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Posts Made By: Walter Hamler

April 11, 2003 02:08 AM Forum: Equipment Talk

Extension tube needed

Posted By Walter Hamler
Orion Telescopes sells them in 1.25 and 2.0 sizes, 2.5 to 3 inches in extension length. Last item under accessories I believe.

Walt

April 13, 2003 02:08 AM Forum: CCD Imaging and Processing/Solar System

Clavius Large

Posted By Walter Hamler
Where is the monolith??

Walt

April 14, 2003 05:00 PM Forum: Solar System Observing

Saturns Moons

Posted By Walter Hamler
They would be moons. Because the orbital plane around Saturn is defined by its rings, the moons are in the same plane more or less (there are exceptions), so when Saturn's ring plane is tilted at its max, as now, the moons can appear to make an elipitical route around the planet, and you can see them when they are in front as well as behind the planet. (didn't mean to make such a rambling sentence, but I gradiated HS 42 yrs ago and ferget a lot)

Walt

April 21, 2003 02:43 AM Forum: Deep Sky Observing

Favorite edge on galaxy

Posted By Walter Hamler
Excellent rendering of my favorite edge on as well! What equipment and what viewing conditions?

Walt

April 23, 2003 05:01 PM Forum: Telescope Making

Bulk Stone

Posted By Walter Hamler
I get mine at a dentist office. They order and I pay them cost plus shipping. Of course it helps to know the dentist!
A 40 lb container is about 25.00, enought to make quite a few tools.

May 2, 2003 08:07 PM Forum: Equipment Talk

HELP.....Ronchi screen

Posted By Walter Hamler
Wilmann-Bell http://www.willbell.com/
They probably don't list on website but call the number. Also Orion sells them as well.

Walt

May 2, 2003 08:12 PM Forum: Deep Sky Observing

Jewel of the Andes

Posted By Walter Hamler
Was Fred Espenak along with you guys and gals also? I ask because the group shot has someone that favors Fred but the resolution is such that I can't tell for sure.

Walt

May 2, 2003 08:16 PM Forum: Birding Optics and Photos

Ok Mr Hapeman, what is this?

Posted By Walter Hamler
I'm not Mr Hapeman, but as kids we called them Piper Cubs!

Walt

May 3, 2003 01:55 PM Forum: Equipment Talk

FOV Question

Posted By Walter Hamler
afov(actual fov) is determined by objective focal lenght and the fied stop diameter of the eyepiece. In an 1.25" eyepiece, the largest size of the field stop is somewhere around 24mm, maybe 24.5. The formula for determing afov is

field stop(mm)/Objective FL * 57.3
for a 1000mm lens it is around 1.4*
for a 500mm lens it is 2.8*
I suspect someone was referring to a scope with 1000mm FL when stating the 1.33 degree max.

Walt

May 5, 2003 12:22 AM Forum: Telescope Making

8" F/5 question...

Posted By Walter Hamler
I would imagine with a 7mm chip you would not have a problem that would show up on the ccd images, and that being the case, I seriously doubt you could visually detect the difference. However, from personal experience with an 8" f/5 years ago with film, I did get noticible falloff with a 1.83 diagonal and had to go to a 2.14 to get full even illumination on 35mm film.

Walt

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