[/b][/quote]

These are my thoughts about the Mercury Timeframe

Regarding a Mercury TimeFrame.
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First the hard data:
1: Mercury has no tilt.
2: Rotation around sun : 0.24 EYear = 87.66 Eday. (E=Earth)
3: Rotation around Axis: 1408 Ehours = 58.66 Eday
(source: www.nasm.edu/ceps/rpif/mercury/rpifmerc.html)

The first observation is that no tilt implies that there are no seasons. No seasons
means that people living on the planet do not (explicit) experience a year go by.
Only if they look at the night stars they might do so.

Second observation is that a MercDay is very very long in terms of Eday's, too long to get used to. Next the ratio between a MercYear and a MercDay = 0.6691.
[Note ArcSin(0.6691) = 42, see Hitchhikers guide to the galaxy ]

The effect of the long day is a very hot dayside ~700Kelvin and a cool nightside
of ~100 Kelvin. These temperatures imply that a human colony can only survive in
the twilight zone. The radius of Mercury is 2439 km => the equator = 15324 km.
At the equator the twilight moves at 15324km/1408 hours = 10.88 km/hour. This is more than 2 times as fast a human could walk. It will be very difficult to have a
human settlement moving constantly at this speed. However it would be good for
exploration, and in the early days humans were moving all the time too, so nothing new. Another option is to dig in the crust for 58 days.
So the only real suitable places for a human colony are the north and south poles
of Mercury. At a lattitude alpha the incoming sunlight is COS alpha times as strong as on the equator.
alpha = 89 degree (radius around pole = 15324/260 = 42 km) => sunlight = 2% of equator
alpha = 89.9 degree (radius = 4.2 km) => sunlight = 0.2% of equator.
So we can savely assume that it will not be that hot on the poles, but if you
stick up a solar panel (right angle) it will be flooded with sunlight, so plenty of energy if you want to. But staying at the poles would imply that someone on Mercurybase 1 can walk from dayside to nightside in a few Ehours or less. Practical speaking they live in the twilight constantly.

Conclusion
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What does this mean for a day time framework for mercury? The planet itself does not give any usable timeframe as no seasons exist and the MercDay is way too long to get used to. Furthermore a human settlement need to stay in the twilight to have a controllable climate for a longer time. So there is no real day rythm experienced either. So for mercury I would propose to just use the Earth timeframe.

regards,
rob tillaart
PS,
Venus is not colonizable with current earth technology so let us use Earth timeframe for Venus too.