Where do I fit a heater strap?

[DaveGarland]

Ok so I've finally ordered an Astrozap heating strap but where exactly should I fit it? Do I take the primary mirror out and fit it directly around the edge and out it back? Or does it simply fit around the ota by the mirror?

Thanks for any advice.

Dave.

[Islander]

Neither really. Fitting it to the outside of the tube is just going to introduce thermal currents. It's unusual for a primary to dew up, but if it is then you could try making a dew shield out of a foam camping mat and fit that to the top of the tube.

[DaveGarland]

Well I'm putting it somewhere that's fir sure so I'm wondering where exactly the best place is.

[Islander]

The usual method of heating mirrors is to apply heat to the back of them. Putting it round the outside of the tube is pointless really and TBH i doubt it'll fit around the outside of the mirror and still fit in the clips. A dew shield makes a lot more sense initially.