I was out observing last night. The sky was not too bad, but it was VERY humid (60% +) and cold (low 30's). This is in my backyard in west Phoenix. I used dew heaters on both my scopes and had no problems. Without the dew heaters they would certainly have dewed up. They are both SCT.
Tonight will not be as humid as last night, but still very wet for Arizona. It will also be cold and combined with the high humidity will require bundling up well (including head, feet and hands). If you are using a SCT or refractor a dew heater is highly recommended. A dew shield will help, but may not be sufficient.
Last night the sky was very clear, but unsteady. It may be better tonight. Jeff -- Jeff Hopkins HPO SOFT Counting Photons http://www.hposoft.com/Astro/astro.html Hopkins Phoenix Observatory 7812 West Clayton Drive Phoenix, Arizona 85033-2439 U.S.A. www.hposoft.com
