October 11, 2010 in Discussions - Scopes / Whole setups. However, the export of some items may be restricted outside the US due to size or manufacturer restrictions. Fumbling around in the dark, fine threads might be a problem. Opticstar F6.3 Focal Reducer / Corrector. Still not sure what is the right gear for you? The female end attaches to the rear cell of the telescope. In terms of reduction and correction - which are what reducer/correctors are supposed to do - both are superb. Free shipping $189.95 In both cases will end with a similar tfov. 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 . You need to be a member in order to leave a comment. These reducers can also be used for visual observing with SCT scopes with eyepieces with a field stop as large as 24-27mm. Perhaps not exactly- there will be some uncertainty because of manufacturing tolerances and so forth, but it will be close. The Antares f6.3 focal reducer screws directly to the visual-back thread of all popular SCTs and converts f10 instruments to f6.3. 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. 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. Weasner's Meade and Antares Focal Reducers Review The Reducer/Corrector can also be used for terrestrial digiscoping. It works fine but you should stick with 1.25 EPs; or can use 2" EPs without corrector. 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. However, some focal reducers can be used on other models of telescopes, but this is not always possible. In most cases, the easiest option is to choose the focal reducer made specifically for your telescope. The reduction factor MR can also be written in terms of d2 as: When the focal reducer is placed at the working distance, D, that is when d2=D, then the reduction factor MR is equal to the design reduction factor MRD: Equations (6) and (7) imply these important considerations: Most manufacturers do not publish the focal length of their focal reducers, so it is not usually possible to calculate the working distance and design reduction factor. However, the China 6.3 R/C has noticeable internal reflections that I haven't figured out yet. There will be no shipments on 3/1/2023, 3/2/2023, or 3/3/2023 (March 1st - March 3rd, 2023). 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. Our proprietary StarBright XLT optical coatings dramatically increase transmission, up to 97.4% on our Schmidt corrector lenses. Hello! To calculate how much back focus spacing you need to add, take the thickness of the filter and divide it by 3. A few people have reported issues with the male SCT thread diameter on this item being a bit larger than necessary. Rather than a direct side-by-side, I swapped the reducers so that I was using them on the exact same, well-collimated instrument. 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). For example, a 0.8x reducer placed at the working distance provides a reduction of (1 0.8) x 100 = 20%. 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. 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. No rainchecks will be issued for items out of stock at OPTcorp.com to match a competitor's price. Several functions may not work. With the Celestron Reducer/Corrector Lens, thats precisely what you get. Celestrons aplanatic EdgeHD optics revolutionized astroimaging. Stars had a tiny bit more sparkle and pop. This fully multi-coated lens provides maximum light transmission with near full-field illumination. Well done. The most popular accessories for your new telescope! Please let us know what topics you are interested in. 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. 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. Contiguous US Customers:All items we sell ship for free within the Contiguous US. 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. Wow, that is a very detailed discussion! Given the results of Test #1, I wanted to see if there was any truth to this assumption. Please Log in to save it permanently. Not noticed any optical problems. In some cases, focal reducers also act as field flatteners by correcting for field curvature and coma of the objective lens. Very helpful, thanks a lot for this article! All Rights Reserved. I think I remember hearing the reduction factor is slightly different, cant remember more or less reduction. This is very impressive performance given how hard this problem is to mitigate in general. He also holds a Ph.D. in engineering physics from McMaster University. OPT Product Number: AE-SCTFR specifications Warranty 2 Year Warranty Works as advertised! Completely stuck, completely frustrated. The Antares focal reducer comes in small box. Start here to find the perfect telescope for you! A focal reducer does just the opposite of a Barlow lens or focal extender. The nominal design reduction factor of these reducers is typically 0.5x. 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! Celestron is considered better in terms of QA, less likely to come with free dust, hair or fingerprint. 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). 2023 OPT Telescopes. Upgrading the Focuser of Your Schmidt-Cassegrain Telescope - Agena Astro Read our 101 article or get in touch. The working distance or required back focus, explained above, is usually specified and is far more important in practice. Celestron's EdgeHD reducers feature a custom 5 element optical design engineered to maintain the flat-field performance of our award-winning EdgeHD optical system. Once installed, you can add additional accessories like T-Adapters, 1.25 Visual Back, Star Diagonal, or Off-Axis Guider. Easy solution found a very tiny dab of super lube on the threads and all was well and quiet.. 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. 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. 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). 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. 0.5X focal reducer for Celestron, Meade, and Orion CCD imaging cameras Focal reducers for many SCTs and their flat-field equivalents usually have a back-focus distance of 105mm. 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. Specially-designed focal reducers are available for use with these telescopes. By using this site, you agree to our Terms of Use. In terms of reduction and correction which are what reducer/correctors are supposed to do both are superb. Sign up for a new account in our community. 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. So ab6110 is asking for a FR only without coma correction, there are a couple of brands who make special reducers for the ACF. 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. For the best experience on our site, be sure to turn on Javascript in your browser. It's usually specified from the base of the mounting threads on the reducer's housing, and this is the most practical way of providing this specification. 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. Oceanside Photo & Telescope wants our customers to shop with confidence knowing that you will always get the best deal available. Designed distancing using the reducer with a 1.25 visual back and 1.25 Televue mirror diagonal; If the reducer is placed elsewhere, at a position called the operating distance, the focal reduction factor will not be as advertised. So it provides a 0.63x design reduction factor when used with an f/10 SCT at the specified working distance. But in the Japan version I have never noticed any anomaly like the ghosting in the China R/C. This filter threads on to the rear cell of your Celestron or Meade SCT telescope. If you want to use them for visual - try maybe long focal length eyepieces rather than the reducer. 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. More important, its clear that the Antares is a reducer/corrector, just like the Celestron and not merely a reducer. 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. They never really recovered from selling a few 15 years back with element reversed. 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. Some refractors such the TeleVue Nagler-Petzval (NP), the Takahashi "FSQ", and the William Optics Redcat/WhiteCat 51 have inherently flat fields because of internal optical elements. In your opinion, is the Celestron is worth the added cost ($150 vs. $90)? ED stands for "extra-low dispersion," which refers to the composition and optical properties of the glass used for the lenses. Copyright 2021 Stargazers Lounge Quite interestingly it bears the very same engravings of the Meade 4000 r/c (including "series 4000") except for "MEADE". 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. Celestron & Antares f/6.3 Reducer/Corrector Shoot-out But the diameter of the image circle decreases by a factor of 0.63 to about 24mm. The C8 has no noticeable vignetting with a 32mm Plssl in the f/6.3 reducer. Possibly the design of the Antares was changed .. I was referring to the C6 to answer you specifically. Is there likely to be any differences in performance between using these on an 8 or something smaller like my 6SE? 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. 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. Again, to my surprise, there was absolutely no difference between the Celestron and Antares on any star. To test this, I used three set-ups: 1. The f/6.3 reducer is operating at f/5-f/5.5 with a 2" diagonal, depending on the back focus length of the diagonal. Therefore, a 55mm back focus with a filter that is 3mm thick added to the imaging train would become 56mm. I'm going with the Celestron. 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. 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. I wont bother with differences in packaging, caps, etc. Since 2008, Brian has taught astronomy to tens of thousands of stargazers through his websites OneMinuteAstronomer.com and CosmicPursuits.com. The price for an item/offer must be listed and valid at the time of match. That was fun. That is definitely a 2" eyepiece, but it is not a large or long focal length 2" eyepiece. This should not be the case if they have their purportedly different focal lengths. When using the diagonal, keep the field stops of the eyepieces under 20mm. Refractors, or SCTs with external focusers, may not have sufficient in-travel to reach focus in some configurations. 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 . 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. We have corrected # (iii) after equations 6 & 7. The problem with those SCT reducers is that they cause chromatic aberration and require refocusing when using parfocal RGB/other filters. 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. 3. Antares f/6.3 SCT Focal Reducer - Rother Valley Optics Ltd Celestron or Antares? Thanks Peter! Now, Celestron is using that same technology to allow star gazers to connect to the night sky and enhance their experience of the cosmos in fun and unique ways. Steve Each focal reducer has a fixed specification called the working distance or required back focus. Images in the Celestron tended to appear ever-so-slightly dimmer (maybe? Today, our world-class team of optical and electronic engineers continues to push the boundaries of technology. Unlike . Many reducers, such as the Celestron HD focal reducer mentioned above, and many focal reducers for apochromatic refractors, are meant to be used within a few millimeters (or less) of the specified working distance to achieve the best possible image results. 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. 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. 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. 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. which looks like the same one. (Note: Using the simple equations above, the focal length of this reducer can be estimated to be about 350mm). 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. 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. You attach the focal reducer to the rear port on a SCT and can keep it covered. Or, when the distance of the focal reducer to the focal plane of the objective d1 equals the focal length of the focal reducer FR, the reduction factor MR = 0.5x. . Such an image circle is still large enough to encompass the relatively large sensor of many deep-sky astronomy cameras. I have an 8SE, and am thinking about getting a focal reducer. Sign up for our newsletter to get exclusive deals, observing tips, and new product announcements. As a consequence, the standard f/6.3 and f/3.3 focal reducers for SCT scopes do not work. With the barrel 1.25 reducer won't focus, all I get is fuzzy snowballs. 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. External Focusers for Schmidt-Cassegrain Telescopes 3.1 The Basics of SCT Threads 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. Product Details. Sign up for our newsletter to get exclusive deals, observing tips, and new product announcements. Style: Better images are also obtained when using these focal reducers at a reduction factor of 0.5x 0.8x, approximately. Does anyone know if the Antares 4000 focal reducer is as good as the Celestron focal reducer. Maybe I got a lemon. Manish Panjwani has been an active amateur astronomer since before Halley's Comet last flew by our neighborhood. The naming convention of SCT focal reducers is a little confusing. Your mileage may vary. I have a made in Japan 6.3 R/C and a made in China 6.3 R/C. When placed in the focal plane in front of a camera or eyepiece, a focal reducer leads to a wider field of view and a brighter image of extended objects, which is important for reducing the exposure times when imaging faint extended objects like nebulae or galaxies. This telescope control software replaces the hand control and allows the user to remotely control their Celestron computerized telescope from their personal PC or laptop. 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. 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. The previous post shows the reducer on what appear to be two different refractors. The telescope side of the barrel is often threaded with an M48 x 0.75 thread for standard 2" astronomy filters. If used before or beyond the working distance, unwanted image distortion may result. I wonder whether, for example, Antares focal reducer for SCT belongs to the latter category. Regardless, the difference was miniscule and is more than adequate on both and exceeds a 8 or 6 SCTs baffle tube diameter. Focal Reducers - Complete Overview and Function - YouTube Brian Ventrudo is a writer, scientist, and astronomy educator. If you do so, you will achieve the design reduction factor. Some are available in 1.25" barrel format but with C threads. You can probably eke out 1.2 without noticing serious vignetting, which is a field stop of 31.5mm. Orders placed over the weekend will be shipped on the following Monday. How about for visual observers? 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). 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. Try & buy if you like - usual mates rates. 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. 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. Also, the focusers of most Newtonians do not have enough in-travel to accommodate a focal reducer. An f/6.3 reducer is designed to reduce the focal ratio of an f/10 SCT to f/6.3. WiFi technology encircles the globe in a web of connectivity, knowledge, and information. Hmmm . However, doesn't fit in the telescope and even if it did wouldn't work. 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). I wish there was. Reducer Lens .7x - EdgeHD 800 Learn More. The equations and argument in the Appendix of this article shows the relationship between the working distance and the reduction factor. 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. I don't know. 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"). Here, there was a subtle difference . A f/10 focal ratio now achieves a f/6.3, while an f/11 focal ratio now achieves a f/7. Planetarium software package which provides easy-to-understand explanations and impressive visuals of all kinds. That includes, for example, a 1.25" eyepiece with an apparent field of view of 68 and a focal length of 24mm (eg. There are also third-party vendors such as Hotech. 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. I really don't see any difference in the current crop except the "Meade" is usually the cheapest. 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! 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. 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. 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 Ive owned Celestron, Meade, and Antares models over the years at least a couple of each. I doubt there is any difference between the Antares and the Celestron except price. With both, using the same diagonal set-up, the exact same stars were visible at the very edge of the FOV. We reserve the right to verify a competitor's advertised price and the availability of the item. 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. Request stock alerts and we'll let you know when the item is back in stock. ED glass is specially formulated and contains rare-earth compounds that greatly reduce a visual defect called chromatic aberration. A former wireless communications consulting engineer and management consultant to various Fortune 500 companies, Manish started Agena AstroProducts in 2003. I have the Antares and have no complaints. Antares F/6.3 SCT Focal Reducer | OPT Telescopes I have had the Japan unit on the back of my C5 since 1994 or thereabouts. 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. Telescope Optics, Rutten and van Venrooij, Chapter 15, Willman-Bell (1988). If I had to guess, the difference is maybe 10-15 grams. Meade and Celestron both sell such SCT-T adapters with the correct optical length. Stars in the corner of the image frame are indistinguishable between the Antares and the Celestron. Some third-party vendors also make reducers for SCT scopes. InternetSales@optcorp.com. There are many different types of focal reducers and they all effect. This is a. Explore Scientific Keys to the Universe Sale. 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 designed reduction factor (0.5x in the case of the GSO reducer example above) should be considered a rule of thumb or approximate value in most cases, rather than a very precise number. The resultant reduction factor was measured to be 0.46x. Some faster refractors with a focal ratio of f/6, for example, only require field flatteners and not focal reducers. Edited by Tony Bonanno, 16 April 2021 - 06:44 PM. Just point the telescope at any three bright objectsstars, bright planets, or even the Moonand your telescope can orient itself with the night sky. 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. riklaunim Members 559 3,445 Location: Poland Posted October 11, 2010 They are reported as identical. It can also be used with any other small chip CCD camera having a 1.25" nosepiece, such as the Celestron NexImage, Meade DSI . Many focal reducers are meant to be used within a few millimeters of the specified working distance to achieve the best possible image results. 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. We have placed cookies on your device to help make this website better. But while the image gets brighter, the size of the image circle gets proportionately smaller. However, this also came at a cost, as the sky background in the Antares was slightly brighter. Things change but when I rebought I got an Antares and it seems about the same to me. More details are found in the Appendix of this article. Does anyone have any experience with the Celestron and Antares focal reducers? As another example,GSO makes focal reducers for their line of Ritchey-Chretien imaging telescopes. Reducer Lens .7x - EdgeHD 1100 - Celestron
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