[TML] The Sky at Night?

[Jerry W Barrington]

On 12/3/07 11:08 AM, Garry Ward wrote:

> according to my notes, a V luminosity star can be anywhere from 1/10,000th
> to 1,000 times the brightness of the Sun, so first thing you need to decide
> is where the companion lines on that scale. It can be barely visible at the
> low end or as bright as the sun at the high end.

That's what the G2 or F7 part tells you...



On 12/5/07 1:02 AM, Patrik Holmstrom wrote:

> After checking why Tim got other numbers than than me I found a slight
> error in my spreadsheet. For a F7V (lum=2.1) I get an apparant
> magnitude of -12.6 and the G2V (lum=1) gets -11.7 which is full moon
> resp. half that. The light during overcast conditions would of course
> depend on exactly how thick the clouds are. I have found numbers from
> 3-15% but I have no idea how valid they are. Anyone?

What tables are you using for luminosity, etc?

>From [CT] Scouts, p. 44, G0V is 1.21 and F5V is 3.5.  That would interpolate
to 2.584.  (You take the 4th root of this for temperature calculation, which
explains the difference with the next...)

>From the [MT] World Builder's Handbook, p. 64, it's 1.05 and 1.37.  yielding
1.242.  (2.38 when raised to 4th power to put in CT terms.)

>From Traveller 2300 Referee's Manual, p. 38, it's the same as Scouts.

TNE just used a table of habitable orbits, no luminosity given.

T20 just has a temperature modifier for each luminosity class.  :P

I don't know enough about T4 or GT to look for any luminosity data there...

In any case, I'd be interested in any tables of stellar attributes,
especially if they are more accurate than the old ones we have.  Same
question to Timothy too, I suppose.  :)