Lee, Here is an alternate idea you might find interesting. I have a 13.1" F4.5 truss dob that I built with two focusers. The main one is for normal eyepiece...
Neal, Without designing in the need for a shorter tube, the FOV would be too small for my tastes. I don't want to bring the focal ratio below 4.5. A 16 f4.5 ...
The recently released Hubble Pics (4/30/2002)include a picture of NGC4676 (The Mice) in the region of the Virgo Galaxy cluster (or nearby Coma Berenices)....
In southeastern Virginia? Forget it! I live in Virginia Beach, and the skyglow is horrible! You have to drive an hour or two to get to a reasonably dark site. ...
design the mirror cell to have an adjustment allowing it to slide forward 5" this can be done at least two ways. however the one way will change the balence...
Hi Randy , In a 15-16 inch scope you can expect to detail in brighter galaxies . Fainter galaxies to about 13.5m look like "faint fuzzies" . Hope that helps . ...
ive hit 14th magnitude with my 10" dob however it did take dark skies AND altitude. my 16" dob hits magnitude 14.9 on a regular basis and has, on one occasion,...
John, I was thinking about making the secondary cage adjustable. If I'm lucky enough, or if I plan correctly, the contraction of the secondary cage for ...
Randy, From my driveway (no problems with neighborhood lights, limiting naked eye magnitude usually ~5.3), I find that my 10" is good to about mag 12 and my ...
here is yet another idea. make your secondary cage 8 sided. on 4 sides have the regular truss hook ups and on the other 4 sides have them 5 inches futher up on...
... the ... Good Idea. How about 2 upper cages? One short, one tall. I like the idea mentioned earlier about having 2 focusers on one cage and a "second"...
Two upper cages mean two secondaries. I don't have a binoviewer yet. It is on my wish list. I have used the TV binoviewer for planetary viewing on a 5" AP...
... the TV ... amazed with ... That is agood indicator. I use a TV binoviewer in 12.5 and 16" scopes. My use with the 2x barlow attachment works very well for ...
Hi, An idea I thought of was to have a straight tube at the end of each truss. the trusses would be shorter than usual, and the upper box would slide higher or...
... I also wanted to add that your secondary would need to be slightly larger to accomodate the closer setup for the binoviewers, but is probably worth it. WB....
I picked up my dob this weekend and got it home. Damn its big! One issue I have to correct is the fact that a 31mm nagler t5 can not achieve focus. I have...
I don't know if that is a typo or if it is an old (or very new) model that I'm not familiar with. I have a 10" Meade *Starfinder* with the same specs. I was...
That is a very fast mirror for a 25" dob and precise collimation will be critical. I would go to the trouble to have the poles uniformly cut at a machine...
David, Tha Kriege/Berry book on building a big dob indicates that you should use a tube cutter, available from plumbing suppliers, to cut the tubing. Jonathan...
Hi group, Long time since I did not participate! ... Don't forget that with an f/4, the 31 mm will give you an exit pupil of 7.75 mm which is likely larger...
Hugues.Laroche@...
May 6, 2002 2:23 pm
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as long as you're cutting consider that with a 42mm fieldstop and an f/4 scope you might want a paracorr to minimize coma. this also requires some additional...
Get a pipe cutter at Lowes/Home Depot. Make sure you are getting one that will handle the outside diameter of your tubes. If they are 1.5-inch tubes, you're...
David: Before cutting your tubes, you may want to experiment with raising the primary mirror height by screwing in all three collimation bolts. I had the same...
I do have and use a paracorr. Is there some math I can do to figure out how much to cut the poles? David ... an f/4 ... requires some ... like ... but ... ...
Its a custom Dob built by Joe Castoro. I bought it used. Some very interesting well know people worked on this scope. It has an interesting history. Back...
Thanks for all the advice! I will have to do some research so I can figure out how much I need to trim the poles. I will try cranking in the mirror a bit to...
Thanks for all the advice! I will have to do some research so I can figure out how much I need to trim the poles. I will try cranking in the mirror a bit to...
