Fortunately, my neighbors are not out in their backyards at 11 pm, or they may have thought I was torturing a small mammal. As a consequence, the standard f/6.3 and f/3.3 focal reducers for SCT scopes do not work. So, this past week I challenged the Antares and Celestron models to a head-to-hear on my C8 on some decent nights of good seeing and transparency in my Bortle 5-6 urban skies. For this shoot-out, I used a standard Celestron C8 with Starbright coatings. All Rights Reserved. You may need spacers or a T-adapter to ensure the correcting working distance. Add a 0.63x reducer, and the brightness of extended objects increases by (1/0.63)2 = 2.5. Please Log in to save it permanently. Many reducers, such as the Celestron HD focal reducer mentioned above, and many focal reducers for apochromatic refractors, are meant to be used within a few millimeters (or less) of the specified working distance to achieve the best possible image results. ED stands for "extra-low dispersion," which refers to the composition and optical properties of the glass used for the lenses. control and Sky Viewer display makes selecting your target easy. However, these will not impact optical performance. Designed distancing using the reducer with a 1.25 visual back and 1.25 Televue mirror diagonal; Orders placed over the weekend will be shipped on the following Monday. Theres a long-running debate in these forums and even statements from some reputable dealers that the Antares is just a reducer (even though it is labeled Reducer/Corrector), whereas the Celestron is a true R/C, which flattens the SCTs naturally curved field and provides some edge correction. Sign up for our newsletter to get exclusive deals, observing tips, and new product announcements. Reproduction without permission prohibited. 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. 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. Download the Celestron PWI Telescope Control Software. 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. Figure 1 shows the relationship between the focal reduction factor MR and the position of the reducer in the optical path. If the reducer is placed closer to the eyepiece or camera than the distance D, the reduction factor decreases. This filter threads on to the rear cell of your Celestron or Meade SCT telescope. The Antares is supposed to be pretty comparable. Does anyone have any experience with the Celestron and Antares focal reducers? I was referring to the C6 to answer you specifically. At a significantly lower price point, the Antares is a steal, and theres no need to upgrade to the Celestron if you already have one. These reducers can also be used for visual observing with SCT scopes with eyepieces with a field stop as large as 24-27mm. 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. As one increases, the other decreases. 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"). There are many different types of focal reducers and they all effect. How does it look thats what matters. Reducer Lens .7x - EdgeHD 1400 Learn More. For visual use, this means you get lower power with the same eyepiece and a wider field of view. This is very impressive performance given how hard this problem is to mitigate in general. 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. It must be in stock at the time of Price Match for us to make a guarantee. But is there a difference in quality between the Antares and the Celestron or Meade focal reducers? In your opinion, is the Celestron is worth the added cost ($150 vs. $90)? For example, a 0.8x reducer placed at the working distance provides a reduction of (1 0.8) x 100 = 20%. The equations in the Appendix show how this all works. 2023 Celestron, LLC. But the smaller image circle means there is a limit to the field stop of an eyepiece that can achieve an unvignetted image. Read our 101 article or get in touch. Besides observing from his heavily light polluted backyard in Los Angeles, Manish enjoys conducting astronomy outreach programs in local schools. Celestrons award-winning Nature DX binocular gets a major upgrade with the addition of ED objective lenses. 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. DUE TO EXTREMELY HIGH DEMAND, WE WILL NOT BE TAKING NEW ORDERS UNTIL MONDAY, DECEMBER 14. When using the diagonal, keep the field stops of the eyepieces under 20mm. For the best experience on our site, be sure to turn on Javascript in your browser. Telescope Optics, Rutten and van Venrooij, Chapter 15, Willman-Bell (1988). 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. 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. This would tell us exactly how well aberrations are corrected. Meade and Celestron both sell such SCT-T adapters with the correct optical length. Try & buy if you like - usual mates rates. Celestrons aplanatic EdgeHD optics revolutionized astroimaging. The price for an item/offer must be listed and valid at the time of match. 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. In every configuration, there were essentially parfocal, requiring only a tiny fine focus adjustment when changing correctors. 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. If you place your camera at a different working distance, you will get a different reduction factor and perhaps unwanted distortion in the image. Celestrons FREE planetarium app is an astronomy suite that redefines how you experience the night sky. Sharpness is essentially the same. Thanks guys, appreciate the feedback. 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. But in the end they both do pretty much the same thing and it sounds like any performance difference is subtle. SKU: CEL-94245. 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. The nominal design reduction factor of these reducers is typically 0.5x. High power views will provide flatter fields all the way to the edge, both visually and photographically. 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. Hi - most interesting - may I ask .. the brighter guys - "if a camera sensor is too small for a n adaper, will a focal reduer allow me to get greater use from the camera? Yellow and orange members of open clusters stood out a bit more as the various stars displayed their individuality. Please let us know what topics you are interested in. Thank you so much for the informative article, I now understand better how to integrate my reducer into my system to get better performance. The lens that the ZWO comes with give a perfect wide angle image of what is in front of it. I'd favor the Japanese Celestron version over the others that are commercially available. It was also a little brighter in the center of the field with subtle darkening in the outer 20% or so. I focus using a moonlight electronic focuser and focusmax. Some third-party vendors also make reducers for SCT scopes. We do not price match competitors if they are out of stock. Meade once made an f/3.3 focal reducer for SCT scopes. The Reducer/Corrector can also be used for terrestrial digiscoping. The visual back must be removed first. 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. As another example,GSO makes focal reducers for their line of Ritchey-Chretien imaging telescopes. Therefore, a 55mm back focus with a filter that is 3mm thick added to the imaging train would become 56mm. However, the export of some items may be restricted outside the US due to size or manufacturer restrictions. This article explains the basics of how focal reducers work with an astronomy telescope. Perfect for the serious student, professional scientist and discriminating hobbyist. 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. 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. During check-out, you will be presented with several shipping choices and costs. 2. 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. 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. (Note: Using the simple equations above, the focal length of this reducer can be estimated to be about 350mm). 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. The click-lock with a 2 dielectric diagonal with a somewhat shorter light path, using both a 2 ES 28mm/68 and the same low-profile adapter with a 1.25 ES 24mm/68. Also, the focusers of most Newtonians do not have enough in-travel to accommodate a focal reducer. 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. This factor is designated by a power that is less than 1, and it usually lies between 0.5x or 0.8x. 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. Field stop diameters are one of the specified specs of eyepieces. They never really recovered from selling a few 15 years back with element reversed. As a Barlow's magnification increases with increasing distance from the Barlow, a focal reducer's reduction increases with increasing distance from the reducer. With the barrel 1.25 reducer won't focus, all I get is fuzzy snowballs. 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! The Antares FR2-0.7X is the same 4-element f/6.3 lens system used for f/10 Schmidt-Cassegrain telescopes but in a 2" barrel threaded for standard filters. Focal Reducer, 2", 0.7X. When the camera sensor is placed at this distance, the reduction factor of these reducers is 0.75x. Possibly the design of the Antares was changed .. This "speeds up" the optical train by reducing the focal length and magnification of the scope, requiring less time to integrate the same signal. In some cases, focal reducers also act as field flatteners by correcting for field curvature and coma of the objective lens. Whereas the Celestron threaded smoothly onto the scope, the Antares chattered and squeaked a bit more so when being removed. It can also be used with any other small chip CCD camera having a 1.25" nosepiece, such as the Celestron NexImage, Meade DSI . I even lost track of which reducer I was using. Request stock alerts and we'll let you know when the item is back in stock. 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. 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. Start here to find the perfect telescope for you! This fully multi-coated lens provides maximum light transmission with near full-field illumination. Our proprietary StarBright XLT optical coatings dramatically increase transmission, up to 97.4% on our Schmidt corrector lenses. 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. That is definitely a 2" eyepiece, but it is not a large or long focal length 2" eyepiece. This focal reducer is made to attach to the rear cell of Schmidt-Cassegrain or Maksutov-Cassegrain telescopes. An eyepiece with a 27mm field stop yields a true field of 1.03 in the C6 at f/10. Figure 6 shows a 1.25" focal reducer from GSO configured with a ZWO ASI224MC camera. 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 only have the Celestron f/6.3. No difference. 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. But while the image gets brighter, the size of the image circle gets proportionately smaller. 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. For the best experience on our site, be sure to turn on Javascript in your browser. You attach the focal reducer to the rear port on a SCT and can keep it covered. There will be no shipments on 3/1/2023, 3/2/2023, or 3/3/2023 (March 1st - March 3rd, 2023). Equation 6 & 7 item two & three does not make sense, both say increase its reduction (one should say reduce its reduction?). 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. It is not a corrector or flattener. But in the Japan version I have never noticed any anomaly like the ghosting in the China R/C. Thanks Peter! I've never found my 0.63 reducer causing CA when used with my SCT. 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. We will match any online price that we confirm as valid. My experience is that CN sellers are way above those listing elsewhere. A former wireless communications consulting engineer and management consultant to various Fortune 500 companies, Manish started Agena AstroProducts in 2003. I've looked through one from Meade and first impression was that it was like the Celestron version. Unlike . I had a Celestron, Antares and Hirsch for awhile and compared them over about a year. We only send interesting emails and will never sell your data. 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. * Not a Retail Store * 16313 Arthur StreetCerritos, CA 90703, USA. 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. The working distance or required back focus, explained above, is usually specified and is far more important in practice. Celestron Solar Safe filter technology is GUARANTEED SAFE for direct solar observation and has been independently tested by SAI Global Assurance Services. More about this below. 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. No idea what the issue is. Years ago, I bought the Antares version, and moved over to the Celestron. Assuming you use the reducer with the stock 1.25" diagonal, it will operate at f/6.3. They provide 0.75x focal reducers for these telescopes that takes an f/8 instrument down to f/6. JavaScript seems to be disabled in your browser. The reducer fits all Meade and Celestron . A slight nod to the Antares for heft and higher transmission, but points to the Celestron for nice threads and better contrast. Thanks guys, I'm trying to get my ZWO ASI120MC-S to work with my 90mm Meade. This is the simplest way to attach your ASI121 to your telescope. Most different was that the sky background was a little darker and more uniform, providing a tiny contrast boost for fainter objects. The female end attaches to the rear cell of the telescope. 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. If used before or beyond the working distance, unwanted image distortion may result. Contiguous US Customers:All items we sell ship for free within the Contiguous US. 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. 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. 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. Photographically you also get a wider field and much shorter exposures. Enter it during checkout! 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. Michael 1 ronin Members They both are great and I doubt my eyes could detect a difference in any one of them including the Japan version. Is there likely to be any differences in performance between using these on an 8 or something smaller like my 6SE?
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