Dew shield help

[emyliano2000]

Hi guys,

I wanna buy an Astrozap Flexible Dew Sield and I'm not sure which one to choose for my Sky-watcher Explorer 200p from all the 8" ones at FLO https://www.firstlightoptics.com/dew-prevention/astrozap-flexible-dew-shield.html

Do I need a notched one? I need to mention that my telrad finder sits against the focuser and the front edge of the OTA.

I'm thinking that I would need the bottom right one from the photo on FLO website (not sure though) but I have no clue which one that is.

 

[astronymonkey]

Hi,

Newtonian reflectors often dont need a dew sheild as the optics are down the tube and are more sheltered so manufacturers might not make them. Have you considered making one from a rolled up foam camping mat and some gaffer tape .... This is often a cheap and effective diy modification which works just as well.

Cheers

[emyliano2000]

6 minutes ago, astronymonkey said:

Hi,

Newtonian reflectors often dont need a dew sheild as the optics are down the tube and are more sheltered so manufacturers might not make them. Have you considered making one from a rolled up foam camping mat and some gaffer tape .... This is often a cheap and effective diy modification which works just as well.

Cheers

I'm planning to use it to prevent some of the stray light going into the tube too.

[acey]

33 minutes ago, emyliano2000 said:

I'm planning to use it to prevent some of the stray light going into the tube too.

Camping mat foam works on that too. The solid tube of a newt acts as a dewshield for the primary, an extension (foam, cardboard, plastic, anything) will provide a bit more shelter for the secondary. As for stray light, look through the focuser in daylight with no eyepiece and you'll see all the places where stray light is affecting the view. If you can see past the top of the tube when looking through the focuser then that part needs to be shielded. Also any internal parts that you can see through the empty focuser could be flocked, or blackened in some other way, to reduce whatever stray light is reaching the eyepiece. If the stray light is light pollution then the best approach is to take the scope somewhere darker: a dewshield will have no useful effect.

[Charic]

I have used camping foam underlay, to add some extension to my scope in order to cut down street light from  entering the scope at certain angles.

Its very cheap and fits the scope like a glove,  is 1.5x the aperture so  about 12" of actual extension beyond the lip of my scope.

As a dew shield alone, little effect if any on the dew, so when it dew's, for me, its time to go in?

[Aaron F Johnson]

A light shield will work and a dew shield too. Used light shields made of plastic painted with flat black auto primer as long as 3' on newts growing up in light polluted Milwaukee WI...Make sure no other light enters elsewhere on the scope weather you can see it or not meaning seal it and erase all reflective surfaces, permanent marker works great and is cheap. If there are gaps make gaskets and paint with black primer. Don't expect fantastic results but even marginal ones can be a noticable and pleasing improvement.

[emyliano2000]

Thank you all for the nice replies but they don't answer my question. If somebody knows which one I should get please let me know.

[Charic]

Your right, we did not answer your question!  but without further  modification, I don't see that Astrozap actually  creates a fitted shield for the Explorer 200, according to their listing?
Might be wrong,  maybe someone does know better,  its just strange that Skywatchers are not catered for/mentioned?