15-17 in an hour.
Do You know, which areas of the spectrum are scanned for asteroid watch ?
I guess it may be difficult to differ between an asteroid/starship, even if you detected "something" out there. Perhaps a spectrum analysation would help...
Oh, and another question as You are dealing with stellar magnitudes.
Could You describe how to convert from specific radiation intensity W/m^2 to magnitude values ?
I used to work with W/m^2 or W/sr normally.
Regards,
Mert