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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? The Antares focal reducer comes in small box. Antares f/6.3 Focal Reducer for SCTs - Awesome Astro 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. Thanks for any advice or experience you could share. Thanks for pointing this out. This was most noticeable on the eyepiece end of the RC, where the metal rim surrounding the lens was about 1mm thicker than on the Celestron. The Celestron f/6.3 is ~150 compared to the Antares at ~70. I own both and concur heartily. I have an 8SE, and am thinking about getting a focal reducer. Does anyone have any experience with the Celestron and Antares focal reducers? Thanks for the extremely valuable article. All rights reserved. because they really dont matter. Focal Reducer, 2", 0.7X - Antares We only send interesting emails and will never sell your data. It seems right to put some distance between the camera and the focal reducer, right? That was fun. Even though they may have been slightly dimmer, galaxies were a bit easier to tease out of the urban light soup I deal with. I found both to be very good. Check out our 2022 telescope buying guide here! When the camera sensor is placed at this distance, the reduction factor of these reducers is 0.75x. I doubt there is any difference between the Antares and the Celestron except price. It's usually specified from the base of the mounting threads on the reducer's housing, and this is the most practical way of providing this specification. I would not use the reducer with a 2" diagonal or eyepiece in the C6. 800-483-6287 Have a promo code? Reducer Lens .7x - EdgeHD 1100. My Celestron was made in China and the Antares in Canada. Reducer - Corrector Learn More. However, even though the imprint on the item states "Reducer / Corrector" please note that his is a reducer only. Reproduction without permission prohibited. Performance wise what differences might there be using the reducer on a smaller scope. 3. Once installed, you can add additional accessories like T-Adapters, 1.25 Visual Back, Star Diagonal, or Off-Axis Guider. This article explained the basics of how focal reducers work with various kinds of telescopes and how their working distance affects their reduction factor, and it provided sufficient detail to help amateur astronomer choose and use the right focal reducer for a particular application. Specially-designed focal reducers are available for use with these telescopes. Generally, views through the Antares seemed a little more transparent and brighter. They only publish the value of D, the working distance (sometimes called the back focus distance) and the design reduction factor MRD. OPT Product Number: AE-SCTFR specifications Warranty 2 Year Warranty Works as advertised! However, doesn't fit in the telescope and even if it did wouldn't work. The Antares is supposed to be pretty comparable. Any comments gratefully received. Celestron or Antares f/6.3 focal reducer for SCT? And when used in some refractors, the field flattening is not as accurate as it is in the f/10 SCTs. Try & buy if you like - usual mates rates. Fortunately, my neighbors are not out in their backyards at 11 pm, or they may have thought I was torturing a small mammal. Equation 6 & 7 item two & three does not make sense, both say increase its reduction (one should say reduce its reduction?). If used before or beyond the working distance, unwanted image distortion may result, especially when using cameras with larger sensors. Download the Celestron PWI Telescope Control Software. (Note: Using the simple equations above, the focal length of this reducer can be estimated to be about 350mm). Yet, the Antares still easily and fully threaded without any hitches. The Buyer's Guide To Eyepieces at the top of the Eyepieces forum has a column for this spec. Sign up for OPT news, exclusive offers, and updates on the latest gear! This appendix summarizes how this works based on simple equations from the book Telescope Optics by Rutten and van Venrooij. You don't need to follow these equations to use a focal reducer, but they do show how the reduction factor changes with the placement of the reducer. Imaging - Focal Reducers and Flatteners - Page 1 - KW Telescope Theres a long-running debate in these forums and even statements from some reputable dealers that the Antares is just a reducer (even though it is labeled Reducer/Corrector), whereas the Celestron is a true R/C, which flattens the SCTs naturally curved field and provides some edge correction. The new Lithium Phosphate (LiFePO4) battery chemistry has significant advantages over other battery chemistries, great for for those Astronomers on the go. Unlike . The female end attaches to the rear cell of the telescope. Meade once made an f/3.3 focal reducer for SCT scopes. I'm going with the Celestron. CPWI has an extensive object database, employs PointXP mount modeling, and more. However, in principle, the reduction factor of a focal reducer can be varied by changing the distance from the back of the focal reducer to the camera or eyepiece. On the trail, at the job site, in the classroom, or simply sitting at home relaxing the Celestron Elements ThermoTank 3 will keep your hands toasty. Using these numbers in equation 4 in the Appendix, below, we can easily calculate that the focal length of this unit is approximately103mm (it will be 103mm plus the small amount by which the rear lens surface of the reducer is recessed beneath the reducer housing). Some faster refractors with a focal ratio of f/6, for example, only require field flatteners and not focal reducers. 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. However I've also read that the back focal distance on the Celestron is 105mm while the Antares is 81mm so they couldn't be identical. It was also a little brighter in the center of the field with subtle darkening in the outer 20% or so. As a result, the smaller tube may cut into the light cone and effectively reduce the working aperture of the telescope. There is a way to make subjective data more useful and that way is proper blind, or better still. riklaunim Members 559 3,445 Location: Poland Posted October 11, 2010 They are reported as identical. Many reducers, such as the Celestron HD focal reducer mentioned above, and many focal reducers for apochromatic refractors, are meant to be used within a few millimeters (or less) of the specified working distance to achieve the best possible image results. Quite interestingly it bears the very same engravings of the Meade 4000 r/c (including "series 4000") except for "MEADE". I must admit, as well, that I no longer place a lot of stock in the notion that Chinese optics are inferior to Japanese or Taiwanese any longer, as manufacturing technology has really leveled the playing field today, with most Chinese optics being excellent. A focal reducer does just the opposite of a Barlow lens or focal extender. This would tell us exactly how well aberrations are corrected. The Reduction Factor and the Amount of Reduction are inversely related. At a significantly lower price point, the Antares is a steal, and theres no need to upgrade to the Celestron if you already have one. They never really recovered from selling a few 15 years back with element reversed. a Tele Vue Panoptic), or a Plossl eyepiece with an apparent field of view of 50 and a focal length of 32mm. You cannot, for example, use a 0.63x focal reducer intended for a standard Celestron or Meade SCT and use it on a Celestron Edge HD or a Meade ACF. In terms of reduction and correction which are what reducer/correctors are supposed to do both are superb. Request stock alerts and we'll let you know when the item is back in stock. An f/6.3 reducer is designed to reduce the focal ratio of an f/10 SCT to f/6.3. It might work but it does not tell us anything about how well or to what extent the product works to correct the field of an SCT. Reducer Lens .7x - EdgeHD 1400 Focal reducers for refractors are easy to use. So Celestron buyers like Celestron, Meade buyers like the Meade and Antares buyer like the Antares. Unique focal reducer and field corrector lens accessory, Reduces the focal length and f/ ratio of your Schmidt-Cassegrain telescope by 37%, Provides a dual focal ratio instrument, without sacrificing image quality, Compatible with all Schmidt-Cassegrain telescopes (see compatible list in description). They are reported as identical. The lens has a knurled surface, providing a tremendous gripping surface for threading/unthreading. If it's positioned further from the eyepiece or camera and closer to the telescope objective, the reduction factor increases. F6.3 Focal reducer for F/10 or higher telescopes, 43mm aperture, 4-Element, Fully Multicoated. and you will be fine. 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). Who cares? Not a bit. All rights reserved. It features a standard male SCT thread (2" OD, 24 TPI) on one side and a standard SCT female thread on the other. However, the China 6.3 R/C has noticeable internal reflections that I haven't figured out yet. Even though the manufacturer did not specify the working distance or focal length of this reducer, it is easy to see from this plot that this item provides its stated reduction of 0.5x when it is placed at a working distance of 51.5mm between the base of the threads on the mount and the focal plane of the eyepiece or camera. You currently have javascript disabled. The author finds differences in throughput and color balance, but then says he thinks the lenses are identical and he reaches his conclusions based on very long observing session. Sky recognition technology that has revolutionized the manual telescope by eliminating the confusion common among beginners and enhancing the user experience for even seasoned telescope users. With this telescope and this focal reducer, it does not help to move to a 2" eyepiece and a 2" diagonal as the visual view will be akin to looking through a porthole within the larger apparent field of view of the eyepiece. Celestron Solar Safe filter technology is GUARANTEED SAFE for direct solar observation and has been independently tested by SAI Global Assurance Services. However, this also came at a cost, as the sky background in the Antares was slightly brighter. 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. Have always disliked the crude, noisy SCT threads, but I get it. I have/had both the Celestron (Japan) and Antares units. No retailers currently carry this product. None of this was offensive, nor did it interfere with views in any significant way. If I had to guess, the difference is maybe 10-15 grams. Product Details Antares' f/6.3 focal reducer provides a faster f/6.3 system for imaging or visual use when used with an f/10 SCT or other compatible telescopes. F 6.3 focal reducer/corrector. - Discussions - Stargazers Lounge Can these economical focal reducers from GSO and other vendors result in good images? In some cases, focal reducers also act as field flatteners by correcting for field curvature and coma of the objective lens. Figure 2 shows the effective of a focal reducer on the light from a telescope objective. What is likely is that fatigue sets in, and also that as the targets move toward or a way from the meridian there will be changes for that reason alone. More details are found in the Appendix of this article. Assuming you use the reducer with the stock 1.25" diagonal, it will operate at f/6.3. If you want to save a few buck watch the classifieds on CN. Your mileage may vary. Thank you so much for the informative article, I now understand better how to integrate my reducer into my system to get better performance. I'd favor the Japanese Celestron version over the others that are commercially available. If I had to chose one, I would base my decision on your level of light pollution perhaps the Antares for its slightly higher transmission if you live under less light polluted skies, but the Celestron for its greater contrast if you are dealing with a suburban or urban light dome. The focus barely shifts between filters and I suspect any shifts I do get are down to the filters and changes in temp.
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