* Not a Retail Store * 16313 Arthur StreetCerritos, CA 90703, USA, Availability: Item has been discontinued by Agena and we no longer carry this item. We will be glad to help. Increase that distance, and greater reduction results and visa versa. I use it on my C8 SCT with a 1000d, and it seems to do everything written on the tin. 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. 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. looks virtually identical, except for the lettering. Focal reducers for these relatively fast ED refractors are generally for imaging only, not for visual observation. Thanks. 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. 2. Can you help me? Wow, that is a very detailed discussion! Because most modern Newtonians already have relatively fast focal ratios, these telescopes do not usually use focal reducers. 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. 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. In this case, d2 = FR/2, which means the back of the focal reducer is located at a distance FR/2 from the camera or eyepiece. How does it look thats what matters. I am a purely visual observer, so will evaluate for visual use only. Most amateur astronomers are familiar with a Barlow lens (or a focal extender), a negative or diverging lens that effectively increases the focal length and the focal ratio of a telescope's objective lens. However, because the field curvatures in refractors and SCTs vary a lot, I would predict unpredictable effects inre: field curvature. Get ready for a night of astroimaging with your mount faster than previously thought possible with All-Star Polar Alignment. 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. Product Details. Using this same example of an 8" SCT and a 0.63x reducer, a visual observer can also enjoy brighter images and a wider field of view. Stars had a tiny bit more sparkle and pop. There will be no shipments on 3/1/2023, 3/2/2023, or 3/3/2023 (March 1st - March 3rd, 2023). Sharpness is essentially the same. For visual use, this means you get lower power with the same eyepiece and a wider field of view. CPWI has an extensive object database, employs PointXP mount modeling, and more. Not a bit. By using this site, you agree to our Terms of Use. The problem with those SCT reducers is that they cause chromatic aberration and require refocusing when using parfocal RGB/other filters. I've seen some older threads saying that the Celestron, Meade and Antares FRs are all the same and manufactured in the same factory. 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. But in the Japan version I have never noticed any anomaly like the ghosting in the China R/C. Thanks guys, I'm trying to get my ZWO ASI120MC-S to work with my 90mm Meade. I have this one Opticstar F6.3 Focal Reducer / Corrector. I think that the FRs made in Japan in the day may have been better. 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 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. 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. For me the Antares was a little brighter and had the least scatter by a bit so the better coatings won. No rainchecks will be issued for items out of stock at OPTcorp.com to match a competitor's price. They only publish the value of D, the working distance (sometimes called the back focus distance) and the design reduction factor MRD. The threads were similar on the eyepiece end, but a bit smoother. The telescope side of the barrel is often threaded with an M48 x 0.75 thread for standard 2" astronomy filters. I even lost track of which reducer I was using. The Antares f/6.3 Focal Reducer for Schmidt-Cassegrain Telescopes is a low-price option for reducing the focal length of your Schmidt-Cassegrain telescope from f/10 to f/6.3. With spring galaxy season here, I decided to pick up a couple more to compare in a head-to-head shoot out. Since then, Agena has become one of the leading online retailers of telescopes and astronomical accessories worldwide. Observing the microscopic world has never been easier! 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. 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. 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. 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"). These reducers can also be used for visual observing with SCT scopes with eyepieces with a field stop as large as 24-27mm. When the camera sensor is placed at this distance, the reduction factor of these reducers is 0.75x. 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. As mentioned in Section 2 of this guide, the reduction factor of a focal reducer depends on its position in the optical path relative to the eyepiece or camera. No negative issues to report. 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. 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. It seems right to put some distance between the camera and the focal reducer, right? I'd favor the Japanese Celestron version over the others that are commercially available. Just point the telescope at any three bright objectsstars, bright planets, or even the Moonand your telescope can orient itself with the night sky. SKU: CEL-94245. Sign up for OPT news, exclusive offers, and updates on the latest gear! ED stands for "extra-low dispersion," which refers to the composition and optical properties of the glass used for the lenses. No retailers currently carry this product. Celestron is considered better in terms of QA, less likely to come with free dust, hair or fingerprint. I read another thread in a different forum about F6.3 reducer correctors and one amateur posted an image about glue coming out of an astromania f6.3 reducer which he planned to return. Even though they may have been slightly dimmer, galaxies were a bit easier to tease out of the urban light soup I deal with. As a consequence, the standard f/6.3 and f/3.3 focal reducers for SCT scopes do not work. 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. 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). ), ASI Air Plus - Connected items are 'greyed out', Cost of ordering used equipment U.S. - Can can more than double figure, Tuthill Isostatic Mount and Star Trap Power Module. I have had the Japan unit on the back of my C5 since 1994 or thereabouts. I found both to be very good. 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. 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. Benefits limited to hardware and conditions? 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. For example, an 8" SCT without a focal reducer has an illuminated field of 38mm at 50% fall-off. The female end attaches to the rear cell of the telescope. The reducer is we might presume designed to correct to some as yet un-measured extent, the image of a standard SCT. The Reduction Factor and the Amount of Reduction are inversely related. 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? 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. 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. For this shoot-out, I used a standard Celestron C8 with Starbright coatings. 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. I've never found my 0.63 reducer causing CA when used with my SCT. I wonder whether, for example, Antares focal reducer for SCT belongs to the latter category. Can these economical focal reducers from GSO and other vendors result in good images? 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. For the best experience on our site, be sure to turn on Javascript in your browser. 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. Reducer Lens .7x - EdgeHD 925 Learn More. This innovative software solves the time-consuming problem of trying to pinpoint the North Celestial Pole. 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. We have placed cookies on your device to help make this website better. If I had to chose one, I would base my decision on your level of light pollution perhaps the Antares for its slightly higher transmission if you live under less light polluted skies, but the Celestron for its greater contrast if you are dealing with a suburban or urban light dome. 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. That includes, for example, a 1.25" eyepiece with an apparent field of view of 68 and a focal length of 24mm (eg. That is definitely a 2" eyepiece, but it is not a large or long focal length 2" eyepiece. This is a. Photographically you also get a wider field and much shorter exposures. Well done. 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. A useful thing to know is how far from the objective lens (for a refractor) is the focal reducer located. 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. But the diameter of the image circle decreases by a factor of 0.63 to about 24mm. 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. It has only one cover, which surprised me. Upon close inspection, it was clear that the housing of Antares assembled in Canada version was a little more substantial than the Celestron. If you do so, you will achieve the design reduction factor. . 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. 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. 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. Melotte 15 - First Process in PixInsight (easy! 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). 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. That said any comparison reviews are helpful. We will match any online price that we confirm as valid. 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 the best experience on our site, be sure to turn on Javascript in your browser. The nominal design reduction factor of these reducers is typically 0.5x. Meade once made an f/3.3 focal reducer for SCT scopes. If it's positioned further from the eyepiece or camera and closer to the telescope objective, the reduction factor increases. These reducers have a back focus (or design working distance) of 80mm. They usually have a 2" barrel that slides into the telescope focuser. Both exhibited consistent reduction, identical field flattening, and edge correction properties, and both were high quality optically and mechanically. Watch this before you buy Celestron 8SE SCT, or a Focal Reducer or a Hyperstar 7,758 views Mar 28, 2018 145 Dislike Share Ray's Astrophotography 42.3K subscribers Note: I am not paid or. The more focal reduction, the further inward the focal plane will be. 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 Celestron f/6.3 is ~150 compared to the Antares at ~70. The same illumination you have at the edge of a 27mm field, the C8 has at the edge of a 38mm field. As a Barlow's magnification increases with increasing distance from the Barlow, a focal reducer's reduction increases with increasing distance from the reducer. The female end attaches to the rear cell of the telescope. JavaScript seems to be disabled in your browser. Nebula Filters. Better images are also obtained when using these focal reducers at a reduction factor of 0.5x 0.8x, approximately. These reducers can also be used for visual observing with SCT scopes with eyepieces with a field stop as large as 24-27mm. Most Feather Touch focusers cost between $300-$350. The working distance of the GSO 0.5x focal reducer with 1.25" barrel and the GSO 0.5x focal reducer with 2" barrel is about 51mm to 53mm, approximately, from the middle of the metal cell that holds the lens. Stars in the corner of the image frame are indistinguishable between the Antares and the Celestron. . All additional accessories mount onto the exterior/male threads. The review is a subjective visual impression, which is interesting but not best evidence. 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. 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. Your price: $579.00. Thanks guys, appreciate the feedback. One problem with getting opinions is that most of use do not have both reducers or have never done a side by side comparison. Have always disliked the crude, noisy SCT threads, but I get it. Specially-designed focal reducers are available for use with these telescopes. So ab6110 is asking for a FR only without coma correction, there are a couple of brands who make special reducers for the ACF. Details: The item must be the identical item, brand name, size, weight, color, quantity and model number. Now It only focuses near things, like some kind of macro zoom. Community Forum Software by IP.BoardLicensed to: Cloudy Nights, E of San Francisco Bay and W of the Awahnee, This is not recommended for shared computers, reviews here that suggest a coating problem, Back to Celestron Computerized Telescopes, Looking for advice on first refractor and camera. 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 . 3. Go behind the scenes with Celestrons product development team and learn more about our award-winning and patented innovations. A focal reducer does just the opposite of a Barlow lens or focal extender. It must be in stock at the time of Price Match for us to make a guarantee. No results, please adjust your filters. and you will be fine. Learn more about extra solar planets imagery, 3D Star rendering, observation planning, telescope control, multiple-panel printing, and much more. Not noticed any optical problems. Sign up to get exclusive deals, observing tips, and new product announcements. In some cases, focal reducers also act as field flatteners by correcting for field curvature and coma of the objective lens. There may have been an almost imperceptible difference, but the Antares and Celestron were producing precisely the same reduction. This should not be the case if they have their purportedly different focal lengths. Opticstar F6.3 Focal Reducer / Corrector. Have a promo code? Obviously bright objects like Jupiter or The Moon show the reflections. 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). Still not sure what is the right gear for you? But while the image gets brighter, the size of the image circle gets proportionately smaller. An eyepiece with a 27mm field stop yields a true field of 1.03 in the C6 at f/10. Read our guide! At least these two units I tested make the answer - whatever. Each focal reducer has a fixed specification called the working distance or required back focus. In many cases, the answer is yes, especially for electronically-assisted astronomy (EAA). 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. None of this was offensive, nor did it interfere with views in any significant way. This focal reducer and field flattener consists of a four-element multicoated 40mm lens in a metal cell. This "speeds up" the optical train by reducing the focal length and magnification of the scope, requiring less time to integrate the same signal. I wont bother with differences in packaging, caps, etc. What an enjoyable read and detailed comparison. Hmmm . Such an image circle is still large enough to encompass the relatively large sensor of many deep-sky astronomy cameras. Thanks for pointing this out. This fully multi-coated lens provides maximum light transmission with near full-field illumination. This focal reducer is made to attach to the rear cell of Schmidt-Cassegrain or Maksutov-Cassegrain telescopes. They are designed (assuming you are referring to the f/6.3 version) for the f/10 light cone. . I also used several eyepieces including the ES 24mm/68, 17.5mm and 12.5mm Morpheuses, and a 10.5mm Pentax XL. To further factor out my natural astigmatism (I normally wear glasses while observing), I did the tests with my regular progressive lenses, single vision glasses I use when observing, and naked eye. Request stock alerts and we'll let you know when the item is back in stock. The reducer fits all Meade and Celestron . I have a made in Japan 6.3 R/C and a made in China 6.3 R/C. Many Ritchey-Chretien telescopes available today are made by GSO. 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. Reducer Lens .7x - EdgeHD 1100 Learn More. Is that distance D= Fo-d1=Fo-(d2/MR)? Field stop diameters are one of the specified specs of eyepieces. Reducer Lens .7x - EdgeHD 1100. If you place your camera at a different working distance, you will get a different reduction factor and perhaps unwanted distortion in the image. Celestrons award-winning Nature DX binocular gets a major upgrade with the addition of ED objective lenses. Also, the focusers of most Newtonians do not have enough in-travel to accommodate a focal reducer. Perhaps not exactly- there will be some uncertainty because of manufacturing tolerances and so forth, but it will be close. As a result, the smaller tube may cut into the light cone and effectively reduce the working aperture of the telescope. The lens that the ZWO comes with give a perfect wide angle image of what is in front of it. If a stronger level of focal reduction is used, say 0.5x, then the image circle may be too small to fill the sensor of larger cameras. It's highly unlikely that they could be so precisely identical unless they were. I doubt there is any difference between the Antares and the Celestron except price. My Celestron was made in China and the Antares in Canada. OPT Product Number: AE-SCTFR specifications Warranty 2 Year Warranty Works as advertised! Again, these focal reducers are often provided by the telescope manufacturer. Your eyepieces are the first accessories you should learn to use with your telescope. There is one difference though the Antares came with only one lens cap whereas the Celestron had a cap for both ends. 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. 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. 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. 160K views 9 years ago This video is a complete overview of focal reducers and how they function applying to telescopes. Edited by bluewater, 05 September 2020 - 11:27 AM. 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. It's easy! WiFi technology encircles the globe in a web of connectivity, knowledge, and information. which looks like the same one. 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. The resultant reduction factor was measured to be 0.46x. There are also third-party vendors such as Hotech. Besides observing from his heavily light polluted backyard in Los Angeles, Manish enjoys conducting astronomy outreach programs in local schools. 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. 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. 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. In such cases, we will be happy to take the item back as per our standard return terms. I had a Celestron, Antares and Hirsch for awhile and compared them over about a year.