Chriske

We often shared files, Gina and myself Gina's giant clock was one of here favourite projects. She printed it on here 'Giant printer'. She sent a copy of here clock(she drew it her self..!!) to me. If I'm not mistaken it has a diameter of nearly 500mm It used a small stepper...

You're going to enjoy this big bino. Observing with these large binos has many advantages. Simply said, you see much more compared to a 'singles scope'. I've built a few binos myself...😉 To me, as a mechanical engineer, there's a high drooling factor involved in what you construct...👍

Thanks John, Nice tool..!

David, I'll be using that 'Plossl' in combination with a 150mm refractor f15.7. So primary image of the Sun will be about 24mm. I'll project the image of the sun on a white screen. I'll be refocusing until I have a very large sun on that screen. So if the combined FL of that Plossl is 90mm it has no effect on the projected image. Visual observing would indeed give me a very low magnification. But I will not use it for visual observing at all. The most important reason why I use these large lenses, and as a Plossl combination, is to avoid heating up that eyepiece while projecting the sun. Thanks for the input. Still have to learn about these self-made eyepieces...;-)

Did not know where to post, so I also posted in the eyepiece section. Hi, Just finished building an eyepiece and I was surprised it worked, and it worked rather good as a matter of fact. It was a quick test using a refactor with a 1 1/4 focuser, handhelding that eyepiece. So I could not see the entire FOV. From what I've read the acromats should be placed as near as possible, front lenses pointing to each other, so I did. I made a holder in which I could change the spacing between the two. Observed a large post at about 300m distance : in both occasions, lenses very near and also at about 60mm apart the result is just the same. How is that possible...? Lenses 50mm diameter(was a binocular) F=180mm Thanks...

Just finished building an eyepiece and I was surprised it worked, and it worked rather good as a matter of fact. It was a quick test using a refactor with a 1 1/4 focuser, handhelding that eyepiece. So I could not see the entire FOV. From what I've read the acromats should be placed as near as possible, front lenses pointing to each other, so I did. I made a holder in which I could change the spacing between the two. Observed a large post at about 300m distance : in both occasions, lenses very near and also at about 60mm apart the result is just the same. How is that possible...? Lenses 50mm diameter(was a binocular) F=180mm Thanks...

Done and ready to use it in two ways... This position is to observe.. and this is the 'other' position...😀

Optically it performs rather good, as a matter of fact I was a bit surprised. To be clear it is not a optical masterpeace, I made 'a few' better mirrors in my lifetime. Visitors at our open door will not see the difference between a perfect 'bottle' and mine...😉 Problem during polishing and figuring a square @ f/4 (about) there's no ideal way of polishing a square mirror on a circular lap. Or is it...?...😄

Well, as a matter of fact when my friend, who loves Bokma gin, saw my little scope for the first time he started grinning and a few days later he gave me another set of (empty)Bokma bottles. He said, I know you like to build bino's, so make me one please... Needles to say ...I'm tempted...very...😄

Well, this is how I rebuild this little scope. Much nicer then the old one. It has more elegance with these printed parts imo... I added a few items : -It has a Helix focuser running 6 ball bearings. -The dispenser is an improvement imo...😉 -The 'primary mirror' has a very smooth collimation system. -The only thing to do is adding a light shield opposite the eyepiece. -and yes, I need to glue a new 'Bokma' label at one side of the 'telescope'. -Problem is... I don't like Bokma at all. But I suppose I could fill it up with something else, like Martini...? After silvering I had a quick peek through it (after 30+ years) and I must say I was very pleased with the quality of this little 'scope' This little scope has a square mirror and also a square secondary, so now the million dollar question : Will I see square diffraction patterns...???...🔷 😄

Two mirrors silvered today. We used the 'Spray silvering technique'. Works fan-tas-tic..! This is my buddy Fred blowing off the last water drops. It takes about one hour to finish a 400mm mirror.

Only the flat is tilted toward the sun and projects the solar light toward the spherical. The spherical and screen are parallel

screen projection, no filter

The size of the sun is about 470mm. Marc who made the primary mirror aimed at 40 to 45m focal length. Measuring was done with a 120mm diameter spherometer. The goal was grinding to 0.022mm on the dial gauge, but I suppose during MOT he ended up with a longer FL. But that's ok the sun will be a little bigger, we don't mind. For both mirrors there's no tube involved at all. The screen has a nearly 1m tube hanging about 2.5m high. That tube is blackened at the inside and has a oblong hole at the bottom to allow the observers to see the sun from standing position on the pavement. I'll post some more pictures very soon. The setup is very simple. This drawing is NOT to scale, in this drawing both mirrors should be farther away from each other. The flat and the screen are very near (at left). The spherical at right is also standing at 2.5m high. This test setup was only to find its FL. The mirror stands on a very old Vixen mount. The tapes will be replaced with strong hooks of course.

Busy making a solar'scope'. Optics nearly done, only silvering of the two optical parts needs to be applied. There are three parts involved, one 400mm diameter flat, tracking the sun, one stationary spherical mirror (400mm f/137.5) and a 500mm square white screen. All parts are mounted just high enough so the spectators(during open door at our observatory) cannot walk through the light beams. Both mirrors will be silvered to achieve maximum reflection. Tracking the sun will be done using an old Vixen mount.

Almost finished...

These will be hung aside our 1:10 scale Orion capsule. One more to go. I know not the correct suits but it has to do for now. They will be replaced in the near future. Working, working, working....

Busy redrawing using a 3mm pitch...

Need to adjust my callipers... ...or my eyesight...😃 🥸

looking a second time and more closely to this print my printer did the job very well. Using a smaller layer height it would even be better. Say 0.1 instead of 1.5 as I used now. Anyway I'm not going to. As I told before I'll use the same layer but a larger pitch instead. Measured value of this pitch I think it's about 0.8mm... correct...?

The idea making a Helix this way is very nifty indeed but imo a pitch this small is not practical at all while focusing. Lets assume working with a 1mm pitch. Turning the barrel say 1/8 of a revolution, you'll end up with a axial shift of only 0.125mm. Using a camera with a pitch this small would be perfect I agree. Using this focuser for visual observing, or even with little bit a coarser pitch, again, it is not practical, it is to slow. In the past I made rotating Helix focusers with a 3mm pitch and it worked very well. I'll try and redraw the two threaded parts with a coarser thread.

Can't print this thread, to small for my printers, pity... Even with a 0.3 nozzle. I'll try one more time lowering Extrusion Multiplier.

Finally found some free time to start testing this Helix. Sorry about the delay. I was very busy these last months. Before starting I have a question ; you added a 13mm long thread into the lower part of the casing. It is not needed at all imo, correct..?