Boundary layer control

[Spec-Chum]

I've been reading about this and I've seen a Mauro da Lio baffle mentioned and cross flow fans etc. All very interesting.

Has anyone tried with scope as small as an 8"?

Is it worth it?

What method did you use (baffle, xflow fans, fan at back?)

I've got a huge 250mm PC fan waiting to get the call of duty

[Astro_Baby]

I have an 8" scope, i used quite a large fan with low vibration characteristics. The fan has a speed controller on a pendant.

The fan blows air into the scope.

At high speeds the fan can cause the front of the primary to be blow clear die to the turbulence of the airflow in the tube. I tested this by introducing some smoke into the tube so I could see what happened. At high speed the fan creates no vibration but generally I run it flat out for a while to cool the scope and then turn it off. Sometimes I will let it run at a slower speed for a while and sometimes I give the fan a quick burst when using high power which I sometimes find steadies the views a bit.

Cant recall thefan size but its about 6". .............i deliberately installed a larger than required fan because it would mean more air being pushed in at lower revs. The back of the scope is fully covered so that air deflecting off the rea of temirror doesnt come out the back end...all air is forced up the tube.

Was it worth it ? Probably for cooling the scope but in the UK conditions are usually so abysmal the effect of boundary layer is never likley to be a big problem is my guess, your at far more hazard from just plain unsteady seeing.

[Spec-Chum]

Exactly what I was looking for, thanks AB.

Steadier seeing at high mag is always useful