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These reducers can also be used for visual observing with SCT scopes with eyepieces with a field stop as large as 24-27mm. The female end attaches to the rear cell of the telescope. Another factor to consider: focal reducers also increase the angle at which light approaches the focal plane. The same illumination you have at the edge of a 27mm field, the C8 has at the edge of a 38mm field. Focal reducers for refractors are easy to use. I have a Raspberry HQ camera, a Sony TV Zoom 12.5-75mm f1.8 and a Astromania 1,25" 0.5x focal reducer. Will not focus with the stuff I have. Newtonian reflectors will seldom be able to accommodate the in-focus travel demanded by focal reducers. Focal reducers for refractors with focal ratio of f/7 to f/9, roughly, have a design reduction factor of about 0.75x to 0.8x and produce a flat field by correcting for the curvature of the objective lens. Read our 101 article or get in touch. Can you tell me about the use of reducers in Maksutov-Cassegrain telescopes? With both, using the same diagonal set-up, the exact same stars were visible at the very edge of the FOV. Some manufacturers will specify the working distance from the middle of the rear lens surface, and this number must then be converted into a practical working distance number by subtracting the amount by which the rear lens surface is recessed in its housing. I have both the Antares and the Celestron reducers. 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. Here, there was a subtle difference . 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. Equation (4) shows the relationship between the distance d2 and the reduction factor MR. Since 2008, Brian has taught astronomy to tens of thousands of stargazers through his websites OneMinuteAstronomer.com and CosmicPursuits.com. Reducer - Corrector Learn More. 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. More important, its clear that the Antares is a reducer/corrector, just like the Celestron and not merely a reducer. Ive owned Celestron, Meade, and Antares models over the years at least a couple of each. CPWI has an extensive object database, employs PointXP mount modeling, and more. I wish there was. Unleash the full pointing accuracy of your Celestron computerized telescope with a specialized telescope control software suite. For this shoot-out, I used a standard Celestron C8 with Starbright coatings. I use the same back spacing for both on a small 6" Celestron SCT. Read our guide! I have an 8SE, and am thinking about getting a focal reducer. InternetSales@optcorp.com. You also wont be unhappy spending the few extra bucks on the Celestron for the pretty orange lettering, particularly if you can pick one up used, as I did. It is recommended for . Reducer Lens .7x - EdgeHD 925 As a Barlow's magnification increases with increasing distance from the Barlow, a focal reducer's reduction increases with increasing distance from the reducer. 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. In many cases, the answer is yes, especially for electronically-assisted astronomy (EAA). Some faster refractors with a focal ratio of f/6, for example, only require field flatteners and not focal reducers. Thanks for pointing this out. This is a. October 11, 2010 in Discussions - Scopes / Whole setups. Nowadays I tend to use the Celestron more with my refractors for imaging and viewing. I also used several eyepieces including the ES 24mm/68, 17.5mm and 12.5mm Morpheuses, and a 10.5mm Pentax XL. The Celestron f/6.3 is ~150 compared to the Antares at ~70. For me the Antares was a little brighter and had the least scatter by a bit so the better coatings won. It seems right to put some distance between the camera and the focal reducer, right? The threads were similar on the eyepiece end, but a bit smoother. All rights reserved. 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. 3. InternetSales@optcorp.com, 800-483-6287 Sign up for our newsletter to get exclusive deals, observing tips, and new product announcements. 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. All Rights Reserved. As another example,GSO makes focal reducers for their line of Ritchey-Chretien imaging telescopes. As per the OP I still can't see any reason to buy the Celestron for significantly more $$$. Turn it on and push Align. In about three minutes, youre ready to observe! The resultant reduction factor was measured to be 0.46x. 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. Have always disliked the crude, noisy SCT threads, but I get it. We do not price match competitors if they are out of stock. No difference. Thanks guys, I'm trying to get my ZWO ASI120MC-S to work with my 90mm Meade. On the camera side, the focal reducer has male M42x0.75 or M48x0.75 threads that attach directly to the T-ring (with an M42-M48 adapter if necessary). Upon close inspection, it was clear that the housing of Antares assembled in Canada version was a little more substantial than the Celestron. In these equations: The combined focal length of the objective and focal reducer is given by Equation 1: For example, when d1=0, that is, the focal reducer is at the focal plane of the objective, Fcomb=Fo, so the focal reducer has no effect. Completely stuck, completely frustrated. Sign up for our newsletter to get exclusive deals, observing tips, and new product announcements. Very helpful, thanks a lot for this article! The reducer features fully coated optics in an anodized aluminum filter ring with an ergonomic rubber grip. I'm going with the Celestron. Nada. Also read the reviews here, including those at 4 stars. 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. Because I have not heard any complaints about the made in China R/C. 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 innovative software solves the time-consuming problem of trying to pinpoint the North Celestial Pole. Most manufacturers provide this specification. They never really recovered from selling a few 15 years back with element reversed. 800-483-6287 As one increases, the other decreases. If used with other f/ratios, the field flattening characteristic may be unpredictable. The lens that the ZWO comes with give a perfect wide angle image of what is in front of it. This filter threads on to the rear cell of your Celestron or Meade SCT telescope. SKU: CEL-94245. 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. 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. JavaScript seems to be disabled in your browser. However, these will not impact optical performance. It is not a corrector or flattener. and you will be fine. The lens is housed in machined aluminum for are machined aluminum black anodized. The Antares focal reducer comes in small box. Right off the bat, I was struck by how similar the two R/Cs were. 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. 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. Explore Scientific - Keys to the Universe Sale. Many focal reducers for refractors have a working distance (or back focus distance) of 55mm. . Things change but when I rebought I got an Antares and it seems about the same to me. ), 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. Also, the focusers of most Newtonians do not have enough in-travel to accommodate a focal reducer. Both exhibited consistent reduction, identical field flattening, and edge correction properties, and both were high quality optically and mechanically. 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. Celestrons award-winning Nature DX binocular gets a major upgrade with the addition of ED objective lenses. Can you help me? 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. I happily cycle through LRGB filters to build the image rather than do a whole run of one filter at a time. Sign up to get exclusive deals, observing tips, and new product announcements. The Antares f/6.3 Focal Reducer for Schmidt-Cassegrain Telescopes is a low-price option for reducing the focal length of your Schmidt-Cassegrain telescope from f/10 to f/6.3. By using this site, you agree to our Terms of Use. Go behind the scenes with Celestrons product development team and learn more about our award-winning and patented innovations. 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. External Focusers for Schmidt-Cassegrain Telescopes 3.1 The Basics of SCT Threads 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. 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. But the diameter of the image circle decreases by a factor of 0.63 to about 24mm. 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. 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. 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. We reserve the right to verify a competitor's advertised price and the availability of the item. The Reducer/Corrector can also be used for terrestrial digiscoping. 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! Your mileage may vary. 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. 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. Shipping will be via the cheapest shipping method which will vary depending on the items in your order. Details: The item must be the identical item, brand name, size, weight, color, quantity and model number. 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. 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. Opticstar F6.3 Focal Reducer / Corrector. The faster f/ratio allows you to use slower film or shoot in lower light level situations and still properly expose your subject. Celestrons patented StarSense Technology makes it easier than ever to locate objects in the night sky, even if youve never used a telescope before. Sign up for OPT news, exclusive offers, and updates on the latest gear! The equations in the Appendix show how this all works. Unlike . Sharpness is essentially the same. I wonder whether, for example, Antares focal reducer for SCT belongs to the latter category. For visual use, this means you get lower power with the same eyepiece and a wider field of view. Manish Panjwani has been an active amateur astronomer since before Halley's Comet last flew by our neighborhood. I was referring to the C6 to answer you specifically. Just one question. 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 Buyer's Guide To Eyepieces at the top of the Eyepieces forum has a column for this spec. Your wishlist has been temporarily saved. Yellow and orange members of open clusters stood out a bit more as the various stars displayed their individuality. More about this below. An image of about 24mm across, approximately, allows an observer to use a 1.25" eyepiece with a maximal field stop. This focal reducer is made to attach to the rear cell of Schmidt-Cassegrain or Maksutov-Cassegrain telescopes. You attach the focal reducer to the rear port on a SCT and can keep it covered. As a result, the smaller tube may cut into the light cone and effectively reduce the working aperture of the telescope. 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. 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. 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. The reduction factor MR can also be written in terms of d2 as: When the focal reducer is placed at the working distance, D, that is when d2=D, then the reduction factor MR is equal to the design reduction factor MRD: Equations (6) and (7) imply these important considerations: Most manufacturers do not publish the focal length of their focal reducers, so it is not usually possible to calculate the working distance and design reduction factor. 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. Get ready for a night of astroimaging with your mount faster than previously thought possible with All-Star Polar Alignment. Never noticed any anomalies with this unit. Start here to find the perfect telescope for you! 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. Bear in mind you can't squeeze blood out of a turnip, i.e. However, manufacturers virtually never provide this specification. Optically, it consists of a four-element lens that is fully multi-coated for high contrast and resolution. 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? 2023 OPT Telescopes. Using one on such a scope would make demands on the eyepiece design and increase the exit pupil to an extent that focal reduction on fast Newts is not practical. Looking forward to the day when I can do a shoot-out between a Japan and China Celestron, just for kicks. 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. Focal reducers also move the effective focal plane of the objective inward, that is, towards the objective (see Figure 1). 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. Most Feather Touch focusers cost between $300-$350. I only have the Celestron f/6.3. Take control of your telescope! You can adjust your cookie settings, otherwise we'll assume you're okay to continue. 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. 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. 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. 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. 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. These 0.63x focal reducers were originally designed to optimize for an image circle to match 36mm x 24mm film or its digital equivalent for astrophotography. . If the reducer is placed elsewhere, at a position called the operating distance, the focal reduction factor will not be as advertised. This is very impressive performance given how hard this problem is to mitigate in general. They are also less expensive than many external focusers of similar build quality. Some refractors such the TeleVue Nagler-Petzval (NP), the Takahashi "FSQ", and the William Optics Redcat/WhiteCat 51 have inherently flat fields because of internal optical elements. Despite never removing it no matter what I was looking at. 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. Reducer Lens .7x - EdgeHD 800 Learn More. The Antares is supposed to be pretty comparable. 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. Equation 6 & 7 item two & three does not make sense, both say increase its reduction (one should say reduce its reduction?). However, it will not thread into William Optics accessories, and with GSO it is a hit or miss. Your eyepieces are the first accessories you should learn to use with your telescope. It also leads to larger (although fainter) images of extended objects like the Moon or planets for astrophotographers or visual observers. Does anyone have any experience with the Celestron and Antares focal reducers? This article explains the basics of how focal reducers work with an astronomy telescope. There may have been an almost imperceptible difference, but the Antares and Celestron were producing precisely the same reduction. 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. 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 small animals were harmed in making these observations. Please let us know what topics you are interested in. This telescope control software replaces the hand control and allows the user to remotely control their Celestron computerized telescope from their personal PC or laptop. 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. looks virtually identical, except for the lettering. 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. When the camera sensor is placed at this distance, the reduction factor of these reducers is 0.75x. This means that there must be sufficient travel on the telescope focuser to make up for this. I had a Celestron, Antares and Hirsch for awhile and compared them over about a year. Description. There will be no shipments on 3/1/2023, 3/2/2023, or 3/3/2023 (March 1st - March 3rd, 2023). It works fine but you should stick with 1.25 EPs; or can use 2" EPs without corrector. The nominal design reduction factor of these reducers is typically 0.5x. ED glass is specially formulated and contains rare-earth compounds that greatly reduce a visual defect called chromatic aberration. We will match any online price that we confirm as valid. because they really dont matter. 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. These scopes are compatibles with focal reducers. Housings, threads, reduction, correction, blah, blah, blah. Once focused it's pretty good. So Celestron buyers like Celestron, Meade buyers like the Meade and Antares buyer like the Antares. Normal shipments will resume on Monday, March 6, 2023. nleash the full pointing accuracy of your Celestron computerized telescope with a specialized telescope control software suite. 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). The Celestron f/6.3 is ~150 compared to the Antares at ~70. They are commonly available in 1.25" and 2" threaded cells that conveniently thread into the nosepiece of a compatible camera or the barrel of an eyepiece. This was most noticeable on the eyepiece end of the RC, where the metal rim surrounding the lens was about 1mm thicker than on the Celestron. The naming convention of SCT focal reducers is a little confusing. Orders placed over the weekend will be shipped on the following Monday. That said any comparison reviews are helpful. if the illuminated field is 27mm wide without the reducer, it will be 27 x 0.63 = 17mm with it in place. Designed distancing using the reducer with a 1.25 visual back and 1.25 Televue mirror diagonal; Since the Celestron and Antares are supposed to have different focal lengths and spacing specs, I expected different results. This "speeds up" the optical train by reducing the focal length and magnification of the scope, requiring less time to integrate the same signal. Some third-party vendors also make reducers for SCT scopes. Never used one, but read the reviews here that suggest a coating problem. The two samples I have PERFORM IDENTICALLY. 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. In your opinion, is the Celestron is worth the added cost ($150 vs. $90)? . Wonder how they would stack up with a Japanese 6.3. Copyright 2003-2022 Agena AstroProducts. Well done. Please note, orders placed after 10am on 2/28/2023 will be delayed. Since then, Agena has become one of the leading online retailers of telescopes and astronomical accessories worldwide. The C8 has no noticeable vignetting with a 32mm Plssl in the f/6.3 reducer. However, the export of some items may be restricted outside the US due to size or manufacturer restrictions. This appendix summarizes how this works based on simple equations from the book Telescope Optics by Rutten and van Venrooij. - thanks. 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. 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. Dedicated focal reducers for refractors are intended primarily for imaging, not visual observation. 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: 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. They only publish the value of D, the working distance (sometimes called the back focus distance) and the design reduction factor MRD. Rather than a direct side-by-side, I swapped the reducers so that I was using them on the exact same, well-collimated instrument. High power views will provide flatter fields all the way to the edge, both visually and photographically. Powered by Invision Community. Focal reducers for these relatively fast ED refractors are generally for imaging only, not for visual observation. Regardless, the difference was miniscule and is more than adequate on both and exceeds a 8 or 6 SCTs baffle tube diameter. More aggressive reduction, or using these reducers with larger sensors, will result in aberrations and distortions near the edge of the image. 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. We have corrected # (iii) after equations 6 & 7. It has only one cover, which surprised me. In practice, it's important to remember that you will rarely operate at the exact working distance and at the exact reduction factor that is specified. All additional accessories mount onto the exterior/male threads. I am a purely visual observer, so will evaluate for visual use only. And, the reality is that every F/6.3 RC out there Celestron, Hirsch, Astromania, etc., etc. For example, an 8" SCT without a focal reducer has an illuminated field of 38mm at 50% fall-off. The key points are as follows: So just remember that a smaller distance (from the camera or eyepiece) means a lower amount of reduction (and vice versa). 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. 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. The telescope side of the barrel is often threaded with an M48 x 0.75 thread for standard 2" astronomy filters. 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. If you are using a camera that has a back focus of less than 55mm, additional spacer rings will be required between the reducer and the camera.