Return to the Cloudy Nights Telescope Reviews home pageAstronomics discounts for Cloudy Nights members
· Get a Cloudy Nights T-Shirt · Submit a Review / Article

Click here if you are having trouble logging into the forums

Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu… uh, User

Equipment Discussions >> Eyepieces

Pages: 1 | 2 | (show all)
precaud
scholastic sledgehammer
*****

Reged: 12/05/12

Loc: north central New Mexico
A how-to for eyepiece disassembly/cleaning? new
      #6320030 - 01/18/14 09:08 AM

and re-assembly...

Does one exist?


Post Extras: Print Post   Remind Me!   Notify Moderator  
BillP
Postmaster
*****

Reged: 11/26/06

Loc: Vienna, VA
Re: A how-to for eyepiece disassembly/cleaning? new [Re: precaud]
      #6320039 - 01/18/14 09:14 AM

I've never come across any. I would not think that there could be just one manual as each vendor has totally different ways of doing adjustable eye guards and such, so gets kind of unique. Even for the simple classic designs like Plossls and Orthos I've come across multiple methods. e.g., Brandons come apart totally differently from TV Plossls as example.

Post Extras: Print Post   Remind Me!   Notify Moderator  
precaud
scholastic sledgehammer
*****

Reged: 12/05/12

Loc: north central New Mexico
Re: A how-to for eyepiece disassembly/cleaning? new [Re: BillP]
      #6320068 - 01/18/14 09:37 AM

Hmmm... well that's unfortunate. What I had in mind was not step-by-step, but overview/procedures for a simpler eyepiece. In my case, a barlow lens that I cleaned with alcohol and some of it wicked inside and fogged the lens edges.

Perhaps a new chapter for the 2nd edition of your book?


Post Extras: Print Post   Remind Me!   Notify Moderator  
BillP
Postmaster
*****

Reged: 11/26/06

Loc: Vienna, VA
Re: A how-to for eyepiece disassembly/cleaning? new [Re: precaud]
      #6320413 - 01/18/14 12:32 PM

Many of the Barlow lens elements are cemented doublets and the lens housing unscrews from the bottom. On one end of that you will see a retaining ring with two notches in it. A special tool called a spanner wrench is places in the notches and it is simply unscrewed. Once out the lenses are now loose and you can extract them with a vacuum tool or hold them in place with a finger, invert, and let gravity have them slip out...being careful not to drop them.

If you have a standard Barlow with a cemented doublet then any excess fluid not going anyplace that matters since the doublet is cemented together. However, if you have a triplet then there is probably an air gap and spacer between so the invert to get them out I dangerous as the assembly can separate and lenses then falling. So lots of care necessary if you don't have the proper tools. So like any home fixing, proceed at your own risk and if you go into it accepting that it's ok to ruin it, then you are not heartbroken if you do. When I take my stuff apart my attitude is that it's ok if I mess it up. If it's not ok, then I leave it alone.

Whose Barlow do you have?


Post Extras: Print Post   Remind Me!   Notify Moderator  
precaud
scholastic sledgehammer
*****

Reged: 12/05/12

Loc: north central New Mexico
Re: A how-to for eyepiece disassembly/cleaning? new [Re: BillP]
      #6320573 - 01/18/14 01:44 PM

Thanks for the overview, Bill. Spanners I have or can easily fab. What sort of "vacuum tool" do you use for extraction?

The barlow in question is Meade 140 triplet. I read a post from a few years ago where someone took theirs apart and blackened the edges, so I figured it can be done...


Post Extras: Print Post   Remind Me!   Notify Moderator  
BillP
Postmaster
*****

Reged: 11/26/06

Loc: Vienna, VA
Re: A how-to for eyepiece disassembly/cleaning? new [Re: precaud]
      #6320715 - 01/18/14 03:12 PM

There are several brands of these vacuum tweezers. Here's on - link.

These inexpensive vacuums are life savers...especially for small eyepieces like the 7mm Pentax SMC Ortho I just took apart for cleaning. It was a snap with this tool.

Oh yes...and good to have acetone around, got mine from Home Depot. Many makers seal the threads so they don't come lose or so people like me don't tamper with then. Acetone dissolves the seal.

And finally...you void warranty when you do this. So again...at your own risk.

Edited by BillP (01/18/14 03:21 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
dan_h
Carpal Tunnel


Reged: 12/10/07

Re: A how-to for eyepiece disassembly/cleaning? new [Re: BillP]
      #6320979 - 01/18/14 05:46 PM

The other major problem is dust. You may think you don't have any, and you may be very careful, but somehow, this stuff always gets into the airgaps in an eyepiece or Barlow. Always.

dan


Post Extras: Print Post   Remind Me!   Notify Moderator  
precaud
scholastic sledgehammer
*****

Reged: 12/05/12

Loc: north central New Mexico
Re: A how-to for eyepiece disassembly/cleaning? new [Re: dan_h]
      #6321001 - 01/18/14 05:58 PM

Thanks Bill, I'll look into one of those pickup tools. Having ruined one eyepiece last spring while attempting to "fix" it, I'm aware of the risks...

Quote:

The other major problem is dust. You may think you don't have any, and you may be very careful, but somehow, this stuff always gets into the airgaps in an eyepiece or Barlow. Always.




Dust? In New Mexico? Surely you jest!


Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: A how-to for eyepiece disassembly/cleaning? new [Re: precaud]
      #6321069 - 01/18/14 06:39 PM

Quote:

Thanks Bill, I'll look into one of those pickup tools. Having ruined one eyepiece last spring while attempting to "fix" it, I'm aware of the risks...

Quote:

The other major problem is dust. You may think you don't have any, and you may be very careful, but somehow, this stuff always gets into the airgaps in an eyepiece or Barlow. Always.




Dust? In New Mexico? Surely you jest!



Note that dust motes on lenses are MORE visible when closer to the focal plane of the eyepieces. If the eyepiece is a compound design (negative lens in bottom, positive group up top), the focal plane is probably in-between and you need to take steps to make sure those two facing lens surfaces are scrupulously clean.


Post Extras: Print Post   Remind Me!   Notify Moderator  
precaud
scholastic sledgehammer
*****

Reged: 12/05/12

Loc: north central New Mexico
Re: A how-to for eyepiece disassembly/cleaning? new [Re: Starman1]
      #6321113 - 01/18/14 07:09 PM

Thanks Don, I'll keep that in mind if I undertake it.

BTW, I just found the post, it was you who took apart a 140 to blacken the edges:

http://www.cloudynights.com/ubbarchive/showthreaded.php/Cat/0/Number/767764/p...


Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: A how-to for eyepiece disassembly/cleaning? [Re: precaud]
      #6321196 - 01/18/14 08:18 PM

John,
Wow. Must've used the Wayback machine.
It's a lot easier on a barlow, of course, with only one or two lenses.
But seriously, a shiny interior? Hand crafted by non-astronomers, no doubt.


Post Extras: Print Post   Remind Me!   Notify Moderator  
precaud
scholastic sledgehammer
*****

Reged: 12/05/12

Loc: north central New Mexico
Re: A how-to for eyepiece disassembly/cleaning? new [Re: Starman1]
      #6321880 - 01/19/14 10:04 AM

Don, Google advanced search is a wonderful thing!
Yes, one has to wonder what (or if) they were thinking. The 140 I picked up is blackened inside, but it's a glossy black. It seems reasonably sharp but has color fringing issues on Jupiter.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: A how-to for eyepiece disassembly/cleaning? new [Re: precaud]
      #6321902 - 01/19/14 10:25 AM

Quote:

Don, Google advanced search is a wonderful thing!
Yes, one has to wonder what (or if) they were thinking. The 140 I picked up is blackened inside, but it's a glossy black. It seems reasonably sharp but has color fringing issues on Jupiter.



On axis? Bet the lenses aren't spaced right. Or was this a variation in QC on the production? Hard to say.


Post Extras: Print Post   Remind Me!   Notify Moderator  
davidpitre
Post Laureate
*****

Reged: 05/10/05

Loc: Central Texas
Re: A how-to for eyepiece disassembly/cleaning? new [Re: Starman1]
      #6321943 - 01/19/14 10:50 AM

I've never had or seen an eyepiece taken apart and put back together that did not get some dust between elements, Outside of a clean room, it is extremely difficult.

Post Extras: Print Post   Remind Me!   Notify Moderator  
precaud
scholastic sledgehammer
*****

Reged: 12/05/12

Loc: north central New Mexico
Re: A how-to for eyepiece disassembly/cleaning? new [Re: Starman1]
      #6321974 - 01/19/14 11:04 AM

Quote:

Quote:

It seems reasonably sharp but has color fringing issues on Jupiter.



On axis? Bet the lenses aren't spaced right. Or was this a variation in QC on the production? Hard to say.




I'll doublecheck if it's clean on axis next viewing session. But I can say, it's the worst of any barlow I've tested.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: A how-to for eyepiece disassembly/cleaning? new [Re: precaud]
      #6321993 - 01/19/14 11:21 AM

Quote:

Quote:

Quote:

It seems reasonably sharp but has color fringing issues on Jupiter.



On axis? Bet the lenses aren't spaced right. Or was this a variation in QC on the production? Hard to say.




I'll doublecheck if it's clean on axis next viewing session. But I can say, it's the worst of any barlow I've tested.



Interesting.
I compared mine with a Japanese Parks Gold Series (same as Celestron Ultima), a TeleVue 2X, and a Klee 2.2X (?), and kept the Meade 140 because mine was sharper than the other ones. I've owned a lot of barlows and would have put it in the top 5 barlows I've owned.
There must have been major QC issues with that one.


Post Extras: Print Post   Remind Me!   Notify Moderator  
BillP
Postmaster
*****

Reged: 11/26/06

Loc: Vienna, VA
Re: A how-to for eyepiece disassembly/cleaning? new [Re: precaud]
      #6322035 - 01/19/14 11:55 AM

Quote:

The 140 I picked up is blackened inside, but it's a glossy black. It seems reasonably sharp but has color fringing issues on Jupiter.




I may be misinterpreting your post, but when the interior of the Barlow barrel in reflective, the result is usually some flare and/or glare that washes out the contrast in the FOV when bright objects are appropriately positioned. I can't think of a circumstance where color fringing would ever be a result as this is an optical aberration. I've seen lots of Barlows induce or increase lateral color in an eyepiece (i.e., the optical elements of the Barlow cause this). I suppose they (the optical elements) could also induce axial color as well, but that I've not seen.


Post Extras: Print Post   Remind Me!   Notify Moderator  
precaud
scholastic sledgehammer
*****

Reged: 12/05/12

Loc: north central New Mexico
Re: A how-to for eyepiece disassembly/cleaning? new [Re: BillP]
      #6322070 - 01/19/14 12:14 PM Attachment (11 downloads)

Bill, I didn't mean to infer that the reflective interior was causing the fringing. I thought it might be lens misalignment and started a thread asking about that, but got no replies. I was cleaning a spot off near the edge of the inside lens when I caused the problem I'm now trying to solve.

Don, I suspect you're right in the QC issues. I should have examined it more carefully before giving the seller the ok.

Anyway, here is the pic of the edge whitening caused by the alcohol that wicked in between the lenses.

I also noted that the gasket seen just inside the outer lens element is not black, but grey. Seems like an odd choice to me.


Post Extras: Print Post   Remind Me!   Notify Moderator  
BillP
Postmaster
*****

Reged: 11/26/06

Loc: Vienna, VA
Re: A how-to for eyepiece disassembly/cleaning? new [Re: precaud]
      #6322175 - 01/19/14 01:10 PM

That just looks like alcohol drying marks on the blacked edges, or possibly some dissolving of the lens edge blackening. No biggie IMO and more cosmetic probably.

Again, if this is a doublet then an easy fix to just unscrew that retaining ring. Then carefully holding pressure on the lenses with your fingers (using a cleaning cloth), invert the unit and then grab the doublet. Then just clean the edges and use flat black paint or a black sharpie to re-blacken. If you use a sharpie, excess alcohol will dissolve it, but only a very minor amount. FYI, I used a sharpie on a test lens then did several excess alcohol spills over it and it never took the black off, but the excess running alcohol was very slightly tinged from runoff of the black.


Post Extras: Print Post   Remind Me!   Notify Moderator  
precaud
scholastic sledgehammer
*****

Reged: 12/05/12

Loc: north central New Mexico
Re: A how-to for eyepiece disassembly/cleaning? new [Re: BillP]
      #6322349 - 01/19/14 02:38 PM

Yes, that's exactly what it is, as I described earlier. The 140 is an air-spaced triplet, hence my caution.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1 | 2 | (show all)


Extra information
10 registered and 30 anonymous users are browsing this forum.

Moderator:  ausastronomer, Scott in NC, iceblaze 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 965

Jump to

CN Forums Home


Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics