Jump to content


Photo

Meade 1000mm f11 lens disassembly and cleaning


  • Please log in to reply
4 replies to this topic

#1 Ken

Ken

    Newbie

  • Members
  • Pip
  • 3 posts

Posted 05 March 2013 - 07:28 PM

I bought a used 1000mm and due to improper storage there is a lot of dust in the interior. I want to open it, and clean it but can not find any information on doing so. I know some say do not worry about dust because of the focal point, others say if you open it you will ruin collimation, but this is a fixed mirror lens, no setting available. I have removed the 3 base screws, and the shoe screws, but it's tight as a drum.
Can anyone help me or point me in the right direction?
Thanks in advance.

#2 MistrBadgr

MistrBadgr

    Advanced Member

  • Administrators
  • 1987 posts
  • LocationBroken Arrow, Oklahoma

Posted 06 March 2013 - 05:10 PM

Hi Ken,

Welcome to the forum!

Is this a refractor (lens in one end and focuser in the other), a newtonian reflector (an open end with a mirror inside at the other end, and a focuser on the side near the open end), or something like a Schmidt Cassegrain, (has a mirror in the rear, a corrector lens in the front with a mirror in the middle, and a focuser on the rear end)?

If you can take a picture of the ends and attache them to a post, it would help.

I am assuming this is a refractor, but I want to make sure.

Thanks,

Bill Steen

#3 Ken

Ken

    Newbie

  • Members
  • Pip
  • 3 posts

Posted 06 March 2013 - 05:27 PM

Same as this, just black body

http://forums.dprevi...ms/post/5643431

#4 MistrBadgr

MistrBadgr

    Advanced Member

  • Administrators
  • 1987 posts
  • LocationBroken Arrow, Oklahoma

Posted 06 March 2013 - 08:04 PM

Oh, Wow!!

The only time I have ever seen something like that was when I worked in a camera store while in college, about 40 years ago. Those things were just then starting to come around. An optical company rep showed up with one as a demo to show the store owners.

I really do not know if you can pull that apart. A lot of that kind were actually glued together as well as having screws to hold things in place while the glue set up. I do not know if the one you have was glued.

If the glass in front is thin, it is a Schmidt Cassegrain. If the glass is thick, which is what I am gathering from the picture, it is a Maksutov Cassegrain.

The people that told you not to pull it apart are most likely right. If you pull it apart, I believe it will require luck rather than skill to get it back together an have an image as good as it has now. What I would do is try to blow any dust inside out using a can of compressed gas, like you would use to clean a computer keyboard. I would be careful to keep the can upright, if there is liquid in the can. I would only blow gas until the can starts to get cold, then I would stop and come back and do some more the next day. Just keep working it and spray all around inside, from the camera end, until you get the dust out.

Some form of dry air would actually be best. If you get stains on the inside, you are just fixed.

On the outside, I would blow off anything that can be blown off, then try to get any smudges with dry, clean cotton swabs. Just work gently on a spot for a little bit, then throw that swab away. A drop or two of distilled water can be used on the outside, but I would avoid anything harsh on the lens or you might mess up the coatings. Possibly, since this is actually a camera telephoto lens, it is built to let you use Kodak lens cleaner and lens cleaning tissue. I would not put any real pressure on the lens surface. Gentle action and patience is better.

What you have there could end up being a real collector item if it is not all ready.

If you really want it pulled apart and cleaned, I would seriously consider sending it to a real camera repair shop. You might even call Meade Customer Support and talk to them about it. Since the whole Meade Shop moved since your lens was built, they may not know much about it, but I believe they would be able to work on it with a little help from experts from headquarters, if they will. I have no idea what it would cost.

If you do want to take it apart and it is not glued together, most likely then outer retaining ring on the forward end is threaded in and has to be removed with a spanner wrench. I suspect that you will need to look for any kind of marks on the edge of the corrector lens in front as you take it out and keep the lens oriented exactly the same way (rotationally) going back together as coming apart. I would be reluctant to try to remove the mirror. I would just to touch-ups on it in place.

Hope this helps,

Bill Steen

#5 Ken

Ken

    Newbie

  • Members
  • Pip
  • 3 posts

Posted 06 March 2013 - 08:09 PM

Excellent reply Bill, thank you so much.

I looked though it today and was amazed at how clear it is.

I reinstalled the screws, will dry to blow out a little dust gently as advised. Thank you again,




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users