Howie Glatter Parallizer

[janesdsg]

I've got one of these to use with my SW200p but I can't understand the instruction that came with it:

Apply 2" clamp on side opposite 1.25" clamp screw

Please could someone help me out - my lack of understanding is making me feel particularly dense ?

Many thanks

Jane

[westmarch]

Sounds like a malt whisky!

John

[janesdsg]

Maybe a malt whisky might help me understand the instruction ?

[Ally8446]

Your 2" focuser has a screw that holds your eyepiece in. It may even have two. All the instructions are asking is that you put the HGP so that ITS eyepiece fixing screw is directly opposite the original  focuser eyepiece screw. That's probably as clear as mud ?

[Ally8446]

Make sure the gold screw is directly opposite the screw that holds your Parralizer in place in the focuser. 

[janesdsg]

1 minute ago, Ally8446 said:

Your 2" focuser has a screw that holds your eyepiece in. It may even have two. All the instructions are asking is that you put the HGP so that ITS eyepiece fixing screw is directly opposite the original  focuser eyepiece screw. That's probably as clear as mud ?

2 minutes ago, Ally8446 said:

Make sure the gold screw is directly opposite the screw that holds your Parralizer in place in the focuser. 

My focuser has two screws so I should centre the gold HGP screw opposite the small gap between the focuser's screws?

[Ally8446]

Let's say your focuser resembles this one. As you look down on it there is a screw at 12 o'clock and one at 8. Fit the HGP so that the gold screw is at 4. 

At least, that's how I understand it. 

Edited October 31, 2018 by Ally8446
Addition to text

[AdeKing]

7 minutes ago, Ally8446 said:

Let's say your focuser resembles this one. As you look down on it there is a screw at 12 o'clock and one at 8. Fit the HGP so that the gold screw is at 4. 

At least, that's how I understand it. 

Thats how I understood it too.

Ade

[Ally8446]

Just now, AdeKing said:

Thats how I understood it too.

Ade

Great minds think alike Ade mate ?

Or is it. ...fools seldom differ ?

Debatable ?

[janesdsg]

Thanks, both. That's what I was trying to say. The photo is definitely much clearer than my words.

[Ally8446]

Happy to help

[janesdsg]

Much appreciated

[Bullet]

Thread resurrection. If the HGP screw is to be opposite the focuser screw or screws, what if your focuser uses a split brass ring. Would the HGP screw go where the split in the ring is? ie still opposite the screw ( or in my case 2 screws). Thanks

[RT65CB-SWL]

The Hi @Bullet and welcome to SGL. 

My guess after reading the above comments is that when only one set screw is used, there is a small amount of play and movement, therefore it is not parallel/perpendicular. The other set screw whether it is opposite or at 120^o [four o’clock position] it allows it to become as close as possible to perpendicular.

The HoTech SCA laser collimator on the other hand, uses a rotating collar and built in expansion ring or rings and therefore eliminates the use of a set screw or set screws in the eyepiece holder and gets it parallel/perpendicular. This is because the compression ring is expanding and creating equal pressure across the entire surface.

 

Edited August 27, 2023 by RT65CB-SWL

[Jules Tohpipi]

6 hours ago, Bullet said:

Thread resurrection. If the HGP screw is to be opposite the focuser screw or screws, what if your focuser uses a split brass ring. Would the HGP screw go where the split in the ring is? ie still opposite the screw ( or in my case 2 screws). Thanks

I've had a HGP for a good few years. I searched my hard drive for archive stuff on it and found the below. I think the text and diagram was saved direct from the HG website - but I'm not 100% sure. It reads like from the site, though. What to do for a brass split ring is mentioned in the text.

 

How to Use:

            Insert the adapter in the focuser with the slight undercut section of the outside diameter of the adapter opposite to the focuser’s thumb screw to be tightened on it.  Use one, and only one, thumb-screw to tighten the adapter in the focuser.  If the focuser has a brass split ring in the top, make certain that brass split ring is centered on the thumb screw used to tighten down the adapter, with equal lengths of brass ring on either side.

[Note: It is not recommended to use the Parallizer with a Click-lock binder, as these may not tighten down correctly on the outside of the adapter and may defeat the self-alignment feature of the Parallizer.]

Then, insert the eyepiece and tighten the eyepiece down with the single thumb screw in the Parallizer.  This will push the eyepiece against the two edges of the undercut section opposite the thumb screw, registering the eyepiece perfectly in the focuser and reversing the offset in the focuser created by tightening down the adapter.

Just remember to always place the Parallizer thumb screw opposite to the thumb screw in the focuser for proper alignment (registration) within the focuser.

 

Edited August 26, 2023 by Jules Tohpipi

[Bullet]

After reading other threads, I think I've got the idea. The compression of the focuser to  HGP, and HGP to eyepiece should be opposite, which makes sense. However, what if you use/ need a focuser extender?. Then you would have 3 seperate clamp directions. Maybe have them at 120 degrees apart?

[Jules Tohpipi]

1 hour ago, Bullet said:

After reading other threads, I think I've got the idea. The compression of the focuser to  HGP, and HGP to eyepiece should be opposite, which makes sense. However, what if you use/ need a focuser extender?. Then you would have 3 seperate clamp directions. Maybe have them at 120 degrees apart?

The key fundamental point about the HGP is that it's deliberately not perfectly round (both on its outside and inside). The purpose of the machining is to create two contact lines/shoulders both on the inside and outside (shown as contact points in the 2D diagram). Basically he was designing a single item that acted as a V-block for when sitting inside a focuser and a V-block for the inserted eyepiece. Very clever.

Therefore, the correct installation procedure is to ensure the clamping forces are applied ONLY down the centre lines of those two shouldered contact points (lines in the 3D world). Hence the instructions advising only to use one of the focuser's screw clamps. 

To help visualise this, I've added to the diagram solid circles to show what direction the clamping forces should come from, and empty circles to show how the intended contact points should be orientated. Or more simply, the gold Parallizer set screw should be at the 6 o'clock position compared the single screw you use to clamp it in the focuser. If that makes sense.

 

 

Edited August 26, 2023 by Jules Tohpipi

[Bullet]

Thanks for your help. It is much appreciated.  How would I set up if I need a focuser extender?. The focuser clamps onto the extender, and then the extender clamps onto the HGP. Both focuser and extender have split ring compression.  Thanks

[Jules Tohpipi]

I'm not too au fait with brass split rings on focusers but I suppose this part of the HGP instructions points the way. I've added extra words in brackets to clarify what components the instructions are referring to:

"If the focuser has a brass split ring in the top, make certain that brass split ring is centered on the [Focuser's] thumb screw used to tighten down the [HGP], with equal lengths of brass ring on either side."

By focus extender do you mean a Barlow type item (but the focal extender variant) or a focus tube extension? Are the items 2 inch or 1.25"? 

[Bullet]

It's a 2" focus extender Here. 

[Jules Tohpipi]

Great, OK thanks.

Apologies - have edited and removed my reply to ask one further question please.

The two screws on the extension tube and focuser. Is one a clamp only and the other tightens the brass compression ring (similar principle to the Howie Glatter instruction diagrams above)? Or do both screws have an affect on tightening the brass compression ring?

It's hard to tell from the FLO photos unfortunately.

 

 

Edited August 26, 2023 by Jules Tohpipi

[Bullet]

Both screws press on the ring. However, if necessary I can rotate the brass ring and then use just one screw to tighten directly on the parallizer, or rotate the ring and use one screw in the middle of the ring.

Edited August 26, 2023 by Bullet

[Jules Tohpipi]

Perfect, thanks. That's great info. In which case....

1. When putting the Parallizer directly into the focuser
Rotate the brass ring in the focuser and use one screw to tighten directly onto the Parallizer (i.e. not via the ring). Leave the other screw loose. Orientate the Parallizer such that its angled gold screw is at 6 o'clock relative to the focuser screw that's doing the tightening. This is basically the exact recommendation of the Howie Glatter diagram.

2. When using the focus extension tube
Put the extension tube into the focuser - it doesn't matter how the focuser clamps the tube. Use one or both focuser screws if you wish (because it won't affect how the Parallizer seats in the extension tube). Next insert the Parallizer into extension tube. Rotate the extension tube's brass ring and use one screw to tighten directly onto the Parallizer (i.e. not via the ring). Leave the other screw loose (the one that could tighten the ring). Orientate the Parallizer such that its angled gold screw is at 6 o'clock relative to the extension tube screw doing the tightening.

It's excellent that you can rotate the brass compression rings out of the way. It means you clamp the Parallizer exactly the way it was intended.

Edited August 26, 2023 by Jules Tohpipi

[Bullet]

That's great. Thanks again for your help and patience. 

[Jules Tohpipi]

You’re welcome and welcome to SGL!