Many focal reducers are meant to be used within a few millimeters of the specified working distance to achieve the best possible image results. For imaging, a T-adapter is threaded to the camera side of the focal reducer, which in turns connects to the camera with the appropriate hardware. I've seen some older threads saying that the Celestron, Meade and Antares FRs are all the same and manufactured in the same factory. The lens that the ZWO comes with give a perfect wide angle image of what is in front of it. Regardless, the difference was miniscule and is more than adequate on both and exceeds a 8 or 6 SCTs baffle tube diameter. I have had the Japan unit on the back of my C5 since 1994 or thereabouts. Things change but when I rebought I got an Antares and it seems about the same to me. Generally, views through the Antares seemed a little more transparent and brighter. Field stop diameters are one of the specified specs of eyepieces. 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. Explore Scientific Keys to the Universe Sale, Antares f/6.3 Focal Reducer for Schmidt-Cassegrain Telescopes, Skip to the beginning of the images gallery. One problem with getting opinions is that most of use do not have both reducers or have never done a side by side comparison. Michael 1 ronin Members You currently have javascript disabled. No results, please adjust your filters. CEL-94245. The focus barely shifts between filters and I suspect any shifts I do get are down to the filters and changes in temp. Please Log in to save it permanently. Go behind the scenes with Celestrons product development team and learn more about our award-winning and patented innovations. Stars had a tiny bit more sparkle and pop. Perhaps not exactly- there will be some uncertainty because of manufacturing tolerances and so forth, but it will be close. However, even though the imprint on the item states "Reducer / Corrector" please note that his is a reducer only. Because I have not heard any complaints about the made in China R/C. Figure 2 shows the effective of a focal reducer on the light from a telescope objective. Article Agena AstroProducts, 2019. We reserve the right to verify a competitor's advertised price and the availability of the item. Designed distancing using the reducer with a 1.25 visual back and 1.25 Televue mirror diagonal; Description. The two samples I have PERFORM IDENTICALLY. Maybe I got a lemon. 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. And when used in some refractors, the field flattening is not as accurate as it is in the f/10 SCTs. 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. A little longer light path with a 2 Baader click-lock, low profile 1.25 adapter, and the 1.25 diagonal; Using this same example of an 8" SCT and a 0.63x reducer, a visual observer can also enjoy brighter images and a wider field of view. Meade does not make an equivalent line of focal reducers for the ACF scopes, although some models of Meade ACF are already at f/8, faster than the f/10 ratio of Celestron Edge HD scopes. In these equations: The combined focal length of the objective and focal reducer is given by Equation 1: For example, when d1=0, that is, the focal reducer is at the focal plane of the objective, Fcomb=Fo, so the focal reducer has no effect. It's usually specified in millimeters. The nominal design reduction factor of these reducers is typically 0.5x. Focal reducers for these relatively fast ED refractors are generally for imaging only, not for visual observation. Again, these focal reducers are often provided by the telescope manufacturer. . Specially-designed focal reducers are available for use with these telescopes. In this configuration, the 29.5mm camera nosepiece and a 6mm extension ring positions the reducer at a working distance of 53.5mm from the camera sensor, which is located 12.5mm inside the front edge of the camera. Reducer Lens .7x - EdgeHD 925 Learn More. All rights reserved. I own both and concur heartily. The lens has a knurled surface, providing a tremendous gripping surface for threading/unthreading. Thanks for pointing this out. 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. An f/6.3 reducer is designed to reduce the focal ratio of an f/10 SCT to f/6.3. But nearly every observer who installs one of these devices is pleased with their performance. I am new to these optic topics, and I want to ask you what happens with Masutov like SW or Celestron 4 or 7 inches. Just point the telescope at any three bright objectsstars, bright planets, or even the Moonand your telescope can orient itself with the night sky. But I am rusty, can you condense a bit for me please? if the illuminated field is 27mm wide without the reducer, it will be 27 x 0.63 = 17mm with it in place. This appendix summarizes how this works based on simple equations from the book Telescope Optics by Rutten and van Venrooij. Looking forward to the day when I can do a shoot-out between a Japan and China Celestron, just for kicks. This innovative software solves the time-consuming problem of trying to pinpoint the North Celestial Pole. Hi. You need to be a member in order to leave a comment. While most Barlow lenses and focal extenders work with most kinds of telescopes available to amateur astronomers, focal reducers are designed to work in a narrow range of focal ratios of a telescope objective. Is that distance D= Fo-d1=Fo-(d2/MR)? This also resulted in the clear aperture of the Antares being about 39-39.5mm, versus the Celestrons 41mm. Reviews. 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). There are also third-party vendors such as Hotech. 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. 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. Stock focusers in an SCT move the mirror of the scope to change the position of the focal plane, and they have sufficient travel to accommodate a focal reducer. Copyright 2003-2022 Agena AstroProducts. Celestron Solar Safe filter technology is GUARANTEED SAFE for direct solar observation and has been independently tested by SAI Global Assurance Services. Well done. A longer effective focal length leads to higher magnification with a given eyepiece for visual observers. And, the reality is that every F/6.3 RC out there Celestron, Hirsch, Astromania, etc., etc. Check out our 2022 telescope buying guide here! High power views will provide flatter fields all the way to the edge, both visually and photographically. How does it look thats what matters. You attach the focal reducer to the rear port on a SCT and can keep it covered. We have placed cookies on your device to help make this website better. These reducers have a back focus (or design working distance) of 80mm. Again, to my surprise, there was absolutely no difference between the Celestron and Antares on any star. I use it on my C8 SCT with a 1000d, and it seems to do everything written on the tin. Still not sure what is the right gear for you? An eyepiece with a 27mm field stop yields a true field of 1.03 in the C6 at f/10. The Celestron is both a corrector and focal reducer and the Antares is just a focal reducer. 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) Share Customers Also Purchased Description Optically, it consists of a four-element lens that is fully multi-coated for high contrast and resolution. 3. The EdgeHD .7x Focal Reducer Lens makes your EdgeHD 1100 one full F-Stop faster than f/10, reducing your exposure time by half to capture the same brightness of object . For the best experience on our site, be sure to turn on Javascript in your browser. As a consequence, the standard f/6.3 and f/3.3 focal reducers for SCT scopes do not work. Housings, threads, reduction, correction, blah, blah, blah. Celestrons FREE planetarium app is an astronomy suite that redefines how you experience the night sky. 1.2" in that scope is a field stop of 43mm at f/10 and 27mm at f/6.3. Meade once made an f/3.3 focal reducer for SCT scopes. Sign up for a new account in our community. Does anyone have any experience with the Celestron and Antares focal reducers? First, I wanted to compare the actual reduction provided by these competitors, as many threads here cite different ideal spacing from the reducer to eyepiece focal plane to achieve the correct f/6.3 result. They both are great and I doubt my eyes could detect a difference in any one of them including the Japan version. 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. This is very impressive performance given how hard this problem is to mitigate in general. 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 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. The Antares f/6.3 Focal Reducer for Schmidt-Cassegrain Telescopes is a low-price option for reducing the focal length of your Schmidt-Cassegrain telescope from f/10 to f/6.3. Both exhibited consistent reduction, identical field flattening, and edge correction properties, and both were high quality optically and mechanically. Thanks guys, appreciate the feedback. Unscrew that wide angle lens and put it away, then attach the ASI120 to the nose-piece that came with the camera and fit that into the eyepiece holder. 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 usually have a 2" barrel that slides into the telescope focuser. Scope size might influence choice as well, as a C6 might benefit from the Antares' transparency, while larger scopes might benefit from the Celestron's higher contrast. How about for visual observers? Thanks guys, I'm trying to get my ZWO ASI120MC-S to work with my 90mm Meade. Antares or Celestron? Since 2008, Brian has taught astronomy to tens of thousands of stargazers through his websites OneMinuteAstronomer.com and CosmicPursuits.com. If it's positioned further from the eyepiece or camera and closer to the telescope objective, the reduction factor increases. Newtonian reflectors will seldom be able to accommodate the in-focus travel demanded by focal reducers. Another factor to consider: focal reducers also increase the angle at which light approaches the focal plane. This should not be the case if they have their purportedly different focal lengths. Edited by bluewater, 05 September 2020 - 11:27 AM. 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. So, if you have a filter that is 3mm thick, you need to add 1mm of spacing to your imaging train to retain the correct back focus. It covers the basic optics and design specifications of a focal reducer, and goes through some practical factors to consider when selecting and using a focal reducer. Your eyepieces are the first accessories you should learn to use with your telescope. 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. You may need spacers or a T-adapter to ensure the correcting working distance. Dedicated focal reducers for refractors are intended primarily for imaging, not visual observation. The same illumination you have at the edge of a 27mm field, the C8 has at the edge of a 38mm field. Add a 0.63x reducer, and the brightness of extended objects increases by (1/0.63)2 = 2.5. No retailers currently carry this product. In some cases, focal reducers also act as field flatteners by correcting for field curvature and coma of the objective lens. For imagers using longer focal-length refractors and SCTs, especially when using smaller sensors that place less demand on the focal reducer, there are economical alternatives for focal reducers from manufacturers such as GSO, Agena, and Antares. A slight nod to the Antares for heft and higher transmission, but points to the Celestron for nice threads and better contrast. Most Feather Touch focusers cost between $300-$350. However, the China 6.3 R/C has noticeable internal reflections that I haven't figured out yet. The most commonly available focal reducers for SCTs are the f/6.3 reducers from Celestron and a similar f/6.3 focal reducer from Meade. With both, using the same diagonal set-up, the exact same stars were visible at the very edge of the FOV. That's partly because focal reducers correct for field curvature, which itself depends on the focal ratio and other optical design factors of the telescope. The reduction factor MR can also be written in terms of d2 as: When the focal reducer is placed at the working distance, D, that is when d2=D, then the reduction factor MR is equal to the design reduction factor MRD: Equations (6) and (7) imply these important considerations: Most manufacturers do not publish the focal length of their focal reducers, so it is not usually possible to calculate the working distance and design reduction factor. During check-out, you will be presented with several shipping choices and costs. 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. Is there likely to be any differences in performance between using these on an 8 or something smaller like my 6SE? Manish Panjwani has been an active amateur astronomer since before Halley's Comet last flew by our neighborhood. 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 click-lock with a 2 dielectric diagonal with a somewhat shorter light path, using both a 2 ES 28mm/68 and the same low-profile adapter with a 1.25 ES 24mm/68. It was also a little brighter in the center of the field with subtle darkening in the outer 20% or so. Focal Reducer, 2", 0.7X. I only have the Celestron f/6.3. The f/6.3 reducer is operating at f/5-f/5.5 with a 2" diagonal, depending on the back focus length of the diagonal. ), ASI Air Plus - Connected items are 'greyed out', Cost of ordering used equipment U.S. - Can can more than double figure, Tuthill Isostatic Mount and Star Trap Power Module. Today, our world-class team of optical and electronic engineers continues to push the boundaries of technology. InternetSales@optcorp.com, 800-483-6287 In the 1960s, Celestrons founder, Tom Johnson, created groundbreaking new telescopes never before seen on the consumer market. Depending on the design of the telescope, they may require separate focal reducers if they require focal reducers at all. 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. Anyway, when purchased my R/C the "original" Celestron unit was not readily available and was offered instead the one sold under the shop's own label (in my case Tecnosky, but I saw the same product offered under TS label). If you want to save a few buck watch the classifieds on CN. 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. But in the Japan version I have never noticed any anomaly like the ghosting in the China R/C. 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. 160K views 9 years ago This video is a complete overview of focal reducers and how they function applying to telescopes. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. I was referring to the C6 to answer you specifically. Sign up for our newsletter to get exclusive deals, observing tips, and new product announcements. What an enjoyable read and detailed comparison. Orders placed after 12:00 PM Pacific Time will be shipped the next business day. 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. Focal reducers for refractors are easy to use. . Please re-enable javascript to access full functionality. Easy solution found a very tiny dab of super lube on the threads and all was well and quiet.. The faster f/ratio allows you to use slower film or shoot in lower light level situations and still properly expose your subject. because they really dont matter. 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. So Celestron buyers like Celestron, Meade buyers like the Meade and Antares buyer like the Antares. With the Celestron Reducer/Corrector Lens, thats precisely what you get. Its a good thing I have the super lube handy or my neighbors wont be happy with me.come to think of it, Im sure the small mammals here wouldnt be thrilled either! I am a purely visual observer, so will evaluate for visual use only. Contiguous US Customers:All items we sell ship for free within the Contiguous US. But while the image gets brighter, the size of the image circle gets proportionately smaller. The reducer fits all Meade and Celestron . I've looked through one from Meade and first impression was that it was like the Celestron version. 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. The problem with those SCT reducers is that they cause chromatic aberration and require refocusing when using parfocal RGB/other filters. Since the focal plane of an eyepiece is rarely precisely known(except for some brands such as Baader Planetarium and Tele Vue), and because the nosepiece of an eyepiece is of a fixed length, the actual reduction factor will be close to, but not exactly at, its designed reduction factor. That means the base of the mounting threads of the focal reducer needs to be 55mm from the camera sensor to achieve the design reduction factor, which is usually 0.8x or 0.85x. I have Hirsch focal reducer, which is yet another clone of the Celestron reducer. But in the end they both do pretty much the same thing and it sounds like any performance difference is subtle. Since then, Agena has become one of the leading online retailers of telescopes and astronomical accessories worldwide. It has only one cover, which surprised me. With spring galaxy season here, I decided to pick up a couple more to compare in a head-to-head shoot out. USD $80.00. Nebula Filters. It must be in stock at the time of Price Match for us to make a guarantee. It also leads to larger (although fainter) images of extended objects like the Moon or planets for astrophotographers or visual observers. F6.3 Focal reducer for F/10 or higher telescopes, 43mm aperture, 4-Element, Fully Multicoated. Most reducers have a design reduction factor, MRD, that assumes the reducer is placed at a specific working distance, D, from the back surface of the focal reducer itself. I focus using a moonlight electronic focuser and focusmax. WiFi technology encircles the globe in a web of connectivity, knowledge, and information. 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. Your wishlist has been temporarily saved. Not a bit. For the best experience on our site, be sure to turn on Javascript in your browser. Such an image circle is still large enough to encompass the relatively large sensor of many deep-sky astronomy cameras. Hi - most interesting - may I ask .. the brighter guys - "if a camera sensor is too small for a n adaper, will a focal reduer allow me to get greater use from the camera? I wonder whether, for example, Antares focal reducer for SCT belongs to the latter category. Focal reducers also move the effective focal plane of the objective inward, that is, towards the objective (see Figure 1). 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. This is the simplest way to attach your ASI121 to your telescope. Performance wise what differences might there be using the reducer on a smaller scope. Any comments gratefully received. Reducer Lens .7x - EdgeHD 800 Learn More. 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. Perfect for the serious student, professional scientist and discriminating hobbyist. 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. 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. For both imaging and visual observing, these reducers also improve image sharpness at the edge of the field by correcting for coma and field curvature. However, because the field curvatures in refractors and SCTs vary a lot, I would predict unpredictable effects inre: field curvature. Our patented SkyAlign alignment technology makes setting up a computerized telescope simple, fast, and accurate. In your opinion, is the Celestron is worth the added cost ($150 vs. $90)? 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. For the best experience on our site, be sure to turn on Javascript in your browser. I doubt there is any difference between the Antares and the Celestron except price. Much to my surprise, swapping back and forth between the two correctors using all three diagonal configurations, I also could detect absolutely no change in reduction between the two reducers. Reducer Lens .7x - EdgeHD 925 Ive owned Celestron, Meade, and Antares models over the years at least a couple of each. ED glass is specially formulated and contains rare-earth compounds that greatly reduce a visual defect called chromatic aberration. More details are found in the Appendix of this article. 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. In terms of reduction and correction - which are what reducer/correctors are supposed to do - both are superb. The Antares is supposed to be pretty comparable. Fortunately, my neighbors are not out in their backyards at 11 pm, or they may have thought I was torturing a small mammal. and you will be fine. Sign up for OPT news, exclusive offers, and updates on the latest gear! He also holds a Ph.D. in engineering physics from McMaster University. I don't know. Celestron Reducer Lens .7x - EdgeHD 925 The EdgeHD .7x Focal Reducer Lens makes your EdgeHD 925 one full F-Stop faster than f/10, reducing your exposure time by half to capture the same brightness of object 5-element lens design Maintains similar. Benefits limited to hardware and conditions? There may have been an almost imperceptible difference, but the Antares and Celestron were producing precisely the same reduction. The review is a subjective visual impression, which is interesting but not best evidence. Start here to find the perfect telescope for you! Edited by Tony Bonanno, 16 April 2021 - 06:44 PM. I have an 8SE, and am thinking about getting a focal reducer. October 11, 2010 in Discussions - Scopes / Whole setups. I've only used it a few times but it looks good to me. In such cases, we will be happy to take the item back as per our standard return terms. Some third-party vendors also make reducers for SCT scopes. We only send interesting emails and will never sell your data. During a twenty-year scientific career, he developed laser systems to detect molecules found in interstellar space and planetary atmospheres, and leveraged his expertise to create laser technology for optical communications networks. Celestrons aplanatic EdgeHD optics revolutionized astroimaging. I use the same back spacing for both on a small 6" Celestron SCT. EclipSmart solar products feature Solar Safe filter technology providing the ultimate protection from harmful solar radiation, including both IR and UV light, and filters 99.999% of visible light. For Ritchey-Chretien telescopes such as those manufactured by GSO, there are also dedicated focal reducers with a reduction factor of 0.7x to 0.8x. Because of their distinct optical design, slower Schmidt-Cassegrain telescopes (SCT) with focal ratios of f/10 require a different design of focal reducer compared to refractors. . At least these two units I tested make the answer - whatever. There is a way to make subjective data more useful and that way is proper blind, or better still. The resultant reduction factor was measured to be 0.46x. But when not in the box or on the telescope, there is no cover for the other end. I've never found my 0.63 reducer causing CA when used with my SCT. The Best Dedicated Astronomy Cameras for Beginners, Astronomik OIII 12nm CCD Filter - T-Threads, Pegasus Astro Dual Motor Focus Controller, 10 Micron 12kg (26.45lbs) Stainless Steel Counterweight- GM 2000, I would like more information regarding stock availability dates. Read our 101 article or get in touch. Celestron is considered better in terms of QA, less likely to come with free dust, hair or fingerprint. 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. Figure 1 shows the relationship between the focal reduction factor MR and the position of the reducer in the optical path. There are many different types of focal reducers and they all effect. Equation 6 & 7 item two & three does not make sense, both say increase its reduction (one should say reduce its reduction?). Melotte 15 - First Process in PixInsight (easy! Thanks for any advice or experience you could share. The visual back must be removed first. Will not focus with the stuff I have. One focal reducer will not achieve optimum results with all types of telescopes, so there is no universal' focal reducer. 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. A useful thing to know is how far from the objective lens (for a refractor) is the focal reducer located. which looks like the same one. It features a standard male SCT thread (2" OD, 24 TPI) on one side and a standard SCT female thread on the other. More important, its clear that the Antares is a reducer/corrector, just like the Celestron and not merely a reducer.
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