Meade DS-2114AT-TC.How do they get 1000mm focal length when distance from mirror to focal point is only half that?Are they counting length of the tube before the light hits the mirror?

Answers:

From: Bill

the light enters the front of the telescope, hits the rear mirror and is reflected to the front mirror which shoots the light up through the eyepiece. thus, focal length is the distance from the front of the telescope to the back plus the distance from the back to the front mirror. so the answer to your question is yes, they are counting the length of the tube before the light hits the rear mirror. that is also true of schmidt-cassegrains, maks and any other reflectors. they just have a piece of glass at the front of the scope to direct the light differently to the primary mirror. yous still count the initial length of the tube before the light hits the primary.

Back

Add Your answer to this question:

Your name
Your answer
Confirmation code:	226 Enter the code exactly as you see it into this box.

$	Top Products

	» 8 x 20mm Spy Scope
	Price: $48 $39.99

	» Marine Night Owl Explorer
	Price: $431 $359.00

	» Night Owl Explorer Monocular
	Price: $371 $309.00

?	Questions & Answers

Resolved questions:

» Does a bat has a binocular vision?

» What is difference between binoculars and telescope?

» Does anyone know where i can find an instruction booklet for a guidesman telescope?

New unresolved questions:

» Can someone recommend a telescope for amature purposes that would be in $500 range? Is there a website where I can read reviews on various telescopes?

» How can i see the detail of the moons craters as best as posable with a small teliscope

» I just bought a Bushnell North Star 78-8831 525X3" 700mm Reflector telescope. Bushnell does not make a erecting eye piece for their reflector scopes. I purchased a zuhmell erector after Optic Planet said it would work.

» Ask a question
» Answer questions