Secondary mirror offset

Didn't I hear that by centering the secondary in a sight tube you are in effect setting an offset towards the primary.

Interms of height above the primary mirror, yes, but I dont think it caters for offsetting the secondary mirror away from the focuser.

I believe you have a premium kendrick laser Dave and did you get a premium jmi EV1 with your obsession

This is the 2" kendrick laser, I got it before these barlowed ones were dreamt up.

The focuser is a JMI DX1, very smooth, I can rotate the laser in this focuser and it remains perfectly collimated, and also rack out the focuser without a change in the beam.
I'm considering getting Howie glatters blug, a recent review of the blug has shown that the it isnt all roses, it can be a loose fit, see this review
www.cloudynights.com/item.php?item_id=1480

How this relates to the topic is that what I found was that cumulative tweaking of the secondary when aligning the laser dot had begun to rotate the secondary,

You'd see this using a Cheshire, would you notice this using a holographic laser?

Its ironic that after the expenditure on the focuser and laser to make sure everything was right, now it takes so short a time to do the entire process (including checking/adjusting centering and rotation) that I almost paradoxically feel I am not getting value for money because I only use this expensive laser for 3 or 4 minute a night when in actual fact this is the very reason I went to the expense, to get accurate collimation that I am confident in down to 3 or 4 minutes

I also find this, once the secondary is sorted in daytime, collimating the primary and tweaking the secondary only takes a few mins.

The secondary mirror of my 16" fell off (luckily the Dob was disassembled) onto a nice padded car seat, a

you're a lucky man, on the obessions they have a string attaching the mirror casing to the spider incase the bolt somehow gives way, you should consider doing the same.

Um... It's actually easier to collimate in daylight - you don't need darkness or stars to do the deed.

Um, I know that, Phil. :lol:
I'm talking about seeing the actual results by star focusing, to see how sharp the images are post-collimation by Cheshire, and to see if further tweaks were possible...we're all looking for that perfect dot.
My idea of purgatory would be to collimate with a Cheshire at night forever.
I found that after I'd used the Cheshire as best I could that laser collimation was almost exactly spot on also.
However, things still constantly shift with my truss dob, even in the top cage, so I'll have the Cheshire out again very soon.