[Wavytone]

1. Reflection off a distant insulator, suffers from air turbulence and thermals.

2. A ball bearing - outdoors it can be placed where it is illuminated by the sun, (don't leave it, they rust), suffers from air turbulence and thermals as above.

3. Indoors a ball bearing can be illuminated by the reflection of a bright lamp - anything from a torch will do strongly recommended if you have a long corridor or garage or similar with still air and no thermal gradients.

4. Tiny hole in aluminium foil, illuminated by a small bright source, used indoors as above.

I've tried all four before and the best by far is #3, I used a body corporate underground carpark late at night.


If you have no choice except doing it outdoors, try to make sure the optical path is over ground that is a garden or grass, in shade. Try to avoid a path over ground that is in the sun, hot/cold paved areas (concrete, brick, tar) or a fence or wall heated by the sun.

Outdoors the turbulence in daytime is usually so bad it will limit you to grossly out of focus images which won't tell you much. The really interesting aspects are what you can see in a highpower eyepiece chosen such that you should normally be able to resolve the Airy disk and rings, only slightly in/out of focus. Using low power eyepieces will tell you nothing useful unless the scope is horrendously out of whack.