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Several functions may not work. Hmmm . 160K views 9 years ago This video is a complete overview of focal reducers and how they function applying to telescopes. This filter threads on to the rear cell of your Celestron or Meade SCT telescope. Reducer Lens .7x - EdgeHD 1100 Learn More. Over the course of a several nights of general observing, I swapped back and forth between the Antares and Celestron R/Cs on a wide variety of objects open clusters, brighter galaxies, a couple of nebulae, and globular clusters as well. Looking forward to the day when I can do a shoot-out between a Japan and China Celestron, just for kicks. JavaScript seems to be disabled in your browser. It was also a little brighter in the center of the field with subtle darkening in the outer 20% or so. 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. 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. During checkout, you may also be shown other optional faster shipping choices.US Customers in Hawaii and Alaska: Free shipping applies to almost all products. 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. These reducers can also be used for visual observing with SCT scopes with eyepieces with a field stop as large as 24-27mm. Celestrons FREE planetarium app is an astronomy suite that redefines how you experience the night sky. 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). 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. 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. Better images are also obtained when using these focal reducers at a reduction factor of 0.5x 0.8x, approximately. 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. I use the Celestron version and it seems OK for both visual and imaging. Rather than a direct side-by-side, I swapped the reducers so that I was using them on the exact same, well-collimated instrument. Optically, it consists of a four-element lens that is fully multi-coated for high contrast and resolution. 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. Reducer Lens .7x - EdgeHD 800 Learn More. I am a purely visual observer, so will evaluate for visual use only. Perhaps not exactly- there will be some uncertainty because of manufacturing tolerances and so forth, but it will be close. 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. 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. Reducer - Corrector Also read the reviews here, including those at 4 stars. But in the end they both do pretty much the same thing and it sounds like any performance difference is subtle. In this case, an additional T-adapter (with an optical length of 50mm) is needed to get the spacing correct for a DSLR or other camera with a 55mm back focus. We reserve the right to verify a competitor's advertised price and the availability of the item. For me the Antares was a little brighter and had the least scatter by a bit so the better coatings won. 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. There is one difference though the Antares came with only one lens cap whereas the Celestron had a cap for both ends. * Not a Retail Store * 16313 Arthur StreetCerritos, CA 90703, USA. 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. I had a Celestron, Antares and Hirsch for awhile and compared them over about a year. They are reported as identical. Is that distance D= Fo-d1=Fo-(d2/MR)? 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. Does anyone know if the Antares 4000 focal reducer is as good as the Celestron focal reducer. But nearly every observer who installs one of these devices is pleased with their performance. Please Log in to save it permanently. Never noticed any anomalies with this unit. When the camera sensor is placed at this distance, the reduction factor of these reducers is 0.75x. Your mileage may vary. 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. Not noticed any optical problems. Many focal reducers are meant to be used within a few millimeters of the specified working distance to achieve the best possible image results. If it's positioned further from the eyepiece or camera and closer to the telescope objective, the reduction factor increases. However, the China 6.3 R/C has noticeable internal reflections that I haven't figured out yet. 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. 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. Some coma is visible in the corners, but the image is quite good for EAA applications. Stars had a tiny bit more sparkle and pop. 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. I think that the FRs made in Japan in the day may have been better. All Rights Reserved. During check-out, you will be presented with several shipping choices and costs. The focus barely shifts between filters and I suspect any shifts I do get are down to the filters and changes in temp. 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. When using the diagonal, keep the field stops of the eyepieces under 20mm. I have had the Japan unit on the back of my C5 since 1994 or thereabouts. However, this also came at a cost, as the sky background in the Antares was slightly brighter. If yes, what kind of focal reducers can I use? All Rights Reserved. External Focusers for Schmidt-Cassegrain Telescopes 3.1 The Basics of SCT Threads 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. However, it will not thread into William Optics accessories, and with GSO it is a hit or miss. So ab6110 is asking for a FR only without coma correction, there are a couple of brands who make special reducers for the ACF. Enter it during checkout! It works fine but you should stick with 1.25 EPs; or can use 2" EPs without corrector. Does anyone have any experience with the Celestron and Antares focal reducers? * Not a Retail Store * 16313 Arthur StreetCerritos, CA 90703, USA, Availability: Item has been discontinued by Agena and we no longer carry this item. The review is a subjective visual impression, which is interesting but not best evidence. Reviews. Reducer Lens .7x - EdgeHD 925 CPWI has an extensive object database, employs PointXP mount modeling, and more. If the reducer is placed closer to the eyepiece or camera than the distance D, the reduction factor decreases. 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 working distance (backfocus) of the Celestron f/6.3 reducer is specified to be 105mm from the base of the male SCT thread on the camera side. Easy solution found a very tiny dab of super lube on the threads and all was well and quiet.. The equations in the Appendix show how this all works. A few people have reported issues with the male SCT thread diameter on this item being a bit larger than necessary. Who cares? In every configuration, there were essentially parfocal, requiring only a tiny fine focus adjustment when changing correctors. A slight nod to the Antares for heft and higher transmission, but points to the Celestron for nice threads and better contrast. CPWI has an extensive object database, employs PointXP mount modeling, and more. We do not price match competitors if they are out of stock. If used before or beyond the working distance, unwanted image distortion may result. Images in the Celestron tended to appear ever-so-slightly dimmer (maybe? 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. 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! 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. Things change but when I rebought I got an Antares and it seems about the same to me. The Antares is supposed to be pretty comparable. This is the simplest way to attach your ASI121 to your telescope. This article explains the basics of how focal reducers work with an astronomy telescope. If a stronger level of focal reduction is used, say 0.5x, then the image circle may be too small to fill the sensor of larger cameras. 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 two samples I have PERFORM IDENTICALLY. I have this one Opticstar F6.3 Focal Reducer / Corrector. I have an 8SE, and am thinking about getting a focal reducer. 2023 Celestron, LLC. OPT Product Number: AE-SCTFR specifications Warranty 2 Year Warranty Works as advertised! I think I remember hearing the reduction factor is slightly different, cant remember more or less reduction. No small animals were harmed in making these observations. There are also third-party vendors such as Hotech. Both exhibited consistent reduction, identical field flattening, and edge correction properties, and both were high quality optically and mechanically. With the Celestron Reducer/Corrector Lens, thats precisely what you get. 3. I've only used it a few times but it looks good to me. You need to be a member in order to leave a comment. The telescope side of the barrel is often threaded with an M48 x 0.75 thread for standard 2" astronomy filters. I have a made in Japan 6.3 R/C and a made in China 6.3 R/C. 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. 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. More aggressive reduction, or using these reducers with larger sensors, will result in aberrations and distortions near the edge of the image. 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. Imagine having two telescopes in one a long focal length instrument for lunar and planetary work and a short focal length scope for deep sky observing and astrophotography. No retailers currently carry this product. However, these will not impact optical performance. The working distance or required back focus, explained above, is usually specified and is far more important in practice. The reducer features fully coated optics in an anodized aluminum filter ring with an ergonomic rubber grip. 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. I have the Antares and have no complaints. 2. Figure 7 shows an example of an image of the Dumbbell Nebula taken with a 1.25" GSO focal reducer at a reduction factor of 0.63x with an 85mm f/7 refractor and a QHY5III-290M camera with a sensor with a 6.4mm diagonal. 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).