Also, the focusers of most Newtonians do not have enough in-travel to accommodate a focal reducer. A useful thing to know is how far from the objective lens (for a refractor) is the focal reducer located. Once focused it's pretty good. 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. Since the Celestron and Antares are supposed to have different focal lengths and spacing specs, I expected different results. 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. Agena's Guide to Focal Reducers - Agena Astro As a result, the smaller tube may cut into the light cone and effectively reduce the working aperture of the telescope. Rather than a direct side-by-side, I swapped the reducers so that I was using them on the exact same, well-collimated instrument. But in the Japan version I have never noticed any anomaly like the ghosting in the China R/C. 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. Assuming you use the reducer with the stock 1.25" diagonal, it will operate at f/6.3. . Sign up for our newsletter to get exclusive deals, observing tips, and new product announcements. I don't know. Sharpness is essentially the same. 2023 Celestron, LLC. This appendix summarizes how this works based on simple equations from the book Telescope Optics by Rutten and van Venrooij. 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? Orders placed after 12:00 PM Pacific Time will be shipped the next business day. This rugged, 3-in-1 device features a true tactical 3-mode flashlight, a hand warmer, and a portable power bank for recharging your personal electronics on the go. Celestron or Antares? 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. Again, swapping back and forth for a couple of hours on M44, M35, and several brighter stars, I examined the shape of specific stars near the edge of the field with both correctors. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. 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. Wow, that is a very detailed discussion! I have an 8SE, and am thinking about getting a focal reducer. So it provides a 0.63x design reduction factor when used with an f/10 SCT at the specified working distance. InternetSales@optcorp.com. 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. 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. An image of about 24mm across, approximately, allows an observer to use a 1.25" eyepiece with a maximal field stop. 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. 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. If the reducer is placed elsewhere, at a position called the operating distance, the focal reduction factor will not be as advertised. Looking forward to the day when I can do a shoot-out between a Japan and China Celestron, just for kicks. In terms of reduction and correction which are what reducer/correctors are supposed to do both are superb. Each focal reducer has a fixed specification called the working distance or required back focus. Ive owned Celestron, Meade, and Antares models over the years at least a couple of each. But nearly every observer who installs one of these devices is pleased with their performance. 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 internal surfaces are blackened and glare-threaded to provide the highest contrast. Never noticed any anomalies with this unit. This is a. Our patented SkyAlign alignment technology makes setting up a computerized telescope simple, fast, and accurate. 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. Reducer - Corrector | Celestron 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. Not a bit. 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. F 6.3 focal reducer/corrector. - Discussions - Stargazers Lounge For visual use, this means you get lower power with the same eyepiece and a wider field of view. For the best experience on our site, be sure to turn on Javascript in your browser. Style: The telescope side of the barrel is often threaded with an M48 x 0.75 thread for standard 2" astronomy filters. Best evidence would by obtained by using a camera and evaluating the image both by eye and with a computer analysis. Images made with my ZWO 533 camera testing both show them to be essentially the same. A slight nod to the Antares for heft and higher transmission, but points to the Celestron for nice threads and better contrast. Your price: $579.00. Free shipping $189.95 In both cases will end with a similar tfov. As one increases, the other decreases. Sign up to receive sale alerts, news about upcoming celestial events, and telescope tips from our experts! But the smaller image circle means there is a limit to the field stop of an eyepiece that can achieve an unvignetted image. WiFi technology encircles the globe in a web of connectivity, knowledge, and information. Does anyone know if the Antares 4000 focal reducer is as good as the Celestron focal reducer. 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. Focal reducers for these relatively fast ED refractors are generally for imaging only, not for visual observation. 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. There is one difference though the Antares came with only one lens cap whereas the Celestron had a cap for both ends. 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. Upgrading the Focuser of Your Schmidt-Cassegrain Telescope - Agena Astro I would not use the reducer with a 2" diagonal or eyepiece in the C6. Reducer Lens .7x - EdgeHD 1100 Learn More. Your eyepieces are the first accessories you should learn to use with your telescope. A reducer is a set of converging (or positive) lenses that cause the light from a telescope objective to converge at a steeper angle to the focal plane as if it were coming from an objective with a faster (lower) focal ratio and a shorter focal length. The lens is housed in machined aluminum for are machined aluminum black anodized. The Celestron is both a corrector and focal reducer and the Antares is just a focal reducer. This is very impressive performance given how hard this problem is to mitigate in general. The focal length and design working distance for this focal reducer were not available from the manufacturer. However, some focal reducers can be used over a wider range of working distances, especially those with simpler optical design, and especially when used with cameras with smaller sensors. 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. 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. The lens has a knurled surface, providing a tremendous gripping surface for threading/unthreading. 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. Celestrons aplanatic EdgeHD optics revolutionized astroimaging. Request stock alerts and we'll let you know when the item is back in stock. 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). I was referring to the C6 to answer you specifically. He also holds a Ph.D. in engineering physics from McMaster University. The reducer fits all Meade and Celestron . Can you tell me about the use of reducers in Maksutov-Cassegrain telescopes? The Antares f6.3 focal reducer screws directly to the visual-back thread of all popular SCTs and converts f10 instruments to f6.3. 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 f/6.3 SCT Focal Reducer - Rother Valley Optics Ltd This is the simplest way to attach your ASI121 to your telescope. Some are available in 1.25" barrel format but with C threads. Thanks guys, I'm trying to get my ZWO ASI120MC-S to work with my 90mm Meade. Since the focal length of the reducer, FR, is fixed, as d2 increases then MR decreases. Completely stuck, completely frustrated. Focal Reducer for SCT - ACF - Stargazers Lounge Reducer Lens .7x - EdgeHD 1400 Reducer - Corrector To test this, I used three set-ups: 1. Michael 1 ronin Members 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. Antares Click Lock Visual Back - Cats & Casses - Cloudy Nights They both are great and I doubt my eyes could detect a difference in any one of them including the Japan version. In some cases, focal reducers also act as field flatteners by correcting for field curvature and coma of the objective lens. Manish Panjwani has been an active amateur astronomer since before Halley's Comet last flew by our neighborhood.