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Anybody use I-M M715 in the winter?

Started by jwilson, 03/10/2005 07:40AM
Posted 03/10/2005 07:40AM Opening Post
Hello everyone...

I'm considering getting an IM M715. The only reviews I can find are positive but they seem to be from observing sessions in warm weather and I'm wondering about use in the cold of winter... Does anyone have experience using one of these scopes in the cold? Does the fan help keep the image stable even after cooldown?

Posted 03/10/2005 08:27PM #1
I have the I-M 715 DX. I live in Wisconsin and observe in the cold. I was out last week when it was below 10 F and two nights ago when it was about the same temperature. If I have time and plan ahead, I put the OTA outside with the case open for an hour or two before I head out to observe. When I am ready to observe the OTA is in good shape requiring maybe another 15 minutes with the front cap off to settle in. Some times this is not even necessary. Once the optics are stable, I put on my flexible dew shield to prevent frost. With this approach I do not need the fan at all.

If I do not have time, then I find I need to set the scope up and run the fan for about 45 minutes to cool everything down. It is close to zero, the cool down will extend to an hour. After that, I put the dew shield on and I am good to go for the rest of the night.

Once the scope is stable, if never find I need to run the fan.

The dew shield does a great job in summer and winter. During the last lunar eclipse, we had a very cloudy and damp night here in the land of cheese. I put the shield on and my front corrector was perfect all evening. If I do not use it, the glass gets covered in dew quickly.