Your eyepieces are the first accessories you should learn to use with your telescope. Reproduction without permission prohibited. . Here, there was a subtle difference . 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. 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. But the diameter of the image circle decreases by a factor of 0.63 to about 24mm. With both, using the same diagonal set-up, the exact same stars were visible at the very edge of the FOV. We do not price match competitors if they are out of stock. Since the Celestron and Antares are supposed to have different focal lengths and spacing specs, I expected different results. A few large telescopes and mounts are excluded from this free shipping offer. One of the most important factors in a telescope is its transmissionthe percentage of light that reaches the focal plane. More aggressive reduction, or using these reducers with larger sensors, will result in aberrations and distortions near the edge of the image. The Antares is supposed to be pretty comparable. Well done. For the best experience on our site, be sure to turn on Javascript in your browser. I don't know. It is not a corrector or flattener.
[email protected]. Unleash the full pointing accuracy of your Celestron computerized telescope with a specialized telescope control software suite. If you want to use them for visual - try maybe long focal length eyepieces rather than the reducer. Start Chat More important, its clear that the Antares is a reducer/corrector, just like the Celestron and not merely a reducer. The same illumination you have at the edge of a 27mm field, the C8 has at the edge of a 38mm field. October 11, 2010 in Discussions - Scopes / Whole setups. The working distance or required back focus, explained above, is usually specified and is far more important in practice. 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. For me, I was looking for, and planning to keep, the one that yielded the greatest reduction. Have always disliked the crude, noisy SCT threads, but I get it. It's an either/or proposition: reducer and 1.25", or 2", but not 2" and reducer. Specially-designed focal reducers are available for use with these telescopes. 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. 3. No retailers currently carry this product. The reduction factor MR can also be written in terms of d2 as: When the focal reducer is placed at the working distance, D, that is when d2=D, then the reduction factor MR is equal to the design reduction factor MRD: Equations (6) and (7) imply these important considerations: Most manufacturers do not publish the focal length of their focal reducers, so it is not usually possible to calculate the working distance and design reduction factor. But when not in the box or on the telescope, there is no cover for the other end. I've looked through one from Meade and first impression was that it was like the Celestron version. ED stands for "extra-low dispersion," which refers to the composition and optical properties of the glass used for the lenses. Not one detectable iota of discernable difference. 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. As another example,GSO makes focal reducers for their line of Ritchey-Chretien imaging telescopes. 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. . Generally, views through the Antares seemed a little more transparent and brighter. As one increases, the other decreases. Some are available in 1.25" barrel format but with C threads. Request stock alerts and we'll let you know when the item is back in stock. They only publish the value of D, the working distance (sometimes called the back focus distance) and the design reduction factor MRD. To test this, I used three set-ups: 1. 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. 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. 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. 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. because they really dont matter. - thanks. The Reducer/Corrector is easy to install by threading the unit onto the rear cell of your Schmidt-Cassegrain telescope (or the reducer plate of the C11 and C14). 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. Figure 2 shows the effective of a focal reducer on the light from a telescope objective. I really don't see any difference in the current crop except the "Meade" is usually the cheapest. For this shoot-out, I used a standard Celestron C8 with Starbright coatings. Stars had a tiny bit more sparkle and pop. However, the China 6.3 R/C has noticeable internal reflections that I haven't figured out yet. Celestron Focus Motor for SCT, EdgeHD & 8" RASA, Celestron C6 0.63 reducer/flattener back focus. Since 2008, Brian has taught astronomy to tens of thousands of stargazers through his websites OneMinuteAstronomer.com and CosmicPursuits.com. and you will be fine. If it's positioned further from the eyepiece or camera and closer to the telescope objective, the reduction factor increases. 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. My experience is that CN sellers are way above those listing elsewhere. Because I have not heard any complaints about the made in China R/C. They are designed (assuming you are referring to the f/6.3 version) for the f/10 light cone. Does anyone have any experience with the Celestron and Antares focal reducers? If used before or beyond the working distance, unwanted image distortion may result. I use the Celestron version and it seems OK for both visual and imaging. You currently have javascript disabled. Check out our 2022 telescope buying guide here! Many focal reducers for refractors have a working distance (or back focus distance) of 55mm. A little longer light path with a 2 Baader click-lock, low profile 1.25 adapter, and the 1.25 diagonal; Manish Panjwani has been an active amateur astronomer since before Halley's Comet last flew by our neighborhood. Increase that distance, and greater reduction results and visa versa. Edited by Tony Bonanno, 16 April 2021 - 06:44 PM. 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. 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. Focal Reducer, 2", 0.7X. 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. 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. We have tested our current batch and it works with Meade, Celestron, and Baader SCT accessories. 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. Most different was that the sky background was a little darker and more uniform, providing a tiny contrast boost for fainter objects. 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). Not a bit. Celestron Solar Safe filter technology is GUARANTEED SAFE for direct solar observation and has been independently tested by SAI Global Assurance Services. Meade once made an f/3.3 focal reducer for SCT scopes. 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. 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. I was referring to the C6 to answer you specifically. I also used several eyepieces including the ES 24mm/68, 17.5mm and 12.5mm Morpheuses, and a 10.5mm Pentax XL. But I am rusty, can you condense a bit for me please? However, manufacturers virtually never provide this specification. How does it look thats what matters. 3. 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. Details: The item must be the identical item, brand name, size, weight, color, quantity and model number. Wonder how they would stack up with a Japanese 6.3. 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. . As a Barlow's magnification increases with increasing distance from the Barlow, a focal reducer's reduction increases with increasing distance from the reducer. 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. Whereas the Celestron threaded smoothly onto the scope, the Antares chattered and squeaked a bit more so when being removed. 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. With spring galaxy season here, I decided to pick up a couple more to compare in a head-to-head shoot out. Celestrons aplanatic EdgeHD optics revolutionized astroimaging. 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"). Copyright 2003-2022 Agena AstroProducts. 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). 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. You attach the focal reducer to the rear port on a SCT and can keep it covered. This article explains the basics of how focal reducers work with an astronomy telescope. Possibly the design of the Antares was changed .. These reducers can also be used for visual observing with SCT scopes with eyepieces with a field stop as large as 24-27mm. It also leads to larger (although fainter) images of extended objects like the Moon or planets for astrophotographers or visual observers. If the focal reducer is to be used for visual observation, the visual back is threaded onto the eyepiece side of the reducer, and then a star diagonal and eyepiece are installed as usual. The most popular accessories for your new telescope! In such cases, we will be happy to take the item back as per our standard return terms. Who cares? 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. To further factor out my natural astigmatism (I normally wear glasses while observing), I did the tests with my regular progressive lenses, single vision glasses I use when observing, and naked eye. In many cases, the answer is yes, especially for electronically-assisted astronomy (EAA). ED glass is specially formulated and contains rare-earth compounds that greatly reduce a visual defect called chromatic aberration. Unlike . We will match any online price that we confirm as valid. It's easy! GSO, for example, has a 0.75x reducer for RC scopes with a back focus of 80mm, which is usually enough room for a wide range of astronomy cameras and accessories and spacers as needed. Photographically you also get a wider field and much shorter exposures. 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. Try & buy if you like - usual mates rates. These scopes are compatibles with focal reducers. Besides observing from his heavily light polluted backyard in Los Angeles, Manish enjoys conducting astronomy outreach programs in local schools. Reducer Lens .7x - EdgeHD 925 Manish holds a Master's degree in Electrical Engineering from Virginia Tech and an MBA from the Kellogg School of Management at Northwestern University.
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