Have always disliked the crude, noisy SCT threads, but I get it. 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. if the illuminated field is 27mm wide without the reducer, it will be 27 x 0.63 = 17mm with it in place. That includes, for example, a 1.25" eyepiece with an apparent field of view of 68 and a focal length of 24mm (eg. 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. It must be in stock at the time of Price Match for us to make a guarantee. The resultant reduction factor was measured to be 0.46x. The distance d2, which measures the position of the new focal plane of the objective from the back of the focal reducer is given by Equation 5: In these equations, d1, d2, and MR are all variables that depend on each other through Equations 2 and 4. Regardless, the difference was miniscule and is more than adequate on both and exceeds a 8 or 6 SCTs baffle tube diameter. The Antares focal reducer comes in small box. 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. Celestron or Antares? Yet, the Antares still easily and fully threaded without any hitches. Never noticed any anomalies with this unit. Again, to my surprise, there was absolutely no difference between the Celestron and Antares on any star. I also used several eyepieces including the ES 24mm/68, 17.5mm and 12.5mm Morpheuses, and a 10.5mm Pentax XL. The reducer is we might presume designed to correct to some as yet un-measured extent, the image of a standard SCT. control and Sky Viewer display makes selecting your target easy. But the diameter of the image circle decreases by a factor of 0.63 to about 24mm. - thanks. An image of about 24mm across, approximately, allows an observer to use a 1.25" eyepiece with a maximal field stop. We have tested our current batch and it works with Meade, Celestron, and Baader SCT accessories. More about this below. Blue Fireball M42 T/T2 Thread Camera Adapter for Prime Focus Photography - 2" # P-06, Celestron T-Ring for Canon EOS Camera # 93419, GSO 2" Crayford Focuser for SCTs - Dual Speed, Length of male SCT thread = 5mm (0.2") but this is preceded by an unthreaded part on the eyepiece side making the total length = 8.8mm (0.35"), Length of female SCT thread = 7.5mm (0.3"). The same illumination you have at the edge of a 27mm field, the C8 has at the edge of a 38mm field. When the camera sensor is placed at this distance, the reduction factor of these reducers is 0.75x. Telescope Optics, Rutten and van Venrooij, Chapter 15, Willman-Bell (1988). 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. I have a made in Japan 6.3 R/C and a made in China 6.3 R/C. 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 am a purely visual observer, so will evaluate for visual use only. Celestrons patented StarSense Technology makes it easier than ever to locate objects in the night sky, even if youve never used a telescope before. These reducers can also be used for visual observing with SCT scopes with eyepieces with a field stop as large as 24-27mm. 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. If you place your camera at a different working distance, you will get a different reduction factor and perhaps unwanted distortion in the image. What an enjoyable read and detailed comparison. Since then, Agena has become one of the leading online retailers of telescopes and astronomical accessories worldwide. Figure 6 shows a 1.25" focal reducer from GSO configured with a ZWO ASI224MC camera. A former wireless communications consulting engineer and management consultant to various Fortune 500 companies, Manish started Agena AstroProducts in 2003. I think there may be some confusion here, because Antares makes a variety of reducers for eyepieces and scopes in addition to this SCT R/C but this definitely is a reducer/corrector. * Not a Retail Store * 16313 Arthur StreetCerritos, CA 90703, USA. There are many different types of focal reducers and they all effect. Thanks guys, I'm trying to get my ZWO ASI120MC-S to work with my 90mm Meade. Now It only focuses near things, like some kind of macro zoom. No rainchecks will be issued for items out of stock at OPTcorp.com to match a competitor's price. Contiguous US Customers:All items we sell ship for free within the Contiguous US. Can these economical focal reducers from GSO and other vendors result in good images? Some faster refractors with a focal ratio of f/6, for example, only require field flatteners and not focal reducers. Clearly cost is a big factor for satisfied users. Go behind the scenes with Celestrons product development team and learn more about our award-winning and patented innovations. It has only one cover, which surprised me. The Buyer's Guide To Eyepieces at the top of the Eyepieces forum has a column for this spec. 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. Generally, views through the Antares seemed a little more transparent and brighter. That was fun. The Celestron is both a corrector and focal reducer and the Antares is just a focal reducer. 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. No idea what the issue is. However, it will not thread into William Optics accessories, and with GSO it is a hit or miss. Opticstar F6.3 Focal Reducer / Corrector. Field stop diameters are one of the specified specs of eyepieces. Your wishlist has been temporarily saved. . But nearly every observer who installs one of these devices is pleased with their performance. If yes, what kind of focal reducers can I use? DUE TO EXTREMELY HIGH DEMAND, WE WILL NOT BE TAKING NEW ORDERS UNTIL MONDAY, DECEMBER 14. Reducer Lens .7x - EdgeHD 1400 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. Steve I wont bother with differences in packaging, caps, etc. This is the simplest way to attach your ASI121 to your telescope. Anyway, when purchased my R/C the "original" Celestron unit was not readily available and was offered instead the one sold under the shop's own label (in my case Tecnosky, but I saw the same product offered under TS label). 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). 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 However, these will not impact optical performance. 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. Style: Product Details. Some are available in 1.25" barrel format but with C threads. The naming convention of SCT focal reducers is a little confusing. 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. If you want to save a few buck watch the classifieds on CN. I doubt there is any difference between the Antares and the Celestron except price. These RC reducers cannot be used with other types of telescopes. External Focusers for Schmidt-Cassegrain Telescopes 3.1 The Basics of SCT Threads Nada. Download the Celestron PWI Telescope Control Software. Hello! 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. ED glass is specially formulated and contains rare-earth compounds that greatly reduce a visual defect called chromatic aberration. Meade once made an f/3.3 focal reducer for SCT scopes. The Reduction Factor and the Amount of Reduction are inversely related. These reducers can also be used for visual observing with SCT scopes with eyepieces with a field stop as large as 24-27mm. This should not be the case if they have their purportedly different focal lengths. Several functions may not work. This focal reducer is made to attach to the rear cell of Schmidt-Cassegrain or Maksutov-Cassegrain telescopes. 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. WiFi technology encircles the globe in a web of connectivity, knowledge, and information. Orders placed after 12:00 PM Pacific Time will be shipped the next business day. Images made with my ZWO 533 camera testing both show them to be essentially the same. If used before or beyond the working distance, unwanted image distortion may result, especially when using cameras with larger sensors. I have the Antares and have no complaints. If I had to guess, the difference is maybe 10-15 grams. 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. a Tele Vue Panoptic), or a Plossl eyepiece with an apparent field of view of 50 and a focal length of 32mm. Because of their distinct optical design, slower Schmidt-Cassegrain telescopes (SCT) with focal ratios of f/10 require a different design of focal reducer compared to refractors. You need to be a member in order to leave a comment. 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. I found both to be very good. Things change but when I rebought I got an Antares and it seems about the same to me. We only send interesting emails and will never sell your data. Start Chat One problem with getting opinions is that most of use do not have both reducers or have never done a side by side comparison. Even though they may have been slightly dimmer, galaxies were a bit easier to tease out of the urban light soup I deal with. As a Barlow's magnification increases with increasing distance from the Barlow, a focal reducer's reduction increases with increasing distance from the reducer. In terms of reduction and correction which are what reducer/correctors are supposed to do both are superb. Reducer - Corrector 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. I have a Raspberry HQ camera, a Sony TV Zoom 12.5-75mm f1.8 and a Astromania 1,25" 0.5x focal reducer. Just one question. For the best experience on our site, be sure to turn on Javascript in your browser. 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 I am rusty, can you condense a bit for me please? This filter threads on to the rear cell of your Celestron or Meade SCT telescope. If the reducer is placed closer to the eyepiece or camera than the distance D, the reduction factor decreases. Have a promo code? 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. It's usually specified in millimeters. I've never found my 0.63 reducer causing CA when used with my SCT. So, if you have a filter that is 3mm thick, you need to add 1mm of spacing to your imaging train to retain the correct back focus. I use it on my C8 SCT with a 1000d, and it seems to do everything written on the tin. 2. Figure 2 shows the effective of a focal reducer on the light from a telescope objective. In many cases, the answer is yes, especially for electronically-assisted astronomy (EAA). 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. 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. The focal length of a focal reducer is usually measured from the rear lens surface of the reducer (and not the reducer's housing). For me the Antares was a little brighter and had the least scatter by a bit so the better coatings won. The nominal design reduction factor of these reducers is typically 0.5x. Benefits limited to hardware and conditions? For imagers, the main purpose of a focal reducer is to increase the brightness of the image at the focal plane. Dedicated focal reducers for refractors are intended primarily for imaging, not visual observation. 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. Brian Ventrudo is a writer, scientist, and astronomy educator. Michael 1 ronin Members Each focal reducer has a fixed specification called the working distance or required back focus. 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. Your price: $579.00. 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. This article explained the basics of how focal reducers work with various kinds of telescopes and how their working distance affects their reduction factor, and it provided sufficient detail to help amateur astronomer choose and use the right focal reducer for a particular application. Today, our world-class team of optical and electronic engineers continues to push the boundaries of technology. The faster f/ratio allows you to use slower film or shoot in lower light level situations and still properly expose your subject. 1.2" in that scope is a field stop of 43mm at f/10 and 27mm at f/6.3. This innovative software solves the time-consuming problem of trying to pinpoint the North Celestial Pole. In the 1960s, Celestrons founder, Tom Johnson, created groundbreaking new telescopes never before seen on the consumer market. Explore Scientific Keys to the Universe Sale. Reducer Lens .7x - EdgeHD 800 If it's positioned further from the eyepiece or camera and closer to the telescope objective, the reduction factor increases. Read our guide! For this test, I used a single configuration R/C, Click-lock, and 1.25 diagonal with the adapter. 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. We reserve the right to verify a competitor's advertised price and the availability of the item. 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. Here, there was a subtle difference . These scopes are compatibles with focal reducers. Enter it during checkout! Sign up to get exclusive deals, observing tips, and new product announcements. 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. 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. With both, using the same diagonal set-up, the exact same stars were visible at the very edge of the FOV. I have Hirsch focal reducer, which is yet another clone of the Celestron reducer. Celestron or Antares f/6.3 focal reducer for SCT? The internal surfaces are blackened and glare-threaded to provide the highest contrast. 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. Since the Celestron and Antares are supposed to have different focal lengths and spacing specs, I expected different results. This fully multi-coated lens provides maximum light transmission with near full-field illumination. Assuming you use the reducer with the stock 1.25" diagonal, it will operate at f/6.3. Just point the telescope at any three bright objectsstars, bright planets, or even the Moonand your telescope can orient itself with the night sky. Once installed, you can add additional accessories like T-Adapters, 1.25 Visual Back, Star Diagonal, or Off-Axis Guider. This is the distance at which the reducer must be placed in front of the eyepiece or camera focal plane in order to operate at the design reduction factor. Celestron Focus Motor for SCT, EdgeHD & 8" RASA, Celestron C6 0.63 reducer/flattener back focus. Very helpful, thanks a lot for this article! ), ASI Air Plus - Connected items are 'greyed out', Cost of ordering used equipment U.S. - Can can more than double figure, Tuthill Isostatic Mount and Star Trap Power Module. Easy solution found a very tiny dab of super lube on the threads and all was well and quiet.. SKU: CEL-94245. CEL-94245. The focus barely shifts between filters and I suspect any shifts I do get are down to the filters and changes in temp. CPWI has an extensive object database, employs PointXP mount modeling, and more. We process your personal data as stated in our. Reducer Lens .7x - EdgeHD 1100. Figure 1 shows the relationship between the focal reduction factor MR and the position of the reducer in the optical path. But while the image gets brighter, the size of the image circle gets proportionately smaller. They never really recovered from selling a few 15 years back with element reversed. However, manufacturers virtually never provide this specification. Your eyepieces are the first accessories you should learn to use with your telescope. Most focal reducers are designed to operate optimally at the working distance in the optical path to achieve their specified reduction factor, which is usually between 0.5x and 0.8x. JavaScript seems to be disabled in your browser. 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. Edited by Tony Bonanno, 16 April 2021 - 06:44 PM. There will be no shipments on 3/1/2023, 3/2/2023, or 3/3/2023 (March 1st - March 3rd, 2023). High power views will provide flatter fields all the way to the edge, both visually and photographically. EclipSmart solar products feature Solar Safe filter technology providing the ultimate protection from harmful solar radiation, including both IR and UV light, and filters 99.999% of visible light. Reducer Lens .7x - EdgeHD 1100 Learn More. One of the most important factors in a telescope is its transmissionthe percentage of light that reaches the focal plane. This also resulted in the clear aperture of the Antares being about 39-39.5mm, versus the Celestrons 41mm. Most reducers have a design reduction factor, MRD, that assumes the reducer is placed at a specific working distance, D, from the back surface of the focal reducer itself. No results, please adjust your filters. The female end attaches to the rear cell of the telescope. I have the Japanese version and although I haven't used it in quite awhile, the views through it were superb with no internal reflections at all. All Rights Reserved. During check-out, you will be presented with several shipping choices and costs. A few large telescopes and mounts are excluded from this free shipping offer. No small animals were harmed in making these observations.