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No DioptRX in 1.25?

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#1 denck1

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Posted 21 June 2021 - 04:48 PM

Hi Everyone, 

 

Been trying to find a Televue DioptRX in the 1.25 astigmatism correction level, and  it is out of stock everywhere and not listed on Televue's website.. all other .25 increments are listed.. It's strange. Anyone know if  they are for sale anywhere or what happened to that size by chance?

 

Thank you,

David

 



#2 J A VOLK

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Posted 21 June 2021 - 05:20 PM

I believe it is discontinued - try a 'wanted' ad for a used one.



#3 TayM57

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Posted 21 June 2021 - 05:23 PM

If your astigmatism is 1.25 diopters, you should be OK with the 1.50 dioptrx. If your astigmatism is 1.00, the 1.50 dioptrx might work. Give Don or TeleVue a call to check.



#4 SteveG

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Posted 21 June 2021 - 05:32 PM

Hi Everyone, 

 

Been trying to find a Televue DioptRX in the 1.25 astigmatism correction level, and  it is out of stock everywhere and not listed on Televue's website.. all other .25 increments are listed.. It's strange. Anyone know if  they are for sale anywhere or what happened to that size by chance?

 

Thank you,

David

I had the same dilemma - not sure if they even sold them in 1.25 CYL. I currently have (2) 1.0 and (1) 1.5 Dioptrx, and they all work great. I suggest you get the 1.5.

 

What eyepiece are you getting it for?



#5 Starman1

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Posted 21 June 2021 - 05:44 PM

TeleVue is slowly moving to 0.5 increments in diopters because if you fall in between, adding 0.25 diopter at night is usually a good thing.

The 1.75 diopter one is gone now, too.



#6 russell23

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Posted 21 June 2021 - 06:20 PM

That is an interesting decision by TeleVue.  I get it.  Stocking so many dioptRx values is probably a cost and a pain.  My understanding, and experience, suggests that the ideal nighttime astigmatism correction is 0.25 greater than the daytime correction - for larger exit pupils.  

 

So if you have a 1.0 diopter correction you would want a 1.25x.  People will have to locate that on the used market.

 

Doesn’t affect me because I didn’t get along with the dioptRx as much as my glasses, but a lot of people like them so they’ll have to adjust. 



#7 SteveG

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Posted 21 June 2021 - 09:33 PM

That is an interesting decision by TeleVue.  I get it.  Stocking so many dioptRx values is probably a cost and a pain.  My understanding, and experience, suggests that the ideal nighttime astigmatism correction is 0.25 greater than the daytime correction - for larger exit pupils.  

 

So if you have a 1.0 diopter correction you would want a 1.25x.  People will have to locate that on the used market.

 

Doesn’t affect me because I didn’t get along with the dioptRx as much as my glasses, but a lot of people like them so they’ll have to adjust. 

That's not really been my experience. I see the same amount of correction with my 1.0 as I do with my 1.5. I'm due for an exam, but I think my viewing eye will come in at 1.25 CYL.

 

I think they just dropped them because they're not needed.


Edited by SteveG, 21 June 2021 - 09:34 PM.


#8 russell23

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Posted 22 June 2021 - 06:00 AM

That's not really been my experience. I see the same amount of correction with my 1.0 as I do with my 1.5. I'm due for an exam, but I think my viewing eye will come in at 1.25 CYL.

 

I think they just dropped them because they're not needed.

It seems like that is the standard recommendation on this forum for years: add 0.25 more to your prescription to the dioptRx you select.

 

I saw this last year with my glasses.  My new optometrist backed my astigmatism correction off to 1.5 for my glasses.  This has been fine in daytime, but it made it so that the new astronomy pair of eyeglasses I bought was not enough to correct my astigmatism at exit pupils larger than 3.5mm.  When I switched to my old pair of glasses with 1.75 diopters the astigmatism was fully corrected at larger exit pupils than with the 1.5 diopter pair. 

 

It makes sense. In daytime your pupil is smaller obviously so when it opens at night I’m not surprised more astigmatism correction is needed.  It is simply the other end of the scale …where as exit pupil gets smaller, as you increase magnification, at some point you can take your glasses off and get sharp images.  As exit pupil gets larger you need more astigmatism correction.


Edited by russell23, 22 June 2021 - 06:02 AM.


#9 gwlee

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Posted 22 June 2021 - 01:19 PM

I have a 1.25 Dioptrx that I bought a few years ago, but I don’t see it on their website now.

#10 SandyHouTex

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Posted 24 June 2021 - 09:47 AM

That's not really been my experience. I see the same amount of correction with my 1.0 as I do with my 1.5. I'm due for an exam, but I think my viewing eye will come in at 1.25 CYL.

 

I think they just dropped them because they're not needed.

Actually my cylinder was 1.00, and wide field eyepieces looked horrible.  Stars were all lines.

 

The two 1.00 dioprix I have make the stars round again.


Edited by SandyHouTex, 24 June 2021 - 09:49 AM.


#11 SteveG

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Posted 24 June 2021 - 03:39 PM

Actually my cylinder was 1.00, and wide field eyepieces looked horrible.  Stars were all lines.

 

The two 1.00 dioprix I have make the stars round again.

Yea, when I got to 1.0 is when I discovered a fix was needed. The Dioptrx completely restored my pin-point stars as well!


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#12 Sol Robbins

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Posted 25 June 2021 - 09:48 AM

Yea, when I got to 1.0 is when I discovered a fix was needed. The Dioptrx completely restored my pin-point stars as well!

Same for me. There's a bit of back and forth in regard to selecting the correct Dioptrx. Some say to go the next higher diopter measurement for a Dioptrx in relation to the cylinder measured by your eye doctor. In the end, I observed with my most used low power eyepiece with my glasses on and stars were pin points. So I selected the cylinder that the eye glasses provided. Worked very well and much better than I expected. 


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#13 Starman1

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Posted 25 June 2021 - 10:31 AM

Same for me. There's a bit of back and forth in regard to selecting the correct Dioptrx. Some say to go the next higher diopter measurement for a Dioptrx in relation to the cylinder measured by your eye doctor. In the end, I observed with my most used low power eyepiece with my glasses on and stars were pin points. So I selected the cylinder that the eye glasses provided. Worked very well and much better than I expected. 

I think that depends a lot on the differential between your daylight pupil and your nighttime pupil.

For me, the difference is small--2 to 4mm, so my glasses prescription does a great job correcting at the eyepiece.

But if your pupil swings from, say, 2.5mm to 6.5mm at night, the extra astigmatism from the larger pupil may require a stronger correction at night.

I asked my optometrist about that earlier this week, and he said that it's not just the diopter of astigmatism that changes, but also the angle.

Which augurs well for the rotatable nature of the DioptRx and, perhaps, a *slightly* stronger correction.

Sol is right, though--experiment with your glasses first.


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