The stars at the edge could be worse or better. 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. Maybe I got a lemon. Sign up for a new account in our community. 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. 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. This focal reducer and field flattener consists of a four-element multicoated 40mm lens in a metal cell. JavaScript seems to be disabled in your browser. The Reduction Factor and the Amount of Reduction are inversely related. More aggressive reduction, or using these reducers with larger sensors, will result in aberrations and distortions near the edge of the image. 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. WiFi technology encircles the globe in a web of connectivity, knowledge, and information. My experience is that CN sellers are way above those listing elsewhere. 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. 3. ), 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. 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. One of the most important factors in a telescope is its transmissionthe percentage of light that reaches the focal plane. It's easy! 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. Any comments gratefully received. Perfect for the serious student, professional scientist and discriminating hobbyist. Thank you so much for the informative article, I now understand better how to integrate my reducer into my system to get better performance. if the illuminated field is 27mm wide without the reducer, it will be 27 x 0.63 = 17mm with it in place. 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. Unlike . They are commonly available in 1.25" and 2" threaded cells that conveniently thread into the nosepiece of a compatible camera or the barrel of an eyepiece. a Tele Vue Panoptic), or a Plossl eyepiece with an apparent field of view of 50 and a focal length of 32mm. 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). Thanks guys, appreciate the feedback. This is a. 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 focal length and design working distance for this focal reducer were not available from the manufacturer. In terms of reduction and correction which are what reducer/correctors are supposed to do both are superb. The two samples I have PERFORM IDENTICALLY. Free shipping $189.95 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. JavaScript seems to be disabled in your browser. In some cases, focal reducers also act as field flatteners by correcting for field curvature and coma of the objective lens. Product Details. Yet, the Antares still easily and fully threaded without any hitches. Equation 6 & 7 item two & three does not make sense, both say increase its reduction (one should say reduce its reduction?). However, even though the imprint on the item states "Reducer / Corrector" please note that his is a reducer only. There are also third-party vendors such as Hotech. Because most modern Newtonians already have relatively fast focal ratios, these telescopes do not usually use focal reducers. Focal reducers for refractors are easy to use. It's usually specified from the base of the mounting threads on the reducer's housing, and this is the most practical way of providing this specification. I happily cycle through LRGB filters to build the image rather than do a whole run of one filter at a time. 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. In many cases, the answer is yes, especially for electronically-assisted astronomy (EAA). Reducer Lens .7x - EdgeHD 800 Meade once made an f/3.3 focal reducer for SCT scopes. 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. But when not in the box or on the telescope, there is no cover for the other end. The new Lithium Phosphate (LiFePO4) battery chemistry has significant advantages over other battery chemistries, great for for those Astronomers on the go. Can you help me? For the best experience on our site, be sure to turn on Javascript in your browser. 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. You don't need to follow these equations to use a focal reducer, but they do show how the reduction factor changes with the placement of the reducer. All additional accessories mount onto the exterior/male threads. It works fine but you should stick with 1.25 EPs; or can use 2" EPs without corrector. 2023 OPT Telescopes. Many Ritchey-Chretien telescopes available today are made by GSO. Such an image circle is still large enough to encompass the relatively large sensor of many deep-sky astronomy cameras. Please let us know what topics you are interested in. 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. You may need spacers or a T-adapter to ensure the correcting working distance. As another example,GSO makes focal reducers for their line of Ritchey-Chretien imaging telescopes. Reproduction without permission prohibited. because they really dont matter. CPWI has an extensive object database, employs PointXP mount modeling, and more. 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. 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 equations in the Appendix show how this all works. We have corrected # (iii) after equations 6 & 7. Again, these focal reducers are often provided by the telescope manufacturer. . This innovative software solves the time-consuming problem of trying to pinpoint the North Celestial Pole. Possibly the design of the Antares was changed .. The lens that the ZWO comes with give a perfect wide angle image of what is in front of it. 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. My application is mostly visual now, but I'm looking to do more astrophotography over time. The Antares focal reducer comes in small box. This is one of our best-selling items, and customers have reported that this product is at least as good as, and probably better than, other leading f/6.3 focal reducers sold on the market for a lot more. This also resulted in the clear aperture of the Antares being about 39-39.5mm, versus the Celestrons 41mm. First, let's have a look at some key optical parameters are needed to understand focal reducers. At least these two units I tested make the answer - whatever. 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. Can you tell me about the use of reducers in Maksutov-Cassegrain telescopes? This Antares 1.25" 0.5x focal reducer lens (tele-compressor) is used under the Orion brand name to thread into the nosepiece of Orion StarShoot Solar System cameras and StarShoot Deep Space Color Imaging Camera. 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. That was fun. 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. 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. I have a made in Japan 6.3 R/C and a made in China 6.3 R/C. The Best Dedicated Astronomy Cameras for Beginners, Astronomik OIII 12nm CCD Filter - T-Threads, Pegasus Astro Dual Motor Focus Controller, 10 Micron 12kg (26.45lbs) Stainless Steel Counterweight- GM 2000, I would like more information regarding stock availability dates. Celestrons patented StarSense Technology makes it easier than ever to locate objects in the night sky, even if youve never used a telescope before. All Rights Reserved. All rights reserved. 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. If it's positioned further from the eyepiece or camera and closer to the telescope objective, the reduction factor increases. For this test, I used a single configuration R/C, Click-lock, and 1.25 diagonal with the adapter. 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. Celestron or Antares f/6.3 focal reducer for SCT? 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. It has only one cover, which surprised me. 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). Nada. Newtonian reflectors will seldom be able to accommodate the in-focus travel demanded by focal reducers. Reducer Lens .7x - EdgeHD 925 Reducer - Corrector DUE TO EXTREMELY HIGH DEMAND, WE WILL NOT BE TAKING NEW ORDERS UNTIL MONDAY, DECEMBER 14. 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 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. 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. An eyepiece with a 27mm field stop yields a true field of 1.03 in the C6 at f/10. Once installed, you can add additional accessories like T-Adapters, 1.25 Visual Back, Star Diagonal, or Off-Axis Guider. I focus using a moonlight electronic focuser and focusmax. Looking forward to the day when I can do a shoot-out between a Japan and China Celestron, just for kicks. However, it will not thread into William Optics accessories, and with GSO it is a hit or miss. If you want to save a few buck watch the classifieds on CN. Copyright 2003-2022 Agena AstroProducts. The equations and argument in the Appendix of this article shows the relationship between the working distance and the reduction factor. Celestron Nexstar+ 127 SLT, several budget plossl eyepieces, Celestron 8-24mm zoom EP and a 12.5mm illuminated double reticle EP, Svbony SV205 camera w/.5 focal reducer, Celestron SkyMaster 20x80 binos on a 40 yr old QuickSet PanHead tripod, Stellarium, Sharpcap and ManyCam on my laptop, SkyView and Nightshift on my phone and a dandy little $9 . We reserve the right to verify a competitor's advertised price and the availability of the item. 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. 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. But is there a difference in quality between the Antares and the Celestron or Meade focal reducers? Today, our world-class team of optical and electronic engineers continues to push the boundaries of technology. But in the end they both do pretty much the same thing and it sounds like any performance difference is subtle. Explore Scientific Keys to the Universe Sale, Antares f/6.3 Focal Reducer for Schmidt-Cassegrain Telescopes, Skip to the beginning of the images gallery. 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. Your mileage may vary. In both cases will end with a similar tfov. riklaunim Members 559 3,445 Location: Poland Posted October 11, 2010 They are reported as identical. 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. The price for an item/offer must be listed and valid at the time of match. If used before or beyond the working distance, unwanted image distortion may result. 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. Sign up for OPT news, exclusive offers, and updates on the latest gear! 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 previous post shows the reducer on what appear to be two different refractors. 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. 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. Field stop diameters are one of the specified specs of eyepieces. Have a promo code? 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. Copyright 2003-2022 Agena AstroProducts. For visual use, this means you get lower power with the same eyepiece and a wider field of view. 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. No negative issues to report. Many focal reducers for refractors have a working distance (or back focus distance) of 55mm. Obviously bright objects like Jupiter or The Moon show the reflections. With both, using the same diagonal set-up, the exact same stars were visible at the very edge of the FOV. Easy solution found a very tiny dab of super lube on the threads and all was well and quiet.. All rights reserved. I even lost track of which reducer I was using. 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. Very helpful, thanks a lot for this article! Hi. Some coma is visible in the corners, but the image is quite good for EAA applications. If you place your camera at a different working distance, you will get a different reduction factor and perhaps unwanted distortion in the image. That is definitely a 2" eyepiece, but it is not a large or long focal length 2" eyepiece. M44 was a perfect target for this, as its large size maxes out the FOV on a C8 with a corrector, and its bright stars make great targets for measuring the very edge of the visible field. Like you, I am primarily visually observing but I have everything together now that so I am going to start experimenting with photography so we'll see how it does there. None of this was offensive, nor did it interfere with views in any significant way. As per the OP I still can't see any reason to buy the Celestron for significantly more $$$. Quite interestingly it bears the very same engravings of the Meade 4000 r/c (including "series 4000") except for "MEADE". In the 1960s, Celestrons founder, Tom Johnson, created groundbreaking new telescopes never before seen on the consumer market. 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. Style: The Celestron f/6.3 is ~150 compared to the Antares at ~70. This should not be the case if they have their purportedly different focal lengths. We do not price match competitors if they are out of stock. Regardless, the difference was miniscule and is more than adequate on both and exceeds a 8 or 6 SCTs baffle tube diameter. This filter threads on to the rear cell of your Celestron or Meade SCT telescope. 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. It must be in stock at the time of Price Match for us to make a guarantee. The threads were similar on the eyepiece end, but a bit smoother. Can these economical focal reducers from GSO and other vendors result in good images? The most popular accessories for your new telescope! 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. 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. However, because the field curvatures in refractors and SCTs vary a lot, I would predict unpredictable effects inre: field curvature. There is a way to make subjective data more useful and that way is proper blind, or better still. 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. 2. In some cases, focal reducers also act as field flatteners by correcting for field curvature and coma of the objective lens. But I am rusty, can you condense a bit for me please? Steve 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. Sharpness is essentially the same. 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. 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 . A useful thing to know is how far from the objective lens (for a refractor) is the focal reducer located. Oceanside Photo & Telescope wants our customers to shop with confidence knowing that you will always get the best deal available. Reducer Lens .7x - EdgeHD 1400 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.
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