whens the best time to take pics of the sky on madeline isalnd?

The later in the week, the better chance of getting dark skies. Full moon was August 1. The full moon rises just as the sun is setting. Last quarter is August 9. A last quarter moon usually rises approximately midnight.

You can go to

http://www.wunderground.com/

look up your location, and look in the astronomy section for local sunset, twilight, and moonrise information. However, although they have an almanac section for dates in the past, I don't think they provide this information for dates in the future.

Auroral activity is sometimes visible from your location, but only if it is exceptionally strong. Nothing that strong is predicted in the near future, although predictability is not great very far in advance.

http://www.gi.alaska.edu/AuroraForecast/NorthAmeri...

What kind of sky pictures do you have in mind? Sunrise and sunset pictures can be tricky, and often disappointing, as the camera has less dynamic range than the eye. It can help to have a certain amount of twilight to fill in your foreground. Ken Rockwell gives an example here:

http://www.kenrockwell.com/tech/timing.htm

This is a telephoto shot of the midday sun peeking above the southern horizon at Barrow, Alaska in November, a few days before disappearing for the season.

http://www.martingrumet.com/alaska16nov10-07barrow...

Notice how dark the foreground is. It is of course very misleading. Using a high enough shutter speed to allow the orb of the overexposed sun to be distinguishable, the foreground is very underexposed to the camera. To the eye the scene was not nearly that dark.

This shot looking north taken a few minutes later is about how things really looked in the afternoon twilight:

http://www.martingrumet.com/alaska16nov10-08barrow...