My dobsonian

[angusw2]

Well I had a go at collimating my 12" Orion Optics dob last night. The first thing I did was check to see if the secondary holder was central, it wasn't. So I started messing with the adjustment screws and ended up taking the whole spider assembly out to get a better look at how the secondary was mounted and how it moved with the adjustment screws. It was at this point I noticed the wires. There is a double electrical wire going into the cylindrical central section behind the secondary mirror that the spider vanes connect to. Anyone have any idea what these might be for?

Anyway I put it all back together and lined everything up and when I had finished it all looked more concentric through the focus see tube than it did before. Miraculously I open the front door and actually saw a few of the Plough stars through a hole in the cloud so I quickly got the scope on the drive and an eyepiece in. With the scope at room temperature and a reasonable magnification the stars were not pin sharp but everything looked symmetrical. After about 10 mins the clouds closed in and I packed away but I'm sure the stars looked more focused and sharper after 10 mins of scope cooling.

Now I need a clear and free evening for a proper test!

[Guest Eddy]

Sounds like a dew heater? Is there a cable with a connector on the end?

[angusw2]

There is a double plug and the wire plugged into that is cut off. I did wonder about a heater, I should have put a pic in my first post but here is one now...

[dawson]

Is it making a ticking noise?

[BAZ]

I would agree that it looks like a dew heater, built into the stem. Check it with a multi meter, if it has some continuity, without shorting to the body, it may be worth connecting it.

A secondary heater on a newt is just whats needed. 

If you get stuck, bring it over, I'll have a look for you. PM me if you need help.