What is a telescope?

Astronomers utilize a telescope as a device to observe objects in the distance. Most telescopes, and all large telescopes, make use of curved mirrors to accumulate and concentrate light from the night sky. The first telescopes were designed to concentrate light by using curved pieces of transparent glass, otherwise known as lenses. So why do we resort to mirrors nowadays? One reason is that they are lighter and can be made more smoothly, as opposed to lenses.

The reflective surfaces or lenses of a telescope are referred to as “optics”. Highly effective telescopes are capable of detecting even the faintest and most distant of objects. To do so, the optics – either mirrors or lenses – need to be very substantial. The larger the mirrors or lenses, the more light the telescope can collect. The light is then focused by the shape of the optics. It is this light that we observe when we peek into the telescope.

Latest eBay Listings for Telescopes on 7th February 2023

Right Now on eBay Telescopes
We have the detailed installation manual and video installation instructions to teach you. It’s a great astronomy gift for beginners and it will encourage them to love learning about space. The 3x Barlow lens trebles the magnifying power of each eyepiece.
 For those who want to enjoy outdoor activities in the garden,you deserve to have SV503 80ED telescope. SV503 80ED telescope’s objective lens features an S FPL-51 extra-low dispersion glass ED element, which virtually eliminates chromatic aberration. This results in the great color correction for an ED doublet lens. A thoroughly though-out design and high-quality mechanical components. This very special SV503 telescope provides astrophotographers, visual observers or nature watchers with bright, wide field views when observing starry skies or nature watching. .
The popular SV503 series refractor will provide the best optical quality, whether you use it for Deep-Sky Object or Planets, visual or photography; The compatible SV193 reducer will increase the field of view and improve the image flatness, which is essential for deep-sky photography; The SV165 guide scope is very mini and easy to use, widely used in different Astro-observations; The side dovetail slot provides you with an easy way to install the finder.
ED(Extra-low Dispersion) S-FPL51 is built in SV503 astronomical telescope. ED glass minimizes the effects of the secondary spectrum and reduces chromatic aberration to a remarkable degree. The high-quality 2-Element objective provides sharp and high-contrast images for travel and mobile use. Super Multi-coated is claimed as a remarkable seven-layer lens coating process that cuts the reflection ratio down to just 0.2% per lens surface. The result is a dramatic improvement in both color fidelity and brightness and the elimination of flare and ghost images.   .
Raptor 61 Telescope. Great condition no scratches. Attachment for a guide cam/auto guider. Also includes an electronic auto focuser.
One of the last refractors still made by Vixen in Japan before Celestron moved to China to lower prices. Excellent optics with original dew cap and shield. NO dents almost scratch free. Only one white mar which could probably be polished out.
SkyWatcher S30300 EQ6-R Pro Mount, Telescope Accessory, White.
It features a German Equatorial mount with a slow-motion altitude rod for smooth and accurate pointing. Adjust rod to desired position, then easily secure by tightening cross knob. Focus Type Manual Focus.
That’s why Celestron’s engineers created NexStar SE’s unique, patented single fork arm mount. It’s perfectly portable and makes setup quick and easy. What’s more, the NexStar SE breaks down into several lightweight and compact pieces, making it easy to transport, even in small vehicles.
8 1.25 Plossl eyepieces. 40mm, 32mm, 25mm, 20mm, 17mm, 12.5mm, 10mm, 7.5mm. 9x50 illuminated crosshair finder, barlow lens basic eyepiece filter set. PICKUP ONLY JONESVILLE, MI 49250.
NexStar Alt-Az GoTo Mount. Database: 40,000 objects, 200 user defined programmable objects. Enhanced information on over 200 objects. Slew speeds: Nine slew speeds. Optical coatings: StarBright XLT. Secondary mirror obstruction by area: 14 percent.
StarSense Explorer app automatically generates a list of objects currently visible. StarSense Explorer works with most modern smartphones, including iPhone 6 and up and most devices running Android 7.1.2 or later manufactured since 2016.
See the rings of Saturn, gaze on Jupiter and its many moons, study the details of our own moon. Or venture further into space, seeking out large globular clusters, bright double stars and glowing nebulae.
【Large Aperture】70mm aperture and 700mm focal length provide more lights and clearer images, fully coated optics glass lens with high transmission coatings, provides stunning views and protect your eyes.
Gskyer Telescope.
Within a few seconds, reveal the great red spot of Jupiter and its colored bands. The eQuinox 2’s catalog of more than 5,000 objects will provide you with detailed information for each of your targets.
Celestron Telescope/ Stand
Celestron Telescope/ Stand
$200.00
 
(0 bids)
$359.00
Kit Weight: 15 lbs (6.8kg). Accessory Tray: Yes. Mount Type: Manual Alt-Azimuth. MOUNT INFO Optical Tube Length: 889mm (35"). Optical Tube: Aluminum. Light Gathering Power: 265x. Resolution (Dawes): 1.02 arc seconds.
102mm objective lens diameter and f/7 focal ratio telescope OTA; large objective lens brings more lights into the scope body and you will get more bright and clear image Doublet air spaced achromatic S-FPL51 ED glass provides you less chromatic aberration image,Ultra-wideband coating: On every glass/air surface, we use the best multi-coating to ensure maximum contrast. Crisp Image;Super Multi-coated ultra wide band multi-layer coating technology;102mm aperture optics and retactable lens hood deliver bright wide-field images with sharp resolution 90mm back focus; it comes with dual focus rack and pinion focuser with focus knob cover; you can get precious focus easily Package includes;102mm refractor OTA;2 inch to 1.25inch adapter;Metal hoop and dovetail;objective focuser wheel cover;.
 For those who want to enjoy outdoor activities in the garden,you deserve to have SV503 80ED telescope. SV503 80ED telescope’s objective lens features an S FPL-51 extra-low dispersion glass ED element, which virtually eliminates chromatic aberration. This results in the great color correction for an ED doublet lens. A thoroughly though-out design and high-quality mechanical components. This very special SV503 telescope provides astrophotographers, visual observers or nature watchers with bright, wide field views when observing starry skies or nature watching. .
1. The appearance of the telescope is baked with high-end fine-grained paint, with exquisite appearance and delicate feel 2. The objective lens features a S-FPL51 extra-low dispersion glass ED element, which eliminates chromatic aberration. This results in the best color correction for an ED doublet lens 3. The lens adopts optical processing and low polishing technology, which is carefully carved 4. The deceleration ratio of the two-speed 2'' toothed focusing seat is 1:10, which makes it easy to achieve accurate focus.
1. The appearance of the telescope is baked with high-end fine-grained paint, with exquisite appearance and delicate feel 2. The objective lens features a S-FPL51 extra-low dispersion glass ED element, which eliminates chromatic aberration. This results in the best color correction for an ED doublet lens 3. The lens adopts optical processing and low polishing technology, which is carefully carved 4. The deceleration ratio of the two-speed 2'' toothed focusing seat is 1:10, which makes it easy to achieve accurate focus.
This results in the great color correction for an ED doublet lens. Top-quality Material; The appearance of the SV503 OTA is baked with high-end fine-grained paint; with exquisite appearance and delicate feel;all machined by CNC.
The popular SV503 series refractor will provide the best optical quality, whether you use it for Deep-Sky Object or Planets, visual or photography; The compatible SV193 reducer will increase the field of view and improve the image flatness, which is essential for deep-sky photography; The SV165 guide scope is very mini and easy to use, widely used in different Astro-observations; The side dovetail slot provides you with an easy way to install the finder.
ED glass minimizes the effects of the secondary spectrum and reduces chromatic aberration to a remarkable degree. This results in the great color correction for an ED doublet lens. Copernicus Crater.
Criterion Dynamax 8 With Tripod And Accessories. I’m unable to test it I don’t know if is missing some parts sold as is
Celestron NexStar 5SE 10 Telescope. W/ tripod stand. All user manuals and cd. Telescope was 3 times.
Provides the optimal color correction to achieve clear and beautiful images. The 1:10 microdaction is ideal for astronomical photography, and it is possible to focus on accurate focus. 2 "RAP (Rack and Pinnion type) focuser can safely place heavy photographic accessories.
Celestron NexStar 5SE 10 Telescope. Still in box. Unused.
Adjust rod to desired position, then easily secure by tightening knob.
orion dobsonian xt plus 8 telescope.
FOR PARTS OR REPAIR. MISSING PIECES! TRIPOD IS IN GOOD SHAPE. LOOK AT ALL PICTURES TO MAKE YOUR ON JUDGMENT ON CONDITION. FEEL FREE TO ASK FOR MORE PICTURES OR ANY QUESTIONS. THANKS FOR LOOKING. MESSAGE FOR LOCAL PICK UP. NEAR DALLAS FORT WORTH TX
Celestron NexStar 130SLT f/5 Computerized Telescope We received as gift but already had a similar telescope
Sky-watcher Skymax 127mm Maksutov OTA. This is a used modded skywatcher skymax 127 maksutov telescope and performs amazing with visual astronomy and astrophotography. This telescope comes with mounting rings so you can change the orientation of the focuser and balance of the telescope. This performs amazingly on the planets and moon.
Dovetail bar is mounted on the left side of optical tube. It is new and you will be the first to enjoy genuine Celestron quality. Celestron 4". No accessories, computer, mount, or tripod are included.
No accessories are included. You will need a diagonal and eyepiece to use this scope. An OTA is an optical tube assembly. No mount is included. Celestron 8". We are an authorized Celestron distributor.
This OTA willnot work on NexStar 4SE and 5SE mounts. What you see is what you will receive. No accessories are included. You will need a diagonal and eyepiece to use this scope. An OTA is an optical tube assembly.