This focal reducer is made to attach to the rear cell of Schmidt-Cassegrain or Maksutov-Cassegrain telescopes. The Celestron is both a corrector and focal reducer and the Antares is just a focal reducer. As per the OP I still can't see any reason to buy the Celestron for significantly more $$$. All Rights Reserved. Will not focus with the stuff I have. Once installed, you can add additional accessories like T-Adapters, 1.25 Visual Back, Star Diagonal, or Off-Axis Guider. A couple of tiny dust particles between lens elements, uneven lens edge blackening, very minor coating blemishes, or even a very small fine lens scratch or two are very common in this Antares product and must be accepted as normal for this item. I'd favor the Japanese Celestron version over the others that are commercially available. To further factor out my natural astigmatism (I normally wear glasses while observing), I did the tests with my regular progressive lenses, single vision glasses I use when observing, and naked eye. Get ready for a night of astroimaging with your mount faster than previously thought possible with All-Star Polar Alignment. Perfect for the serious student, professional scientist and discriminating hobbyist. Practical Considerations of Focal Reducers, 4.2 Back Focus Requirements of Focal Reducers, GSO makes focal reducers for their line of Ritchey-Chretien, Celestron makes a series of focal reducers for the Edge HD line, 0.75x focal reducers for these telescopes, focal reducer for an 8-inch Celestron EdgeHD, A Primer on T-Rings and T-Adapters for Astronomy and Astrophotography, Choosing the Best Telescope for Beginners 2023, Top Night Sky & Astronomy Events in August 2022, Top Night Sky & Astronomy Events in July 2022, Selecting a Baader Planetarium Star Diagonal, A Guide to Choosing Astronomy Eyepieces for Binoviewers, Choosing a Magnifying Finder Scope for Your Telescope, A focal reducer will provide its design reduction factor only when it is placed at the exact working distance from the focal plane of the eyepiece or camera, Reducing the operating distance, that is, moving a focal reducer closer to the eyepiece or camera increases its reduction factor, or conversely reduces the amount of focal reduction. I have the Antares and am not unhappy with it, but for AP I would want more back focal distance if those numbers are accurate. Because most modern Newtonians already have relatively fast focal ratios, these telescopes do not usually use focal reducers. These 0.63x focal reducers were originally designed to optimize for an image circle to match 36mm x 24mm film or its digital equivalent for astrophotography. These reducers can also be used for visual observing with SCT scopes with eyepieces with a field stop as large as 24-27mm. However, it will not thread into William Optics accessories, and with GSO it is a hit or miss. 2.2 Using a Focal Reducer at the Working Distance, 2.3 Adjusting the Reduction Factor of a Focal Reducer, 3.3 Focal Reducers for Compound Telescopes, 3.5 Focal Reducers for Ritchey-Chretien and Field Flattened Scopes, 3.6 Focal Reducers in 1.25" and 2" Barrel Formats, 4. Celestrons aplanatic EdgeHD optics revolutionized astroimaging. With both, using the same diagonal set-up, the exact same stars were visible at the very edge of the FOV. In terms of reduction and correction which are what reducer/correctors are supposed to do both are superb. Increasing the operating distance, that is, moving a focal reducer away from the eyepiece or camera reduces its reduction factor, or conversely increases the amount of reduction. Reducer - Corrector To calculate how much back focus spacing you need to add, take the thickness of the filter and divide it by 3. They never really recovered from selling a few 15 years back with element reversed. The Reducer/Corrector is easy to install by threading the unit onto the rear cell of your Schmidt-Cassegrain telescope (or the reducer plate of the C11 and C14). which looks like the same one. However, manufacturers virtually never provide this specification. Never noticed any anomalies with this unit. Reproduction without permission prohibited. Weasner's Meade and Antares Focal Reducers Review The lens that the ZWO comes with give a perfect wide angle image of what is in front of it. Nebula Filters. I have the Japanese version and although I haven't used it in quite awhile, the views through it were superb with no internal reflections at all. These RC reducers cannot be used with other types of telescopes. This also resulted in the clear aperture of the Antares being about 39-39.5mm, versus the Celestrons 41mm. If you are using a camera that has a back focus of less than 55mm, additional spacer rings will be required between the reducer and the camera. Photographically you also get a wider field and much shorter exposures. He also holds a Ph.D. in engineering physics from McMaster University. OPT Product Number: AE-SCTFR specifications Warranty 2 Year Warranty Works as advertised! We have placed cookies on your device to help make this website better. Since the focal length of the reducer, FR, is fixed, as d2 increases then MR decreases. Again, to my surprise, there was absolutely no difference between the Celestron and Antares on any star. Celestron is considered better in terms of QA, less likely to come with free dust, hair or fingerprint. Figure 6 shows a 1.25" focal reducer from GSO configured with a ZWO ASI224MC camera. Any comments gratefully received. First, let's have a look at some key optical parameters are needed to understand focal reducers. This is the distance at which the reducer must be placed in front of the eyepiece or camera focal plane in order to operate at the design reduction factor. This would tell us exactly how well aberrations are corrected. They provide 0.75x focal reducers for these telescopes that takes an f/8 instrument down to f/6. However, these will not impact optical performance. https://www.celestron.com/products/reducer-corrector, //cdn.shopify.com/s/files/1/1935/4371/products/94175_reducer_corrector_01.jpg?v=1603736883, //cdn.shopify.com/s/files/1/1935/4371/products/94175_reducer_corrector_01_medium.jpg?v=1603736883, Popular Science by Celestron StarSense Explorer DX 5" Smartphone App-Enabled Schmidt Cassegrain Telescope, Advanced VX 8" Schmidt-Cassegrain Telescope, C9.25 Optical Tube Assembly (CGE Dovetail), Advanced VX 6" Schmidt-Cassegrain Telescope, Advanced VX 700 Maksutov Cassegrain Telescope, CGX-L Equatorial 925 Schmidt-Cassegrain Telescope, CPC 1100 GPS (XLT) Computerized Telescope, CGX-L Equatorial 1400 Schmidt-Cassegrain Telescope, CGX-L Equatorial 1100 Schmidt-Cassegrain Telescope, CGX Equatorial 925 Schmidt-Cassegrain Telescope, CGX Equatorial 800 Schmidt-Cassegrain Telescope, CGX Equatorial 1100 Schmidt-Cassegrain Telescope, CGEM II 1100 Schmidt-Cassegrain Telescope, Advanced VX 9.25" Schmidt-Cassegrain Telescope, Advanced VX 11" Schmidt-Cassegrain Telescope, Not compatible with #93648 Off-Axis Guider, not compatible with #93519 2" Mirror Diagonal (discontinued), Currently not compatible due to mechanical interferences. When you said, "in some cases" a focal reducer also works as a flattener/corrector, are you saying that not all focal reducers are flatteners/corrector? No experience with the Antares reducers, but I haven't personally seen a difference between Celestron and my current pair of made in Japan Meade reducers. I've never found my 0.63 reducer causing CA when used with my SCT. Keep in mind that these differences were very subtle, and could be due to normal variations in coatings among different runs, and not necessarily unique to the brands. For me, I was looking for, and planning to keep, the one that yielded the greatest reduction. Style: 800-483-6287 ED glass is specially formulated and contains rare-earth compounds that greatly reduce a visual defect called chromatic aberration. Still not sure what is the right gear for you? More aggressive reduction, or using these reducers with larger sensors, will result in aberrations and distortions near the edge of the image. If the focal reducer is to be used for visual observation, the visual back is threaded onto the eyepiece side of the reducer, and then a star diagonal and eyepiece are installed as usual. When placed in the focal plane in front of a camera or eyepiece, a focal reducer leads to a wider field of view and a brighter image of extended objects, which is important for reducing the exposure times when imaging faint extended objects like nebulae or galaxies. You can probably eke out 1.2 without noticing serious vignetting, which is a field stop of 31.5mm. However, doesn't fit in the telescope and even if it did wouldn't work. It threads onto the rear cell of 5" to 16" Celestron and Meade Schmidt-Cassegrain telescopes, making it possible to have a dual focal ratio instrument without sacrificing image quality. . This rugged, 3-in-1 device features a true tactical 3-mode flashlight, a hand warmer, and a portable power bank for recharging your personal electronics on the go. Brightness, color, and contrast were subtly different, but could be as much the day they were coated as any real difference in the two brands. I use the same back spacing for both on a small 6" Celestron SCT. This is a. In every configuration, there were essentially parfocal, requiring only a tiny fine focus adjustment when changing correctors. Turn it on and push Align. In about three minutes, youre ready to observe! But in the end they both do pretty much the same thing and it sounds like any performance difference is subtle. Upgrading the Focuser of Your Schmidt-Cassegrain Telescope - Agena Astro They are designed (assuming you are referring to the f/6.3 version) for the f/10 light cone. If I had to guess, the difference is maybe 10-15 grams. My experience is that CN sellers are way above those listing elsewhere. Just one question. . As a real-world example plot showing the above relationships, let's look at the 1.25" GSO focal reducer that provides a design reduction factor of 0.5x. In the 1960s, Celestrons founder, Tom Johnson, created groundbreaking new telescopes never before seen on the consumer market. As I understand it, compared to the old Meade SCT's, the ACF is already "coma corrected", so the standard Meade, Celestron etc F6.3 focal reducers are not suitable and will only worsen the images. Start here to find the perfect telescope for you! Can these economical focal reducers from GSO and other vendors result in good images? This focal reducer from Celestron reduces the effective focal length by 0.63X Enjoy the wider field of view & faster exposure times at f/6.3 with f/10 telescopes f/11 telescopes, such as the C14 will perform at f/7 The Celestron f/6.3 Reducer has four fully-multicoated elements Reduce your exposure times by a factor of 3! Besides observing from his heavily light polluted backyard in Los Angeles, Manish enjoys conducting astronomy outreach programs in local schools. Request stock alerts and we'll let you know when the item is back in stock. Focal reducers for refractors with focal ratio of f/7 to f/9, roughly, have a design reduction factor of about 0.75x to 0.8x and produce a flat field by correcting for the curvature of the objective lens. Also read the reviews here, including those at 4 stars. The review is a subjective visual impression, which is interesting but not best evidence. The price for an item/offer must be listed and valid at the time of match. And when d1 = FR, that is, when the focal reducer is placed at a distance from the focal plane of the objective that's equal to the reducer's focal length, the focal length of the combined optical system is Fo, so it acts as a 0.5x reducer. Right off the bat, I was struck by how similar the two R/Cs were. They are also less expensive than many external focusers of similar build quality. It's easy! Fastar Technology allows imagers the option of drastically increasing the speed and sensitivity of their Celestron optical tube, allowing bright, detailed images with short exposures. Download the Celestron PWI Telescope Control Software. The focus barely shifts between filters and I suspect any shifts I do get are down to the filters and changes in temp. The Antares FR2-0.7X is the same 4-element f/6.3 lens system used for f/10 Schmidt-Cassegrain telescopes but in a 2" barrel threaded for standard filters.
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