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Posts Made By: Brian Risley

November 5, 2003 03:19 AM Forum: Equipment Talk

Dust Covers

Posted By Brian Risley

I am looking for a dust cover (vinyl or hard) for my older C-8, but haven't been able to find anyone carrying anything that mentions fitting an 8" SCT. Years ago I know these were available, as well as eyepiece covers, as I still have the eyepiece covers. Meade carries some, but no one lists the actual dimensions it fits, I am looking for 9".

November 15, 2003 04:09 PM Forum: Equipment Talk

SCT Collimation Issues

Posted By Brian Risley

I was collimating my 1980 C-8 last night and have an issue with the image that I am trying to understand where the problem may be.
I get a good circle pattern inside and outside of focus except I also see a cone of distortion coming from the center to the bottom, almost like a parabola. If I shift to the other side of focus, a distortion appears on top of the image. Not the eyepeice, as I see this with different eyepieces and with and without the disgonal and it does not rotate with the eyepiece or my head rotation. Scope was outside for about 2 hours, so this is not thermal. Scope has not been used heavily for past 6-8 years, kept in its box.

Any ideas what I am seeing and where it may be coming from?
Is this something that will appear if the optical train is not perfectly centered, or am I dealing with some sort of flexure issue or optical problem?

(Getting this scope collimated cleanly and understanding what to do is a prep for my 1972 model being rebuilt/recoated completely.

November 18, 2003 03:14 AM Forum: Celestron

Older C-8 focus shift

Posted By Brian Risley

My 1980 C-8 (which had been sitting boxed up for about 6-8 years) had a real problem with focus shift. I removed the primary (I am quite familiar with disassembly, but it is not for the faint of heart!) and applied some fishing real lube to the focus tube shaft where the mirror holder is normally positioned and spread it around evenly. (Shaft/focus bearing assembly had plenty of lube, so I didn't add any.) I checked the assembly first and could find no hint of any lubrication in this area before I added some. After reassembly, there is very little shift. (500x during collimation would sometimes shift the image out of the view, now it stays almost exactly in place!)
Time will tell if this is a good lube to use, unless someone else knows of something better, it really fixed things up for me!
If you are experiencing big shifts, then this is a definite area that may need to be checked. Some people mention releasing the bearing and moving the assembly around in the tube, but I found no lube to be present, so this may not work! This makes my collimation and planetary observing much easier. Weather hasn't cooperated for me to do final collimation steps on a planet, been too unstable here in SW FLA.

November 28, 2003 03:33 PM Forum: Equipment Talk

Homemade C-8 Tripods

Posted By Brian Risley

Looking for plans for a homemade tripod (wood preferred) that will support a standard Celestron wedge for the older C-8's.
I remember seeing some in the mags many years ago. Want to build one for my second C-8.


December 3, 2003 06:21 AM Forum: CCD Imaging and Processing/Solar System

Vesta Magnification

Posted By Brian Risley

Trying to get a grasp on the apparent magnification that a Vesta 675 will give with a mogg adapter on a C-8.
What factor should I use for calculating against the FL of the scope?

January 5, 2004 04:54 AM Forum: Equipment Talk

Meade Microfocuser

Posted By Brian Risley

Does anyone know what the control signals to the meade microfocuser are? Is it simply a DC voltage, or is it some sort of stepper controller?

I am looking for a fine focus for my older c-8, and can get one without a separate controller, but if control circuit is simple, I can build one.
Thanks for any info.

February 28, 2004 05:39 AM Forum: CCD Imaging and Processing/Solar System

k3ccdtools Darkframe

Posted By Brian Risley

I have been trying to get a darkframe merged with a video capture, but each time I get a message about the darkframe being a different resolution than the video.
I have even tried the m57_divx and dark_divx examples on the tutorial page. I cannot get it to load. Can anyone possibly tell me what is going on and how to get around this?


April 2, 2004 03:25 AM Forum: Solar System Observing

Solar Film Material

Posted By Brian Risley

Has anyone compared the Baader film to the Thousand Oaks Black Polymer? Costs are about the same. I am curious as to the image differences (other than color). My understansing is the the black polymer is more durable than the Baader, which from all my reading, seems to be pretty sensitive to accidental touches.

Thanks for any info,

May 6, 2004 03:16 PM Forum: Solar System Observing

New Message Group

Posted By Brian Risley

New message group for current events such as comets/transit/eclipses etc.

Brian Risley

May 16, 2004 06:30 AM Forum: Eyepieces

Rini Eyepiece Ad 271633 - Mortar Shell

Posted By Brian Risley

If the Naglers and like are hand grenades, this thing is the mortar shell of eyepieces! That 2" diagonal looks puny next to it. And he only wants $55? That thing is probably larger than my c-90!