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Howie Glatter SI-BARRAT Holographic collmater attachment questions.

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#1 Tom Gwilym

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Posted 22 July 2019 - 03:30 PM

Howie Glatter collimation question: I bought the holographic attachment for our collimater and tried it out. I thought it was the one that had the grid pattern that I ordered from OPT. Testing it out, I get kind of a "clipped" circle when projecting it at shown in the photos. I did put it on the scope and aimed at the wall (It's a 16 inch RC scope) and I basically got the same pattern, but larger of course.   I did request the "grid" pattern but they sent me an "SI-Barrat" attachment.  I'm ok with that a long as I can get it working.  I think the "BAR" means Barlow and looked it up and it does say it's a barlowed part. 

I'm confused how to use this thing. Did I get the wrong part? Is this what I should see? I'm not sure how I use this thing since I don't seem to see anything symmetrical in the image.

 

Help!

Tom

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#2 havasman

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Posted 22 July 2019 - 03:39 PM

I have the holographic grid projection device I got years ago and its projected pattern is nothing like what you have there. The device creates a clear and regular grid of red laser light.

 

I use it only to align the secondary when I have taken a scope apart and, with some effort, it works like a charm.


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#3 Tom Gwilym

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Posted 22 July 2019 - 07:06 PM

It's almost like there is some protective plastic on the lens or something.  I'll have to look at it closer and see if I'm just doing something dumb.  But I sure don't see any kind of pattern in this 'blob' of laser.

 

Tom

I have the holographic grid projection device I got years ago and its projected pattern is nothing like what you have there. The device creates a clear and regular grid of red laser light.

 

I use it only to align the secondary when I have taken a scope apart and, with some effort, it works like a charm.



#4 Jon Isaacs

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Posted 22 July 2019 - 10:58 PM

Tom:

To my eye, that looks like the laser without the aperture.  Have you looked to see if there is actually anything in holographic adapter?

 

What I an offer:

 

I used to use the Self-Barlow attachment to collimate my Newtonians.  I do a lot of observing and eventually the threads in my laser became worn so I sent it to Howie to see what he could do.  When it came back, he had given me a second holographic adapter.  

 

I have my original holographic adapter which I would be happy to loan to you but I believe those were matched to individual lasers whereas the later version would work with any HG laser. Still, it might be worth a try.  

 

If you are interested, send me a PM.

 

Jon


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#5 Tom Gwilym

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Posted 22 July 2019 - 11:34 PM

Hi Jon,

I've only given it a quick try so far (it's a club telescope, but fortunately only a 5 minute drive!).  I did try it without the attachment and I got the expected tiny, sharp point laser dot.  When I put on the holographic thing, I got kind of a wider circle, but with two sides of the circle flattened.  The photo does show it pretty well despite the bright exposure.  Then on one side, there is that "reflection" looking junk.  When I put it on the scope, I did get an image on the wall, but just looked like a big version of the same thing.  Just to check, I rotated the collimater and sure enough, the image rotated.  

I'm wondering if they sent the wrong thing, defective, warped, or possibly doing something dumb! 

I may go over tomorrow night and play with the scope and try it out again. Currently working with my own observatory right now - got plenty of scopes here to play with.

Thanks for the loaning offer, I'll get back to you after I give it another try and see what I can figure out.  I may take you up on that, but want to explore this a little more.

 

Tom

https://www.doorastronomy.org/

 

Tom:

To my eye, that looks like the laser without the aperture.  Have you looked to see if there is actually anything in holographic adapter?

 

What I an offer:

 

I used to use the Self-Barlow attachment to collimate my Newtonians.  I do a lot of observing and eventually the threads in my laser became worn so I sent it to Howie to see what he could do.  When it came back, he had given me a second holographic adapter.  

 

I have my original holographic adapter which I would be happy to loan to you but I believe those were matched to individual lasers whereas the later version would work with any HG laser. Still, it might be worth a try.  

 

If you are interested, send me a PM.

 

Jon



#6 Jon Isaacs

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Posted 23 July 2019 - 12:38 AM

I've only given it a quick try so far (it's a club telescope, but fortunately only a 5 minute drive!).  I did try it without the attachment and I got the expected tiny, sharp point laser dot.

 

 

How dark was it when you tried the attachment.  It has to be quite dark to see the grid.  If you look at the attachment, can you see anything in the aperture?

 

What does the attachment look like?  

 

Jon


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#7 Tom Gwilym

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Posted 23 July 2019 - 01:40 AM

Not super dark, it was dusk and had some light coming through the observatory dome, but sure wasn't any grid pattern. 

It's one like this.https://www.cameraco...-collimato.html

I wonder if I need to put a barlow in front of it?   "The Howie Glatter Barlow Laser Collimator Barlow Attachment diverges the beam just behind your barlow lens for accurate alignment."

 

Tom

 

How dark was it when you tried the attachment.  It has to be quite dark to see the grid.  If you look at the attachment, can you see anything in the aperture?

 

What does the attachment look like?  

 

Jon



#8 Jon Isaacs

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Posted 23 July 2019 - 01:44 AM

Tom:

 

A Barlow would not be helpful.  I believe that is the later version of the Holographic attachment.  Go into a dark room and see if you can see a pattern on the wall about 4 feet away.

 

Jon



#9 Vic Menard

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Posted 23 July 2019 - 09:56 AM

Tom:

 

A Barlow would not be helpful.  I believe that is the later version of the Holographic attachment.  Go into a dark room and see if you can see a pattern on the wall about 4 feet away.

 

Jon

SI-BARATT = Starlight Instruments Barlow Attachment. The Barlow Attachment magnifies the normally elongated laser beam output ("...kind of a wider circle, but with two sides of the circle flattened...") The pattern expands with distance and should fully cover the primary mirror center marker (donut/triangle/HotSpot, whatever). The 1mm laser aperture stop attachment provides the "...expected tiny, sharp point laser dot..."

 

That is not a holographic attachment.



#10 Tom Gwilym

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Posted 23 July 2019 - 10:28 AM

I did shine it across the room, just the same chopped circle.  Maybe I ordered or was sent the wrong thing.

 

Tom:

 

A Barlow would not be helpful.  I believe that is the later version of the Holographic attachment.  Go into a dark room and see if you can see a pattern on the wall about 4 feet away.

 

Jon



#11 Tom Gwilym

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Posted 23 July 2019 - 10:37 AM

I figured it out.  There was a drop-down on the page and Barlow was listed at the top, then there was the grid and circle below.   Yep.  Got the wrong part.  I'll contact them about a swap. 

 

SI-BARATT = Starlight Instruments Barlow Attachment. The Barlow Attachment magnifies the normally elongated laser beam output ("...kind of a wider circle, but with two sides of the circle flattened...") The pattern expands with distance and should fully cover the primary mirror center marker (donut/triangle/HotSpot, whatever). The 1mm laser aperture stop attachment provides the "...expected tiny, sharp point laser dot..."

 

That is not a holographic attachment.


Edited by Tom Gwilym, 23 July 2019 - 10:50 AM.


#12 Jon Isaacs

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Posted 23 July 2019 - 10:53 AM

Hmm...now I'm confused. I look on OPT's site and they list the "SI-HOLA" under the grid pattern Holographic attachment?  I wonder if there is some protective plastic covering it that I missed?  I may head over to the club observatory tonight to give it another try.  I'll look closer, but the "barlow" part still doesn't sound right.

Tom:

 

It's not the Barlow, the Barlow spreads out the beam.  What it looks like to me what I see without the 1mm aperture stop.  That suggests to me that the holographic element has fallen out or somehow is just not there.  

 

Since Vic Menard is now involved, I would ask him his recommendation for collimating your R-C.  

 

Jon



#13 Vic Menard

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Posted 23 July 2019 - 11:55 AM

It's not the Barlow, the Barlow spreads out the beam.  What it looks like to me what I see without the 1mm aperture stop.  That suggests to me that the holographic element has fallen out or somehow is just not there.  

 

Since Vic Menard is now involved, I would ask him his recommendation for collimating your R-C.  

The Self-Barlow Attachment does indeed spread out the beam, but at 12- to 18-inches, it looks pretty much like Tom's picture in his first post (I checked with my Glatter and Self-Barlow Attachment before I commented). And it does indeed look like what you would see without the 1mm aperture stop, only it's bigger, and not quite as sharp (I checked that too).

 

With regard to using a holographic square pattern laser to collimate a RC, it's pretty much a simple, straight forward procedure: First collimate the focuser to the secondary mirror (using either the pattern on the face of the secondary mirror or the silhouette of the secondary mirror in the pattern projected on a wall or other flat surface. Second, collimate the secondary mirror so the pattern is centered on the primary mirror (and if you have a Tublug (with the Blug removed), centered on the face of the laser). And Third, collimate the primary mirror so the pattern is centered relative to the secondary mirror and/or the pattern on the wall. That's the easy part. The harder part is getting/keeping the back focus correct, as almost any deviation (a fraction of a millimeter) will impact the image performance. Ideally, when collimating the mirrors, you want to limit the fore and aft motion by making balanced adjustments--tilt forward on one side of the mirror is balanced with tilt backward on the other side of the mirror. 


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#14 Tom Gwilym

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Posted 23 July 2019 - 12:17 PM

Thanks for the info!  I did order the wrong part I realize now - and maybe it's missing the 1mm aperture stop? 

I did email OPT about an exchange, probably my fault by messing up the drop-down on the order page.  Oops!    I'll swap this with the grid pattern, then I'll probably be back with more questions!

We are VERY close to having this thing collimated I think, we did play with the Howie Glatter with the single laser point and think we have it very close.  The correct pattern should tighten us down to a really good collimation.   This scope sure has been a bigger challenge than my own Meade LX200 for sure.

 

Here is our first good image with it, stars look pretty good and round.

66606111_2399934956787707_62170376428280

 

 

The Self-Barlow Attachment does indeed spread out the beam, but at 12- to 18-inches, it looks pretty much like Tom's picture in his first post (I checked with my Glatter and Self-Barlow Attachment before I commented). And it does indeed look like what you would see without the 1mm aperture stop, only it's bigger, and not quite as sharp (I checked that too).

 

With regard to using a holographic square pattern laser to collimate a RC, it's pretty much a simple, straight forward procedure: First collimate the focuser to the secondary mirror (using either the pattern on the face of the secondary mirror or the silhouette of the secondary mirror in the pattern projected on a wall or other flat surface. Second, collimate the secondary mirror so the pattern is centered on the primary mirror (and if you have a Tublug (with the Blug removed), centered on the face of the laser). And Third, collimate the primary mirror so the pattern is centered relative to the secondary mirror and/or the pattern on the wall. That's the easy part. The harder part is getting/keeping the back focus correct, as almost any deviation (a fraction of a millimeter) will impact the image performance. Ideally, when collimating the mirrors, you want to limit the fore and aft motion by making balanced adjustments--tilt forward on one side of the mirror is balanced with tilt backward on the other side of the mirror. 



#15 Vic Menard

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Posted 23 July 2019 - 12:35 PM

Thanks for the info!  I did order the wrong part I realize now - and maybe it's missing the 1mm aperture stop?

As far as I know, the 1mm aperture stop is included with all Glatter lasers. 



#16 Tom Gwilym

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Posted 23 July 2019 - 12:55 PM

Does that screw onto the other one to stop it down then?

 

As far as I know, the 1mm aperture stop is included with all Glatter lasers. 



#17 Vic Menard

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Posted 23 July 2019 - 01:33 PM

Does that screw onto the other one to stop it down then?

 

No. The 1mm aperture stop threads into the laser aperture just like the Self-Barlow attachment and the holographic attachments. You only use one attachment at a time, and no attachment at all when using a Blug or Tublug.


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