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Posts Made By: Roy Troxel

August 15, 2007 06:36 PM Forum: Reflectors

Resolution: Reflectors vs. Refractors

Posted By Roy Troxel

smileThis is probably old stuff to some of you, but after being into this hobby for the past year, I have come to the following conclusions:

1. Reflectors can have as high a resolution as refractors of the same aperture.

2. Refractors have better contrast, making it easier to see details on planets or galaxies. However, contrast is not the same thing as resolution.

3. Reflectors can have as good resolution as refractors, but you might have to strain your eyes a little more with the reflectors.

4. Reflectors that have been properly collimated (assuming the mirror has, say, one-tenth wave correction) can actually have the same resolving power as a refractor of the same aperture.

5. In order to be properly collimated, first both mirrors must be collimated by laser, then they must be star-collimated.

6. Star-collimation: Focus a star with your highest magnification eyepiece. Next, gradually take the star out of focus. The star's image should then display Airy rings, which should be concentric. If they are not, then you need to collimate your mirrors until they do.

OK, now if someone can tell me where I'm wrong or right, that would be great! smile

September 3, 2007 04:23 PM Forum: Reflectors

StarSplitter Telescopes

Posted By Roy Troxel

I've been trying to find more information about these scopes, but I can't seem to locate any reviews.

The Astromart forum writers speak highly of them, but don't get down to any specifics. One of the posts said the company might be out of business, but I notice their web site is still up. Here's the link:

September 30, 2007 01:17 PM Forum: Eyepieces

New to 2" eyepieces

Posted By Roy Troxel

I've recently put the down payment on a new scope (12.5" Obsession) but I know nothing about 2-inch eyepieces. I was advised at a star party to begin with the "TeleVue 220", but I'm not sure what that is. Is it a 2-inch eyepiece with a 20mm focal length?

Thanks in advance...

April 14, 2008 06:51 PM Forum: Deep Sky Observing

Southwest Observing Locations and Astronomy Clubs

Posted By Roy Troxel

Having just returned from a month's vacation in the Southwest, I'd like to share some information in regard
to various dark-sky parks and local astronomy clubs.

The state parks each have a small office, showers, electricity outlets, etc. They are also regularly patrolled by park rangers. I recommend setting up your scope in the areas designated “primitive”, because they have the least light pollution from nearby cars or RVs.


Gary Myers
c/o StellarCAT
Sierra Vista, AZ
[email protected]

As some of you know, Gary is the maker of the ServoCAT drive for Dobson scopes. He also has several acres of land available for observing. On an average night, you can see down to the 7th magnitude, near the zenith. Minor light domes from nearby Sierra Vista.

Huachuca Astronomy Club

P.O. Box 922
Sierra Vista, AZ 85636
Contact: Ms. Jeanne Herbert
(520) 366-5690

(Sierra Vista is about 70 miles south of Tucson.)

Tucson Amateur Astronomy Assoc.

P.O. Box 41254
Tucson, Arizona 85717
[email protected]
or Liz and John Kalas at 520-620-6502

Organ Pipe Cactus National Monument

10 Organ Pipe Drive
Ajo, AZ 85321
Barringer Meteor Crater

Physical Address:
Interstate 40, Exit 233
Winslow, AZ 86047 USA

Mailing Address:
Meteor Crater Enterprises, Inc.
P.O. Box 30940
Flagstaff, AZ 86003-0940 USA
[email protected]

New Mexico:

City of Rocks State Park

P.O. Box 50
Faywood, NM 88034

Park Manager, Ken Abalos
(575) 536-2800
[email protected]

Villanueva State Park

PO Box 40
Villanueva, NM 87583

Park Manager, Frank Gutierrez
(575) 421-2957
[email protected]

The Albuquerque Astronomical Society

PO Box 50581,
Albuquerque,NM 87181-0581
Contact: Melissa Kirk
Phone: 505.254.8227
Email: [email protected]

Datil Well Campground

(I didn’t visit this one, but was told by several people that it has the darkest skies in New Mexico.)

Socorro Field Office
Bureau of Land Management
901 S. Highway 85
Socorro, NM 87801-4168

(575) 835-0412
(575) 835-0223 FAX

Southern California:

Anza-Borrego Desert State Park
San Diego County, California

[email protected]

(I stayed in the area called Little Blair Valley.)

Roy Troxel,
Harford County Astronomical Society

October 4, 2008 01:40 PM Forum: Equipment Talk

Telrad displays double image

Posted By Roy Troxel

This week, my Telrad got jostled around in the trunk of my car. Now it displays a double overlapping target image. This double image is smaller than the original single image. I've taken the device apart and consulted the schematics, and everything looks in place - the lens, the LED, etc..

Any ideas regarding how to fix this would be appreciated.

Thanks in advance,


September 6, 2011 06:32 PM Forum: Equipment Talk

Transporting an assembled large dob

Posted By Roy Troxel

At the risk of sounding clueless...

Over the last few years, I've noticed people traveling with their large dobsonians, completely assembled, in a trailer or panel truck. It seems to me that would be a dangerous practice. Even if you had the entire assembly tied down, wouldn't the mirror slide back and forth, hitting the inside of the mirror box? Or wouldn't constant vibrating shake loose some parts, like the secondary mirror? Or worse still, suppose a rope came loose, and your 16" dob began sliding around and banging into the trailer's sides?

I hope I'm wrong about this, because I'd love to be able to transport a large dob without having to assemble and disassemble it every time.

January 11, 2012 08:11 PM Forum: Equipment Talk

Need Information on Paracorr

Posted By Roy Troxel

I am trying to locate some good technical information (and users' opinions) of Paracorrs. All I know is that they are supposed to eliminate the "coma" effect in low f-ratio scopes. One observer told me they are "mandatory" for use with any mirror under f5.

I searched Astromart forums for "Paracorr", but didn't find anything comprehensive enough. If someone could direct me to a web site or article, I would be most grateful!

Many thanks in advance,


July 27, 2012 12:35 AM Forum: Film Astrophotography - Imaging and Processing

Need a cable release for my Canon AE-1

Posted By Roy Troxel

I need a cable release for my Canon Ae-1. I've been scanning the web, and apparently Tundra has made such a device, but they are currently out of stock. I want to photograph the aurora borealis when I take a cruise to Alaska this September.

Any advice would be appreciated.

Thanks, in advance,


August 31, 2012 01:47 PM Forum: Film Astrophotography - Imaging and Processing

Carry film through electronic airport inspections?

Posted By Roy Troxel

In two weeks, I will be flying to Alaska from Baltimore, with two stops in between. This means I might have to pass through electronic inspection points three times. How do these inspections affect photographic film? I will be carrying rolls of Kodak ISO400 & 800 film and Kodak Portra 400 film.

Thanks, in advance,


October 26, 2012 01:47 AM Forum: Off Topic Discussions

This economy is so bad...

Posted By Roy Troxel

The economy is so bad that...

I got a pre-declined credit card in the mail.
CEO's are now playing miniature golf.
Exxon-Mobil laid off 25 Congressmen.
I bought a toaster oven and my free gift was a bank.
Angelina Jolie adopted a child from America …
Motel Six won't leave the light on anymore.
A picture is now only worth 200 words.
When Bill and Hillary travel together, they now have to share a room.
The Treasure Island casino in Las Vegas is now managed by Somali pirates.

I was so depressed last night thinking about the economy, wars, jobs, my savings, Social Security, retirement funds, etc., I called the 'Suicide Hotline'.
I got a Call Center in Pakistan, and when I told them I was suicidal, they got all excited, and asked if I could drive a truck.