Start Chat We tested GSO's 1.25" 0.5x focal reducer at a variety of operating distances and calculated the field of view through a telescope to derive the actual reduction factor that is plotted below. Take control of your telescope! Years ago, I bought the Antares version, and moved over to the Celestron. However, some focal reducers can be used over a wider range of working distances, especially those with simpler optical design, and especially when used with cameras with smaller sensors. You also wont be unhappy spending the few extra bucks on the Celestron for the pretty orange lettering, particularly if you can pick one up used, as I did. Rather than a direct side-by-side, I swapped the reducers so that I was using them on the exact same, well-collimated instrument. Hmmm . Not one detectable iota of discernable difference. In the 1960s, Celestrons founder, Tom Johnson, created groundbreaking new telescopes never before seen on the consumer market. Many Ritchey-Chretien telescopes available today are made by GSO. Increase that distance, and greater reduction results and visa versa. 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. If used before or beyond the working distance, unwanted image distortion may result, especially when using cameras with larger sensors. That includes, for example, a 1.25" eyepiece with an apparent field of view of 68 and a focal length of 24mm (eg. Still not sure what is the right gear for you? because they really dont matter. The working distance (backfocus) of the Celestron f/6.3 reducer is specified to be 105mm from the base of the male SCT thread on the camera side. Please let us know what topics you are interested in. In every configuration, there were essentially parfocal, requiring only a tiny fine focus adjustment when changing correctors. The Celestron f/6.3 is ~150 compared to the Antares at ~70. Product Details. They usually have a 2" barrel that slides into the telescope focuser. I have had the Japan unit on the back of my C5 since 1994 or thereabouts. CPWI has an extensive object database, employs PointXP mount modeling, and more. Another factor to consider: focal reducers also increase the angle at which light approaches the focal plane. Steve From the SkyProdigy, a telescope so smart it can align itself, to our high-performance EdgeHD optical system, weve revolutionized the hobby of astronomy for beginners and advanced amateurs alike. As often noted in reviews and forum threads, Antares products tend to have threads that are a little less precise, and this specimen certainly demonstrated this. A few people have reported issues with the male SCT thread diameter on this item being a bit larger than necessary. For Stephen Wilkerson: The ZWO ASI120MC-S does come with a wide angle lens, HOWEVER, it is NOT intended to used when you are using the ASI120 camera attached to your telescope. Unlike SCT telescopes, Ritchey-Chretien telescopes and Celestron Edge HD or Meade ACF scopes have internal optics that provide an inherently flat field, so these telescopes require a special focal reducer than does not provide additional correction for field curvature. Most Feather Touch focusers cost between $300-$350. This also resulted in the clear aperture of the Antares being about 39-39.5mm, versus the Celestrons 41mm. If the reducer is placed closer to the eyepiece or camera than the distance D, the reduction factor decreases. Reducer - Corrector Learn More. For example, with a 0.8x focal reducer, a telescope with a focal length of 800mm will operate at 800 x 0.8 = 640mm when the reducer is placed at the working distance specified by the manufacturer. . This Antares 1.25" 0.5x focal reducer lens (tele-compressor) is used under the Orion brand name to thread into the nosepiece of Orion StarShoot Solar System cameras and StarShoot Deep Space Color Imaging Camera. If the reducer is placed elsewhere, at a position called the operating distance, the focal reduction factor will not be as advertised. Start here to find the perfect telescope for you! The same illumination you have at the edge of a 27mm field, the C8 has at the edge of a 38mm field. I've heard and read all kinds of things about the Antares being only a reducer and not a corrector, etc. The naming convention of SCT focal reducers is a little confusing. Due to the design, the Reducer/Corrector lens does diminish a small amount of field curvature common to all Schmidt Cassegrain telescopes but does not eliminate it. The C8 has no noticeable vignetting with a 32mm Plssl in the f/6.3 reducer. F6.3 Focal reducer for F/10 or higher telescopes, 43mm aperture, 4-Element, Fully Multicoated. This may be a problem if the focuser tube or the diagonal (for visual observing) is too narrow to accept light at this larger angle. Things change but when I rebought I got an Antares and it seems about the same to me. This is one of our best-selling items, and customers have reported that this product is at least as good as, and probably better than, other leading f/6.3 focal reducers sold on the market for a lot more. I have/had both the Celestron (Japan) and Antares units. The Antares focal reducer comes in small box. As mentioned in Section 2 of this guide, the reduction factor of a focal reducer depends on its position in the optical path relative to the eyepiece or camera. This should not be the case if they have their purportedly different focal lengths. Over the course of a several nights of general observing, I swapped back and forth between the Antares and Celestron R/Cs on a wide variety of objects open clusters, brighter galaxies, a couple of nebulae, and globular clusters as well. GSO, for example, has a 0.75x reducer for RC scopes with a back focus of 80mm, which is usually enough room for a wide range of astronomy cameras and accessories and spacers as needed. 2023 OPT Telescopes. Yet, the Antares still easily and fully threaded without any hitches. This appendix summarizes how this works based on simple equations from the book Telescope Optics by Rutten and van Venrooij. if the illuminated field is 27mm wide without the reducer, it will be 27 x 0.63 = 17mm with it in place. 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. But while the image gets brighter, the size of the image circle gets proportionately smaller. Theoretically each of these combinations all varied-length light paths should have resulted in slightly different reductions between the Celestron and Antares, since they supposedly have different focal lengths. Celestron's EdgeHD reducers feature a custom 5 element optical design engineered to maintain the flat-field performance of our award-winning EdgeHD optical system. How about for visual observers? Figure 6 shows a 1.25" focal reducer from GSO configured with a ZWO ASI224MC camera. Specially-designed focal reducers are available for use with these telescopes. Observing the microscopic world has never been easier! 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). Ive owned Celestron, Meade, and Antares models over the years at least a couple of each. Unleash the full pointing accuracy of your Celestron computerized telescope with a specialized telescope control software suite. Also read the reviews here, including those at 4 stars. You currently have javascript disabled. The designed reduction factor (0.5x in the case of the GSO reducer example above) should be considered a rule of thumb or approximate value in most cases, rather than a very precise number. All rights reserved. This focal reducer is made to attach to the rear cell of Schmidt-Cassegrain or Maksutov-Cassegrain telescopes. This telescope control software replaces the hand control and allows the user to remotely control their Celestron computerized telescope from their personal PC or laptop. Most amateur astronomers are familiar with a Barlow lens (or a focal extender), a negative or diverging lens that effectively increases the focal length and the focal ratio of a telescope's objective lens. I use the Celestron version and it seems OK for both visual and imaging. . The female end attaches to the rear cell of the telescope. This part is no longer in production, but it is sometimes available used and may be used with cameras with smaller sensors. Most refractor manufacturers such as William Optics, Tele Vue Optics, Explore Scientific, Sky-Watcher, William Optics, and Stellarvue make their own focal reducers optimized for use with their telescopes. 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). If you want to save a few buck watch the classifieds on CN. We do not price match competitors if they are out of stock. 3. This would tell us exactly how well aberrations are corrected. Advanced designs for Schmidt-Cassegrain scopes such as the Meade ACF or Celestron Edge HD have optical elements in the tube to correct for coma and field flatness. An f/6.3 reducer is designed to reduce the focal ratio of an f/10 SCT to f/6.3. . Contiguous US Customers:All items we sell ship for free within the Contiguous US. Given past experience with them, I decided not to include the Meade version in my little experiment, as I have never met one I liked from getting one of the too-short focal length models, to one with some overflow cement in the doublet, to focus difficulties with some eyepieces. It's an either/or proposition: reducer and 1.25", or 2", but not 2" and reducer. Imagine having two telescopes in one a long focal length instrument for lunar and planetary work and a short focal length scope for deep sky observing and astrophotography. It seems right to put some distance between the camera and the focal reducer, right? I use it on my C8 SCT with a 1000d, and it seems to do everything written on the tin. Hence, there is a chance that you may not be able to thread your SCT diagonal or other SCT accessory on to this reducer for these or for any other brand. To test this, I used three set-ups: 1. For the best experience on our site, be sure to turn on Javascript in your browser. Figure 2 shows the effective of a focal reducer on the light from a telescope objective. Any comments gratefully received. Based on Test 1 and Test 2, I think there is perhaps more validity to opposing statements here in these forums that the Antares and current China-made Celestron do, indeed, have exactly the same optics just with different housings and branding. More aggressive reduction, or using these reducers with larger sensors, will result in aberrations and distortions near the edge of the image. Assuming you use the reducer with the stock 1.25" diagonal, it will operate at f/6.3. My experience is that CN sellers are way above those listing elsewhere. I am a purely visual observer, so will evaluate for visual use only. The Celestron is both a corrector and focal reducer and the Antares is just a focal reducer. More about this below. If I had to go out on a very thick limb, I would have to say that these two reducers/correctors are, indeed, identical the exact same glass in slightly different housings with different lettering. By 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. Antares or Celestron? This fully multi-coated lens provides maximum light transmission with near full-field illumination. In both cases will end with a similar tfov. I was going to measure the difference in grams, but my lovely wife caught me trying to use her precious, high-tech kitchen scale for the cause, and put the kibosh on it. However, because the field curvatures in refractors and SCTs vary a lot, I would predict unpredictable effects inre: field curvature. He tested this on an 8 Celestron , I have a Celestron 6SE. Please Log in to save it permanently. No idea what the issue is. Copyright 2021 Stargazers Lounge Reducer - Corrector The most popular accessories for your new telescope! I've only used it a few times but it looks good to me. For this shoot-out, I used a standard Celestron C8 with Starbright coatings. You attach the focal reducer to the rear port on a SCT and can keep it covered. They are commonly available in 1.25" and 2" threaded cells that conveniently thread into the nosepiece of a compatible camera or the barrel of an eyepiece. In some cases, focal reducers also act as field flatteners by correcting for field curvature and coma of the objective lens. Since then, Agena has become one of the leading online retailers of telescopes and astronomical accessories worldwide. For me, I was looking for, and planning to keep, the one that yielded the greatest reduction. But I am rusty, can you condense a bit for me please? No negative issues to report. 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. We have placed cookies on your device to help make this website better. We have corrected # (iii) after equations 6 & 7. I wonder whether, for example, Antares focal reducer for SCT belongs to the latter category. The camera side of the focal reducer is threaded for a T-adapter with wide M48 threads, or in some cases, with smaller M42 threads. If you want to use them for visual - try maybe long focal length eyepieces rather than the reducer. Great report and verifies what I had thought all along, Fortunately, my neighbors are not out in their backyards at 11 pm, or they may have thought I was torturing a small mammal. Celestron makes a series of focal reducers for the Edge HD line that are matched to the 8", 9.25", 11", and 14" apertures of these scopes. control and Sky Viewer display makes selecting your target easy. Telescope Optics, Rutten and van Venrooij, Chapter 15, Willman-Bell (1988). So, this past week I challenged the Antares and Celestron models to a head-to-hear on my C8 on some decent nights of good seeing and transparency in my Bortle 5-6 urban skies. Celestron or Antares? That is definitely a 2" eyepiece, but it is not a large or long focal length 2" eyepiece. The distance d2, which measures the position of the new focal plane of the objective from the back of the focal reducer is given by Equation 5: In these equations, d1, d2, and MR are all variables that depend on each other through Equations 2 and 4. The telescope side of the barrel is often threaded with an M48 x 0.75 thread for standard 2" astronomy filters. Celestron is considered better in terms of QA, less likely to come with free dust, hair or fingerprint. Details: The item must be the identical item, brand name, size, weight, color, quantity and model number. I don't know. For the best experience on our site, be sure to turn on Javascript in your browser. Possibly the design of the Antares was changed .. Perfect for the serious student, professional scientist and discriminating hobbyist. Celestron Solar Safe filter technology is GUARANTEED SAFE for direct solar observation and has been independently tested by SAI Global Assurance Services. Celestron or Antares f/6.3 focal reducer for SCT? October 11, 2010 in Discussions - Scopes / Whole setups. InternetSales@optcorp.com. However, some focal reducers can be used on other models of telescopes, but this is not always possible. It has only one cover, which surprised me. Can you help me? They provide 0.75x focal reducers for these telescopes that takes an f/8 instrument down to f/6. ED stands for "extra-low dispersion," which refers to the composition and optical properties of the glass used for the lenses. Oceanside Photo & Telescope wants our customers to shop with confidence knowing that you will always get the best deal available. But is there a difference in quality between the Antares and the Celestron or Meade focal reducers? Focal reducers also move the effective focal plane of the objective inward, that is, towards the objective (see Figure 1). There may have been an almost imperceptible difference, but the Antares and Celestron were producing precisely the same reduction. This is the simplest way to attach your ASI121 to your telescope. Sign up to get exclusive deals, observing tips, and new product announcements. These reducers can also be used for visual observing with SCT scopes with eyepieces with a field stop as large as 24-27mm. Each focal reducer has a fixed specification called the working distance or required back focus. I think there may be some confusion here, because Antares makes a variety of reducers for eyepieces and scopes in addition to this SCT R/C but this definitely is a reducer/corrector. For me the Antares was a little brighter and had the least scatter by a bit so the better coatings won. Article Agena AstroProducts, 2019. 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. 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. Meade and Celestron both sell such SCT-T adapters with the correct optical length. The Reduction Factor and the Amount of Reduction are inversely related. One problem with getting opinions is that most of use do not have both reducers or have never done a side by side comparison. Edited by bluewater, 05 September 2020 - 11:27 AM. A little longer light path with a 2 Baader click-lock, low profile 1.25 adapter, and the 1.25 diagonal; None of this was offensive, nor did it interfere with views in any significant way. This award-winning optical system reduces visual defects like field curvature and coma, creating an ultra-flat field for pinpoint stars all the way to the edge of todays largest imaging sensors. This innovative software solves the time-consuming problem of trying to pinpoint the North Celestial Pole. 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. Some are available in 1.25" barrel format but with C threads. Today, our world-class team of optical and electronic engineers continues to push the boundaries of technology. We only send interesting emails and will never sell your data. If used with other f/ratios, the field flattening characteristic may be unpredictable. 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. Images in the Celestron tended to appear ever-so-slightly dimmer (maybe? I've seen some older threads saying that the Celestron, Meade and Antares FRs are all the same and manufactured in the same factory. 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. For the best experience on our site, be sure to turn on Javascript in your browser. And, the reality is that every F/6.3 RC out there Celestron, Hirsch, Astromania, etc., etc. No results, please adjust your filters. The previous post shows the reducer on what appear to be two different refractors. There are also third-party vendors such as Hotech. But in the Japan version I have never noticed any anomaly like the ghosting in the China R/C. Planetarium software package which provides easy-to-understand explanations and impressive visuals of all kinds. Sign up for OPT news, exclusive offers, and updates on the latest gear! However, with appropriate spacers and a camera with a known back-focus, it is easy to determine the exact amount of focal reduction for a given setup (some imaging software packages will also let you derive this from images). They are designed (assuming you are referring to the f/6.3 version) for the f/10 light cone. Description. 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. It is recommended for . M44 was a perfect target for this, as its large size maxes out the FOV on a C8 with a corrector, and its bright stars make great targets for measuring the very edge of the visible field. Right off the bat, I was struck by how similar the two R/Cs were. Also, the focusers of most Newtonians do not have enough in-travel to accommodate a focal reducer. Yellow and orange members of open clusters stood out a bit more as the various stars displayed their individuality. On the camera side, the focal reducer has male M42x0.75 or M48x0.75 threads that attach directly to the T-ring (with an M42-M48 adapter if necessary). Focal reducers for refractors are easy to use. Some coma is visible in the corners, but the image is quite good for EAA applications. What I do know is that the Antares and the Celestron samples that I have perform exactly the same from the center right out to the edges. Our proprietary StarBright XLT optical coatings dramatically increase transmission, up to 97.4% on our Schmidt corrector lenses. Normal shipments will resume on Monday, March 6, 2023. nleash the full pointing accuracy of your Celestron computerized telescope with a specialized telescope control software suite. Nowadays I tend to use the Celestron more with my refractors for imaging and viewing. Better images are also obtained when using these focal reducers at a reduction factor of 0.5x 0.8x, approximately. Celestrons FREE planetarium app is an astronomy suite that redefines how you experience the night sky. It's usually specified in millimeters. However, these will not impact optical performance. Read our 101 article or get in touch. Thank you so much for the informative article, I now understand better how to integrate my reducer into my system to get better performance. The new Lithium Phosphate (LiFePO4) battery chemistry has significant advantages over other battery chemistries, great for for those Astronomers on the go. 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. The internal surfaces are blackened and glare-threaded to provide the highest contrast. Reviews. They are also less expensive than many external focusers of similar build quality.

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