Posts Made By: joseph cannavo

Looks great Glen!
Real nice workmanship!
Look forward to hearing how it does during moments/nights of good seeing. I'm on deck w/ a 16" Royce conical on order. I'm curious, how long did your order take? Also, I assume you have the blind hole as opposed to the full perforation (?)
Joe

I am starting to work on my truss assembly for a 16" F5 Royce conical. As an experiment for now, I am going to attempt a 2.6" ma secondary for a lunar/plnetary optimized scope. 1/4 degree at 100% illumination will be sufficient. (I do have a 3.1 I can switch two and a second Protostar assembly should I opt for a less vigneted field).
To achieve this, I will need a diagonal to focal plane distance of aprox 11.5". But my concern is this:
My Feathertouch has 2" of travel, and (I am working with an UTA of aprox 17" ID). Will I be able to position my focuser close enough to the diagonal to reach focus without throwing the focuser tube into the lightpath, thereby defeating the point of an aprox17% CO. Clearly this is eyepiece dependent. I will be using mostly Radians and Panoptics. Any hard numbers on where these EPs reach focus relative to the focal plane of the primary?Or, will I need less focuser travel to avoid obstructing the aperture ... In other words cam I pull this off?
Joe

Floyd , give this a try:
If you can get your scope bottom heavy enough, place small 0.5 pound ankle weights (or equivalent) on the truss rods roughly near the middle. I used this set-up on a 15" dob. The results are amazing. The weights create "nodes" that dampen vibration dramatically. Furthermore they also double as sliding counter-weights to fine tune balance. A more refined version of this approach is one of the design modifications (hacks? ...LOL)that I will be incorporating into the truss structure for my 16" Royce conical (which he just finished!). Like you, I am trying to go with some novel approaches, such as an eyepiece accessible collimation mechanism.
Joe

Spectacular!
There is a neat little "asterism" of six (?)craterlets located about one Plato width towards the lower left corner. Kind of arranged like a "Y" on its side:
:....

I never noticed this feature before, either visually or on any ccd images. Any guesses as to angular/linear(Km's that is) resolution in this image?
Joe

Bob
Also nailed Encke at both ends, nice image and processing!
Joe

Amazing
In all seriousness does anyone know of more detailed amateur image of Jupiter? If so post link!
I am measureing surface detail as small as 0.25" of arc! Ganymede looks like the visual appearence of mars through a small scope!
The only sad thing about such an image is that it seems almost unsurpassable...How much more resolution is possible?
Truly amazing!!
Joe

Stu
For a given scope contrast is a function of a variety of factors. Suffice to say, however, that a 10% (by diameter) central obstruction will introduce no visible loss of contrast. One issue, however, that you should be aware of:
In a planetary optimized scope, where ever last bit of diagonal is being used, be sure the diagonal has a good edge. If not all efforts towards such optimization are wasted.
Joe

Nice Bob, starting to catch Encke. Thoughts on larger image scale?
Joe

Scott I have heard both. FWIW, Bob Royce - I think - says "Streel"
Joe

YES!!
Protostar makes 3 vein spiders for up to - I think - 18"ID.
Joe