Umbrella For Night-Sky Photography

[ElizaMM]

I did not record the source, but somewhere I read about the night sky absorbing radiative heat -- in this case from a camera lens -- and that placing an umbrella above your camera slows down the cooling of the lens. Can someone explain in a little more detail, or direct me to a URL? I am not asking about keeping the lens warm with hand warmers, etc. -- I just want to understand a bit about the workings of radiative heat, as it relates to photography equipment, while shooting the night sky.

 

[480sparky40 39]

What is it you're trying to accomplish? Eliminate condensation?

 

[ElizaMM]

Yes.

 

[ElizaMM]

That is yes, but... My main goal at the moment is to understand radiative heat & lenses.

 

[tenjac]

That is yes, but... My main goal at the moment is to understand radiative heat & lenses.

I have often wondered about this same phenomenon, but in a more general sense, not as related to photography. I first became curious about it while working on railroad track(my career). I noticed that on clear, cold mornings black colored wooden railroad ties would often have frost on them, while lighter colored ties would not. I have done a little research on the matter but information about it is surprisingly elusive. Apparently, objects which absorb radiative heat readily due to their color also radiate heat into space at the same rate. When this radiation is not offset by sunlight or