At least these two units I tested make the answer - whatever. Rather than a direct side-by-side, I swapped the reducers so that I was using them on the exact same, well-collimated instrument. For example, a 0.8x reducer placed at the working distance provides a reduction of (1 0.8) x 100 = 20%. Images in the Celestron tended to appear ever-so-slightly dimmer (maybe? 0.63x Starizona Focal Reducer for SCTs- Awesome Astrophotography However, even though the imprint on the item states "Reducer / Corrector" please note that his is a reducer only. However, the export of some items may be restricted outside the US due to size or manufacturer restrictions. Try & buy if you like - usual mates rates. 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. JavaScript seems to be disabled in your browser. This also resulted in the clear aperture of the Antares being about 39-39.5mm, versus the Celestrons 41mm. A few large telescopes and mounts are excluded from this free shipping offer. The Celestron f/6.3 is ~150 compared to the Antares at ~70. 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. But when not in the box or on the telescope, there is no cover for the other end. Best evidence would by obtained by using a camera and evaluating the image both by eye and with a computer analysis. Fumbling around in the dark, fine threads might be a problem. There is a way to make subjective data more useful and that way is proper blind, or better still. This is one of our best-selling items, and customers have reported that this product is at least as good as, and probably better than, other leading f/6.3 focal reducers sold on the market for a lot more. How does it look thats what matters. CPWI has an extensive object database, employs PointXP mount modeling, and more. Focus misses by about 1 turnof the focus knob.Here is my solution:Buy a shorter 1.25 visual back for my scope. Besides observing from his heavily light polluted backyard in Los Angeles, Manish enjoys conducting astronomy outreach programs in local schools. Field stop diameters are one of the specified specs of eyepieces. By 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. This focal reducer and field flattener consists of a four-element multicoated 40mm lens in a metal cell. Michael 1 ronin Members This means that there must be sufficient travel on the telescope focuser to make up for this. In terms of reduction and correction which are what reducer/correctors are supposed to do both are superb. 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. 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. But the diameter of the image circle decreases by a factor of 0.63 to about 24mm. Focal reducer for 8SE - Celestron vs. Antares - Cloudy Nights 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. A useful thing to know is how far from the objective lens (for a refractor) is the focal reducer located. I wish there was. Several functions may not work. 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. . A few people have reported issues with the male SCT thread diameter on this item being a bit larger than necessary. Well done. But in the end they both do pretty much the same thing and it sounds like any performance difference is subtle. 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. 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. I have this one Opticstar F6.3 Focal Reducer / Corrector. Assuming you use the reducer with the stock 1.25" diagonal, it will operate at f/6.3. That includes, for example, a 1.25" eyepiece with an apparent field of view of 68 and a focal length of 24mm (eg. Place the plastic covers on the lens when not in use to reduce the dust collection. Completely stuck, completely frustrated. For the best experience on our site, be sure to turn on Javascript in your browser. Unique focal reducer and field corrector lens accessory Reduces the focal length and f/ ratio of your Schmidt-Cassegrain telescope by 37% Provides a dual focal ratio instrument, without sacrificing image quality Compatible with all Schmidt-Cassegrain telescopes (see compatible list in description) Share Customers Also Purchased Description 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. 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. I'd favor the Japanese Celestron version over the others that are commercially available. No results, please adjust your filters. Hello! 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. Focal Reducers - Complete Overview and Function - YouTube I have the Antares and have no complaints. 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. I have had the Japan unit on the back of my C5 since 1994 or thereabouts. 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. The C8 has no noticeable vignetting with a 32mm Plssl in the f/6.3 reducer. Antares or Celestron? The price for an item/offer must be listed and valid at the time of match. I use it on my C8 SCT with a 1000d, and it seems to do everything written on the tin. Equation 6 & 7 item two & three does not make sense, both say increase its reduction (one should say reduce its reduction?). Very helpful, thanks a lot for this article! All Rights Reserved. Manish Panjwani has been an active amateur astronomer since before Halley's Comet last flew by our neighborhood. InternetSales@optcorp.com, 800-483-6287 Copyright 2003-2022 Agena AstroProducts. 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. Celestron or Antares f/6.3 focal reducer for SCT? Stars in the corner of the image frame are indistinguishable between the Antares and the Celestron. which looks like the same one. Many focal reducers are meant to be used within a few millimeters of the specified working distance to achieve the best possible image results. They provide 0.75x focal reducers for these telescopes that takes an f/8 instrument down to f/6. 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? Specially-designed focal reducers are available for use with these telescopes. If the reducer is placed closer to the eyepiece or camera than the distance D, the reduction factor decreases. As a Barlow's magnification increases with increasing distance from the Barlow, a focal reducer's reduction increases with increasing distance from the reducer. They are designed (assuming you are referring to the f/6.3 version) for the f/10 light cone. Please let us know what topics you are interested in. 3. 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. Possibly the design of the Antares was changed .. * Not a Retail Store * 16313 Arthur StreetCerritos, CA 90703, USA. Back-Focus 101: DSLR Cameras & the Celestron f/6.3 Reducer - YouTube And, the reality is that every F/6.3 RC out there Celestron, Hirsch, Astromania, etc., etc. Thanks guys, I'm trying to get my ZWO ASI120MC-S to work with my 90mm Meade. Agena's Guide to Focal Reducers - Agena Astro No negative issues to report. Hi. 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. Thanks for the extremely valuable article. Enter it during checkout! If used with other f/ratios, the field flattening characteristic may be unpredictable. Whereas the Celestron threaded smoothly onto the scope, the Antares chattered and squeaked a bit more so when being removed. Celestron makes a series of focal reducers for the Edge HD line that are matched to the 8", 9.25", 11", and 14" apertures of these scopes. 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. Thanks. The visual back must be removed first. For this shoot-out, I used a standard Celestron C8 with Starbright coatings. Reducer - Corrector | Celestron On the trail, at the job site, in the classroom, or simply sitting at home relaxing the Celestron Elements ThermoTank 3 will keep your hands toasty. Product Details. Celestron Solar Safe filter technology is GUARANTEED SAFE for direct solar observation and has been independently tested by SAI Global Assurance Services. It's an either/or proposition: reducer and 1.25", or 2", but not 2" and reducer. In most cases, the easiest option is to choose the focal reducer made specifically for your telescope. 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. Contiguous US Customers:All items we sell ship for free within the Contiguous US. These RC reducers cannot be used with other types of telescopes. Shipping will be via the cheapest shipping method which will vary depending on the items in your order. The female end attaches to the rear cell of the telescope. control and Sky Viewer display makes selecting your target easy. 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. There are also third-party vendors such as Hotech. You need to be a member in order to leave a comment. First, I wanted to compare the actual reduction provided by these competitors, as many threads here cite different ideal spacing from the reducer to eyepiece focal plane to achieve the correct f/6.3 result. 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. Antares f/6.3 Focal Reducer for SCTs - Awesome Astro I've looked through one from Meade and first impression was that it was like the Celestron version. But is there a difference in quality between the Antares and the Celestron or Meade focal reducers? In many cases, the answer is yes, especially for electronically-assisted astronomy (EAA). Will not focus with the stuff I have. Quite interestingly it bears the very same engravings of the Meade 4000 r/c (including "series 4000") except for "MEADE". And when used in some refractors, the field flattening is not as accurate as it is in the f/10 SCTs. The telescope side of the barrel is often threaded with an M48 x 0.75 thread for standard 2" astronomy filters. 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. 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. As a result, the smaller tube may cut into the light cone and effectively reduce the working aperture of the telescope. Steve CEL-94245. I'm going with the Celestron. Like many of us with SCTs, I have bought and sold a number of f/6.3 reducer/correctors over the years, and I have always been curious how they really stack up to each other. Can these economical focal reducers from GSO and other vendors result in good images? Orders placed after 12:00 PM Pacific Time will be shipped the next business day. Dedicated focal reducers for refractors are intended primarily for imaging, not visual observation. Obviously bright objects like Jupiter or The Moon show the reflections. However, these will not impact optical performance. Thanks Peter! I've heard and read all kinds of things about the Antares being only a reducer and not a corrector, etc. No small animals were harmed in making these observations. In this case, an additional T-adapter (with an optical length of 50mm) is needed to get the spacing correct for a DSLR or other camera with a 55mm back focus. Using an eyepiece with a 27mm field stop with the reducer will illuminate the edge the same as using an eyepieces with a 42.9mm field stop without it. For imagers, the main purpose of a focal reducer is to increase the brightness of the image at the focal plane. Brian Ventrudo is a writer, scientist, and astronomy educator. When the camera sensor is placed at this distance, the reduction factor of these reducers is 0.75x. I only have the Celestron f/6.3. You attach the focal reducer to the rear port on a SCT and can keep it covered. A former wireless communications consulting engineer and management consultant to various Fortune 500 companies, Manish started Agena AstroProducts in 2003. Your mileage may vary. 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. The two samples I have PERFORM IDENTICALLY. You don't need to follow these equations to use a focal reducer, but they do show how the reduction factor changes with the placement of the reducer. Thanks for pointing this out. I was referring to the C6 to answer you specifically. 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. For me the Antares was a little brighter and had the least scatter by a bit so the better coatings won. Fortunately, my neighbors are not out in their backyards at 11 pm, or they may have thought I was torturing a small mammal. 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. Celestron or Antares f/6.3 focal reducer for SCT? DUE TO EXTREMELY HIGH DEMAND, WE WILL NOT BE TAKING NEW ORDERS UNTIL MONDAY, DECEMBER 14. They only publish the value of D, the working distance (sometimes called the back focus distance) and the design reduction factor MRD. Nowadays I tend to use the Celestron more with my refractors for imaging and viewing. 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. The brightness, shape, and distortion of specific stars in the exact same position at the edge of the field was precisely identical in both reducers. I've seen some older threads saying that the Celestron, Meade and Antares FRs are all the same and manufactured in the same factory. If you want to use them for visual - try maybe long focal length eyepieces rather than the reducer. You currently have javascript disabled. Optically, it consists of a four-element lens that is fully multi-coated for high contrast and resolution. More aggressive reduction, or using these reducers with larger sensors, will result in aberrations and distortions near the edge of the image. We will be glad to help. A focal reducer does just the opposite of a Barlow lens or focal extender. 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. No rainchecks will be issued for items out of stock at OPTcorp.com to match a competitor's price. So, if you have a filter that is 3mm thick, you need to add 1mm of spacing to your imaging train to retain the correct back focus. With the Celestron Reducer/Corrector Lens, thats precisely what you get. The amount of reduction is simply the percentage by which a reducer shortens the effective focal length of a telescope and is calculated as (1 Reduction Factor) x 100%.