About to fit my primary mirror

[SniffTheGlove]

Hi,

Most of my rebuild is nearly done -see other thread.

I would like advice on what I should look out for when fitting a primary mirror into the OTA. This is my FIRST time.

I believe the easiest way would be to have the OTA horizontal, is this correct and is there any pitfalls (apart from "DO NOT DROP THE MIRROR" ) I should look out for.

Thanks

[Doc]

How far have you got?

Have you marked the tube so your holes in the tube match the holes in your mirror cell. I've always considered slots instead of holes, that way you can slide the cell up and down the tube so you could achieve focus with almost any combination of eyepieces, coma correctors, filter wheels, etc.

[SniffTheGlove]

The OTA has 3 equi-spaced holes at the bottom that line up with 3 holes in the mirror wooden base. These currently have screws in them. Then there is the Collimating arms with adjusters.

The previous owner said just line up the screw holes in the base and the OTA and screw in the screws then Collimate.

There is also a large slot 1in high and 6in.long just above where the mirror would be and the previous owner also gave me a folding circle (folds in half) that you can put through the slot, twist the arm and it unfolds inside the OTA. One side is covered in soft tissue which he said was to protect the mirror.

I am going to cover that up that slot and not bother with sticking things on the mirror.

That is the current state of things, is it that easy as the previous owner stated?

[Peter Drew]

I would point the tube slightly upwards, that way you have a bit more control of the weight which tends to try and tip fowards unexpectedly. It is a good idea to cover the mirror with the supplied item, the coating should last longer if you do, but don't put it on if the mirror is still dewed up after use

[callisto]

I prefer to put the base plate with primary fixed flat onto the kitchen table, then lower the OTA slowly onto the plate then scew into place

[Doc]

I prefer to put the base plate with primary fixed flat onto the kitchen table, then lower the OTA slowly onto the plate then scew into place

Thats the way I would do it as well.

[SniffTheGlove]

I prefer to put the base plate with primary fixed flat onto the kitchen table, then lower the OTA slowly onto the plate then scew into place

Ouch, now that would really do my back in. I had to install a pulley in the garage to just help lift the OTS onto the mount and that was difficult with just me doing it, however the OTA is currently in a vertical possition so I could hoist it up and then work off a small stool instead of the kitchen table.