Dew heater strip

[Kenneth Spackman]

Hi. 

I have a sw 127mm maksutov telescope and have been getting up early mornings to view the planets however, the dew is problematic so purchased a dew sheild to good effect. My main worry is the colder winter nights and currently looking at purchasing a dew heater strip but cannot find any information in regards to switching the dew heater strip on before taking the scope outside and do you leave it switched on when bringing it back indoors. I would kindly appreciate any advice please. 

[Elp]

It helps if it's on prior to dew forming as it'll allow the heat to conduct into the glass, but you can switch it on whilst outdoors and leave it for a bit to warm up. If you bring a cold scope into warmer indoors then by all means keep it on, I tend to leave the scope in cooler indoor settings without the dew straps on unless it's freezing temps outside and allow them to equalise naturally.

Edited July 10, 2023 by Elp

[Kenneth Spackman]

Hi Elp

Thank you for your reply. I wasn't to sure. Would you put the dust cap back on with dew heatstrip on if I bring the scope back in from the cold to a warm house or leave it off until scope equalisers. 

[Elp]

I'd leave to off as any moisture might condense if covered, once dry you can then blow the front off with a manual air bulb blower if it's a glass objective then cover up.

[Kenneth Spackman]

Hi Elp

Thank you so much. 

I am more educated now and appreciate your advice and will definitely put it into practice. 

Take care 

[Elp]

Try not to wipe the glass, if there's anything potentially abrasive on it it can affect the coating.

[Kenneth Spackman]

Hi Elp

Thank you kindly. I have just finished reading up on this and your advice is strongly recommended, again many thanks. 

[bosun21]

You might want to buy a heated dew shield as opposed to a dew band as your existing dew shield will cover the position of the front meniscus lens where the dew band needs to go. I don’t know if placing the band further back will have the same effect. On bringing the scope indoors I used to remove the heaters and cap and point the scope downwards until the morning. Then just blow the meniscus lens with an air blower and replace the cap.

[Kenneth Spackman]

Hi Bosun21

Thank you for your reply 

I have been looking at the all in one heated dew sheild on FLO and will give it some thought as it makes a lot of sense and I noted good reviews from people using them. I have been religiously blowing front lens prior and after but will also try with scope pointing downwards. Thank you for the advice. 

[bosun21]

You point it downwards to ensure that any moisture doesn’t ingress into the optics. I used to use the heated dew shield and it kept the dew at bay even on the worst nights. It will also prevent the meniscus lens from freezing over in winter.

[Kenneth Spackman]

That's been my biggest worry using the mak in winter and heavy dew nights/ early mornings this summer , but I feel a lot more confident using either a heated dew strip or heated dew sheild and grateful for yours and Elp replies. Thank you both. 

Take care by