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Posts Made By: Stephen Sherrod

January 13, 2004 03:49 PM Forum: Telescope Making

Cell mount : Aluminum vs.steel?

Posted By Stephen Sherrod
Aluminum is better than steel for thermal reasons. But, for a 12.5" at full thickness, something more than 3-point suspension might better keep your mirror from distortion (= astigmatism).

January 17, 2004 12:56 AM Forum: Telescope Making

Velvet Flocking

Posted By Stephen Sherrod
Flocking is a good start. There are many other "contrast
enhancements" that can be done too; I listed 10 or 12 several months ago in a similar thread.

I noticed in the photo that the spider washers and the focuser and finder nuts/bolts are quite shiney. I use a small water-color brush and paint all that stuff with flat black Rusteoleum sprayed on a paper plate. It dries fast so it usually takes several sprays on the plate. I even reach around "back" and paint the shineys all around 360 degrees. Just a bit more to help reduce more reflections/scatter.

January 27, 2004 04:49 PM Forum: Telescope Making

Source for premium 8" mirrors (RF Royce?)

Posted By Stephen Sherrod
Don't forget Mike Spooner's mirrors. Ask around about them or just do a search here on the forums. I don't think you can get a better mirror.

March 16, 2004 04:29 PM Forum: Equipment Talk

Interesting Astromart Binocular Ad...

Posted By Stephen Sherrod
Probably just that the 12x60's have a smaller TFOV and that the increased image scale (~71%) would be a big difference and increase the apparent seperation by the same amount. I believe the "brighter" realy means "just as bright" since most people never get their eyes past 5mm exit pupil, even when we think we are "dark adapted". The image scale was probably the impresso-factor.

S.S.

March 23, 2004 12:07 AM Forum: Telescope Making

Dob Alt Bearings

Posted By Stephen Sherrod
Wouldn't it be better just to use some nice-looking weights and balance the tube? Scopestuff sells them for just that purpose.

S.S.

March 30, 2004 08:54 PM Forum: Telescope Making

university optics mirrors

Posted By Stephen Sherrod
They are made by, and identical to, Discovery mirrors.

S.S.

June 2, 2004 09:20 PM Forum: Telescope Making

Changing mirrors.....need help

Posted By Stephen Sherrod
I called Royce recently about a possible refigure on a mirror I was thinking of buying and (1) he said he didn't do "refigures" and (2) wouldn't work with anything not Pyrex, or the fancier substrates. Certainly not Soda-Lime or BK-7.

Also, just curious, why would you want a Chinese scope around an eventually expensive mirror? Why not just go for a premium scope in the first place?

Steve S.

June 12, 2004 11:09 PM Forum: Telescope Making

Secondary mirror

Posted By Stephen Sherrod
http://www.fpi-protostar.com/images1/afm1.gif

June 18, 2004 02:54 PM Forum: Equipment Talk

University Optics mirrors

Posted By Stephen Sherrod
Right; if it performs well, then why replace?

But, to answer your question, the UO mirrors are made by, and identical to, Discovery.

October 15, 2004 11:38 PM Forum: Equipment Talk

Re: Sidewalk Test

Posted By Stephen Sherrod
I know it is just a photo on the internet, but if this thing, and subject, is correct the Nagler and UWA look like expensive, small mirrors; real bad. I think the UO looks better than the Nagler in this photo, and the Parks is a disaster.

Wasn't there a topic recently on "Nagler vs Pentax"? If so, maybe something like this might help on that decision for prospective buyers. I was looking toward the Pentax anyway, long before today, based on the recommendations of another optician that you all probably already know and love... smile But, I would hate to be the first guy in 8 months to post anything other than plans to buy every eyepiece ever made by TeleVue! 8)

S. Sherrod

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