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Rule of Thumb – Planets, Double Stars


Notes:

There has been a lot of material presented in this talk. I will attempt to summarize it in two slides.

You have checked the weather forecasts and the night will be clear. Where should I go? Well that answer depends, in part, of what you want to look at.

If you want to look at Double Stars and/or Planets you may get a different answer than if you want to look at Deep Space Objects (nebula and galaxies). Star Clusters (open and globular) fall in between these two broad categories.

Planets (except Pluto) and most Double Stars are not affected (as much) by light pollution. In principle you can observe them from the city (although the light may effect your ability to see a dim companion) or during a full moon. The most critical consideration in this case is to find a spot where the skies are steady. I have listed some of the local sites that have laminar flow. I am only familiar with Fremont Peak and Montebello.

Paradoxically you might actually have the best seeing when the sky is about to form fog. At about 4 AM on two nights at the last CalStar we had perfect seeing. That was moments before the area was covered in fog. Similarly I have done star tests while the sky was becoming overcast. It all depends on the turbulence. Any site can potentially have good seeing. It just is more likely some places than others.