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VdB 141 Ghost Nebula

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Posts Made By: Philip Sawyer

May 14, 2004 06:54 PM Forum: Telescope Making

Off Axis fantasy

Posted By Philip Sawyer
I wonder if anyone has tried to build a reflecting scope similar to the one featured in the March 2004 S&T. The featured one is a 6 inch reflector that folds the light back toward the primary thus allowing the observer to place the eyepiece near the primary rather than at the top of the tube. It seems to me that this configuration would allow for considerably longer focal lengths; but would the law of diminishing returns come into play (light dims with the square of the distance from the source) therefore 2x the distance in the optic path would diminish the light by a factor of four? As you can tell I am searching for a reason to avoid making this fantasy a reality. My dream calls for a 8inch spherical mirror with a focal length of 17 feet. Folding the light would place the secondary at about eight feet. In addition with a focal length that long there would be no need to aspherize the primary. Any comments? Be kind please.

May 18, 2004 04:12 PM Forum: Telescope Making

Celestron Reflector

Posted By Philip Sawyer
Anyone have any experience with observing the sun through a 6 inch celestron refractor? I am interested in advice about the best solar filter:Glass, poly, H-A and who might make such a filter?
Thanks for all your input

May 18, 2004 04:39 PM Forum: Equipment Talk

Celestron Refractor Solar filter

Posted By Philip Sawyer
Can anyone provide some advice on when to get a solar filter for a 6 inch refractor?

May 24, 2004 05:50 PM Forum: Equipment Talk

Cleaning Orion 10 inch dob mirror

Posted By Philip Sawyer
I tried to clean my 10 inch dob over the weekend with a swifter attached to a painting pole. It gathered much of the dust that had settled on the mirror but there were some other form of unwelcome spots that just smeared when the duster passed over them. I wonder if any of you good folks have any info on how to remove the mirror from the tube? There are phillips head screws in the base that go through the tube do these ned to be removed to release the mirror cell?
Thanks for all your kind advice

June 4, 2004 04:46 PM Forum: Equipment Talk

Knobs

Posted By Philip Sawyer
Good day gentelmen! (Ladies too!)
I recently purchased a 6" Celestron refractor and I am looking for the "cable knobs" for slow motion slewing. It is difficult to look in the eyepiece and reach the knobs unless they are attached to those really cool cables or you have the arms as long as a chimp! Is there anyone out there that can tell me where I can purchase these seemingly rare attachments?


June 13, 2004 07:28 PM Forum: Telescope Making

8 inch newt

Posted By Philip Sawyer
Good day all! I started grinding my first 8 inch newt today using a kit from William Bell. I started with the 60 grit as instructed and have put four hrs into the project. Instead of using the supplied glass tool I opted for a two inch pipe cap tool. Can anyone suggest when I should change grit to the 80 stuff? Should I wait to change after I have my full curve ground or should I change to 80 grit at some point before I reach the desired saggita? How can I tell when to go to the next grit?? :S (F/L approx 1700mm so I calculate saggita approx 1.5mm. Any advise would be greatly appreciated.

June 24, 2004 04:45 PM Forum: Telescope Making

Supercharging A Dob

Posted By Philip Sawyer
I wonder if any of you gentlemen (or Ladies) have ever tried to make a convex reflecting lens to replace the normal diagonal in a Newtonian so that the resulting reflected image is 150% - 200% of the normal image? I realize that this would entail positioning a diagonal lower in the light path to reflect the image outside the tube. Anyone ever try this? I would like to hear your thoughts.


July 13, 2004 07:47 PM Forum: Equipment Talk

Collimating 10 in. Dob

Posted By Philip Sawyer
Good Afternoon everyone:
Well I made my first attempt at collimating my 10 inch dob over the weekend. What a disaster! I moved the diagonal, I moved the primary; Heck I moved everything! But try as I may I couldn't get the laser spot in the center of the primary and still have the returning spot line up with the hole in the eyepiece. Is this process as hard as it seems or am I doing something wrong? Here is the question: Should I be able to get the laser spot in the center of the primary and at the same time have the return beam plumb in the center of the eyepiece hole. I can get the spot in the center of the primary but then it isn't in the center of the eyepiece hole and when I have it centered in the eyepiece hole the spot on the primary is only halfway to the center of the mirror (one third from edge) Any advice will be graciously accepted!

June 13, 2005 04:32 PM Forum: Reflectors

Focusers

Posted By Philip Sawyer
Good day everyone:
I am toying with the idea of replacing my factory focuser (Orion 10 reflector) with a Moonlight with a "fine" focus adjustment. I wondered if there were any sky watchers that have tried this upgrade and if I am in for lots of fine adjusting to get the combination to work. Specifically I wonder if I have to be super precise in getting the new focuser seated against the tube so I get a straight through (square) reflection?

July 21, 2005 08:35 PM Forum: Telescope Making

Diagonal

Posted By Philip Sawyer
I wondered if any of you fine astronomers have ever swapped the standard diagonal that comes with the Orion 10 inch reflectors for a smaller diagnoal. Perhaps, if you have, you can share your results, details and supply source of the replacement mirror?

Best Skies to you all and thanks for any info.

Philip

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