He received his first telescope at the age of 5 and completed his first university course in astronomy at the age of 12, eventually receiving a master's degree in the subject. Again, to my surprise, there was absolutely no difference between the Celestron and Antares on any star. Place the plastic covers on the lens when not in use to reduce the dust collection. First, let's have a look at some key optical parameters are needed to understand focal reducers. Reducer Lens .7x - EdgeHD 1400 Some third-party vendors also make reducers for SCT scopes. 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. 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. I wish there was. How does it look thats what matters. Edited by Tony Bonanno, 16 April 2021 - 06:44 PM. Figure 2 shows the effective of a focal reducer on the light from a telescope objective. 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. With spring galaxy season here, I decided to pick up a couple more to compare in a head-to-head shoot out. The same illumination you have at the edge of a 27mm field, the C8 has at the edge of a 38mm field. I also used several eyepieces including the ES 24mm/68, 17.5mm and 12.5mm Morpheuses, and a 10.5mm Pentax XL. 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. High power views will provide flatter fields all the way to the edge, both visually and photographically. This rugged, 3-in-1 device features a true tactical 3-mode flashlight, a hand warmer, and a portable power bank for recharging your personal electronics on the go. if the illuminated field is 27mm wide without the reducer, it will be 27 x 0.63 = 17mm with it in place. In both cases will end with a similar tfov. Upon close inspection, it was clear that the housing of Antares assembled in Canada version was a little more substantial than the Celestron. When the camera sensor is placed at this distance, the reduction factor of these reducers is 0.75x. But while the image gets brighter, the size of the image circle gets proportionately smaller. You attach the focal reducer to the rear port on a SCT and can keep it covered. Explore Scientific - Keys to the Universe Sale. An eyepiece with a 27mm field stop yields a true field of 1.03 in the C6 at f/10. The female end attaches to the rear cell of the telescope. The stars at the edge could be worse or better. Since then, Agena has become one of the leading online retailers of telescopes and astronomical accessories worldwide. That was fun. Does anyone know if the Antares 4000 focal reducer is as good as the Celestron focal reducer. My experience is that CN sellers are way above those listing elsewhere. The most significant mechanical variation, however, is the quality and precision of the threading. Focal reducers also move the effective focal plane of the objective inward, that is, towards the objective (see Figure 1). 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. 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. Torazz 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. Here, there was a subtle difference . I don't know. 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. ED stands for "extra-low dispersion," which refers to the composition and optical properties of the glass used for the lenses. I focus using a moonlight electronic focuser and focusmax. Your eyepieces are the first accessories you should learn to use with your telescope. We have tested our current batch and it works with Meade, Celestron, and Baader SCT accessories. We will be glad to help. The resultant reduction factor was measured to be 0.46x. This focal reducer is made to attach to the rear cell of Schmidt-Cassegrain or Maksutov-Cassegrain telescopes. Since the focal length of the reducer, FR, is fixed, as d2 increases then MR decreases. The C8 has no noticeable vignetting with a 32mm Plssl in the f/6.3 reducer. For visual use, this means you get lower power with the same eyepiece and a wider field of view. But when not in the box or on the telescope, there is no cover for the other end. I was referring to the C6 to answer you specifically. There are also third-party vendors such as Hotech. It was also a little brighter in the center of the field with subtle darkening in the outer 20% or so. However, it will not thread into William Optics accessories, and with GSO it is a hit or miss. Unlike . Thanks guys, appreciate the feedback. The focal length and design working distance for this focal reducer were not available from the manufacturer. I've never found my 0.63 reducer causing CA when used with my SCT. 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. The more focal reduction, the further inward the focal plane will be. If used with other f/ratios, the field flattening characteristic may be unpredictable. 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. You currently have javascript disabled. Because I have not heard any complaints about the made in China R/C. Celestron & Antares f/6.3 Reducer/Corrector Shoot-out Rather than a direct side-by-side, I swapped the reducers so that I was using them on the exact same, well-collimated instrument. 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. Celestron or Antares f/6.3 focal reducer for SCT? I use it on my C8 SCT with a 1000d, and it seems to do everything written on the tin. Whereas the Celestron threaded smoothly onto the scope, the Antares chattered and squeaked a bit more so when being removed. 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. It seems right to put some distance between the camera and the focal reducer, right? However, some focal reducers can be used over a wider range of working distances, especially those with simpler optical design, and especially when used with cameras with smaller sensors. This award-winning optical system reduces visual defects like field curvature and coma, creating an ultra-flat field for pinpoint stars all the way to the edge of todays largest imaging sensors. For me the Antares was a little brighter and had the least scatter by a bit so the better coatings won. Depending on the design of the telescope, they may require separate focal reducers if they require focal reducers at all. 2023 OPT Telescopes. The Antares focal reducer comes in small box. But the smaller image circle means there is a limit to the field stop of an eyepiece that can achieve an unvignetted image. Copyright 2021 Stargazers Lounge Most refractor manufacturers such as William Optics, Tele Vue Optics, Explore Scientific, Sky-Watcher, William Optics, and Stellarvue make their own focal reducers optimized for use with their telescopes. One problem with getting opinions is that most of use do not have both reducers or have never done a side by side comparison. I am a purely visual observer, so will evaluate for visual use only. 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. I use the same back spacing for both on a small 6" Celestron SCT. That is definitely a 2" eyepiece, but it is not a large or long focal length 2" eyepiece. For this test, I used a single configuration R/C, Click-lock, and 1.25 diagonal with the adapter. Each focal reducer has a fixed specification called the working distance or required back focus. 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. Just one question. I even lost track of which reducer I was using. 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. The Antares is supposed to be pretty comparable. More aggressive reduction, or using these reducers with larger sensors, will result in aberrations and distortions near the edge of the image. because they really dont matter. No small animals were harmed in making these observations. a Tele Vue Panoptic), or a Plossl eyepiece with an apparent field of view of 50 and a focal length of 32mm. Many Ritchey-Chretien telescopes available today are made by GSO. I use the Celestron version and it seems OK for both visual and imaging. We will match any online price that we confirm as valid. But in the Japan version I have never noticed any anomaly like the ghosting in the China R/C. 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. Celestrons patented StarSense Technology makes it easier than ever to locate objects in the night sky, even if youve never used a telescope before. 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. For the best experience on our site, be sure to turn on Javascript in your browser. 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. 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. Brian Ventrudo is a writer, scientist, and astronomy educator. I have this one Opticstar F6.3 Focal Reducer / Corrector. The f/6.3 reducer is operating at f/5-f/5.5 with a 2" diagonal, depending on the back focus length of the diagonal. If used before or beyond the working distance, unwanted image distortion may result. It is not a corrector or flattener. 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. 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. 0.5X focal reducer for Celestron, Meade, and Orion CCD imaging cameras 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. That includes, for example, a 1.25" eyepiece with an apparent field of view of 68 and a focal length of 24mm (eg. I wonder whether, for example, Antares focal reducer for SCT belongs to the latter category. 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. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. The nominal design reduction factor of these reducers is typically 0.5x. 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 . In this configuration, the 29.5mm camera nosepiece and a 6mm extension ring positions the reducer at a working distance of 53.5mm from the camera sensor, which is located 12.5mm inside the front edge of the camera. 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. Perhaps not exactly- there will be some uncertainty because of manufacturing tolerances and so forth, but it will be close. Thanks for any advice or experience you could share. With the Celestron Reducer/Corrector Lens, thats precisely what you get. This appendix summarizes how this works based on simple equations from the book Telescope Optics by Rutten and van Venrooij. 160K views 9 years ago This video is a complete overview of focal reducers and how they function applying to telescopes. My Celestron was made in China and the Antares in Canada. 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. InternetSales@optcorp.com, 800-483-6287 Check out our 2022 telescope buying guide here! I've seen some older threads saying that the Celestron, Meade and Antares FRs are all the same and manufactured in the same factory. 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. A useful thing to know is how far from the objective lens (for a refractor) is the focal reducer located. The lens is housed in machined aluminum for are machined aluminum black anodized. 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. Antares F/6.3 SCT Focal Reducer | OPT Telescopes But is there a difference in quality between the Antares and the Celestron or Meade focal reducers? Celestron is considered better in terms of QA, less likely to come with free dust, hair or fingerprint. They are designed (assuming you are referring to the f/6.3 version) for the f/10 light cone. Does anyone know if the Antares 4000 focal reducer is as good as the Celestron focal reducer. Please re-enable javascript to access full functionality. Meade once made an f/3.3 focal reducer for SCT scopes. And, the reality is that every F/6.3 RC out there Celestron, Hirsch, Astromania, etc., etc. Dedicated focal reducers for refractors are intended primarily for imaging, not visual observation. However, the export of some items may be restricted outside the US due to size or manufacturer restrictions. These reducers have a back focus (or design working distance) of 80mm. Orders placed over the weekend will be shipped on the following Monday. 800-483-6287 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. CPWI has an extensive object database, employs PointXP mount modeling, and more. As a result, the smaller tube may cut into the light cone and effectively reduce the working aperture of the telescope. Telescope Focal Reducers & Correctors - High Point Scientific Very helpful, thanks a lot for this article! Since 2008, Brian has taught astronomy to tens of thousands of stargazers through his websites OneMinuteAstronomer.com and CosmicPursuits.com. He tested this on an 8 Celestron , I have a Celestron 6SE. Melotte 15 - First Process in PixInsight (easy! 0.63x Starizona Focal Reducer for SCTs- Awesome Astrophotography 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. Besides observing from his heavily light polluted backyard in Los Angeles, Manish enjoys conducting astronomy outreach programs in local schools. However, some focal reducers can be used on other models of telescopes, but this is not always possible. A little longer light path with a 2 Baader click-lock, low profile 1.25 adapter, and the 1.25 diagonal; To test this, I used three set-ups: 1. This is a. An f/6.3 reducer is designed to reduce the focal ratio of an f/10 SCT to f/6.3. If the reducer is placed closer to the eyepiece or camera than the distance D, the reduction factor decreases. Since the Celestron and Antares are supposed to have different focal lengths and spacing specs, I expected different results. Celestron Nexstar+ 127 SLT, several budget plossl eyepieces, Celestron 8-24mm zoom EP and a 12.5mm illuminated double reticle EP, Svbony SV205 camera w/.5 focal reducer, Celestron SkyMaster 20x80 binos on a 40 yr old QuickSet PanHead tripod, Stellarium, Sharpcap and ManyCam on my laptop, SkyView and Nightshift on my phone and a dandy little $9 . Yellow and orange members of open clusters stood out a bit more as the various stars displayed their individuality. Obviously bright objects like Jupiter or The Moon show the reflections. If it's positioned further from the eyepiece or camera and closer to the telescope objective, the reduction factor increases. Your price: $579.00. The female end attaches to the rear cell of the telescope. An image of about 24mm across, approximately, allows an observer to use a 1.25" eyepiece with a maximal field stop. Planetarium software package which provides easy-to-understand explanations and impressive visuals of all kinds. Easy solution found a very tiny dab of super lube on the threads and all was well and quiet.. Fortunately, my neighbors are not out in their backyards at 11 pm, or they may have thought I was torturing a small mammal. 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. Equation 6 & 7 item two & three does not make sense, both say increase its reduction (one should say reduce its reduction?). Wonder how they would stack up with a Japanese 6.3. We reserve the right to verify a competitor's advertised price and the availability of the item. Antares f/6.3 Focal Reducer for Schmidt-Cassegrain Telescopes - Agena Astro In the 1960s, Celestrons founder, Tom Johnson, created groundbreaking new telescopes never before seen on the consumer market. Therefore, a 55mm back focus with a filter that is 3mm thick added to the imaging train would become 56mm. 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. 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. Will not focus with the stuff I have. It features a standard male SCT thread (2" OD, 24 TPI) on one side and a standard SCT female thread on the other. 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. 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. More about this below. Can you tell me about the use of reducers in Maksutov-Cassegrain telescopes?
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