Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Biconvex lenses with high focal ratio, for sale

  • Please log in to reply
106 replies to this topic

#76 Ovidiu Catalin

Ovidiu Catalin

    Mariner 2

  • -----
  • Posts: 237
  • Joined: 20 Jun 2013

Posted 02 June 2020 - 09:21 AM

Below we have the graphs made in OLSO for the three types of lenses all with a useful diameter of 36mm focal length 2000mm and the results speak for themselves, the plano convex is the best shape followed by the biconvex one which does not change much compared to the plano convex lens, the last is a positive meniscus lens.

The graph shows the meniscus lens that has the worst results, even a difference from heaven to earth, being on the last place in this ranking.

Now everything is clear, in terms of color aberration it can be corrected by extending the existing focal length and then diaphragming the lens in question to the diameter at which the image becomes clear.
If in the case of convex and biconvex flat lenses things are ok they can be used in larger diameters, now remains the meniscus lens which no matter what focal length it has always has to be diaphragmed more than the other two, so for my raw meniscus lenses both used at 25mm with focal lengths of 3.5 and 4 meters long the image is the same because the diameter does not change.

 

Plano convex:

https://1.bp.blogspo...v+simplet+1.jpg

 

Biconvex:

https://1.bp.blogspo...207550200946619

 

Meniscus:

https://1.bp.blogspo...v+simplet+3.jpg



#77 Tavi F.

Tavi F.

    Vendor (refractor optics)

  • *****
  • Vendors
  • topic starter
  • Posts: 290
  • Joined: 27 Jun 2008
  • Loc: Europe

Posted 04 July 2020 - 04:12 PM

Up!

 

Image55copy.jpg

 

Image54%252658cr.jpg


  • Ovidiu Catalin likes this

#78 Ovidiu Catalin

Ovidiu Catalin

    Mariner 2

  • -----
  • Posts: 237
  • Joined: 20 Jun 2013

Posted 09 July 2020 - 09:27 AM

luneta%2Bde%2B27mm%2Bistoric%2B-%2BCopy%

 

History of the 27/1250mm singlet refractor

https://1.bp.blogspo...opy+%282%29.jpg


Edited by Ovidiu Catalin, 10 July 2020 - 02:16 AM.


#79 Tavi F.

Tavi F.

    Vendor (refractor optics)

  • *****
  • Vendors
  • topic starter
  • Posts: 290
  • Joined: 27 Jun 2008
  • Loc: Europe

Posted 17 July 2020 - 04:49 PM

The orange Moon through my own singlet lens refractor (D38mm) with a classic orange filter at the focuser:

 

https://live.staticf...b64663156_o.jpg

 

50 images stack. The filter is made by me from an old russian glass, OC23-1 (something similar to Schott OG550). The so called Wratten #21 "orange filter" is red all day.


Edited by Tavi F., 17 July 2020 - 04:55 PM.


#80 DARKMATTER

DARKMATTER

    Explorer 1

  • -----
  • Posts: 56
  • Joined: 09 Sep 2005
  • Loc: UK.

Posted 17 July 2020 - 05:30 PM

Tavi,

Having fun with the other lenses I have purchased from you in the past.

Are you likely to make any more of the D=32mm F=1980mm lenses?

Would you consider making a D=65 or 68mm F=6500mm lens?

Thanks again

Simon


Edited by DARKMATTER, 17 July 2020 - 05:34 PM.


#81 Tavi F.

Tavi F.

    Vendor (refractor optics)

  • *****
  • Vendors
  • topic starter
  • Posts: 290
  • Joined: 27 Jun 2008
  • Loc: Europe

Posted 18 July 2020 - 03:10 AM

Thanks, Simon, for the appreciation! I still have quite a few singlets available, which are very similar to the parameters described by you. So, no plans for me of making more singlets in the near future. I was thinking in some point in time to make an even larger singlet than those of 5500mm f.l. I mean a D80mm lens with 9600mm f.l. This project would have been the next step up in my oppinion, but this remained just a thought.

 

 

As a reminder of my current offer, please see the posts #67 and #68, beginning with the following link:
https://www.cloudyni...sale/?p=9626481

 

@Ovidiu Catalin: Thanks as well, but please try to understand what I had asked you a while ago on this thread. Otherwise, people might get confused in so many content. Thanks in advance for the understanding. This is my last appeal to you.


Edited by Tavi F., 18 July 2020 - 03:17 AM.

  • Ovidiu Catalin likes this

#82 TG

TG

    Gemini

  • *****
  • Posts: 3,123
  • Joined: 02 Nov 2006
  • Loc: Latitude 47

Posted 14 August 2020 - 10:09 PM

Tavi, you are obviously skilled at making optics. Why not offer a long focus (say f/15) achromatic doublet?

#83 Tavi F.

Tavi F.

    Vendor (refractor optics)

  • *****
  • Vendors
  • topic starter
  • Posts: 290
  • Joined: 27 Jun 2008
  • Loc: Europe

Posted 14 March 2021 - 12:46 AM

Still available. More info in pm.

 

TG, I will make an achromatic Clark type objective for sale, using a dense flint. It will have an aperture of 100mm and 1200mm focal length, with basicly no coma. Hopefully, I would finish it by the end of this summer, but more info at the right time.


  • TG likes this

#84 Tavi F.

Tavi F.

    Vendor (refractor optics)

  • *****
  • Vendors
  • topic starter
  • Posts: 290
  • Joined: 27 Jun 2008
  • Loc: Europe

Posted 10 July 2021 - 12:07 AM

Hello again,

 

Still available.

 

Having 5 large lenses and 7 smaller ones, I will add a second small lens as a bonus for the first two packages. (see all the lenses: https://www.cloudyni...sale/?p=9973944 )

 

The effective price for one set (D36mm+D63mm lenses) = 50 euro (16+34). Remember, first two sets: (2xD36mm+D63mm).



#85 Tavi F.

Tavi F.

    Vendor (refractor optics)

  • *****
  • Vendors
  • topic starter
  • Posts: 290
  • Joined: 27 Jun 2008
  • Loc: Europe

Posted 12 August 2021 - 03:26 AM

Update:

 

Another package of these lenses was sold. It is going to Germany. Still available one with three lenses. And after that, I will continue to sell the standard set of two (one small + one large lenses), as the minimum pourchase.

 

Thanks.



#86 Ovidiu Catalin

Ovidiu Catalin

    Mariner 2

  • -----
  • Posts: 237
  • Joined: 20 Jun 2013

Posted 26 November 2021 - 02:56 PM

Arcturus tith the 28/1250m refractor at 150x through a skywatcher zoom eyepiece

Sunspots and a airplane at 60x with skywatcher zoom eyepiece using the 28mm refractor.

 

Attached Thumbnails

  • IMG_20210526_115040.jpg
  • IMG_20210624_190059.jpg
  • IMG_20210624_185953.jpg
  • IMG_20211126_214912.png

  • ianatcn likes this

#87 Ovidiu Catalin

Ovidiu Catalin

    Mariner 2

  • -----
  • Posts: 237
  • Joined: 20 Jun 2013

Posted 03 December 2021 - 11:31 AM

The 28/1250mm refractor 2021

 

Attached Thumbnails

  • IMG_20210912_191345 - Copy - Copy.jpg


#88 Ovidiu Catalin

Ovidiu Catalin

    Mariner 2

  • -----
  • Posts: 237
  • Joined: 20 Jun 2013

Posted 23 December 2021 - 02:26 PM

Venus through the 28/1250mm F44,6 refractor, 70x and 150x, SW zoom eyepiece, afocal, movie mode, post procesing frames.

Attached Thumbnails

  • IMG_20211222_184845_674.jpg
  • IMG_20211222_184719_989.jpg
  • IMG_20211222_191338_655.jpg

  • ianatcn likes this

#89 Ovidiu Catalin

Ovidiu Catalin

    Mariner 2

  • -----
  • Posts: 237
  • Joined: 20 Jun 2013

Posted 01 January 2022 - 01:11 PM

 The life of  Tavi's Optical The Movie

 

Chapter 1

https://www.youtube....h?v=vU9AUAJLrc8

 

Chapter 2

https://www.youtube....h?v=vtmiZc--RQc

 

Chapter 3

https://www.youtube....h?v=XJW5xGMbLac

 

Chapter 4

https://www.youtube....UjOTB9x0&t=651s

 

Chapter 5

https://www.youtube....2kgkq8LE&t=2033

 

Chapter 6

https://www.youtube....WcGuqXM&t=1203s


Edited by Ovidiu Catalin, 01 January 2022 - 01:11 PM.


#90 Ovidiu Catalin

Ovidiu Catalin

    Mariner 2

  • -----
  • Posts: 237
  • Joined: 20 Jun 2013

Posted 03 October 2022 - 10:11 AM

JUPITER and SATURN through the 28/1250mm refractor, camera ASI 034MC 12000 frames, imaging software for processing: Autostakket, Registax, Astrosurface, Lightroom

Attached Thumbnails

  • 1664791654372.jpg
  • 1664791658851.jpg
  • 1664791641491.jpg

  • LucienP likes this

#91 Ovidiu Catalin

Ovidiu Catalin

    Mariner 2

  • -----
  • Posts: 237
  • Joined: 20 Jun 2013

Posted 04 October 2022 - 02:10 PM

the Moon with the 28/1250mm refractor singlet biconvex simetric lens, camera ASI 034MC, 2000 frames, processing in Autostakket, Registax, Astrosurface, Lightroom, Photoshop.

Attached Thumbnails

  • Luna 50mm 4.jpg

Edited by Ovidiu Catalin, 04 October 2022 - 02:13 PM.


#92 Ovidiu Catalin

Ovidiu Catalin

    Mariner 2

  • -----
  • Posts: 237
  • Joined: 20 Jun 2013

Posted 04 October 2022 - 02:15 PM

2. Second photo the same settings.

Attached Thumbnails

  • Luna 50mm 5 - Copy (2).jpg


#93 Ovidiu Catalin

Ovidiu Catalin

    Mariner 2

  • -----
  • Posts: 237
  • Joined: 20 Jun 2013

Posted 09 October 2022 - 01:28 PM

Saturn through the 28/1250mm singlet refractor, 1679 frames in Firecapture, crop capture, ASI034 MC camera, processing in Autostakket, Registax and Astrosurface. A great work before clouds the take over.

 

Attached Thumbnails

  • SATURN luneta de 28.1250mm 3.jpg


#94 Ovidiu Catalin

Ovidiu Catalin

    Mariner 2

  • -----
  • Posts: 237
  • Joined: 20 Jun 2013

Posted 11 October 2022 - 05:27 AM

Saturn through the 28/1250mm refractor 1700 frames in Firecapture crop capture, ASI 034 MC camera, processing in Autostakket, Registax and Astrosurface, Lightroom.

Attached Thumbnails

  • SATURN luneta de 28.1250mm 7.jpg
  • SATURN luneta de 28.1250mm 5.jpg

Edited by Ovidiu Catalin, 11 October 2022 - 05:29 AM.


#95 Ovidiu Catalin

Ovidiu Catalin

    Mariner 2

  • -----
  • Posts: 237
  • Joined: 20 Jun 2013

Posted 12 October 2022 - 11:15 AM

Sunsports evolution today 10.10.2022  at 10:20 and 16:26 eastern time, through the 28/1250mm refractor, 1000 frames, processing in Autostakket, Registax and Astrosurface.

Attached Thumbnails

  • Soarele 28mm 3.....jpg
  • SOARELE NOU 2 ASTRO....jpg


#96 Ovidiu Catalin

Ovidiu Catalin

    Mariner 2

  • -----
  • Posts: 237
  • Joined: 20 Jun 2013

Posted 17 October 2022 - 03:21 AM

Great image of Jupiter and Saturn i taken last night using the 28/1250mm refractor, camera ASI034 for Saturn a total of 751 frames and Jupiter 15000 frames, capture in FireCapture crop image, processing in Autostakket,Registax, Astrtosurface, Lightroom.

Attached Thumbnails

  • Jupiter 28mm 1.jpg
  • Jupiter 28mm2.jpg
  • Saturn 28mm.jpg

Edited by Ovidiu Catalin, 17 October 2022 - 03:21 AM.


#97 Ovidiu Catalin

Ovidiu Catalin

    Mariner 2

  • -----
  • Posts: 237
  • Joined: 20 Jun 2013

Posted 17 October 2022 - 03:22 AM

My favorite objects to view with this particular refractor is double stars, there are amazing at the eyepiece, but when you put a camera things start to chance, its amazing what you can do with a camera at this huge focal length.

With this singlet refractor at f44,5 the airy discs are vizibile at 50x and 100x are huge at 150x much larger but round and with a circular difraction ring that is smooth, camera ASI034, frames used between 140 and 70, processing in Autostakket, Astrosurface, Lightroom.

Attached Thumbnails

  • Albireo.jpg
  • Eta Cassiopea 28mm.jpg
  • Gamma Andromedae 28mm 2.png


#98 Ovidiu Catalin

Ovidiu Catalin

    Mariner 2

  • -----
  • Posts: 237
  • Joined: 20 Jun 2013

Posted 21 October 2022 - 05:49 AM

Jupiter rotation and Io tranzit through the 28/1250mm singlet refractor, 6 images with 6000 and 13000 frames, camera ASI 034mc, inage processing in Autostakket Registax Astrosurface.

A great opotunity for the 28/1250mm singlet refractor to image this, this proves that singlet refractor's cand do real work when used with modern equipment. The 28/1250mm turns out to be a scientific instrument rather  than a archaic refractor ca cooy of 17th century refactors in modern astronomy.

These images makes me happy, the first capture has 254 frames and the next ones 6000 and 13000 frames, stakes in autostakket.

 

Attached Thumbnails

  • Jupiter Io tranzit 28mm 1.jpg
  • Jupiter Io tranzit 28mm 2.jpg
  • Jupiter Io tranzit 28mm 3.jpg
  • Jupiter Io tranzit 28mm 4.jpg
  • Jupiter Io tranzit 28mm 5.jpg
  • Jupiter Io tranzit 28mm 6.jpg

Edited by Ovidiu Catalin, 21 October 2022 - 05:51 AM.


#99 Ovidiu Catalin

Ovidiu Catalin

    Mariner 2

  • -----
  • Posts: 237
  • Joined: 20 Jun 2013

Posted 02 November 2022 - 11:18 AM

Moon + Jupiter images taken through the 28/1250mm f44.5 refractor camera ASI 034 5000 and respectively 6300 frames 25% frames percentage in Autostakket, processing in Registax Deconvolution in Astrosurface final processing Lightroom.

Attached Thumbnails

  • Luna 28mm 1 NOV 2022 (3).jpg
  • Luna 28mm 1 NOV 2022 (17).jpg
  • Luna 28mm 1 NOV 2022 (20).jpg

Edited by Ovidiu Catalin, 02 November 2022 - 11:19 AM.


#100 Tavi F.

Tavi F.

    Vendor (refractor optics)

  • *****
  • Vendors
  • topic starter
  • Posts: 290
  • Joined: 27 Jun 2008
  • Loc: Europe

Posted 03 July 2023 - 12:54 PM

Up. still available. Please see my offer, post #84: https://www.cloudyni...ale/?p=11217908




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics