antares vs celestron focal reducer
Refractors, or SCTs with external focusers, may not have sufficient in-travel to reach focus in some configurations. It was also a little brighter in the center of the field with subtle darkening in the outer 20% or so. For example, an 8" SCT without a focal reducer has an illuminated field of 38mm at 50% fall-off. Your price: $579.00. 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. As another example,GSO makes focal reducers for their line of Ritchey-Chretien imaging telescopes. He also holds a Ph.D. in engineering physics from McMaster University. The lens that the ZWO comes with give a perfect wide angle image of what is in front of it. 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. * Not a Retail Store * 16313 Arthur StreetCerritos, CA 90703, USA, Availability: Item has been discontinued by Agena and we no longer carry this item. Unlike . Thanks guys, appreciate the feedback. 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. Focus misses by about 1 turnof the focus knob.Here is my solution:Buy a shorter 1.25 visual back for my scope. A former wireless communications consulting engineer and management consultant to various Fortune 500 companies, Manish started Agena AstroProducts in 2003. No small animals were harmed in making these observations. If I had to guess, the difference is maybe 10-15 grams. Please note, orders placed after 10am on 2/28/2023 will be delayed. I would not use the reducer with a 2" diagonal or eyepiece in the C6. Fumbling around in the dark, fine threads might be a problem. However, even though the imprint on the item states "Reducer / Corrector" please note that his is a reducer only. 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. 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. Rather than a direct side-by-side, I swapped the reducers so that I was using them on the exact same, well-collimated instrument. Sign up to get exclusive deals, observing tips, and new product announcements. Therefore, a 55mm back focus with a filter that is 3mm thick added to the imaging train would become 56mm. The stock Celestron visualback is just under 2 long. In many cases, the answer is yes, especially for electronically-assisted astronomy (EAA). This part is no longer in production, but it is sometimes available used and may be used with cameras with smaller sensors. It was used strictly for imaging, not visual observing. 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. Most focal reducers are designed to operate optimally at the working distance in the optical path to achieve their specified reduction factor, which is usually between 0.5x and 0.8x. The focus barely shifts between filters and I suspect any shifts I do get are down to the filters and changes in temp. 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. Not noticed any optical problems. Our proprietary StarBright XLT optical coatings dramatically increase transmission, up to 97.4% on our Schmidt corrector lenses. Who cares? Manish Panjwani has been an active amateur astronomer since before Halley's Comet last flew by our neighborhood. InternetSales@optcorp.com, 800-483-6287 There are also third-party vendors such as Hotech. Since the focal length of the reducer, FR, is fixed, as d2 increases then MR decreases. Another factor to consider: focal reducers also increase the angle at which light approaches the focal plane. 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. which looks like the same one. Reducer - Corrector Just one question. Reducer Lens .7x - EdgeHD 800 Learn More. 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 wonder whether, for example, Antares focal reducer for SCT belongs to the latter category. 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. 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. 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. Keep in mind that these differences were very subtle, and could be due to normal variations in coatings among different runs, and not necessarily unique to the brands. You currently have javascript disabled. Torazz The most significant mechanical variation, however, is the quality and precision of the threading. I think that the FRs made in Japan in the day may have been better. Style: 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. 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. At least these two units I tested make the answer - whatever. 2023 OPT Telescopes. Download the Celestron PWI Telescope Control Software. 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. The Celestron is both a corrector and focal reducer and the Antares is just a focal reducer. Turn it on and push Align. In about three minutes, youre ready to observe! Equation 6 & 7 item two & three does not make sense, both say increase its reduction (one should say reduce its reduction?). I have/had both the Celestron (Japan) and Antares units. For example, a 0.8x reducer placed at the working distance provides a reduction of (1 0.8) x 100 = 20%. If the reducer is placed elsewhere, at a position called the operating distance, the focal reduction factor will not be as advertised. I was referring to the C6 to answer you specifically. I have both the Antares and the Celestron reducers. How does it look thats what matters. The focal length of a focal reducer is usually measured from the rear lens surface of the reducer (and not the reducer's housing). The two samples I have PERFORM IDENTICALLY. Field stop diameters are one of the specified specs of eyepieces. I wont bother with differences in packaging, caps, etc. In your opinion, is the Celestron is worth the added cost ($150 vs. $90)? It can also be used with any other small chip CCD camera having a 1.25" nosepiece, such as the Celestron NexImage, Meade DSI . Antares Click Lock Visual Back - posted in Cats & Casses: Here is the situation:I bought a Celestron CPC 1100 for visual use.Want to put on the scope simulteanously a6.3 focal reducer, filter wheel, and aneyepiece turret. If used with other f/ratios, the field flattening characteristic may be unpredictable. Observing the microscopic world has never been easier! They never really recovered from selling a few 15 years back with element reversed. A reducer is a set of converging (or positive) lenses that cause the light from a telescope objective to converge at a steeper angle to the focal plane as if it were coming from an objective with a faster (lower) focal ratio and a shorter focal length. looks virtually identical, except for the lettering. A few large telescopes and mounts are excluded from this free shipping offer. 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. If you want to use them for visual - try maybe long focal length eyepieces rather than the reducer. I've heard and read all kinds of things about the Antares being only a reducer and not a corrector, etc. Thanks. The naming convention of SCT focal reducers is a little confusing. 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. As per the OP I still can't see any reason to buy the Celestron for significantly more $$$. Read our 101 article or get in touch. I've seen some older threads saying that the Celestron, Meade and Antares FRs are all the same and manufactured in the same factory. 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. The Antares is supposed to be pretty comparable. Focal reducers for these relatively fast ED refractors are generally for imaging only, not for visual observation. These reducers can also be used for visual observing with SCT scopes with eyepieces with a field stop as large as 24-27mm. 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. All rights reserved. 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. This also resulted in the clear aperture of the Antares being about 39-39.5mm, versus the Celestrons 41mm. This filter threads on to the rear cell of your Celestron or Meade SCT telescope. The reducer fits all Meade and Celestron . StevieDvd Members 1,182 1,812 Location: Stevenage, UK Posted March 9, 2021 (edited) Don't know but your welcome to try out my Meade 6.3 sct reducer next time you are passing. Start here to find the perfect telescope for you! A slight nod to the Antares for heft and higher transmission, but points to the Celestron for nice threads and better contrast. Wonder how they would stack up with a Japanese 6.3. Given the results of Test #1, I wanted to see if there was any truth to this assumption. Perhaps not exactly- there will be some uncertainty because of manufacturing tolerances and so forth, but it will be close. 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. We only send interesting emails and will never sell your data. Today, our world-class team of optical and electronic engineers continues to push the boundaries of technology. Melotte 15 - First Process in PixInsight (easy! Reducer Lens .7x - EdgeHD 800 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. It also leads to larger (although fainter) images of extended objects like the Moon or planets for astrophotographers or visual observers. The threads were similar on the eyepiece end, but a bit smoother. It features a standard male SCT thread (2" OD, 24 TPI) on one side and a standard SCT female thread on the other. Yellow and orange members of open clusters stood out a bit more as the various stars displayed their individuality. 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. The problem with those SCT reducers is that they cause chromatic aberration and require refocusing when using parfocal RGB/other filters. What I do know is that the Antares and the Celestron samples that I have perform exactly the same from the center right out to the edges. 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. Hello! If it's positioned further from the eyepiece or camera and closer to the telescope objective, the reduction factor increases. Regardless, the difference was miniscule and is more than adequate on both and exceeds a 8 or 6 SCTs baffle tube diameter. The visual back must be removed first. Most different was that the sky background was a little darker and more uniform, providing a tiny contrast boost for fainter objects. Will not focus with the stuff I have. 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. The Celestron f/6.3 is ~150 compared to the Antares at ~70. Reducer - Corrector Learn More. 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. Upon close inspection, it was clear that the housing of Antares assembled in Canada version was a little more substantial than the Celestron. 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. Despite never removing it no matter what I was looking at. riklaunim Members 559 3,445 Location: Poland Posted October 11, 2010 They are reported as identical. October 11, 2010 in Discussions - Scopes / Whole setups. 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. 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. 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. Reducer Lens .7x - EdgeHD 1400 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. This fully multi-coated lens provides maximum light transmission with near full-field illumination. High power views will provide flatter fields all the way to the edge, both visually and photographically. I use the same back spacing for both on a small 6" Celestron SCT. The Celestron f/6.3 is ~150 compared to the Antares at ~70. Edited by bluewater, 05 September 2020 - 11:27 AM. I have had the Japan unit on the back of my C5 since 1994 or thereabouts. Meade once made an f/3.3 focal reducer for SCT scopes. When the camera sensor is placed at this distance, the reduction factor of these reducers is 0.75x. I found both to be very good. I doubt there is any difference between the Antares and the Celestron except price. The telescope side of the barrel is often threaded with an M48 x 0.75 thread for standard 2" astronomy filters. Celestrons FREE planetarium app is an astronomy suite that redefines how you experience the night sky. Add a 0.63x reducer, and the brightness of extended objects increases by (1/0.63)2 = 2.5. 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. The Best Dedicated Astronomy Cameras for Beginners, Astronomik OIII 12nm CCD Filter - T-Threads, Pegasus Astro Dual Motor Focus Controller, 10 Micron 12kg (26.45lbs) Stainless Steel Counterweight- GM 2000, I would like more information regarding stock availability dates. But in the Japan version I have never noticed any anomaly like the ghosting in the China R/C. This focal reducer and field flattener consists of a four-element multicoated 40mm lens in a metal cell. 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. Powered by Invision Community. DUE TO EXTREMELY HIGH DEMAND, WE WILL NOT BE TAKING NEW ORDERS UNTIL MONDAY, DECEMBER 14. 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. I'd favor the Japanese Celestron version over the others that are commercially available. No retailers currently carry this product. 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). The distance d2, which measures the position of the new focal plane of the objective from the back of the focal reducer is given by Equation 5: In these equations, d1, d2, and MR are all variables that depend on each other through Equations 2 and 4. However, it will not thread into William Optics accessories, and with GSO it is a hit or miss. 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. Most reducers have a design reduction factor, MRD, that assumes the reducer is placed at a specific working distance, D, from the back surface of the focal reducer itself. To calculate how much back focus spacing you need to add, take the thickness of the filter and divide it by 3. 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. Celestron Focus Motor for SCT, EdgeHD & 8" RASA, Celestron C6 0.63 reducer/flattener back focus. Orders placed after 12:00 PM Pacific Time will be shipped the next business day. Stars in the corner of the image frame are indistinguishable between the Antares and the Celestron. 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. Specially-designed focal reducers are available for use with these telescopes. 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. Blue Fireball M42 T/T2 Thread Camera Adapter for Prime Focus Photography - 2" # P-06, Celestron T-Ring for Canon EOS Camera # 93419, GSO 2" Crayford Focuser for SCTs - Dual Speed, Length of male SCT thread = 5mm (0.2") but this is preceded by an unthreaded part on the eyepiece side making the total length = 8.8mm (0.35"), Length of female SCT thread = 7.5mm (0.3"). The internal surfaces are blackened and glare-threaded to provide the highest contrast. Maybe I got a lemon. 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. 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. Focal reducers for many SCTs and their flat-field equivalents usually have a back-focus distance of 105mm. 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. 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. The C8 has no noticeable vignetting with a 32mm Plssl in the f/6.3 reducer. 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. Sign up for OPT news, exclusive offers, and updates on the latest gear! A useful thing to know is how far from the objective lens (for a refractor) is the focal reducer located. Many Ritchey-Chretien telescopes available today are made by GSO. 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. Thanks for any advice or experience you could share. Request stock alerts and we'll let you know when the item is back in stock. A few people have reported issues with the male SCT thread diameter on this item being a bit larger than necessary. The focal length and design working distance for this focal reducer were not available from the manufacturer. Equation (4) shows the relationship between the distance d2 and the reduction factor MR. A longer effective focal length leads to higher magnification with a given eyepiece for visual observers. JavaScript seems to be disabled in your browser. Reducer Lens .7x - EdgeHD 925 Learn More. For me, I was looking for, and planning to keep, the one that yielded the greatest reduction. My application is mostly visual now, but I'm looking to do more astrophotography over time. Copyright 2021 Stargazers Lounge Focal reducers (and focal reducer/field flatteners combos) are usually used with two types of telescopes, refractors and compound telescopes such as Schmidt-Cassegrain or Ritchey-Chretien. It's usually specified in millimeters. It seems right to put some distance between the camera and the focal reducer, right? Never noticed any anomalies with this unit. 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. This "speeds up" the optical train by reducing the focal length and magnification of the scope, requiring less time to integrate the same signal. Start Chat Please re-enable javascript to access full functionality. Any comments gratefully received. Reducer Lens .7x - EdgeHD 1100 Learn More. 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. Orders placed over the weekend will be shipped on the following Monday. 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. An image of about 24mm across, approximately, allows an observer to use a 1.25" eyepiece with a maximal field stop. When using the diagonal, keep the field stops of the eyepieces under 20mm. The same illumination you have at the edge of a 27mm field, the C8 has at the edge of a 38mm field. Meade and Celestron both sell such SCT-T adapters with the correct optical length. 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. if the illuminated field is 27mm wide without the reducer, it will be 27 x 0.63 = 17mm with it in place. Thanks guys, I'm trying to get my ZWO ASI120MC-S to work with my 90mm Meade. Have a promo code? More about this below. Since then, Agena has become one of the leading online retailers of telescopes and astronomical accessories worldwide. You can probably eke out 1.2 without noticing serious vignetting, which is a field stop of 31.5mm. Hi. Your mileage may vary. ), but stars seemed a bit tighter and their colors were richer and more dramatic. a Tele Vue Panoptic), or a Plossl eyepiece with an apparent field of view of 50 and a focal length of 32mm. In some cases, focal reducers also act as field flatteners by correcting for field curvature and coma of the objective lens. Figure 2 shows the effective of a focal reducer on the light from a telescope objective. Read our guide! 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. In some cases, focal reducers also act as field flatteners by correcting for field curvature and coma of the objective lens. Nebula Filters. For example, the focal reducer for an 8-inch Celestron EdgeHD telescope has a design reduction factor of 0.7x and a specified working distance (or back focus) of 105mm. 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. But the diameter of the image circle decreases by a factor of 0.63 to about 24mm. Possibly the design of the Antares was changed .. Once installed, you can add additional accessories like T-Adapters, 1.25 Visual Back, Star Diagonal, or Off-Axis Guider. 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. 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. Sign up for a new account in our community. 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. More important, its clear that the Antares is a reducer/corrector, just like the Celestron and not merely a reducer. How about for visual observers? In such cases, we will be happy to take the item back as per our standard return terms. 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. Obviously bright objects like Jupiter or The Moon show the reflections. 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. Thanks for pointing this out. 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.