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. High power views will provide flatter fields all the way to the edge, both visually and photographically. The naming convention of SCT focal reducers is a little confusing. Some are available in 1.25" barrel format but with C threads. An image of about 24mm across, approximately, allows an observer to use a 1.25" eyepiece with a maximal field stop. This would tell us exactly how well aberrations are corrected. 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. 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. Sign up for a new account in our community. The Buyer's Guide To Eyepieces at the top of the Eyepieces forum has a column for this spec. Celestron is considered better in terms of QA, less likely to come with free dust, hair or fingerprint. 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 . The female end attaches to the rear cell of the telescope. Whereas the Celestron threaded smoothly onto the scope, the Antares chattered and squeaked a bit more so when being removed. In both cases will end with a similar tfov. These RC reducers cannot be used with other types of telescopes. 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. The nominal design reduction factor of these reducers is typically 0.5x. Our proprietary StarBright XLT optical coatings dramatically increase transmission, up to 97.4% on our Schmidt corrector lenses. Not noticed any optical problems. 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. 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's an either/or proposition: reducer and 1.25", or 2", but not 2" and reducer. But in the Japan version I have never noticed any anomaly like the ghosting in the China R/C. 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. Here, there was a subtle difference . 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). Some third-party vendors also make reducers for SCT scopes. Does anyone know if the Antares 4000 focal reducer is as good as the Celestron focal reducer. and you will be fine. For the best experience on our site, be sure to turn on Javascript in your browser. Fortunately, my neighbors are not out in their backyards at 11 pm, or they may have thought I was torturing a small mammal. In such cases, we will be happy to take the item back as per our standard return terms. 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. 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). The visual back must be removed first. 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. More details are found in the Appendix of this article. 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. You can probably eke out 1.2 without noticing serious vignetting, which is a field stop of 31.5mm. Best evidence would by obtained by using a camera and evaluating the image both by eye and with a computer analysis. Some coma is visible in the corners, but the image is quite good for EAA applications. 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. 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. The lens has a knurled surface, providing a tremendous gripping surface for threading/unthreading. A focal reducer does just the opposite of a Barlow lens or focal extender. This fully multi-coated lens provides maximum light transmission with near full-field illumination. The review is a subjective visual impression, which is interesting but not best evidence. 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. It is recommended for . Equation (4) shows the relationship between the distance d2 and the reduction factor MR. I only have the Celestron f/6.3. We reserve the right to verify a competitor's advertised price and the availability of the item. In most cases, the easiest option is to choose the focal reducer made specifically for your telescope. Have always disliked the crude, noisy SCT threads, but I get it. USD $80.00. Well done. It must be in stock at the time of Price Match for us to make a guarantee. 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. It is not a corrector or flattener. I've heard and read all kinds of things about the Antares being only a reducer and not a corrector, etc. By using this site, you agree to our Terms of Use. CPWI has an extensive object database, employs PointXP mount modeling, and more. 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. Most manufacturers provide this specification. Today, our world-class team of optical and electronic engineers continues to push the boundaries of technology. 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. From the SkyProdigy, a telescope so smart it can align itself, to our high-performance EdgeHD optical system, weve revolutionized the hobby of astronomy for beginners and advanced amateurs alike. I wont bother with differences in packaging, caps, etc. Some manufacturers will specify the working distance from the middle of the rear lens surface, and this number must then be converted into a practical working distance number by subtracting the amount by which the rear lens surface is recessed in its housing. If I had to go out on a very thick limb, I would have to say that these two reducers/correctors are, indeed, identical the exact same glass in slightly different housings with different lettering. . control and Sky Viewer display makes selecting your target easy. More important, its clear that the Antares is a reducer/corrector, just like the Celestron and not merely a reducer. Upon close inspection, it was clear that the housing of Antares assembled in Canada version was a little more substantial than the Celestron. Celestrons award-winning Nature DX binocular gets a major upgrade with the addition of ED objective lenses. Thanks for pointing this out. 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. if the illuminated field is 27mm wide without the reducer, it will be 27 x 0.63 = 17mm with it in place. The Antares focal reducer comes in small box. This article explains the basics of how focal reducers work with an astronomy telescope. Easy solution found a very tiny dab of super lube on the threads and all was well and quiet. As one increases, the other decreases. 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). More about this below. It also leads to larger (although fainter) images of extended objects like the Moon or planets for astrophotographers or visual observers. With the barrel 1.25 reducer won't focus, all I get is fuzzy snowballs. 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. Please let us know what topics you are interested in. 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. 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. It's highly unlikely that they could be so precisely identical unless they were. The camera side of the focal reducer is threaded for a T-adapter with wide M48 threads, or in some cases, with smaller M42 threads. But the smaller image circle means there is a limit to the field stop of an eyepiece that can achieve an unvignetted image. 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. Obviously bright objects like Jupiter or The Moon show the reflections. No rainchecks will be issued for items out of stock at OPTcorp.com to match a competitor's price. ED stands for "extra-low dispersion," which refers to the composition and optical properties of the glass used for the lenses. Style: Optically, it consists of a four-element lens that is fully multi-coated for high contrast and resolution. Focus misses by about 1 turnof the focus knob.Here is my solution:Buy a shorter 1.25 visual back for my scope. However, manufacturers virtually never provide this specification. I wish there was. All Rights Reserved. Reducer Lens .7x - EdgeHD 925 How about for visual observers? Focal reducers for many SCTs and their flat-field equivalents usually have a back-focus distance of 105mm. Specially-designed focal reducers are available for use with these telescopes. I had a Celestron, Antares and Hirsch for awhile and compared them over about a year. External Focusers for Schmidt-Cassegrain Telescopes 3.1 The Basics of SCT Threads In some cases, focal reducers also act as field flatteners by correcting for field curvature and coma of the objective lens. 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. As a Barlow's magnification increases with increasing distance from the Barlow, a focal reducer's reduction increases with increasing distance from the reducer. These 0.63x focal reducers were originally designed to optimize for an image circle to match 36mm x 24mm film or its digital equivalent for astrophotography. Turn it on and push Align. In about three minutes, youre ready to observe! 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. 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. Reducer Lens .7x - EdgeHD 1400 Learn More. That is definitely a 2" eyepiece, but it is not a large or long focal length 2" eyepiece. . Meade once made an f/3.3 focal reducer for SCT scopes. Go behind the scenes with Celestrons product development team and learn more about our award-winning and patented innovations. Will not focus with the stuff I have. However, some focal reducers can be used on other models of telescopes, but this is not always possible. Reducer Lens .7x - EdgeHD 800 However, some focal reducers can be used over a wider range of working distances, especially those with simpler optical design, and especially when used with cameras with smaller sensors. 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. Stars had a tiny bit more sparkle and pop. I really don't see any difference in the current crop except the "Meade" is usually the cheapest. This focal reducer from Celestron reduces the effective focal length by 0.63X Enjoy the wider field of view & faster exposure times at f/6.3 with f/10 telescopes f/11 telescopes, such as the C14 will perform at f/7 The Celestron f/6.3 Reducer has four fully-multicoated elements Reduce your exposure times by a factor of 3! 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. Again, to my surprise, there was absolutely no difference between the Celestron and Antares on any star. Field stop diameters are one of the specified specs of eyepieces. For imagers using longer focal-length refractors and SCTs, especially when using smaller sensors that place less demand on the focal reducer, there are economical alternatives for focal reducers from manufacturers such as GSO, Agena, and Antares. The Reducer/Corrector can also be used for terrestrial digiscoping. A couple of tiny dust particles between lens elements, uneven lens edge blackening, very minor coating blemishes, or even a very small fine lens scratch or two are very common in this Antares product and must be accepted as normal for this item. Oceanside Photo & Telescope wants our customers to shop with confidence knowing that you will always get the best deal available. Article Agena AstroProducts, 2019. Celestron or Antares f/6.3 focal reducer for SCT? 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. riklaunim Members 559 3,445 Location: Poland Posted October 11, 2010 They are reported as identical. We process your personal data as stated in our. The f/6.3 reducer is operating at f/5-f/5.5 with a 2" diagonal, depending on the back focus length of the diagonal. I use the Celestron version and it seems OK for both visual and imaging. I read another thread in a different forum about F6.3 reducer correctors and one amateur posted an image about glue coming out of an astromania f6.3 reducer which he planned to return. Performance wise what differences might there be using the reducer on a smaller scope. Refractors, or SCTs with external focusers, may not have sufficient in-travel to reach focus in some configurations. 2023 Celestron, LLC. Celestrons FREE planetarium app is an astronomy suite that redefines how you experience the night sky. My application is mostly visual now, but I'm looking to do more astrophotography over time. For example, an 8" SCT without a focal reducer has an illuminated field of 38mm at 50% fall-off. I focus using a moonlight electronic focuser and focusmax. 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%. Manish holds a Master's degree in Electrical Engineering from Virginia Tech and an MBA from the Kellogg School of Management at Northwestern University. Another factor to consider: focal reducers also increase the angle at which light approaches the focal plane. So it provides a 0.63x design reduction factor when used with an f/10 SCT at the specified working distance. Read our guide! No idea what the issue is. The distances d1 andd2 can also be expressed in terms of the focal length of the focal reducer FR with the lens equation: Using Equation 2, Equation 1 can also be expressed in terms of d2: The focal reduction factor of the focal reducer depends on its focal length and its distance from the focal plane of the objective as shown by Equation 4: Again, for example, when the focal reducer is placed at the original focal plane of the objective, d1=0 and MR=1, which means there is no focal reduction. It has only one cover, which surprised me. In many cases, the answer is yes, especially for electronically-assisted astronomy (EAA). 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. 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. No retailers currently carry this product. Thanks guys, appreciate the feedback. 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. They are designed (assuming you are referring to the f/6.3 version) for the f/10 light cone. He tested this on an 8 Celestron , I have a Celestron 6SE. I would not use the reducer with a 2" diagonal or eyepiece in the C6. Figure 2 shows the effective of a focal reducer on the light from a telescope objective. The focal length of a focal reducer is usually measured from the rear lens surface of the reducer (and not the reducer's housing). No difference. Watch this before you buy Celestron 8SE SCT, or a Focal Reducer or a Hyperstar 7,758 views Mar 28, 2018 145 Dislike Share Ray's Astrophotography 42.3K subscribers Note: I am not paid or. This is very impressive performance given how hard this problem is to mitigate in general. 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. We will be glad to help. With spring galaxy season here, I decided to pick up a couple more to compare in a head-to-head shoot out. Unlike . Since the Celestron and Antares are supposed to have different focal lengths and spacing specs, I expected different results. I happily cycle through LRGB filters to build the image rather than do a whole run of one filter at a time. I have/had both the Celestron (Japan) and Antares units. Generally, views through the Antares seemed a little more transparent and brighter. It's usually specified in millimeters. This innovative software solves the time-consuming problem of trying to pinpoint the North Celestial Pole. (Note: Using the simple equations above, the focal length of this reducer can be estimated to be about 350mm). Celestrons aplanatic EdgeHD optics revolutionized astroimaging. With the Celestron Reducer/Corrector Lens, thats precisely what you get. As another example,GSO makes focal reducers for their line of Ritchey-Chretien imaging telescopes. There may have been an almost imperceptible difference, but the Antares and Celestron were producing precisely the same reduction. Reducer Lens .7x - EdgeHD 800 Learn More. Have a promo code? 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. Ive owned Celestron, Meade, and Antares models over the years at least a couple of each. During a twenty-year scientific career, he developed laser systems to detect molecules found in interstellar space and planetary atmospheres, and leveraged his expertise to create laser technology for optical communications networks. However, doesn't fit in the telescope and even if it did wouldn't work. The previous post shows the reducer on what appear to be two different refractors. 160K views 9 years ago This video is a complete overview of focal reducers and how they function applying to telescopes. My Celestron was made in China and the Antares in Canada. Because most modern Newtonians already have relatively fast focal ratios, these telescopes do not usually use focal reducers. If it's positioned further from the eyepiece or camera and closer to the telescope objective, the reduction factor increases. * Not a Retail Store * 16313 Arthur StreetCerritos, CA 90703, USA. For this shoot-out, I used a standard Celestron C8 with Starbright coatings. 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). You may need spacers or a T-adapter to ensure the correcting working distance. 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. 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. Many focal reducers are meant to be used within a few millimeters of the specified working distance to achieve the best possible image results. Optically, it consists of a four-element lens that is fully multi-coated for high contrast and resolution. 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. You also wont be unhappy spending the few extra bucks on the Celestron for the pretty orange lettering, particularly if you can pick one up used, as I did. They are commonly available in 1.25" and 2" threaded cells that conveniently thread into the nosepiece of a compatible camera or the barrel of an eyepiece. Not one detectable iota of discernable difference. I also used several eyepieces including the ES 24mm/68, 17.5mm and 12.5mm Morpheuses, and a 10.5mm Pentax XL. Your mileage may vary. We have placed cookies on your device to help make this website better. Unleash the full pointing accuracy of your Celestron computerized telescope with a specialized telescope control software suite. Also read the reviews here, including those at 4 stars. 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. Observing the microscopic world has never been easier! These reducers can also be used for visual observing with SCT scopes with eyepieces with a field stop as large as 24-27mm. In your opinion, is the Celestron is worth the added cost ($150 vs. $90)? However, the China 6.3 R/C has noticeable internal reflections that I haven't figured out yet. 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. 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. Antares or Celestron? 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.
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