Date   

Re: Question About Anti-Reflection Coatings

Roland Christen
 

I believe it would have a single layer coating, not a modern multi-layer. Be careful with it.

Roland



-----Original Message-----
From: mike.hambrick@... [ap-gto]
To: ap-gto
Sent: Wed, May 15, 2019 11:03 pm
Subject: Re: [ap-gto] Question About Anti-Reflection Coatings



Thanks Roland.
From what you are describing I am looking at dew spots. Would a 1992 vintage lens count as a modern lens in terms of the coating technology ?


Best Regards

Michael Hambrick
ARLANXEO
TSR Global Manufacturing Support
PO Box 2000
Orange, TX 77631-2000
Phone: +1 (409) 882-2799
email: mike.hambrick@...




From:        "chris1011@... [ap-gto]"
To:        ap-gto@...
Date:        2019-05-15 04:15 PM
Subject:        Re: [ap-gto] Question About Anti-Reflection Coatings
Sent by:        ap-gto@...




 
Modern multilayer coatings are very tough and don't need to be babied as much as older single layer coatings. The modern ones use ion implantation which drives the coating into the molecular layer of the glass. Mirror coatings are more fragile than any of the lens coatings. Very old lenses that have been thermal cycled for many years can become fragile. Depends on how hard the initial coating was put on, at what temperature and how low the vacuum was.

The dubious looking spots are most probably dew stains that can be removed with the proper cleaning tools, but I would leave them be. They tend to have silvery reflection and are little round things.

Rolando



-----Original Message-----
From: mike.hambrick@... [ap-gto]
To: ap-gto
Sent: Wed, May 15, 2019 1:57 pm
Subject: [ap-gto] Question About Anti-Reflection Coatings



Is it possible for the anti-reflection coatings on the lenses to "flake off" ? If so, what kind of things might cause this to happen ?
One reason I am asking (besides seeing some dubious looking spots on the surface of my circa 1992 vintage 180 EDT lens) is that I saw a video posting that showed someone brushing the surface of their objective with one of the camel hair brushes that they sell for cleaning camera lenbses. I have always wondered about these brushes, and I have never used one to clean my objectives because I have always heard that the anti-reflection coatings are very fragile.
It was kind of unnerving to watch the video of the lens cleaning technique where the brush was used to dust off the lens without much caution, then the alcohol soaked wipes were used one-at-a-time with a very gentle motion.







Re: Question About Anti-Reflection Coatings

mike.hambrick@...
 

Thanks Roland.
From what you are describing I am looking at dew spots. Would a 1992 vintage lens count as a modern lens in terms of the coating technology ?


Best Regards

Michael Hambrick
ARLANXEO
TSR Global Manufacturing Support
PO Box 2000
Orange, TX 77631-2000
Phone: +1 (409) 882-2799
email: mike.hambrick@...




From:        "chris1011@... [ap-gto]" <ap-gto@...>
To:        ap-gto@...
Date:        2019-05-15 04:15 PM
Subject:        Re: [ap-gto] Question About Anti-Reflection Coatings
Sent by:        ap-gto@...




 

Modern multilayer coatings are very tough and don't need to be babied as much as older single layer coatings. The modern ones use ion implantation which drives the coating into the molecular layer of the glass. Mirror coatings are more fragile than any of the lens coatings. Very old lenses that have been thermal cycled for many years can become fragile. Depends on how hard the initial coating was put on, at what temperature and how low the vacuum was.


The dubious looking spots are most probably dew stains that can be removed with the proper cleaning tools, but I would leave them be. They tend to have silvery reflection and are little round things.

Rolando



-----Original Message-----
From: mike.hambrick@... [ap-gto] <ap-gto@...>
To: ap-gto <ap-gto@...>
Sent: Wed, May 15, 2019 1:57 pm
Subject: [ap-gto] Question About Anti-Reflection Coatings



Is it possible for the anti-reflection coatings on the lenses to "flake off" ? If so, what kind of things might cause this to happen ?
One reason I am asking (besides seeing some dubious looking spots on the surface of my circa 1992 vintage 180 EDT lens) is that I saw a video posting that showed someone brushing the surface of their objective with one of the camel hair brushes that they sell for cleaning camera lenbses. I have always wondered about these brushes, and I have never used one to clean my objectives because I have always heard that the anti-reflection coatings are very fragile.
It was kind of unnerving to watch the video of the lens cleaning technique where the brush was used to dust off the lens without much caution, then the alcohol soaked wipes were used one-at-a-time with a very gentle motion.





Re: APCC feature request

Paul
 

Indeed. I should have stressed in my original suggestion for the new feature that my presumption is that this is an issue with my OTA and not my mount.

I just want to be able to put an OTA on it and give APCC a figure for that OTA's rough cone error (value in arcminutes towards/away from saddle front).


Re: Question About Anti-Reflection Coatings

Roland Christen
 

Modern multilayer coatings are very tough and don't need to be babied as much as older single layer coatings. The modern ones use ion implantation which drives the coating into the molecular layer of the glass. Mirror coatings are more fragile than any of the lens coatings. Very old lenses that have been thermal cycled for many years can become fragile. Depends on how hard the initial coating was put on, at what temperature and how low the vacuum was.

The dubious looking spots are most probably dew stains that can be removed with the proper cleaning tools, but I would leave them be. They tend to have silvery reflection and are little round things.

Rolando



-----Original Message-----
From: mike.hambrick@... [ap-gto]
To: ap-gto
Sent: Wed, May 15, 2019 1:57 pm
Subject: [ap-gto] Question About Anti-Reflection Coatings



Is it possible for the anti-reflection coatings on the lenses to "flake off" ? If so, what kind of things might cause this to happen ?
One reason I am asking (besides seeing some dubious looking spots on the surface of my circa 1992 vintage 180 EDT lens) is that I saw a video posting that showed someone brushing the surface of their objective with one of the camel hair brushes that they sell for cleaning camera lenbses. I have always wondered about these brushes, and I have never used one to clean my objectives because I have always heard that the anti-reflection coatings are very fragile.
It was kind of unnerving to watch the video of the lens cleaning technique where the brush was used to dust off the lens without much caution, then the alcohol soaked wipes were used one-at-a-time with a very gentle motion.




Question About Anti-Reflection Coatings

mike.hambrick@...
 

Is it possible for the anti-reflection coatings on the lenses to "flake off" ? If so, what kind of things might cause this to happen ?

One reason I am asking (besides seeing some dubious looking spots on the surface of my circa 1992 vintage 180 EDT lens) is that I saw a video posting that showed someone brushing the surface of their objective with one of the camel hair brushes that they sell for cleaning camera lenbses. I have always wondered about these brushes, and I have never used one to clean my objectives because I have always heard that the anti-reflection coatings are very fragile.

It was kind of unnerving to watch the video of the lens cleaning technique where the brush was used to dust off the lens without much caution, then the alcohol soaked wipes were used one-at-a-time with a very gentle motion.



Re: newbie question on balancing mount

Mike Dodd
 

On 5/15/2019 10:02 AM, zicherja@yahoo.com [ap-gto] wrote:
It became difficult to slide the scope
forward with one hand (as it was not flush in the saddle at this point)
while using the other hand to control the mount from crashing down.
There's no question that balancing a mount alone is tricky and nerve-wracking -- especially if the mount is on a tripod.

I sometimes balance my AP1200 and 130mm APO by myself, but the AP1200 is installed on a concrete pier. Even so, my wife often comes along to hold the OTA while I slide the dovetail plate.

I have one suggestion that might make it easier to slide the dovetail plate:Apply a thin coating of oil or silicone lubricant. I've found that the anodized surfaces sometimes tend to "grab" when trying to slide them.

I put a few drops of oil or a couple shots of spray silicone on a paper towel, mush it around a bit, then slide the paper towel along the dovetail rail's flanges.

Hope this helps (a bit).

--
Mike

Mike Dodd
Louisa County, Virginia USA
http://astronomy.mdodd.com


Re: New file uploaded to ap-gto

Roland Christen
 


I normally set Min Move between 0.6" and 0.8" since my seeing conditions are usually less than ideal.
On a poorer night I set the MinMove to 0.2 pixel, which is about 0.6 arc sec.

Rolando


-----Original Message-----
From: pnagy@... [ap-gto]
To: ap-gto
Sent: Wed, May 15, 2019 12:42 pm
Subject: Re: [ap-gto] New file uploaded to ap-gto

"Yes, I meant pixels. If you go to the images I posted, all the settings are there for your perusal.

Rolando"

Yes, I see you were using 130GTX so the Min Move was either 0.21" native or 0.29" with Quad TCC if I caluclated correctly. That's pretty tight. I normally set Min Move between 0.6" and 0.8" since my seeing conditions are usually less than ideal.

Thanks,

Peter
Peter

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Re: New file uploaded to ap-gto

topboxman
 

"Yes, I meant pixels. If you go to the images I posted, all the settings are there for your perusal.

Rolando"

Yes, I see you were using 130GTX so the Min Move was either 0.21" native or 0.29" with Quad TCC if I caluclated correctly. That's pretty tight. I normally set Min Move between 0.6" and 0.8" since my seeing conditions are usually less than ideal.

Thanks,
Peter
Peter


Re: New file uploaded to ap-gto

Roland Christen
 


"Do you mean 0.1 pixel? If so, what is it in arcseconds with the equipment you were using?
Yes, I meant pixels. If you go to the images I posted, all the settings are there for your perusal.

Rolando


-----Original Message-----
From: pnagy@... [ap-gto]
To: ap-gto
Sent: Wed, May 15, 2019 12:19 pm
Subject: Re: [ap-gto] New file uploaded to ap-gto

"Both RA and Dec set to 70%, both Min Moves were set to 0.1 seconds.

Rolando"

"Do you mean 0.1 pixel? If so, what is it in arcseconds with the equipment you were using?

I prefer PHD2 use arcseconds instead of pixels."


Peter

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Re: newbie question on balancing mount

Roland Christen
 


Balance with the scope horizontal.  This would be Park 1 or 4 (LINK).  You still need to keep control of the OTA, but it's easier when the OTA is level. 
I want to caution everyone about trying to balance when the mount is in Park1 or 4.

NEVER back the worm off in either of those mount positions, and also never try to put the worm back into mesh there. ALWAYS back the worm off and reset the worm in Park3. When you try to back the worm off in Park1 or 4, you can easily lose control of a heavy tube and can damage the worm as it comes into or out of mesh. This does not occur in Park3, which is the only stable position for both axes.

You must always start with the mount in Park3 before backing off the worm. Then you can swing the scope to the position where you can feel the balance. Then swing it back to Park3 position, lock the worms before trying to change the balance points or move the tube/dovetail.

Rolando


-----Original Message-----
From: bryancashion@... [ap-gto] To: ap-gto
Sent: Wed, May 15, 2019 8:47 am
Subject: [ap-gto] Re: newbie question on balancing mount



Jason

A few suggestions

1.  Balance with the scope horizontal.  This would be Park 1 or 4 (LINK).  You still need to keep control of the OTA, but it's easier when the OTA is level. 
2.  Balance Dec first (Slide scope in saddle).  Balance RA second (Slide counterweights)
3.  See AP recommendations on balancing (LINK)


Bryan



Re: New file uploaded to ap-gto

topboxman
 

"Both RA and Dec set to 70%, both Min Moves were set to 0.1 seconds.

Rolando"

"Do you mean 0.1 pixel? If so, what is it in arcseconds with the equipment you were using?

I prefer PHD2 use arcseconds instead of pixels."

Peter


Re: newbie question on balancing mount

Jason Zicherman
 

thanks rolando. this sounds like a much smarter way then what I did. 

I believe I was in the park 5 position with an unbalanced scope in the dec axis when I  disengaged worms and loosened the the saddle screws.


I won't do that again.

jason



Re: APCC feature request

W Hilmo
 

Astro-Physics mounts don’t have orthogonality errors J

 

Any cone error is coming from the OTA.  My C14, in particular, has some cone error.  I could fix it by using a shim between the dovetail and the scope itself, but the Celestron dovetail is not easy to work with.  I’ve considered switching to a Losmandy dovetail, or even rings, but then the OTA would not fit into my JMI case.

 

From: ap-gto@... [mailto:ap-gto@...]
Sent: Wednesday, May 15, 2019 8:24 AM
To: ap-gto@...
Subject: Re: [ap-gto] APCC feature request

 

 

Hi Wade,

 

    I don’t understand your concern, about needing a different saddle adjustment for every scope.

You are shimming the saddle “for the mount” orthogonality error, not for each of the scopes. Once you have the saddle orthogonally corrected, ALL other scopes will then be automatically now aligned to the new correct offset position.

 

Joe


Re: APCC feature request

Roland Christen
 


You are shimming the saddle “for the mount” orthogonality error
Generally the mount won't have an orthogonal problem. The orthogonal problem usually occurs in the telescope tube assembly when the optical and mechanical axes don't coincide. This normally occurs in Cassegrains, and in the tube rings of refractors.

Rolando


-----Original Message-----
From: 'Joseph Zeglinski' J.Zeglinski@... [ap-gto]
To: ap-gto
Sent: Wed, May 15, 2019 10:31 am
Subject: Re: [ap-gto] APCC feature request



Hi Wade,
 
    I don’t understand your concern, about needing a different saddle adjustment for every scope.
You are shimming the saddle “for the mount” orthogonality error, not for each of the scopes. Once you have the saddle orthogonally corrected, ALL other scopes will then be automatically now aligned to the new correct offset position.
 
Joe



Re: newbie question on balancing mount

Roland Christen
 


When counterbalancing the Declination axis, with the worms disengaged, I am finding it very dangerous unscrewing the saddle knobs with one hand while supporting the scope with the other
Hello,

Yes, balancing with the worms disengaged is dangerous. here's what I do:

Before placing the scope on the mount, put the scope (plus any accessories in the focuser) into the rings and dovetail on a bench or table top. Place a round dowel pin or round pencil at 90 degrees underneath the dovetail plate and roll the entire assembly back and forth to find the exact balance point. Mark that balance point on the dovetail and on the scope with a piece of tape.

Place the dovetail and rings onto the mount, open the rings and place the scope into the rings, lining up the tape marks. Now you are ready for final balance.

1) With worms engaged, loosen the clutches first and check to see if you are roughly in balance.
2) place the scope in Park3 position by moving the scope manually with clutches loose.
3) tighten one or two clutch knobs and disengage the Dec worms while holding onto the scope
4) slowly swing the scope around to feel the balance.
5) swing the scope back to Park3 and re-engage the worms

Now you can move the scope to horizontal (Park2), loosen the scope rings and slide the scope back and forth for final fine balance. Moving a heavy scope by sliding the dovetail is a 2 man job and I would not recommend it. Also, not recommended to move the scope in the rings when the worms are disengaged.

Rolando


-----Original Message-----
From: zicherja@... [ap-gto]
To: ap-gto
Sent: Wed, May 15, 2019 7:49 am
Subject: [ap-gto] newbie question on balancing mount



This is a very basic question. I just received my TEC 140 scope and am mounting it on the AP 1100. I am new to refraactors and GE mounts.  

Just started withe the basics setting up the scope and mount in my basement. 

When counterbalancing the Declination axis, with the worms disengaged, I am finding it very dangerous unscrewing the saddle knobs with one hand while supporting the scope with the other (while the scope is on the incline plane at 40 degrees). I basically placed my chest behind the scope to serve as a frame to protect against the scope sliding down the mount.   It seems like a distaster waiting to happen with heavy scopes and tall mounts.  


I can't really find any good youtube videos showing people actually sliding large heavy scopes/dovetails  in their saddle plate when counterbalancing so that I can  learn proper technique. Clearly this is not an issue with small light scopes on small mounts/tripods/piers.

So is this intended to be a two person job?  Is there some safety mechanism that would prevent a catastrophe where the scope slides off as the saddle in an uncontrolled fashion when the saddle is loosened?  or is there a technique I am missing?

If there are any video links people know of, that would be great.

thanks.

Jason



Re: APCC feature request

Joe Zeglinski
 

Hi Wade,
 
    I don’t understand your concern, about needing a different saddle adjustment for every scope.
You are shimming the saddle “for the mount” orthogonality error, not for each of the scopes. Once you have the saddle orthogonally corrected, ALL other scopes will then be automatically now aligned to the new correct offset position.
 
Joe


Re: newbie question on balancing mount

Jason Zicherman
 

I like that idea. 


Re: newbie question on balancing mount

Jason Zicherman
 

this is exactly what I tried last night and when I loosed the screws on the saddle, the counter weight on the other side started tilting the mount and scope upwards such that the scope in the dovetail was slightly tilted in the saddle plate.  It  became difficult to slide the scope forward with one hand (as it was not flush in the saddle at this point) while using the other hand to control the mount from crashing down. 

 I screamed for my wife to come down as I was sure there was an impending disaster waiting to happen and she controlled  weight as I took the scope off the saddle plate.

not sure what I am doing wrong.

Jason


Re: newbie question on balancing mount

Worsel
 

Jason

Park 5 will also work if you have APCC.

Bryan


Re: newbie question on balancing mount

Worsel
 

Jason

A few suggestions

1.  Balance with the scope horizontal.  This would be Park 1 or 4 (LINK).  You still need to keep control of the OTA, but it's easier when the OTA is level. 
2.  Balance Dec first (Slide scope in saddle).  Balance RA second (Slide counterweights)
3.  See AP recommendations on balancing (LINK)


Bryan

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