[TML] The Sky at Night?

[Ewan Quibell]

Patrik Holmstrom wrote:
> On Dec 3, 2007 2:50 PM, John Kwon <jtkwon at jtkgroup.com> wrote:
>> On 12/3/07, Patrik Holmstrom <patrik.holmstrom at gmail.com> wrote:
>>> On Dec 3, 2007 1:07 PM, Timothy Little <tim at little-possums.net> wrote:
>>>> On Mon, Dec 03, 2007 at 11:18:44AM +0000, Ewan Quibell wrote:

>>>>> Would the F7 V just look like a bright star or would it produce
>>>>> something like moon light?

>>>> It would illuminate about the same as a bright full moon, yes.  It
>>>> would be a very dazzling star, apparent magnitude probably about -13.
>>>> I don't think it would actually be dangerous to look at: despite the
>>>> pointlike focus on the retina, the light passing through the pupil
>>>> would be less than a microwatt.

>>> That looks like it is in the ballpark. Assuming a luminosity of 2.1
>>> sol I get an apparant magnitude of -14.5 or 6 times brighter than mean
>>> full moon luminosity (-12.6).

>> So we wouldn't need night vision devices, and we could read our comp-pads
>> without using the backlight.

snip

> Also the frequency of those clear nights are another matter. Bitter?
> Me? Got myself a new telescope a while back and the only clear night
> in the last 4 weeks had hurricane strength wind gusts...

But at 6x Moonlight on a clear night would you still get the equivalent 
of Moonlight on an overcast night?

And what about the other way around? Say if the primary was the F7 V and 
the companion was the G2 V at 1000AU, what would the apparent luminosity be?

Best Regards

Ewan
-- 
  ewan at quibell.org.uk

  They shall grow not old, as we that are left grow old;
  Age shall not weary them, nor the years condemn.
  At the going down of the sun and in the morning
  We will remember them.
			Laurence Binyon

  My spelling is entirerly due to dyslexia, typos, and poetic license