Hotech SCA Laser Collimator

[tomato]

Having only owned and used refractors for a number of years, I wasn't looking forward to collimating a recently acquired 16" SW Dobsonian. However, @Tomatobro loaned me his Hotech SCA Laser Collimator and after using it I felt compelled to write this review. 

The expanding rubber o ring arrangement ensures the instrument is centrally aligned in the focuser and achieving precise alignment of the primary mirror spot was straightforward, I was impressed with how when precisely aligned, the laser projected some thin illuminated cross hairs across the surface of the primary. 

Then onto primary adjustment, again the projected cross hairs on the collimator target made this a quick, straightforward process. When I think back to the late 1980's when I used to try and collimate my F4 Schmidt Newtonian without the aid of a device such as the Hotech, I really appreciate this technological advance. 

Highly recommended.

[RT65CB-SWL]

I have the Hotech SCA too... and the Baader collimator.

Both are excellent tools for the job!  

[Corpze]

Hi, I am just corious if you have tried to clamped and "re-clamped" the collimator and got the same result - I had this 2" Hotech collimator and did not get consistent results.

I believe this is due the rubber rings that might some how shift the clamping. (having a starlight feathertouch focuser, I really hope that the focuser is not the problem)

I realy like the idea of the clamping method but in my opinion, it falls short over its non consistent clamping, making the laser dot move from one clamping to another.

/Daniel

[tomato]

I have to adjust the collimation every time I use the scope as it gets a bumpy ride from the garage to the back garden. I slacken the o rings completely then tighten them up in the focuser each time, then carry out the collimation process. This has given me excellent star shapes (but visual only) every session so I have to conclude the Collimator is ending up central in the focuser each time.

[Corpze]

21 hours ago, tomato said:

I have to adjust the collimation every time I use the scope as it gets a bumpy ride from the garage to the back garden. I slacken the o rings completely then tighten them up in the focuser each time, then carry out the collimation process. This has given me excellent star shapes (but visual only) every session so I have to conclude the Collimator is ending up central in the focuser each time.

Well thats for sure, i need to do the same thing with my astronomy clubs 12" dobs every singel time i look at them 😛

Have you tried to collimate your scope (with the laser hitting the center dot perfectly) - released the collimator - and then re-clamped the collimator and looked at where the laser hits the center dot? Thats where I had prolems with my hotech - the second time i tightened the collimator, the laser dot wasn't in the center dot.

I tried this many times and got very unconsistent results, unfortunately, because i loved how easy it was to use.

/Daniel

[tomato]

No, I will try that, but I do find the collimation changes over time anyway on the 16”, it will shortly receive an upgrade by having some fans fitted to the base of the mirror cell.

I store it in the garage when not in use and at this time of year the garage door sees all of the afternoon sun so the Dob must be at 10-15 deg above ambient when I first take it out to use, not good!