I have made one, using thin glass fibres from optical cable (not easy to find these days, modern fibres are mostly plastic and not thin enough).
First I had to drill the guiding holes (0.3mm drill) in the focal plane.
The fibres were glued in place with 5 min epoxy on only one end. They are straight enough and rigid so no need to stretch them.
In the past, people used spider fibres for the purpose (from young spiders, they are stronger and thinner).
The treatment with water makes them black, but I am not sure about details yet, I will investigate a bit....
Have a look at: http://www.surveyhistory.org/cross-hairs1.htm
Sorry I can't offer much, but I hope you'll let us know how you get on on this little project. It sounds interesting.
I bought my old 8"Newt second hand from an elderly gentleman in St Ives in Sydney about 25 years ago. Amongst the stuff that was in it was a home made reticle. From memory it was two crossed wires (very fine) soldered into a ring made from brass shim. It slid up the inside of the eyepiece - the threaded bit where the filters screw in. I remember being impressed with his fitting skills, but I can't remember how it stayed there now... Time has dimmed the memory...
I've got some extra fine copper wire ex-pocket radio transformer which has been successfully used for various cross wire eyepieces over the years. PM me for sample.
Used stretched aeroplane glue with some success ( and failure!!)
A small cardboard diaphram with the cross lines marked on it, cut to suit the eyepiece and Tarzan grip is all you need. If you have a "spare" eyepiece you can drill a 4 - 6mm hole in the side opposite the field stop and glue in a Red LED works well!!!
I came across this thread, and I thought I'd add what I've done to an old eyepiece to make a Celestron FirstScope a big finder.
It's an old Celestron 25mm Kellner. I found the focus of the eyepiece sat inside the main body, a little infront of the field lens. Using a little high school geometry, I gauged its center and drilled four tiny holes into the eyepeice at the centre points to the place of its focus. I drilled an extra hole next to each centre hole to loop some copper wire.
The copper wire can from an old telephone lead. I found this to be the thinnest at my disposal, at around 0.1mm in diameter. The wire is looped around one pair of holes, threaded through the eyepiece and wound around the opposing pair of holes. The process is repeated for the other set of holes. Epoxy glue holds the loops in place.
The first picture shows the image through the eyepiece and the second wires in place within the eyepiece with the 1.25" barrel removed.
It is unilluminated, but in an f/4 scope, no illumination is necessary as the background sky glow is sufficient to show up the crosshairs.
i got a hot glue gun and pulled it out till it was very fine then a few dabs of super glue and it was perfect.
The good thing about it was that when the starlight hit the strands you could see it very well as it illuminated the hot glue strands. i still have it today
The 240V globes have glass tube on which the holders for light emitting wire are mounted.
I heated this glass tube in the middle on alcohol flame, and when it became soft enough I pulled two ends apart, quickly.
After some practice (and many broken bulbs) I managed to make two glass fibres, thin enough to be used in eyepiece.
However, optical fibre is much better..
I have made one, using thin glass fibres from optical cable (not easy to find these days, modern fibres are mostly plastic and not thin enough).
I terminate fibre cable all the time, believe me, it's not plastic nowdays, it's still made of glass.
Fibre cable comes in 2 types, loose tube and tight buffer. Both have a plastic coating which has to be carefully scraped off the fibre. The loose tube variant has a thin coating, the tight buffer has a double coating and is much thicker, but still the same diameter once stripped. I have a special stripping tool which does it, but they're over $100.
I suspect that the buffer could be removed from the loose tube variant with some solvent.
If anyone would like some short pieces of fibre, PM me out, I can supply for free, you supply a Stamped Self Addressed Envelope.
I terminate fibre cable all the time, believe me, it's not plastic nowdays, it's still made of glass.
Actually, I do it these days as well.
My first post was when I was still working for NEC.. and I could not get gold of the fibre, because I worked in wrong department/division :-)
Currently I am with PBN, and I am dealing with glass fibres on the daily basis :-)
Coating stripping (it looks like silicone) I can do with scalpel under the microscope.. fiddly but very much possible and quick procedure.
First, many thanks to acropolite for the bundle of optical fiber, .
Resulted that the EP I had to make a reticle for couldn't be wired like the first one I made. The field stop in this 25mm Super Plossl is positioned at the focus of the EP. All I had to do was measure the widest diameter of the stop's span and cut two optic fiber lengths to this length. I then drilled out undercut ledges to sit the fibers across the span. The undercuts help give some mechanical retention to the epoxy glue used to fix the fibers, lest the hold of the glue fail, the undercuts will hold.
The first picture shows the EP with its barrel removed for access to the field stop. The tiny undercut holes were done using a 'Dremel' type tool. The second pic show the barrel restored and how well protected the delicate fibers are.
I made one 30 years ago using spider web. I had a spider on a coat hanger and moved it off with a pencil and as it was hanging there I wound the web with the coat hanger.I then put some glue on a brass washer and the spider web stuck to it. I created an x on the washer.
Then it was a matter of sliding the washer into the finder scope's eyepiece focal point. It worked well and was a very fine x that seemed to illuminate well with planetary or star light.
Mind you at 20 my eye sight was very good.
I too, many years ago built a cross hair reticle using thin, single-strand wire from somewhere (possibly a heater or electric blanket coil ) and applying a small current to it, getting it to give off a faint red glow.
Very crude but it worked. I may not be the preferred method these days, however.
Quote:
Originally Posted by DavidU
I made one 30 years ago using spider web. I had a spider on a coat hanger and moved it off with a pencil and as it was hanging there I wound the web with the coat hanger.I then put some glue on a brass washer and the spider web stuck to it. I created an x on the washer.
Then it was a matter of sliding the washer into the finder scope's eyepiece focal point. It worked well and was a very fine x that seemed to illuminate well with planetary or star light.
Mind you at 20 my eye sight was very good.
I too, many years ago built a cross hair reticle using thin, single-strand wire from somewhere (possibly a heater or electric blanket coil ) and applying a small current to it, getting it to give off a faint red glow.
Very crude but it worked. I may not be the preferred method these days, however.
David, what is your preferred web? Funnel web, redback, white tail, daddy longlegs?
Imagine the reaction from a guest having a look through the reticle EP and at the same time being told "Oh, it's Funnel Web spider fiber from the nest just down there next to your ankle"!!!
David, what is your preferred web? Funnel web, redback, white tail, daddy longlegs?
Imagine the reaction from a guest having a look through the reticle EP and at the same time being told "Oh, it's Funnel Web spider fiber from the nest just down there next to your ankle"!!!
home made reticle eyepiece
Thanks for the link mate
).
will check it out now 
