Chriske

I always try to hide wires in project like this. It looks better. In this case I need to hide the wires of the laser(sitting in front of the eyepiece holder). I need to make 'corridors' in the parts itself. For my laser there was no other way than to lead the wiring very close to the top of that part. After installing the laser I cover the corridor with a very narrow ring.

Mounted on my printed telescope.

This a drawing I made showing the completed unit from different angels. The bleu parts I do print these. Years ago when I did not had that 3D-printer yet we use to make them out of resin. If you decide to use these BD601 units and you have printer, let me know, I'll send you the STL files. The large knob is the 1:1 and the smaller one is the 6:1 Almost forgot, to fasten the large knob you need two M2 screws(they're not included)

Hey, You beat me to it... These are the ones I was referring to. The one I always use BD601 only cost a bit more indeed then the last time I bought them(years ago). That is if you buy them 5 at once (12$). Years ago they only cost 10$ a piece, I'm a bit surprised price got up that much. They work very well BUT! You need to take them apart completely, take out the thick grease and reassemble them adding a bit of light lubricant. + release a bit of the pressure of the little lips that hold these units together. The BD601 units are stamped versions, so not the same quality as the machined versions. But again modifying the BD series a bit and they work just as perfect I suppose. I always bought them by the dozen or so because we needed these for our telescope-making-course. If you buy the BD601 let me know, I have some pictures how to take them apart and reassemble again. Reassembling is done with a bit of 'fingerspitzengefühl'. You should not press to hard on the assembly-lips to close the unit again. There are dozens and dozens in use in our telescopes at our observatory, they work just fine. One more thing : If you need both speeds 1:1 and also 6:1 you should buy the BD601 unit. The BD602 has ONLY the 6:1 reduction, there's no flange to attach the 1:1 knob. Never tried the machined version myself, maybe they're far better. If you buy that one, please let me know, maybe I'll try that one also. Good luck. Chris

I use dual speed knobs in almost all my scopes. I buy these units in US, costs about 10$. And no there's no backlash at all in these units. Need to look it up, forgot where I bought them.

Indeed Robert, All is done in Inventor. It's an old one. I got it from my employer about 10 years ago. Still use it every single day. It was in fact part of my job. Although it's an old one it does what it's suppose to do and more... The most rewarding item is 'Assemblies'. It gives you the ability to see in and outside to inspect the project. It also detects collisions if needed. There's also a strain-detector. There's in fact to much to mention...love it. There's only one minor point. It does run only in Win.(I'm Linux user) So I run Inventor in a VirtualBox. Using it in a VB I don't see any difference, it's in fact as fast as in a 'normal' Win.

I know, but I love this kind of stuff..., I love the challenge. It's a rewarding instrument. It beats a long refractor of the same size easily.

The secondary holder needs a angled cut to allow free passage of incoming rays from the sky to the primary mirror. It's a very close fit. The very last thing after collimation is to free that incoming lightpath from the secondary holder. To do this one of the adjustment screws of the primary mirror must be installed in the meridional plane. When done the angle of the primary mirror is automatically correct(ed).

Cutting the oblong hole in the secondary tube. That hole is in fact a cone shaped cut in a cylinder. Even in Inventor not an easy task. For every other Kutter that oblong hole is different. But once I have that drawing, I can print that part of the tube to use that printed part as guide to draw that hole on the StSt tube itself. To be sure I need to enlarge that hole a bit, taking care the light-path coming from the primary is not partly blocked.

Hi, Lots of things have changed these last days while drawing. First of all I've added three fans to cool the scope very quickly. Powerpacks in the scope. It's a near open scope, so it's handy to dry optics with these fans if necessary. Added also is a laserpointer. These scopes are very difficult to aim without an aid. (I never use finderscopes) - ( I use my lasers very cautiously, never point at people, planes, etc. And when I lit them it's only for a few seconds. It's tool, not a toy..!) It's not a classic focuser. I didn't want to mount a large focusing-device on top of that most upper tube. So I designed a Crayford-like focuser. I call it : 'Inversed Crayford'. (Maybe it's been done before, don't know) The focuser is nothing more than a tube containing 6 ball-bearings and a focusing rod. In fact just the same as a regular Crayford. Point is, while focusing I move the focuser itself +eyepiece up and down. This way it has a more 'elegant' look. That eyepiece sits angled in it's focuser, it's part of that Kutter design. Eyepiece is tilted 3.86° away from the observer. To insert the eyepieces I'll be using on-axis adapter. Purpose is to mount eyepieces in the exact centre of the optical train. So there's no thumbscrew required at all. These adapters are 'springloaded' in both ways, in- and outward. Also own design. That's it for now, still some more drawing to do...

It's not very difficult to make this type of telescope. There are a few different types of Kutters. Actually the one I'm making right now is not really a Kutter telescope, it is called a Neo-Brachy telescope. Kutter read about it and improved the concept. The most important change he made was adding a correcting lens between secondary mirror and eyepiece(somewhere in the middle). The Brachy version I'm making is a anastigmatic one. Advantage of this type is : There's only one mirror-set to make. Meaning the concave mirror is the primary(of course) and the tool is used to make the secondary. Both mirrors have the same curvature and on top of it both these mirrors can stay spherical. A Kutter's primary mirror on the other hand is a parabola(50%), so in fact elliptical. The secondary can stay spherical. The corrector is a plano-convex lens. Convex side is very shallow, and that lens is also wedge shaped. There are other possible configurations but the one I'm building right now is the closest to the Kutter version. I do like it very much. Unfortunately these 'planet-killers' can't be taken outside very often. They need steady skies. If the atmosphere is quiet and steady they will give you breathtaking superb images. Nothing can compare with it..! Because of it's long focus contrast is very high. In the past I've already made a couple of these scopes mostly 150mm. Disadvantage is it's size. A Brachy is always on the long side. I also made this one almost 2 years ago. I also was busy making a bino version of that one, but it's on hold now. It will look like this :

Good optics too that yolo. In the early days I've written to Mr Leonard. Was no mail in those days. Same as the other long scopes.. This one is not 12" but a 6"

Optics well done en tuned these Kutters are superb telescopes. In our local observatory there use to be a 10" version. Focal length 5 meter. Moon at primary focus fitted just on the negatives of my 6x6 camera. It was a 'real' Kutter. To correct residual coma and astig there was a correcting lens installed tilted about 20°. Focal plane is tilted about 7°. As you can see in the drawing, Focal plane of my 120mm kutter is tilted almost 4°, also to correct residual errors. But not all is corrected(there's no correcting lens in mine) But all ray's stay well within the Airydisk, no problem there. Another one one my wish-list is a Gregorian. Two concave mirrors, one is a parabola and the secondary is an ellipse. Gregorian 150/f25 Compared to a (very long)Newt of the same size F=2000mm

f/31, so planetary and Moon observations only. Busy grinding the optics. And at the same time designing the telescope itself. This is V1. The light leaving the secondary tube passes through the primary tube at an angle of 11.30° The yellow transparent cone is to guide me where I need to cut that oblong hole in the secondary tube. The focuser is a new design that has never been done before. It goes up the small upper tube. I'm not planning using 2" eyepieces at all in this scope.

It will be difficult I think because of that big hole. These printers can handle straight bridges, but in your case a bit of that circle will sag.

You'll need a bit of support if you print it this way. Looks good..

Was away, looks so much better..!

Indeed....but....

It has noting to do with weight Gina, not at all...! I'm always very careful myself when designing such a clamp. Point is : When the screw is fastened a bit to tense the upper part could break. Maybe not the first time, but in time it could break. To be strong in the direction the screws are mounted you should print it in the opposite direction. Whatever you do, how hard you turn that knob, there's no way it will ever break. Maybe, just maybe it well bend, but it never will break. I would not over-engineer it at all myself either, but I would print it in the other direction, logic, not..? If it were a part of no importance I(maybe) would print it just the same. But in this case, well....

Not a good idea imo Gina, to make this clamp very strong you need to make it in three parts and bolt together.

How so..?

Resin for these printers is rather expensive ? 1kg(750ml) : 79€ 1kg of PLA 19€ Yep, I'll stick to FDM too...

Dave, Why not just build a very small printer yourself..? Like I said higher up in this thread, my pall Marc has built one. Max printable part 100x100x100. I just finished building exactly the same as Marc, except this new one can print 100x200x130mm max. I've built it for a friend, Who's planning to use it exclusively for modelling train-parts. He will be using it with 0.25 and 0.15mm nozzles only. This very moment there's a 0.4mm nozzle installed. Walter(the new owner) never used a printer before, so he has to master the skill first. After a while he can change to smaller nozzles. In this extruder I designed a fast swappable E3D hotend. So he only needs to remove the parts-cooling-duct(2screws) and the hotend itself(2screws) and that's it.

Come on Gina, a bit of fantasy and you could install a nano-printer inside a 2.2kg ColorFab reel. Lots of space there... And to have some flexibility I would allow some parts to stick out of the reel...

My pal Marc made a printer able to print 4 inch cube max. I know, not answering the question, but at least my sentence contains '4 inch cube'... It's a gorgeous little thing and does work very well.