Star Test

[ausastronomer (John Bambury)]

Originally Posted by slice of heaven

The baffle above your primary :Was it for masking the edge or reducing the boundary layer or something else ?

Slice,

Its an annular light baffle made from 10mm plywood. It doesn't mask the primary at all.

CS-John B

[Orion]

Interesting idea John. Would the pump have to run continuous or do you tune it on for a few minutes? I've used these pumps before and some tend to be a bit on the noisy side. Love to see how it turns out.

[[1ponders] (Paul)]

Not being a newt user I may be way out here, but what about birds temp modifications to his mirror? Wouldn't that work as well. If the problem is turbulance created by the temperature differentail of the mirror boundary layer and the OTA air column, wouldn't chilling the mirror help to releave this problem???

[slice of heaven]

Yes your right Paul, Birds setup is ideal, but its out of my league. I'm looking for a simple way of removing the layer, something low tech.The fan is already fitted so I'd like to incorporate that in removing the layer. If that fails then something like Johns method might have to be used, but like Orion stated the air pumps are noisy and they vibrate .

[ausastronomer (John Bambury)]

Originally Posted by Orion

Interesting idea John. Would the pump have to run continuous or do you tune it on for a few minutes? I've used these pumps before and some tend to be a bit on the noisy side. Love to see how it turns out.

Ed,

Your right, the pump is a little noisy, and it vibrates a little. My intention was to only run the pump for 15 mins or so prior to observing whilst I also had the cooling fan blowing onto the primary and up the tube. I think in conjunction with the fan I will only have to "stir the air" above the mirror for a short period to get rid of the boundary layer and tube currents. I have mounted the pump firmly to the side of the rocker box so vibration and noise should be dampened a little by this.

CS-John B

[[1ponders] (Paul)]

I know you guys with your newts don't suffer as much from dew problems as us lens users, but if your game enough to put a larger hole in the side of the tube, how about a 12V hair dryer. Use just the fan setting initially to help remove the boundary and if it starts to fog up during the night, switch to heating to remove dew. ?????

[Orion]

I seen a set up for a trust tube telescope which a small fan was suspended from the corners of the mirror box above the mirror with thin cable. The positive and negative wires for the fan ran along two of the cables to a power source. The cables coincided with the diagonal veins.

[bytor666]

http://www.cloudynights.com/ubbthrea.../o/all/fpart/1 For Optimum performance..check out this thread. this next thread is great too..check it out..it'll help immensely. http://www.cloudynights.com/ubbthrea.../o/all/fpart/1
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Mark
12" Gso Scope