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Low budget widest TFOV 1.25" eyepiece

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#1 petmic

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Posted 12 July 2018 - 07:41 AM

As title say I am looking for a cheap widest TFOV 1.25" eyepiece for a friend of mine. The budget is very low - 20 EUR. His scope is not worth much more lol.gif

 

I found these so far:

1. 23mm 62° Aspheric https://www.aliexpre...iceBeautifyAB=0

2. 32mm 52° Plossl https://www.aliexpre...iceBeautifyAB=0

3. 40mm 40° Plossl https://www.aliexpre...iceBeautifyAB=0

 

Which one would you pick?

 

Also, I am wondering if you can recommend something else. Thanks


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#2 Augustus

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Posted 12 July 2018 - 07:50 AM

32mm Plossl. The Aspheric isn't very good in fast scopes and doesn't have the largest possible field stop. The 40mm has a narrow AFOV.


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#3 DLuders

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Posted 12 July 2018 - 07:52 AM

Have you downloaded the "2018 Buyer's Guide to Eyepieces" spreadsheet, linked from  https://www.cloudyni...e-buyers-guide/  ?  You can convert the Suggested Retail Prices shown from US Dollars to Euros.  

 

There may be some gently-used eyepieces on a European eBay site.  Most of the eyepieces on the Cloudy Nights "Classifieds" section are being bought/sold in the USA....



#4 petmic

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Posted 12 July 2018 - 08:06 AM

Have you downloaded the "2018 Buyer's Guide to Eyepieces" spreadsheet, linked from  https://www.cloudyni...e-buyers-guide/  ?  You can convert the Suggested Retail Prices shown from US Dollars to Euros.  

 

There may be some gently-used eyepieces on a European eBay site.  Most of the eyepieces on the Cloudy Nights "Classifieds" section are being bought/sold in the USA....

I have seen that list. However, it does not contain any eyepieces with my requirement, within my limited budget and obtainable in Europe. 



#5 petmic

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Posted 12 July 2018 - 08:14 AM

32mm Plossl. The Aspheric isn't very good in fast scopes and doesn't have the largest possible field stop. The 40mm has a narrow AFOV.

It's a 70mm f/10 achromat that came with H20mm and SR4mm eyepieces. Anything is better than those. I already donated him my unused 10mm Plossl and he is after something with wider FOV.

 

I run few calculations and 40mm 40° Plossl gives exactly the same TFOV as 32mm 52°. So 40mm is out.

Aspheric EP gives about 10% less TFOV but with higher magnification - which can be an advantage. 



#6 Jon Isaacs

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Posted 12 July 2018 - 08:23 AM

Peter:

 

Anything is an upgrade from the H20.  A 25mm Plossl would be a big improvement.    At F/10, the exit pupil is already pretty small with a 32mm Plossl.. 

 

One thing too, not all 32mm Plossls provide a full 50 degree AFoV.  

 

Jon


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#7 petmic

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Posted 12 July 2018 - 08:42 AM

You are right. I have just realized some tome ago I star drifted 20,15 and 10mm Series 500 Plossls and despite being sold as 52° they were all around 44°. I think it is fair to assume a 32mm unbranded Plossl will have about the same AFOV.

Based on this review https://www.cloudyni...c/#entry6644583 I think I will probably go for the 23mm aspheric. It seems to be close to 60° AFOV so it gives the same TFOV as 44° 32mm Plossl.


Edited by petmic, 12 July 2018 - 08:43 AM.

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#8 nicknacknock

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Posted 12 July 2018 - 09:29 AM

For your focal ratio, the Vite will work very well. Lightweight, cheap and cheerful with very good performance as the f ratio gets longer :)


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#9 starcanoe

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Posted 12 July 2018 - 10:10 AM

Yes, the Vite 10mm and 23mm are pretty good...particularly at f10 ish.

 

The 4mm Vite is IMO junk. Most people seem to agree. Though some think the 4mm is passable. I guess it beats not having anything....

 

Keep in mind the Vite's do have plastic lenses...so you need to treat the optics pretty gently (most likely) if you want them to last.


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#10 sg6

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Posted 12 July 2018 - 10:55 AM

Just get a 30mm or 32mm plossl.

Aspherics are recent and at least the plossl's are well proven.



#11 csrlice12

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Posted 12 July 2018 - 01:44 PM

Are you sure the 70mm f10 uses 1.25" e yepieces?  Many used the older .965 barrel.



#12 petmic

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Posted 12 July 2018 - 02:08 PM

Are you sure the 70mm f10 uses 1.25" e yepieces?  Many used the older .965 barrel.

Yes, i am 100% sure it is 1.25". It's not a vintage scope.


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#13 tony_spina

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Posted 12 July 2018 - 03:34 PM

How about this 32mm eyepiece. Comes with a eyepiece phone holder

 

https://www.ebay.com...XoAAOSwb39bK-Qu



#14 clearwaterdave

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Posted 12 July 2018 - 08:44 PM

The 23mm vite is a fine choice.,and for the price you can get the 10mm as well.,which is better then a 10mm plossl.,imho.,
I have and use both and have no problem recomending them.,good luck.,
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#15 Jon Isaacs

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Posted 13 July 2018 - 09:31 AM

Peter:

 

The facts your friends scopes has a 1.25 inch focuser, is a 70 mm F/10 and came with a H-20 eyepiece suggests to me it might be a Celestron Powerseeker 70.

If it is a Power seeker 70, one issue is the diagonal. These have a RACI diagonal with a clear aperture of 14mm.  It's small enough that any of these longer focal length eyepieces will severely vignette, a better diagonal is also desireable.

Jon


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#16 MartinPond

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Posted 13 July 2018 - 09:54 AM

Good catch Jon!   ....I didn't see that.

 

My first was just such a PowerSeeker F/10...

 

A---Changing the diagonal to a simple $10 mirror model from Telescope Warehouse

     was a wonderous improvement, even though is was a plain 1st-surface mirror.

 

B---Lining tube and especially focuser with black wallboard sanding mesh gave a whopping

   improvement in contrast....

 

---Then, I used a few 70-deg glass aspherics (from 50s bins) ... amazing.

   ----The Vite 23mm would do that job almost as well... 

     Don't futz with eyepiece until you reduce the sheen in the focuser tube..

    Rolled emery paper will do almost as well, but sanding mesh locks itself in place

     when you push it out against the barrel/tube..

 

I would say: make sure you do steps A and B above, then toss in the Vite...

      It's a bit long to go lower power.. and bouncy to go to high power...

 

 

 

I adapted to a cleaned-up QuikSet Husky TRIPOD after that...

   The 70mm/F10 Powerseeker is wicked bouncy in the tripod...N/G over 40x....

 

Once you reline, remount the PowerSeeker and replace the EPs, it's great!


Edited by MartinPond, 13 July 2018 - 09:56 AM.


#17 25585

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Posted 15 July 2018 - 01:07 PM

Baader Eudiascopic/Orion Ultrascopic/Parks Gold/Celestron Ultima 35mm (all the same pseudo-Masuyama optics) will give the largest possible TFOV for 1.25 inch.

 

First Light Optics in the UK is selling new Baader 35s,  while stocks last.




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