A few people have reported issues with the male SCT thread diameter on this item being a bit larger than necessary. 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. 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. 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. Maybe I got a lemon. For imagers, the main purpose of a focal reducer is to increase the brightness of the image at the focal plane. The reducer is we might presume designed to correct to some as yet un-measured extent, the image of a standard SCT. 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. Easy solution found a very tiny dab of super lube on the threads and all was well and quiet.. 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. Despite never removing it no matter what I was looking at. A f/10 focal ratio now achieves a f/6.3, while an f/11 focal ratio now achieves a f/7. 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. No small animals were harmed in making these observations. It is recommended for . 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. 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. Whereas the Celestron threaded smoothly onto the scope, the Antares chattered and squeaked a bit more so when being removed. Fumbling around in the dark, fine threads might be a problem. They are also less expensive than many external focusers of similar build quality. * Not a Retail Store * 16313 Arthur StreetCerritos, CA 90703, USA. Details: The item must be the identical item, brand name, size, weight, color, quantity and model number. 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. Figure 6 shows a 1.25" focal reducer from GSO configured with a ZWO ASI224MC camera. But is there a difference in quality between the Antares and the Celestron or Meade focal reducers? I have a made in Japan 6.3 R/C and a made in China 6.3 R/C. 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). 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. We only send interesting emails and will never sell your data. For the best experience on our site, be sure to turn on Javascript in your browser. 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. Reducer Lens .7x - EdgeHD 1400 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. Torazz This also resulted in the clear aperture of the Antares being about 39-39.5mm, versus the Celestrons 41mm. What is likely is that fatigue sets in, and also that as the targets move toward or a way from the meridian there will be changes for that reason alone. Is that distance D= Fo-d1=Fo-(d2/MR)? 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. Optically, it consists of a four-element lens that is fully multi-coated for high contrast and resolution. The two samples I have PERFORM IDENTICALLY. 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. Most manufacturers provide this specification. I even lost track of which reducer I was using. The Reducer/Corrector can also be used for terrestrial digiscoping. It's usually specified from the base of the mounting threads on the reducer's housing, and this is the most practical way of providing this specification. 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 reducers have a back focus (or design working distance) of 80mm. We will be glad to help. October 11, 2010 in Discussions - Scopes / Whole setups. Not a bit. The focus barely shifts between filters and I suspect any shifts I do get are down to the filters and changes in temp. 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. All rights reserved. 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. Nebula Filters. More details are found in the Appendix of this article. I only have the Celestron f/6.3. Reducer Lens .7x - EdgeHD 800 Learn More. For the best experience on our site, be sure to turn on Javascript in your browser. They usually have a 2" barrel that slides into the telescope focuser. For visual use, this means you get lower power with the same eyepiece and a wider field of view. More aggressive reduction, or using these reducers with larger sensors, will result in aberrations and distortions near the edge of the image. Today, our world-class team of optical and electronic engineers continues to push the boundaries of technology. 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. Rather than a direct side-by-side, I swapped the reducers so that I was using them on the exact same, well-collimated instrument. 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. Again, to my surprise, there was absolutely no difference between the Celestron and Antares on any star. It's highly unlikely that they could be so precisely identical unless they were. There are many different types of focal reducers and they all effect. Dedicated focal reducers for refractors are intended primarily for imaging, not visual observation. I've never found my 0.63 reducer causing CA when used with my SCT. 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. 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. Thanks. 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. 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. You attach the focal reducer to the rear port on a SCT and can keep it covered. looks virtually identical, except for the lettering. This article explains the basics of how focal reducers work with an astronomy telescope. 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. 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. The most popular accessories for your new 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. 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. Our patented SkyAlign alignment technology makes setting up a computerized telescope simple, fast, and accurate. However, the export of some items may be restricted outside the US due to size or manufacturer restrictions. Some third-party vendors also make reducers for SCT scopes. With spring galaxy season here, I decided to pick up a couple more to compare in a head-to-head shoot out. One of the most important factors in a telescope is its transmissionthe percentage of light that reaches the focal plane. This standard distance is a consequence of the design of DSLR cameras for which the distance of the sensor to the outer edge of the flanges is about 45 mm, while the T-ring that attaches to the flange for astrophotography is about 10mm thick. 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. * Not a Retail Store * 16313 Arthur StreetCerritos, CA 90703, USA, Availability: Item has been discontinued by Agena and we no longer carry this item. Focal reducers for many SCTs and their flat-field equivalents usually have a back-focus distance of 105mm. Sign up for a new account in our community. ED glass is specially formulated and contains rare-earth compounds that greatly reduce a visual defect called chromatic aberration. I own both and concur heartily. The lens has a knurled surface, providing a tremendous gripping surface for threading/unthreading. Fortunately, my neighbors are not out in their backyards at 11 pm, or they may have thought I was torturing a small mammal. If I had to guess, the difference is maybe 10-15 grams. Read our 101 article or get in touch. This part is no longer in production, but it is sometimes available used and may be used with cameras with smaller sensors. 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. I have/had both the Celestron (Japan) and Antares units. 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. Advanced designs for Schmidt-Cassegrain scopes such as the Meade ACF or Celestron Edge HD have optical elements in the tube to correct for coma and field flatness. I'm going with the Celestron. However, doesn't fit in the telescope and even if it did wouldn't work. I was referring to the C6 to answer you specifically. By using this site, you agree to our Terms of Use. 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. The Celestron f/6.3 is ~150 compared to the Antares at ~70. However, these will not impact optical performance. The resultant reduction factor was measured to be 0.46x. This factor is designated by a power that is less than 1, and it usually lies between 0.5x or 0.8x. 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. Planetarium software package which provides easy-to-understand explanations and impressive visuals of all kinds. Reducer - Corrector Learn More. Sign up for our newsletter to get exclusive deals, observing tips, and new product announcements. However, even though the imprint on the item states "Reducer / Corrector" please note that his is a reducer only. Celestron Solar Safe filter technology is GUARANTEED SAFE for direct solar observation and has been independently tested by SAI Global Assurance Services. Powered by Invision Community. Our proprietary StarBright XLT optical coatings dramatically increase transmission, up to 97.4% on our Schmidt corrector lenses. a Tele Vue Panoptic), or a Plossl eyepiece with an apparent field of view of 50 and a focal length of 32mm. All rights reserved. Most amateur astronomers are familiar with a Barlow lens (or a focal extender), a negative or diverging lens that effectively increases the focal length and the focal ratio of a telescope's objective lens. Turn it on and push Align. In about three minutes, youre ready to observe! 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). Learn more about extra solar planets imagery, 3D Star rendering, observation planning, telescope control, multiple-panel printing, and much more. The Buyer's Guide To Eyepieces at the top of the Eyepieces forum has a column for this spec. 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. Copyright 2003-2022 Agena AstroProducts. So ab6110 is asking for a FR only without coma correction, there are a couple of brands who make special reducers for the ACF. Since then, Agena has become one of the leading online retailers of telescopes and astronomical accessories worldwide. ), 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. Is there likely to be any differences in performance between using these on an 8 or something smaller like my 6SE? Some faster refractors with a focal ratio of f/6, for example, only require field flatteners and not focal reducers. Melotte 15 - First Process in PixInsight (easy! The review is a subjective visual impression, which is interesting but not best evidence. Edited by bluewater, 05 September 2020 - 11:27 AM. In terms of reduction and correction which are what reducer/correctors are supposed to do both are superb. No difference. which looks like the same one. Edited by Tony Bonanno, 16 April 2021 - 06:44 PM. An f/6.3 reducer is designed to reduce the focal ratio of an f/10 SCT to f/6.3. 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. It features a standard male SCT thread (2" OD, 24 TPI) on one side and a standard SCT female thread on the other. Unlike . 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. Stock focusers in an SCT move the mirror of the scope to change the position of the focal plane, and they have sufficient travel to accommodate a focal reducer. 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. Focal reducers for these relatively fast ED refractors are generally for imaging only, not for visual observation. Hello! I was originally hoping to do this with a made in Japan Celestron, but ended up with a newer China version but thats probably better in the end since it is the version now available, with the Japan ones rarer and only available used. And, the reality is that every F/6.3 RC out there Celestron, Hirsch, Astromania, etc., etc. I've seen some older threads saying that the Celestron, Meade and Antares FRs are all the same and manufactured in the same factory. Equation 6 & 7 item two & three does not make sense, both say increase its reduction (one should say reduce its reduction?). 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. Antares or Celestron? 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. These scopes are compatibles with focal reducers. Free shipping $189.95 You can probably eke out 1.2 without noticing serious vignetting, which is a field stop of 31.5mm. Images in the Celestron tended to appear ever-so-slightly dimmer (maybe? Perfect for the serious student, professional scientist and discriminating hobbyist. Request stock alerts and we'll let you know when the item is back in stock. That said any comparison reviews are helpful. 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. 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. 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. If you want to save a few buck watch the classifieds on CN. 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. Using these numbers in equation 4 in the Appendix, below, we can easily calculate that the focal length of this unit is approximately103mm (it will be 103mm plus the small amount by which the rear lens surface of the reducer is recessed beneath the reducer housing). I have both the Antares and the Celestron reducers. I use the same back spacing for both on a small 6" Celestron SCT. They are reported as identical. 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. 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. Opticstar F6.3 Focal Reducer / Corrector. The working distance of the GSO 0.5x focal reducer with 1.25" barrel and the GSO 0.5x focal reducer with 2" barrel is about 51mm to 53mm, approximately, from the middle of the metal cell that holds the lens. Can you help me? In your opinion, is the Celestron is worth the added cost ($150 vs. $90)? InternetSales@optcorp.com, 800-483-6287 As a result, the smaller tube may cut into the light cone and effectively reduce the working aperture of the telescope. 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? Description. A focal reducer does just the opposite of a Barlow lens or focal extender. For me the Antares was a little brighter and had the least scatter by a bit so the better coatings won. 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. The reducer features fully coated optics in an anodized aluminum filter ring with an ergonomic rubber grip. Reducer Lens .7x - EdgeHD 1400 Learn More. 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. But in the Japan version I have never noticed any anomaly like the ghosting in the China R/C. These reducers can also be used for visual observing with SCT scopes with eyepieces with a field stop as large as 24-27mm. 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. 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. Upon close inspection, it was clear that the housing of Antares assembled in Canada version was a little more substantial than the Celestron. Well done. Even though they may have been slightly dimmer, galaxies were a bit easier to tease out of the urban light soup I deal with. So it provides a 0.63x design reduction factor when used with an f/10 SCT at the specified working distance. In every configuration, there were essentially parfocal, requiring only a tiny fine focus adjustment when changing correctors. Thanks guys, I'm trying to get my ZWO ASI120MC-S to work with my 90mm Meade. 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 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). 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. First, let's have a look at some key optical parameters are needed to understand focal reducers. I've only used it a few times but it looks good to me. Not noticed any optical problems. Read our guide! But when not in the box or on the telescope, there is no cover for the other end. 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. 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. Since 2008, Brian has taught astronomy to tens of thousands of stargazers through his websites OneMinuteAstronomer.com and CosmicPursuits.com. Many focal reducers are meant to be used within a few millimeters of the specified working distance to achieve the best possible image results. It's an either/or proposition: reducer and 1.25", or 2", but not 2" and reducer. I read another thread in a different forum about F6.3 reducer correctors and one amateur posted an image about glue coming out of an astromania f6.3 reducer which he planned to return. You currently have javascript disabled. Just point the telescope at any three bright objectsstars, bright planets, or even the Moonand your telescope can orient itself with the night sky. 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. 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. control and Sky Viewer display makes selecting your target easy. Stars in the corner of the image frame are indistinguishable between the Antares and the Celestron. I doubt there is any difference between the Antares and the Celestron except price. Assuming you use the reducer with the stock 1.25" diagonal, it will operate at f/6.3.