The Antares f6.3 focal reducer screws directly to the visual-back thread of all popular SCTs and converts f10 instruments to f6.3. Upgrading the Focuser of Your Schmidt-Cassegrain Telescope - Agena Astro 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). Nada. Reducer Lens .7x - EdgeHD 800 Learn More. What an enjoyable read and detailed comparison. But in the end they both do pretty much the same thing and it sounds like any performance difference is subtle. We will be glad to help. All additional accessories mount onto the exterior/male 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. Reducer Lens .7x - EdgeHD 1400 The more focal reduction, the further inward the focal plane will be. Focal Reducer, 2", 0.7X. Thks for that and its not for visual it for astrophotography. 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. However, even though the imprint on the item states "Reducer / Corrector" please note that his is a reducer only. This article explains the basics of how focal reducers work with an astronomy telescope. This would tell us exactly how well aberrations are corrected. 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. However, it will not thread into William Optics accessories, and with GSO it is a hit or miss. Looking forward to the day when I can do a shoot-out between a Japan and China Celestron, just for kicks. Figure 2 shows the effective of a focal reducer on the light from a telescope objective. 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. 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. Please re-enable javascript to access full functionality. For the best experience on our site, be sure to turn on Javascript in your browser. More details are found in the Appendix of this article. How about for visual observers? In every configuration, there were essentially parfocal, requiring only a tiny fine focus adjustment when changing correctors. The visual back must be removed first. Obviously bright objects like Jupiter or The Moon show the reflections. Most Feather Touch focusers cost between $300-$350. Again, to my surprise, there was absolutely no difference between the Celestron and Antares on any star. But I am rusty, can you condense a bit for me please? 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 think I remember hearing the reduction factor is slightly different, cant remember more or less reduction. Celestron or Antares? The new Lithium Phosphate (LiFePO4) battery chemistry has significant advantages over other battery chemistries, great for for those Astronomers on the go. At a significantly lower price point, the Antares is a steal, and theres no need to upgrade to the Celestron if you already have one. These 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. Just one question. This fully multi-coated lens provides maximum light transmission with near full-field illumination. . WiFi technology encircles the globe in a web of connectivity, knowledge, and information. It's highly unlikely that they could be so precisely identical unless they were. He tested this on an 8 Celestron , I have a Celestron 6SE. The Reducer/Corrector is easy to install by threading the unit onto the rear cell of your Schmidt-Cassegrain telescope (or the reducer plate of the C11 and C14). Very helpful, thanks a lot for this article! A few large telescopes and mounts are excluded from this free shipping offer. The stock Celestron visualback is just under 2 long. This also resulted in the clear aperture of the Antares being about 39-39.5mm, versus the Celestrons 41mm. Style: 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. This focal reducer and field flattener consists of a four-element multicoated 40mm lens in a metal cell. Perfect for the serious student, professional scientist and discriminating hobbyist. Contiguous US Customers:All items we sell ship for free within the Contiguous US. Fumbling around in the dark, fine threads might be a problem. Focus misses by about 1 turnof the focus knob.Here is my solution:Buy a shorter 1.25 visual back for my scope. For imagers, the main purpose of a focal reducer is to increase the brightness of the image at the focal plane. One of the most important factors in a telescope is its transmissionthe percentage of light that reaches the focal plane. 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. Celestrons aplanatic EdgeHD optics revolutionized astroimaging. 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). 0.5X focal reducer for Celestron, Meade, and Orion CCD imaging cameras This is a. Such an image circle is still large enough to encompass the relatively large sensor of many deep-sky astronomy cameras. And when d1 = FR, that is, when the focal reducer is placed at a distance from the focal plane of the objective that's equal to the reducer's focal length, the focal length of the combined optical system is Fo, so it acts as a 0.5x reducer. I have/had both the Celestron (Japan) and Antares units. 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. 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. Our proprietary StarBright XLT optical coatings dramatically increase transmission, up to 97.4% on our Schmidt corrector lenses. 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. When using the diagonal, keep the field stops of the eyepieces under 20mm. I have both the Antares and the Celestron reducers. Place the plastic covers on the lens when not in use to reduce the dust collection. Does anyone know if the Antares 4000 focal reducer is as good as the Celestron focal reducer. I have Hirsch focal reducer, which is yet another clone of the Celestron reducer. There will be no shipments on 3/1/2023, 3/2/2023, or 3/3/2023 (March 1st - March 3rd, 2023). And, the reality is that every F/6.3 RC out there Celestron, Hirsch, Astromania, etc., etc. However, this also came at a cost, as the sky background in the Antares was slightly brighter. The resultant reduction factor was measured to be 0.46x. 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. 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. Learn more about extra solar planets imagery, 3D Star rendering, observation planning, telescope control, multiple-panel printing, and much more. Thanks for the extremely valuable article. 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. I only have the Celestron f/6.3. Have always disliked the crude, noisy SCT threads, but I get it. A f/10 focal ratio now achieves a f/6.3, while an f/11 focal ratio now achieves a f/7. Reproduction without permission prohibited. 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. 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. For example, a 0.8x reducer placed at the working distance provides a reduction of (1 0.8) x 100 = 20%. They are also less expensive than many external focusers of similar build quality. 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. Turn it on and push Align. In about three minutes, youre ready to observe! Reducer - Corrector In some cases, focal reducers also act as field flatteners by correcting for field curvature and coma of the objective lens. Also read the reviews here, including those at 4 stars. The EdgeHD .7x Focal Reducer Lens makes your EdgeHD 1100 one full F-Stop faster than f/10, reducing your exposure time by half to capture the same brightness of object . 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. Focal Reducer for SCT - ACF - Stargazers Lounge 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'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 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. Also, the focusers of most Newtonians do not have enough in-travel to accommodate a focal reducer. An eyepiece with a 27mm field stop yields a true field of 1.03 in the C6 at f/10. Who cares? 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). Stars in the corner of the image frame are indistinguishable between the Antares and the Celestron. Celestron Focus Motor for SCT, EdgeHD & 8" RASA, Celestron C6 0.63 reducer/flattener back focus. For the best experience on our site, be sure to turn on Javascript in your browser. Several functions may not work. They provide 0.75x focal reducers for these telescopes that takes an f/8 instrument down to f/6. Equation (4) shows the relationship between the distance d2 and the reduction factor MR. Designed distancing using the reducer with a 1.25 visual back and 1.25 Televue mirror diagonal; Optically, it consists of a four-element lens that is fully multi-coated for high contrast and resolution. Explicitly designed for Celestron Schmidt-Cassegrain telescopes, this unique lens reduces your telescopes focal length and f/ ratio by 37%, turning your long focal length telescope into a fast, short focal length instrument. 2. The Buyer's Guide To Eyepieces at the top of the Eyepieces forum has a column for this spec. Sharpness is essentially the same. I think that the FRs made in Japan in the day may have been better. Edited by Tony Bonanno, 16 April 2021 - 06:44 PM. I have had the Japan unit on the back of my C5 since 1994 or thereabouts. These reducers have a back focus (or design working distance) of 80mm. The stars at the edge could be worse or better. Planetarium software package which provides easy-to-understand explanations and impressive visuals of all kinds. We do not price match competitors if they are out of stock. Sign up to get exclusive deals, observing tips, and new product announcements. With both, using the same diagonal set-up, the exact same stars were visible at the very edge of the FOV. It works fine but you should stick with 1.25 EPs; or can use 2" EPs without corrector. Please note, orders placed after 10am on 2/28/2023 will be delayed. looks virtually identical, except for the lettering. a Tele Vue Panoptic), or a Plossl eyepiece with an apparent field of view of 50 and a focal length of 32mm. October 11, 2010 in Discussions - Scopes / Whole setups. Orders placed over the weekend will be shipped on the following Monday. There is one difference though the Antares came with only one lens cap whereas the Celestron had a cap for both ends. With the barrel 1.25 reducer won't focus, all I get is fuzzy snowballs. Celestron's EdgeHD reducers feature a custom 5 element optical design engineered to maintain the flat-field performance of our award-winning EdgeHD optical system. Thanks guys, I'm trying to get my ZWO ASI120MC-S to work with my 90mm Meade. 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. Manish holds a Master's degree in Electrical Engineering from Virginia Tech and an MBA from the Kellogg School of Management at Northwestern University. A couple of tiny dust particles between lens elements, uneven lens edge blackening, very minor coating blemishes, or even a very small fine lens scratch or two are very common in this Antares product and must be accepted as normal for this item. They are designed (assuming you are referring to the f/6.3 version) for the f/10 light cone. 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. 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. control and Sky Viewer display makes selecting your target easy. If the reducer is placed closer to the eyepiece or camera than the distance D, the reduction factor decreases. It covers the basic optics and design specifications of a focal reducer, and goes through some practical factors to consider when selecting and using a focal reducer. Focal Reducer, 2", 0.7X - Antares 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. 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. 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. Since then, Agena has become one of the leading online retailers of telescopes and astronomical accessories worldwide. As another example,GSO makes focal reducers for their line of Ritchey-Chretien imaging telescopes. Best evidence would by obtained by using a camera and evaluating the image both by eye and with a computer analysis. 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. Practical Considerations of Focal Reducers, 4.2 Back Focus Requirements of Focal Reducers, GSO makes focal reducers for their line of Ritchey-Chretien, Celestron makes a series of focal reducers for the Edge HD line, 0.75x focal reducers for these telescopes, focal reducer for an 8-inch Celestron EdgeHD, A Primer on T-Rings and T-Adapters for Astronomy and Astrophotography, Choosing the Best Telescope for Beginners 2023, Top Night Sky & Astronomy Events in August 2022, Top Night Sky & Astronomy Events in July 2022, Selecting a Baader Planetarium Star Diagonal, A Guide to Choosing Astronomy Eyepieces for Binoviewers, Choosing a Magnifying Finder Scope for Your Telescope, A focal reducer will provide its design reduction factor only when it is placed at the exact working distance from the focal plane of the eyepiece or camera, Reducing the operating distance, that is, moving a focal reducer closer to the eyepiece or camera increases its reduction factor, or conversely reduces the amount of focal reduction. Meade once made an f/3.3 focal reducer for SCT scopes. I wish there was. 3. Dedicated focal reducers for refractors are intended primarily for imaging, not visual observation. Well done. I've seen some older threads saying that the Celestron, Meade and Antares FRs are all the same and manufactured in the same factory. Your eyepieces are the first accessories you should learn to use with your telescope. Unlike SCT telescopes, Ritchey-Chretien telescopes and Celestron Edge HD or Meade ACF scopes have internal optics that provide an inherently flat field, so these telescopes require a special focal reducer than does not provide additional correction for field curvature. Better images are also obtained when using these focal reducers at a reduction factor of 0.5x 0.8x, approximately. Imaging - Focal Reducers and Flatteners - Page 1 - KW Telescope I happily cycle through LRGB filters to build the image rather than do a whole run of one filter at a time. I have the Antares and have no complaints. For this shoot-out, I used a standard Celestron C8 with Starbright coatings. Thanks Peter! Getting the proper back-focus for your imaging camera is a vital step in getting the best data possible out of your telescope imaging/research rig. 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. Hello! No idea what the issue is. All rights reserved. JavaScript seems to be disabled in your browser. More aggressive reduction, or using these reducers with larger sensors, will result in aberrations and distortions near the edge of the image. Antares F/6.3 SCT Focal Reducer | OPT Telescopes I must admit, as well, that I no longer place a lot of stock in the notion that Chinese optics are inferior to Japanese or Taiwanese any longer, as manufacturing technology has really leveled the playing field today, with most Chinese optics being excellent. However, doesn't fit in the telescope and even if it did wouldn't work. 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. Thanks for any advice or experience you could share. Yellow and orange members of open clusters stood out a bit more as the various stars displayed their individuality. Get ready for a night of astroimaging with your mount faster than previously thought possible with All-Star Polar Alignment. There are many different types of focal reducers and they all effect. Explore Scientific - Keys to the Universe Sale. which looks like the same one. Performance wise what differences might there be using the reducer on a smaller scope. Shipping will be via the cheapest shipping method which will vary depending on the items in your order. He also holds a Ph.D. in engineering physics from McMaster University. 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. 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. Add a 0.63x reducer, and the brightness of extended objects increases by (1/0.63)2 = 2.5. 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. So it provides a 0.63x design reduction factor when used with an f/10 SCT at the specified working distance. 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. Celestrons FREE planetarium app is an astronomy suite that redefines how you experience the night sky.