Newtonian collimation - by sight vs laser?

[AbsolutelyN]

I'm trying to collimate my 250DPS and am starting visually using a cheshire. 

With the cheshire I can achieve what I think it spot on:

However when I then check with the laser (a 2" HoTech) it always says it's slightly out. Adjust to correct so the laser is correct and I end up with this when I check it with the cheshire:

I know I need to use a star for fine adjustment but as a starting point which one should I trust? I'm worried the cheshire may be out as I need a few 2" extension tubes with it and they are not compression rings etc 

Any thought appreciated.

 

[jetstream]

1 hour ago, AbsolutelyN said:

I'm trying to collimate my 250DPS and am starting visually using a cheshire. 

With the cheshire I can achieve what I think it spot on:

However when I then check with the laser (a 2" HoTech) it always says it's slightly out. Adjust to correct so the laser is correct and I end up with this when I check it with the cheshire:

I know I need to use a star for fine adjustment but as a starting point which one should I trust? I'm worried the cheshire may be out as I need a few 2" extension tubes with it and they are not compression rings etc 

Any thought appreciated.

 

You are referencing primary collimation? if so trust the cheshire unless you have a barlowed laser. You can use the laser instead of the cross hairs for secondary if the laser is very accurate.

For reference: I have a Glatter Laser and TuBlug (barlowed laser device) and find the cheshire is always accurate while the TuBlug can be off a tiny bit at times, depending on me.

Edited September 13, 2020 by jetstream

[AbsolutelyN]

6 hours ago, jetstream said:

You are referencing primary collimation? if so trust the cheshire unless you have a barlowed laser. You can use the laser instead of the cross hairs for secondary if the laser is very accurate.

For reference: I have a Glatter Laser and TuBlug (barlowed laser device) and find the cheshire is always accurate while the TuBlug can be off a tiny bit at times, depending on me.

Thanks Gerry. I aligned with cheshire and it was only slightly off with a star test. Hopefully now spot on. Thanks

[Corpze]

First of all - Is the laser collimator collimated?
Even my hovie glatter laser was off when i first bought it, so it is a good idea to check if it is collimated.
you can do that by rotating the laser in the telescope focuser or make a X-shaped cradle to rotate the laser in, then main point is that when you rotate the laser - the laser dot should not be moving around but stay put.

I have made a youtube video of how to collimate a collimator explaning how to do that.
You can find it here: 

/Daniel, Exo Photography