His website says that he is still taking orders for the small and large chairs. He is not accepting orders for finished chairs, just unfinished. I've had one...
I have just ordered a 15"F5 PDHQ from discovery. Discovery - I think - places the secondary aprox 62.5" from the face of the primary. My question now is on the...
... I had a 17.5 inch dob that was optically excellent. Changing the secondary mirror to 3.1 inch from 3.5 inch clearly produced better sharpness on star...
The 15" f/4.5 Obsession, and the 14.5" f/4.3 Starmaster both use a 2.6" secondary mirror. I just got a 2.6" secondary for my 14" f/4.5 PDHQ (it has a 3.1"). I...
... use ... f/4.5 ... John: Let me know how this works out. I also would like to know how you like the optics. I just ordered the 15"pdhq. I haved moved into...
I have just ordered a 15" F5 PDHQ from discovery. In trying to decide on a 2.6 vs 3.1" minor axis secondary, I am struck by the fact that while discovery uses...
... Of course it is, A low profile focuser allows you to get away with an increaesed primary to secondary distance (equivalently, less distance from secondary...
... Of course it is, A low profile focuser allows you to get away with an increaesed primary to secondary distance (equivalently, less distance from secondary...
... actually ... f5 ... real ... NEWT. NEWT is a free design software available here. ... http://home.att.net/~dale.keller/atm/newtonians/newtsoft/newtsoft.htm...
... I already have the numbers crunched for off axis light fall-off with both a 2.6 and a 3.1", and my numbers concur with both the newt program and Mel...
I do appreciate the mechanical notes you provide, but what I am trying to find out is if the smaller secondary on the Obsession and Starmaster is facilitated ...
... Wow! I must be using very ambiguous language, I guess I should have majored in english instead of physics... Of course you cant do better than 100%. I am...
Wow! I must be using very ambiguous language, I guess I should have majored in english instead of physics... If you majored in physics why are you asking?...
Joe, I want to address this line by line also....so here is another post. Lets speak more precisely: Forget for the moment about tubes, low profile focusers,...
... - ... like ... secondaries ... To Big Dob Group: Please excuse any obnoxiousness on my part. I have perhaps been too long-winded, and therefore unclear. ...
Neil, I still think we are at cross purposes: In essence I think that you feel that I am oversimplifying. What I am trying to determine,is the comprimise...
Neil, I still think we are at cross purposes: In essence I think that you feel that I am oversimplifying. What I am trying to determine,is the comprimise...
Joe, The information you have requested regarding Obsession scopes is not commonly known, nor have I seen it published on any web site. Ditto for Starmaster,...
Joe Have you considered just calling the manufacturers and asking them? jtm ... From: "Joe Cannavo" <jpcannavo@...> To: <bigdob@yahoogroups.com> Sent:...
p.s. (I cant resist) saying that primary diameter x f ratio is a "more precise" equality to focal length is kind of (but not exactly) like saying that 5 x 15...
... In-depth questions and quest for answers ... That's what this forum is for ...right? ... Neil, Absolutly! My best bet might be to go with the 3.1 (21%...
I finally got the answere I needed from an obsession owner at sci.astro.amateur on google. As I suspectd, obsession uses as slightly shorter secondary to focal...
... With a given newtonian paraboloid, the size of the secondary and the position of its placement along the optical path (i.e. distance from primary), in a...
Hi group, I have been developing this Big Dob Finder/Travel scope combination and wanted to get some feed back from the folks who use large sized dobs. I have...
... you ... Thanks Nils: the .25" & .8" fields at focal plane agree with the .19 and .six-three (the numbers on this keyboard are messing up!)degree, fully ...
... you ... Thanks Nils: the .25" & .8" fields at focal plane agree with the .19 and .six-three (the numbers on this keyboard are messing up!)degree, fully ...
... you ... Thanks Nils: the .25" & .8" fields at focal plane agree with the .19 and .six-three (the numbers on this keyboard are messing up!)degree, fully ...
neil what's the name of the folder and is it in the files or photos area? tnx jtm ... From: "Neil Carroll" <ncarz@...> To: <bigdob@yahoogroups.com> ...
