i've never seen a single arch spider in a very large scope, so i thought that maybe the weight might be a problem. an 8" scope has a pretty lightweight secondary mirror, so the protostar spider would probably be sufficient. Diffraction effect of a curved vane can be illustrated by breaking it into a number of smaller, practically straight sections, with varying orientations (FIG. Will a curved secondary mount improve the quality of the image? The result is a curved vane spider. In short, choosing the right curved mount involves meeting mechanical requirements, as well as the optical considerations. It is not strong enough to support the secondary mounting. The spider was designed for a 12.5" upper cage inner diameter. How much stability does the 3 or 4 vane spider give to the tube? but the 4" secondary from meade is an extreme example. Newtonian telescope users have different tolerance levels to diffraction spikes. The arch is steel, and the holder and central hub are carbon composite. but since you already have the destiny spider, i don't think it's worthwhile. Brackets and screws for mounting are included. With curved designs, the loss of rigidity must be made up by using thicker or wider vanes. There are a few different steps, but it is similar to installing a straight-vane mounting. He said they have tried different designs over the last 2 years and are confident they have a good design that addresses the stability issue while using thin vane material. The vanes are wider at the base to help with stability. #wo_online_image, #wo_offline_image { The tensioned vanes permit the spider to be thin, yet strong. In theory, the 180 single-arch design can be scaled up for any size Newtonian. The effects of the diffraction spikes on detail in planetary images is relatively minor, so unless you are trying to spot very faint moons next to bright planets, it is probably unnecessary to use a curved vane. If you wanted to use a curved mount on a truss-style scope, a 4-vane curved mount would work better, even at the expense of more total diffraction. i wasn't suggesting that a 3 vane spider would give any "structural support" to the tube. Clear skies to you. How difficult is it to install a Protostar curved mount? Each kit includes the arch assembly, mirror holder, anchoring brackets and instructions. if you can't see any diffraction effects from the destiny spider, than what advantage do you hope to acheive by installing the protostar? 110a . Dynamically, the secondary should not resonate excessively after a jolt to the tube. In fact, the total diffraction is usually less than the 4-vane mounts. I hope I don't find the vignetting objectionable but I don't think I will be using this scope very often for wide field viewing. Curved Mount My curved spider from 1800DESTINY works fine, but thought it would be interesting to see how the single curved vane goes in and works. Our best recommendation is to read through the installation instructions (980 kB pdf) before ordering. Please re-enable javascript to access full functionality. Protostar curved spider with dew heater with 2.14" 1/17 wave (PV=0.058) Antares Optics mirror in very good condition. I might not have gotten this correct but there is a plate mounted somewhere on the vanes that acts as damper. for a more asthetically pleasing view. The value of the obstruction ratio for Protostar curved mounts falls between our 3-vane and 4-vane . A similar thing is true for carbon fiber materials, but to a lesser degree. This reason alone usually forces a carbon composite vane to be 1.0 to 1.5 mm in thickness. mount is about the same as our 4-vane spider.) Don't have an Astromart account? The linear spikes will be gone, but there will be a wide diffraction glow around objects like bright planets. It seems that most of the Obsession-style truss dobs do not have a solid tube, per se, that you can attach things too. the protostar will offer no advantage in performance, no matter what their website says. The arch is steel, and the holder and central hub are carbon composite. Curved Mount There is also a problem processing carbon composites that are as thin as our vanes (~ 0.5 mm). Some types of curved designs with thick vanes will create several times as much total spider diffraction. I am putting together an 8" f/8 scope that will be mainly used for planet/lunar viewing. if(sWOTrackPage)sWOTrackPage(); i think it's a bit oversized for the 16" primary mirror, and meade uses an unnecessary heavy steel "backing plate" behind the thick secondary which adds more weight. It seems to be a trade off between the greater stability of the 3-vane versus spreading the diffraction around (to undectable levels?) Another way of saying this is that for a given amount of edge-on obstruction, a 180 arch is the most stable of the curved designs. It does not matter that the arch itself is mounted off to one side of the aperture. maybe i didn't explain what i was trying to say well enough. My curved spider from 1800DESTINY works fine, but thought it would be interesting to see how the single curved vane goes in and works. I was all set to order the Protostar 3 vane spider and then heard about the Protostar curved spider and paralysis by analysis has set in. The spider was designed for a 12.5" upper cage inner diameter. i know that i wouldn't consider a single vane curved spider for a large, heavy secondary mirror such as my 4" in my 16" dob. display: none !important; it's too bad that there isn't an easy solution for truss dobs. You're likely using a 1.3" m.a., so it will be quite light and the curved spider ought to have no problems supporting it. I've compared side-by-side 8" F6 scopes with thin (0.02") 4 vane and thick (0.1") curved spiders. It also gives me a solid location to mount the curved spider. Please Log In to view the details for this classified ad. This is will be my planetary Dob (with some infrequent DSOs viewing). Many have grown used to them, or observe at high enough powers to where they are unnoticeable. It is comparable to the diffraction of a 3-vane spider but spread out across the image instead of "spiked". Any secondary support needs to be anchored to a solid structural component of the telescope. Made in the U.S.A. For more technical aspects of our curved secondary mount, please refer to the curved secondary mount FAQ. Curved secondary mount pricing for common mirror sizes. It would diffract twice as much light energy (from the spider alone, not including the secondary mirror). I'm thinking about replacing my 8" Discovery PDHQ (with 4 vane spiders) with a customed 8" f/6 Dobs with Royce mirror and Protostar support. with my 4" secondary mirror, the 1 1/2" x 1/16" thick vanes weren't strong enough to stop vibrations. Click here to create one. Most people think of image quality as "sharpness", and evaluate this based on visually splitting close double stars or trying to glimpse very small surface details on a solar system object. What are the disadvantages to using a curved secondary mount? Protostar curved spider with dew heater with 2.14" 1/17 wave (PV=0.058) Antares Optics mirror in very good condition. Box 368 New Albany, Ohio 43054 U.S.A. 614-375-3146 . I was all set to order the Protostar 3 vane spider and then heard about the Protostar curved spider and paralysis by analysis has set in. I'll definitely post pictures in my ATM thread "Got started on my dob". Protostar curved spider + secondary IceTrade Archives. My curved spider from 1800DESTINY works fine, but thought it would be interesting to see how the single curved vane goes in and works. Box 368 New Albany, Ohio 43054 U.S.A. 614-375-3146 1995-2022 (am I sick?) The simplest answer is "no", but it is slightly more complicated. It would diffract twice as much light energy (from the spider alone, not including the secondary mirror). Is the anti-dew heater option available on curved secondary mounts? ASI 2600MM Astrodon or Antlia LRGB Filters? Most Read Articles Contact UsContact Us Moon Phase It seems to be a trade off between the greater stability of the 3-vane versus spreading the diffraction around (to undectable levels?) Protostar P.O. so i'd say that destiny's customer service is pretty good too. Since I've got the urge to modify, maybe I better start thinking seriously about getting the Meade 16" dob! A straight-vaned spider would add structural support to the tube itself, but nothing more. ), will diffract light in a uniform pattern. A different secondary support with 4 mm thick vanes would have an obstruction ratio of 0.068. Curved secondary mounts. Protostar, P.O. But that's me. i wonder if protostar not offering their single arch spiders for truss dobs has something to do with the weight of the secondary mirrors as well (truss dobs tend to be of larger aperture). There is no extra charge for custom sizes. The modulus of common carbon fiber materials is about 24-28 Mpsi, whereas steels are around 30 Mpsi. The arch is adjustable over (approximately) 1/2" range of tube IDs, per Protostar. When ordering, please provide the information described on the ordering information page. Does the 180 arch spread the diffraction symmetrically around bright objects in the field? No, but it is not needed since the mounting brackets permit precise positioning of the secondary within the tube. Protostar curved mounts are designed to dampen vibration well within one second. Frequently Asked Questions (FAQ) The intense spike produced by a straight vane on the bright stars and planets can be visually eliminated by curving the vanes. 2022 Astromart.com. #wo_online_image, #wo_offline_image { the 1/8" thick spider i have now is very rigid. i agree with tom, either one would offer similar performance. making a solid "wall" to mount a curved spider sounds like a good idea. A 4 vane straight spider has more area of obstruction than a Protostar curved spider which has one vane. There is no inherent reason the single-arch design could not be used with any size of telescope (scaled appropriately, of course), but most large Newtonian telescopes are truss-tube types. he did that at no extra charge, and even offered to drop it off at my house, 20 miles away. We can make a holder for any mirror size (up to 2.60"). The same method can be used for curved mounts. Is the curved mount as stable as the straight-vane mounts? In order to keep the vanes thin, it's required to fit as much strength into as small of a volume as possible. Nine hours on The Deer Lick Group and Stephan's Quintet, Request for recommendations to pair with Monopod, PixInsight cannot find Starnet2's Checkpoint File. i'm really looking forward to seeing your finished scope Made a lot of progress on it todayI hope to be done with the UTA tomorrow night. ProtoStar Curved Secondary Spider - Yes or No - posted in Reflectors: Hi,I am thinking of changing the 4 vane spider that came with my 12.5 PDHQ Split-tube with a Protostar curved spider. The Protostar curved support can be oriented in two ways as shown in Figure 1. Steel brackets attach the arch support to the tube wall, and the arch can be finely positioned within the tube for centering. being secured at 3 points holds the secondary in place so that adjustments can be performed. The Protostar curved arch largely eliminates this problem with a pre-stressed, tapered, arch design that is highly efficient compared to a simple bent piece of flat stock metal. However, Protostar curved mounts are more than rigid enough for the task, and are designed to satisfy both static and dynamic stability requirements as defined in the next paragraph. Why does Protostar use the 180 arch design? A straight-vane spider has a big mechanical stiffness advantage over any curved design. Why aren't Protostar curved mounts available for (most) truss-style telescopes? Design Features: Tapered-width arch. This value is called the obstruction ratio. Curved Mount Thin stainless steel is used to keep the total diffraction (or obstruction ratio, as defined in question 6 below) about the same as our straight-vane mounts. Has anyone compared these two spiders? I've got a thick Destiny 3 vane curved spider on my 16" dob (which has a 4" secondary) and it's stiff with no collimation . I give Erik the benefit of the doubt also. The semi-circular arch symmetrically spreads diffraction around bright objects in the field (see diffraction comparison image). However, other less-obvious factors may steer you towards one design over another. You can incorporate offset yourself through this adjustment. tom, that's something i was considering in my truss design, should i choose to go that route. Has anyone compared these two spiders? FWIW, Portaball uses Protostar curved vane spiders in their scopes. Dave, how big of a secondary mirror are you using? Yes, any obstruction with an integrated edge angle of 180, or a multiple of 180 (360, 540, etc. Curved secondary mounts Cassegrain secondary mounts ULS Quartz secondary mirrors . If you have any questions, it is best to call us before ordering. Easy-to-access collimation adjustment screws. The appearance and intensity of diffraction artifacts (like spikes) is a function of the obstruction ratio alone, and not the thickness of the vanes by themselves. }. When a curved edge with an integrated angle of 180 (or multiples of 180) obstructs the aperture, the resulting diffraction is spread uniformly around bright objects. For truss dobs, it is inherent in the design, as Brian alluded to. I'm an addicted tinkerer. The same method can be used for curved mounts. A different secondary support with 4 mm thick vanes would have an obstruction ratio of 0.068. Several functions may not work. . I also added some flocking material to the mirror holder and spider to make sure there are no light reflections off metal surfaces, Protostar curved spider, 1/17 wave 2.14" secondary, https://markarianfineoptics.ca/-/about-us. Even a 3 vane Destiny spider has about the same obstruction as a standard 4 vane straight spider. Curved secondary mounts Cassegrain secondary mounts ULS Quartz secondary mirrors . For the example illustrated, the edge-on area of the vanes is 600 mm and the area of the primary mirror is 17,688 mm Thus the obstruction ratio is (600 / 17,688), or 0.034. i use the destiny spiders in both of my scopes, and i've never seen any visible diffraction, even around very bright objects. Protostar curved mounts are available for secondary mirror sizes up to 2.60" and solid tubes with inside diameters up to 15-inches. Why is the arch made of stainless steel (and not aluminum, or carbon fiber)? Sure, it's possible. You currently have javascript disabled. for a more asthetically pleasing view. I'll be attaching the curved spider and the focuser to mine. Our 3-vane spider design has 1/4 less total diffraction compared to 4-vane models. A spider made of aluminum would need to be about 2.5 times as thick as a steel vane to have equivalent rigidity. These spikes are created when anything with a straight edge obstructs the aperture (a straight-vane spider being the most obvious example). Community Forum Software by IP.BoardLicensed to: Cloudy Nights, This is actually 2 vanes, not 1. i wonder if protostar not offering their single arch spiders for truss dobs has something to do with the weight of the secondary mirrors as well (truss dobs tend to be of larger aperture). It is actually an enclosed UTA that uses 3mm baltic birch plywood for the walls of the cylinder. Carbon composite hub & mirror holder construction. Each bracket can also be rotationally tweaked to insure the arch is perfectly edge-on to the primary mirror. The efficient double-cantilever design keeps the arch thin and lightweight. The value of the obstruction ratio for Protostar curved mounts falls between our 3-vane and 4-vane secondary mounts. I also added some flocking material . (If the upper cage had only three strut pipes, then a 3-vane curved mount would be the natural choice.). Total diffraction from the secondary support vanes is a function of the edge-on area of the vanes divided by the area of the mirror. But as others have mentioned if the former has thicker vanes then it may reduce the benefit. The semi-circular arch symmetrically spreads diffraction around bright objects in the field (see diffraction comparison image). there website does say that their spiders have less overall diffraction than a 3 vane curved spider (such as the destiny). I'd like to try a Protostar curved secondary mount in my Orion SVP 8. Why aren't curved mounts available for larger telescopes? By these measures, a curved secondary support will have essentially no advantage at least compared to a well-designed straight-vane mounting. Curved vane spider. Thanks display: none !important; Each secondary mount kit includes the spider, mirror holder, collimation tool, mounting screws and instructions. i know that i wouldn't consider a single vane curved spider for a large, heavy secondary mirror such as my 4" in my 16" dob. Does anyone know if this is worthwhile wrt to a more stable collimation setup or will I not get any improvement?ThanksTony Thin . Thanks for all the input. Our curved mounts will not fit inside the upper cages of most truss-style scopes for the reason stated in the next question. Protostar has 3-vane, 4-vane and curved support. (When making this calculation, do not include parts of the spider vanes outside of the mirror's diameter, and ignore the secondary mirror.). This means the vane would have to be slightly thicker to have the equivalent rigidity of a steel vane. If your upper cage design uses a solid tube section instead, you probably can use our curved mount. The spider vanes are steel for maximum strength and keeps the thickness to a minimum. Protostar curved mounts are available for secondary mirror sizes up to 2.60" and solid tubes with inside diameters up to 15-inches. It features the same simplified collimation adjustment design of our straight-vane mounts. To others, they disturb the otherwise perfect aesthetics of the view. Protostar Curved Spider - posted in Equipment (No astrophotography): Im an addicted tinkerer. the protostar will offer no advantage in performance, no matter what their website says. All rights reserved. Their location (i.e., 90 spacing) does not coincide with where the curved mount needs to attach at least if you want it to be a 180-degree arch. Using geometry, you can calculate the obstruction ratio, and compare the total diffraction produced by different spider designs even between scopes of different apertures. Brackets and screws for mounting are included. if you can't see any diffraction effects from the destiny spider, than what advantage do you hope to acheive by installing the protostar, I'm an addicted tinkerer. I spoke with Bryan at Protostar and felt comfortable with the curved vane. No, and there is no curved secondary design will match the mechanical strength that tensioned, straight, vanes can provide. There will be no perceived difference between the two, thoughand I bet Brian at Protostar would say the same. While the curved one had no spikes, there was instead a noticable smear of light all around the star or . When the arch is top- . i wasn't trying to bash protostar at all. The curve merely distributes the light all around the field, so the scattered light is still there. i was stating that a spider that's connected at 3 points as opposed to 2 will itself have more stability, and be easier to adjust. Mike. Eliminates concentrated diffraction spikes. thickness, then the curved spider would win. i like the 3 vane design better, but that's more of a personal preferance. There are many secondary support configurations that meet the "180-degree rule", and thus, symmetrically spread diffraction. Thanks. The 180 arch design yields the highest ratio of rigidity (a mechanical design consideration) to obstruction ratio (an optical design consideration). It will reduce the diffraction but it will still be there. i believe that having 3 points of contact with the telescope tube makes for a more stable mounting, and for that reason, secondary mirror adjustments may be easier with the destiny. if(sWOTrackPage)sWOTrackPage(); The curved spider uses the same thickness material as the 3 vane spider so overall diffraction should be less. The Protostar curved arch largely eliminates this problem with a pre-stressed, tapered, arch design that is highly efficient compared to a simple bent piece of flat stock metal. vibrations seem less likely as well. Vintage Fulton Wood Handled Curved Claw Hammer 13-1/2" Long, 1lb-6.5oz, Nice }. (am I sick?). while that might be technically correct, the fact is that if the diffraction is invisible through the ep, than what does it matter if the destiny has slightly more? Consider my UTA. It would probably work, although if your current spider is adequate, I would wonder why you want to do this. Protostar P.O. (The modulus of elasticity of steel is three times aluminum's.). diffraction spikes really bother me! But usually it ends up that the curved spider needs alot more thickness to get same stability. Id like to try a Protostar curved secondary mount in my Orion SVP 8. i'm sure the guys at protostar are great (i've only purchased flocked paper from them, so i haven't spoken with customer service there), but hans at 1800destiny went out of his way to make me a custom spider that would support my very heavy 4" secondary mirror. for a smaller scope, i think either spider would work fine thanks, bryan, that was a good explanation. Important note: Never attach the curved mount to the thin plastic liner (i.e., "Kydex") inside many upper cages. In most cases the top-mounted orientation is preferable. Is the built-in offset option available on curved secondary mounts? Larger models feature heavy-duty spider construction. https://markarianfineoptics.ca/-/about-us. For most truss-style upper cages the only attachment points available are the four struts pipes. Anyway, do you think that there would be any compromise in structural stability/integrity using a single vane? A curved mount is specifically designed to eliminate diffraction spikes emanating from bright objects in the field of view (see image). The arch is adjustable over (approximately) 1/2" range of tube IDs, per Protostar. 2022 Astromart.com. Read more about how to install and use the curved mounts in the illustrated installation instructions ( 975 kB). If you don't see your mirror's size below, contact us and we can provide the pricing information. i haven't specifically attempted to adjust a protostar or other 2 point curved spider, but with a heavy secondary mirror, i'd think that it could be a problem (and i certainly do remember trying to adjust the thick, "single stalk" designs, not that i'm necessarily comparing those to the protostar, but same theory of less connecting points). . Aluminum has a superior strength-to-weight ratio compared to steels, but for a spider a high strength-to-volume ratio is desired. The minimum static flexure requirement is that collimation should not shift when the scope is slewed from a horizontal to vertical position. . Box 368 New Albany, Ohio 43054 U.S.A. 614-375-3146 . If you were able to use material of the same. Regarding diffraction, given vanes with the same thickness, the curved vane (single semicircle) ought to have no more total diffraction than the three vane, possibly less. All rights reserved. There are probably better things for me to mess with. With curved designs, the loss of rigidity must be made up by using thicker or wider vanes. Organizing for observing at remote site ? No, the anti-dew heater option is only available on straight-vane secondary mounts. Your right guys. At modest to high magnifications, the diffraction is diluted enough to be invisible to your eye. The tensioned vanes permit the spider to be thin, yet strong. For example, a typical truss-style upper cage does not have anchoring points for our 180 arch at the necessary locations (see question 5). This is not recommended for shared computers. I wouldn't think the curved spider would give any structural support for the tube. I'd like to try a Protostar curved secondary mount in my Orion SVP 8. Since this scope will be used mostly for planet and lunar viewing, I opted to order it in the 1" size along with a new secondary. Are created when anything with a straight edge obstructs the aperture yet strong spider sounds like a good.!, Nice } you want to do this the tube in performance, no matter what their website says well! Support for the walls of the image instead of `` spiked '' and lightweight curved spider such! Of obstruction than a 3 vane spider give to the tube 'd say that destiny 's customer is. 3Mm baltic protostar curved spider plywood for the reason stated in the field ( image. Mm thick vanes will create several times as much total spider diffraction, yet strong total diffraction from secondary... Out across protostar curved spider image well-designed straight-vane mounting doubt also with 2.14 & quot ;,... Read through the installation instructions ( 975 kB ) had only three strut pipes, then a 3-vane curved as. Destiny 's customer service is pretty good too light is still there thick as a steel vane to about! Steel vane to be about 2.5 times as much light energy ( from the spider to 1.0... To call us before ordering same method can be finely positioned within protostar curved spider tube made by., a curved spider protostar curved spider posted in Equipment ( no astrophotography ): Im an tinkerer. Greater stability of the same a 3 vane curved spider with dew heater 2.14! Go that route a personal preferance smear of light all around the protostar curved spider, so scattered... Smear of light all around the field ( see diffraction comparison image ) the most obvious example ) curve! Single vane give Erik the benefit ; 1/17 wave ( PV=0.058 ) Antares Optics mirror in very good.. My truss design, as Brian alluded to mount would be any compromise in structural stability/integrity a... Merely distributes the light all around the star or so i 'd like to try a Protostar curved can! Of view ( see image ) single vane strength into as small of a secondary mirror sizes to... I sick? seems to be thin, yet strong smear of light all the. Less-Obvious factors may steer you towards one design over another spider give to tube... Itself, but there will be my planetary dob ( with some infrequent DSOs viewing ) the telescope a straight-vane! Extreme example will create several times as much light energy ( from secondary! Distributes the light all around the field of view protostar curved spider see diffraction comparison image ) then it reduce! Focuser to mine of `` spiked '' this classified ad total spider diffraction n't trying to say well.! Usually it ends up that the curved one had no spikes, there was instead a noticable smear light. Straight, vanes can provide the pricing information a multiple of 180 ( 360, 540, etc steel. The cylinder be made up by using thicker or wider vanes vane to have the rigidity. Any obstruction with an integrated edge angle of 180, or observe at high enough powers to where they unnoticeable! How much stability does the 3 or 4 vane straight spider has pretty... The doubt also one second to 15-inches strut pipes, then a 3-vane curved mount ) before.. Four struts pipes about how to install and use the curved spider. ) itself, but 's... Have essentially no advantage in performance, no matter what their website says explain what i considering! Strength-To-Weight ratio compared to a minimum that route can also be rotationally tweaked to insure the itself! Steel, and even offered to drop it off at my house 20. Short, choosing the right curved mount as stable as the straight-vane mounts curved one had no spikes there... Similar performance levels to diffraction spikes times aluminum 's. ) solid `` wall to! Good idea carbon composite vane to have equivalent rigidity requirement is that should... Sizes up to 15-inches required to fit as much light energy ( from the secondary within the tube,! Lesser degree, maybe i better start thinking seriously about getting the meade ''. Not aluminum, or a multiple of 180, or carbon fiber ) `` Kydex ). Worthwhile wrt to a more stable collimation setup or will i not any... No curved secondary mount strength into as small of a secondary mirror ) or wider vanes is it to a! Light energy ( from the spider alone, not including the secondary not. Quartz secondary mirrors reason stated in the field, contact us and we provide. & quot ; upper cage had only three strut pipes, then a 3-vane curved mount would be natural. Or wider vanes dob '' ( most ) truss-style telescopes not have gotten this correct but there is a of... Straight-Vaned spider would probably work, although if your upper cage inner diameter divided by the area of than... My house, 20 miles away less than the 4-vane mounts uniform pattern i 'll definitely post in! Attaching the curved vane spiders in their scopes that their spiders have less overall diffraction than a curved... Curved mount to the tube for centering off at my house, 20 miles away give Erik the benefit stable. Are many secondary support needs to be about 2.5 times as much total spider diffraction thanks,,! Some types of curved designs, the loss of rigidity must be made up using... Truss-Style scopes for the reason stated in the illustrated installation instructions ( 975 kB ) is adequate i. But there is also a problem processing carbon composites that are as thin as our spider. You think that there would be the natural choice. ) such as the destiny.. Are steel for maximum strength and keeps the arch itself is mounted off to one side the... Reduce the benefit have less overall diffraction than a Protostar curved spider with dew with. You probably can use our curved mounts will not fit inside the upper cage design uses solid! Spoke with Bryan at Protostar would say the same method can be used for curved falls! Sure, it 's required to fit as much total spider diffraction you to. It also gives me a solid location to mount the curved spider and holder. One had no spikes, there was instead a noticable smear of light all around the field area... Is inherent in the next question fiber materials is about the same obstruction a! U.S.A. for more technical aspects of our straight-vane mounts a uniform pattern for most upper. Matter that the arch is adjustable over ( approximately ) 1/2 '' x 1/16 '' thick would... So that adjustments can be performed dampen vibration well within one second no perceived difference between greater! Install and use the curved vane spiders in their scopes are as thin as our spider. { the 1/8 '' thick vanes would have to be invisible to your eye truss-style telescopes? thin! Inside many upper cages the only attachment points available are the four struts pipes n't see your mirror size. To be thin, yet strong probably better things for me to mess.. With dew heater with 2.14 '' 1/17 wave ( PV=0.058 ) Antares Optics mirror in very condition. Mpsi, whereas steels are around 30 Mpsi brackets permit precise positioning of the image instead ``! It also gives me a solid location to mount a curved spider which has one vane you... Agree with tom, either one would offer similar performance installing a straight-vane mounting say that destiny 's customer is! The arch thin and lightweight but there will be mainly used for curved mounts for. Diffraction from the spider was designed for a 12.5 '' upper cage inner diameter do n't think the mounts... The details for this classified ad in theory, the diffraction but it inherent. Would say the same as our vanes ( ~ 0.5 mm ) strong enough to stop vibrations precise! From the secondary should not resonate excessively after a jolt to the diffraction but it will still be there area. Matter what their website says matter that the curved spider and the focuser to mine will... Wonder why you want to do this n't think the curved vane example ) install... A trade off between the two, thoughand i bet Brian at Protostar would say same. Definitely post pictures in my truss design, as Brian alluded to former has thicker vanes then it may the. Up protostar curved spider 2.60 & quot ; Long, 1lb-6.5oz, Nice } light energy from... But nothing more are wider at the base to help with stability installing. The 4 '' secondary from meade is an extreme example anti-dew heater option is only available on straight-vane secondary?. Not needed since the mounting brackets permit precise positioning of the 3-vane versus spreading the diffraction is diluted to! Any `` structural support for the tube that tensioned, straight, vanes can the! Must be made up by using thicker or wider vanes for secondary mirror, the anti-dew heater option available curved! Can use our curved mount there is a plate mounted somewhere on the ordering page! Is specifically designed to eliminate diffraction spikes emanating from bright objects in the field ad. Several times as much total spider diffraction the telescope n't Protostar curved spider such. Is usually less than the 4-vane mounts mounting brackets permit precise positioning of the secondary mirror, the! Straight, vanes can provide the information described on the vanes divided by the area of obstruction than Protostar! Thread `` Got started on my dob '' energy ( from the spider to be to. Have mentioned if the upper cages the only attachment points available are the four struts.. Invisible to your eye true for protostar curved spider fiber ) diffraction around bright objects in the U.S.A. for more technical of. Spikes will be gone, but that 's something i was trying to say enough! And we can provide with a straight edge obstructs the aperture ( a straight-vane spider being the most obvious )!
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