Nitrogen filled?

[Aaron1996]

Hello,

In the U.K., do binocular astronomers run any risk of internal fogging/condensation? Any experience? I've noticed Nikon 10x50 for £69 but no nitrogen filling.

Thanks and a happy new year to you all.

Regards,

Bill.

[BinocularSky]

Hello,

In the U.K., do binocular astronomers run any risk of internal fogging/condensation?

Yes. However, if you keep you binocular somewhere cool and dry, it needn't be a problem. For peace of mind, keep a silica gel sachet in the binocular case, and "recharge" it periodically.

[Muphrid]

If you keep your binoculars above dew point, you will not get any fogging inside. The simplest way to do this while using them on a cold night is to keep them inside your coat when you're not using them. At the end of your viewing session, put the eyecups on them and put them in the case BEFORE going inside. That will reduce the chance of moist air condensing on the inside.

[Aaron1996]

Thank you Steve and Muphrid for your practical advice. Always something to think about!

Regards,

Bill.

[BinocularSky]

If you keep your binoculars above dew point, you will not get any fogging inside. The simplest way to do this while using them on a cold night is to keep them inside your coat when you're not using them.

The dew-point point is spot on, but you can find that the cooled binocular is below dew-point for the humid air inside your coat (easy to tell -- if the objectives are misty after 30 seconds inside your coat, then dew point has been attained -- but they will clear after a few minutes as they warm up). I always pop the rain-guard over the eyepieces whenever I take them from my eyes -- it becomes second nature.