Go behind the scenes with Celestrons product development team and learn more about our award-winning and patented innovations. Antares f/6.3 Focal Reducer for SCTs - Awesome Astro 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. Celestron or Antares f/6.3 focal reducer for SCT? 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. I use it on my C8 SCT with a 1000d, and it seems to do everything written on the tin. It covers the basic optics and design specifications of a focal reducer, and goes through some practical factors to consider when selecting and using a focal reducer. No rainchecks will be issued for items out of stock at OPTcorp.com to match a competitor's price. Thanks for pointing this out. Thanks guys, appreciate the feedback. Fumbling around in the dark, fine threads might be a problem. Product Details. No small animals were harmed in making these observations. 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. Benefits limited to hardware and conditions? This should not be the case if they have their purportedly different focal lengths. If you want to use them for visual - try maybe long focal length eyepieces rather than the reducer. Increase that distance, and greater reduction results and visa versa. Refractors, or SCTs with external focusers, may not have sufficient in-travel to reach focus in some configurations. 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. 2023 Celestron, LLC. We reserve the right to verify a competitor's advertised price and the availability of the item. Reducer - Corrector Learn More. Figure 6 shows a 1.25" focal reducer from GSO configured with a ZWO ASI224MC camera. 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. Is that distance D= Fo-d1=Fo-(d2/MR)? riklaunim Members 559 3,445 Location: Poland Posted October 11, 2010 They are reported as identical. With both, using the same diagonal set-up, the exact same stars were visible at the very edge of the FOV. Thanks for the extremely valuable article. Reducer Lens .7x - EdgeHD 800 These reducers can also be used for visual observing with SCT scopes with eyepieces with a field stop as large as 24-27mm. I happily cycle through LRGB filters to build the image rather than do a whole run of one filter at a time. Given the results of Test #1, I wanted to see if there was any truth to this assumption. Ive owned Celestron, Meade, and Antares models over the years at least a couple of each. All rights reserved. Focal reducers also move the effective focal plane of the objective inward, that is, towards the objective (see Figure 1). Style: 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. You attach the focal reducer to the rear port on a SCT and can keep it covered. Reducer Lens .7x - EdgeHD 925 Learn More. With the Celestron Reducer/Corrector Lens, thats precisely what you get. 3. 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. . . JavaScript seems to be disabled in your browser. 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. If used before or beyond the working distance, unwanted image distortion may result. I'm going with the Celestron. 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 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. 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. Completely stuck, completely frustrated. 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. Newtonian reflectors will seldom be able to accommodate the in-focus travel demanded by focal reducers. Keep in mind that these differences were very subtle, and could be due to normal variations in coatings among different runs, and not necessarily unique to the brands. Add a 0.63x reducer, and the brightness of extended objects increases by (1/0.63)2 = 2.5. 160K views 9 years ago This video is a complete overview of focal reducers and how they function applying to telescopes. Antares F/6.3 SCT Focal Reducer | OPT Telescopes But is there a difference in quality between the Antares and the Celestron or Meade focal reducers? Please re-enable javascript to access full functionality. Most manufacturers provide this specification. More about this below. First, let's have a look at some key optical parameters are needed to understand focal reducers. If it's positioned further from the eyepiece or camera and closer to the telescope objective, the reduction factor increases. I only have the Celestron f/6.3. None of this was offensive, nor did it interfere with views in any significant way. Many focal reducers for refractors have a working distance (or back focus distance) of 55mm. Possibly the design of the Antares was changed .. JavaScript seems to be disabled in your browser. The C8 has no noticeable vignetting with a 32mm Plssl in the f/6.3 reducer. which looks like the same one. Celestrons patented StarSense Technology makes it easier than ever to locate objects in the night sky, even if youve never used a telescope before. 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. I don't know. 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. 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). 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. Your mileage may vary. 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. For the best experience on our site, be sure to turn on Javascript in your browser. But I am rusty, can you condense a bit for me please? No negative issues to report. Because I have not heard any complaints about the made in China R/C. Focal reducers for many SCTs and their flat-field equivalents usually have a back-focus distance of 105mm. 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. Astro-Tech Schmidt-Cassegrain f/6.3 Focal Reducer Field Flattener Celestron or Antares? There will be no shipments on 3/1/2023, 3/2/2023, or 3/3/2023 (March 1st - March 3rd, 2023). Manish Panjwani has been an active amateur astronomer since before Halley's Comet last flew by our neighborhood. They are also less expensive than many external focusers of similar build quality. Focal Reducer, 2", 0.7X. With this telescope and this focal reducer, it does not help to move to a 2" eyepiece and a 2" diagonal as the visual view will be akin to looking through a porthole within the larger apparent field of view of the eyepiece. 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. There is one difference though the Antares came with only one lens cap whereas the Celestron had a cap for both ends. No retailers currently carry this product. 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. The more focal reduction, the further inward the focal plane will be. Optically, it consists of a four-element lens that is fully multi-coated for high contrast and resolution. 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. 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. Whereas the Celestron threaded smoothly onto the scope, the Antares chattered and squeaked a bit more so when being removed. Again, to my surprise, there was absolutely no difference between the Celestron and Antares on any star. 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. This filter threads on to the rear cell of your Celestron or Meade SCT telescope. 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. We will be glad to help. 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. Some faster refractors with a focal ratio of f/6, for example, only require field flatteners and not focal reducers. Is there likely to be any differences in performance between using these on an 8 or something smaller like my 6SE? 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. Copyright 2003-2022 Agena AstroProducts. Explore Scientific Keys to the Universe Sale. 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. Very helpful, thanks a lot for this article! - thanks. As a consequence, the standard f/6.3 and f/3.3 focal reducers for SCT scopes do not work. The reducer is we might presume designed to correct to some as yet un-measured extent, the image of a standard SCT. They usually have a 2" barrel that slides into the telescope focuser. However, doesn't fit in the telescope and even if it did wouldn't work. . Practical Considerations of Focal Reducers, 4.2 Back Focus Requirements of Focal Reducers, GSO makes focal reducers for their line of Ritchey-Chretien, Celestron makes a series of focal reducers for the Edge HD line, 0.75x focal reducers for these telescopes, focal reducer for an 8-inch Celestron EdgeHD, A Primer on T-Rings and T-Adapters for Astronomy and Astrophotography, Choosing the Best Telescope for Beginners 2023, Top Night Sky & Astronomy Events in August 2022, Top Night Sky & Astronomy Events in July 2022, Selecting a Baader Planetarium Star Diagonal, A Guide to Choosing Astronomy Eyepieces for Binoviewers, Choosing a Magnifying Finder Scope for Your Telescope, A focal reducer will provide its design reduction factor only when it is placed at the exact working distance from the focal plane of the eyepiece or camera, Reducing the operating distance, that is, moving a focal reducer closer to the eyepiece or camera increases its reduction factor, or conversely reduces the amount of focal reduction. For the best experience on our site, be sure to turn on Javascript in your browser. 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. The female end attaches to the rear cell of the telescope. 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. 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. It might work but it does not tell us anything about how well or to what extent the product works to correct the field of an SCT. 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. I would not use the reducer with a 2" diagonal or eyepiece in the C6. Sign up to get exclusive deals, observing tips, and new product announcements. I have Hirsch focal reducer, which is yet another clone of the Celestron reducer. Start here to find the perfect telescope for you! 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). 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. The Reducer/Corrector can also be used for terrestrial digiscoping. However, the export of some items may be restricted outside the US due to size or manufacturer restrictions. Easy solution found a very tiny dab of super lube on the threads and all was well and quiet.. Read our 101 article or get in touch. The resultant reduction factor was measured to be 0.46x. 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. The equations and argument in the Appendix of this article shows the relationship between the working distance and the reduction factor. In some cases, focal reducers also act as field flatteners by correcting for field curvature and coma of the objective lens. One focal reducer will not achieve optimum results with all types of telescopes, so there is no universal' focal reducer. I've heard and read all kinds of things about the Antares being only a reducer and not a corrector, etc. 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. 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. Nowadays I tend to use the Celestron more with my refractors for imaging and viewing. It is not a corrector or flattener. Copyright 2003-2022 Agena AstroProducts. But in the end they both do pretty much the same thing and it sounds like any performance difference is subtle. Back-Focus 101: DSLR Cameras & the Celestron f/6.3 Reducer - YouTube All Rights Reserved. Sign up for our newsletter to get exclusive deals, observing tips, and new product announcements. Enter it during checkout! I've seen some older threads saying that the Celestron, Meade and Antares FRs are all the same and manufactured in the same factory. My Celestron was made in China and the Antares in Canada. If used before or beyond the working distance, unwanted image distortion may result, especially when using cameras with larger sensors. 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. Also read the reviews here, including those at 4 stars. How to Set the Correct Back Focus for Your Telescope (Guide) I wish there was. 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. because they really dont matter. InternetSales@optcorp.com. As one increases, the other decreases. We do not price match competitors if they are out of stock. It is recommended for . 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. Hello! CPWI has an extensive object database, employs PointXP mount modeling, and more. As a result, the smaller tube may cut into the light cone and effectively reduce the working aperture of the telescope. This focal reducer is made to attach to the rear cell of Schmidt-Cassegrain or Maksutov-Cassegrain telescopes. If you do so, you will achieve the design reduction factor. From the SkyProdigy, a telescope so smart it can align itself, to our high-performance EdgeHD optical system, weve revolutionized the hobby of astronomy for beginners and advanced amateurs alike. Unique focal reducer and field corrector lens accessory Reduces the focal length and f/ ratio of your Schmidt-Cassegrain telescope by 37% Provides a dual focal ratio instrument, without sacrificing image quality Compatible with all Schmidt-Cassegrain telescopes (see compatible list in description) Share Customers Also Purchased Description 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. Does anyone know if the Antares 4000 focal reducer is as good as the Celestron focal reducer. 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. Nebula Filters. Not noticed any optical problems. Dedicated focal reducers for refractors are intended primarily for imaging, not visual observation. The problem with those SCT reducers is that they cause chromatic aberration and require refocusing when using parfocal RGB/other filters. Since the Celestron and Antares are supposed to have different focal lengths and spacing specs, I expected different results. If I had to guess, the difference is maybe 10-15 grams. Besides observing from his heavily light polluted backyard in Los Angeles, Manish enjoys conducting astronomy outreach programs in local schools. Such an image circle is still large enough to encompass the relatively large sensor of many deep-sky astronomy cameras. We process your personal data as stated in our. Does anyone have any experience with the Celestron and Antares focal reducers? Since 2008, Brian has taught astronomy to tens of thousands of stargazers through his websites OneMinuteAstronomer.com and CosmicPursuits.com. You currently have javascript disabled. Does anyone know if the Antares 4000 focal reducer is as good as the Celestron focal reducer. 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. Some third-party vendors also make reducers for SCT scopes. Never noticed any anomalies with this unit. Sign up for OPT news, exclusive offers, and updates on the latest gear!