Micrometer eyepiece for astrometry

(Brian Tung) wrote in message ...
Thad Floryan wrote:
In principle, yes (esp. the filar one), but note:

"... can be clamped on any eyepiece tube with an outside diameter of
25mm or less. The graduated micrometer knob drives the crossline
across the field of view. The precise mechanism assures smooth
operation and accurate measurement of objects under the microscope.
One full revolution of the micrometer knob corresponds to 1 mm of the
crossline movement."

It ain't gonna clamp on any of your standard 1-1/4" telescope
eyepieces.

Possible solution: Buy a 1.25-to-0.965 adapter, buy a high-quality
Takahashi 0.965-inch eyepiece, then buy the filar micrometer.

Unfortunately all the commercially available 0.965:1.25 adapters I've seen
are barreled for the opposite: adapting a 1.25" device to a 0.965" system.

Here we'd want to adapt a 0.965" device to a 1.25" system with two barrels,
one to slip into a 1.25" hole and the other as a clamp-point for the filar
micrometer.

Someone posted some current pricing of "native" filar micrometers and IIRC
the price was circa US$1,000. Ugh. Easier to CCD everything and perform
the measurements on a computer.

For "coarse" measurements at the eyepiece, something like Meade's astrometric
reticle EP would work after it's calibrated to the scope (noting it can be
rotated in the holder to facilitate, say, separation measurements).

Thad Floryan wrote:
Unfortunately all the commercially available 0.965:1.25 adapters I've seen
are barreled for the opposite: adapting a 1.25" device to a 0.965" system.

Ahh, that's too bad. I think Orion *used* to sell one that went the
other way, but I guess they don't anymore.

Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt

"Brian Tung" wrote in message
...
Thad Floryan wrote:
Unfortunately all the commercially available 0.965:1.25 adapters I've
seen
are barreled for the opposite: adapting a 1.25" device to a 0.965"
system.

Ahh, that's too bad. I think Orion *used* to sell one that went the
other way, but I guess they don't anymore.

Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt

I found this site:

http://www.digitalastronomy.com/html...e_adapters.asp

Best regards,
Bill

Bill Becker wrote:
I found this site:

http://www.digitalastronomy.com/html...e_adapters.asp

What?! Being resourceful? Is that allowed? There oughta be a law!

Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt

On 2 May 2004 15:28:09 -0700, in uk.sci.astronomy , (Thad
Floryan) wrote:


Unfortunately all the commercially available 0.965:1.25 adapters I've seen
are barreled for the opposite: adapting a 1.25" device to a 0.965" system.

isn't it pretty easy to make your own for going the other way? Get an old
EP w./olenses, (or use a 35mm film pod?) pack internally w/ a foam rubber
ring, you could push the 0.965" ep into the hole and the foam would hold it
firmly

--
Mark McIntyre
CLC FAQ http://www.eskimo.com/~scs/C-faq/top.html
CLC readme: http://www.angelfire.com/ms3/bchambless0/welcome_to_clc.html


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Ahh, that's too bad. I think Orion *used* to sell one that went the
other way, but I guess they don't anymore.

Actually Orion sells an adapter that will allow the use of 0.965 inch eyepieces
in a 1.25 inch focuser as well as an adapter that will allow the use of a 1.25
inch eyepiece in a 0.965 focuser....

http://www.telescope.com/shopping/pr...mID=150&itemTy
pe=PRODUCT&RS=1&keyword=eyepiece+adapter


jon

For the .965" to 1.25",. all that is needed is a ring just like the larger
one that adapts 1.25" EPs to the 2" focuser. These are easily made if you
have access to a lathe so there shouldn't be any problem making one if you
need to.

--
Bob May
Losing weight is easy! If you ever want to lose weight, eat and drink less.
Works every time it is tried!