Copyright 2021 Stargazers Lounge The telescope side of the barrel is often threaded with an M48 x 0.75 thread for standard 2" astronomy filters. As another example,GSO makes focal reducers for their line of Ritchey-Chretien imaging telescopes. 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. 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. The focal length of a focal reducer is usually measured from the rear lens surface of the reducer (and not the reducer's housing). They are also less expensive than many external focusers of similar build quality. 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. . Copyright 2003-2022 Agena AstroProducts. Start Chat Torazz 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. Sign up to get exclusive deals, observing tips, and new product announcements. The threads were similar on the eyepiece end, but a bit smoother. The amount of reduction is simply the percentage by which a reducer shortens the effective focal length of a telescope and is calculated as (1 Reduction Factor) x 100%. 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. Go behind the scenes with Celestrons product development team and learn more about our award-winning and patented innovations. What an enjoyable read and detailed comparison. 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. I use it on my C8 SCT with a 1000d, and it seems to do everything written on the tin. 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. 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 . 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. 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. Completely stuck, completely frustrated. 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. 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. However, I noticed immediately that the Antares had a bit more of an heft to it, giving it a solid feel the Celestron didnt possess. However, the export of some items may be restricted outside the US due to size or manufacturer restrictions. 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. Assuming you use the reducer with the stock 1.25" diagonal, it will operate at f/6.3. 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. This focal reducer from Celestron reduces the effective focal length by 0.63X Enjoy the wider field of view & faster exposure times at f/6.3 with f/10 telescopes f/11 telescopes, such as the C14 will perform at f/7 The Celestron f/6.3 Reducer has four fully-multicoated elements Reduce your exposure times by a factor of 3! In the 1960s, Celestrons founder, Tom Johnson, created groundbreaking new telescopes never before seen on the consumer market. The stock Celestron visualback is just under 2 long. None of this was offensive, nor did it interfere with views in any significant way. 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. 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. Images in the Celestron tended to appear ever-so-slightly dimmer (maybe? Article Agena AstroProducts, 2019. Free shipping $189.95 There will be no shipments on 3/1/2023, 3/2/2023, or 3/3/2023 (March 1st - March 3rd, 2023). 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. So it provides a 0.63x design reduction factor when used with an f/10 SCT at the specified working distance. I would pay slightly more for the Japan produced version, just because Hirsch was not bad either but sold it since I had 2 already. Due to the design, the Reducer/Corrector lens does diminish a small amount of field curvature common to all Schmidt Cassegrain telescopes but does not eliminate it. 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. The equations and argument in the Appendix of this article shows the relationship between the working distance and the reduction factor. This focal reducer is made to attach to the rear cell of Schmidt-Cassegrain or Maksutov-Cassegrain telescopes. Thanks guys, appreciate the feedback. 2. Oceanside Photo & Telescope wants our customers to shop with confidence knowing that you will always get the best deal available. The naming convention of SCT focal reducers is a little confusing. There is one difference though the Antares came with only one lens cap whereas the Celestron had a cap for both ends. Just one question. For the best experience on our site, be sure to turn on Javascript in your browser. Our proprietary StarBright XLT optical coatings dramatically increase transmission, up to 97.4% on our Schmidt corrector lenses. 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. A little longer light path with a 2 Baader click-lock, low profile 1.25 adapter, and the 1.25 diagonal; 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). Meade does not make an equivalent line of focal reducers for the ACF scopes, although some models of Meade ACF are already at f/8, faster than the f/10 ratio of Celestron Edge HD scopes. 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. We only send interesting emails and will never sell your data. Even though they may have been slightly dimmer, galaxies were a bit easier to tease out of the urban light soup I deal with. 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. Hello! Fumbling around in the dark, fine threads might be a problem. and you will be fine. Better images are also obtained when using these focal reducers at a reduction factor of 0.5x 0.8x, approximately. Thanks for any advice or experience you could share. Some faster refractors with a focal ratio of f/6, for example, only require field flatteners and not focal reducers. InternetSales@optcorp.com, 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. He tested this on an 8 Celestron , I have a Celestron 6SE. 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. However, this also came at a cost, as the sky background in the Antares was slightly brighter. Looking forward to the day when I can do a shoot-out between a Japan and China Celestron, just for kicks. 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. Have a promo code? I've seen some older threads saying that the Celestron, Meade and Antares FRs are all the same and manufactured in the same factory. More details are found in the Appendix of this article. Again, to my surprise, there was absolutely no difference between the Celestron and Antares on any star. However, because the field curvatures in refractors and SCTs vary a lot, I would predict unpredictable effects inre: field curvature. Reducer Lens .7x - EdgeHD 800 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. As mentioned in Section 2.3, the reduction factor for these focal reducers can be varied by adding spacers to move the reducer further from the camera sensor or eyepiece. External Focusers for Schmidt-Cassegrain Telescopes 3.1 The Basics of SCT Threads Start here to find the perfect telescope for you!
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