I doubt there is any difference between the Antares and the Celestron except price. Fumbling around in the dark, fine threads might be a problem. 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. It was also a little brighter in the center of the field with subtle darkening in the outer 20% or so. Again, to my surprise, there was absolutely no difference between the Celestron and Antares on any star. Who cares? 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 the diameter of the image circle decreases by a factor of 0.63 to about 24mm. 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. I'm going with the Celestron. Yellow and orange members of open clusters stood out a bit more as the various stars displayed their individuality. Hence, there is a chance that you may not be able to thread your SCT diagonal or other SCT accessory on to this reducer for these or for any other brand. 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. Celestron is considered better in terms of QA, less likely to come with free dust, hair or fingerprint. Fortunately, my neighbors are not out in their backyards at 11 pm, or they may have thought I was torturing a small mammal. The focus barely shifts between filters and I suspect any shifts I do get are down to the filters and changes in temp. To test this, I used three set-ups: 1. Focal reducers also move the effective focal plane of the objective inward, that is, towards the objective (see Figure 1). This would tell us exactly how well aberrations are corrected. Get ready for a night of astroimaging with your mount faster than previously thought possible with All-Star Polar Alignment. When using the diagonal, keep the field stops of the eyepieces under 20mm. I am a purely visual observer, so will evaluate for visual use only. 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. Increase that distance, and greater reduction results and visa versa. For me, I was looking for, and planning to keep, the one that yielded the greatest reduction. The Buyer's Guide To Eyepieces at the top of the Eyepieces forum has a column for this spec. 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. Such an image circle is still large enough to encompass the relatively large sensor of many deep-sky astronomy cameras. 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. Upon close inspection, it was clear that the housing of Antares assembled in Canada version was a little more substantial than the Celestron. 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. Please let us know what topics you are interested in. 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. 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. This innovative software solves the time-consuming problem of trying to pinpoint the North Celestial Pole. 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. 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. Thanks. If used with other f/ratios, the field flattening characteristic may be unpredictable. Reducer Lens .7x - EdgeHD 800 Possibly the design of the Antares was changed .. When you said, "in some cases" a focal reducer also works as a flattener/corrector, are you saying that not all focal reducers are flatteners/corrector? 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. In both cases will end with a similar tfov. 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. We have corrected # (iii) after equations 6 & 7. The visual back must be removed first. 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. 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. I have had the Japan unit on the back of my C5 since 1994 or thereabouts. If the reducer is placed closer to the eyepiece or camera than the distance D, the reduction factor decreases. But in the Japan version I have never noticed any anomaly like the ghosting in the China R/C. The working distance or required back focus, explained above, is usually specified and is far more important in practice. The reducer fits all Meade and Celestron . 160K views 9 years ago This video is a complete overview of focal reducers and how they function applying to telescopes. Since the Celestron and Antares are supposed to have different focal lengths and spacing specs, I expected different results. . This is very impressive performance given how hard this problem is to mitigate in general. Figure 2 shows the effective of a focal reducer on the light from a telescope objective. Planetarium software package which provides easy-to-understand explanations and impressive visuals of all kinds. No small animals were harmed in making these observations. It must be in stock at the time of Price Match for us to make a guarantee. Therefore, a 55mm back focus with a filter that is 3mm thick added to the imaging train would become 56mm. No retailers currently carry this product. Edited by bluewater, 05 September 2020 - 11:27 AM. Housings, threads, reduction, correction, blah, blah, blah. The equations in the Appendix show how this all works. I don't know. if the illuminated field is 27mm wide without the reducer, it will be 27 x 0.63 = 17mm with it in place. Meade once made an f/3.3 focal reducer for SCT scopes. 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. The lens has a knurled surface, providing a tremendous gripping surface for threading/unthreading. All Rights Reserved. It works fine but you should stick with 1.25 EPs; or can use 2" EPs without corrector. It has only one cover, which surprised me. I would not use the reducer with a 2" diagonal or eyepiece in the C6. This appendix summarizes how this works based on simple equations from the book Telescope Optics by Rutten and van Venrooij. Meade and Celestron both sell such SCT-T adapters with the correct optical length. 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. The Antares f6.3 focal reducer screws directly to the visual-back thread of all popular SCTs and converts f10 instruments to f6.3. Our patented SkyAlign alignment technology makes setting up a computerized telescope simple, fast, and accurate. I happily cycle through LRGB filters to build the image rather than do a whole run of one filter at a time. But I am rusty, can you condense a bit for me please? ), 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. You currently have javascript disabled. This filter threads on to the rear cell of your Celestron or Meade SCT telescope. 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. The most popular accessories for your new telescope! Focal Reducer, 2", 0.7X. DUE TO EXTREMELY HIGH DEMAND, WE WILL NOT BE TAKING NEW ORDERS UNTIL MONDAY, DECEMBER 14. Meade does not make an equivalent line of focal reducers for the ACF scopes, although some models of Meade ACF are already at f/8, faster than the f/10 ratio of Celestron Edge HD scopes. Celestrons aplanatic EdgeHD optics revolutionized astroimaging. The design reduction factor of a focal reducer is the relative amount by which the effective focal length of the telescope is reduced when the focal reducer is used at its specified working distance or back focus. First, let's have a look at some key optical parameters are needed to understand focal reducers. In most cases, the easiest option is to choose the focal reducer made specifically for your telescope. 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. Several functions may not work. But is there a difference in quality between the Antares and the Celestron or Meade focal reducers? Obviously bright objects like Jupiter or The Moon show the reflections. An eyepiece with a 27mm field stop yields a true field of 1.03 in the C6 at f/10. F6.3 Focal reducer for F/10 or higher telescopes, 43mm aperture, 4-Element, Fully Multicoated. As I understand it, compared to the old Meade SCT's, the ACF is already "coma corrected", so the standard Meade, Celestron etc F6.3 focal reducers are not suitable and will only worsen the images. Still not sure what is the right gear for you? The threads were similar on the eyepiece end, but a bit smoother. Sharpness is essentially the same. Meade once made an f/3.3 focal reducer for SCT scopes. Each focal reducer has a fixed specification called the working distance or required back focus. Never used one, but read the reviews here that suggest a coating problem. This rugged, 3-in-1 device features a true tactical 3-mode flashlight, a hand warmer, and a portable power bank for recharging your personal electronics on the go. I use the Celestron version and it seems OK for both visual and imaging. Thanks guys, appreciate the feedback. 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. It might work but it does not tell us anything about how well or to what extent the product works to correct the field of an SCT. Some faster refractors with a focal ratio of f/6, for example, only require field flatteners and not focal reducers. Take control of your telescope! 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. For me the Antares was a little brighter and had the least scatter by a bit so the better coatings won. By using this site, you agree to our Terms of Use. Most Feather Touch focusers cost between $300-$350. 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. So it provides a 0.63x design reduction factor when used with an f/10 SCT at the specified working distance. Thks for that and its not for visual it for astrophotography. They only publish the value of D, the working distance (sometimes called the back focus distance) and the design reduction factor MRD. There are also third-party vendors such as Hotech. 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. Please re-enable javascript to access full functionality. 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. Celestron Solar Safe filter technology is GUARANTEED SAFE for direct solar observation and has been independently tested by SAI Global Assurance Services. 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. . There will be no shipments on 3/1/2023, 3/2/2023, or 3/3/2023 (March 1st - March 3rd, 2023). Given the results of Test #1, I wanted to see if there was any truth to this assumption. 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. Manish Panjwani has been an active amateur astronomer since before Halley's Comet last flew by our neighborhood. These scopes are compatibles with focal reducers. Can you help me? You need to be a member in order to leave a comment. A useful thing to know is how far from the objective lens (for a refractor) is the focal reducer located. Stars in the corner of the image frame are indistinguishable between the Antares and the Celestron. Designed distancing using the reducer with a 1.25 visual back and 1.25 Televue mirror diagonal; In every configuration, there were essentially parfocal, requiring only a tiny fine focus adjustment when changing correctors. - thanks. A reducer is a set of converging (or positive) lenses that cause the light from a telescope objective to converge at a steeper angle to the focal plane as if it were coming from an objective with a faster (lower) focal ratio and a shorter focal length. That said any comparison reviews are helpful. Focal reducers are essential optical accessories for astrophotography, electronically-assisted astronomy (EAA), and in some cases, for visual observation with long focal ratio telescopes. The focal length and design working distance for this focal reducer were not available from the manufacturer. No difference. 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. control and Sky Viewer display makes selecting your target easy. 800-483-6287 Celestrons patented StarSense Technology makes it easier than ever to locate objects in the night sky, even if youve never used a telescope before. Copyright 2021 Stargazers Lounge But while the image gets brighter, the size of the image circle gets proportionately smaller. Maybe I got a lemon. 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. . Details: The item must be the identical item, brand name, size, weight, color, quantity and model number. 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. Optically, it consists of a four-element lens that is fully multi-coated for high contrast and resolution. At least these two units I tested make the answer - whatever. Brian Ventrudo is a writer, scientist, and astronomy educator. The female end attaches to the rear cell of the telescope. Bear in mind you can't squeeze blood out of a turnip, i.e. 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? The review is a subjective visual impression, which is interesting but not best evidence. However, doesn't fit in the telescope and even if it did wouldn't work. The price for an item/offer must be listed and valid at the time of match. 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. Increasing the operating distance, that is, moving a focal reducer away from the eyepiece or camera reduces its reduction factor, or conversely increases the amount of reduction. which looks like the same one. The resultant reduction factor was measured to be 0.46x. 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! Have always disliked the crude, noisy SCT threads, but I get it. Celestron or Antares? Melotte 15 - First Process in PixInsight (easy! 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. If you do so, you will achieve the design reduction factor. Focus misses by about 1 turnof the focus knob.Here is my solution:Buy a shorter 1.25 visual back for my scope. For example, a 0.8x reducer placed at the working distance provides a reduction of (1 0.8) x 100 = 20%. 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. All additional accessories mount onto the exterior/male threads. They are reported as identical. Enter it during checkout! More about this below. Can these economical focal reducers from GSO and other vendors result in good images? Easy solution found a very tiny dab of super lube on the threads and all was well and quiet.. The lens is housed in machined aluminum for are machined aluminum black anodized. The stars at the edge could be worse or better. USD $80.00. However, this also came at a cost, as the sky background in the Antares was slightly brighter. High power views will provide flatter fields all the way to the edge, both visually and photographically. It features a standard male SCT thread (2" OD, 24 TPI) on one side and a standard SCT female thread on the other. 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. 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. We have tested our current batch and it works with Meade, Celestron, and Baader SCT accessories. If used before or beyond the working distance, unwanted image distortion may result. Performance wise what differences might there be using the reducer on a smaller scope. External Focusers for Schmidt-Cassegrain Telescopes 3.1 The Basics of SCT Threads 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. Our proprietary StarBright XLT optical coatings dramatically increase transmission, up to 97.4% on our Schmidt corrector lenses. Wow, that is a very detailed discussion! The naming convention of SCT focal reducers is a little confusing. 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). * Not a Retail Store * 16313 Arthur StreetCerritos, CA 90703, USA. Is there likely to be any differences in performance between using these on an 8 or something smaller like my 6SE? Despite never removing it no matter what I was looking at. Now It only focuses near things, like some kind of macro zoom. It's usually specified in millimeters. Orders placed over the weekend will be shipped on the following Monday. However, it will not thread into William Optics accessories, and with GSO it is a hit or miss. I also used several eyepieces including the ES 24mm/68, 17.5mm and 12.5mm Morpheuses, and a 10.5mm Pentax XL. Photographically you also get a wider field and much shorter exposures. Hi. Images in the Celestron tended to appear ever-so-slightly dimmer (maybe? One focal reducer will not achieve optimum results with all types of telescopes, so there is no universal' focal reducer. Will not focus with the stuff I have. 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. Quite interestingly it bears the very same engravings of the Meade 4000 r/c (including "series 4000") except for "MEADE". 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. To further factor out my natural astigmatism (I normally wear glasses while observing), I did the tests with my regular progressive lenses, single vision glasses I use when observing, and naked eye. I found both to be very good. Yet, the Antares still easily and fully threaded without any hitches. A little longer light path with a 2 Baader click-lock, low profile 1.25 adapter, and the 1.25 diagonal; 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. A longer effective focal length leads to higher magnification with a given eyepiece for visual observers. 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. We will be glad to help. CPWI has an extensive object database, employs PointXP mount modeling, and more. You can probably eke out 1.2 without noticing serious vignetting, which is a field stop of 31.5mm. I focus using a moonlight electronic focuser and focusmax. For the best experience on our site, be sure to turn on Javascript in your browser. If you want to save a few buck watch the classifieds on CN. One of the most important factors in a telescope is its transmissionthe percentage of light that reaches the focal plane. 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 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. Also read the reviews here, including those at 4 stars. Again, swapping back and forth for a couple of hours on M44, M35, and several brighter stars, I examined the shape of specific stars near the edge of the field with both correctors. 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. These RC reducers cannot be used with other types of telescopes. I have an 8SE, and am thinking about getting a focal reducer. This also resulted in the clear aperture of the Antares being about 39-39.5mm, versus the Celestrons 41mm. 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. Sign up for a new account in our community. 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. Specially-designed focal reducers are available for use with these telescopes. 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). Field stop diameters are one of the specified specs of eyepieces. 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. If you place your camera at a different working distance, you will get a different reduction factor and perhaps unwanted distortion in the image. The two samples I have PERFORM IDENTICALLY. This should not be the case if they have their purportedly different focal lengths. Thanks for any advice or experience you could share. I really don't see any difference in the current crop except the "Meade" is usually the cheapest. Your mileage may vary. 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. InternetSales@optcorp.com, 800-483-6287 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. But the smaller image circle means there is a limit to the field stop of an eyepiece that can achieve an unvignetted image. Completely stuck, completely frustrated.
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