These reducers can also be used for visual observing with SCT scopes with eyepieces with a field stop as large as 24-27mm. This "speeds up" the optical train by reducing the focal length and magnification of the scope, requiring less time to integrate the same signal. Due to the design, the Reducer/Corrector lens does diminish a small amount of field curvature common to all Schmidt Cassegrain telescopes but does not eliminate it. When you said, "in some cases" a focal reducer also works as a flattener/corrector, are you saying that not all focal reducers are flatteners/corrector? Well done. Orders placed after 12:00 PM Pacific Time will be shipped the next business day. InternetSales@optcorp.com, 800-483-6287 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. 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. They never really recovered from selling a few 15 years back with element reversed. Please let us know what topics you are interested in. 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. 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. Maybe I got a lemon. I would pay slightly more for the Japan produced version, just because Hirsch was not bad either but sold it since I had 2 already. I think I remember hearing the reduction factor is slightly different, cant remember more or less reduction. No experience with the Antares reducers, but I haven't personally seen a difference between Celestron and my current pair of made in Japan Meade reducers. looks virtually identical, except for the lettering. 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! 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. No small animals were harmed in making these observations. 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). A wider field of view and a lower magnification is also useful, with some focal reducers and with some eyepieces, for visual observers with telescopes with long focal ratios. Watch this before you buy Celestron 8SE SCT, or a Focal Reducer or a Celestron's EdgeHD reducers feature a custom 5 element optical design engineered to maintain the flat-field performance of our award-winning EdgeHD optical system. Have a promo code? We will be glad to help. It's an either/or proposition: reducer and 1.25", or 2", but not 2" and reducer. 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. If you want to use them for visual - try maybe long focal length eyepieces rather than the reducer. 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. The visual back must be removed first. Melotte 15 - First Process in PixInsight (easy! Newtonian reflectors will seldom be able to accommodate the in-focus travel demanded by focal reducers. I've looked through one from Meade and first impression was that it was like the Celestron version. By using this site, you agree to our Terms of Use. October 11, 2010 in Discussions - Scopes / Whole setups. Figure 1 shows the relationship between the focal reduction factor MR and the position of the reducer in the optical path. The reducer features fully coated optics in an anodized aluminum filter ring with an ergonomic rubber grip. For example, a 0.8x reducer placed at the working distance provides a reduction of (1 0.8) x 100 = 20%. In some cases, focal reducers also act as field flatteners by correcting for field curvature and coma of the objective lens. Does anyone have any experience with the Celestron and Antares focal reducers? In terms of reduction and correction which are what reducer/correctors are supposed to do both are superb. F6.3 Focal reducer for F/10 or higher telescopes, 43mm aperture, 4-Element, Fully Multicoated. So ab6110 is asking for a FR only without coma correction, there are a couple of brands who make special reducers for the ACF. 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. However, because the field curvatures in refractors and SCTs vary a lot, I would predict unpredictable effects inre: field curvature. Celestron Focus Motor for SCT, EdgeHD & 8" RASA, Celestron C6 0.63 reducer/flattener back focus. Focus misses by about 1 turnof the focus knob.Here is my solution:Buy a shorter 1.25 visual back for my scope. CPWI has an extensive object database, employs PointXP mount modeling, and more. This fully multi-coated lens provides maximum light transmission with near full-field illumination. Some are available in 1.25" barrel format but with C threads. Focal Reducer, 2", 0.7X. I have Hirsch focal reducer, which is yet another clone of the Celestron reducer. 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. 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 female end attaches to the rear cell of the telescope. Opticstar F6.3 Focal Reducer / Corrector. Back-Focus 101: DSLR Cameras & the Celestron f/6.3 Reducer - YouTube 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. With the Celestron Reducer/Corrector Lens, thats precisely what you get. Can you tell me about the use of reducers in Maksutov-Cassegrain telescopes? 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. The C8 has no noticeable vignetting with a 32mm Plssl in the f/6.3 reducer. 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. Who cares? Meade and Celestron both sell such SCT-T adapters with the correct optical length. 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. Again, these focal reducers are often provided by the telescope manufacturer. 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. On the trail, at the job site, in the classroom, or simply sitting at home relaxing the Celestron Elements ThermoTank 3 will keep your hands toasty. Sign up for OPT news, exclusive offers, and updates on the latest gear! It was also a little brighter in the center of the field with subtle darkening in the outer 20% or so. The nominal design reduction factor of these reducers is typically 0.5x. The Celestron f/6.3 is ~150 compared to the Antares at ~70. Please re-enable javascript to access full functionality. That includes, for example, a 1.25" eyepiece with an apparent field of view of 68 and a focal length of 24mm (eg. Completely stuck, completely frustrated. You can probably eke out 1.2 without noticing serious vignetting, which is a field stop of 31.5mm. I have a made in Japan 6.3 R/C and a made in China 6.3 R/C. This part is no longer in production, but it is sometimes available used and may be used with cameras with smaller sensors. I have the Antares and have no complaints. In the 1960s, Celestrons founder, Tom Johnson, created groundbreaking new telescopes never before seen on the consumer market. 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. Please note, orders placed after 10am on 2/28/2023 will be delayed. In terms of reduction and correction - which are what reducer/correctors are supposed to do - both are superb. Thanks for pointing this out. Telescope Optics, Rutten and van Venrooij, Chapter 15, Willman-Bell (1988). 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. If you place your camera at a different working distance, you will get a different reduction factor and perhaps unwanted distortion in the image. We have tested our current batch and it works with Meade, Celestron, and Baader SCT accessories. Increase that distance, and greater reduction results and visa versa. Once installed, you can add additional accessories like T-Adapters, 1.25 Visual Back, Star Diagonal, or Off-Axis Guider. Copyright 2003-2022 Agena AstroProducts. The lens is housed in machined aluminum for are machined aluminum black anodized. It works fine but you should stick with 1.25 EPs; or can use 2" EPs without corrector. Reviews. I wish there was. Theoretically each of these combinations all varied-length light paths should have resulted in slightly different reductions between the Celestron and Antares, since they supposedly have different focal lengths. Since the Celestron and Antares are supposed to have different focal lengths and spacing specs, I expected different results. Thanks Peter! Stars had a tiny bit more sparkle and pop. 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. A f/10 focal ratio now achieves a f/6.3, while an f/11 focal ratio now achieves a f/7. 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. 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. With spring galaxy season here, I decided to pick up a couple more to compare in a head-to-head shoot out. Request stock alerts and we'll let you know when the item is back in stock. Dedicated focal reducers for refractors are intended primarily for imaging, not visual observation. In such cases, we will be happy to take the item back as per our standard return terms. Does anyone know if the Antares 4000 focal reducer is as good as the Celestron focal reducer. Focal reducers also move the effective focal plane of the objective inward, that is, towards the objective (see Figure 1). Photographically you also get a wider field and much shorter exposures. Upgrading the Focuser of Your Schmidt-Cassegrain Telescope - Agena Astro Obviously bright objects like Jupiter or The Moon show the reflections. 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. 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. You attach the focal reducer to the rear port on a SCT and can keep it covered. The reducer fits all Meade and Celestron . In many cases, the answer is yes, especially for electronically-assisted astronomy (EAA). A focal reducer does just the opposite of a Barlow lens or focal extender. The internal surfaces are blackened and glare-threaded to provide the highest contrast. Check out our 2022 telescope buying guide here! Nowadays I tend to use the Celestron more with my refractors for imaging and viewing. Hello! Generally, views through the Antares seemed a little more transparent and brighter. 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. Once focused it's pretty good. Figure 6 shows a 1.25" focal reducer from GSO configured with a ZWO ASI224MC camera. Brian Ventrudo is a writer, scientist, and astronomy educator. 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. 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. Explore Scientific - Keys to the Universe Sale. My experience is that CN sellers are way above those listing elsewhere. 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. This also resulted in the clear aperture of the Antares being about 39-39.5mm, versus the Celestrons 41mm. Copyright 2021 Stargazers Lounge control and Sky Viewer display makes selecting your target easy. When using the diagonal, keep the field stops of the eyepieces under 20mm. A longer effective focal length leads to higher magnification with a given eyepiece for visual observers. 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. Free shipping $189.95 Contiguous US Customers:All items we sell ship for free within the Contiguous US. Reducer Lens .7x - EdgeHD 800 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). I happily cycle through LRGB filters to build the image rather than do a whole run of one filter at a time. 2023 Celestron, LLC. Download the Celestron PWI Telescope Control Software. 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. 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. 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. We have placed cookies on your device to help make this website better. 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. However, in principle, the reduction factor of a focal reducer can be varied by changing the distance from the back of the focal reducer to the camera or eyepiece. Very helpful, thanks a lot for this article! 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. The most commonly available focal reducers for SCTs are the f/6.3 reducers from Celestron and a similar f/6.3 focal reducer from Meade. They usually have a 2" barrel that slides into the telescope focuser. Focal reducers for SCT, RC, and field-flattened Edge HD or ACF telescopes thread onto the back of the telescope tube with 2"-24 or 3"-28 SCT threads. These RC reducers cannot be used with other types of telescopes. if the illuminated field is 27mm wide without the reducer, it will be 27 x 0.63 = 17mm with it in place. 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. Nada. Article Agena AstroProducts, 2019. If the reducer is placed elsewhere, at a position called the operating distance, the focal reduction factor will not be as advertised. They are also less expensive than many external focusers of similar build quality. The lens has a knurled surface, providing a tremendous gripping surface for threading/unthreading. As another example,GSO makes focal reducers for their line of Ritchey-Chretien imaging 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. Read our 101 article or get in touch. More about this below. How does it look thats what matters. But while the image gets brighter, the size of the image circle gets proportionately smaller. It seems right to put some distance between the camera and the focal reducer, right? 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. - thanks. 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. But the diameter of the image circle decreases by a factor of 0.63 to about 24mm. 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). USD $80.00. It's highly unlikely that they could be so precisely identical unless they were. The author finds differences in throughput and color balance, but then says he thinks the lenses are identical and he reaches his conclusions based on very long observing session. Thanks for the extremely valuable article. 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. The naming convention of SCT focal reducers is a little confusing. Reducer Lens .7x - EdgeHD 925 Ive owned Celestron, Meade, and Antares models over the years at least a couple of each. An eyepiece with a 27mm field stop yields a true field of 1.03 in the C6 at f/10. Does anyone know if the Antares 4000 focal reducer is as good as the Celestron focal reducer. This focal reducer and field flattener consists of a four-element multicoated 40mm lens in a metal cell. 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. More details are found in the Appendix of this article. However, even though the imprint on the item states "Reducer / Corrector" please note that his is a reducer only. Manish holds a Master's degree in Electrical Engineering from Virginia Tech and an MBA from the Kellogg School of Management at Northwestern University. It's usually specified in millimeters. I don't know. For imagers, the main purpose of a focal reducer is to increase the brightness of the image at the focal plane. 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 threads were similar on the eyepiece end, but a bit smoother. If used with other f/ratios, the field flattening characteristic may be unpredictable. Style: No results, please adjust your filters. 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. CPWI has an extensive object database, employs PointXP mount modeling, and more. 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. Celestrons FREE planetarium app is an astronomy suite that redefines how you experience the night sky. Since 2008, Brian has taught astronomy to tens of thousands of stargazers through his websites OneMinuteAstronomer.com and CosmicPursuits.com. 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. 3. Best evidence would by obtained by using a camera and evaluating the image both by eye and with a computer analysis. (Note: Using the simple equations above, the focal length of this reducer can be estimated to be about 350mm). Antares f/6.3 SCT Focal Reducer - Rother Valley Optics Ltd . All rights reserved. The faster f/ratio allows you to use slower film or shoot in lower light level situations and still properly expose your subject. Focal reducers for these relatively fast ED refractors are generally for imaging only, not for visual observation. I really don't see any difference in the current crop except the "Meade" is usually the cheapest. If used before or beyond the working distance, unwanted image distortion may result. Thks for that and its not for visual it for astrophotography. We do not price match competitors if they are out of stock. An f/6.3 reducer is designed to reduce the focal ratio of an f/10 SCT to f/6.3. For the best experience on our site, be sure to turn on Javascript in your browser. 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. During check-out, you will be presented with several shipping choices and costs. This innovative software solves the time-consuming problem of trying to pinpoint the North Celestial Pole. 1.2" in that scope is a field stop of 43mm at f/10 and 27mm at f/6.3. Focal reducers are essential optical accessories for astrophotography, electronically-assisted astronomy (EAA), and in some cases, for visual observation with long focal ratio telescopes. I have a Raspberry HQ camera, a Sony TV Zoom 12.5-75mm f1.8 and a Astromania 1,25" 0.5x focal reducer. The most popular accessories for your new telescope! Unscrew that wide angle lens and put it away, then attach the ASI120 to the nose-piece that came with the camera and fit that into the eyepiece holder. Will not focus with the stuff I have. SKU: CEL-94245. 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. I found both to be very good. 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 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. But is there a difference in quality between the Antares and the Celestron or Meade focal reducers? 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). Celestron or Antares? Optically, it consists of a four-element lens that is fully multi-coated for high contrast and resolution. Performance wise what differences might there be using the reducer on a smaller scope. Rather than a direct side-by-side, I swapped the reducers so that I was using them on the exact same, well-collimated instrument.
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