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Biconvex lenses with high focal ratio, for sale

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66 replies to this topic

#26 Ovidiu Catalin

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Posted 16 August 2016 - 06:14 AM

Nice images Tavi, your lenes are very good.


Edited by Ovidiu Catalin, 16 August 2016 - 06:15 AM.


#27 Ovidiu Catalin

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Posted 16 August 2016 - 06:34 AM

This is my objective made by Tavi F nr6 good lens, i use it for Solar projection at prime focus, the diameter is 40mm / 2400.

Very good also for prime focus projection the lens does a very nice job.

The objective lens cell its mouned o a eq1 mount and rise up, using a white paper the image of the sun its delivered by the lens.

I try to make a long focus 17th century telescope out of this lens but i have faild.

Here in Romania are to poor resources, ideal will be a aluminium long tube.

But this is not a big truble, it works good has it is. :cool:

 

Attached Thumbnails

  • IMG_20160720_194850.jpg
  • IMG_20160720_194309-1.jpg


#28 Tavi F.

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Posted 07 November 2016 - 02:46 PM

Up.

 

Thanks, Ovidiu.



#29 Tavi F.

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Posted 18 February 2017 - 09:33 AM

Up!

 



#30 Tavi F.

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Posted 22 February 2017 - 01:15 PM

By the way, you can find the description of the remaining lens in post #24. More quickly accessible at the link: http://www.cloudynig...sale/?p=7334401

 

P.S. For contact and ordering, please send me a p.m.


Edited by Tavi F., 23 February 2017 - 12:57 PM.


#31 Tavi F.

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Posted 24 February 2017 - 05:50 AM

And here is the lens in discussion:

 

14n09hl.jpg

 

vfzjgz.jpg



#32 Ovidiu Catalin

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Posted 24 July 2017 - 06:04 AM

New lenes from Ovi's Optical for solar projection, aperture 30mm to 20mm stops and with very long FL up to 5m
Lens type meniscus
Extreme durability
Not For sale
Lens 1

Aperture 20mm fl 1300,
Lens 2 Aperture 25mm fl 2m
Lens 3 Aperture 28mm fl 4m
Lens 4 Aperture 30mm fl 5m


Edited by Ovidiu Catalin, 24 July 2017 - 06:13 AM.


#33 Ovidiu Catalin

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Posted 24 July 2017 - 09:52 AM

Optical meniscus singlet lenses at Ovi's Optical are used for non eyepiece solar projections, the same with a 40mm f50 Tavi's Optical objective.

I do not have Objectives lenes form Tavi's Optical i just sold the last pice, i have'd a set of 3 objectives.

Its not a big diffrence betwen simetrical lens and meniscus when it comes to solar projection only the aperture is reduced a little bit.

I also sold my 28mm simetrical to, because i do not realy like those lenses and i am not building 17th century structure scopes anymore, so i did not find any use for those objective lenses, it make the sun to bright and also if the aperture is reduces it will be the same with my meniscus lenses.

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  • 20248178_785882921592210_8104558363481869399_o_187.jpg
  • 20248505_785904888256680_5730976940666728291_o_110.jpg
  • 20280394_785904541590048_7486054360062099339_o_120.jpg
  • 20280621_785882744925561_7661723902746786361_o_880.jpg

Edited by Ovidiu Catalin, 24 July 2017 - 10:04 AM.


#34 Ovidiu Catalin

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Posted 26 July 2017 - 01:59 AM

Ovi's Optical objectives for Solar projection

Attached Thumbnails

  • IMG_20170723_100256.jpg

Edited by Ovidiu Catalin, 26 July 2017 - 02:27 AM.


#35 Ovidiu Catalin

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Posted 26 July 2017 - 03:44 AM

New Tavi'Optical objective in action for Solar projection with eyepiece this time in a aerial telescope sistem.

Lens specification:

 Duseful = 28mm;

focal length in G-channel: F = 1250mm;
- total diameter: Dt = ~35mm;
- center thickness: tc = ~6.5mm;
- high precision optical diameter: Duseful = 28mm;
- relative opening ("focal ratio"): N = F/Duseful = 44.64;
- the chromatic aberration coefficient: x = N/Duseful = 1.59

 

The objective lens cell is mounted on a pole or a normal tripod and the light will focus on a paper, with a eyepiece at the focal point provides the image. You can use a rope to center the optics.

Attached Thumbnails

  • IMG_20170726_093935.jpg
  • IMG_20170726_093925.jpg

Edited by Ovidiu Catalin, 26 July 2017 - 07:49 AM.


#36 Ovidiu Catalin

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Posted 02 September 2017 - 08:03 AM

Tavi's Optical simetric lens 28/1250mm Solar projection on white paper toady in the view comes the new group AR12674 and AR12673.

Tavi's Optical 28mm objectis is the best in the world.

Attached Thumbnails

  • IMG_20170902_104807.jpg
  • IMG_20170902_101433.jpg
  • Obiectiv 28mm simplet.jpg


#37 Ovidiu Catalin

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Posted 02 September 2017 - 08:16 AM

The objective can work very well on solar projection without eyepiece this is what Tavi and i have made its a greate way to have a non eyepiece sistem very good for solar viewing.

The lens is very good and has a fine surface and good optical polishing.

Attached Thumbnails

  • Objective lens.jpg
  • Opticals 28mm Solar lens.jpg


#38 Ovidiu Catalin

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Posted 10 September 2017 - 10:09 AM

The sun today with Tavi's Optical 28/1250mm lens

Attached Thumbnails

  • Soarele prime focus.JPG

Edited by Ovidiu Catalin, 10 September 2017 - 10:12 AM.


#39 sarastro

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Posted 29 January 2018 - 06:25 PM

And here is the lens in discussion:

 

14n09hl.jpg

 

vfzjgz.jpg

Hi Tavi,

 

Is this lens still available?



#40 Tavi F.

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Posted 30 January 2018 - 11:44 AM

Hi,

Yes, I just sent you the answer in pm. Thanks.


Edited by Tavi F., 30 January 2018 - 11:44 AM.


#41 Tavi F.

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Posted 05 February 2018 - 06:45 AM

The last lens available was sold. Thanks.



#42 Tavi F.

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Posted 09 May 2018 - 02:24 AM

And the singlets story is not over, after all. I will make another two types of objectives, presentable as a set, but more info at the right time... probable in the autumn or winter this year.

 

Thanks.



#43 sarastro

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Posted 26 October 2018 - 01:48 AM

Tavi

How are those lenses coming along?



#44 Tavi F.

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Posted 04 November 2018 - 01:28 PM

Update: New series of singlet lens objectives are in the making!

 

4hdw6u.jpg

 

m9nkom.jpg


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#45 Astrojensen

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Posted 12 November 2018 - 05:20 AM

How large are they and what focal lengths? Prices? 

 

 

Clear skies!
Thomas, Denmark



#46 Tavi F.

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Posted 12 November 2018 - 05:49 PM

There are two main types: 1) D36mm, F1800mm and 2) D63mm, F5500mm.  And I will sell them as a set of two, but more details and pricing after theirs finalization.


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#47 Tavi F.

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Posted 26 March 2019 - 02:52 PM

Hello,

 

Due to some personal problems, the process o finishing these lenses was somewhat delayed. Sorry for that.

 

By this time I have all the small lenses complete and a few of the large ones finished, to complete the sets. One of the small lenses (D36mm) available is from BK7 glass (at the same price, available to anyone who wants it first). Apart from these a have one lens of a 3rd type, which is a D38mm, F2030mm (made also in this period). It is a BK7 lens. The rest of the smaller lens are from good plate glass (without  any striae), the one specimen from my original 8mm thick plate, thicken down to 6mm. 

 

The lowest selling prices are:

1. set of D36mm+D63mm lenses = 50 euro (16+34)
2. set of D38mm+D63mm lenses = 54 euro (20+34)

For purchasing more than 2 lenses, the price is the sum of individual prices written in the brackets.
All the lenses are individually worked and hand made.
More to come. Thanks!

 

2nsxmoz.jpg



#48 Tavi F.

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Posted 28 March 2019 - 04:33 AM

Update: Two sets of lenses (D36+D63) were sold. It will be sent to Australia. Thanks.

 

The D38mm lens is virtualy wanted by two persons. The first one to make a clear commitment to it, it will be his.



#49 DARKMATTER

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Posted 28 March 2019 - 04:49 AM

Payment sent for the 36mm BK7 lens a 38mm BK7 lens and the 63mm lens

Thanks

Simon



#50 Tavi F.

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Posted 28 March 2019 - 12:19 PM

Update 2: Another 3 lenses were sold. The D36mm(BK7), D38mm and one of the largest type.

Thanks again, Simon.


Edited by Tavi F., 28 March 2019 - 12:19 PM.

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