Besides observing from his heavily light polluted backyard in Los Angeles, Manish enjoys conducting astronomy outreach programs in local schools. 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's partly because focal reducers correct for field curvature, which itself depends on the focal ratio and other optical design factors of the telescope. Images in the Celestron tended to appear ever-so-slightly dimmer (maybe? The C8 has no noticeable vignetting with a 32mm Plssl in the f/6.3 reducer. A useful thing to know is how far from the objective lens (for a refractor) is the focal reducer located. Copyright 2003-2022 Agena AstroProducts. We will match any online price that we confirm as valid. For visual use, this means you get lower power with the same eyepiece and a wider field of view. 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. Quite interestingly it bears the very same engravings of the Meade 4000 r/c (including "series 4000") except for "MEADE". Getting the proper back-focus for your imaging camera is a vital step in getting the best data possible out of your telescope imaging/research rig. In most cases, the easiest option is to choose the focal reducer made specifically for your telescope. So Celestron buyers like Celestron, Meade buyers like the Meade and Antares buyer like the Antares. As a result, the smaller tube may cut into the light cone and effectively reduce the working aperture of the telescope. Sign up for our newsletter to get exclusive deals, observing tips, and new product announcements. This focal reducer is made to attach to the rear cell of Schmidt-Cassegrain or Maksutov-Cassegrain telescopes. This factor is designated by a power that is less than 1, and it usually lies between 0.5x or 0.8x. I have the Antares and have no complaints. 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. He also holds a Ph.D. in engineering physics from McMaster University. For example, a 0.8x reducer placed at the working distance provides a reduction of (1 0.8) x 100 = 20%. Description. Looking forward to the day when I can do a shoot-out between a Japan and China Celestron, just for kicks. If the reducer is placed elsewhere, at a position called the operating distance, the focal reduction factor will not be as advertised. 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. 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. 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. Please note, orders placed after 10am on 2/28/2023 will be delayed. Celestron or Antares? Reducer - Corrector Your wishlist has been temporarily saved. Here, there was a subtle difference . 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. 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. I only have the Celestron f/6.3. I have a Raspberry HQ camera, a Sony TV Zoom 12.5-75mm f1.8 and a Astromania 1,25" 0.5x focal reducer. Does anyone know if the Antares 4000 focal reducer is as good as the Celestron focal reducer. We will be glad to help. Maybe I got a lemon. 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. 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. 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. DUE TO EXTREMELY HIGH DEMAND, WE WILL NOT BE TAKING NEW ORDERS UNTIL MONDAY, DECEMBER 14. 2. Manish Panjwani has been an active amateur astronomer since before Halley's Comet last flew by our neighborhood. Add a 0.63x reducer, and the brightness of extended objects increases by (1/0.63)2 = 2.5. You may need spacers or a T-adapter to ensure the correcting working distance. I found both to be very good. Reducer Lens .7x - EdgeHD 925 Learn More. Bear in mind you can't squeeze blood out of a turnip, i.e. ED glass is specially formulated and contains rare-earth compounds that greatly reduce a visual defect called chromatic aberration. Figure 1 shows the relationship between the focal reduction factor MR and the position of the reducer in the optical path. Thanks for any advice or experience you could share. An eyepiece with a 27mm field stop yields a true field of 1.03 in the C6 at f/10. More important, its clear that the Antares is a reducer/corrector, just like the Celestron and not merely a reducer. 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. The working distance or required back focus, explained above, is usually specified and is far more important in practice. Start Chat I've heard and read all kinds of things about the Antares being only a reducer and not a corrector, etc. 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. An image of about 24mm across, approximately, allows an observer to use a 1.25" eyepiece with a maximal field stop. In terms of reduction and correction - which are what reducer/correctors are supposed to do - both are superb. Each focal reducer has a fixed specification called the working distance or required back focus. But the diameter of the image circle decreases by a factor of 0.63 to about 24mm. Our patented SkyAlign alignment technology makes setting up a computerized telescope simple, fast, and accurate. 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. With the barrel 1.25 reducer won't focus, all I get is fuzzy snowballs. Sharpness is essentially the same. Hello! I had a Celestron, Antares and Hirsch for awhile and compared them over about a year. 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. This also resulted in the clear aperture of the Antares being about 39-39.5mm, versus the Celestrons 41mm. . 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 or Antares f/6.3 focal reducer for SCT? Can these economical focal reducers from GSO and other vendors result in good images? Sign up to receive sale alerts, news about upcoming celestial events, and telescope tips from our experts! 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. 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. The resultant reduction factor was measured to be 0.46x. The lens has a knurled surface, providing a tremendous gripping surface for threading/unthreading. ), but stars seemed a bit tighter and their colors were richer and more dramatic. 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. For example, many focal reducers designed for f/7 or f/8 ED refractors such as those from Tele Vue, William Optics, Sky-Watcher, and Meade are designed to have a working distance (or back focus) of 55mm. The lens that the ZWO comes with give a perfect wide angle image of what is in front of it. I wonder whether, for example, Antares focal reducer for SCT belongs to the latter category. Stars in the corner of the image frame are indistinguishable between the Antares and the Celestron. 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. In terms of reduction and correction which are what reducer/correctors are supposed to do both are superb. Given past experience with them, I decided not to include the Meade version in my little experiment, as I have never met one I liked from getting one of the too-short focal length models, to one with some overflow cement in the doublet, to focus difficulties with some eyepieces. Nowadays I tend to use the Celestron more with my refractors for imaging and viewing. Not one detectable iota of discernable difference. Focal reducers for refractors are easy to use. Brian Ventrudo is a writer, scientist, and astronomy educator. But while the image gets brighter, the size of the image circle gets proportionately smaller. 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. 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. With both, using the same diagonal set-up, the exact same stars were visible at the very edge of the FOV. Also, the focusers of most Newtonians do not have enough in-travel to accommodate a focal reducer. I have both the Antares and the Celestron reducers. We have placed cookies on your device to help make this website better. 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. For the best experience on our site, be sure to turn on Javascript in your browser. I use it on my C8 SCT with a 1000d, and it seems to do everything written on the tin. * Not a Retail Store * 16313 Arthur StreetCerritos, CA 90703, USA. Focal reducers for refractors with focal ratio of f/7 to f/9, roughly, have a design reduction factor of about 0.75x to 0.8x and produce a flat field by correcting for the curvature of the objective lens. And, the reality is that every F/6.3 RC out there Celestron, Hirsch, Astromania, etc., etc. All rights reserved. The Antares is supposed to be pretty comparable. I have Hirsch focal reducer, which is yet another clone of the Celestron reducer. The more focal reduction, the further inward the focal plane will be. They only publish the value of D, the working distance (sometimes called the back focus distance) and the design reduction factor MRD. If you want to save a few buck watch the classifieds on CN. 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. The amount of reduction is simply the percentage by which a reducer shortens the effective focal length of a telescope and is calculated as (1 Reduction Factor) x 100%. The reducer fits all Meade and Celestron . 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. Easy solution found a very tiny dab of super lube on the threads and all was well and quiet.. because they really dont matter. . 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. Focal reducers are essential optical accessories for astrophotography, electronically-assisted astronomy (EAA), and in some cases, for visual observation with long focal ratio telescopes. Benefits limited to hardware and conditions? 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. Field stop diameters are one of the specified specs of eyepieces. Thanks guys, appreciate the feedback. . 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. Enter it during checkout! Never used one, but read the reviews here that suggest a coating problem. We have corrected # (iii) after equations 6 & 7. Celestrons aplanatic EdgeHD optics revolutionized astroimaging. Not a bit. Equation (4) shows the relationship between the distance d2 and the reduction factor MR. Dedicated focal reducers for refractors are intended primarily for imaging, not visual observation. riklaunim Members 559 3,445 Location: Poland Posted October 11, 2010 They are reported as identical. Yellow and orange members of open clusters stood out a bit more as the various stars displayed their individuality. Refractors, or SCTs with external focusers, may not have sufficient in-travel to reach focus in some configurations. The naming convention of SCT focal reducers is a little confusing. These reducers can also be used for visual observing with SCT scopes with eyepieces with a field stop as large as 24-27mm. Thank you so much for the informative article, I now understand better how to integrate my reducer into my system to get better performance. Thanks Peter! Details: The item must be the identical item, brand name, size, weight, color, quantity and model number. Unlike . 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. Still not sure what is the right gear for you? Get ready for a night of astroimaging with your mount faster than previously thought possible with All-Star Polar Alignment. One problem with getting opinions is that most of use do not have both reducers or have never done a side by side comparison. The most significant mechanical variation, however, is the quality and precision of the threading. In some cases, focal reducers also act as field flatteners by correcting for field curvature and coma of the objective lens. This standard distance is a consequence of the design of DSLR cameras for which the distance of the sensor to the outer edge of the flanges is about 45 mm, while the T-ring that attaches to the flange for astrophotography is about 10mm thick. 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.