Most focal reducers are designed to operate optimally at the working distance in the optical path to achieve their specified reduction factor, which is usually between 0.5x and 0.8x. The threads were similar on the eyepiece end, but a bit smoother. This is especially true when these reducers are used with cameras with smaller sensors with a dimension of about 1/4 to 1/3 the diameter of the reducer, and with telescopes with a focal ratio of f/7 or larger. Your eyepieces are the first accessories you should learn to use with your telescope. A longer effective focal length leads to higher magnification with a given eyepiece for visual observers. Unlike . Many focal reducers are meant to be used within a few millimeters of the specified working distance to achieve the best possible image results. If you place your camera at a different working distance, you will get a different reduction factor and perhaps unwanted distortion in the image. I don't know. More aggressive reduction, or using these reducers with larger sensors, will result in aberrations and distortions near the edge of the image. The more focal reduction, the further inward the focal plane will be. Again, swapping back and forth for a couple of hours on M44, M35, and several brighter stars, I examined the shape of specific stars near the edge of the field with both correctors. 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. Things change but when I rebought I got an Antares and it seems about the same to me. Add a 0.63x reducer, and the brightness of extended objects increases by (1/0.63)2 = 2.5. 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. We have tested our current batch and it works with Meade, Celestron, and Baader SCT accessories. 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. 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. Stars in the corner of the image frame are indistinguishable between the Antares and the Celestron. Learn more about extra solar planets imagery, 3D Star rendering, observation planning, telescope control, multiple-panel printing, and much more. If you want to use them for visual - try maybe long focal length eyepieces rather than the reducer. Fumbling around in the dark, fine threads might be a problem. It is not a corrector or flattener. The price for an item/offer must be listed and valid at the time of match. Overall, this reducer does a phenomenal job at preventing gradients due to internal reflections from the camera sensor back to the glass in the reducer, as I suffered with the Antares reducer. They only publish the value of D, the working distance (sometimes called the back focus distance) and the design reduction factor MRD. I've looked through one from Meade and first impression was that it was like the Celestron version. 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. However, it will not thread into William Optics accessories, and with GSO it is a hit or miss. Imaging - Focal Reducers and Flatteners - Page 1 - KW Telescope A wider field of view and a lower magnification is also useful, with some focal reducers and with some eyepieces, for visual observers with telescopes with long focal ratios. If the reducer is placed elsewhere, at a position called the operating distance, the focal reduction factor will not be as advertised. Antares F/6.3 SCT Focal Reducer | OPT Telescopes Equation 6 & 7 item two & three does not make sense, both say increase its reduction (one should say reduce its reduction?). For example, a 0.8x reducer placed at the working distance provides a reduction of (1 0.8) x 100 = 20%. 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. 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. WiFi technology encircles the globe in a web of connectivity, knowledge, and information. For me, I was looking for, and planning to keep, the one that yielded the greatest reduction. One problem with getting opinions is that most of use do not have both reducers or have never done a side by side comparison. This also resulted in the clear aperture of the Antares being about 39-39.5mm, versus the Celestrons 41mm. Weasner's Meade and Antares Focal Reducers Review How about for visual observers? The Antares f6.3 focal reducer screws directly to the visual-back thread of all popular SCTs and converts f10 instruments to f6.3. Refractors, or SCTs with external focusers, may not have sufficient in-travel to reach focus in some configurations. Does anyone know if the Antares 4000 focal reducer is as good as the Celestron focal reducer. Assuming you use the reducer with the stock 1.25" diagonal, it will operate at f/6.3. 3. 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. The resultant reduction factor was measured to be 0.46x. To calculate how much back focus spacing you need to add, take the thickness of the filter and divide it by 3. Most Feather Touch focusers cost between $300-$350. The Antares focal reducer comes in small box. control and Sky Viewer display makes selecting your target easy. If I had to guess, the difference is maybe 10-15 grams. 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. There is one difference though the Antares came with only one lens cap whereas the Celestron had a cap for both ends. Thanks Peter! When using the diagonal, keep the field stops of the eyepieces under 20mm. Most different was that the sky background was a little darker and more uniform, providing a tiny contrast boost for fainter objects. Great for home, classroom, or home-school use, this kit includes all the essential items youll need to begin exploring the wonders of the microscopic world. Start Chat Stars had a tiny bit more sparkle and pop. 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! It has only one cover, which surprised me. Perfect for the serious student, professional scientist and discriminating hobbyist. 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. A few large telescopes and mounts are excluded from this free shipping offer. Because I have not heard any complaints about the made in China R/C. 3. InternetSales@optcorp.com. Our patented SkyAlign alignment technology makes setting up a computerized telescope simple, fast, and accurate. 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. 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. Generally, views through the Antares seemed a little more transparent and brighter. Description. Planetarium software package which provides easy-to-understand explanations and impressive visuals of all kinds. Easy solution found a very tiny dab of super lube on the threads and all was well and quiet. Nada. A former wireless communications consulting engineer and management consultant to various Fortune 500 companies, Manish started Agena AstroProducts in 2003. Focal Reducer for SCT - ACF - Stargazers Lounge 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. 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. In terms of reduction and correction which are what reducer/correctors are supposed to do both are superb. The working distance of the GSO 0.5x focal reducer with 1.25" barrel and the GSO 0.5x focal reducer with 2" barrel is about 51mm to 53mm, approximately, from the middle of the metal cell that holds the lens. 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. An f/6.3 reducer is designed to reduce the focal ratio of an f/10 SCT to f/6.3. With the barrel 1.25 reducer won't focus, all I get is fuzzy snowballs. Yet, the Antares still easily and fully threaded without any hitches. 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. 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. Optically, it consists of a four-element lens that is fully multi-coated for high contrast and resolution. 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. I've heard and read all kinds of things about the Antares being only a reducer and not a corrector, etc. Figure 1 shows the relationship between the focal reduction factor MR and the position of the reducer in the optical path. 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. 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. As a consequence, the standard f/6.3 and f/3.3 focal reducers for SCT scopes do not work. 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. Images made with my ZWO 533 camera testing both show them to be essentially the same. Best evidence would by obtained by using a camera and evaluating the image both by eye and with a computer analysis. Go behind the scenes with Celestrons product development team and learn more about our award-winning and patented innovations. 1.2" in that scope is a field stop of 43mm at f/10 and 27mm at f/6.3. Back-Focus 101: DSLR Cameras & the Celestron f/6.3 Reducer - YouTube I only have the Celestron f/6.3. It was also a little brighter in the center of the field with subtle darkening in the outer 20% or so. Performance wise what differences might there be using the reducer on a smaller scope. Explicitly designed for Celestron Schmidt-Cassegrain telescopes, this unique lens reduces your telescopes focal length and f/ ratio by 37%, turning your long focal length telescope into a fast, short focal length instrument. Check out our 2022 telescope buying guide here! I wish there was. 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 lens is housed in machined aluminum for are machined aluminum black anodized. Not noticed any optical problems. For these items, please contact us to obtain a shipping quote before you check out using the online shopping cart.International Customers:Free shipping does not apply to international orders. However, some focal reducers can be used on other models of telescopes, but this is not always possible. The Antares is supposed to be pretty comparable. 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. Blue Fireball M42 T/T2 Thread Camera Adapter for Prime Focus Photography - 2" # P-06, Celestron T-Ring for Canon EOS Camera # 93419, GSO 2" Crayford Focuser for SCTs - Dual Speed, Length of male SCT thread = 5mm (0.2") but this is preceded by an unthreaded part on the eyepiece side making the total length = 8.8mm (0.35"), Length of female SCT thread = 7.5mm (0.3"). When the camera sensor is placed at this distance, the reduction factor of these reducers is 0.75x. In such cases, we will be happy to take the item back as per our standard return terms. They usually have a 2" barrel that slides into the telescope focuser. Manish holds a Master's degree in Electrical Engineering from Virginia Tech and an MBA from the Kellogg School of Management at Northwestern University. They both are great and I doubt my eyes could detect a difference in any one of them including the Japan version. Wonder how they would stack up with a Japanese 6.3. Celestron Nexstar+ 127 SLT, several budget plossl eyepieces, Celestron 8-24mm zoom EP and a 12.5mm illuminated double reticle EP, Svbony SV205 camera w/.5 focal reducer, Celestron SkyMaster 20x80 binos on a 40 yr old QuickSet PanHead tripod, Stellarium, Sharpcap and ManyCam on my laptop, SkyView and Nightshift on my phone and a dandy little $9 . 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. In this case, an additional T-adapter (with an optical length of 50mm) is needed to get the spacing correct for a DSLR or other camera with a 55mm back focus. You currently have javascript disabled. This would tell us exactly how well aberrations are corrected. 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. All Rights Reserved. * Not a Retail Store * 16313 Arthur StreetCerritos, CA 90703, USA, Availability: Item has been discontinued by Agena and we no longer carry this item. Telescope Focal Reducers & Correctors - High Point Scientific There is a way to make subjective data more useful and that way is proper blind, or better still. and you will be fine. ), 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. The working distance or required back focus, explained above, is usually specified and is far more important in practice. An eyepiece with a 27mm field stop yields a true field of 1.03 in the C6 at f/10. Depending on the design of the telescope, they may require separate focal reducers if they require focal reducers at all. 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 . Can you tell me about the use of reducers in Maksutov-Cassegrain telescopes? 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. Some coma is visible in the corners, but the image is quite good for EAA applications. Explore Scientific - Keys to the Universe Sale. CPWI has an extensive object database, employs PointXP mount modeling, and more. Looking forward to the day when I can do a shoot-out between a Japan and China Celestron, just for kicks. In terms of reduction and correction - which are what reducer/correctors are supposed to do - both are superb. However, even though the imprint on the item states "Reducer / Corrector" please note that his is a reducer only. But nearly every observer who installs one of these devices is pleased with their performance. None of this was offensive, nor did it interfere with views in any significant way. In some cases, focal reducers also act as field flatteners by correcting for field curvature and coma of the objective lens. 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. The nominal design reduction factor of these reducers is typically 0.5x. As mentioned in Section 2.3, the reduction factor for these focal reducers can be varied by adding spacers to move the reducer further from the camera sensor or eyepiece. An image of about 24mm across, approximately, allows an observer to use a 1.25" eyepiece with a maximal field stop. 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). 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. Some manufacturers will specify the working distance from the middle of the rear lens surface, and this number must then be converted into a practical working distance number by subtracting the amount by which the rear lens surface is recessed in its housing. Your price: $579.00. In this case, d2 = FR/2, which means the back of the focal reducer is located at a distance FR/2 from the camera or eyepiece. Sign up for our newsletter to get exclusive deals, observing tips, and new product announcements. This part is no longer in production, but it is sometimes available used and may be used with cameras with smaller sensors. For this test, I used a single configuration R/C, Click-lock, and 1.25 diagonal with the adapter. Antares Click Lock Visual Back - Cats & Casses - Cloudy Nights 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. The brightness, shape, and distortion of specific stars in the exact same position at the edge of the field was precisely identical in both reducers. It also leads to larger (although fainter) images of extended objects like the Moon or planets for astrophotographers or visual observers. Have always disliked the crude, noisy SCT threads, but I get it. Reducer Lens .7x - EdgeHD 925 Learn More. Newtonian reflectors will seldom be able to accommodate the in-focus travel demanded by focal reducers. Focal reducers for many SCTs and their flat-field equivalents usually have a back-focus distance of 105mm. My application is mostly visual now, but I'm looking to do more astrophotography over time. For example, the focal reducer for an 8-inch Celestron EdgeHD telescope has a design reduction factor of 0.7x and a specified working distance (or back focus) of 105mm. 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. However, this also came at a cost, as the sky background in the Antares was slightly brighter. The female end attaches to the rear cell of the telescope. How to Set the Correct Back Focus for Your Telescope (Guide) These reducers can also be used for visual observing with SCT scopes with eyepieces with a field stop as large as 24-27mm. They never really recovered from selling a few 15 years back with element reversed. 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. However, I noticed immediately that the Antares had a bit more of an heft to it, giving it a solid feel the Celestron didnt possess. However, manufacturers virtually never provide this specification. The faster f/ratio allows you to use slower film or shoot in lower light level situations and still properly expose your subject. CEL-94245. In every configuration, there were essentially parfocal, requiring only a tiny fine focus adjustment when changing correctors. Enter it during checkout! The naming convention of SCT focal reducers is a little confusing. 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. 2. No results, please adjust your filters. 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. No idea what the issue is. For the best experience on our site, be sure to turn on Javascript in your browser. Regardless, the difference was miniscule and is more than adequate on both and exceeds a 8 or 6 SCTs baffle tube diameter. For the best experience on our site, be sure to turn on Javascript in your browser. 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. Melotte 15 - First Process in PixInsight (easy! The equations in the Appendix show how this all works. F 6.3 focal reducer/corrector. - Discussions - Stargazers Lounge By 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. He tested this on an 8 Celestron , I have a Celestron 6SE. USD $80.00. We only send interesting emails and will never sell your data. Thanks guys, I'm trying to get my ZWO ASI120MC-S to work with my 90mm Meade. 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. This "speeds up" the optical train by reducing the focal length and magnification of the scope, requiring less time to integrate the same signal. But in the Japan version I have never noticed any anomaly like the ghosting in the China R/C. Clearly cost is a big factor for satisfied users. Copyright 2021 Stargazers Lounge That was fun. 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. 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. To test this, I used three set-ups: 1. (Note: Using the simple equations above, the focal length of this reducer can be estimated to be about 350mm). Take control of your telescope! Can you help me? It's usually specified in millimeters. The reducer features fully coated optics in an anodized aluminum filter ring with an ergonomic rubber grip. 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. The reducer is we might presume designed to correct to some as yet un-measured extent, the image of a standard SCT. 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. No difference. 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. These reducers can also be used for visual observing with SCT scopes with eyepieces with a field stop as large as 24-27mm. Powered by Invision Community. Again, these focal reducers are often provided by the telescope manufacturer. Also read the reviews here, including those at 4 stars. I am a purely visual observer, so will evaluate for visual use only. It seems right to put some distance between the camera and the focal reducer, right? More details are found in the Appendix of this article. There are many different types of focal reducers and they all effect. For me the Antares was a little brighter and had the least scatter by a bit so the better coatings won. Unleash the full pointing accuracy of your Celestron computerized telescope with a specialized telescope control software suite. I had a Celestron, Antares and Hirsch for awhile and compared them over about a year. This filter threads on to the rear cell of your Celestron or Meade SCT telescope. Reducer - Corrector Learn More. Thank you so much for the informative article, I now understand better how to integrate my reducer into my system to get better performance. 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. 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. 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. . Celestron Solar Safe filter technology is GUARANTEED SAFE for direct solar observation and has been independently tested by SAI Global Assurance Services. Place the plastic covers on the lens when not in use to reduce the dust collection. The focal length of a focal reducer is usually measured from the rear lens surface of the reducer (and not the reducer's housing). 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. control and Sky Viewer display makes selecting your target easy. JavaScript seems to be disabled in your browser. riklaunim Members 559 3,445 Location: Poland Posted October 11, 2010 They are reported as identical. 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. No small animals were harmed in making these observations. Maybe I got a lemon. Using an eyepiece with a 27mm field stop with the reducer will illuminate the edge the same as using an eyepieces with a 42.9mm field stop without it. One of the most important factors in a telescope is its transmissionthe percentage of light that reaches the focal plane. Read our guide! For imagers, the main purpose of a focal reducer is to increase the brightness of the image at the focal plane. 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. No retailers currently carry this product.