Reproduction without permission prohibited. 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. Agena's Guide to Focal Reducers - Agena Astro 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). 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). Unleash the full pointing accuracy of your Celestron computerized telescope with a specialized telescope control software suite. 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. 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. He tested this on an 8 Celestron , I have a Celestron 6SE. For me, I was looking for, and planning to keep, the one that yielded the greatest reduction. The Antares f6.3 focal reducer screws directly to the visual-back thread of all popular SCTs and converts f10 instruments to f6.3. Some faster refractors with a focal ratio of f/6, for example, only require field flatteners and not focal reducers. But nearly every observer who installs one of these devices is pleased with their performance. It's an either/or proposition: reducer and 1.25", or 2", but not 2" and reducer. I have a Raspberry HQ camera, a Sony TV Zoom 12.5-75mm f1.8 and a Astromania 1,25" 0.5x focal reducer. We will match any online price that we confirm as valid. The easiest way to use a focal reducer is to make sure you place it at the specified working distance in front of your camera or eyepiece. Regardless, the difference was miniscule and is more than adequate on both and exceeds a 8 or 6 SCTs baffle tube diameter. 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. Celestron or Antares? All rights reserved. They usually have a 2" barrel that slides into the telescope focuser. It features a standard male SCT thread (2" OD, 24 TPI) on one side and a standard SCT female thread on the other. 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. 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 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. It's usually specified in millimeters. 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. In terms of reduction and correction - which are what reducer/correctors are supposed to do - both are superb. 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. The lens is housed in machined aluminum for are machined aluminum black anodized. if the illuminated field is 27mm wide without the reducer, it will be 27 x 0.63 = 17mm with it in place. 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. 2.2 Using a Focal Reducer at the Working Distance, 2.3 Adjusting the Reduction Factor of a Focal Reducer, 3.3 Focal Reducers for Compound Telescopes, 3.5 Focal Reducers for Ritchey-Chretien and Field Flattened Scopes, 3.6 Focal Reducers in 1.25" and 2" Barrel Formats, 4. . Such an image circle is still large enough to encompass the relatively large sensor of many deep-sky astronomy cameras. Optically, it consists of a four-element lens that is fully multi-coated for high contrast and resolution. As a Barlow's magnification increases with increasing distance from the Barlow, a focal reducer's reduction increases with increasing distance from the reducer. Because most modern Newtonians already have relatively fast focal ratios, these telescopes do not usually use focal reducers. 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! The resultant reduction factor was measured to be 0.46x. Completely stuck, completely frustrated. Nebula Filters. This means that there must be sufficient travel on the telescope focuser to make up for this. Thanks. Since the focal length of the reducer, FR, is fixed, as d2 increases then MR decreases. 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. 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. 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. 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. 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. Nada. 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. 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. An eyepiece with a 27mm field stop yields a true field of 1.03 in the C6 at f/10. More details are found in the Appendix of this article. Easy solution found a very tiny dab of super lube on the threads and all was well and quiet.. 2023 OPT Telescopes. I wont bother with differences in packaging, caps, etc. 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. 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. 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. These reducers can also be used for visual observing with SCT scopes with eyepieces with a field stop as large as 24-27mm. One problem with getting opinions is that most of use do not have both reducers or have never done a side by side comparison. Does anyone know if the Antares 4000 focal reducer is as good as the Celestron focal reducer. My Celestron was made in China and the Antares in Canada. JavaScript seems to be disabled in your browser. Optically, it consists of a four-element lens that is fully multi-coated for high contrast and resolution. 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. 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. Here, there was a subtle difference . I use it on my C8 SCT with a 1000d, and it seems to do everything written on the tin. But while the image gets brighter, the size of the image circle gets proportionately smaller. All additional accessories mount onto the exterior/male threads. It seems right to put some distance between the camera and the focal reducer, right? I own both and concur heartily. The more focal reduction, the further inward the focal plane will be. Reducer Lens .7x - EdgeHD 800 Learn More. All Rights Reserved. Depending on the design of the telescope, they may require separate focal reducers if they require focal reducers at all. 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. How about for visual observers? Housings, threads, reduction, correction, blah, blah, blah. At least these two units I tested make the answer - whatever. 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). It's easy! Copyright 2003-2022 Agena AstroProducts. In this configuration, the 29.5mm camera nosepiece and a 6mm extension ring positions the reducer at a working distance of 53.5mm from the camera sensor, which is located 12.5mm inside the front edge of the camera. 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. I wonder whether, for example, Antares focal reducer for SCT belongs to the latter category. F6.3 Focal reducer for F/10 or higher telescopes, 43mm aperture, 4-Element, Fully Multicoated. (Note: Using the simple equations above, the focal length of this reducer can be estimated to be about 350mm). 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 https://www.celestron.com/products/reducer-corrector, //cdn.shopify.com/s/files/1/1935/4371/products/94175_reducer_corrector_01.jpg?v=1603736883, //cdn.shopify.com/s/files/1/1935/4371/products/94175_reducer_corrector_01_medium.jpg?v=1603736883, Popular Science by Celestron StarSense Explorer DX 5" Smartphone App-Enabled Schmidt Cassegrain Telescope, Advanced VX 8" Schmidt-Cassegrain Telescope, C9.25 Optical Tube Assembly (CGE Dovetail), Advanced VX 6" Schmidt-Cassegrain Telescope, Advanced VX 700 Maksutov Cassegrain Telescope, CGX-L Equatorial 925 Schmidt-Cassegrain Telescope, CPC 1100 GPS (XLT) Computerized Telescope, CGX-L Equatorial 1400 Schmidt-Cassegrain Telescope, CGX-L Equatorial 1100 Schmidt-Cassegrain Telescope, CGX Equatorial 925 Schmidt-Cassegrain Telescope, CGX Equatorial 800 Schmidt-Cassegrain Telescope, CGX Equatorial 1100 Schmidt-Cassegrain Telescope, CGEM II 1100 Schmidt-Cassegrain Telescope, Advanced VX 9.25" Schmidt-Cassegrain Telescope, Advanced VX 11" Schmidt-Cassegrain Telescope, Not compatible with #93648 Off-Axis Guider, not compatible with #93519 2" Mirror Diagonal (discontinued), Currently not compatible due to mechanical interferences. 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. Most Feather Touch focusers cost between $300-$350. This is a. 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. These reducers can also be used for visual observing with SCT scopes with eyepieces with a field stop as large as 24-27mm. Focal Reducers | Celestron If you want to save a few buck watch the classifieds on CN. However, some focal reducers can be used on other models of telescopes, but this is not always possible. I have had the Japan unit on the back of my C5 since 1994 or thereabouts. Possibly the design of the Antares was changed .. Each focal reducer has a fixed specification called the working distance or required back focus. 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. 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. Celestron Reducer Lens .7x - EdgeHD 925 The EdgeHD .7x Focal Reducer Lens makes your EdgeHD 925 one full F-Stop faster than f/10, reducing your exposure time by half to capture the same brightness of object 5-element lens design Maintains similar. Try & buy if you like - usual mates rates. Focal reducers for refractors are easy to use. Upon close inspection, it was clear that the housing of Antares assembled in Canada version was a little more substantial than the Celestron. These reducers have a back focus (or design working distance) of 80mm. Download the Celestron PWI Telescope Control Software. Style: The stock Celestron visualback is just under 2 long. Increase that distance, and greater reduction results and visa versa. Nowadays I tend to use the Celestron more with my refractors for imaging and viewing. Not a bit. Reducer - Corrector | Celestron If it's positioned further from the eyepiece or camera and closer to the telescope objective, the reduction factor increases. The previous post shows the reducer on what appear to be two different refractors. Now It only focuses near things, like some kind of macro zoom. 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. More important, its clear that the Antares is a reducer/corrector, just like the Celestron and not merely a reducer. This factor is designated by a power that is less than 1, and it usually lies between 0.5x or 0.8x. This focal reducer is made to attach to the rear cell of Schmidt-Cassegrain or Maksutov-Cassegrain telescopes. But in the end they both do pretty much the same thing and it sounds like any performance difference is subtle. What an enjoyable read and detailed comparison. 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. F 6.3 focal reducer/corrector. - Discussions - Stargazers Lounge For the best experience on our site, be sure to turn on Javascript in your browser. 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. Normal shipments will resume on Monday, March 6, 2023. nleash the full pointing accuracy of your Celestron computerized telescope with a specialized telescope control software suite. I've seen some older threads saying that the Celestron, Meade and Antares FRs are all the same and manufactured in the same factory. How does it look thats what matters. They are designed (assuming you are referring to the f/6.3 version) for the f/10 light cone. The Celestron f/6.3 is ~150 compared to the Antares at ~70. Planetarium software package which provides easy-to-understand explanations and impressive visuals of all kinds. 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. It also leads to larger (although fainter) images of extended objects like the Moon or planets for astrophotographers or visual observers. Antares Click Lock Visual Back - Cats & Casses - Cloudy Nights That includes, for example, a 1.25" eyepiece with an apparent field of view of 68 and a focal length of 24mm (eg. Reducer Lens .7x - EdgeHD 800 Perhaps not exactly- there will be some uncertainty because of manufacturing tolerances and so forth, but it will be close. Some coma is visible in the corners, but the image is quite good for EAA applications. In many cases, the answer is yes, especially for electronically-assisted astronomy (EAA). There is one difference though the Antares came with only one lens cap whereas the Celestron had a cap for both ends. 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. and you will be fine. We have tested our current batch and it works with Meade, Celestron, and Baader SCT accessories. Any comments gratefully received. This filter threads on to the rear cell of your Celestron or Meade SCT telescope. So it provides a 0.63x design reduction factor when used with an f/10 SCT at the specified working distance. - thanks. This part is no longer in production, but it is sometimes available used and may be used with cameras with smaller sensors. Manish Panjwani has been an active amateur astronomer since before Halley's Comet last flew by our neighborhood. Sign up for our newsletter to get exclusive deals, observing tips, and new product announcements. 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. However, these will not impact optical performance. Free shipping $189.95 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 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). 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. All Rights Reserved. control and Sky Viewer display makes selecting your target easy. That's partly because focal reducers correct for field curvature, which itself depends on the focal ratio and other optical design factors of the telescope. WiFi technology encircles the globe in a web of connectivity, knowledge, and information. Meade once made an f/3.3 focal reducer for SCT scopes. Place the plastic covers on the lens when not in use to reduce the dust collection. The reducer features fully coated optics in an anodized aluminum filter ring with an ergonomic rubber grip. In practice, it's important to remember that you will rarely operate at the exact working distance and at the exact reduction factor that is specified. The female end attaches to the rear cell of the telescope. Meade once made an f/3.3 focal reducer for SCT scopes. Maybe I got a lemon. 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? No retailers currently carry this product. 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. The internal surfaces are blackened and glare-threaded to provide the highest contrast. 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. 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. Also read the reviews here, including those at 4 stars. As per the OP I still can't see any reason to buy the Celestron for significantly more $$$. The equations in the Appendix show how this all works. This focal reducer and field flattener consists of a four-element multicoated 40mm lens in a metal cell. If the reducer is placed elsewhere, at a position called the operating distance, the focal reduction factor will not be as advertised. 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. JavaScript seems to be disabled in your browser. These scopes are compatibles with focal reducers. 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. It must be in stock at the time of Price Match for us to make a guarantee. Antares f/6.3 Focal Reducer for Schmidt-Cassegrain Telescopes - Agena Astro 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 Celestron f/6.3 is ~150 compared to the Antares at ~70. My application is mostly visual now, but I'm looking to do more astrophotography over time. Does anyone know if the Antares 4000 focal reducer is as good as the Celestron focal reducer. But the diameter of the image circle decreases by a factor of 0.63 to about 24mm. control and Sky Viewer display makes selecting your target easy. Fumbling around in the dark, fine threads might be a problem. I've looked through one from Meade and first impression was that it was like the Celestron version. The C8 has no noticeable vignetting with a 32mm Plssl in the f/6.3 reducer. However, this also came at a cost, as the sky background in the Antares was slightly brighter. So ab6110 is asking for a FR only without coma correction, there are a couple of brands who make special reducers for the ACF. 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. By Your eyepieces are the first accessories you should learn to use with your telescope. Please let us know what topics you are interested in. The equations and argument in the Appendix of this article shows the relationship between the working distance and the reduction factor. 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. With the barrel 1.25 reducer won't focus, all I get is fuzzy snowballs. A useful thing to know is how far from the objective lens (for a refractor) is the focal reducer located. Field stop diameters are one of the specified specs of eyepieces. 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. Never noticed any anomalies with this unit. 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. 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. First, I wanted to compare the actual reduction provided by these competitors, as many threads here cite different ideal spacing from the reducer to eyepiece focal plane to achieve the correct f/6.3 result. They are also less expensive than many external focusers of similar build quality. That is definitely a 2" eyepiece, but it is not a large or long focal length 2" eyepiece. And when used in some refractors, the field flattening is not as accurate as it is in the f/10 SCTs. Copyright 2003-2022 Agena AstroProducts. I have an 8SE, and am thinking about getting a focal reducer. I have a made in Japan 6.3 R/C and a made in China 6.3 R/C.

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