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It is not essential to have a secondary mirror on a Newtonian telescope, but the reason there is one is for practicality. If you mounted an eyepiece at the focus of the primary mirror, your head would be directly in the light path, blocking much of the light from entering the tube. The same reason applies to cameras, but with modern CCD cameras being circular and small, it is possible to mount one at the focus of the primary mirror. Indeed, doing this may block less light than a secondary mirror would, certainly in the case of a large aperture instrument (for example 300mm and above.)
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How many mirrors does a reflecting telescope have?
A reflecting telescope only needs one mirror, the primary mirror which will focus incoming light to a single point. A digital telescope might place the digital recording media directly in front of the reflecting telescope without any additional mirrors (although perhaps some lenses). For practical purposes though, most optical telescope will have a secondary mirror that will either focus light straight back through a hole in the primary telescope mirror, or to the side of the telescope. Some telescopes, especially the large ones in observatories will have several mirrors directing the light path to the observer or recording equipment.
Why is a thermos flask made of steel?
Hot drinks are usually put in a thermos flask, so the flask needs to be made of something strong in order not to get ruined in any way, therefor steel is used.
What advantages do reflecting telescopes have over refracting telescopes?
refracting telescopes use lenses instead of mirrors. 1. chromatic aberration: when light passes through a lens it is focused at different points. Blue focuses closer to lens and red farther creating a smeared image. 2. Some light is absorbed by lenses. 3. Lenses are heavy and can only be supported by the edge. 4. Lenses must have to optically acceptable surfaces whereas a mirror only needs one.
Do ecosystems recover from disturbance through ecological succession?
because it needs time to heal
What are searchlight used for?
A searchlight (also referred to as a spotlight) is a piece of apparatus that combines a powerful light source with a mirrored reflector in order to project a powerful beam of light of approximately parallel rays of light in the direction that the user needs to see in. A common use for them is to search for people who have fallen overboard a ship at sea.
Difference between primary and secondary needs?
Primary needs are essential for survival, such as food, water, shelter, and clothing, while secondary needs are not necessary for survival but contribute to quality of life, such as education, entertainment, and travel. Primary needs are fundamental to human existence, whereas secondary needs are more related to personal preferences and desires.
What is secondary logistics?
In military terms, primary logistics serves the needs of combat troops and secondary logistics serves the needs of support troops.
What are secondary motives?
Secondary motives are based on learned needs, drives and fears. They're motives we learned to need.
What is a source of energy that needs another source of energy to produce it?
A secondary
What are the 3 communication needs that the secondary English curriculum seeks to address?
no..can you help me
What is the difference between primary and secondary needs?
I'm guessing primary need is a chore item etc. that needs to get don as the first priority. Secondary is a lesser need. Don't think this is fully true. I am just guessing
In Canada how many mirrors are required on a street legal vehicle?
The Canadian Traffic and Safety Act dictates that a vehicle only needs the rearview mirror to be street-legal. Wing mirrors and any other mirrors on a vehicle are not actually required for legality. Source: I work for the Edmonton Police Force as a Traffic Cop.
Is secondary data gathered and recorded by someone prior to the current needs of researchers?
True
How many mirrors does a reflecting telescope have?
A reflecting telescope only needs one mirror, the primary mirror which will focus incoming light to a single point. A digital telescope might place the digital recording media directly in front of the reflecting telescope without any additional mirrors (although perhaps some lenses). For practical purposes though, most optical telescope will have a secondary mirror that will either focus light straight back through a hole in the primary telescope mirror, or to the side of the telescope. Some telescopes, especially the large ones in observatories will have several mirrors directing the light path to the observer or recording equipment.
Are the courses offered in your secondary schools relevant to the needs and problems of the and nation?
yes, because all subjects that we teach in the secondary are all relevant in dealing our daily lives' activities
What are the relevant legal requirements covering the needs of disabled children and those with special educational needs?
hi i am wanting to know what the legal requirments for secondary schools for children with special needs please can you help
Are the courses offered in your secondary schools relevant to the needs and problems of the community and nation?
yes, because all subjects that we teach in the secondary are all relevant in dealing our daily lives' activities
