Newtonian cooling fans

[bottletopburly]

Decided to put  cooling fans on my newtonians a 200pds and a 130pds ,used a 120mm on the 200 and a 80mm on the 130pds ,i used, Be Quite silent Wings2 fans they  use rifle bearings and are so quite German made, i did the 200 first and was impressed with this make so ordered the same make for the 130 pds it comes with a lead with four wires but only needed neg ang pos so snipped other two out ,  made a disc from plastic and cut out around collimation screws on primary then used velcro to attach to OTA  fitted a 2.1mm  dc socket on to the disc then bought a usb lead  to 2.1mm barrel though i may fit another 2.1mm socket on my power box and use 12v either way it works ,i used a dimmer on the 200pds but it doesnt need it and wouldn't use it again but its fitted now so will leave in place. 

[Tim]

Looks very  neat

Is it pulling down through or pushing up the air?

[Charic]

I use a Flexi hose from a tumble dryer and hook that over the open focuser. The other end lies on the ground with a PC fan inside the opening using a 9V PP3 type battery, the type you'll find in a smoke alarm.

Air is drawn though the base of the scope around the mirror, and exits though the Flexi-hose, and some no doubt exiting via the small 2" filter cap that I remove from the OTA end cap.

I would  really like to have two fans, sucking/blowing ACROSS the face of my primary mirror, but not wanting to drill just yet, I'm quite happy with the present setup I use.

I feel there is a definitely an improvement to the waiting time, prior to using higher magnification.

 

[bottletopburly]

10 minutes ago, Tim said:

Looks very  neat

Is it pulling down through or pushing up the air?

pushing air up ota ,because it is velcroed onto ota base little air lost and forces around mirror 

[bottletopburly]

7 minutes ago, Charic said:

I use a Flexi hose from a tumble dryer and hook that over the open focuser. The other end lies on the ground with a PC fan inside the opening using a 9V PP3 type battery, the type you'll find in a smoke alarm.

Air is drawn though the base of the scope around the mirror, and exits though the Flexi-hose, and some no doubt exiting via the small 2" filter cap that I remove from the OTA end cap.

I would  really like to have two fans, sucking/blowing ACROSS the face of my primary mirror, but not wanting to drill just yet, I'm quite happy with the present setup I use.

I feel there is a definitely an improvement to the waiting time, prior to using higher magnification.

 

im sure  one fan will be sufficient ,i will leave tube cap on and focuser open to cool down ,then leave fan on during operation ,