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Any comments gratefully received. However, doesn't fit in the telescope and even if it did wouldn't work. This article explains the basics of how focal reducers work with an astronomy telescope. Focal reducer for 8SE - Celestron vs. Antares - Cloudy Nights . The stock Celestron visualback is just under 2 long. The threads were similar on the eyepiece end, but a bit smoother. Reducer - Corrector Learn More. Bear in mind you can't squeeze blood out of a turnip, i.e. 3. Never noticed any anomalies with this unit. Start here to find the perfect telescope for you! We have corrected # (iii) after equations 6 & 7. 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. Michael 1 ronin Members Brightness, color, and contrast were subtly different, but could be as much the day they were coated as any real difference in the two brands. Reproduction without permission prohibited. Celestron or Antares f/6.3 focal reducer for SCT? The Reduction Factor and the Amount of Reduction are inversely related. Best evidence would by obtained by using a camera and evaluating the image both by eye and with a computer analysis. However, even though the imprint on the item states "Reducer / Corrector" please note that his is a reducer only. Sharpness is essentially the same. 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. 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. Watch this before you buy Celestron 8SE SCT, or a Focal Reducer or a Many focal reducers for refractors have a working distance (or back focus distance) of 55mm. Learn more about extra solar planets imagery, 3D Star rendering, observation planning, telescope control, multiple-panel printing, and much more. Imaging - Focal Reducers and Flatteners - Page 1 - KW Telescope No rainchecks will be issued for items out of stock at OPTcorp.com to match a competitor's price. In some cases, focal reducers also act as field flatteners by correcting for field curvature and coma of the objective lens. Explore Scientific Keys to the Universe Sale. ED stands for "extra-low dispersion," which refers to the composition and optical properties of the glass used for the lenses. The working distance or required back focus, explained above, is usually specified and is far more important in practice. Stars in the corner of the image frame are indistinguishable between the Antares and the Celestron. The reducer is we might presume designed to correct to some as yet un-measured extent, the image of a standard SCT. Free shipping $189.95 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. It was also a little brighter in the center of the field with subtle darkening in the outer 20% or so. By For me, I was looking for, and planning to keep, the one that yielded the greatest reduction. Several functions may not work. Orders placed after 12:00 PM Pacific Time will be shipped the next business day. But in the Japan version I have never noticed any anomaly like the ghosting in the China R/C. 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. Completely stuck, completely frustrated. How about for visual observers? One of the most important factors in a telescope is its transmissionthe percentage of light that reaches the focal plane. 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. DUE TO EXTREMELY HIGH DEMAND, WE WILL NOT BE TAKING NEW ORDERS UNTIL MONDAY, DECEMBER 14. This focal reducer is made to attach to the rear cell of Schmidt-Cassegrain or Maksutov-Cassegrain telescopes. But nearly every observer who installs one of these devices is pleased with their performance. 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. Edited by Tony Bonanno, 16 April 2021 - 06:44 PM. I really don't see any difference in the current crop except the "Meade" is usually the cheapest. A longer effective focal length leads to higher magnification with a given eyepiece for visual observers. 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). These scopes are compatibles with focal reducers. This is the simplest way to attach your ASI121 to your telescope. The previous post shows the reducer on what appear to be two different refractors. If you do so, you will achieve the design reduction factor. I have Hirsch focal reducer, which is yet another clone of the Celestron reducer. I own both and concur heartily. All additional accessories mount onto the exterior/male threads. I have had the Japan unit on the back of my C5 since 1994 or thereabouts. 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. No retailers currently carry this product. 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. We reserve the right to verify a competitor's advertised price and the availability of the item. Astro-Tech Schmidt-Cassegrain f/6.3 Focal Reducer Field Flattener If used with other f/ratios, the field flattening characteristic may be unpredictable. More details are found in the Appendix of this article. control and Sky Viewer display makes selecting your target easy. because they really dont matter. Clean, fun jokes the tradition continues - Page 106 Celestron Solar Safe filter technology is GUARANTEED SAFE for direct solar observation and has been independently tested by SAI Global Assurance Services. These reducers have a back focus (or design working distance) of 80mm. Agena's Guide to Focal Reducers - Agena Astro The internal surfaces are blackened and glare-threaded to provide the highest contrast. Obviously bright objects like Jupiter or The Moon show the reflections. I use the same back spacing for both on a small 6" Celestron SCT. Clearly cost is a big factor for satisfied users. No idea what the issue is. Celestrons aplanatic EdgeHD optics revolutionized astroimaging. None of this was offensive, nor did it interfere with views in any significant way. 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. Sign up for our newsletter to get exclusive deals, observing tips, and new product announcements. 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. Unleash the full pointing accuracy of your Celestron computerized telescope with a specialized telescope control software suite. I would not use the reducer with a 2" diagonal or eyepiece in the C6. The distance d2, which measures the position of the new focal plane of the objective from the back of the focal reducer is given by Equation 5: In these equations, d1, d2, and MR are all variables that depend on each other through Equations 2 and 4. However, the China 6.3 R/C has noticeable internal reflections that I haven't figured out yet. My experience is that CN sellers are way above those listing elsewhere. Many reducers, such as the Celestron HD focal reducer mentioned above, and many focal reducers for apochromatic refractors, are meant to be used within a few millimeters (or less) of the specified working distance to achieve the best possible image results. All Rights Reserved. You need to be a member in order to leave a comment. It's usually specified in millimeters. Have a promo code? Shipping will be via the cheapest shipping method which will vary depending on the items in your order. 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. Thanks for the extremely valuable article. To calculate how much back focus spacing you need to add, take the thickness of the filter and divide it by 3. As I understand it, compared to the old Meade SCT's, the ACF is already "coma corrected", so the standard Meade, Celestron etc F6.3 focal reducers are not suitable and will only worsen the images. 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. Yellow and orange members of open clusters stood out a bit more as the various stars displayed their individuality. Possibly the design of the Antares was changed .. For this shoot-out, I used a standard Celestron C8 with Starbright coatings. Once installed, you can add additional accessories like T-Adapters, 1.25 Visual Back, Star Diagonal, or Off-Axis Guider. No negative issues to report. They both are great and I doubt my eyes could detect a difference in any one of them including the Japan version. Your mileage may vary. So Celestron buyers like Celestron, Meade buyers like the Meade and Antares buyer like the Antares. My Celestron was made in China and the Antares in Canada. We have placed cookies on your device to help make this website better. Style: 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. The C8 has no noticeable vignetting with a 32mm Plssl in the f/6.3 reducer. which looks like the same one. Increase that distance, and greater reduction results and visa versa. . So it provides a 0.63x design reduction factor when used with an f/10 SCT at the specified working distance. The most popular accessories for your new telescope! if the illuminated field is 27mm wide without the reducer, it will be 27 x 0.63 = 17mm with it in place. Torazz 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. The faster f/ratio allows you to use slower film or shoot in lower light level situations and still properly expose your subject. 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. Reviews. Get ready for a night of astroimaging with your mount faster than previously thought possible with All-Star Polar Alignment. But I am rusty, can you condense a bit for me please? 0.63x Starizona Focal Reducer for SCTs- Awesome Astrophotography You can adjust your cookie settings, otherwise we'll assume you're okay to continue. A f/10 focal ratio now achieves a f/6.3, while an f/11 focal ratio now achieves a f/7. You can probably eke out 1.2 without noticing serious vignetting, which is a field stop of 31.5mm. 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. F 6.3 focal reducer/corrector. - Discussions - Stargazers Lounge Sign up to receive sale alerts, news about upcoming celestial events, and telescope tips from our experts! 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. That said any comparison reviews are helpful. Specially-designed focal reducers are available for use with these telescopes. Orders placed over the weekend will be shipped on the following Monday. 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. Oceanside Photo & Telescope wants our customers to shop with confidence knowing that you will always get the best deal available. 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 It must be in stock at the time of Price Match for us to make a guarantee. He tested this on an 8 Celestron , I have a Celestron 6SE. 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. Copyright 2021 Stargazers Lounge 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). I only have the Celestron f/6.3. It can also be used with any other small chip CCD camera having a 1.25" nosepiece, such as the Celestron NexImage, Meade DSI . 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. Thanks Peter! Assuming you use the reducer with the stock 1.25" diagonal, it will operate at f/6.3. Try & buy if you like - usual mates rates. I am a purely visual observer, so will evaluate for visual use only. Reducer - Corrector 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. A useful thing to know is how far from the objective lens (for a refractor) is the focal reducer located. How to Set the Correct Back Focus for Your Telescope (Guide) I have an 8SE, and am thinking about getting a focal reducer. A little longer light path with a 2 Baader click-lock, low profile 1.25 adapter, and the 1.25 diagonal; I think I remember hearing the reduction factor is slightly different, cant remember more or less reduction. 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. 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. All rights reserved. There is a way to make subjective data more useful and that way is proper blind, or better still. That is definitely a 2" eyepiece, but it is not a large or long focal length 2" eyepiece. Nebula Filters. Hello! Sign up for a new account in our community. But is there a difference in quality between the Antares and the Celestron or Meade focal reducers? Can you help me? Does anyone know if the Antares 4000 focal reducer is as good as the Celestron focal reducer. 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. Not a bit. Easy solution found a very tiny dab of super lube on the threads and all was well and quiet. 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. 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). Even though they may have been slightly dimmer, galaxies were a bit easier to tease out of the urban light soup I deal with. But while the image gets brighter, the size of the image circle gets proportionately smaller. 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. By using this site, you agree to our Terms of Use. 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. Melotte 15 - First Process in PixInsight (easy! 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. First, let's have a look at some key optical parameters are needed to understand focal reducers. Manish holds a Master's degree in Electrical Engineering from Virginia Tech and an MBA from the Kellogg School of Management at Northwestern University. With the Celestron Reducer/Corrector Lens, thats precisely what you get. 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. 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. Wow, that is a very detailed discussion! Thanks for pointing this out. Years ago, I bought the Antares version, and moved over to the Celestron. Product Details. I'd favor the Japanese Celestron version over the others that are commercially available. He also holds a Ph.D. in engineering physics from McMaster University. I was referring to the C6 to answer you specifically. It has only one cover, which surprised me. Better images are also obtained when using these focal reducers at a reduction factor of 0.5x 0.8x, approximately. 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. But the smaller image circle means there is a limit to the field stop of an eyepiece that can achieve an unvignetted image. As often noted in reviews and forum threads, Antares products tend to have threads that are a little less precise, and this specimen certainly demonstrated this. 0.5X focal reducer for Celestron, Meade, and Orion CCD imaging cameras This factor is designated by a power that is less than 1, and it usually lies between 0.5x or 0.8x. I've only used it a few times but it looks good to me. Enter it during checkout! This focal reducer and field flattener consists of a four-element multicoated 40mm lens in a metal cell. Designed distancing using the reducer with a 1.25 visual back and 1.25 Televue mirror diagonal; However, manufacturers virtually never provide this specification. Figure 7 shows an example of an image of the Dumbbell Nebula taken with a 1.25" GSO focal reducer at a reduction factor of 0.63x with an 85mm f/7 refractor and a QHY5III-290M camera with a sensor with a 6.4mm 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. Antares Click Lock Visual Back - Cats & Casses - Cloudy Nights I've heard and read all kinds of things about the Antares being only a reducer and not a corrector, etc. 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. The Buyer's Guide To Eyepieces at the top of the Eyepieces forum has a column for this spec. Never used one, but read the reviews here that suggest a coating problem. Reducer Lens .7x - EdgeHD 800 Learn More. 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. Blue Fireball M42 T/T2 Thread Camera Adapter for Prime Focus Photography - 2" # P-06, Celestron T-Ring for Canon EOS Camera # 93419, GSO 2" Crayford Focuser for SCTs - Dual Speed, Length of male SCT thread = 5mm (0.2") but this is preceded by an unthreaded part on the eyepiece side making the total length = 8.8mm (0.35"), Length of female SCT thread = 7.5mm (0.3"). Again, these focal reducers are often provided by the telescope manufacturer. It was used strictly for imaging, not visual observing. The Celestron f/6.3 is ~150 compared to the Antares at ~70. 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. I've looked through one from Meade and first impression was that it was like the Celestron version. All rights reserved. For the best experience on our site, be sure to turn on Javascript in your browser. Edited by bluewater, 05 September 2020 - 11:27 AM. The review is a subjective visual impression, which is interesting but not best evidence. Yet, the Antares still easily and fully threaded without any hitches. Quite interestingly it bears the very same engravings of the Meade 4000 r/c (including "series 4000") except for "MEADE". If used before or beyond the working distance, unwanted image distortion may result. Sign up for our newsletter to get exclusive deals, observing tips, and new product announcements. 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. Both exhibited consistent reduction, identical field flattening, and edge correction properties, and both were high quality optically and mechanically. We process your personal data as stated in our. When using the diagonal, keep the field stops of the eyepieces under 20mm. I have both the Antares and the Celestron reducers. If the reducer is placed elsewhere, at a position called the operating distance, the focal reduction factor will not be as advertised. Copyright 2003-2022 Agena AstroProducts. 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. I use it on my C8 SCT with a 1000d, and it seems to do everything written on the tin. I wish there was. 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. We do not price match competitors if they are out of stock. Nada. I've seen some older threads saying that the Celestron, Meade and Antares FRs are all the same and manufactured in the same factory. Dedicated focal reducers for refractors are intended primarily for imaging, not visual observation. F6.3 Focal reducer for F/10 or higher telescopes, 43mm aperture, 4-Element, Fully Multicoated. However, some focal reducers can be used on other models of telescopes, but this is not always possible. Newtonian reflectors will seldom be able to accommodate the in-focus travel demanded by focal reducers. 3. Most manufacturers provide this specification. You attach the focal reducer to the rear port on a SCT and can keep it covered. However, the export of some items may be restricted outside the US due to size or manufacturer restrictions. In both cases will end with a similar tfov. Reducer - Corrector | Celestron Very helpful, thanks a lot for this article! 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. WiFi technology encircles the globe in a web of connectivity, knowledge, and information. 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. A former wireless communications consulting engineer and management consultant to various Fortune 500 companies, Manish started Agena AstroProducts in 2003. Who cares? EclipSmart solar products feature Solar Safe filter technology providing the ultimate protection from harmful solar radiation, including both IR and UV light, and filters 99.999% of visible light. 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. (Note: Using the simple equations above, the focal length of this reducer can be estimated to be about 350mm).