I even lost track of which reducer I was using. I really don't see any difference in the current crop except the "Meade" is usually the cheapest. Observing the microscopic world has never been easier! The most significant mechanical variation, however, is the quality and precision of the threading. Sign up for a new account in our community. Optically, it consists of a four-element lens that is fully multi-coated for high contrast and resolution. As a result, the smaller tube may cut into the light cone and effectively reduce the working aperture of the telescope. As a consequence, the standard f/6.3 and f/3.3 focal reducers for SCT scopes do not work. 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. 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. 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. 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). 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. In many cases, the answer is yes, especially for electronically-assisted astronomy (EAA). Looking forward to the day when I can do a shoot-out between a Japan and China Celestron, just for kicks. Focal Reducer, 2", 0.7X. Due to the design, the Reducer/Corrector lens does diminish a small amount of field curvature common to all Schmidt Cassegrain telescopes but does not eliminate it. Most manufacturers provide this specification. Nebula Filters. 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. 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. ED stands for "extra-low dispersion," which refers to the composition and optical properties of the glass used for the lenses. With spring galaxy season here, I decided to pick up a couple more to compare in a head-to-head shoot out. Each focal reducer has a fixed specification called the working distance or required back focus. 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. Yet, the Antares still easily and fully threaded without any hitches. If you do so, you will achieve the design reduction factor. Opticstar F6.3 Focal Reducer / Corrector. 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. The threads were similar on the eyepiece end, but a bit smoother. Assuming you use the reducer with the stock 1.25" diagonal, it will operate at f/6.3. Because most modern Newtonians already have relatively fast focal ratios, these telescopes do not usually use focal reducers. Quite interestingly it bears the very same engravings of the Meade 4000 r/c (including "series 4000") except for "MEADE". Such an image circle is still large enough to encompass the relatively large sensor of many deep-sky astronomy cameras. We will be glad to help. InternetSales@optcorp.com, 800-483-6287 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. Performance wise what differences might there be using the reducer on a smaller scope. 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 focal reducer is made to attach to the rear cell of Schmidt-Cassegrain or Maksutov-Cassegrain telescopes. For example, many focal reducers designed for f/7 or f/8 ED refractors such as those from Tele Vue, William Optics, Sky-Watcher, and Meade are designed to have a working distance (or back focus) of 55mm. Torazz So Celestron buyers like Celestron, Meade buyers like the Meade and Antares buyer like the Antares. For visual use, this means you get lower power with the same eyepiece and a wider field of view. In the 1960s, Celestrons founder, Tom Johnson, created groundbreaking new telescopes never before seen on the consumer market. 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. Explore Scientific Keys to the Universe Sale. But in the Japan version I have never noticed any anomaly like the ghosting in the China R/C. The focus barely shifts between filters and I suspect any shifts I do get are down to the filters and changes in temp. 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. Best evidence would by obtained by using a camera and evaluating the image both by eye and with a computer analysis. More details are found in the Appendix of this article. Focal reducers for these relatively fast ED refractors are generally for imaging only, not for visual observation. Celestrons award-winning Nature DX binocular gets a major upgrade with the addition of ED objective lenses. Start here to find the perfect telescope for you! Figure 6 shows a 1.25" focal reducer from GSO configured with a ZWO ASI224MC camera. No difference. 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). 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. In most cases, the easiest option is to choose the focal reducer made specifically for your telescope. 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. Not noticed any optical problems. Please re-enable javascript to access full functionality. This filter threads on to the rear cell of your Celestron or Meade SCT telescope. Meade once made an f/3.3 focal reducer for SCT scopes. But the smaller image circle means there is a limit to the field stop of an eyepiece that can achieve an unvignetted image. We process your personal data as stated in our. I found both to be very good. High power views will provide flatter fields all the way to the edge, both visually and photographically. 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. Designed distancing using the reducer with a 1.25 visual back and 1.25 Televue mirror diagonal; We have tested our current batch and it works with Meade, Celestron, and Baader SCT accessories. Not one detectable iota of discernable difference. 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. The Antares f6.3 focal reducer screws directly to the visual-back thread of all popular SCTs and converts f10 instruments to f6.3. We will match any online price that we confirm as valid. But the diameter of the image circle decreases by a factor of 0.63 to about 24mm. There is a way to make subjective data more useful and that way is proper blind, or better still. I own both and concur heartily. In such cases, we will be happy to take the item back as per our standard return terms. How about for visual observers? All rights reserved. Focal reducers for many SCTs and their flat-field equivalents usually have a back-focus distance of 105mm. Again, these focal reducers are often provided by the telescope manufacturer. 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. If the reducer is placed elsewhere, at a position called the operating distance, the focal reduction factor will not be as advertised. 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. Newtonian reflectors will seldom be able to accommodate the in-focus travel demanded by focal reducers. 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. It works fine but you should stick with 1.25 EPs; or can use 2" EPs without corrector. Thanks Peter! This article explains the basics of how focal reducers work with an astronomy telescope. When using the diagonal, keep the field stops of the eyepieces under 20mm. So it provides a 0.63x design reduction factor when used with an f/10 SCT at the specified working distance. In your opinion, is the Celestron is worth the added cost ($150 vs. $90)? In some cases, focal reducers also act as field flatteners by correcting for field curvature and coma of the objective lens. For this shoot-out, I used a standard Celestron C8 with Starbright coatings. 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. 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). This focal reducer is made to attach to the rear cell of Schmidt-Cassegrain or Maksutov-Cassegrain telescopes. Thanks guys, appreciate the feedback. We do not price match competitors if they are out of stock. 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. October 11, 2010 in Discussions - Scopes / Whole setups. Melotte 15 - First Process in PixInsight (easy! These reducers can also be used for visual observing with SCT scopes with eyepieces with a field stop as large as 24-27mm. Meade and Celestron both sell such SCT-T adapters with the correct optical length. The easiest way to use a focal reducer is to make sure you place it at the specified working distance in front of your camera or eyepiece. By using this site, you agree to our Terms of Use. 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. Brian Ventrudo is a writer, scientist, and astronomy educator. 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. Antares or Celestron? 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. 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. However, some focal reducers can be used over a wider range of working distances, especially those with simpler optical design, and especially when used with cameras with smaller sensors. It can also be used with any other small chip CCD camera having a 1.25" nosepiece, such as the Celestron NexImage, Meade DSI . Focal reducers (and focal reducer/field flatteners combos) are usually used with two types of telescopes, refractors and compound telescopes such as Schmidt-Cassegrain or Ritchey-Chretien. 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. But in the end they both do pretty much the same thing and it sounds like any performance difference is subtle. I would not use the reducer with a 2" diagonal or eyepiece in the C6. This part is no longer in production, but it is sometimes available used and may be used with cameras with smaller sensors. Possibly the design of the Antares was changed .. Celestron Solar Safe filter technology is GUARANTEED SAFE for direct solar observation and has been independently tested by SAI Global Assurance Services. Just point the telescope at any three bright objectsstars, bright planets, or even the Moonand your telescope can orient itself with the night sky. In both cases will end with a similar tfov. But when not in the box or on the telescope, there is no cover for the other end. 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. 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. 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. WiFi technology encircles the globe in a web of connectivity, knowledge, and information. These reducers have a back focus (or design working distance) of 80mm. I've heard and read all kinds of things about the Antares being only a reducer and not a corrector, etc. F6.3 Focal reducer for F/10 or higher telescopes, 43mm aperture, 4-Element, Fully Multicoated. . With the barrel 1.25 reducer won't focus, all I get is fuzzy snowballs. if the illuminated field is 27mm wide without the reducer, it will be 27 x 0.63 = 17mm with it in place. 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. I was originally hoping to do this with a made in Japan Celestron, but ended up with a newer China version but thats probably better in the end since it is the version now available, with the Japan ones rarer and only available used. Field stop diameters are one of the specified specs of eyepieces. I was referring to the C6 to answer you specifically. The lens is housed in machined aluminum for are machined aluminum black anodized. If yes, what kind of focal reducers can I use? 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. One of the most important factors in a telescope is its transmissionthe percentage of light that reaches the focal plane. Again, to my surprise, there was absolutely no difference between the Celestron and Antares on any star. Will not focus with the stuff I have. Ive owned Celestron, Meade, and Antares models over the years at least a couple of each. The Buyer's Guide To Eyepieces at the top of the Eyepieces forum has a column for this spec. My application is mostly visual now, but I'm looking to do more astrophotography over time. The stock Celestron visualback is just under 2 long. Not a bit. 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. 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. 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! They only publish the value of D, the working distance (sometimes called the back focus distance) and the design reduction factor MRD. At a significantly lower price point, the Antares is a steal, and theres no need to upgrade to the Celestron if you already have one. 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. For Stephen Wilkerson: The ZWO ASI120MC-S does come with a wide angle lens, HOWEVER, it is NOT intended to used when you are using the ASI120 camera attached to your telescope. 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. Enter it during checkout! Article Agena AstroProducts, 2019. The stars at the edge could be worse or better. 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. 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. All Rights Reserved. Focal reducers for refractors are easy to use. Celestron is considered better in terms of QA, less likely to come with free dust, hair or fingerprint. 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. 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. As another example,GSO makes focal reducers for their line of Ritchey-Chretien imaging telescopes. . 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. Copyright 2021 Stargazers Lounge 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). So ab6110 is asking for a FR only without coma correction, there are a couple of brands who make special reducers for the ACF. 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. I'd favor the Japanese Celestron version over the others that are commercially available. There will be no shipments on 3/1/2023, 3/2/2023, or 3/3/2023 (March 1st - March 3rd, 2023). Take control of your telescope! That was fun. I've seen some older threads saying that the Celestron, Meade and Antares FRs are all the same and manufactured in the same factory. Never used one, but read the reviews here that suggest a coating problem. The new Lithium Phosphate (LiFePO4) battery chemistry has significant advantages over other battery chemistries, great for for those Astronomers on the go. There are many different types of focal reducers and they all effect. because they really dont matter. It is recommended for . 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. 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. Fumbling around in the dark, fine threads might be a problem. Wonder how they would stack up with a Japanese 6.3. I also used several eyepieces including the ES 24mm/68, 17.5mm and 12.5mm Morpheuses, and a 10.5mm Pentax XL. Based on Test 1 and Test 2, I think there is perhaps more validity to opposing statements here in these forums that the Antares and current China-made Celestron do, indeed, have exactly the same optics just with different housings and branding. You need to be a member in order to leave a comment. 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. Some coma is visible in the corners, but the image is quite good for EAA applications. 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. For example, a 0.8x reducer placed at the working distance provides a reduction of (1 0.8) x 100 = 20%. I only have the Celestron f/6.3. 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"). Reducer Lens .7x - EdgeHD 1100. If the reducer is placed closer to the eyepiece or camera than the distance D, the reduction factor decreases. control and Sky Viewer display makes selecting your target easy. Style: He also holds a Ph.D. in engineering physics from McMaster University. 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. Start Chat This focal reducer and field flattener consists of a four-element multicoated 40mm lens in a metal cell. CPWI has an extensive object database, employs PointXP mount modeling, and more. Equation 6 & 7 item two & three does not make sense, both say increase its reduction (one should say reduce its reduction?). 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. Since the focal length of the reducer, FR, is fixed, as d2 increases then MR decreases. 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. During check-out, you will be presented with several shipping choices and costs. I have an 8SE, and am thinking about getting a focal reducer. 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 . But nearly every observer who installs one of these devices is pleased with their performance. Celestron Focus Motor for SCT, EdgeHD & 8" RASA, Celestron C6 0.63 reducer/flattener back focus. ED glass is specially formulated and contains rare-earth compounds that greatly reduce a visual defect called chromatic aberration. If it's positioned further from the eyepiece or camera and closer to the telescope objective, the reduction factor increases. That includes, for example, a 1.25" eyepiece with an apparent field of view of 68 and a focal length of 24mm (eg. 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 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. Go behind the scenes with Celestrons product development team and learn more about our award-winning and patented innovations. By Most different was that the sky background was a little darker and more uniform, providing a tiny contrast boost for fainter objects. 2. 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. You can probably eke out 1.2 without noticing serious vignetting, which is a field stop of 31.5mm. Easy solution found a very tiny dab of super lube on the threads and all was well and quiet. This fully multi-coated lens provides maximum light transmission with near full-field illumination. The nominal design reduction factor of these reducers is typically 0.5x. Hi. Copyright 2003-2022 Agena AstroProducts. 1.2" in that scope is a field stop of 43mm at f/10 and 27mm at f/6.3. I have a made in Japan 6.3 R/C and a made in China 6.3 R/C. I wish there was. A f/10 focal ratio now achieves a f/6.3, while an f/11 focal ratio now achieves a f/7. I think that the FRs made in Japan in the day may have been better. 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. Your eyepieces are the first accessories you should learn to use with your telescope. During checkout, you may also be shown other optional faster shipping choices.US Customers in Hawaii and Alaska: Free shipping applies to almost all products. Benefits limited to hardware and conditions? 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. To test this, I used three set-ups: 1. They are reported as identical. Is there likely to be any differences in performance between using these on an 8 or something smaller like my 6SE? 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. With both, using the same diagonal set-up, the exact same stars were visible at the very edge of the FOV.