The design reduction factor of a focal reducer is the relative amount by which the effective focal length of the telescope is reduced when the focal reducer is used at its specified working distance or back focus. They are reported as identical. 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. The reducer fits all Meade and Celestron . If you want to use them for visual - try maybe long focal length eyepieces rather than the reducer. Using one on such a scope would make demands on the eyepiece design and increase the exit pupil to an extent that focal reduction on fast Newts is not practical. Sign up for OPT news, exclusive offers, and updates on the latest gear! Years ago, I bought the Antares version, and moved over to the Celestron. Therefore, a 55mm back focus with a filter that is 3mm thick added to the imaging train would become 56mm. 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. 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. The naming convention of SCT focal reducers is a little confusing. He also holds a Ph.D. in engineering physics from McMaster University. Optically, it consists of a four-element lens that is fully multi-coated for high contrast and resolution. ), but stars seemed a bit tighter and their colors were richer and more dramatic. Like you, I am primarily visually observing but I have everything together now that so I am going to start experimenting with photography so we'll see how it does there. The Antares focal reducer comes in small box. Perhaps not exactly- there will be some uncertainty because of manufacturing tolerances and so forth, but it will be close. The stars at the edge could be worse or better. Getting the proper back-focus for your imaging camera is a vital step in getting the best data possible out of your telescope imaging/research rig. All Rights Reserved. Like many of us with SCTs, I have bought and sold a number of f/6.3 reducer/correctors over the years, and I have always been curious how they really stack up to each other. Manish holds a Master's degree in Electrical Engineering from Virginia Tech and an MBA from the Kellogg School of Management at Northwestern University. Completely stuck, completely frustrated. All rights reserved. The equations in the Appendix show how this all works. It's an either/or proposition: reducer and 1.25", or 2", but not 2" and reducer. Does anyone know if the Antares 4000 focal reducer is as good as the Celestron focal reducer. I even lost track of which reducer I was using. The visual back must be removed first. Figure 6 shows a 1.25" focal reducer from GSO configured with a ZWO ASI224MC camera. 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. 160K views 9 years ago This video is a complete overview of focal reducers and how they function applying to telescopes. None of this was offensive, nor did it interfere with views in any significant way. I've seen some older threads saying that the Celestron, Meade and Antares FRs are all the same and manufactured in the same factory. StevieDvd Members 1,182 1,812 Location: Stevenage, UK Posted March 9, 2021 (edited) Don't know but your welcome to try out my Meade 6.3 sct reducer next time you are passing. Read our guide! However, some focal reducers can be used on other models of telescopes, but this is not always possible. . They only publish the value of D, the working distance (sometimes called the back focus distance) and the design reduction factor MRD. 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 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. Try & buy if you like - usual mates rates. Many Ritchey-Chretien telescopes available today are made by GSO. 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. 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. 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. 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. I have a Raspberry HQ camera, a Sony TV Zoom 12.5-75mm f1.8 and a Astromania 1,25" 0.5x focal reducer. Performance wise what differences might there be using the reducer on a smaller scope. 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. However, even though the imprint on the item states "Reducer / Corrector" please note that his is a reducer only. Bear in mind you can't squeeze blood out of a turnip, i.e. The reducer features fully coated optics in an anodized aluminum filter ring with an ergonomic rubber grip. Some are available in 1.25" barrel format but with C threads. The faster f/ratio allows you to use slower film or shoot in lower light level situations and still properly expose your subject. Request stock alerts and we'll let you know when the item is back in stock. As a real-world example plot showing the above relationships, let's look at the 1.25" GSO focal reducer that provides a design reduction factor of 0.5x. I wish there was. Add a 0.63x reducer, and the brightness of extended objects increases by (1/0.63)2 = 2.5. Each focal reducer has a fixed specification called the working distance or required back focus. An f/6.3 reducer is designed to reduce the focal ratio of an f/10 SCT to f/6.3. 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? The lens has a knurled surface, providing a tremendous gripping surface for threading/unthreading. It has only one cover, which surprised me. But in the Japan version I have never noticed any anomaly like the ghosting in the China R/C. For me the Antares was a little brighter and had the least scatter by a bit so the better coatings won. We process your personal data as stated in our. Focus misses by about 1 turnof the focus knob.Here is my solution:Buy a shorter 1.25 visual back for my scope. First, let's have a look at some key optical parameters are needed to understand focal reducers. If used before or beyond the working distance, unwanted image distortion may result. That includes, for example, a 1.25" eyepiece with an apparent field of view of 68 and a focal length of 24mm (eg. 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. I wont bother with differences in packaging, caps, etc. 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 Celestron is both a corrector and focal reducer and the Antares is just a focal reducer. The resultant reduction factor was measured to be 0.46x. 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. Nowadays I tend to use the Celestron more with my refractors for imaging and viewing. F6.3 Focal reducer for F/10 or higher telescopes, 43mm aperture, 4-Element, Fully Multicoated. As a consequence, the standard f/6.3 and f/3.3 focal reducers for SCT scopes do not work. 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. But is there a difference in quality between the Antares and the Celestron or Meade focal reducers? 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. For example, a 0.8x reducer placed at the working distance provides a reduction of (1 0.8) x 100 = 20%. 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. If you want to save a few buck watch the classifieds on CN. How does it look thats what matters. The price for an item/offer must be listed and valid at the time of match. Reducer - Corrector This article explains the basics of how focal reducers work with an astronomy telescope. 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. 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 only have the Celestron f/6.3. It's usually specified in millimeters. In both cases will end with a similar tfov. Reducer Lens .7x - EdgeHD 1100 Learn More. High power views will provide flatter fields all the way to the edge, both visually and photographically. 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"). I'm going with the Celestron. 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 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. Because I have not heard any complaints about the made in China R/C. Copyright 2003-2022 Agena AstroProducts. But in the end they both do pretty much the same thing and it sounds like any performance difference is subtle. Check out our 2022 telescope buying guide here! 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. 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 . The Antares f6.3 focal reducer screws directly to the visual-back thread of all popular SCTs and converts f10 instruments to f6.3. As a result, the smaller tube may cut into the light cone and effectively reduce the working aperture of the telescope. Sharpness is essentially the same. 2. 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. riklaunim Members 559 3,445 Location: Poland Posted October 11, 2010 They are reported as identical. A f/10 focal ratio now achieves a f/6.3, while an f/11 focal ratio now achieves a f/7. Once focused it's pretty good. Never used one, but read the reviews here that suggest a coating problem. We only send interesting emails and will never sell your data. The Antares is supposed to be pretty comparable. I have/had both the Celestron (Japan) and Antares units. Figure 7 shows an example of an image of the Dumbbell Nebula taken with a 1.25" GSO focal reducer at a reduction factor of 0.63x with an 85mm f/7 refractor and a QHY5III-290M camera with a sensor with a 6.4mm diagonal. It also leads to larger (although fainter) images of extended objects like the Moon or planets for astrophotographers or visual observers. The previous post shows the reducer on what appear to be two different refractors. We have corrected # (iii) after equations 6 & 7. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. For visual use, this means you get lower power with the same eyepiece and a wider field of view. They provide 0.75x focal reducers for these telescopes that takes an f/8 instrument down to f/6. Never noticed any anomalies with this unit. Housings, threads, reduction, correction, blah, blah, blah. No idea what the issue is. CPWI has an extensive object database, employs PointXP mount modeling, and more. The Celestron f/6.3 is ~150 compared to the Antares at ~70. The stock Celestron visualback is just under 2 long. Unleash the full pointing accuracy of your Celestron computerized telescope with a specialized telescope control software suite. Today, our world-class team of optical and electronic engineers continues to push the boundaries of technology. With the barrel 1.25 reducer won't focus, all I get is fuzzy snowballs. It was used strictly for imaging, not visual observing. Thanks guys, I'm trying to get my ZWO ASI120MC-S to work with my 90mm Meade. 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. Reducer Lens .7x - EdgeHD 800 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. Take control of your telescope! Can these economical focal reducers from GSO and other vendors result in good images? 800-483-6287 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. 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. Hi. 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. Sign up for a new account in our community. 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. 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. * Not a Retail Store * 16313 Arthur StreetCerritos, CA 90703, USA. Obviously bright objects like Jupiter or The Moon show the reflections. Reducer Lens .7x - EdgeHD 1400 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. control and Sky Viewer display makes selecting your target easy. How about for visual observers? Generally, views through the Antares seemed a little more transparent and brighter. The problem with those SCT reducers is that they cause chromatic aberration and require refocusing when using parfocal RGB/other filters. All rights reserved. You attach the focal reducer to the rear port on a SCT and can keep it covered. The most popular accessories for your new telescope! Most Feather Touch focusers cost between $300-$350. Several functions may not work. 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. Will not focus with the stuff I have. 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. Celestrons award-winning Nature DX binocular gets a major upgrade with the addition of ED objective lenses. The amount of reduction is simply the percentage by which a reducer shortens the effective focal length of a telescope and is calculated as (1 Reduction Factor) x 100%. Torazz 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. A focal reducer does just the opposite of a Barlow lens or focal extender. The working distance or required back focus, explained above, is usually specified and is far more important in practice. This innovative software solves the time-consuming problem of trying to pinpoint the North Celestial Pole. Many focal reducers are meant to be used within a few millimeters of the specified working distance to achieve the best possible image results. Powered by Invision Community. During check-out, you will be presented with several shipping choices and costs. The Buyer's Guide To Eyepieces at the top of the Eyepieces forum has a column for this spec. This superb fully multi-coated multi-element focal reducer takes advantage of the latest computer aided design techniques to achieve the highest standards of performance set by the brand leaders at a fraction of the cost. Wonder how they would stack up with a Japanese 6.3. SKU: CEL-94245. All additional accessories mount onto the exterior/male threads. A few large telescopes and mounts are excluded from this free shipping offer.