If used with other f/ratios, the field flattening characteristic may be unpredictable. Housings, threads, reduction, correction, blah, blah, blah. Perfect for the serious student, professional scientist and discriminating hobbyist. Who cares? Generally, views through the Antares seemed a little more transparent and brighter. Optically, it consists of a four-element lens that is fully multi-coated for high contrast and resolution. I have this one Opticstar F6.3 Focal Reducer / Corrector. Sign up for our newsletter to get exclusive deals, observing tips, and new product announcements. But when not in the box or on the telescope, there is no cover for the other end. Antares f/6.3 Focal Reducer for SCTs - Awesome Astro 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. 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. We have tested our current batch and it works with Meade, Celestron, and Baader SCT accessories. Fumbling around in the dark, fine threads might be a problem. Astro-Tech Schmidt-Cassegrain f/6.3 Focal Reducer Field Flattener However, even though the imprint on the item states "Reducer / Corrector" please note that his is a reducer only. 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. Best evidence would by obtained by using a camera and evaluating the image both by eye and with a computer analysis. The key points are as follows: So just remember that a smaller distance (from the camera or eyepiece) means a lower amount of reduction (and vice versa). Place the plastic covers on the lens when not in use to reduce the dust collection. This telescope control software replaces the hand control and allows the user to remotely control their Celestron computerized telescope from their personal PC or laptop. No idea what the issue is. There are also third-party vendors such as Hotech. An f/6.3 reducer is designed to reduce the focal ratio of an f/10 SCT to f/6.3. Here, there was a subtle difference . Reducer Lens .7x - EdgeHD 800 Thanks for pointing this out. Never used one, but read the reviews here that suggest a coating problem. Not noticed any optical problems. 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. control and Sky Viewer display makes selecting your target easy. More aggressive reduction, or using these reducers with larger sensors, will result in aberrations and distortions near the edge of the image. And, the reality is that every F/6.3 RC out there Celestron, Hirsch, Astromania, etc., etc. 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. As a result, the smaller tube may cut into the light cone and effectively reduce the working aperture of the telescope. There will be no shipments on 3/1/2023, 3/2/2023, or 3/3/2023 (March 1st - March 3rd, 2023). Celestron or Antares f/6.3 focal reducer for SCT? Explore Scientific Keys to the Universe Sale. They provide 0.75x focal reducers for these telescopes that takes an f/8 instrument down to f/6. Focal Reducers - Complete Overview and Function - YouTube 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. This focal reducer and field flattener consists of a four-element multicoated 40mm lens in a metal cell. * Not a Retail Store * 16313 Arthur StreetCerritos, CA 90703, USA. We only send interesting emails and will never sell your data. Once focused it's pretty good. It works fine but you should stick with 1.25 EPs; or can use 2" EPs without corrector. The lens has a knurled surface, providing a tremendous gripping surface for threading/unthreading. WiFi technology encircles the globe in a web of connectivity, knowledge, and information. M44 was a perfect target for this, as its large size maxes out the FOV on a C8 with a corrector, and its bright stars make great targets for measuring the very edge of the visible field. For this test, I used a single configuration R/C, Click-lock, and 1.25 diagonal with the adapter. Designed distancing using the reducer with a 1.25 visual back and 1.25 Televue mirror diagonal; In such cases, we will be happy to take the item back as per our standard return terms. 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. So, if you have a filter that is 3mm thick, you need to add 1mm of spacing to your imaging train to retain the correct back focus. CPWI has an extensive object database, employs PointXP mount modeling, and more. No negative issues to report. Your eyepieces are the first accessories you should learn to use with your telescope. 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. JavaScript seems to be disabled in your browser. Also, the focusers of most Newtonians do not have enough in-travel to accommodate a focal reducer. I even lost track of which reducer I was using. But nearly every observer who installs one of these devices is pleased with their performance. Manish Panjwani has been an active amateur astronomer since before Halley's Comet last flew by our neighborhood. But the smaller image circle means there is a limit to the field stop of an eyepiece that can achieve an unvignetted image. This is a. F 6.3 focal reducer/corrector. - Discussions - Stargazers Lounge 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. The visual back must be removed first. Again, to my surprise, there was absolutely no difference between the Celestron and Antares on any star. Better images are also obtained when using these focal reducers at a reduction factor of 0.5x 0.8x, approximately. Celestrons patented StarSense Technology makes it easier than ever to locate objects in the night sky, even if youve never used a telescope before. Such an image circle is still large enough to encompass the relatively large sensor of many deep-sky astronomy cameras. Some refractors such the TeleVue Nagler-Petzval (NP), the Takahashi "FSQ", and the William Optics Redcat/WhiteCat 51 have inherently flat fields because of internal optical elements. Meade and Celestron both sell such SCT-T adapters with the correct optical length. A useful thing to know is how far from the objective lens (for a refractor) is the focal reducer located. 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. If the reducer is placed closer to the eyepiece or camera than the distance D, the reduction factor decreases. 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. 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. 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. I have had the Japan unit on the back of my C5 since 1994 or thereabouts. That was fun. Focus misses by about 1 turnof the focus knob.Here is my solution:Buy a shorter 1.25 visual back for my scope. Just one question. Many focal reducers for refractors have a working distance (or back focus distance) of 55mm. 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. OPT Product Number: AE-SCTFR specifications Warranty 2 Year Warranty Works as advertised! Equation 6 & 7 item two & three does not make sense, both say increase its reduction (one should say reduce its reduction?). The telescope side of the barrel is often threaded with an M48 x 0.75 thread for standard 2" astronomy filters. No results, please adjust your filters. This also resulted in the clear aperture of the Antares being about 39-39.5mm, versus the Celestrons 41mm. Watch this before you buy Celestron 8SE SCT, or a Focal Reducer or a So Celestron buyers like Celestron, Meade buyers like the Meade and Antares buyer like the Antares. Please Log in to save it permanently. ), but stars seemed a bit tighter and their colors were richer and more dramatic. Reducer Lens .7x - EdgeHD 800 Learn More. 2. Steve External Focusers for Schmidt-Cassegrain Telescopes 3.1 The Basics of SCT Threads Ive owned Celestron, Meade, and Antares models over the years at least a couple of each. Antares or Celestron? 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 Japanese version and although I haven't used it in quite awhile, the views through it were superb with no internal reflections at all. The two samples I have PERFORM IDENTICALLY. 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. Shipping will be via the cheapest shipping method which will vary depending on the items in your order. All Rights Reserved. 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. 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. Sign up for OPT news, exclusive offers, and updates on the latest gear! Since the focal length of the reducer, FR, is fixed, as d2 increases then MR decreases. I've looked through one from Meade and first impression was that it was like the Celestron version. They are reported as identical. 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). By 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. 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. Torazz Can these economical focal reducers from GSO and other vendors result in good images? 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. You need to be a member in order to leave a comment. I focus using a moonlight electronic focuser and focusmax. In practice, it's important to remember that you will rarely operate at the exact working distance and at the exact reduction factor that is specified. Refractors, or SCTs with external focusers, may not have sufficient in-travel to reach focus in some configurations. Reducer Lens .7x - EdgeHD 1400 I had a Celestron, Antares and Hirsch for awhile and compared them over about a year. With the Celestron Reducer/Corrector Lens, thats precisely what you get. My Celestron was made in China and the Antares in Canada. This filter threads on to the rear cell of your Celestron or Meade SCT telescope. 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. As I understand it, compared to the old Meade SCT's, the ACF is already "coma corrected", so the standard Meade, Celestron etc F6.3 focal reducers are not suitable and will only worsen the images. From the SkyProdigy, a telescope so smart it can align itself, to our high-performance EdgeHD optical system, weve revolutionized the hobby of astronomy for beginners and advanced amateurs alike. To calculate how much back focus spacing you need to add, take the thickness of the filter and divide it by 3. However, these will not impact optical performance. It is recommended for . But in the end they both do pretty much the same thing and it sounds like any performance difference is subtle. The design reduction factor of a focal reducer is the relative amount by which the effective focal length of the telescope is reduced when the focal reducer is used at its specified working distance or back focus. You don't need to follow these equations to use a focal reducer, but they do show how the reduction factor changes with the placement of the reducer. Style: USD $80.00. This focal reducer is made to attach to the rear cell of Schmidt-Cassegrain or Maksutov-Cassegrain telescopes. However, some focal reducers can be used on other models of telescopes, but this is not always possible. I found both to be very good. A little longer light path with a 2 Baader click-lock, low profile 1.25 adapter, and the 1.25 diagonal; I only have the Celestron f/6.3. 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. 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). First, I wanted to compare the actual reduction provided by these competitors, as many threads here cite different ideal spacing from the reducer to eyepiece focal plane to achieve the correct f/6.3 result. 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. 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