4Tonix Secondary Dew Heater

[Lurcher]

Hi All,

I've been wanting to stop dew collecting on my secondary mirror, and saw a really neat dew heater for secondary heaters on FLO, made by 4Tronix in the UK, which sticks straight onto the back of the mirror and looked an amazing design. The only trouble was the only version available was for an 8" scope, and I needed a larger version for a 12" scope which has a 50mm x 70mm secondary.

I optimistically E-mailed 4Tronix directly (on a Sunday afternoon) to see if they had any plans to make a larger size, and I got a reply within an hour to say sure, if I sent them the measurements they could make one up.

It cost £19.75 plus VAT and postage which I thought was pretty good, and a guy there called Gareth sent me regular E-mails to discuss the shape and build, and to keep me updated on progress. 

(I wasn't sure whether to post this on here or on the supplier review section, as it's both the company and the product which have been great. - Hoping no-one minds that I've copied and pasted this in the supplier review section too).

The heater is now available directly through 4Tronix and hopefully FLO will be listing it too?? The 8" version is of course available through FLO).

I tested it last night with a mini-heat controller purchased from FLO and it was working well, although almost sadly, it was really clear last night for a change, and it wasn't damp at all!! But no doubt given the warmth it was giving off it will work perfectly.

I've attached a couple of photos of it installed.

[NGC 1502]

Excellent 👍 On dewy nights the secondary on my Dob can mist up.  I usually sort that with a 12v dew gun pointed down the focuser, having removed the eyepiece.  Usually lasts 20-30 minutes before a repeat becomes necessary.

But a low heat pad on the back of the secondary would be a longer lasting fix.

Ed.

[Zermelo]

On 12/03/2021 at 09:17, Lurcher said:

almost sadly, it was really clear last night for a change

I think you've hit upon an antidote for the more normal "new-scope-means-clouds-for-a-fortnight" curse.  You've created an astro version of the experiment tying a piece of buttered bread to the back of a cat to see which way it lands.  Expect to see rapidly oscillating cloud cover for a while.