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Trouble focusing 5mm in TV-85

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#1 MarkGregory

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Posted 03 April 2020 - 08:01 PM

It was good seeing tonight so I thought I would try a new TeleVue ocular I just purchased, a 5mm Delite. I couldn’t get the Moon in focus. Just saw a kind of glowing out of focus blob in the eyepiece. Racked the focuser in and out to no avail. No problem with my 24mm Panoptic or 17.3 Delos. But couldn’t get the 5 to focus no matter what. Can you tell me what I did wrong? Any suggestions? Thanks, Mark



#2 msl615

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Posted 03 April 2020 - 08:12 PM

That is very strange. Of those, the Delos 17.3 is the odd duck, and requires more infocus, but the Pan 24 and the 5 Delite are in the same focus group (B) which means they should almost be parfocal.

 

Some ideas: 

 

I assume you have looked straight through the 5mm just holding it by itself up to your eyes....does it seem different than how the Delos or Pan look when removed from the scope? 

 

If you shake it, does anything rattle around, as if an internal lens has come loose? 

 

Same focus problem when you tried it mounted your three other scopes?

 

Keep us informed as the  mystery unfolds!

 

Mike


Edited by msl615, 03 April 2020 - 08:13 PM.

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#3 Migwan

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Posted 03 April 2020 - 08:21 PM

Probably silly of me to mention, but make sure the EP is sitting snug all the way in the diagonal.   Tried a Morpheus in my ST80 yesterday to look at the moon and there was a bit of a hitch.  I couldn't get the EP all the way in and there wasn't enough in focus that way.

 

jd


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#4 25585

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Posted 04 April 2020 - 12:59 AM

It was good seeing tonight so I thought I would try a new TeleVue ocular I just purchased, a 5mm Delite. I couldn’t get the Moon in focus. Just saw a kind of glowing out of focus blob in the eyepiece. Racked the focuser in and out to no avail. No problem with my 24mm Panoptic or 17.3 Delos. But couldn’t get the 5 to focus no matter what. Can you tell me what I did wrong? Any suggestions? Thanks, Mark

What size diagonal are you using? 



#5 MarkGregory

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Posted 04 April 2020 - 04:46 AM

That is very strange. Of those, the Delos 17.3 is the odd duck, and requires more infocus, but the Pan 24 and the 5 Delite are in the same focus group (B) which means they should almost be parfocal.

 

Some ideas: 

 

I assume you have looked straight through the 5mm just holding it by itself up to your eyes....does it seem different than how the Delos or Pan look when removed from the scope? 

 

If you shake it, does anything rattle around, as if an internal lens has come loose? 

 

Same focus problem when you tried it mounted your three other scopes?

 

Keep us informed as the  mystery unfolds!

 

Mike

Was tired last night so I gave up. Will tackle the issue today and see if I can figure it out. Thanks for your advice. 



#6 MarkGregory

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Posted 04 April 2020 - 04:46 AM

What size diagonal are you using? 

2 inch



#7 Starman1

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Posted 04 April 2020 - 11:53 AM

It should be parfocal with the 24mm Panoptic, so it makes me wonder if the eyepiece is new or used.

If used, perhaps the previous owner took it apart and reassembled it wrong.

If new, I have no clue.  It does have a long eye relief, so if you view without glasses, raise the eyecup a few lines and try again.

The eyecup functions the same as on the Delos.

 

Also, try in the daylight on a distant target.  Focus the 24mm and drop in the 5mm.  It should be close to focus.

The magnification might be too high for a sharp image in the daytime, but it should at least be close to as good a focus as you can achieve.

Daytime air is rarely steady enough to use magnifications above 60x, so 120x isn't likely to give you a sharp image.


Edited by Starman1, 04 April 2020 - 11:54 AM.

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#8 MarkGregory

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Posted 04 April 2020 - 12:31 PM

Problem solved. User error. Turns out it was my impatience last night and failure to take my time to assess the situation. Today, I took ALL of my eyepieces outside and gave them a test including the 5mm. All focused well. I think I over focused last night with the 5mm and simply failed to spend the time necessary to determine the problem. All of you gave me great tips and I thank you. It is so helpful to have friends on-line who care enough to give solid help. Clear skies. Out for the Moon tonight. Mark


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#9 msl615

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Posted 04 April 2020 - 12:58 PM

Glad it worked out for you.... One of my favorite "head slap" events like this for me was putting the eyepiece in with the translucent end cap still on the barrel....it did not work very well! You might ask how a 1.25 inch barrel could even be fitted into the holder with the end cap on?  I was using a 2 inch focuser and had a 1.25 to 2 inch adapter on the eyepiece.  I switched out the 1.25 ep for a 2 inch and took the entire assembly (1.25 ep and its adapter) out as a unit. Slipped on the end cap to protect it and voila!  Easy enough now to put the entire assembly back into the 2 inch diagonal with the end cap still on.   Took me a bit to figure that one out in the dark and cold. 

 

Mike


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#10 jmillsbss

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Posted 04 April 2020 - 02:18 PM

Glad it worked out for you.... One of my favorite "head slap" events like this for me was putting the eyepiece in with the translucent end cap still on the barrel....it did not work very well! You might ask how a 1.25 inch barrel could even be fitted into the holder with the end cap on?  I was using a 2 inch focuser and had a 1.25 to 2 inch adapter on the eyepiece.  I switched out the 1.25 ep for a 2 inch and took the entire assembly (1.25 ep and its adapter) out as a unit. Slipped on the end cap to protect it and voila!  Easy enough now to put the entire assembly back into the 2 inch diagonal with the end cap still on.   Took me a bit to figure that one out in the dark and cold. 

 

Mike

These are the sorts of things that happen when old eyes and darkness collide!  I started putting reflective tape on all my caps so if they get away from me, I can hit the ground with a red flashlight and find them quickly.  Otherwise, well, y'all understand....


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#11 SeattleScott

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Posted 04 April 2020 - 02:45 PM

Glad it worked out for you.... One of my favorite "head slap" events like this for me was putting the eyepiece in with the translucent end cap still on the barrel....it did not work very well! You might ask how a 1.25 inch barrel could even be fitted into the holder with the end cap on? I was using a 2 inch focuser and had a 1.25 to 2 inch adapter on the eyepiece. I switched out the 1.25 ep for a 2 inch and took the entire assembly (1.25 ep and its adapter) out as a unit. Slipped on the end cap to protect it and voila! Easy enough now to put the entire assembly back into the 2 inch diagonal with the end cap still on. Took me a bit to figure that one out in the dark and cold.

Mike

I had the same thing happen a few nights ago! I was about to order a new Morpheus. At least with black caps it is pretty obvious what’s wrong.

Scott
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#12 MarkGregory

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Posted 04 April 2020 - 03:07 PM

Glad it worked out for you.... One of my favorite "head slap" events like this for me was putting the eyepiece in with the translucent end cap still on the barrel....it did not work very well! You might ask how a 1.25 inch barrel could even be fitted into the holder with the end cap on?  I was using a 2 inch focuser and had a 1.25 to 2 inch adapter on the eyepiece.  I switched out the 1.25 ep for a 2 inch and took the entire assembly (1.25 ep and its adapter) out as a unit. Slipped on the end cap to protect it and voila!  Easy enough now to put the entire assembly back into the 2 inch diagonal with the end cap still on.   Took me a bit to figure that one out in the dark and cold. 

 

Mike

Thanks for sharing your story. It made me laugh out loud. I love when that happens because it doesn’t happen often enough. Hope you and all of your neighbors are safe from the Corona Virus. Mark



#13 GeneT

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Posted 04 April 2020 - 04:36 PM

Glad it worked out for you.... One of my favorite "head slap" events like this for me was putting the eyepiece in with the translucent end cap still on the barrel....it did not work very well! Mike

I did that once.


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#14 Jon Isaacs

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Posted 05 April 2020 - 04:30 AM

I did that once.

 

Only once?  

 

Jon


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