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VdB 141 Ghost Nebula

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Posts Made By: Roland Christen

November 9, 2007 04:52 PM Forum: Equipment Talk

oil for Byers gear?

Posted By Roland Christen
Add some light lithium grease to the teeth. Clean out any dirt before you run the gears.

Rolando

November 9, 2007 04:57 PM Forum: Astro Binoculars

Celestron 11 X 80 Comet Hunters

Posted By Roland Christen
I have a pair of these binocs. They are of average quality, fairly light in weight for their size. Good light grasp on axis, light falloff toward the field edge due to severe internal vignetting. Stars become severely distorted toward the outer 40% of the field. Not in the same league as more premium brands for edge sharpness.

Rolando

November 9, 2007 10:42 PM Forum: Refractors

Why is lead "faster"?

Posted By Roland Christen
There is no lead in ED glass. There may be lead oxide in some flint glasses, but there are plenty of candidates for a mating element that have no lead oxide in them. Lead doesn't make a lens "faster". The Vixen ED doublet was not some sort of special design using "unobtainium". It was a very basic ED doublet with ordinary glasses.

Rolando

November 19, 2007 07:48 PM Forum: CCD Imaging and Processing/Deep Sky

NGC 2403 - Close in

Posted By Roland Christen
You certainly know how to get the most out of that 8" Celestron SCT.

Rolando

November 20, 2007 11:37 PM Forum: Bad to the Bone Autos

So, why can't Detroit do this?

Posted By Roland Christen
Here's more on biofuel powered hot rods: http://www.hlineconversion.com/tv-media.php#readmore

November 26, 2007 04:25 PM Forum: Refractors

APO doublet vs triplet question

Posted By Roland Christen
A doublet relies on the fact that your eyes selectively filters out the deep red and deep blue-violet wavelengths. Even though these colors are unfocused, they appear only faintly to your eyes, or not at all. Some eyes will see these defects better then others. Older eyes filter out the violet better than young eyes.

In an integrated time exposure the color error will appear as a violet halo. That is mainly why triplets are favored as imaging scopes over doublets, because they bring more of the violet spectrum into critical focus with the result that stars appear tighter with minimal or no blue-violet halos.

Rolando

November 28, 2007 04:32 PM Forum: CCD Imaging and Processing/Deep Sky

IC405-410 area

Posted By Roland Christen
Good shot, Gilles wink

Rolando

December 7, 2007 05:31 PM Forum: Equipment Talk

Televue NP127is or Takahashi TOA-130?

Posted By Roland Christen
If you are into imaging, the Televue IS model is quite nice. Check out this image taken by master astrophotographer Tony Hallas with a mere 4" Televue IS model:
http://www.astrophoto.com/M45WF.htm

Rolando

December 13, 2007 07:46 PM Forum: Astro-Physics

Pictures from down under

Posted By Roland Christen
Santa's village

December 14, 2007 06:51 PM Forum: Refractors

Tom Back????!

Posted By Roland Christen
>>I only hope that TMB Optical is not over, and continues producing great equipment.>>

Tom Back was a designer, he never produced any telescopes. Scopes were produced for him by APM and the lenses were made by Lzos in Russia. These scopes are still being made and sold today, by APM directly and through Teton Telescopes.

Rolando

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