Minimum Distance away From SCT For Collimating With Artificial Star

[DavidM61]

I am considering purchasing an artificial star to collimate my Meade LX90 8" SCT scope with. I have read conflicting reports around the minimum distance that the artificial star needs to be from the scope. Some suggest that you need to be at least 100' away from it, others that for collimation only, you can do it at the minimum focusing distance of the scope - which in the case of the Meade LX90 8" is around 25'.
Can anyone confirm which version is correct? At least 100' or at the minimum focusing distance, 25'? 
Many thanks in advance.

[RT65CB-SWL]

Hi @DavidM61

I would go for the 100' [or more] option. 

Out of interest, which brand of artificial star are you/did you purchase?

I have the Hubble Optics one... https://www.hubble-optics.com/artificial-stars.html and ordered mine directly from them.

So I do not lose the small mask, I place small vinyl pipe/tube end cap [just so happens to be 1.25"] over the end, when it is in storage.