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Our proprietary StarBright XLT optical coatings dramatically increase transmission, up to 97.4% on our Schmidt corrector lenses. 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. I have a Raspberry HQ camera, a Sony TV Zoom 12.5-75mm f1.8 and a Astromania 1,25" 0.5x focal reducer. Specially-designed focal reducers are available for use with these telescopes. Easy solution found a very tiny dab of super lube on the threads and all was well and quiet.. 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. a Tele Vue Panoptic), or a Plossl eyepiece with an apparent field of view of 50 and a focal length of 32mm. Once focused it's pretty good. I think that the FRs made in Japan in the day may have been better. I have an 8SE, and am thinking about getting a focal reducer. If you place your camera at a different working distance, you will get a different reduction factor and perhaps unwanted distortion in the image. 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. Check out our 2022 telescope buying guide here! He also holds a Ph.D. in engineering physics from McMaster University. Hi. If it's positioned further from the eyepiece or camera and closer to the telescope objective, the reduction factor increases. Well done. Reducer - Corrector Learn More. control and Sky Viewer display makes selecting your target easy. I wont bother with differences in packaging, caps, etc. In some cases, focal reducers also act as field flatteners by correcting for field curvature and coma of the objective lens. Place the plastic covers on the lens when not in use to reduce the dust collection. 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. By Easy solution found a very tiny dab of super lube on the threads and all was well and quiet. That includes, for example, a 1.25" eyepiece with an apparent field of view of 68 and a focal length of 24mm (eg. 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. I have a made in Japan 6.3 R/C and a made in China 6.3 R/C. If used with other f/ratios, the field flattening characteristic may be unpredictable. Because I have not heard any complaints about the made in China R/C. Explore Scientific - Keys to the Universe Sale. Copyright 2003-2022 Agena AstroProducts. 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. They provide 0.75x focal reducers for these telescopes that takes an f/8 instrument down to f/6. This means that there must be sufficient travel on the telescope focuser to make up for this. 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. 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. 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. To test this, I used three set-ups: 1. They only publish the value of D, the working distance (sometimes called the back focus distance) and the design reduction factor MRD. 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. If the reducer is placed closer to the eyepiece or camera than the distance D, the reduction factor decreases. looks virtually identical, except for the lettering. The working distance or required back focus, explained above, is usually specified and is far more important in practice. You currently have javascript disabled. Does anyone know if the Antares 4000 focal reducer is as good as the Celestron focal reducer. Photographically you also get a wider field and much shorter exposures. Style: Can you help me? 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. As another example,GSO makes focal reducers for their line of Ritchey-Chretien imaging telescopes. Images made with my ZWO 533 camera testing both show them to be essentially the same. 800-483-6287 Theres a long-running debate in these forums and even statements from some reputable dealers that the Antares is just a reducer (even though it is labeled Reducer/Corrector), whereas the Celestron is a true R/C, which flattens the SCTs naturally curved field and provides some edge correction. We have corrected # (iii) after equations 6 & 7. Try & buy if you like - usual mates rates. The nominal design reduction factor of these reducers is typically 0.5x. I own both and concur heartily. Despite never removing it no matter what I was looking at. We will be glad to help. I also used several eyepieces including the ES 24mm/68, 17.5mm and 12.5mm Morpheuses, and a 10.5mm Pentax XL. We do not price match competitors if they are out of stock. I would not use the reducer with a 2" diagonal or eyepiece in the C6. And, the reality is that every F/6.3 RC out there Celestron, Hirsch, Astromania, etc., etc. It also leads to larger (although fainter) images of extended objects like the Moon or planets for astrophotographers or visual observers. Is that distance D= Fo-d1=Fo-(d2/MR)? The review is a subjective visual impression, which is interesting but not best evidence. Start Chat 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. 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. For me, I was looking for, and planning to keep, the one that yielded the greatest reduction. Reducer - Corrector which looks like the same one. Quite interestingly it bears the very same engravings of the Meade 4000 r/c (including "series 4000") except for "MEADE". 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. I've only used it a few times but it looks good to me. Thanks. I had a Celestron, Antares and Hirsch for awhile and compared them over about a year. Go behind the scenes with Celestrons product development team and learn more about our award-winning and patented innovations. Hmmm . October 11, 2010 in Discussions - Scopes / Whole setups. The Antares is supposed to be pretty comparable. 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. 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. Increasing the operating distance, that is, moving a focal reducer away from the eyepiece or camera reduces its reduction factor, or conversely increases the amount of reduction. Read our 101 article or get in touch. 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. As one increases, the other decreases. Another factor to consider: focal reducers also increase the angle at which light approaches the focal plane. The internal surfaces are blackened and glare-threaded to provide the highest contrast. 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. Reducer Lens .7x - EdgeHD 1100. 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. Celestrons award-winning Nature DX binocular gets a major upgrade with the addition of ED objective lenses. 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. 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? 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. Who cares? I think I remember hearing the reduction factor is slightly different, cant remember more or less reduction. These 0.63x focal reducers were originally designed to optimize for an image circle to match 36mm x 24mm film or its digital equivalent for astrophotography. 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. One focal reducer will not achieve optimum results with all types of telescopes, so there is no universal' focal reducer. ED stands for "extra-low dispersion," which refers to the composition and optical properties of the glass used for the lenses. Many focal reducers are meant to be used within a few millimeters of the specified working distance to achieve the best possible image results. 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. 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. Does anyone know if the Antares 4000 focal reducer is as good as the Celestron focal reducer. Celestrons FREE planetarium app is an astronomy suite that redefines how you experience the night sky. This article explains the basics of how focal reducers work with an astronomy telescope. Celestrons aplanatic EdgeHD optics revolutionized astroimaging. It is recommended for . 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. Designed distancing using the reducer with a 1.25 visual back and 1.25 Televue mirror diagonal; The price for an item/offer must be listed and valid at the time of match. 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. It was used strictly for imaging, not visual observing. . 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. It must be in stock at the time of Price Match for us to make a guarantee. Maybe I got a lemon. Optically, it consists of a four-element lens that is fully multi-coated for high contrast and resolution. Celestron is considered better in terms of QA, less likely to come with free dust, hair or fingerprint. - thanks. 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. Focal reducers for many SCTs and their flat-field equivalents usually have a back-focus distance of 105mm. 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. 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. In such cases, we will be happy to take the item back as per our standard return terms. 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. 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 Due to the design, the Reducer/Corrector lens does diminish a small amount of field curvature common to all Schmidt Cassegrain telescopes but does not eliminate it. The distances d1 andd2 can also be expressed in terms of the focal length of the focal reducer FR with the lens equation: Using Equation 2, Equation 1 can also be expressed in terms of d2: The focal reduction factor of the focal reducer depends on its focal length and its distance from the focal plane of the objective as shown by Equation 4: Again, for example, when the focal reducer is placed at the original focal plane of the objective, d1=0 and MR=1, which means there is no focal reduction. Can you tell me about the use of reducers in Maksutov-Cassegrain telescopes? So, this past week I challenged the Antares and Celestron models to a head-to-hear on my C8 on some decent nights of good seeing and transparency in my Bortle 5-6 urban skies. During check-out, you will be presented with several shipping choices and costs. Not one detectable iota of discernable difference. because they really dont matter. If used before or beyond the working distance, unwanted image distortion may result, especially when using cameras with larger sensors. One problem with getting opinions is that most of use do not have both reducers or have never done a side by side comparison. If yes, what kind of focal reducers can I use? The lens that the ZWO comes with give a perfect wide angle image of what is in front of it. It has only one cover, which surprised me. Right off the bat, I was struck by how similar the two R/Cs were. My Celestron was made in China and the Antares in Canada. Assuming you use the reducer with the stock 1.25" diagonal, it will operate at f/6.3. The Buyer's Guide To Eyepieces at the top of the Eyepieces forum has a column for this spec. Many Ritchey-Chretien telescopes available today are made by GSO. 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. In many cases, the answer is yes, especially for electronically-assisted astronomy (EAA). 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. 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. I have had the Japan unit on the back of my C5 since 1994 or thereabouts. I have both the Antares and the Celestron reducers. The new Lithium Phosphate (LiFePO4) battery chemistry has significant advantages over other battery chemistries, great for for those Astronomers on the go. In most cases, the easiest option is to choose the focal reducer made specifically for your telescope. 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. Reducer Lens .7x - EdgeHD 925 Learn More. Focal reducers for these relatively fast ED refractors are generally for imaging only, not for visual observation. 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. A slight nod to the Antares for heft and higher transmission, but points to the Celestron for nice threads and better contrast. All rights reserved. A focal reducer does just the opposite of a Barlow lens or focal extender. We have tested our current batch and it works with Meade, Celestron, and Baader SCT accessories. An f/6.3 reducer is designed to reduce the focal ratio of an f/10 SCT to f/6.3. When the camera sensor is placed at this distance, the reduction factor of these reducers is 0.75x. More important, its clear that the Antares is a reducer/corrector, just like the Celestron and not merely a reducer. If I had to guess, the difference is maybe 10-15 grams. If you do so, you will achieve the design reduction factor. For example, an 8" SCT without a focal reducer has an illuminated field of 38mm at 50% fall-off. 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. Fortunately, my neighbors are not out in their backyards at 11 pm, or they may have thought I was torturing a small mammal. I use it on my C8 SCT with a 1000d, and it seems to do everything written on the tin. Focal reducers also move the effective focal plane of the objective inward, that is, towards the objective (see Figure 1). With spring galaxy season here, I decided to pick up a couple more to compare in a head-to-head shoot out. 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. If the reducer is placed elsewhere, at a position called the operating distance, the focal reduction factor will not be as advertised. The two samples I have PERFORM IDENTICALLY. 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. They are also less expensive than many external focusers of similar build quality. Sign up to get exclusive deals, observing tips, and new product announcements. As a real-world example plot showing the above relationships, let's look at the 1.25" GSO focal reducer that provides a design reduction factor of 0.5x. With the Celestron Reducer/Corrector Lens, thats precisely what you get. Your mileage may vary. Now, Celestron is using that same technology to allow star gazers to connect to the night sky and enhance their experience of the cosmos in fun and unique ways. 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. ), but stars seemed a bit tighter and their colors were richer and more dramatic. 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. Reducer Lens .7x - EdgeHD 925 Enter it during checkout! Brian Ventrudo is a writer, scientist, and astronomy educator. No small animals were harmed in making these observations. 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. It seems right to put some distance between the camera and the focal reducer, right? Reproduction without permission prohibited. No retailers currently carry this product. This focal reducer and field flattener consists of a four-element multicoated 40mm lens in a metal cell. If you want to save a few buck watch the classifieds on CN. 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. These scopes are compatibles with focal reducers. 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). 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. The Antares focal reducer comes in small box. However, this also came at a cost, as the sky background in the Antares was slightly brighter. Sign up for our newsletter to get exclusive deals, observing tips, and new product announcements. However, the export of some items may be restricted outside the US due to size or manufacturer restrictions. What an enjoyable read and detailed comparison. 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. The stars at the edge could be worse or better. Equation (4) shows the relationship between the distance d2 and the reduction factor MR. 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. Better images are also obtained when using these focal reducers at a reduction factor of 0.5x 0.8x, approximately. Sign up to receive sale alerts, news about upcoming celestial events, and telescope tips from our experts! My experience is that CN sellers are way above those listing elsewhere. They never really recovered from selling a few 15 years back with element reversed. Description. This is very impressive performance given how hard this problem is to mitigate in general. This factor is designated by a power that is less than 1, and it usually lies between 0.5x or 0.8x. I must admit, as well, that I no longer place a lot of stock in the notion that Chinese optics are inferior to Japanese or Taiwanese any longer, as manufacturing technology has really leveled the playing field today, with most Chinese optics being excellent. 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. However, because the field curvatures in refractors and SCTs vary a lot, I would predict unpredictable effects inre: field curvature.