scopemobile
Member
Posts: 99
home town/country: Glasgow/Scotland
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Post by scopemobile on Jan 17, 2019 22:53:59 GMT
I've been pottering about on the sidelines (mechanical) and have noted a few posts on the big astro sites about meridian flip and solutions to it, from belt drive mods to purchasing expensive high end precision mounts which seem to do the trick I've had a wee spark of an idea and put a name to it - EQUATORIAL MOUNT BACKLASH REDUCTION ATTACHMENT this idea might help in the problem of the OTA going OTT and kicking in the Meridian flip which messes up the long exposure times of the A P people . I think the VA squad are slightly immune to M/F due to their mobility on the scope.
This project requires me making a test rig, and a few sub assembles are on the go. Davy nephew has located a couple of ford flywheels with shrink on ring gears and his boss at the garage has sourced bendix gearing to match the old flywheels
The guys at the garage are having a good laugh, saying the mount will need a commercial truck starter motor to drive it, with all the weight I'am putting on it. (Instead of 12V stepper motors).
A pedestal is the next operation, then ALT. Adjustment on the base of the mount, this has motor bike chain and sprocket mechanism to get away from the jacking screw method which is possible prone to bending.
If the test rig is a failure, the pedestal can be used as a bird feeder/pot plant holder I can imagine the boss saying - "that monstrosity in my garden - no way........!.
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Post by howie1 on Jan 18, 2019 0:13:30 GMT
I've been pottering about on the sidelines (mechanical) and have noted a few posts on the big astro sites about meridian flip and solutions to it, from belt drive mods to purchasing expensive high end precision mounts which seem to do the trick I've had a wee spark of an idea and put a name to it - EQUATORIAL MOUNT BACKLASH REDUCTION ATTACHMENT this idea might help in the problem of the OTA going OTT and kicking in the Meridian flip which messes up the long exposure times of the A P people . I think the VA squad are slightly immune to M/F due to their mobility on the scope. This project requires me making a test rig, and a few sub assembles are on the go. Davy nephew has located a couple of ford flywheels with shrink on ring gears and his boss at the garage has sourced bendix gearing to match the old flywheels The guys at the garage are having a good laugh, saying the mount will need a commercial truck starter motor to drive it, with all the weight I'am putting on it. (Instead of 12V stepper motors). A pedestal is the next operation, then ALT. Adjustment on the base of the mount, this has motor bike chain and sprocket mechanism to get away from the jacking screw method which is possible prone to bending. If the test rig is a failure, the pedestal can be used as a bird feeder/pot plant holder I can imagine the boss saying - "that monstrosity in my garden - no way........!. Be interesting to see when you finish it. In the meantime (and maybe provide inspiration) the Avalon M-Uno mount doesn't have any problems with meridian flip at all ... but costs nearly $US8,000 ! Ouch www.avalon-instruments.com/products/m-uno-equatorial-mount
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Post by Dragon Man on Jan 18, 2019 13:05:03 GMT
Interesting idea John! I'm always amazed when I read about people complaining about Meridian flip on their mounts. My old black model Skywatcher EQ6 doesn't have meridian flip. It happily sails along all night crossing the meridian when fixed onto an object. I have even tested it in the past by leaving it running all night from east to west to see what it would do. It did nothing, just kept on tracking. But my hand controller is the old v2.05a which may not have had Meridian Flip written into its software.
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scopemobile
Member
Posts: 99
home town/country: Glasgow/Scotland
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Post by scopemobile on Jan 18, 2019 15:38:23 GMT
thanks howie and ken for the feedback, that avalon mount looks the part, the design skills must percolate through from their motor industry,ferrari and maserati. in the , the 60's , the factory i worked in had an innocenti boring machine, very large and innovative ,20 years ahead of its time. ken, the secret to your mount is the perfect balmy weather in the southern hemisphere, the heat expands the different metals so they allign and fit perfectly, no backlash, no problem. [smiley]
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Post by davy on Jan 19, 2019 7:01:17 GMT
Very true unc, these days it's all about the shiny new state of the art toys,, a company brings out a new camera ect,and the ,,, I've got to have it folk,, jump right in and buy it,, because it's new. But guys no kidding the couple of old flywheels I sourced were about 50 yrs old, weighing a fair bit,,but couple of weeks later,, the finished article unc brought in kinda left a few of us in the garage with the jaw on the floor look.
Cracking bit of engineering,, cut away sections of its mass by hand and filed up looking brilliant,, Still think timing belt and cog's are better than meshing gears to reduce backlash, and quieter,, But,, this will be a cracking mount when made,, not doubting it for a second.
I've sourced 3d printed brackets for nema drive motor's and can make prototype if required to suit mount,, will reduce some weight at least 😂
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Post by davy on Jan 19, 2019 7:05:01 GMT
I've been pottering about on the sidelines (mechanical) and have noted a few posts on the big astro sites about meridian flip and solutions to it, from belt drive mods to purchasing expensive high end precision mounts which seem to do the trick I've had a wee spark of an idea and put a name to it - EQUATORIAL MOUNT BACKLASH REDUCTION ATTACHMENT this idea might help in the problem of the OTA going OTT and kicking in the Meridian flip which messes up the long exposure times of the A P people . I think the VA squad are slightly immune to M/F due to their mobility on the scope. This project requires me making a test rig, and a few sub assembles are on the go. Davy nephew has located a couple of ford flywheels with shrink on ring gears and his  boss at the garage has sourced bendix gearing to match the old flywheels The guys at the garage are having a good laugh, saying the mount will need a commercial truck starter motor to drive it, with all the weight I'am putting on it. (Instead of 12V stepper motors). A pedestal is the next operation, then ALT. Adjustment on the base of the mount, this has motor bike chain and sprocket mechanism to get away from the jacking screw method which is possible prone to bending. If the test rig is a failure, the pedestal can be used as a bird feeder/pot plant holder I can imagine the boss saying - "that monstrosity in my garden - no way........!. Be interesting to see when you finish it. In the meantime (and maybe provide inspiration) the Avalon M-Uno mount doesn't have any problems with meridian flip at all ... but costs nearly $US8,000 ! Ouch www.avalon-instruments.com/products/m-uno-equatorial-mountDon't feel sorry for him Howie,, uncle John has an eq8 sitting in the house,, 😀
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Post by davy on Jan 19, 2019 7:14:40 GMT
On the subject of building.. machines,, The jumps in 3d printing technology in last year has been interesting to watch,, how long will it be before we see big machines metal printing,,
My boss broke an attachment part on his shower door,, tried gluing it with various stuff to no avail... He heard me taking about 3d printing and asked if I could make one,, took me 2.5hrs on cad software to get the shape pretty close and 2.5 hours printing,, never thought it possible but I got it and boss was delighted,, no grief from his Mrs and not having to buy a new bathroom suite... P.s Don't think his Mrs was impressed,, she lost out on a new bathroom suite 😂😂😂
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Post by howie1 on Jan 20, 2019 1:53:51 GMT
Actually, just thinking about meridian flip etc ... and thinking about my post on that uber expensive Avalon mount ... that mount will not actually get rid of the reason of all the problems on the meridian!
How come?
Well, I could be wrong, but I think the reason meridian flips were designed into the tracking systems of EQ mounts was the fear that the focuser end of the OTA might impact on the front leg of the tripod as it goes very low and close to that front leg when the optics are pointing up near the Meridian. Plus flipping on the Meridian also, importantly, gets around mirror flop which occurs in SCT's and Newts as it "falls" over due to gravity as it goes through the Meridian. So looking at that uber $ Avalon mount, it gets around the problem of the closeness of the focuser to the front leg by placing the OTA well forward on the RA axis. So far forward that it is very unlikely any part of the focuser end of the OTA is anywhere near making contact with that front leg. But, if you think about it, that Avalon design would still not get around mirror flop in both SCT's and Newtonians! As those OTA's go past the meridian, even on the Uno Avalon, gravity will still do its thing ... and the mirror will "flop" at that point from one side to another ... and you'll still get mirror flop optical aberations.
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Post by davy on Jan 20, 2019 6:01:11 GMT
Good point on tripod or mount design howie, I don't really come across this very often and in fact I think it only happened once with me ,, the mount doing a meridian flip.. I thought the mount had went bonkers,,, My ota had came close to coming a cropper one day,, as you said focuser and camera going to hit one of the heq5 legs,,, broke out in a cold sweat when I thought how much damage and cost that would have cost me. That was the primary reason to purchase the heq5 tripod extension mount ,, OK it was expensive but cheaper than damaging kit,, still comes close at times depending on scope and kit on focuser end.
Wonder if a large gyroscope type mount would overcome a lot of issues ,, but would need scopes with mirror lock.
Wonder how long it will be before someone has a go at fixing micro motor's to a mirror cell to compensate for flips and focus via software for amateur astronomers
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Post by Dragon Man on Jan 20, 2019 6:55:32 GMT
Mine hit the tripod leg once, and only once because after that incident I fitted the EQ6 extension kit When it hit, the mount started to beep. Bit late
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Post by ChrisV on Jan 21, 2019 6:20:06 GMT
Ouch. Would a pier avoid the problem?
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Post by Dragon Man on Jan 21, 2019 8:48:27 GMT
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Post by davy on Jan 21, 2019 13:23:26 GMT
Fancied one of these for flat to reduce the footprint of the tripod
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