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Meade Series4000 UWA 8.8mm questions

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9 replies to this topic

#1 dave brock

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Posted 24 June 2019 - 07:23 PM

I've just bought one of these 2nd hand (with rubber eye guard). I have the 5000 version already which replaced a smooth top 8.8 UWA I had for years (my favorite eyepiece) but had seen too many public nights and ended up with a scratched eye lens.
Used the 4000 last night for the first time and there are some issues. The edge of field is not sharply defined and there is some serious distortion towards the edge. The 5000 doesn't show this nor the old 4000 by memory. I assume there may be a flipped or misplaced element but cannot find a diagram on the net.
Does anyone have a diagram of the lens configuration for the series 4000 8.8? Is it the same as the smooth version?
Thanks.

#2 rowdy388

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Posted 24 June 2019 - 09:18 PM

Something is definitely not right. I have a 4000 14mm UWA (Japan) with rubber grip and eye guard.

These eyepieces were famous for their sharpness. I believe the optics are the same but many people

preferred the smooth volcano top version for the ergonomics. 



#3 dave brock

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Posted 24 June 2019 - 10:00 PM

Thanks. Certainly my smoothie was sharp to the edge with very little false colour. Preferred it to the local Society's 13mm Nagler.

#4 dave brock

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Posted 25 June 2019 - 02:04 AM

Update.

Managed to nut out the problem.

One of the lenses was in the wrong place.

All good now


Edited by dave brock, 25 June 2019 - 04:28 AM.

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#5 Ernest_SPB

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Posted 25 June 2019 - 02:18 AM

So you disassembled the eyepiece? And what was correct optical elements diagram?


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#6 dave brock

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Posted 25 June 2019 - 04:38 AM

Found a forum with a diagram of a 4.7mm UWA and a picture of the lens stack here

Translated from French.

The double convex lens (and it's spacer) next to the eye lens was sitting just to the right of the field stop.

The 8.8 seems to be the same configuration.


Edited by dave brock, 25 June 2019 - 05:08 AM.

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#7 dave brock

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Posted 25 June 2019 - 04:55 AM

There are two pics of the 8.8mm in that link. The first is showing all the components and they 

are shown stacked in the second pic. Right to left becomes top to bottom. The double convex

is hidden between two spacers in the stack (in the first groove from the top).

So it's eye lens at the top, spacer, double convex lens (hidden), spacer, lens, tall spacer, lens, then

threaded collet that includes the field stop.


Edited by dave brock, 25 June 2019 - 05:02 AM.

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#8 Tank

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Posted 25 June 2019 - 03:25 PM

good your figure it out

i was going to say that the 8.8 UWA 4000 is pretty sharp to the edge in fast scopes from my memory



#9 Castor

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Posted 27 August 2019 - 06:27 PM

Found a forum with a diagram of a 4.7mm UWA and a picture of the lens stack here

Translated from French.

The double convex lens (and it's spacer) next to the eye lens was sitting just to the right of the field stop.

The 8.8 seems to be the same configuration.

 

Hi Dave,

 

I needed my old (+16 years) and rarely used Meade Series 4000 6.7mm Ultra Wide Angle eyepiece for a project and when I took it out of its case it had mold in the lenses –inside and out.  Saddened I decided to disassemble it to clean it myself (I had no other choice except declaring it a total loss) and all was going well when the stack of lenses and spacers that I had carefully placed on the table tumbled into such a disarray that it was nearly impossible to determine what was the original order of the parts.  I tried to put it back together but when I tried the eyepiece at the scope the views were poor. confused1.gif

 

Fortunately after a search in Cloudy Nights I found your post here and with the help provided by your comments and the pictures from the French amateur astronomer that you linked I was able to put it back together in the proper order.  I just tried the eyepiece during the day with one of my small scopes viewing terrestrial objects at 90X and it all seems fine. smile.gif

 

I just wanted to say a big, THANKS! to you and the French amateur (lyl) for sharing your knowledge with us, you saved my eyepiece! flowerred.gif 


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#10 dave brock

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Posted 27 August 2019 - 06:44 PM

Glad to be of help. Main credit to lyl.đŸ˜€
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