Dear All, I have a 16" F5.5 Dob on a tracking platform in a roll-off roof observatory ( that I use primarily for lunar imaging ). Wind at my site is becoming...
David, My experience is a dome will only protect you from the wind when the slit is more-or-less pointed downwind. This works fine if you are not after a...
Elliott... what I did worked out well and is easy to do... I obtained a length of 3/4" x 3/4" aluminum angle stock (1/8" thick) and cut 2 pieces one for each...
Hi Paul, Yes, I have become quite good at ladder repositioning to make things more comfy. Often one can fiddle with the position until something good works...
Les I've been considering a 22" dob myself. May I ask what who made your new scope? Thanks John Stewart ... from my portable 18", one of the main motivating...
Elliot, ... Take a look at the solution I use on a 25" f/5 scope. It's a very simple wooden half-step that can be put on any of the normal steps of the ladder:...
Hi John, Well, I didn't make it -- the decision not to make was mainly motivated by my back issues. If I had proceeded, I would have went down exactly the same...
Robert wrote; Take a look at the solution I use on a 25" f/5 scope. It's a very simple wooden half-step that can be put on any of the normal steps of the ...
If you could afford that dome, you could affort a 16" LX200, which would fit in a much smaller dome and be much easier to image with. You'd have to measure the...
Hi Paul, ... Why? Is ... No, that just happens when you use scrap pieces of wood... ... pushed ... made ... Exact. ... step, ... up ... photo, ... No, there's...
Thanks, Robert, building one of these guys is at the top of my to-do list. \Paul A -- "Robert Houdart" <robert.houdart@...> wrote: Hi Paul, ... Why? Is ...
I use a similar 3/4" plywood step but it is the full width of the inside of the ladder. It is attached to vertical pieces of plywood at each end that are...
I was wondering how much collimation accuracy would affect our computers accuracy, in determining positions for objects? Would it be a couple of arc minutes,...
Hi Kyle I must be one of the laziest people when it comes to collimating - I just drop the lazer in and do it by eye from the primary once I get the dot in the...
Minor errors in collimation are not too significant. The diffraction limited field in an f/5 Newt is a couple mm wide. For a typical big dob the image scale...
... limited ... image ... to ... Thanks John, for your very thorough analysis. That's about the right amount of accuracy increase, that I've noticed with my...
I am using a 12.5 Dob with an astro video camera. I am finding that an in ordinate amount of time is being spent making slight adjustments in the field of...
Electric motor drives with rubber wheels against large plywood disk edges is one way. Chuck Shaw used alt-azimuth electric drives very nicely on a 16 inch...
With a clean slate, if you wanted to optimize the design for the smallest possible secondary, what would be the basic optical element specs, say with a 32"...
Figuring a convex mirror usually means grinding and polishing three surfaces (concave test plate, matching convex mirror, and back of same) and figuring two...
If the modern "Partial Offset Collimation Protocol" is followed, wherein the secondary is centered under the focuser (typically using a sight tube), but not...
... Not quite right. For "simple" DSCs (those that don't compensate for mount errors), the optical axis should be perpendicular to the alt axis, and the alt ...
Thanks, Greg. Knowing it has been done helps. I am optimizing several things that will help. Weight and balance, as you mentioned is important but is pretty...
John, Not quite. If the optical axis is offset in pure azimuth (focuser exactly on the side), the two axes of scope movement are still perpendicular. One ...
Roland, I ran into the same problem when I wanted to be able to track at very high powers. Stickiness ("stiction") in the axes made exact pointing difficult. ...
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