HoTech laser collimator

[Mike_S]

So i gave my collimation cap away with my old telescope I just sold. I have only ever used that before. 

I would like a laser so I can adjust primary mirror without going back and forth to the focuser.

my questions are:

1. Is there nothing wrong with getting the 1.25” set as it’s cheaper? 

2. Do I need a collimation cap and/or Cheshire with this laser set up as well to confirm? Thinking a laser and £5 collimation cap should be plenty?

 

Edited July 14, 2019 by MSammon

[cletrac1922]

Sam

I use a Saxon 1.25mm Laser Collimator 

Do secondary first, so aligned with dot centre of primary mirror

Then do primary, slightly loosening locking screws

Have target of Collimator, facing down the tube, so can see

I am out a couple of times per month doing presentation in primary schools, scout groups with my club, and very rarely need to re-do collimation

If not transporting your Dob, then be no need to touch once set

John

 

 

 

Edited July 16, 2019 by cletrac1922

[Mike_S]

1 hour ago, cletrac1922 said:

Sam

I use a Saxon 1.25mm Laser Collimator 

Do secondary first, so aligned with dot centre of primary mirror

Then do primary, slightly loosening locking screws

Have target of Collimator, facing down the tube, so can see

I am out a couple of times per month doing presentation in primary schools, scout groups with my club, and very rarely need to re-do collimation

If not transporting your Dob, then be no need to touch once set

John

 

 

 

Thanks, do you check it with a collimation cap or a Cheshire? 

[wookie1965]

Have a read through this it will help you.

http://www.smartavtweaks.com/RVBL.html

[Mike_S]

30 minutes ago, wookie1965 said:

Have a read through this it will help you.

http://www.smartavtweaks.com/RVBL.html

I was looking at the howie glatter and tublug but so expensive. The Hotech one is meant to be self centering? I have a cheap Barlow I can try with it anyway.

Edited July 15, 2019 by MSammon

[wookie1965]

I have heard good things about the Hotech ones when I had a Reflector I bought a cheap laser not realising it was out as much as I could I could not collimate it, foolish me bought another collimated that but for £70 for the pair could of bought a Hotech one.

[John]

I use a simple cheshire eyepiece with my OO 12 F/5.3 dob. Dead simple and spot on. I have owned quite expensive laser units (and cheaper ones) but the cheshire has proved  the most accurate when I've star tested the collimated scope. So it's one area that I don't have many £'s invested in !

The locking screws on the OO primary cell should be left loose by the way, unless you are transporting the scope (ie: in a car or similar). The locking screws themselves can alter the collimation which is frustrating once you have it set up. So I leave mine loose.

 

 

[Ricochet]

I think that the best tool for positioning the secondary under the focuser and aligning it with the primary is a sight tube. Most modern Cheshires are combined Cheshires and sight tubes, and the red FLO Cheshire is an excellent and accurately machined example. For aligning the primary the easiest accurate tool is the barlowed laser. You want a laser that you can collimate with a 45° face and a decent barlow that is accurately machined enough not to tilt in the focuser. I also use a small Cheshire with the sight tube crosshairs removed to check the primary (I can also use this in place of the barlowed laser but it requires more practice).

With regards to the Hotech, I did once buy one, but returned it to the seller because the self centring and/or collimation was off and it did not give repeatable results. I was also unimpressed with the quality of the laser image it projected. If you are going to buy an expensive laser for alignment of the secondary I would go for a Glatter option.

[Littleguy80]

I personally like my Cheshire. Takes me one to two minutes to collimate the primary at the beginning of a session. Easily done with a red torch in the dark. No batteries required. I’ve always been put off by the fact that laser collimaters require collimating themselves. The pictures below isn’t the best but gives an idea of easy it is to see if you’re properly collimated. Might need to zoom in a little. There are plenty of better example pictures on here.

[jetstream]

16 hours ago, Littleguy80 said:

I personally like my Cheshire. Takes me one to two minutes to collimate the primary at the beginning of a session. Easily done with a red torch in the dark. No batteries required. I’ve always been put off by the fact that laser collimaters require collimating themselves. The pictures below isn’t the best but gives an idea of easy it is to see if you’re properly collimated. Might need to zoom in a little. There are plenty of better example pictures on here.

Neil, which ones are the crosshairs to line the secondary up? the thick ones or thin ones?

[jetstream]

On 14/07/2019 at 18:15, MSammon said:

Thinking a laser and £5 collimation cap should be plenty?

Some cheshire/sight tube combination tools are very "busy" visually, adding confusion. I use a similar (cheaper plastic SW) version of this refractor collimator (newts too) in the f5 Heritage 130 for primary collimation with accurate results. I also use a cheap Celestron combination tool- like @John possibly that is dead on.

[John]

19 minutes ago, jetstream said:

Some cheshire/sight tube combination tools are very "busy" visually, adding confusion. I use a similar (cheaper plastic SW) version of this refractor collimator (newts too) in the f5 Heritage 130 for primary collimation with accurate results. I also use a cheap Celestron combination tool- like @John possibly that is dead on.

Yes, thats the one that I use Gerry. I got mine free with a Skywatcher dob a few years back.

 

[jetstream]

1 minute ago, John said:

Yes, thats the one that I use Gerry. I got mine free with a Skywatcher dob a few years back.

I thought it might be, I'm amazed at the accuracy of these John, as checked against more expensive tools.

[Mike_S]

found it here. I don't know why it says it's for a refractor and the reflector one is longer?
https://www.365astronomy.com/Collimating-Eyepiece-for-Refractor-Telescopes-Short-Collimator.html

[jetstream]

10 minutes ago, MSammon said:

found it here. I don't know why it says it's for a refractor and the reflector one is longer?
https://www.365astronomy.com/Collimating-Eyepiece-for-Refractor-Telescopes-Short-Collimator.html

This tool only does the primary.

A sight tube is also needed, which has a longer tube to put the crosshairs down a bit so you can see them,-a combination tool- has both a sight tube and cheshire built in- they can be confusing for people.

When adjusting sec with a combo tool, cover the cut out...IMHO. It reduces visual confusion.

[Mike_S]

Christ I thought it was easy enough with just a collimation cap haha. I ideally would like a laser so I don't have to go back and forth from the primary. Saving money for a bit. Will have to get something soon though as I gave away my collimation cap lol

[jetstream]

41 minutes ago, MSammon said:

Christ I thought it was easy enough with just a collimation cap haha. I ideally would like a laser so I don't have to go back and forth from the primary. Saving money for a bit. Will have to get something soon though as I gave away my collimation cap lol

You need the combo tool first, for the sight tube feature, to center the sec under the focuser which will automatically give proper offset.

You can then use the laser to line up the sec to primary- put the laser dot in the donut.

You can then use a BARLOWED laser in a Hotech cut out collimator or Glatters TuBlug. This image is from wookies great link.

PS- the combo tool will do all you need... once you de confuse what you see through it IMHO.

http://www.smartavtweaks.com/RVBL.html

Edited July 16, 2019 by jetstream

[Mike_S]

4 minutes ago, jetstream said:

You need the combo tool first, for the sight tube feature, to center the sec under the focuser which will automatically give proper offset.

You can then use the laser to line up the sec to primary- put the laser dot in the donut.

You can then use a BARLOWED laser in a Hotech cut out collimator or Glatters TuBlug. This image is from wookies great link.

PS- the combo tool will do all you need... once you de confuse what you see through it IMHO.

http://www.smartavtweaks.com/RVBL.html

Sorry have you got a link to the combo tool I'm confused? Does the HoTech not come with everything for £85? Which one is that in the link?

[jetstream]

Buy this, not the more expensive red one. You can accurately collimate with it.

https://www.firstlightoptics.com/other-collimation-tools/astro-essentials-cheshire-collimating-eyepiece.html

[jetstream]

The laser in the link is an Orion I think

https://www.telescope.com/Orion-LaserMate-Deluxe-II-Telescope-Laser-Collimator/productVariantId/0/p/102109.uts

[jetstream]

@MSammon you might want to seriously consider a TuBlug from FLO down the road. The combo tool will be good to start with IMHO.

[Mike_S]

5 minutes ago, jetstream said:

@MSammon you might want to seriously consider a TuBlug from FLO down the road. The combo tool will be good to start with IMHO.

So if I get a TuBlug, which i was looking at earlier. Do I just get that and any laser or do I need the Howie Glatter laser? Is the Tublug an alternative to the combo tool? Really sorry for all the questions. 

[cletrac1922]

1 hour ago, MSammon said:

Sorry have you got a link to the combo tool I'm confused? Does the HoTech not come with everything for £85? Which one is that in the link?

 

Saxon Laser Collimator does similar

First align secondary to dot centre of primary

Then align primary, until image on target disappears, centre of target

Be sure does not move off centre when securing locking screws of primary

Attached shows fitted with 2" adapter

John

Edited July 16, 2019 by cletrac1922

[John]

I've had my fill of cheap and expensive lasers over the years. I've collimated the lasers carefully before use as well (even the expensive ones were not that accurate). I've had expensive cheshires and sight tubes too and a Tectron set. I've tried the barlowed laser approach, which was the best of the laser-assisted methods I think but I'm now happy to rely on the cheap plastic shorty cheshire / sight tube combo. It works, it's quick, and it's accurate. Job done

[jetstream]

1 hour ago, MSammon said:

So if I get a TuBlug, which i was looking at earlier. Do I just get that and any laser or do I need the Howie Glatter laser? Is the Tublug an alternative to the combo tool? Really sorry for all the questions. 

Perfectly fine, sorry to disappear for a bit but T bone steaks went on sale and the BBQ just did a fantastic job!lol!

Any laser will work- but the beam can't wobble around if you rotate it- Glatters are VG as are Randy's at Astrosystems in the States.

The laser inserts into the TuBlug and is then an extremely effective barlowed laser with a cutout screen...

A sight tube is needed to center the sec under the focuser accurately, so yes the combo tool (or stand alone sight tube) is needed. All this sounds daunting but it is very very easy....

Edited July 17, 2019 by jetstream