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AG Optical support group?

AG Optical FA12 12.5 inch F5 Reflectors Cleaning
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Ashraf AbuSara avatar
Ashraf AbuSara avatar
Hello fellow AG Optical owners. With the exit of AG Optical from telescope making, it feels like we are pretty much on our own. I tried contacting Dave a few times. He responded last year but lately didn't get much in the way of a response.

I really love my AGO FA12 convergent and want it to survive as long as possible, but the super humid nights and pollen is definitely taking a toll on my mirrors despite using the dew heater elements. I was hoping to see if others have information that is important to future servicing of these OTAs? 

I got in touch with Terry Ostahowski to see if they would offer recoating for the primary and secondary mirrors if needed, since they are the original makers of these mirrors. They said they would recoat them, but they would have to receive the mirrors completely disassembled. That meant removing the permanently installed correctors that are built into the primary mirror. That is not something I was willing to do since I have no idea how to put it back together and maintain the same performance. 

Terry suggested I clean the optics using these products to clean the optics:

https://www.photoniccleaning.com/default.asp

They are extremely pricy. (The cleaening kit costs more than recoating the mirror!), but I don't mind if that will allow me to maintain this OTA for a long time.

What other fellow AG Optical users are doing currently to maintain their optics?
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andrea tasselli avatar
andrea tasselli avatar
AFAIK the corrector sits inside the baffle tube. Am I wrong? Are the mirrors a type of Mangin mirror(s)? That would be surprising…
Jeffery Richards avatar
Jeffery Richards avatar
There is a YouTube video out there about a guy cleaning his iDK. That being said, if Terry recommends this product, that's good enough for me. Looks like the $241 deluxe kit would take care of my 14.5 iDK and I don't think that is overly outrageous for something to do every few years.
Ashraf AbuSara avatar
Ashraf AbuSara avatar
andrea tasselli:
AFAIK the corrector sits inside the baffle tube. Am I wrong? Are the mirrors a type of Mangin mirror(s)? That would be surprising...

The baffle tube just unscrews from the corrector housing. The corrector is permanently installed inside the middle of the mirror.  Here is what it looks like:



I have no intention of ever touching those three screws!
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Ashraf AbuSara avatar
Ashraf AbuSara avatar
Jeffery Richards:
There is a YouTube video out there about a guy cleaning his iDK. That being said, if Terry recommends this product, that's good enough for me. Looks like the $241 deluxe kit would take care of my 14.5 iDK and I don't think that is overly outrageous for something to do every few years.

Yes I agree it is actually not as bad as I thought. I was looking at the 500ml and 1000ml kits, and it seems that would be an overkill for a couple of cleanings. 

Has Dave ever supplied you with schematics / info regarding the exact mirror spacing measurements in case the secondary is removed?
Jeffery Richards avatar
Jeffery Richards avatar
Ashraf AbuSara:
Jeffery Richards:
There is a YouTube video out there about a guy cleaning his iDK. That being said, if Terry recommends this product, that's good enough for me. Looks like the $241 deluxe kit would take care of my 14.5 iDK and I don't think that is overly outrageous for something to do every few years.

Yes I agree it is actually not as bad as I thought. I was looking at the 500ml and 1000ml kits, and it seems that would be an overkill for a couple of cleanings. 

Has Dave ever supplied you with schematics / info regarding the exact mirror spacing measurements in case the secondary is removed?

No, but then I never asked. My 14.5 is from his very last run.
Ashraf AbuSara avatar
Ashraf AbuSara avatar
Jeffery Richards:
Ashraf AbuSara:
Jeffery Richards:
There is a YouTube video out there about a guy cleaning his iDK. That being said, if Terry recommends this product, that's good enough for me. Looks like the $241 deluxe kit would take care of my 14.5 iDK and I don't think that is overly outrageous for something to do every few years.

Yes I agree it is actually not as bad as I thought. I was looking at the 500ml and 1000ml kits, and it seems that would be an overkill for a couple of cleanings. 

Has Dave ever supplied you with schematics / info regarding the exact mirror spacing measurements in case the secondary is removed?

No, but then I never asked. My 14.5 is from his very last run.

Ah I see. I got my scope second hand so I never had any extensive interactions with Dave.
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Patrick avatar
Patrick avatar
I have a 12.5” idk and am also happy with it. It’s a shame Dave got out of the business, as we need more quality manufacturers in that size and type range. That was a real loss to the hobby. 
interesting what Terry told you about removing the corrector, but I understand his position. If anyone out there has ever removed and replaced a corrector (successfully) it would be good to hear from them. 
BTW, I believe Dave has committed to supporting users that bought their scopes directly from him, but not necessarily second hand owners. 
I have used the Photonic cleaning method and there are a few things to be aware of:
-you really need to apply it thickly, or when you try to pull it up it will tear and leave pieces adhered to the mirror. The instructions tell you that but don’t underestimate the thickness and quantity you will need. 
-be careful the film is really dry before removing it, or you’ll get tearing. And the adhesion supposedly reduces when the film is dry. 
-be very careful to avoid getting any of the solution on the beveled outer edge of the mirror, or against the corrector housing. Removing it from those surfaces is really difficult. The stuff goes on as a liquid and the mirror is concave…
-when I removed all of the film I was left with a ring of haze on the mirror, oddly. I don’t know why, but had to remove it with distilled water, very gently, and after removing the mirror assembly from the telescope. Granted, the mirror was pretty dirty due to dust and some condensation.
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Ashraf AbuSara avatar
Ashraf AbuSara avatar
Patrick:
I have a 12.5” idk and am also happy with it. It’s a shame Dave got out of the business, as we need more quality manufacturers in that size and type range. That was a real loss to the hobby. 
interesting what Terry told you about removing the corrector, but I understand his position. If anyone out there has ever removed and replaced a corrector (successfully) it would be good to hear from them. 
BTW, I believe Dave has committed to supporting users that bought their scopes directly from him, but not necessarily second hand owners. 
I have used the Photonic cleaning method and there are a few things to be aware of:
-you really need to apply it thickly, or when you try to pull it up it will tear and leave pieces adhered to the mirror. The instructions tell you that but don’t underestimate the thickness and quantity you will need. 
-be careful the film is really dry before removing it, or you’ll get tearing. And the adhesion supposedly reduces when the film is dry. 
-be very careful to avoid getting any of the solution on the beveled outer edge of the mirror, or against the corrector housing. Removing it from those surfaces is really difficult. The stuff goes on as a liquid and the mirror is concave…
-when I removed all of the film I was left with a ring of haze on the mirror, oddly. I don’t know why, but had to remove it with distilled water, very gently, and after removing the mirror assembly from the telescope. Granted, the mirror was pretty dirty due to dust and some condensation.

Thanks for the info Patrick. Very useful! That is very concerning regarding the "haze" you noticed after removing the application. Did you ever get in touch with First contact polymer to get some feedback on the cause? I ordered a kit so I was planning to attempt this, but definitely don't want to deal with haze afterwards.
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psparkman avatar
psparkman avatar
I have an AGO FA12, and really love it.  The original mirror had issues, so I worked with Terry Ostahowski and he actually made me a new mirror for no charge as he could not get the original mirror corrected.  So I installed and removed the mirrors several times.  It is actually straightforward to remove the primary mirror in these scopes.  I don't think that Terry is asking you to remove the corrector lenses from their housing, but he just wants the two mirrors.  The primary mirror is held against the front of the inner baffle plate by a ring with three pressure screws.  Remove this plate from the back, and the primary slides right off the central corrector assy.  You need to be very careful removing the heater bands and the temperature sensor as the wires are pretty small.  The secondary is a bit harder as you need to remove the baffle and heater bands.  Then use a razor blade to cut the silicon adhesive that is used to glue the secondary to the adjustor plate.  

It is straightforward, but you need to be careful, especially with the heater band and probe wires.  You just need to take your time, go slow, and be careful how you handle the mirrors.
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Ashraf AbuSara avatar
Ashraf AbuSara avatar
I have an AGO FA12, and really love it.  The original mirror had issues, so I worked with Terry Ostahowski and he actually made me a new mirror for no charge as he could not get the original mirror corrected.  So I installed and removed the mirrors several times.  It is actually straightforward to remove the primary mirror in these scopes.  I don't think that Terry is asking you to remove the corrector lenses from their housing, but he just wants the two mirrors.  The primary mirror is held against the front of the inner baffle plate by a ring with three pressure screws.  Remove this plate from the back, and the primary slides right off the central corrector assy.  You need to be very careful removing the heater bands and the temperature sensor as the wires are pretty small.  The secondary is a bit harder as you need to remove the baffle and heater bands.  Then use a razor blade to cut the silicon adhesive that is used to glue the secondary to the adjustor plate.  

It is straightforward, but you need to be careful, especially with the heater band and probe wires.  You just need to take your time, go slow, and be careful how you handle the mirrors.

Surprisingly Terry just told me they did not make the mirrors for the FA12. So now I am not sure who made the mirrors. I went back to AGO's website and sure enough, they don't list them as the maker for that particular model. Then I read your comment and now I am confused. 

Thank you so much for the info about the primary mirror! That is actually super helpful. Question. So when you remove the plate, and the primary slides off from central corrector assay, what steps do you take to insure that it goes back in the same orientation? I'd imagine any markings I put on the back of the mirror could disappear during the recoating process? Or is the orientation of the correctors not critical in relation to the primary and secondary mirrors?
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psparkman avatar
psparkman avatar
He definitely made the original mirror for my FA12.  Are you sure he wasn't talking about the convergent series?  Mine is an f5 scope.

I don't think that there is any reason to worry about the orientation of the mirror like on an SCT.  Since I put a new primary with the original secondary, and the performance is outstanding, I don't think there is any clocking orientation.
psparkman avatar
psparkman avatar
Sorry, the Convergent is the FA12 f5 scope.  I was thinking of the Harmer-Wynne.
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Ashraf AbuSara avatar
Ashraf AbuSara avatar
The FA12/f5 and the rest of the "Convergent" seris are Harmer-Wynne design. Dave Tandy notes that in this post here:

https://www.cloudynights.com/topic/600454-new-ag-optical-systems-f5-convergent-series-astrographs/?p=8259628

Now I am really curious to know who made those mirrors.
psparkman avatar
psparkman avatar
Mine was definitely made my Terry Ostahowski.  He still had the SN on file.
Ashraf AbuSara avatar
Ashraf AbuSara avatar
Mine was definitely made my Terry Ostahowski.  He still had the SN on file.

Very strange. Here is what they told me:

Patrick avatar
Patrick avatar
Sorry for the late reply. The haze I experienced was very faint and I don’t know what caused it. I did allow the solution plenty of time to dry, considering the ambient temperature and arid humidity. It could have been something I did wrong without being aware. In any case, the haze was easy to remove with distilled water and very light dabbing.
In fairness, the Photonic solution did do a very good job removing the vast majority of the dust which had been previously moistened onto the mirror by dew and dried. 
But a sufficiently thick application, and avoiding the corrector housing and mirror edges was really important.
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