Assuming you use the reducer with the stock 1.25" diagonal, it will operate at f/6.3. As a consequence, the standard f/6.3 and f/3.3 focal reducers for SCT scopes do not work. It's an either/or proposition: reducer and 1.25", or 2", but not 2" and reducer. Please note, orders placed after 10am on 2/28/2023 will be delayed. Please let us know what topics you are interested in. 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). You attach the focal reducer to the rear port on a SCT and can keep it covered. Yet, the Antares still easily and fully threaded without any hitches. 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. 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. The Antares is supposed to be pretty comparable. It is not a corrector or flattener. A slight nod to the Antares for heft and higher transmission, but points to the Celestron for nice threads and better contrast. Most different was that the sky background was a little darker and more uniform, providing a tiny contrast boost for fainter objects. This appendix summarizes how this works based on simple equations from the book Telescope Optics by Rutten and van Venrooij. 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. Your eyepieces are the first accessories you should learn to use with your telescope. Contiguous US Customers:All items we sell ship for free within the Contiguous US. control and Sky Viewer display makes selecting your target easy. 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. https://www.celestron.com/products/reducer-corrector, //cdn.shopify.com/s/files/1/1935/4371/products/94175_reducer_corrector_01.jpg?v=1603736883, //cdn.shopify.com/s/files/1/1935/4371/products/94175_reducer_corrector_01_medium.jpg?v=1603736883, Popular Science by Celestron StarSense Explorer DX 5" Smartphone App-Enabled Schmidt Cassegrain Telescope, Advanced VX 8" Schmidt-Cassegrain Telescope, C9.25 Optical Tube Assembly (CGE Dovetail), Advanced VX 6" Schmidt-Cassegrain Telescope, Advanced VX 700 Maksutov Cassegrain Telescope, CGX-L Equatorial 925 Schmidt-Cassegrain Telescope, CPC 1100 GPS (XLT) Computerized Telescope, CGX-L Equatorial 1400 Schmidt-Cassegrain Telescope, CGX-L Equatorial 1100 Schmidt-Cassegrain Telescope, CGX Equatorial 925 Schmidt-Cassegrain Telescope, CGX Equatorial 800 Schmidt-Cassegrain Telescope, CGX Equatorial 1100 Schmidt-Cassegrain Telescope, CGEM II 1100 Schmidt-Cassegrain Telescope, Advanced VX 9.25" Schmidt-Cassegrain Telescope, Advanced VX 11" Schmidt-Cassegrain Telescope, Not compatible with #93648 Off-Axis Guider, not compatible with #93519 2" Mirror Diagonal (discontinued), Currently not compatible due to mechanical interferences. 3. 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. M44 was a perfect target for this, as its large size maxes out the FOV on a C8 with a corrector, and its bright stars make great targets for measuring the very edge of the visible field. 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. Your price: $579.00. We will match any online price that we confirm as valid. Very helpful, thanks a lot for this article! 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. Reducer Lens .7x - EdgeHD 1400 Learn More. I have/had both the Celestron (Japan) and Antares units. For the best experience on our site, be sure to turn on Javascript in your browser. Orders placed after 12:00 PM Pacific Time will be shipped the next business day. This means that there must be sufficient travel on the telescope focuser to make up for this. Unlike . 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 results, please adjust your filters. 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. Possibly the design of the Antares was changed .. Nowadays I tend to use the Celestron more with my refractors for imaging and viewing. Reducer - Corrector Learn More. However, the China 6.3 R/C has noticeable internal reflections that I haven't figured out yet. 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. It was also a little brighter in the center of the field with subtle darkening in the outer 20% or so. 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. Now It only focuses near things, like some kind of macro zoom. With spring galaxy season here, I decided to pick up a couple more to compare in a head-to-head shoot out. 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. If you want to save a few buck watch the classifieds on CN. 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. I use the same back spacing for both on a small 6" Celestron SCT. Reducer - Corrector I use it on my C8 SCT with a 1000d, and it seems to do everything written on the tin. Because I have not heard any complaints about the made in China R/C. I also used several eyepieces including the ES 24mm/68, 17.5mm and 12.5mm Morpheuses, and a 10.5mm Pentax XL. 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. Refractors, or SCTs with external focusers, may not have sufficient in-travel to reach focus in some configurations. A few people have reported issues with the male SCT thread diameter on this item being a bit larger than necessary. This fully multi-coated lens provides maximum light transmission with near full-field illumination. Focus misses by about 1 turnof the focus knob.Here is my solution:Buy a shorter 1.25 visual back for my scope. 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. Celestrons aplanatic EdgeHD optics revolutionized astroimaging. 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. * Not a Retail Store * 16313 Arthur StreetCerritos, CA 90703, USA, Availability: Item has been discontinued by Agena and we no longer carry this item. DUE TO EXTREMELY HIGH DEMAND, WE WILL NOT BE TAKING NEW ORDERS UNTIL MONDAY, DECEMBER 14. These RC reducers cannot be used with other types of telescopes. The most significant mechanical variation, however, is the quality and precision of the threading. Easy solution found a very tiny dab of super lube on the threads and all was well and quiet. All rights reserved. No idea what the issue is. 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. 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. Copyright 2003-2022 Agena AstroProducts. 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. Thanks. Images in the Celestron tended to appear ever-so-slightly dimmer (maybe? 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. Using this same example of an 8" SCT and a 0.63x reducer, a visual observer can also enjoy brighter images and a wider field of view. 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. Download the Celestron PWI Telescope Control Software. 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. But the smaller image circle means there is a limit to the field stop of an eyepiece that can achieve an unvignetted image. 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. 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. For visual use, this means you get lower power with the same eyepiece and a wider field of view. 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. Meade and Celestron both sell such SCT-T adapters with the correct optical length. Will not focus with the stuff I have. Sign up for our newsletter to get exclusive deals, observing tips, and new product announcements. 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. 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. No small animals were harmed in making these observations. Ive owned Celestron, Meade, and Antares models over the years at least a couple of each. Both exhibited consistent reduction, identical field flattening, and edge correction properties, and both were high quality optically and mechanically. To calculate how much back focus spacing you need to add, take the thickness of the filter and divide it by 3. Here, there was a subtle difference . What an enjoyable read and detailed comparison. 3. Best evidence would by obtained by using a camera and evaluating the image both by eye and with a computer analysis. Another factor to consider: focal reducers also increase the angle at which light approaches the focal plane. which looks like the same one. Michael 1 ronin Members That includes, for example, a 1.25" eyepiece with an apparent field of view of 68 and a focal length of 24mm (eg. There may have been an almost imperceptible difference, but the Antares and Celestron were producing precisely the same reduction. In your opinion, is the Celestron is worth the added cost ($150 vs. $90)? We have corrected # (iii) after equations 6 & 7. CPWI has an extensive object database, employs PointXP mount modeling, and more. 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. Stars in the corner of the image frame are indistinguishable between the Antares and the Celestron. Celestron or Antares f/6.3 focal reducer for SCT? I have an 8SE, and am thinking about getting a focal reducer. As often noted in reviews and forum threads, Antares products tend to have threads that are a little less precise, and this specimen certainly demonstrated this. 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. Many focal reducers for refractors have a working distance (or back focus distance) of 55mm. I think that the FRs made in Japan in the day may have been better. One focal reducer will not achieve optimum results with all types of telescopes, so there is no universal' focal reducer. Celestron Focus Motor for SCT, EdgeHD & 8" RASA, Celestron C6 0.63 reducer/flattener back focus. Start here to find the perfect telescope for you! Please Log in to save it permanently. However, I noticed immediately that the Antares had a bit more of an heft to it, giving it a solid feel the Celestron didnt possess. Antares or Celestron? CPWI has an extensive object database, employs PointXP mount modeling, and more. Planetarium software package which provides easy-to-understand explanations and impressive visuals of all kinds. Not one detectable iota of discernable difference. This would tell us exactly how well aberrations are corrected. 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. 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. 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 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 more focal reduction, the further inward the focal plane will be. 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. 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. Start Chat One of the most important factors in a telescope is its transmissionthe percentage of light that reaches the focal plane. The new Lithium Phosphate (LiFePO4) battery chemistry has significant advantages over other battery chemistries, great for for those Astronomers on the go. Check out our 2022 telescope buying guide here! These scopes are compatibles with focal reducers. The Reduction Factor and the Amount of Reduction are inversely related. 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. My application is mostly visual now, but I'm looking to do more astrophotography over time. Sign up for OPT news, exclusive offers, and updates on the latest gear! 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. More aggressive reduction, or using these reducers with larger sensors, will result in aberrations and distortions near the edge of the image. Learn more about extra solar planets imagery, 3D Star rendering, observation planning, telescope control, multiple-panel printing, and much more. You can probably eke out 1.2 without noticing serious vignetting, which is a field stop of 31.5mm. Reducer - Corrector | Celestron I have had the Japan unit on the back of my C5 since 1994 or thereabouts. In the 1960s, Celestrons founder, Tom Johnson, created groundbreaking new telescopes never before seen on the consumer market. 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. I had a Celestron, Antares and Hirsch for awhile and compared them over about a year. I've seen some older threads saying that the Celestron, Meade and Antares FRs are all the same and manufactured in the same factory. 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. There is a way to make subjective data more useful and that way is proper blind, or better still. 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. But when not in the box or on the telescope, there is no cover for the other end. Designed distancing using the reducer with a 1.25 visual back and 1.25 Televue mirror diagonal; I really don't see any difference in the current crop except the "Meade" is usually the cheapest. F6.3 Focal reducer for F/10 or higher telescopes, 43mm aperture, 4-Element, Fully Multicoated. As one increases, the other decreases. As per the OP I still can't see any reason to buy the Celestron for significantly more $$$. The Antares focal reducer comes in small box. Our patented SkyAlign alignment technology makes setting up a computerized telescope simple, fast, and accurate. The stars at the edge could be worse or better. Once focused it's pretty good. Obviously bright objects like Jupiter or The Moon show the reflections. 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. I only have the Celestron f/6.3. Thks for that and its not for visual it for astrophotography. Wow, that is a very detailed discussion! Steve 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. It also leads to larger (although fainter) images of extended objects like the Moon or planets for astrophotographers or visual observers. For imaging, a T-adapter is threaded to the camera side of the focal reducer, which in turns connects to the camera with the appropriate hardware. It's important to match the back focus to within a millimeter or two to get an optimal image, especially with cameras with larger sensors. Since the focal length of the reducer, FR, is fixed, as d2 increases then MR decreases. because they really dont matter. It features a standard male SCT thread (2" OD, 24 TPI) on one side and a standard SCT female thread on the other. Thanks Peter! * Not a Retail Store * 16313 Arthur StreetCerritos, CA 90703, USA. There is one difference though the Antares came with only one lens cap whereas the Celestron had a cap for both ends. 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. External Focusers for Schmidt-Cassegrain Telescopes 3.1 The Basics of SCT Threads Some coma is visible in the corners, but the image is quite good for EAA applications. No negative issues to report. As a real-world example plot showing the above relationships, let's look at the 1.25" GSO focal reducer that provides a design reduction factor of 0.5x. 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 . That is definitely a 2" eyepiece, but it is not a large or long focal length 2" eyepiece. I've never found my 0.63 reducer causing CA when used with my SCT. October 11, 2010 in Discussions - Scopes / Whole setups. Focal reducers for many SCTs and their flat-field equivalents usually have a back-focus distance of 105mm. I've seen some older threads saying that the Celestron, Meade and Antares FRs are all the same and manufactured in the same factory. Therefore, a 55mm back focus with a filter that is 3mm thick added to the imaging train would become 56mm. In many cases, the answer is yes, especially for electronically-assisted astronomy (EAA). 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. 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. 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. One problem with getting opinions is that most of use do not have both reducers or have never done a side by side comparison. However, the export of some items may be restricted outside the US due to size or manufacturer restrictions. Celestrons award-winning Nature DX binocular gets a major upgrade with the addition of ED objective lenses. riklaunim Members 559 3,445 Location: Poland Posted October 11, 2010 They are reported as identical. Despite never removing it no matter what I was looking at. Does anyone have any experience with the Celestron and Antares focal reducers? Reducer Lens .7x - EdgeHD 800 Learn More. I'm going with the Celestron. No rainchecks will be issued for items out of stock at OPTcorp.com to match a competitor's price. 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). I've only used it a few times but it looks good to me. It's highly unlikely that they could be so precisely identical unless they were. Reproduction without permission prohibited. If the reducer is placed elsewhere, at a position called the operating distance, the focal reduction factor will not be as advertised. 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. Given the results of Test #1, I wanted to see if there was any truth to this assumption. USD $80.00. Optically, it consists of a four-element lens that is fully multi-coated for high contrast and resolution. Fortunately, my neighbors are not out in their backyards at 11 pm, or they may have thought I was torturing a small mammal. But in the Japan version I have never noticed any anomaly like the ghosting in the China R/C.
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