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Jimtheslim

Is wiping the dew from your Telrad the done thing?

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I was using my Telrad for the first time the other night (despite buying it several months ago when we had no decent dark skies). It dewed up almost instantly. I am looking to make a little shield for it, but was also wondering if wiping it with a clean cloth or tissue is of any use? I am guessing the glass isn't exactly precision engineered  given the price of the item, but wouldn't want to do any damage. Oh and Telrads absolutely rock BTW!

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Yes. Wipe away. When I am being too lazy to hook up some power for the dew heater, I often use my thumb. Something absorbent would work better....

Wiring a resistor under the glass works really well if you have a 12v power supply and a dew controller. Costs a couple of pounds. Add another couple of pounds to make a simple controller (although simple controllers are fairly cheap).

Paul

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yeah, no worries doing that at all. I replaced my screens with perspex and have one in my pocket warming and swap over if they dew up.

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I don't think it would do any harm to the telrad 'optics' but it's likely to leave them smeary and difficult to use. If you have a trawl through the DIY section you'll see that some folks have made dew heaters from small resistors and basic circuitry kit from Maplin. I use a hair drier as i have 240v power available to me in my garden obsy.  

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Ok. The prize goes to Shane for ' best common sense solution'. The only point that I would take issue with is the "if" word. They "will" dew up. They always dew up!

Does this work with secondaries as well???

Paul

Edited by Paul73

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12 minutes ago, Moonshane said:

yeah, no worries doing that at all. I replaced my screens with perspex and have one in my pocket warming and swap over if they dew up.

this I like, sounds like a great system!

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You have found the perfect dew magnet, I have had mine dew up as soon as I get settled for an evening's use. For a quick fix an old piece of towelling thrown over the Telrad works a treat. It may not look as elegant as some other solutions but hey who's looking in the dark.

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Is it worth getting/making a dew shield for telrads or is better to just use a warmth generating system like propriety dew heaters or their diy alternatives like  bands of resistors or the use of an hairdrier to demist the dew/prevent it forming in the first place?

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Try whatever is least hastle first! If it works well enough, stick with it!

I went down the heating route as I already had a dew heater on the secondary.

Paul

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tmp_20779-DSC_0161-598157637.JPG

Not easy to see on this pic (best one on my phone at the moment). Got a heater by AstroZap that inserts behind the screen, works a treat. Wiping with fingers will work fine, as well.  :happy11:

If I could solder without causing mayhem I would gladly go for a DIY job. Perhaps time to learn.

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Think I will invest in dew heaters this year. Reason being that unless you have a method of dew removal once it forms on your optics (and it will) the only thing to do is pack up and go home

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6 hours ago, Moonshane said:

yeah, no worries doing that at all. I replaced my screens with perspex and have one in my pocket warming and swap over if they dew up.

I just take the glass out and wipe it on my shirt :) . 

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16 hours ago, iPeace said:

tmp_20779-DSC_0161-598157637.JPG

Not easy to see on this pic (best one on my phone at the moment). Got a heater by AstroZap that inserts behind the screen, works a treat. Wiping with fingers will work fine, as well.  :happy11:

If I could solder without causing mayhem I would gladly go for a DIY job. Perhaps time to learn.

This: https://www.soselectronic.com/products/zd-99  is a very nice and simple soldering station with changeasble tips and temp regulated, so you won't burn thing while learning.

The soldering pistols have a far too big tip and get too hot. Stay away from those, especially if you want to work on small connectors and prints.
Use a good leadfree multicore solder and you will be an expert in no time! (after burning your fingers a couple of times :headbang:)

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On ‎10‎/‎4‎/‎2016 at 11:24, Moonshane said:

yeah, no worries doing that at all. I replaced my screens with perspex and have one in my pocket warming and swap over if they dew up.

how do you remove the original screen? Mine seems welded in place

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I think it was held in by silicone or similar. I seem to remember a decent amount of pullage and it cam out readily enough. just be as firm and as gentle as necessary. if in doubt, just keep wiping and leave it. :icon_biggrin:

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Just a thought...could you not use rain-x on the screen. Not sure how effective it would be.

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I wipe mine with a fine micro cloth such as what you have to wipe glasses or that comes with binoculars, cameras etc. 

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2 hours ago, scarp15 said:

I wipe mine with a fine micro cloth such as what you have to wipe glasses or that comes with binoculars, cameras etc. 

Nice, I have a few of those that the wife bought in a cheap multi-pack...I never did trust using them for eyepieces so I will use those for now

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On 10/4/2016 at 11:45, iPeace said:

tmp_20779-DSC_0161-598157637.JPG

Not easy to see on this pic (best one on my phone at the moment). Got a heater by AstroZap that inserts behind the screen, works a treat. Wiping with fingers will work fine, as well.  :happy11:

If I could solder without causing mayhem I would gladly go for a DIY job. Perhaps time to learn.

Is there a telescope in there somewhere??

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1 hour ago, k9wis said:

Is there a telescope in there somewhere??

I tend to lose track myself.

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