We have corrected # (iii) after equations 6 & 7. Since then, Agena has become one of the leading online retailers of telescopes and astronomical accessories worldwide. With spring galaxy season here, I decided to pick up a couple more to compare in a head-to-head shoot out. Images in the Celestron tended to appear ever-so-slightly dimmer (maybe? The resultant reduction factor was measured to be 0.46x. Once focused it's pretty good. If I had to guess, the difference is maybe 10-15 grams. 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. But the diameter of the image circle decreases by a factor of 0.63 to about 24mm. This means that there must be sufficient travel on the telescope focuser to make up for this. 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. F6.3 Focal reducer for F/10 or higher telescopes, 43mm aperture, 4-Element, Fully Multicoated. Optically, it consists of a four-element lens that is fully multi-coated for high contrast and resolution. Given the results of Test #1, I wanted to see if there was any truth to this assumption. - thanks. Hmmm . It's an either/or proposition: reducer and 1.25", or 2", but not 2" and reducer. Focal reducers for these relatively fast ED refractors are generally for imaging only, not for visual observation. I only have the Celestron f/6.3. They are also less expensive than many external focusers of similar build quality. While most Barlow lenses and focal extenders work with most kinds of telescopes available to amateur astronomers, focal reducers are designed to work in a narrow range of focal ratios of a telescope objective. Perfect for the serious student, professional scientist and discriminating hobbyist. 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). This focal reducer is made to attach to the rear cell of Schmidt-Cassegrain or Maksutov-Cassegrain telescopes. This also resulted in the clear aperture of the Antares being about 39-39.5mm, versus the Celestrons 41mm. I have/had both the Celestron (Japan) and Antares units. Celestron is considered better in terms of QA, less likely to come with free dust, hair or fingerprint. Thanks. Thanks Peter! Obviously bright objects like Jupiter or The Moon show the reflections. Please let us know what topics you are interested in. if the illuminated field is 27mm wide without the reducer, it will be 27 x 0.63 = 17mm with it in place. Yellow and orange members of open clusters stood out a bit more as the various stars displayed their individuality. Your price: $579.00. DUE TO EXTREMELY HIGH DEMAND, WE WILL NOT BE TAKING NEW ORDERS UNTIL MONDAY, DECEMBER 14. Each focal reducer has a fixed specification called the working distance or required back focus. If yes, what kind of focal reducers can I use? 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. Planetarium software package which provides easy-to-understand explanations and impressive visuals of all kinds. Benefits limited to hardware and conditions? 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. Reproduction without permission prohibited. Focal reducers are essential optical accessories for astrophotography, electronically-assisted astronomy (EAA), and in some cases, for visual observation with long focal ratio telescopes. 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. I had a Celestron, Antares and Hirsch for awhile and compared them over about a year. No results, please adjust your filters. I've only used it a few times but it looks good to me. They never really recovered from selling a few 15 years back with element reversed. Sign up to receive sale alerts, news about upcoming celestial events, and telescope tips from our experts! You cannot, for example, use a 0.63x focal reducer intended for a standard Celestron or Meade SCT and use it on a Celestron Edge HD or a Meade ACF. I've looked through one from Meade and first impression was that it was like the Celestron version. Turn it on and push Align. In about three minutes, youre ready to observe! Manish holds a Master's degree in Electrical Engineering from Virginia Tech and an MBA from the Kellogg School of Management at Northwestern University. In some cases, focal reducers also act as field flatteners by correcting for field curvature and coma of the objective lens. 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 use the Celestron version and it seems OK for both visual and imaging. Specially-designed focal reducers are available for use with these telescopes. In this configuration, the 29.5mm camera nosepiece and a 6mm extension ring positions the reducer at a working distance of 53.5mm from the camera sensor, which is located 12.5mm inside the front edge of the camera. So it provides a 0.63x design reduction factor when used with an f/10 SCT at the specified working distance. The reducer features fully coated optics in an anodized aluminum filter ring with an ergonomic rubber grip. 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. More aggressive reduction, or using these reducers with larger sensors, will result in aberrations and distortions near the edge of the image. As mentioned in Section 2 of this guide, the reduction factor of a focal reducer depends on its position in the optical path relative to the eyepiece or camera. 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. All Rights Reserved. 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. 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. They are reported as identical. I'm going with the Celestron. 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. The naming convention of SCT focal reducers is a little confusing. If I had to chose one, I would base my decision on your level of light pollution perhaps the Antares for its slightly higher transmission if you live under less light polluted skies, but the Celestron for its greater contrast if you are dealing with a suburban or urban light dome. Because I have not heard any complaints about the made in China R/C. 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. I doubt there is any difference between the Antares and the Celestron except price. 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. Is there likely to be any differences in performance between using these on an 8 or something smaller like my 6SE? In both cases will end with a similar tfov. Upon close inspection, it was clear that the housing of Antares assembled in Canada version was a little more substantial than the Celestron. 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. I've heard and read all kinds of things about the Antares being only a reducer and not a corrector, etc. No negative issues to report. Nowadays I tend to use the Celestron more with my refractors for imaging and viewing. A former wireless communications consulting engineer and management consultant to various Fortune 500 companies, Manish started Agena AstroProducts in 2003. I would not use the reducer with a 2" diagonal or eyepiece in the C6. 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. 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. 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. I focus using a moonlight electronic focuser and focusmax. 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. When using the diagonal, keep the field stops of the eyepieces under 20mm. I happily cycle through LRGB filters to build the image rather than do a whole run of one filter at a time. which looks like the same one. One focal reducer will not achieve optimum results with all types of telescopes, so there is no universal' focal reducer. Fortunately, my neighbors are not out in their backyards at 11 pm, or they may have thought I was torturing a small mammal. Depending on the design of the telescope, they may require separate focal reducers if they require focal reducers at all. 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. control and Sky Viewer display makes selecting your target easy. It was used strictly for imaging, not visual observing. Images made with my ZWO 533 camera testing both show them to be essentially the same. The more focal reduction, the further inward the focal plane will be. Some third-party vendors also make reducers for SCT scopes. CEL-94245. Learn more about extra solar planets imagery, 3D Star rendering, observation planning, telescope control, multiple-panel printing, and much more. . 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. Can these economical focal reducers from GSO and other vendors result in good images? It's usually specified in millimeters. Orders placed over the weekend will be shipped on the following Monday. The faster f/ratio allows you to use slower film or shoot in lower light level situations and still properly expose your subject. If you want to use them for visual - try maybe long focal length eyepieces rather than the reducer. Great report and verifies what I had thought all along, Fortunately, my neighbors are not out in their backyards at 11 pm, or they may have thought I was torturing a small mammal. 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. In every configuration, there were essentially parfocal, requiring only a tiny fine focus adjustment when changing correctors. The female end attaches to the rear cell of the telescope. Thanks guys, I'm trying to get my ZWO ASI120MC-S to work with my 90mm Meade. 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. CPWI has an extensive object database, employs PointXP mount modeling, and more. Many Ritchey-Chretien telescopes available today are made by GSO. Dedicated focal reducers for refractors are intended primarily for imaging, not visual observation. 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. Never noticed any anomalies with this unit. The female end attaches to the rear cell of the telescope. 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. . The problem with those SCT reducers is that they cause chromatic aberration and require refocusing when using parfocal RGB/other filters. 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. Stars had a tiny bit more sparkle and pop. 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. 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. 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. Reducer Lens .7x - EdgeHD 925 Learn More. I have a Raspberry HQ camera, a Sony TV Zoom 12.5-75mm f1.8 and a Astromania 1,25" 0.5x focal reducer. This is very impressive performance given how hard this problem is to mitigate in general. Style: CPWI has an extensive object database, employs PointXP mount modeling, and more. This focal reducer and field flattener consists of a four-element multicoated 40mm lens in a metal cell. Sign up for our newsletter to get exclusive deals, observing tips, and new product announcements. You may need spacers or a T-adapter to ensure the correcting working distance. October 11, 2010 in Discussions - Scopes / Whole setups. I have the Antares and have no complaints. Celestron Solar Safe filter technology is GUARANTEED SAFE for direct solar observation and has been independently tested by SAI Global Assurance Services. 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. This is a. If it's positioned further from the eyepiece or camera and closer to the telescope objective, the reduction factor increases. 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. Since the focal length of the reducer, FR, is fixed, as d2 increases then MR decreases. In some cases, focal reducers also act as field flatteners by correcting for field curvature and coma of the objective lens. More important, its clear that the Antares is a reducer/corrector, just like the Celestron and not merely a reducer. 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! 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. 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. A longer effective focal length leads to higher magnification with a given eyepiece for visual observers. Better images are also obtained when using these focal reducers at a reduction factor of 0.5x 0.8x, approximately. Possibly the design of the Antares was changed .. The equations in the Appendix show how this all works. 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. 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. 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 . But when not in the box or on the telescope, there is no cover for the other end. Add a 0.63x reducer, and the brightness of extended objects increases by (1/0.63)2 = 2.5. There are many different types of focal reducers and they all effect. 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. Most refractor manufacturers such as William Optics, Tele Vue Optics, Explore Scientific, Sky-Watcher, William Optics, and Stellarvue make their own focal reducers optimized for use with their telescopes. As a result, the smaller tube may cut into the light cone and effectively reduce the working aperture of the telescope. Torazz I wish there was. Copyright 2003-2022 Agena AstroProducts. Steve Refractors, or SCTs with external focusers, may not have sufficient in-travel to reach focus in some configurations. This would tell us exactly how well aberrations are corrected. The easiest way to use a focal reducer is to make sure you place it at the specified working distance in front of your camera or eyepiece.