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Posts Made By: James Adams

July 12, 2004 01:20 AM Forum: Equipment Talk

Help With Collimating a Classical Cassegrain

Posted By James Adams
Larry,

Someone told me that IF you can remove the focuser tube you can simply center the diffraction rings out-of-focus, and be right on.

I may be wrong about this, it's been awhile; try contacting Joe Nastasi at Parallax Instruments. He could tell you the procedure.

I hope I'm not volunteering him inappropriately.

James Adams

August 16, 2004 11:18 PM Forum: A Day in the Life of the Administrator

A pleasure

Posted By James Adams
Phil needs to bump up his meds, apparently.

James Adams

August 26, 2004 07:08 AM Forum: Telescope Making

Aluminum tube - "Au Naturel" ?

Posted By James Adams
Mike,

You can alodine your tube yourself, cheap, with chemicals available at your local auto paint supply store; the resulting finish is a smooth, warm grey which is nicely paintable.

Alodine is a conversion phosphate process which creates a smooth oxide finish which is highly weather and wear resistant. Do a search, there are several suppliers for the chemicals, and it's an easy process.

James Adams

August 26, 2004 02:09 PM Forum: Telescope Making

Modifying a refractor

Posted By James Adams
Rob,

I've shortened a couple of refractors myself so as to use a binoviewer without having to Barlow it. I did it on my tablesaw, but I don't recommend the process.

You may have to move or remove a baffle at the EP end, and you may not have enough backfocus for some configurations without using an extension tube, but in my case it's worked fine!

James Adams

September 10, 2004 02:18 AM Forum: Equipment Talk

Which would you pick ?

Posted By James Adams
I've looked through two AP 7" refractors, and they were awesome; but the price still seems a bit high to me. I suppose it would depend on your usual viewing conditions, mount, and [your]physical condition, as usual.

If you have excellent seeing frequently, either scope should suffice. If not, why waste your money? Do you image, or are you primarily visual? Are you well off enough to really consider purchasing either of these scopes? Do you spend enough hours at the eyepiece? Can I come over to your place to gather photons?

James Adams

November 16, 2004 05:10 PM Forum: Refractors

Antares 105mm long focus

Posted By James Adams
I replaced my Celestron Firstscope 80 lens with the Antares Research Grade objective, then did the same with a homemade 4" f 15. In both cases the improvement was stunning.

The 4" gave outstanding views of Mars last year and has become my favorite scope for planetary viewing [until I can afford an apo and to finish some other scope projects.]

James Adams

February 9, 2005 11:50 AM Forum: Refractors

Hong Kong 8.5" lens, any reviews?

Posted By James Adams
Bill,

Yes, I have one of these, which will eventually get folded and paired with a Chromacor [I hope]. It is in a temporary tube at this time. I tested mine at Chabot Space Science Center's telescope making class. It tested very nicely. In practice it needs an aperture mask to 7.75" because of a slight turned edge. I put the focuser, a 2.5" D&G, in a sliding section in order to use a binoviewer without a Barlow.

You will need a BIG mount; I use a homemade GEM similar to OpticCraft's, with 3" shafts, and it needs to be about 6' high, minimum.

I can't speak to the spec's you've been given. Have to take someone's word for those; my lens is coated, and shows no ghosting, but it doesn't seem a very noticeable coating. I paid about 2K for mine, three years ago.

Cooldown is an issue. It's a HEAVY piece of glass! but once that's done, WOW! Size matters!

February 9, 2005 03:17 PM Forum: Refractors

Hong Kong 8.5" lens, any reviews?

Posted By James Adams
The reason why these aren't sold on AM [it is my understanding] is that the exporter can't get an account. I purchased mine through AstroBuffet, paying a bit more for someone else to take the risks.

J.A.

April 11, 2005 11:21 PM Forum: Equipment Talk

fork mounted 9" refractor

Posted By James Adams
John,

I built a GEM for an 8.5" f 12.5 refractor out of 3/4" alu plate with 3" pillowblock bearings. I'm saving up for drives / gears, which alone will cost maybe $ 2K. The GEM on homemade pier is over 6' high and I still need to lie on the ground to view near zenith.

This really needs to be a folded setup. I have a flat mirror, which was very expensive, 6" diameter 1/15 wave PTV of which only the central 5" will be used.

Unless you wish to use low power for wide field views exclusively, you will want a motorized drive. You can do this, should you fold it, like a Dob, with a motorized platform. This is likely the most economical solution despite the expense and difficulty of obtaining a large, high quality secondary.

James Adams

May 31, 2005 01:28 AM Forum: DVDs and Music and Books That You Recommend

Your Favorite Fiction---Top Five!

Posted By James Adams
Top five: Roger Zelazny, " Lord of Light", Orson Scott Card, "Ender's Game" and "Speaker for the Dead", Sean McMullen, "Souls in the Great Machine", "The Miocene Arrow". All science fiction, all adult and well conceived.

James Adams

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