Cold weather

[Googinhiem]

I recently bought an 8" skyline dob from orion. When I bring it inside for storage should I cap it outside or bring it in and let it warm up first?  What about lenses? I don't want to trap condensation in the OTA. Any advice would be very helpful. I want to use this scope for many years and would just like to know how to best care for it. Thank you. 

[Putaendo Patrick]

A lot depends on conditions, as you say, and the position of the planet. I generally get best results between x120 and x180 magnifications. In your telescope with a focal length of 1200mm, these extremes would be 10mm and about 6.5mm.

The choice of eyepiece depends in part on money, but also on design. A Plossl at 10mm will have a comfortable eye relief at 10mm, less so at 6.5mm. I also like orthoscopic eyepieces, but again the eye relief is limited. BST Starguiders or Paradigms (same EP under different branding) are also excellent mid-priced eyepieces with good eye relief. Personally I don't like wide field of view EPs for planetary observing, I find it distracting - although with a Dobsonian mount, your target will say visible for longer between nudges of the scope.

[faulksy]

34 minutes ago, Putaendo Patrick said:

A lot depends on conditions, as you say, and the position of the planet. I generally get best results between x120 and x180 magnifications. In your telescope with a focal length of 1200mm, these extremes would be 10mm and about 6.5mm.

The choice of eyepiece depends in part on money, but also on design. A Plossl at 10mm will have a comfortable eye relief at 10mm, less so at 6.5mm. I also like orthoscopic eyepieces, but again the eye relief is limited. BST Starguiders or Paradigms (same EP under different branding) are also excellent mid-priced eyepieces with good eye relief. Personally I don't like wide field of view EPs for planetary observing, I find it distracting - although with a Dobsonian mount, your target will say visible for longer between nudges of the scope.

wrong forum

[faulksy]

52 minutes ago, Googinhiem said:

I recently bought an 8" skyline dob from orion. When I bring it inside for storage should I cap it outside or bring it in and let it warm up first?  What about lenses? I don't want to trap condensation in the OTA. Any advice would be very helpful. I want to use this scope for many years and would just like to know how to best care for it. Thank you. 

leave the caps off and point the open end facing down. give it a few hours then once the moisture has gone recapp it

[Putaendo Patrick]

Must be getting late! I thought I was replying to another post completely

Thanks Faulksy.

[Louis D]

In the winter, I have always capped everything before bringing them inside because there is so little humidity outside during the winter here in Texas but it can still get quite cold.  The moment I bring the optics inside my warm and relatively humid house, everything fogs over and takes an hour or so to warm up and unfog.  By capping my scope outside, the humidity inside the house doesn't have the opportunity to inundate the cold surfaces to form dew.  Same for my eyepieces.  I cap them outside where the humidity is low and seal my airtight case (Pelican type) with cold, dry air inside.

During the summer when it is incredibly humid outdoors (think swamp-like) in Texas, I bring everything indoors uncapped and open to cool down inside my drier, air conditioned house.  After 30 minutes or so to allow for moisture to escape, I cap everything and put it away.

In 20 years of observing, I've never had any sort of fungus issues or mirror coating degradation due to moisture.  It really depends on the difference in moisture between your observation area and your storage area.  Not everyone has dry winters.  Not everyone has humid summers.  Not everyone lives in a house with A/C.  Not everyone lives in a humid house in the winter.  To be on the safe side, you'll probably never have issues if you bring everything inside uncapped and wait for them to acclimate to ambient conditions before capping.  I'm just not a fan of seeing otherwise dry optics suddenly covered in dew that have to be left uncovered for a long time to dry out.

[steppenwolf]

5 hours ago, Putaendo Patrick said:

Must be getting late! I thought I was replying to another post completely

The context of this thread was changed somewhat by the original poster as they have altered the original text so you are not going nuts! The original question was indeed about eyepieces as well!

[faulksy]

5 hours ago, steppenwolf said:

The context of this thread was changed somewhat by the original poster as they have altered the original text so you are not going nuts! The original question was indeed about eyepieces as well!

didn't know that. so its me going mad