Amazon laser collimation gizmo. Quick review

[GasGiant]

Just a quick note to those maybe deciding on a laser collimator.

I purchased this 

https://www.amazon.co.uk/dp/B07J5WBG4K?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1

Yesterday and it duly arrived this morning. I popped it on my engineers V block to test if it was true and it was bob on. No deflection in the light spot as I rotated it.

I have been collimating my Dob with a cheshire and thought I was pretty accurate with it !! doh, nope. Fitting the laser I could see that It was out by quite a lot!  Not sure how much ' out by quite a lot' affects viewing experience though. 😂

I adjusted both the secondary and primary within a couple of minutes. So easy !!   

The acid test of course is when we have a clear spot enough to look at something ! 

I would recommend this. 

[Orange Smartie]

Thanks for sharing this. Is the collimator itself collimatable? If it did arrive out of alignment, would you be able to tweak it?

Pete

[GasGiant]

No and yes

So around the barrel near the top are 3 equally distanced dips. This I believe is where the setting screws are for the laser. These have been filled in with a soft rubber type substance.  I would imagine during manufacture  the laser is set and the screws covered over.

Potentially you could dig out that rubber and set the screw ?

Edited September 12 by GasGiant

[Clarkey]

3 hours ago, Orange Smartie said:

Is the collimator itself collimatable

Yes, you can remove the cover and collimate the laser. I have the same cheap version, and it was quite a way off. Just remove the gunk with a small screwdriver.

[bosun21]

The laser can be dead centre on the primary mirror mark yet still be miles out of collimation. I found it essential to correctly position the secondary mirror in relation to the focuser draw tube. I use a Concenter(centre) for this task. Once done the laser is ideal for collimation checks before each observing session.

[Mr Spock]

8 hours ago, GasGiant said:

Not sure how much ' out by quite a lot' affects viewing experience though.

A lot! It needs to be spot on to be sharp. The more it's out, the fuzzier everything gets.

[John]

Thanks for that feedback.

I have one of those that came with a 10 inch dob that I bought 2nd hand recently. My example seems to need a bit of collimation though - tested in a similar way to yours, the beam at around 3 metres described a 50mm (approx) circle as I turned the collimator around. Mine needs adjustment !

 

[GasGiant]

Worked a treat.  Was up at 3, looked at Jupiter.  Boom. Spot on  🫡

[Earthserpent]

Thanks for an honest review - I think these collimator gizmos are most susceptible to cheap manufacturing 

[PeterStudz]

The only way I know of making sure collimation is spot on is to do a star test. 

[GasGiant]

24 minutes ago, PeterStudz said:

The only way I know of making sure collimation is spot on is to do a star test. 

How is that performed?

Im not sure I can get better. Everything looks round and sharp 🤔 but sometimes atmospheric conditions will play tricks on you ?

[John]

1 hour ago, PeterStudz said:

The only way I know of making sure collimation is spot on is to do a star test. 

Yep, that's my "acid test" as well.

I tend to find my cheshire more accurate than my lasers when I star test the scope. 

How to star test a telescope | BBC Sky at Night Magazine 

[Mr Spock]

Other methods of collimation work just fine, however, for a long tube, in the dark, you can't beat a laser.
Here's my guide:

 

[GasGiant]

I understand there are two main trains of thought when it comes to collimation.  Cheshire-laser, and it appears there are definitely two camps 😃

 

How more accurate can you get that a thin line of light?   With a Cheshire it seems to me there are more variables to go wrong when lining everything up! 🤔

[Mr Spock]

I can't answer for others, but I find a Cheshire difficult to use. What I have found when I follow the procedure I posted is, my scope is collimated so well, it passes a star test without further intervention.

I t's a great advantage to be up and running in seconds with as little fiddling as possible. Observing time, not fiddle time!