I own both and concur heartily. Reviews. I've only used it a few times but it looks good to me. 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. For me, I was looking for, and planning to keep, the one that yielded the greatest reduction. It was also a little brighter in the center of the field with subtle darkening in the outer 20% or so. control and Sky Viewer display makes selecting your target easy. Please note, orders placed after 10am on 2/28/2023 will be delayed. We will be glad to help. Our patented SkyAlign alignment technology makes setting up a computerized telescope simple, fast, and accurate. They both are great and I doubt my eyes could detect a difference in any one of them including the Japan version. My application is mostly visual now, but I'm looking to do more astrophotography over time. For the best experience on our site, be sure to turn on Javascript in your browser. 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. Another factor to consider: focal reducers also increase the angle at which light approaches the focal plane. 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. Regardless, the difference was miniscule and is more than adequate on both and exceeds a 8 or 6 SCTs baffle tube diameter. Sign up to get exclusive deals, observing tips, and new product announcements. And when used in some refractors, the field flattening is not as accurate as it is in the f/10 SCTs. Once installed, you can add additional accessories like T-Adapters, 1.25 Visual Back, Star Diagonal, or Off-Axis Guider. 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. Reducer Lens .7x - EdgeHD 925 Learn More. CPWI has an extensive object database, employs PointXP mount modeling, and more. Performance wise what differences might there be using the reducer on a smaller scope. This should not be the case if they have their purportedly different focal lengths. Copyright 2003-2022 Agena AstroProducts. Manish holds a Master's degree in Electrical Engineering from Virginia Tech and an MBA from the Kellogg School of Management at Northwestern University. Newtonian reflectors will seldom be able to accommodate the in-focus travel demanded by focal reducers. 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.. If I had to guess, the difference is maybe 10-15 grams. All Rights Reserved. This "speeds up" the optical train by reducing the focal length and magnification of the scope, requiring less time to integrate the same signal. Focal Reducer, 2", 0.7X. 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. Observing the microscopic world has never been easier! I use it on my C8 SCT with a 1000d, and it seems to do everything written on the tin. I would not use the reducer with a 2" diagonal or eyepiece in the C6. 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. 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. Reducer Lens .7x - EdgeHD 925 He received his first telescope at the age of 5 and completed his first university course in astronomy at the age of 12, eventually receiving a master's degree in the subject. The reducer is we might presume designed to correct to some as yet un-measured extent, the image of a standard SCT. Take control of your telescope! Style: 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"). More details are found in the Appendix of this article. The C8 has no noticeable vignetting with a 32mm Plssl in the f/6.3 reducer. That includes, for example, a 1.25" eyepiece with an apparent field of view of 68 and a focal length of 24mm (eg. It can also be used with any other small chip CCD camera having a 1.25" nosepiece, such as the Celestron NexImage, Meade DSI . 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. 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. In such cases, we will be happy to take the item back as per our standard return terms. Melotte 15 - First Process in PixInsight (easy! control and Sky Viewer display makes selecting your target easy. These RC reducers cannot be used with other types of telescopes. A f/10 focal ratio now achieves a f/6.3, while an f/11 focal ratio now achieves a f/7. Given the results of Test #1, I wanted to see if there was any truth to this assumption. Antares Click Lock Visual Back - posted in Cats & Casses: Here is the situation:I bought a Celestron CPC 1100 for visual use.Want to put on the scope simulteanously a6.3 focal reducer, filter wheel, and aneyepiece turret. 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. The problem with those SCT reducers is that they cause chromatic aberration and require refocusing when using parfocal RGB/other filters. Powered by Invision Community. . My experience is that CN sellers are way above those listing elsewhere. I have Hirsch focal reducer, which is yet another clone of the Celestron reducer. A longer effective focal length leads to higher magnification with a given eyepiece for visual observers. These reducers can also be used for visual observing with SCT scopes with eyepieces with a field stop as large as 24-27mm. There is a way to make subjective data more useful and that way is proper blind, or better still. Get ready for a night of astroimaging with your mount faster than previously thought possible with All-Star Polar Alignment. 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. 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. If you want to save a few buck watch the classifieds on CN. Yellow and orange members of open clusters stood out a bit more as the various stars displayed their individuality. Celestron Focus Motor for SCT, EdgeHD & 8" RASA, Celestron C6 0.63 reducer/flattener back focus. The Antares focal reducer comes in small box. No retailers currently carry this product. The most popular accessories for your new telescope! Please Log in to save it permanently. Increasing the operating distance, that is, moving a focal reducer away from the eyepiece or camera reduces its reduction factor, or conversely increases the amount of reduction. In practice, it's important to remember that you will rarely operate at the exact working distance and at the exact reduction factor that is specified. An eyepiece with a 27mm field stop yields a true field of 1.03 in the C6 at f/10. Perfect for the serious student, professional scientist and discriminating hobbyist. 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. 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. I also used several eyepieces including the ES 24mm/68, 17.5mm and 12.5mm Morpheuses, and a 10.5mm Pentax XL. Equation (4) shows the relationship between the distance d2 and the reduction factor MR. Several functions may not work. 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. Please let us know what topics you are interested in. 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. a Tele Vue Panoptic), or a Plossl eyepiece with an apparent field of view of 50 and a focal length of 32mm. This standard distance is a consequence of the design of DSLR cameras for which the distance of the sensor to the outer edge of the flanges is about 45 mm, while the T-ring that attaches to the flange for astrophotography is about 10mm thick. WiFi technology encircles the globe in a web of connectivity, knowledge, and information. 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. The new Lithium Phosphate (LiFePO4) battery chemistry has significant advantages over other battery chemistries, great for for those Astronomers on the go. Optically, it consists of a four-element lens that is fully multi-coated for high contrast and resolution. 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. The focal length and design working distance for this focal reducer were not available from the manufacturer. 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. For me the Antares was a little brighter and had the least scatter by a bit so the better coatings won. The more focal reduction, the further inward the focal plane will be. . 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. It might work but it does not tell us anything about how well or to what extent the product works to correct the field of an SCT. Go behind the scenes with Celestrons product development team and learn more about our award-winning and patented innovations. I found both to be very good. This is a. Meade once made an f/3.3 focal reducer for SCT scopes. 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. I would pay slightly more for the Japan produced version, just because Hirsch was not bad either but sold it since I had 2 already. Thks for that and its not for visual it for astrophotography. During check-out, you will be presented with several shipping choices and costs. Thanks for any advice or experience you could share. The reducer features fully coated optics in an anodized aluminum filter ring with an ergonomic rubber grip. So it provides a 0.63x design reduction factor when used with an f/10 SCT at the specified working distance. Assuming you use the reducer with the stock 1.25" diagonal, it will operate at f/6.3. For this test, I used a single configuration R/C, Click-lock, and 1.25 diagonal with the adapter. The lens has a knurled surface, providing a tremendous gripping surface for threading/unthreading. Possibly the design of the Antares was changed .. It's important to match the back focus to within a millimeter or two to get an optimal image, especially with cameras with larger sensors. It is recommended for . Have always disliked the crude, noisy SCT threads, but I get it. 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. It's easy! The key points are as follows: So just remember that a smaller distance (from the camera or eyepiece) means a lower amount of reduction (and vice versa). Fumbling around in the dark, fine threads might be a problem. Will not focus with the stuff I have. 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. 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. Because I have not heard any complaints about the made in China R/C. As another example,GSO makes focal reducers for their line of Ritchey-Chretien imaging telescopes. They are also less expensive than many external focusers of similar build quality. I've looked through one from Meade and first impression was that it was like the Celestron version. 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. As per the OP I still can't see any reason to buy the Celestron for significantly more $$$. Sign up to receive sale alerts, news about upcoming celestial events, and telescope tips from our experts! With spring galaxy season here, I decided to pick up a couple more to compare in a head-to-head shoot out. The Reducer/Corrector is easy to install by threading the unit onto the rear cell of your Schmidt-Cassegrain telescope (or the reducer plate of the C11 and C14). An image of about 24mm across, approximately, allows an observer to use a 1.25" eyepiece with a maximal field stop. That said any comparison reviews are helpful. Details: The item must be the identical item, brand name, size, weight, color, quantity and model number. You currently have javascript disabled. OPT Product Number: AE-SCTFR specifications Warranty 2 Year Warranty Works as advertised! I'm going with the Celestron. The female end attaches to the rear cell of the telescope. 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. Manish Panjwani has been an active amateur astronomer since before Halley's Comet last flew by our neighborhood. Any comments gratefully received. 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). Does anyone know if the Antares 4000 focal reducer is as good as the Celestron focal reducer. Telescope Optics, Rutten and van Venrooij, Chapter 15, Willman-Bell (1988). 2. Read our 101 article or get in touch. 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. Unlike . 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. These reducers have a back focus (or design working distance) of 80mm. Each focal reducer has a fixed specification called the working distance or required back focus. It's highly unlikely that they could be so precisely identical unless they were. I must admit, as well, that I no longer place a lot of stock in the notion that Chinese optics are inferior to Japanese or Taiwanese any longer, as manufacturing technology has really leveled the playing field today, with most Chinese optics being excellent. In some cases, focal reducers also act as field flatteners by correcting for field curvature and coma of the objective lens. At least these two units I tested make the answer - whatever. Oceanside Photo & Telescope wants our customers to shop with confidence knowing that you will always get the best deal available. Equation 6 & 7 item two & three does not make sense, both say increase its reduction (one should say reduce its reduction?). Fortunately, my neighbors are not out in their backyards at 11 pm, or they may have thought I was torturing a small mammal. They are reported as identical. Torazz If used before or beyond the working distance, unwanted image distortion may result, especially when using cameras with larger sensors. Many Ritchey-Chretien telescopes available today are made by GSO. For this shoot-out, I used a standard Celestron C8 with Starbright coatings. For imagers, the main purpose of a focal reducer is to increase the brightness of the image at the focal plane. 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. No difference. Your mileage may vary. It's an either/or proposition: reducer and 1.25", or 2", but not 2" and reducer. The previous post shows the reducer on what appear to be two different refractors. 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. As a result, the smaller tube may cut into the light cone and effectively reduce the working aperture of the telescope. Orders placed after 12:00 PM Pacific Time will be shipped the next business day. 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. 1.2" in that scope is a field stop of 43mm at f/10 and 27mm at f/6.3. 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). A few large telescopes and mounts are excluded from this free shipping offer. How about for visual observers? The stars at the edge could be worse or better. But is there a difference in quality between the Antares and the Celestron or Meade focal reducers? Orders placed over the weekend will be shipped on the following Monday. 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. Images in the Celestron tended to appear ever-so-slightly dimmer (maybe? In terms of reduction and correction which are what reducer/correctors are supposed to do both are superb. In many cases, the answer is yes, especially for electronically-assisted astronomy (EAA). Brian Ventrudo is a writer, scientist, and astronomy educator. 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. However, some focal reducers can be used on other models of telescopes, but this is not always possible. The Buyer's Guide To Eyepieces at the top of the Eyepieces forum has a column for this spec. * Not a Retail Store * 16313 Arthur StreetCerritos, CA 90703, USA. But when not in the box or on the telescope, there is no cover for the other end. Product Details. 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! For example, a 0.8x reducer placed at the working distance provides a reduction of (1 0.8) x 100 = 20%. Best evidence would by obtained by using a camera and evaluating the image both by eye and with a computer analysis. It also leads to larger (although fainter) images of extended objects like the Moon or planets for astrophotographers or visual observers. 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. Never noticed any anomalies with this unit. Images made with my ZWO 533 camera testing both show them to be essentially the same. If used with other f/ratios, the field flattening characteristic may be unpredictable. The faster f/ratio allows you to use slower film or shoot in lower light level situations and still properly expose your subject. 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. However, the export of some items may be restricted outside the US due to size or manufacturer restrictions. Even though they may have been slightly dimmer, galaxies were a bit easier to tease out of the urban light soup I deal with. The Reducer/Corrector can also be used for terrestrial digiscoping. In your opinion, is the Celestron is worth the added cost ($150 vs. $90)? Both exhibited consistent reduction, identical field flattening, and edge correction properties, and both were high quality optically and mechanically. It's usually specified in millimeters. It has only one cover, which surprised me. 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. They usually have a 2" barrel that slides into the telescope focuser. 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. 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. Nada. 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. Reducer - Corrector 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. 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 Some faster refractors with a focal ratio of f/6, for example, only require field flatteners and not focal reducers. 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. I had a Celestron, Antares and Hirsch for awhile and compared them over about a year. When you said, "in some cases" a focal reducer also works as a flattener/corrector, are you saying that not all focal reducers are flatteners/corrector? As a consequence, the standard f/6.3 and f/3.3 focal reducers for SCT scopes do not work. 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. I was referring to the C6 to answer you specifically. 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. Not noticed any optical problems. Looking forward to the day when I can do a shoot-out between a Japan and China Celestron, just for kicks. 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. So ab6110 is asking for a FR only without coma correction, there are a couple of brands who make special reducers for the ACF. The female end attaches to the rear cell of the telescope. Meade and Celestron both sell such SCT-T adapters with the correct optical length. No negative issues to report. The distances d1 andd2 can also be expressed in terms of the focal length of the focal reducer FR with the lens equation: Using Equation 2, Equation 1 can also be expressed in terms of d2: The focal reduction factor of the focal reducer depends on its focal length and its distance from the focal plane of the objective as shown by Equation 4: Again, for example, when the focal reducer is placed at the original focal plane of the objective, d1=0 and MR=1, which means there is no focal reduction. The reducer fits all Meade and Celestron . To test this, I used three set-ups: 1. You can probably eke out 1.2 without noticing serious vignetting, which is a field stop of 31.5mm. That was fun. There may have been an almost imperceptible difference, but the Antares and Celestron were producing precisely the same reduction. 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 . I focus using a moonlight electronic focuser and focusmax. InternetSales@optcorp.com. * Not a Retail Store * 16313 Arthur StreetCerritos, CA 90703, USA, Availability: Item has been discontinued by Agena and we no longer carry this item. Depending on the design of the telescope, they may require separate focal reducers if they require focal reducers at all. Please re-enable javascript to access full functionality. 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. This innovative software solves the time-consuming problem of trying to pinpoint the North Celestial Pole. We reserve the right to verify a competitor's advertised price and the availability of the item. Again, these focal reducers are often provided by the telescope manufacturer. For example, an 8" SCT without a focal reducer has an illuminated field of 38mm at 50% fall-off. No results, please adjust your filters. Many focal reducers for refractors have a working distance (or back focus distance) of 55mm. 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. I have/had both the Celestron (Japan) and Antares units. 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.