Such an image circle is still large enough to encompass the relatively large sensor of many deep-sky astronomy cameras. Go behind the scenes with Celestrons product development team and learn more about our award-winning and patented innovations. They are reported as identical. As a consequence, the standard f/6.3 and f/3.3 focal reducers for SCT scopes do not work. 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. Whereas the Celestron threaded smoothly onto the scope, the Antares chattered and squeaked a bit more so when being removed. 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. 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. 3. As a Barlow's magnification increases with increasing distance from the Barlow, a focal reducer's reduction increases with increasing distance from the reducer. Celestron Focus Motor for SCT, EdgeHD & 8" RASA, Celestron C6 0.63 reducer/flattener back focus. At least these two units I tested make the answer - whatever. ED glass is specially formulated and contains rare-earth compounds that greatly reduce a visual defect called chromatic aberration. Article Agena AstroProducts, 2019. Years ago, I bought the Antares version, and moved over to the Celestron. I also used several eyepieces including the ES 24mm/68, 17.5mm and 12.5mm Morpheuses, and a 10.5mm Pentax XL. As another example,GSO makes focal reducers for their line of Ritchey-Chretien imaging telescopes. In many cases, the answer is yes, especially for electronically-assisted astronomy (EAA). 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. An eyepiece with a 27mm field stop yields a true field of 1.03 in the C6 at f/10. As per the OP I still can't see any reason to buy the Celestron for significantly more $$$. A few large telescopes and mounts are excluded from this free shipping offer. Thanks guys, appreciate the feedback. As a result, the smaller tube may cut into the light cone and effectively reduce the working aperture of the telescope. 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. Your mileage may vary. They are also less expensive than many external focusers of similar build quality. 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. 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. A longer effective focal length leads to higher magnification with a given eyepiece for visual observers. That was fun. So it provides a 0.63x design reduction factor when used with an f/10 SCT at the specified working distance. I have a Raspberry HQ camera, a Sony TV Zoom 12.5-75mm f1.8 and a Astromania 1,25" 0.5x focal reducer. Style: Michael 1 ronin Members For the best experience on our site, be sure to turn on Javascript in your browser. 160K views 9 years ago This video is a complete overview of focal reducers and how they function applying to telescopes. 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. 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. Using this same example of an 8" SCT and a 0.63x reducer, a visual observer can also enjoy brighter images and a wider field of view. We will be glad to help. Shipping will be via the cheapest shipping method which will vary depending on the items in your order. The Reducer/Corrector can also be used for terrestrial digiscoping. It's easy! if the illuminated field is 27mm wide without the reducer, it will be 27 x 0.63 = 17mm with it in place. Can you help me? You can probably eke out 1.2 without noticing serious vignetting, which is a field stop of 31.5mm. 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. 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. 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. Reducer - Corrector Learn More. 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"). Also read the reviews here, including those at 4 stars. 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. Upgrading the Focuser of Your Schmidt-Cassegrain Telescope - Agena Astro To test this, I used three set-ups: 1. These reducers can also be used for visual observing with SCT scopes with eyepieces with a field stop as large as 24-27mm. A few people have reported issues with the male SCT thread diameter on this item being a bit larger than necessary. OPT Product Number: AE-SCTFR specifications Warranty 2 Year Warranty Works as advertised! Regardless, the difference was miniscule and is more than adequate on both and exceeds a 8 or 6 SCTs baffle tube diameter. It's highly unlikely that they could be so precisely identical unless they were. Right off the bat, I was struck by how similar the two R/Cs were. 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. More details are found in the Appendix of this article. Thks for that and its not for visual it for astrophotography. 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. 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. In terms of reduction and correction which are what reducer/correctors are supposed to do both are superb. I was referring to the C6 to answer you specifically. The C8 has no noticeable vignetting with a 32mm Plssl in the f/6.3 reducer. The problem with those SCT reducers is that they cause chromatic aberration and require refocusing when using parfocal RGB/other filters. InternetSales@optcorp.com, 800-483-6287 Reducer Lens .7x - EdgeHD 800 Have always disliked the crude, noisy SCT threads, but I get it. This innovative software solves the time-consuming problem of trying to pinpoint the North Celestial Pole. Contiguous US Customers:All items we sell ship for free within the Contiguous US. Depending on the design of the telescope, they may require separate focal reducers if they require focal reducers at all. Bear in mind you can't squeeze blood out of a turnip, i.e. Rather than a direct side-by-side, I swapped the reducers so that I was using them on the exact same, well-collimated instrument. Anyway, when purchased my R/C the "original" Celestron unit was not readily available and was offered instead the one sold under the shop's own label (in my case Tecnosky, but I saw the same product offered under TS label). 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. Performance wise what differences might there be using the reducer on a smaller scope. I'd favor the Japanese Celestron version over the others that are commercially available. Focal Reducers - Complete Overview and Function - YouTube 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. This focal reducer is made to attach to the rear cell of Schmidt-Cassegrain or Maksutov-Cassegrain telescopes. Benefits limited to hardware and conditions? The stars at the edge could be worse or better. Yellow and orange members of open clusters stood out a bit more as the various stars displayed their individuality. Celestrons FREE planetarium app is an astronomy suite that redefines how you experience the night sky. Dedicated focal reducers for refractors are intended primarily for imaging, not visual observation. Just one question. ED stands for "extra-low dispersion," which refers to the composition and optical properties of the glass used for the lenses. One of the most important factors in a telescope is its transmissionthe percentage of light that reaches the focal plane. The naming convention of SCT focal reducers is a little confusing. Sign up to get exclusive deals, observing tips, and new product announcements. With the Celestron Reducer/Corrector Lens, thats precisely what you get. While most Barlow lenses and focal extenders work with most kinds of telescopes available to amateur astronomers, focal reducers are designed to work in a narrow range of focal ratios of a telescope objective. ), 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. Reducer Lens .7x - EdgeHD 800 Learn More. 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. 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. Figure 2 shows the effective of a focal reducer on the light from a telescope objective. 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. Designed distancing using the reducer with a 1.25 visual back and 1.25 Televue mirror diagonal; We have corrected # (iii) after equations 6 & 7. This factor is designated by a power that is less than 1, and it usually lies between 0.5x or 0.8x. Celestron Solar Safe filter technology is GUARANTEED SAFE for direct solar observation and has been independently tested by SAI Global Assurance Services. I was going to measure the difference in grams, but my lovely wife caught me trying to use her precious, high-tech kitchen scale for the cause, and put the kibosh on it. The distances d1 andd2 can also be expressed in terms of the focal length of the focal reducer FR with the lens equation: Using Equation 2, Equation 1 can also be expressed in terms of d2: The focal reduction factor of the focal reducer depends on its focal length and its distance from the focal plane of the objective as shown by Equation 4: Again, for example, when the focal reducer is placed at the original focal plane of the objective, d1=0 and MR=1, which means there is no focal reduction. 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. In every configuration, there were essentially parfocal, requiring only a tiny fine focus adjustment when changing correctors. The more focal reduction, the further inward the focal plane will be. The working distance or required back focus, explained above, is usually specified and is far more important in practice. Oceanside Photo & Telescope wants our customers to shop with confidence knowing that you will always get the best deal available. USD $80.00. Explore Scientific Keys to the Universe Sale, Antares f/6.3 Focal Reducer for Schmidt-Cassegrain Telescopes, Skip to the beginning of the images gallery. Antares f/6.3 SCT Focal Reducer - Rother Valley Optics Ltd Focal Reducer for SCT - ACF - Stargazers Lounge I have/had both the Celestron (Japan) and Antares units. Images in the Celestron tended to appear ever-so-slightly dimmer (maybe? 2. Antares f/6.3 Focal Reducer for Schmidt-Cassegrain Telescopes - Agena Astro Sharpness is essentially the same. Focus misses by about 1 turnof the focus knob.Here is my solution:Buy a shorter 1.25 visual back for my scope. Explore Scientific - Keys to the Universe Sale. 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. Celestron or Antares? Your eyepieces are the first accessories you should learn to use with your telescope. Many focal reducers for refractors have a working distance (or back focus distance) of 55mm. But in the end they both do pretty much the same thing and it sounds like any performance difference is subtle. As one increases, the other decreases. Community Forum Software by IP.BoardLicensed to: Cloudy Nights, E of San Francisco Bay and W of the Awahnee, This is not recommended for shared computers, reviews here that suggest a coating problem, Back to Celestron Computerized Telescopes, Looking for advice on first refractor and camera. 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. For example, with a 0.8x focal reducer, a telescope with a focal length of 800mm will operate at 800 x 0.8 = 640mm when the reducer is placed at the working distance specified by the manufacturer. Clean, fun jokes the tradition continues - Page 106 And when used in some refractors, the field flattening is not as accurate as it is in the f/10 SCTs. 1.2" in that scope is a field stop of 43mm at f/10 and 27mm at f/6.3. 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. Hello! A former wireless communications consulting engineer and management consultant to various Fortune 500 companies, Manish started Agena AstroProducts in 2003. Start Chat I've looked through one from Meade and first impression was that it was like the Celestron version. DUE TO EXTREMELY HIGH DEMAND, WE WILL NOT BE TAKING NEW ORDERS UNTIL MONDAY, DECEMBER 14. 2023 OPT Telescopes. 800-483-6287 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. 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. 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. Celestrons award-winning Nature DX binocular gets a major upgrade with the addition of ED objective lenses. Looking forward to the day when I can do a shoot-out between a Japan and China Celestron, just for kicks. A focal reducer does just the opposite of a Barlow lens or focal extender. 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. I doubt there is any difference between the Antares and the Celestron except price. Focal reducers also move the effective focal plane of the objective inward, that is, towards the objective (see Figure 1). 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. This filter threads on to the rear cell of your Celestron or Meade SCT telescope. That means the base of the mounting threads of the focal reducer needs to be 55mm from the camera sensor to achieve the design reduction factor, which is usually 0.8x or 0.85x. 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. I wont bother with differences in packaging, caps, etc. For imaging, a T-adapter is threaded to the camera side of the focal reducer, which in turns connects to the camera with the appropriate hardware. The equations in the Appendix show how this all works. 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. Easy solution found a very tiny dab of super lube on the threads and all was well and quiet.. Antares F/6.3 SCT Focal Reducer | OPT Telescopes 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. I've heard and read all kinds of things about the Antares being only a reducer and not a corrector, etc. If yes, what kind of focal reducers can I use? Astro-Tech Schmidt-Cassegrain f/6.3 Focal Reducer Field Flattener I don't know. This is the simplest way to attach your ASI121 to your telescope. Not one detectable iota of discernable difference. Celestron is considered better in terms of QA, less likely to come with free dust, hair or fingerprint. Never noticed any anomalies with this unit. Powered by Invision Community. That said any comparison reviews are helpful. Maybe I got a lemon. The lens is housed in machined aluminum for are machined aluminum black anodized. Free shipping $189.95 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. Agena's Guide to Focal Reducers - Agena Astro 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. Generally, views through the Antares seemed a little more transparent and brighter. 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. CPWI has an extensive object database, employs PointXP mount modeling, and more. I would not use the reducer with a 2" diagonal or eyepiece in the C6. I have this one Opticstar F6.3 Focal Reducer / Corrector. ), but stars seemed a bit tighter and their colors were richer and more dramatic. Perhaps not exactly- there will be some uncertainty because of manufacturing tolerances and so forth, but it will be close. Since the Celestron and Antares are supposed to have different focal lengths and spacing specs, I expected different results. We will match any online price that we confirm as valid. In terms of reduction and correction - which are what reducer/correctors are supposed to do - both are superb. Obviously bright objects like Jupiter or The Moon show the reflections. 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 Antares focal reducer comes in small box. These reducers can also be used for visual observing with SCT scopes with eyepieces with a field stop as large as 24-27mm. I've seen some older threads saying that the Celestron, Meade and Antares FRs are all the same and manufactured in the same factory. Never used one, but read the reviews here that suggest a coating problem. 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. Increase that distance, and greater reduction results and visa versa. I've seen some older threads saying that the Celestron, Meade and Antares FRs are all the same and manufactured in the same factory. Thanks for any advice or experience you could share. 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. Thanks. 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? Thanks for pointing this out. But in the Japan version I have never noticed any anomaly like the ghosting in the China R/C. This may be a problem if the focuser tube or the diagonal (for visual observing) is too narrow to accept light at this larger angle. But while the image gets brighter, the size of the image circle gets proportionately smaller. 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. Perfect for the serious student, professional scientist and discriminating hobbyist. Reproduction without permission prohibited. Please re-enable javascript to access full functionality. This fully multi-coated lens provides maximum light transmission with near full-field illumination. Hmmm . Some third-party vendors also make reducers for SCT scopes. Reducer Lens .7x - EdgeHD 1100 - Celestron However, the China 6.3 R/C has noticeable internal reflections that I haven't figured out yet. Please Log in to save it permanently. We have tested our current batch and it works with Meade, Celestron, and Baader SCT accessories. F6.3 Focal reducer for F/10 or higher telescopes, 43mm aperture, 4-Element, Fully Multicoated. Celestron Reducer Lens .7x - EdgeHD 925 The EdgeHD .7x Focal Reducer Lens makes your EdgeHD 925 one full F-Stop faster than f/10, reducing your exposure time by half to capture the same brightness of object 5-element lens design Maintains similar. * Not a Retail Store * 16313 Arthur StreetCerritos, CA 90703, USA, Availability: Item has been discontinued by Agena and we no longer carry this item. External Focusers for Schmidt-Cassegrain Telescopes 3.1 The Basics of SCT Threads All rights reserved. CPWI has an extensive object database, employs PointXP mount modeling, and more. Over the course of a several nights of general observing, I swapped back and forth between the Antares and Celestron R/Cs on a wide variety of objects open clusters, brighter galaxies, a couple of nebulae, and globular clusters as well. Reducer - Corrector | Celestron For the best experience on our site, be sure to turn on Javascript in your browser. Some coma is visible in the corners, but the image is quite good for EAA applications. 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. 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. Wonder how they would stack up with a Japanese 6.3. I'm going with the Celestron. Because I have not heard any complaints about the made in China R/C. Figure 1 shows the relationship between the focal reduction factor MR and the position of the reducer in the optical path. Description. I have Hirsch focal reducer, which is yet another clone of the Celestron reducer. My Celestron was made in China and the Antares in Canada. JavaScript seems to be disabled in your browser. Meade and Celestron both sell such SCT-T adapters with the correct optical length. If you want to save a few buck watch the classifieds on CN. He tested this on an 8 Celestron , I have a Celestron 6SE. 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. The two samples I have PERFORM IDENTICALLY. 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. They are designed (assuming you are referring to the f/6.3 version) for the f/10 light cone.