Does anyone know where to buy 40mm fans that don't vibrate too much?
Just received some brushless fans in the post. I was planning to use them to clear the boundary layer in my dob using a suspended wire mount in front of the mirror, but I can feel the vibrations when it is running and I worry that they might transfer those vibrations to the telescope and ruin high power views.
I figure not all fans are created equal, but I wonder how you even find them. 'noise' in the specs I think refers to electrical noise, I believe.
I have used small scroll fans that are vibration free in my 10" Newt to move boundary air. I bought them off ebay for something like $2 each from China. They are like the little fans used in laptops.
Use 5 volts to a 12 v fan and suspend them on a 'spider' of fishing nylon. I just used the corner holes of the muffin fan housing to make a 4 pointed star to 4 screws in the back of the OTA mirror support. Nylon takes up any vibration easily and slow fan speed means there aren't any to begin with.
Another happy user of Noctua fans. They also come with anti-vibration rubber washer and rubber mountings (maybe not all models). But not cheap, as Matt said.
sunon maglev are pretty good - original equipment in my Starlight Express astro cam, so they have minimal vibration.
I bought a couple of 40mm ones from Altronics last year - or try ebay.