I've seen some older threads saying that the Celestron, Meade and Antares FRs are all the same and manufactured in the same factory. Possibly the design of the Antares was changed .. 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. Yellow and orange members of open clusters stood out a bit more as the various stars displayed their individuality. Upon close inspection, it was clear that the housing of Antares assembled in Canada version was a little more substantial than the Celestron. In these equations: The combined focal length of the objective and focal reducer is given by Equation 1: For example, when d1=0, that is, the focal reducer is at the focal plane of the objective, Fcomb=Fo, so the focal reducer has no effect. This appendix summarizes how this works based on simple equations from the book Telescope Optics by Rutten and van Venrooij. None of this was offensive, nor did it interfere with views in any significant way. We have corrected # (iii) after equations 6 & 7. if the illuminated field is 27mm wide without the reducer, it will be 27 x 0.63 = 17mm with it in place. For imagers, the main purpose of a focal reducer is to increase the brightness of the image at the focal plane. Benefits limited to hardware and conditions? I'm going with the Celestron. Because most modern Newtonians already have relatively fast focal ratios, these telescopes do not usually use focal reducers. Since 2008, Brian has taught astronomy to tens of thousands of stargazers through his websites OneMinuteAstronomer.com and CosmicPursuits.com. 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. This should not be the case if they have their purportedly different focal lengths. The female end attaches to the rear cell of the telescope. I think that the FRs made in Japan in the day may have been better. I use it on my C8 SCT with a 1000d, and it seems to do everything written on the tin. 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. Since then, Agena has become one of the leading online retailers of telescopes and astronomical accessories worldwide. I wont bother with differences in packaging, caps, etc. 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). Reducer - Corrector This factor is designated by a power that is less than 1, and it usually lies between 0.5x or 0.8x. The click-lock with a 2 dielectric diagonal with a somewhat shorter light path, using both a 2 ES 28mm/68 and the same low-profile adapter with a 1.25 ES 24mm/68. If you want to use them for visual - try maybe long focal length eyepieces rather than the reducer. Is there likely to be any differences in performance between using these on an 8 or something smaller like my 6SE? By using this site, you agree to our Terms of Use. No retailers currently carry this product. Great report and verifies what I had thought all along, Fortunately, my neighbors are not out in their backyards at 11 pm, or they may have thought I was torturing a small mammal. 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. This focal reducer is made to attach to the rear cell of Schmidt-Cassegrain or Maksutov-Cassegrain telescopes. 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. It is recommended for . 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. Some third-party vendors also make reducers for SCT scopes. Download the Celestron PWI Telescope Control Software. This is the distance at which the reducer must be placed in front of the eyepiece or camera focal plane in order to operate at the design reduction factor. Manish Panjwani has been an active amateur astronomer since before Halley's Comet last flew by our neighborhood. A f/10 focal ratio now achieves a f/6.3, while an f/11 focal ratio now achieves a f/7. I have Hirsch focal reducer, which is yet another clone of the Celestron reducer. 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. Not a bit. Scope size might influence choice as well, as a C6 might benefit from the Antares' transparency, while larger scopes might benefit from the Celestron's higher contrast. He 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. Read our 101 article or get in touch. Not noticed any optical problems. Who cares? They provide 0.75x focal reducers for these telescopes that takes an f/8 instrument down to f/6. 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. My experience is that CN sellers are way above those listing elsewhere. 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. 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. which looks like the same one. I even lost track of which reducer I was using. My Celestron was made in China and the Antares in Canada. Enter it during checkout! There will be no shipments on 3/1/2023, 3/2/2023, or 3/3/2023 (March 1st - March 3rd, 2023). 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. Completely stuck, completely frustrated. You don't need to follow these equations to use a focal reducer, but they do show how the reduction factor changes with the placement of the reducer. The 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). 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. Our proprietary StarBright XLT optical coatings dramatically increase transmission, up to 97.4% on our Schmidt corrector lenses. During check-out, you will be presented with several shipping choices and costs. Opticstar F6.3 Focal Reducer / Corrector. 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. Several functions may not work. Many focal reducers for refractors have a working distance (or back focus distance) of 55mm. Hi. Get ready for a night of astroimaging with your mount faster than previously thought possible with All-Star Polar Alignment. Bear in mind you can't squeeze blood out of a turnip, i.e. However, even though the imprint on the item states "Reducer / Corrector" please note that his is a reducer only. The reducer is we might presume designed to correct to some as yet un-measured extent, the image of a standard SCT. The problem with those SCT reducers is that they cause chromatic aberration and require refocusing when using parfocal RGB/other filters. This focal reducer is made to attach to the rear cell of Schmidt-Cassegrain or Maksutov-Cassegrain telescopes. Check out our 2022 telescope buying guide here! All rights reserved. In many cases, the answer is yes, especially for electronically-assisted astronomy (EAA). 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. An f/6.3 reducer is designed to reduce the focal ratio of an f/10 SCT to f/6.3. However, because the field curvatures in refractors and SCTs vary a lot, I would predict unpredictable effects inre: field curvature. In terms of reduction and correction - which are what reducer/correctors are supposed to do - both are superb. 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. Not one detectable iota of discernable difference. In some cases, focal reducers also act as field flatteners by correcting for field curvature and coma of the objective lens. All additional accessories mount onto the exterior/male threads. Meade and Celestron both sell such SCT-T adapters with the correct optical length. In the 1960s, Celestrons founder, Tom Johnson, created groundbreaking new telescopes never before seen on the consumer market. Your mileage may vary. Newtonian reflectors will seldom be able to accommodate the in-focus travel demanded by focal reducers. If used before or beyond the working distance, unwanted image distortion may result, especially when using cameras with larger sensors. 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 made in Japan 6.3 R/C and a made in China 6.3 R/C. Free shipping $189.95 If the reducer is placed elsewhere, at a position called the operating distance, the focal reduction factor will not be as advertised. 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. However, the China 6.3 R/C has noticeable internal reflections that I haven't figured out yet. 3. I was going to measure the difference in grams, but my lovely wife caught me trying to use her precious, high-tech kitchen scale for the cause, and put the kibosh on it. For me, I was looking for, and planning to keep, the one that yielded the greatest reduction. However, this also came at a cost, as the sky background in the Antares was slightly brighter. . Even though they may have been slightly dimmer, galaxies were a bit easier to tease out of the urban light soup I deal with. Celestron Focus Motor for SCT, EdgeHD & 8" RASA, Celestron C6 0.63 reducer/flattener back focus. Figure 6 shows a 1.25" focal reducer from GSO configured with a ZWO ASI224MC camera. Some coma is visible in the corners, but the image is quite good for EAA applications. 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. Reducer Lens .7x - EdgeHD 1100 Learn More. But is there a difference in quality between the Antares and the Celestron or Meade focal reducers? I happily cycle through LRGB filters to build the image rather than do a whole run of one filter at a time. 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. Place the plastic covers on the lens when not in use to reduce the dust collection. The Antares focal reducer comes in small box. Shipping will be via the cheapest shipping method which will vary depending on the items in your order. Never noticed any anomalies with this unit. 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. As a Barlow's magnification increases with increasing distance from the Barlow, a focal reducer's reduction increases with increasing distance from the reducer. If used with other f/ratios, the field flattening characteristic may be unpredictable. 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. 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 to receive sale alerts, news about upcoming celestial events, and telescope tips from our experts! With the barrel 1.25 reducer won't focus, all I get is fuzzy snowballs. Most Feather Touch focusers cost between $300-$350. Designed distancing using the reducer with a 1.25 visual back and 1.25 Televue mirror diagonal; Because of their distinct optical design, slower Schmidt-Cassegrain telescopes (SCT) with focal ratios of f/10 require a different design of focal reducer compared to refractors. 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. 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. Quite interestingly it bears the very same engravings of the Meade 4000 r/c (including "series 4000") except for "MEADE". This also resulted in the clear aperture of the Antares being about 39-39.5mm, versus the Celestrons 41mm. Unleash the full pointing accuracy of your Celestron computerized telescope with a specialized telescope control software suite. I am a purely visual observer, so will evaluate for visual use only. One of the most important factors in a telescope is its transmissionthe percentage of light that reaches the focal plane. Even though the manufacturer did not specify the working distance or focal length of this reducer, it is easy to see from this plot that this item provides its stated reduction of 0.5x when it is placed at a working distance of 51.5mm between the base of the threads on the mount and the focal plane of the eyepiece or camera. The lens has a knurled surface, providing a tremendous gripping surface for threading/unthreading. Manish holds a Master's degree in Electrical Engineering from Virginia Tech and an MBA from the Kellogg School of Management at Northwestern University. * Not a Retail Store * 16313 Arthur StreetCerritos, CA 90703, USA, Availability: Item has been discontinued by Agena and we no longer carry this item. More important, its clear that the Antares is a reducer/corrector, just like the Celestron and not merely a reducer. Brightness, color, and contrast were subtly different, but could be as much the day they were coated as any real difference in the two brands. Meade once made an f/3.3 focal reducer for SCT scopes. 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. For example, an 8" SCT without a focal reducer has an illuminated field of 38mm at 50% fall-off. Most refractor manufacturers such as William Optics, Tele Vue Optics, Explore Scientific, Sky-Watcher, William Optics, and Stellarvue make their own focal reducers optimized for use with their telescopes. 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"). Some faster refractors with a focal ratio of f/6, for example, only require field flatteners and not focal reducers. 2023 Celestron, LLC. JavaScript seems to be disabled in your browser. 3. Reducer Lens .7x - EdgeHD 800 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. Fumbling around in the dark, fine threads might be a problem. What is likely is that fatigue sets in, and also that as the targets move toward or a way from the meridian there will be changes for that reason alone. If you are using a camera that has a back focus of less than 55mm, additional spacer rings will be required between the reducer and the camera. Powered by Invision Community. Will not focus with the stuff I have. The equations in the Appendix show how this all works. That said any comparison reviews are helpful. And when used in some refractors, the field flattening is not as accurate as it is in the f/10 SCTs. Reducer Lens .7x - EdgeHD 1400 Learn More. Hmmm . The working distance or required back focus, explained above, is usually specified and is far more important in practice. But when not in the box or on the telescope, there is no cover for the other end. Sign up for our newsletter to get exclusive deals, observing tips, and new product announcements. SKU: CEL-94245. Things change but when I rebought I got an Antares and it seems about the same to me. Celestron or Antares f/6.3 focal reducer for SCT? You can probably eke out 1.2 without noticing serious vignetting, which is a field stop of 31.5mm. Observing the microscopic world has never been easier! ED stands for "extra-low dispersion," which refers to the composition and optical properties of the glass used for the lenses. I use the Celestron version and it seems OK for both visual and imaging. Perfect for the serious student, professional scientist and discriminating hobbyist. It works fine but you should stick with 1.25 EPs; or can use 2" EPs without corrector. 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. We have tested our current batch and it works with Meade, Celestron, and Baader SCT accessories. Does anyone know if the Antares 4000 focal reducer is as good as the Celestron focal reducer. 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). Wonder how they would stack up with a Japanese 6.3. 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. This "speeds up" the optical train by reducing the focal length and magnification of the scope, requiring less time to integrate the same signal. The Antares f6.3 focal reducer screws directly to the visual-back thread of all popular SCTs and converts f10 instruments to f6.3. Just point the telescope at any three bright objectsstars, bright planets, or even the Moonand your telescope can orient itself with the night sky. Please re-enable javascript to access full functionality. 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. As per the OP I still can't see any reason to buy the Celestron for significantly more $$$. a Tele Vue Panoptic), or a Plossl eyepiece with an apparent field of view of 50 and a focal length of 32mm. Whereas the Celestron threaded smoothly onto the scope, the Antares chattered and squeaked a bit more so when being removed. 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. Specially-designed focal reducers are available for use with these telescopes. These reducers can also be used for visual observing with SCT scopes with eyepieces with a field stop as large as 24-27mm. An eyepiece with a 27mm field stop yields a true field of 1.03 in the C6 at f/10. I've looked through one from Meade and first impression was that it was like the Celestron version. Add a 0.63x reducer, and the brightness of extended objects increases by (1/0.63)2 = 2.5. Orders placed after 12:00 PM Pacific Time will be shipped the next business day. The reducer fits all Meade and Celestron . As a consequence, the standard f/6.3 and f/3.3 focal reducers for SCT scopes do not work. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. It has only one cover, which surprised me. Reviews. I have both the Antares and the Celestron reducers. Thank you so much for the informative article, I now understand better how to integrate my reducer into my system to get better performance. 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. Can you help me? The threads were similar on the eyepiece end, but a bit smoother. For both imaging and visual observing, these reducers also improve image sharpness at the edge of the field by correcting for coma and field curvature. 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. Most manufacturers provide this specification. DUE TO EXTREMELY HIGH DEMAND, WE WILL NOT BE TAKING NEW ORDERS UNTIL MONDAY, DECEMBER 14. No experience with the Antares reducers, but I haven't personally seen a difference between Celestron and my current pair of made in Japan Meade reducers. Reducer Lens .7x - EdgeHD 800 Learn More. The Celestron f/6.3 is ~150 compared to the Antares at ~70. Figure 2 shows the effective of a focal reducer on the light from a telescope objective. I own both and concur heartily. 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. Reducer - Corrector Learn More. 1.2" in that scope is a field stop of 43mm at f/10 and 27mm at f/6.3. What an enjoyable read and detailed comparison. 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. Planetarium software package which provides easy-to-understand explanations and impressive visuals of all kinds. The Reducer/Corrector can also be used for terrestrial digiscoping. 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. 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. As another example,GSO makes focal reducers for their line of Ritchey-Chretien imaging telescopes. Thanks Peter! Sign up for our newsletter to get exclusive deals, observing tips, and new product announcements. No difference. 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. Field stop diameters are one of the specified specs of eyepieces. 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 have this one Opticstar F6.3 Focal Reducer / Corrector. But the diameter of the image circle decreases by a factor of 0.63 to about 24mm. However, these will not impact optical performance. The stars at the edge could be worse or better. The previous post shows the reducer on what appear to be two different refractors. . Unlike . And, the reality is that every F/6.3 RC out there Celestron, Hirsch, Astromania, etc., etc. I don't know. I've never found my 0.63 reducer causing CA when used with my SCT. Housings, threads, reduction, correction, blah, blah, blah. USD $80.00. External Focusers for Schmidt-Cassegrain Telescopes 3.1 The Basics of SCT Threads Images in the Celestron tended to appear ever-so-slightly dimmer (maybe? 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). control and Sky Viewer display makes selecting your target easy. It's an either/or proposition: reducer and 1.25", or 2", but not 2" and reducer. I only have the Celestron f/6.3. 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! No results, please adjust your filters. Each focal reducer has a fixed specification called the working distance or required back focus. Reducer Lens .7x - EdgeHD 925 Again, these focal reducers are often provided by the telescope manufacturer. 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). 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. Please Log in to save it permanently. This would tell us exactly how well aberrations are corrected. If I had to guess, the difference is maybe 10-15 grams. The resultant reduction factor was measured to be 0.46x. It was also a little brighter in the center of the field with subtle darkening in the outer 20% or so. OPT Product Number: AE-SCTFR specifications Warranty 2 Year Warranty Works as advertised! 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. Antares or Celestron? 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. F6.3 Focal reducer for F/10 or higher telescopes, 43mm aperture, 4-Element, Fully Multicoated. Assuming you use the reducer with the stock 1.25" diagonal, it will operate at f/6.3. This filter threads on to the rear cell of your Celestron or Meade SCT telescope. 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). Depending on the design of the telescope, they may require separate focal reducers if they require focal reducers at all. 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. I have/had both the Celestron (Japan) and Antares units. Request stock alerts and we'll let you know when the item is back in stock. The most commonly available focal reducers for SCTs are the f/6.3 reducers from Celestron and a similar f/6.3 focal reducer from Meade. A focal reducer does just the opposite of a Barlow lens or focal extender. 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. Reproduction without permission prohibited. 800-483-6287 I have an 8SE, and am thinking about getting a focal reducer. Rather than a direct side-by-side, I swapped the reducers so that I was using them on the exact same, well-collimated instrument.

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