Why would my collimating have differing results?

[I have seen amazing things]

https://i.imgur.com/WXJQ9gf.jpg

https://i.imgur.com/bb0rRTZ.jpg

https://i.imgur.com/Fm0634u.jpg

See the images attached. Bought a visual collimating cap just as it was cheap and light and went about visually collimating my 8inch dob. I was quite surprised how far off centre my secondary mirror was! Anyway, all looks great and perfectly collimated.  See  2nd image. But and this is the bit I am struggling with...when I put my laser collimating tool in, it appears to be miles off! Yet visually its perfect. Which one is correct?? Why do you think they are different results? I am confused Thanks. 

[wormix]

Laser Collimators can need collimating themselves helpfully, at the very least you need to ensure they are seated squarely in the focuser or it can throw things right off

Edited October 12, 2019 by wormix

[wormix]

Take a look here for some tips;  

 

[wookie1965]

I've had 2 laser collimators the first although I dug the gunge out where the screws were and could adjust it it never would collimate. I threw it in the bin got a new one that was miles out but managed get that collimated.

So don't rely on the laser collimator I only used it to do the Barlow method.

I used a Cheshire/Sight tube.

[I have seen amazing things]

51 minutes ago, wookie1965 said:

 

I used a Cheshire/Sight tube.

Fair enough, Thanks. I am mistrusting the laser now and trusting my eyeball! Just bought a cheshire from FLO & see how I get on with that! 

[wookie1965]

You can put a Barlow in then the laser and can check it that way you will see the primary mirror and can centre it doesn't matter if the laser is out a bit.

[wookie1965]

https://stargazerslounge.com/topic/46941-barlowed-laser-collimation-method/

[Ben the Ignorant]

A slightly defocused star at high power tells the truth about collimation. A motionless light source is more convenient so use Polaris or a a pinhole in aluminum foil. When the defocus rings are concentric there is no doubt.

[pregulla]

Try rotating the laser or the cap inside the focuser. If it changes how your collimation looks you know they are off.