Posts Made By: William Earl

I was wondering if anyone knew the difference between the "Custom" and "Custom D" mounts. Photos would be great. Thanks,

Bill

Hi,

Has anybody heard anything lately about the proposed TMB triplet semi-apo to replace the lens sets with the original 1026 scopes? I called BO the other day and left a message but have not received a return call. I don't belong to the Yahoo groups so I was wondering if somebody might share any news they have heard. Thanks and clear skies.

Bill

I saw this on our feeder today. North central Texas.

Hey everybody,

Hope all of your astro viewing has been enjoyable. Has anybody received their fine focus knob from Burgess yet? I "put my order in" (I opted for the ugly version - supposedly without a wait) to his wife a couple/few weeks ago and thought it would arrive by now. She was also going to send me a new chrome draw tube for my 2" diagonal which has become stripped. Man those threads are fine! Just checking to see if I need to get back on the phone. Thanks, and clear skies,

Bill Earl

Well,

Got the final word from BO that no additional "promised extras" will be made available for the 1026's. I received the 2" diagonal some time ago. Gave up on any objective replacement options way long ago. I was hanging on to hope for a microfocuser though. Wanted to get that installed before getting it ready for sale.

Even though it was a great deal overall, I still think BO should have come through with their promise. I bought the scope "as is" with respect to the lens, but was told it would be outfitted with the originally promised accessories. BO cited that only 50 scopes were sold (out of 200 manufactured - others returned to China) so not enough to justify cost. Strange logic to me.

Well, time to modify it so binoviewer can be used with 2" diagonal. Will require cutting tube by ~2" and drawtube of focuser by ~3". Also plan to adjust internal baffels (removed step down baffle when I got the scope) so both function properly at full aperture. Probably will flock as well. Made a couple aperture masks (62mm & 72mm) which greatly improve the planetary/lunar performance. Also drilled holes in the focuser knobs to create "spokes", and converted finder scope to 90 degree. Looks better.

When the final changes are done it will be a decent low power binoviewer capable scope with modest planetary/lunar capability. At that point I won't mind selling it "as is".

Clear skies,

Bill

Trey, back when I had aspirations of getting into astrophotography (Imay still get into it someday) after getting my ST80 reality convinced me that I was going to have to spend a lot more $ and develop infinitely more patience. Anyway, I experimented with the "problem" and discussed it with the tech guys at Orion. They told me that at f5 the scope just could not do epp. Photo work in general required using a tube extension. They sell what looks like a barlow w/o any lenses for ~$25. I bought one along with thier universal camera adapter and t-ring (I have an old OM-1) and was able to do epp with the 25mm Kellner that came with the scope. The 10mm Kellner just made too small of a light cone to be practical in use. Although, even with the 25mm astro work was nearly impossible do to the lack of light in which to focus with. The moon and daytime photo work were about all I could shoot. A big problem was that with all those attached the scope was severely out of balance w/r to the 1/4"-20 thread post. I eventually bought a set of 90mm tube rings and that took care of it. The cool bonus that nobody thought of was that when the tube extension is in place, there is a certain range of focus (can't remember exactly) where the scope acts as a macro lense. I took quite a few shots of different insects. From about 2 feet away (far enough not spook them) you could fill the field of view with the face of a grasshopper. Keep at it.

Thansk Ed. The reason I'm asking is that I just finished building a "slitless" tester using directions from the Stellefane website. They didn't provide directions for its use but it is set up such that the light source and the knife edge move together. So far I've only used it with a Ronchi grating, and it works well with that. The strange thing is that when the light source and knife edge are stationary, I can move my eye forward and backward from behing the viewing window and see the text book shadow patterns vary on the surface of the mirror. Do you or anybody else know of a good reference book that explains the use of the slitless configuration. I have only read about the classic tester that has a stationary light source and a moving knife edge. I'm about ready to build another tester.

Dave,

Just out of curiosity... Which scope provided a better view of Saturn? Thanks and clear skies.

Bill

Walter,

I am by no means an expert. I made a 10" under the tutelage of John Dobson last year and am trying to finish a 16" thin plain glass mirror this year. Mark Harry has been offering me some advice on this forum. I didn't get the chance to learn much about figuring from John because he all about star testing exclusively and no disrespect to him, but he doesnt explain things too well. Any way, that mirror works great and it was ground from scratch, etc...

The 16" however, I had pre-generated because the thought of hogging out something that big didn't appeal to me. Besides, I think the pre-generation only cost ~$20. With the coarse grinding out of the way, fine grinding was a breaze. I built a 2" thick, 12" plaster tool and its weight did most of the work. I built another 2" thick, 12" tool for a pitch lap and that was a whole different story. Man, that thing liked to grip the mirror. Sometimes I didn't think I had enough strengh to pull it across the thing. Especially in the early going. So if you are breaking a sweat now, get ready to sweat a little more.

Anyway, if I can make one suggestion, it would be to replace the carpet before polishing. I used a plywood top on a barrel and it worked very well thru fine grinding and polishing. I took a couple month break and when I returned, the barrel lid had warped a little and carpet had certainly flattened some. I ended up getting astigmatism after some figuring. I cut another piece of carpet and added it to the first and was able to remove the astigmatism.

Best of luck with the project. Your photos are inspiring. If I have learned one thing about mirror making it is that it is best done with support from others. I don't know what I would do without this forum to read every day.

Clear skies.

Bill

Nathan,

Someone once told me that it can make a differnenc if you plan to use an off-axis aperture mask at some time. The best place to position the "hole" is at the bottom of the mirror since the thermal plumes of warm air rise vertically upward. Good luck and clear skies.

Bill