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

Found a 102mm unitron OTA. And finder scope, optics need cleaning

Classic Collimation Optics Mount Refractor Tripod Outreach DIY
  • Please log in to reply
19 replies to this topic

#1 chris36

chris36

    Lift Off

  • -----
  • topic starter
  • Posts: 11
  • Joined: 26 Jan 2021

Posted 16 January 2022 - 03:58 PM

I found a Unitron 102mm optical tube with finder scope. Thinking of cleaning the lens which is pretty dirty and also needs collimating. Can anyone help with the task. I can’t  find much about collimating a unitron. I would like to try. If successful my next task will be to purchase a mount for it.  Any input would help.


Edited by chris36, 16 January 2022 - 04:10 PM.

  • mdowns, Bomber Bob, MJB and 2 others like this

#2 chris36

chris36

    Lift Off

  • -----
  • topic starter
  • Posts: 11
  • Joined: 26 Jan 2021

Posted 16 January 2022 - 04:06 PM

Here are some photos 

Attached Thumbnails

  • A8EE88B8-5950-4599-B11C-14FA2611B940.jpeg
  • 92BEC1B2-3EE2-4451-8761-021EA9C918AB.jpeg
  • D4609D65-2077-468B-8E34-873862EF05B4.jpeg
  • 605F4526-63CD-47ED-B4C5-91B32CE6ADC5.jpeg

Edited by chris36, 16 January 2022 - 04:14 PM.

  • astro140, RichA, mdowns and 4 others like this

#3 John Rose

John Rose

    Mariner 2

  • *****
  • Posts: 252
  • Joined: 02 Jun 2016

Posted 16 January 2022 - 04:26 PM

Where are you located?  You might contact Astronomy_Shoppe.  Tony has worked classic scopes.



#4 RichA

RichA

    Fly Me to the Moon

  • *****
  • Posts: 5,490
  • Joined: 03 Jun 2010
  • Loc: Toronto, Canada

Posted 16 January 2022 - 04:56 PM

Here are some photos 

You can do it yourself.  You remove the lens's retaining ring.  Then you evenly lower the lens onto a narrower structure like a tin can with the top covered with a soft cloth.  You drop the lens housing below the top of the can, leaving the lens components suspended on the top of the cloth on the can.  Make an index mark with a pencil (not a pen) on the sides of the two lenses to indicate  their orientation.  Use small arrows pointed at each other.  You will notice the thicker lens compoent (the flint component) is the one of the bottom.  After you've cleaned the lens, (be careful not to disturb the little aluminum foil triangle glue to the lens surface) put it back on the top of the  can with the proper orientation, then raised the lens housing (cell) until the lens is properly seated.  You can then put the lens retainer back on.  Be CAREFUL not to allow the lens components OR the housing to tilt relative to one another or the lens may get stuck partway in the cell.  The lens cell is wider than the lens components so if during the process you feel any resistance, back off and restart.  Also, don't use acetone on the lens or methy alcohol as it may dissolve the glue holding the small aluminum spacers to the lens surface.  You can clean the lens with windex (ammonia) or isopropyl alcohol, use cotton balls in short strokes.  The process is:  Blow off dust using lens blower or lens brush, then clean it, blow/brush it one more time, reassemble.

REMOVING LENS.jpg


  • mdowns, AstroKerr, Bowlerhat and 2 others like this

#5 Defenderslideguitar

Defenderslideguitar

    Soyuz

  • *****
  • Posts: 3,982
  • Joined: 05 Oct 2016
  • Loc: Nutmeg State

Posted 16 January 2022 - 06:10 PM

Hey there     welcome aboard   you have come to the right place      

enjoy that fine classic scope     we will want to see more pics   when time allows

good luck


  • Terra Nova likes this

#6 chris36

chris36

    Lift Off

  • -----
  • topic starter
  • Posts: 11
  • Joined: 26 Jan 2021

Posted 16 January 2022 - 09:52 PM

That’s for the great advice and encouragement ! I will get back to you and let you both know how it went. Hey I play slide guitar too !

Edited by chris36, 16 January 2022 - 10:45 PM.

  • Defenderslideguitar likes this

#7 ccwemyss

ccwemyss

    Vanguard

  • *****
  • Posts: 2,166
  • Joined: 11 Aug 2016
  • Loc: Massachusetts

Posted 16 January 2022 - 10:05 PM

For collimation, you can use Cheshire collimating eyepiece. Cover the lens cell with the cap. Illuminate the diagonal part of the Cheshire with a bright light. Looking through the pinhole in the end of the Cheshire, if you see a blue reflection and a yellow reflection, it needs collimation (if the blue and yellow are centered and on top of each other, it is collimated).

 

I haven't collimated this particular Unitron cell, but it looks like there are three sets of push-pull screws on the front for adjusting it. I've only done the older Unitrons where the cell is held by screws that go through the tube, and you loosen them just enough to be able to tilt the cell. I put it face down, and push the tube around until I get alignment, then tighten them. Collimating screws make it much easier to be precise.

 

Chip W. 



#8 chris36

chris36

    Lift Off

  • -----
  • topic starter
  • Posts: 11
  • Joined: 26 Jan 2021

Posted 16 January 2022 - 10:43 PM

I have a Cheshire on the way from Agena Astro. Will try that advise thanks !

#9 chris36

chris36

    Lift Off

  • -----
  • topic starter
  • Posts: 11
  • Joined: 26 Jan 2021

Posted 16 January 2022 - 10:47 PM

Thanks rich A for the great advice !

#10 chris36

chris36

    Lift Off

  • -----
  • topic starter
  • Posts: 11
  • Joined: 26 Jan 2021

Posted 18 January 2022 - 04:25 PM

Does anyone know what each of the three sets screws do ? I have one large and two smaller screws on each side.

#11 mitsos68

mitsos68

    Messenger

  • *****
  • Posts: 421
  • Joined: 21 Jun 2012
  • Loc: Athens - Hellas.

Posted 18 January 2022 - 06:54 PM

Does anyone know what each of the three sets screws do ? I have one large and two smaller screws on each side.



Hi.
The tri member screw groups in the front retaining ring are NOT collimating screws. They ensure the proper positioning of the two objective elements in their proper mutual arrangement. Notice that normally, they are positioned above the delicate foil spacers of the lens. In the specific objective, this in not the case. So someone in the past has touched the lens. I advise you the star test the lens, before any cleaning effort. Check for  original orientation marks in the perimeter of the elements. If you can find them, use them into the reassembly process. If you cant spot markings, check carefully the inner perimeter of the lenses for any glue residue. If you cant spot any you can assume that the elements retain their original orientation, so make yours with pencil and pray for the best. The lens performance optimization with the relative rotation of the elements is a very delicate and time consuming process.

After cleaning, the front retaining ring  must return in the normal  position with the screw groups above the foil spacers. In order to adjust screw pressure, try to find description of the Newton rings method elsewhere in this forum. A very useful discussion can be found at: https://www.cloudyni...on-rings/page-2and specifically at: https://www.cloudyni...ings/?p=6285071

Regards
Dimitris


Edited by mitsos68, 19 January 2022 - 03:28 AM.

  • deSitter and Bomber Bob like this

#12 Senex Bibax

Senex Bibax

    Viking 1

  • *****
  • Posts: 993
  • Joined: 01 Feb 2019
  • Loc: Ottawa, ON

Posted 19 January 2022 - 09:16 AM

If the retaining ring  that holds the lenses in the cell is threaded in, use something softer than the glass to unscrew it if it is too deeply threaded for an optical spanner. I use a thick bamboo skewer like the kind you use for kebabs.



#13 Werckmeister

Werckmeister

    Lift Off

  • -----
  • Posts: 1
  • Joined: 08 Jun 2021
  • Loc: Netherlands

Posted 19 January 2022 - 02:02 PM

The three lobes on the outside of the lens cell are for collimating. One is just visible on the left in your first photo. Be sure to collimate the focuser first, before collimating the lenscell ;-).


  • deSitter likes this

#14 mitsos68

mitsos68

    Messenger

  • *****
  • Posts: 421
  • Joined: 21 Jun 2012
  • Loc: Athens - Hellas.

Posted 19 January 2022 - 04:07 PM

The three lobes on the outside of the lens cell are for collimating. One is just visible on the left in your first photo. Be sure to collimate the focuser first, before collimating the lenscell ;-).




Exactly!!!

#15 chris36

chris36

    Lift Off

  • -----
  • topic starter
  • Posts: 11
  • Joined: 26 Jan 2021

Posted 19 January 2022 - 10:56 PM

Thanks guys ! And thanks Dimitris, so glad for your input.

#16 mitsos68

mitsos68

    Messenger

  • *****
  • Posts: 421
  • Joined: 21 Jun 2012
  • Loc: Athens - Hellas.

Posted 20 January 2022 - 01:03 AM

Thanks guys ! And thanks Dimitris, so glad for your input.


Most welcome!

#17 chris36

chris36

    Lift Off

  • -----
  • topic starter
  • Posts: 11
  • Joined: 26 Jan 2021

Posted 20 January 2022 - 01:57 PM

Exactly!!!

Just to be clear this is the culmination screws.   

Attached Thumbnails

  • 248FFA41-C8DA-4A02-A77B-BB55CE172DA7.jpeg


#18 deSitter

deSitter

    Still in Old School

  • *****
  • Posts: 13,280
  • Joined: 09 Dec 2004

Posted 20 January 2022 - 03:02 PM

The three lobes on the outside of the lens cell are for collimating. One is just visible on the left in your first photo. Be sure to collimate the focuser first, before collimating the lenscell ;-).

Welcome to classics WM! Nice handle! Bach would approve!

 

-drl



#19 mitsos68

mitsos68

    Messenger

  • *****
  • Posts: 421
  • Joined: 21 Jun 2012
  • Loc: Athens - Hellas.

Posted 20 January 2022 - 04:05 PM

Just to be clear this is the culmination screws.


Yes!!!

#20 mitsos68

mitsos68

    Messenger

  • *****
  • Posts: 421
  • Joined: 21 Jun 2012
  • Loc: Athens - Hellas.

Posted 20 January 2022 - 04:06 PM

Just to be clear this is the culmination screws.


Yes!


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





Also tagged with one or more of these keywords: Classic, Collimation, Optics, Mount, Refractor, Tripod, Outreach, DIY



Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics