The telescope side of the barrel is often threaded with an M48 x 0.75 thread for standard 2" astronomy filters. We process your personal data as stated in our. For Ritchey-Chretien telescopes such as those manufactured by GSO, there are also dedicated focal reducers with a reduction factor of 0.7x to 0.8x. 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. Please Log in to save it permanently. What an enjoyable read and detailed comparison. There will be no shipments on 3/1/2023, 3/2/2023, or 3/3/2023 (March 1st - March 3rd, 2023). Just one question. The Celestron f/6.3 is ~150 compared to the Antares at ~70. Does anyone have any experience with the Celestron and Antares focal reducers? Wow, that is a very detailed discussion! Any comments gratefully received. They only publish the value of D, the working distance (sometimes called the back focus distance) and the design reduction factor MRD. Reducer - Corrector 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. The lens is housed in machined aluminum for are machined aluminum black anodized. Benefits limited to hardware and conditions? 2. They provide 0.75x focal reducers for these telescopes that takes an f/8 instrument down to f/6. 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. Despite never removing it no matter what I was looking at. Description. Never used one, but read the reviews here that suggest a coating problem. Orders placed over the weekend will be shipped on the following Monday. I would not use the reducer with a 2" diagonal or eyepiece in the C6. Specially-designed focal reducers are available for use with these telescopes. Completely stuck, completely frustrated. The price for an item/offer must be listed and valid at the time of match. 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). 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. We reserve the right to verify a competitor's advertised price and the availability of the item. There is a way to make subjective data more useful and that way is proper blind, or better still. All additional accessories mount onto the exterior/male 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. Meade and Celestron both sell such SCT-T adapters with the correct optical length. 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. 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. Great for home, classroom, or home-school use, this kit includes all the essential items youll need to begin exploring the wonders of the microscopic world. 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. 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). Another factor to consider: focal reducers also increase the angle at which light approaches the focal plane. 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. 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. My Celestron was made in China and the Antares in Canada. I was originally hoping to do this with a made in Japan Celestron, but ended up with a newer China version but thats probably better in the end since it is the version now available, with the Japan ones rarer and only available used. 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. However, some focal reducers can be used on other models of telescopes, but this is not always possible. . Explore Scientific - Keys to the Universe Sale. Observing the microscopic world has never been easier! In both cases will end with a similar tfov. Rather than a direct side-by-side, I swapped the reducers so that I was using them on the exact same, well-collimated instrument. Celestrons aplanatic EdgeHD optics revolutionized astroimaging. A f/10 focal ratio now achieves a f/6.3, while an f/11 focal ratio now achieves a f/7. The Antares f6.3 focal reducer screws directly to the visual-back thread of all popular SCTs and converts f10 instruments to f6.3. I have a made in Japan 6.3 R/C and a made in China 6.3 R/C. The Reducer/Corrector is easy to install by threading the unit onto the rear cell of your Schmidt-Cassegrain telescope (or the reducer plate of the C11 and C14). The reducer features fully coated optics in an anodized aluminum filter ring with an ergonomic rubber grip. I have an 8SE, and am thinking about getting a focal reducer. 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. 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 more focal reduction, the further inward the focal plane will be. That was fun. 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. 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. Most manufacturers provide this specification. Optically, it consists of a four-element lens that is fully multi-coated for high contrast and resolution. More about this below. Very helpful, thanks a lot for this article! If the focal reducer is to be used for visual observation, the visual back is threaded onto the eyepiece side of the reducer, and then a star diagonal and eyepiece are installed as usual. Style: Field stop diameters are one of the specified specs of eyepieces. For this test, I used a single configuration R/C, Click-lock, and 1.25 diagonal with the adapter. Better images are also obtained when using these focal reducers at a reduction factor of 0.5x 0.8x, approximately. The equations and argument in the Appendix of this article shows the relationship between the working distance and the reduction factor. 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. No difference. The internal surfaces are blackened and glare-threaded to provide the highest contrast. Check out our 2022 telescope buying guide here! Some refractors such the TeleVue Nagler-Petzval (NP), the Takahashi "FSQ", and the William Optics Redcat/WhiteCat 51 have inherently flat fields because of internal optical elements. But when not in the box or on the telescope, there is no cover for the other end. Request stock alerts and we'll let you know when the item is back in stock. The Buyer's Guide To Eyepieces at the top of the Eyepieces forum has a column for this spec. If you place your camera at a different working distance, you will get a different reduction factor and perhaps unwanted distortion in the image. 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. Will not focus with the stuff I have. More important, its clear that the Antares is a reducer/corrector, just like the Celestron and not merely a reducer. For me, I was looking for, and planning to keep, the one that yielded the greatest reduction. The nominal design reduction factor of these reducers is typically 0.5x. Celestron Solar Safe filter technology is GUARANTEED SAFE for direct solar observation and has been independently tested by SAI Global Assurance Services. Most Feather Touch focusers cost between $300-$350. And when used in some refractors, the field flattening is not as accurate as it is in the f/10 SCTs. What I do know is that the Antares and the Celestron samples that I have perform exactly the same from the center right out to the edges. 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. Both exhibited consistent reduction, identical field flattening, and edge correction properties, and both were high quality optically and mechanically. The stock Celestron visualback is just under 2 long. No negative issues to report. This means that there must be sufficient travel on the telescope focuser to make up for this. Increase that distance, and greater reduction results and visa versa. 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. Ive owned Celestron, Meade, and Antares models over the years at least a couple of each. We will be glad to help. Several functions may not work. Its a good thing I have the super lube handy or my neighbors wont be happy with me.come to think of it, Im sure the small mammals here wouldnt be thrilled either! Take control of your telescope! Many Ritchey-Chretien telescopes available today are made by GSO. Product Details. However, even though the imprint on the item states "Reducer / Corrector" please note that his is a reducer only. Thanks for pointing this out. Article Agena AstroProducts, 2019. For this shoot-out, I used a standard Celestron C8 with Starbright coatings. This focal reducer and field flattener consists of a four-element multicoated 40mm lens in a metal cell. If used before or beyond the working distance, unwanted image distortion may result. Stars had a tiny bit more sparkle and pop. For me the Antares was a little brighter and had the least scatter by a bit so the better coatings won. The lens has a knurled surface, providing a tremendous gripping surface for threading/unthreading. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. The C8 has no noticeable vignetting with a 32mm Plssl in the f/6.3 reducer. More aggressive reduction, or using these reducers with larger sensors, will result in aberrations and distortions near the edge of the image. 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. 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. Edited by bluewater, 05 September 2020 - 11:27 AM. if the illuminated field is 27mm wide without the reducer, it will be 27 x 0.63 = 17mm with it in place. Nebula Filters. 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. 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. Such an image circle is still large enough to encompass the relatively large sensor of many deep-sky astronomy cameras. That includes, for example, a 1.25" eyepiece with an apparent field of view of 68 and a focal length of 24mm (eg. Sign up for our newsletter to get exclusive deals, observing tips, and new product announcements. Optically, it consists of a four-element lens that is fully multi-coated for high contrast and resolution. 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. JavaScript seems to be disabled in your browser. 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. The resultant reduction factor was measured to be 0.46x. 160K views 9 years ago This video is a complete overview of focal reducers and how they function applying to telescopes. a Tele Vue Panoptic), or a Plossl eyepiece with an apparent field of view of 50 and a focal length of 32mm. Focal reducers for refractors are easy to use. Focus misses by about 1 turnof the focus knob.Here is my solution:Buy a shorter 1.25 visual back for my scope. 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. Opticstar F6.3 Focal Reducer / Corrector. He tested this on an 8 Celestron , I have a Celestron 6SE. Most different was that the sky background was a little darker and more uniform, providing a tiny contrast boost for fainter objects. 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. 1.2" in that scope is a field stop of 43mm at f/10 and 27mm at f/6.3. 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. Therefore, a 55mm back focus with a filter that is 3mm thick added to the imaging train would become 56mm. For example, a 0.8x reducer placed at the working distance provides a reduction of (1 0.8) x 100 = 20%. It is recommended for . Please let us know what topics you are interested in. Have always disliked the crude, noisy SCT threads, but I get it. The Reduction Factor and the Amount of Reduction are inversely related. Again, to my surprise, there was absolutely no difference between the Celestron and Antares on any star. I've heard and read all kinds of things about the Antares being only a reducer and not a corrector, etc. The focal length and design working distance for this focal reducer were not available from the manufacturer. I am new to these optic topics, and I want to ask you what happens with Masutov like SW or Celestron 4 or 7 inches. Easy solution found a very tiny dab of super lube on the threads and all was well and quiet. * Not a Retail Store * 16313 Arthur StreetCerritos, CA 90703, USA. Figure 2 shows the effective of a focal reducer on the light from a telescope objective. 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. Figure 1 shows the relationship between the focal reduction factor MR and the position of the reducer in the optical path. DUE TO EXTREMELY HIGH DEMAND, WE WILL NOT BE TAKING NEW ORDERS UNTIL MONDAY, DECEMBER 14. The designed reduction factor (0.5x in the case of the GSO reducer example above) should be considered a rule of thumb or approximate value in most cases, rather than a very precise number. I own both and concur heartily. Please re-enable javascript to access full functionality. Refractors, or SCTs with external focusers, may not have sufficient in-travel to reach focus in some configurations. As per the OP I still can't see any reason to buy the Celestron for significantly more $$$. Unleash the full pointing accuracy of your Celestron computerized telescope with a specialized telescope control software suite. Right off the bat, I was struck by how similar the two R/Cs were. For both imaging and visual observing, these reducers also improve image sharpness at the edge of the field by correcting for coma and field curvature. 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.