Skywatcher 190MN secondary collimation

[moriniboy]

There seems to be some confusion regarding collimating the secondary on this scope.

My scope has the felt pen circle on the secondary so am I correct in assuming that it should be centred on a cheshires cross hairs, here is a photo of how it currently looks (felt pen mark shown in red)

Looking at the Orion brochure for the same model it indicates centering the secondary to the draw tube as per normal newtonian collimating

The simple question is what's the best way?

[Peter Drew]

I would go "staight on with Orion" 

[perfrej]

There is an extensive thread on collimation of this beast. It is difficult to collimate but it is well worth it. The images that come out of it all have a distinctive refractor feel:

[moriniboy]

Like a good challenge 

[moriniboy]

Decided to go for the felt pen mark in the end.

Completed the collimation yesterday and a star test last night needed a small 1/8th turn on one of the primary adjusters.

Now it has perfect airy rings - result.

Like the way that the primary is held by conventional clips and nylon faced grub screws, nice touch by Skywatcher to stop it from moving (don't overtighten)

However the quality of the steel? that they use in the machine screws leaves something to be desired.

Whilst swapping them over to stainless allen items I encountered 4 that were bent, luckily all were extracted leaving intact threads.

[moriniboy]

I know that this scope has internal baffles but I'm a great fan of flocking to improve contrast. So as the scope was in bits why not I thought.

Here are the obligatory half finished and fully finished photos as a comparison.