Telescope Basics (Reflector, Refractor, Schmidt-Cassegrain)

| March 31, 2012 | 23 Comments

Beginners Guide and Tutorial for Reflector, Refractor, and Schmidt-Cassegrain telescopes, Alt-Azimuth and Equatorial mounts, benefits, and comparisons.
Video Rating: 4 / 5 Each kind of telescope gathers light in a different way. Here’s why you might choose one over another. This is an episode of “The Star Party,” a video guide to amateur astronomy from the crew of Orion Telescopes & Binoculars. Visit http to find high quality products for amateur astronomers.
Video Rating: 5 / 5


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  1. CoolKillerClan says:

    the reflector can make a strait image whit a peace you can get from dollor store bynocularse

  2. kageypg says:

    how do you compare reflector and refractor apertures in terms of light-gathering?

  3. DeepSkyDan says:

    For the models you have selected I don’t think you will see any difference for casual observing for deep space objects. You can think of the Maksutov as a ‘folded reflector’. It is shorter and easier to handle (which means you might set it up more often). The Maksutov is not as easy to collimate (align the mirrors) as a reflector, should the need arise. The Maksutov has sealed optics, the reflector is completely open to dirt. Personally I’d choose the reflector.

  4. Huronhumedo says:

    but if I have to choose between a 127 mm catadioptric Maksutov and a 130 mm reflector what would be best to observe deep space objects (like nebulae) and galaxies? Celestron nexstar 127 slt and 130slt

  5. DeepSkyDan says:

    Actually, reflectors are the best for deep sky observations. Most world class telescopes are reflectors. As an example the Keck telescope is a 10 meter diameter reflector. Also the Hubble Telescope is a reflector. (Ritchey–Chrétien).

    Perhaps you are thinking of refractors. They are also OK for deep sky observations, but their size, weight, and cost are quickly out performed by reflectors.

  6. Huronhumedo says:

    The reflectors are not suitable for deep sky observation

  7. moneebjunior says:

    I am school Student, I want to make a telescope, you have made a really very good video. It was so much helpful for me. Thanksss

  8. DeepSkyDan says:

    @mileyselena7 I’m not aware of a reflector like that. That does not mean there isn’t any. I’m not an expert in optics 😉 Not sure of the impact and how it would affect the image quality, but a V shaped Optical Tube Assembly comes to mind where the mirror reflects to the side into the eyepiece instead of directly back up the OTA to the secondary mirror. It would be very awkward to use. The mirror effective surface area would be reduced, same problem. 1 way mirror doesn’t reflect light very well.

  9. lotsofsmarts says:

    thnk u!

  10. DeepSkyDan says:

    “Blocked means that some of the light from the Star is prevented from getting to the primary mirror because the secondary mirror is in the way. The secondary mirror casts a shadow on the primary mirror. All reflectors and Schmidt-Cassegrains have some light loss (blocked) because the secondary mirror is in the center of the light path.

  11. lotsofsmarts says:

    what is the “blocked” ?

  12. SaturnAndItsRings says:

    seems like the catadioptrics scope is the best!

  13. arvndmehta says:

    Very nice explanation. Thanx.

  14. americanhindi says:

    why no voice?

  15. oriontelescopes says:

    Hello, I’ve seen some image erecting adapters included with very cheap department store reflectors, but they generally have very poor optics. If one exists that has better optics, I’ve never seen it on the market The reflector design is a fantastic one for astronomical purposes, but it really wasn’t designed for correct image daytime viewing, unless you rotate your head into an uncomfortable angle. I’m sorry I don’t have a better solution for your telescope.

    Orion Telescopes

  16. TheMeanEYE says:

    Is there a way to flip image then? I’ve read somewhere online that there is but not sure how that thing is called. 😀

  17. oriontelescopes says:

    Hi TheMeanEYE,

    Unfortunately, prisms will not work on reflectors.  The light comes out of the focuser by only a small amount, but the prism requires the light to comes several more inches through it, so the eyepiece will never reach focus. Prisms work on refractors and cassegrains because the light comes much farther out of the focuser.

    Orion Telescopes

  18. TheMeanEYE says:

    Can prism be used on reflector to flip the image back to normal?

  19. beatlessexy says:

    Thank you for this! I’m saving up for a telescope, and this information will come in handy in helping me decide which kind of telescope to get. :)

  20. urilycon says:

    Great summary, thank you.

  21. KIKITO1983 says:

    excellent video ! thankyou so much u saved me money XD

  22. label1177 says:

    Thanks :D

  23. shentakuo2 says:

    Very good video.

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