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My astronomy project:
Making of a heating band or dew heater


Making of an Observatory

Page IV

  1. Part 1: One more USB dew heater

Part 1: One more USB dew heater

When I use my my dew heater on my Sigma 150mm f/2.8 lens I have noticed sometimes that it's almost impossible to get it in perfect focus. I have an idea that it's arise from the dew heater. My special built dew heater is very thin and just touch the narrow space at the front lens. Maybe that's the problem, uneven heating of the lens. I have now purchased a much bigger dew heater band that cover the whole lens to doing test with.

USB Dew Heater

Looks very good and with straps to hold it in place.

Canon 6D with Sigma 150mm APO f/2.8

This is how my lens look, now I have to attach this big dew heater all over the lens barrel. Then I also cover the focus ring. That maybe will be a problem, but if it solve my out of focus problem it's ok.

Canon 6D with Sigma 150mm APO f/2.8 and Dew Heater

Here the lens with the dew heater mounted. I use the same battery as earlier, an USB power pack with 10 Amp/h capacity. Last for more then one night. The dew heater takes 0.8 Ampere, 4 Watt. I report back when I have tested it.

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