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Re: Pier side
Jamie,
Make sure your Go To Limit allows you to point to items a bit east of the meridian with the scope on the east side.? For example, if your east and west limits are each 100 degrees, you can set your go to limit at 15 degrees (which is 5 degrees before the meridian).? That will let the go to command in EKOS point at anything with an hour angle greater than -20 minutes with the scope on the east side.? This setting will also ensure that a meridian flip can occur anytime the pointing position is beyond this limit. RD Beck |
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Re: Gemini-2 momentarily went haywire
¿ªÔÆÌåÓýUpdate ¨C I¡¯ve actually replaced three of those H-Bridges ? D. ? From: [email protected] <[email protected]> On Behalf Of Brendan Smith ? John I thought I saw some bubbling on the U7 IC but it looks to be just the glue/lacquer Losmandy/Aveox used to glue down the firmware sticker on the DSPIC. |
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Roadside Treasure will be a Counterweight
My wife & I took a drive along the Oregon coast last weekend. We stopped at a turn-out near Gold beach. And there Renee' noticed a real treasure laying on the gravel - a cylinder of steel about 6-inch diameter and 2 inches thick. With a suitable hole drilled in the middle this will make a nice counterweight for my G11 mount. As is, it weighs a bit over 17 lbs. (8 kg.). I'm thinking of having a machine shop drill the hole. I could make a radial, threaded hole for a bolt to secure it to the counterweight shaft. But lacking that, it could be use at the end of the shaft, up against the toe-guard washer. Then balancing could be achieved by positioning some other weights above my home-grown weight. Someone's junk is another's treasure. A little machine work and paint will make another usable counterweight.
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Pier side
With my backyard view it's best if I can have the scope hang to the east to start the night. I use kstars/ekos/indi connected to skysafari to select and slew to a target. It usually seems to end up with the scope hanging west. I usually have to use the manual control in skysafari to position it close to the target, and then slew to it. I'm assuming that scope position is determined by my GeminiII system on the GM811G (couple years old). Is there a setting to prefer positioning the scope to the east??
Jamie |
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Re: Gemini-2 momentarily went haywire
Ceramic cores are fine if properly sized for the application but at very low frequencies the core would not be very effective plus the core would be large and heavy. ?See the ARRL RFI handbook. ? If possible first measure the noise on the DC motor circuit with an Oscilloscope, maybe one of your ham radio or techy friends has one. ?A ?.1mfd ceramic disc capacitor (dot 1 mfd) rated at anything above 50 volts at the dc connection to the motor DC terminals. ?$0.10 . ? ?I have remote controlled DC motors with various decoders not only in my Astro gear but ham radio antenna rotators and WiFi controlled antenna tuners to suppress motor noise. ? Ceramic Ferrite Cores with sufficient inductance would be too large and heavy and are more effective to suppress high frequency noise. ? ?
It would not hurt to add a large filter capacitor across the DC plug to smooth out voltage drop due to motor start surge current . ?Some people have mentioned replacing the power supply but I wonder if that is really necessary , large current surge can be ¡®smoothed¡¯ out with a properly sized electrolytic capacitor across the DC line, such a capacitor is in every power supply ever made , 1000mfd at 50 volts ?but again I like to see the circuit on an oscilloscope for a before and after picture but Non of these components would harm anything ... ceramic disc capacitors are not polarized +/- but Electrolytic capacitors are Polar sensitive, the terminals are marked positive and negative so pay attention to connect positive to positive and negative to negative. ? ? ? ? Of course proceed at your own risk, all mentioned components are common electronic parts, The electrolytic can be installed anywhere along the DC cable or at a connector just remember positive to positive, negative to negative, thevalue is not critical but the voltage rating should be at least 3 times the power supply output for safety so 35volt or higher rating is Ok, ?The ceramic disc capacitor is very small and should be at the motor terminals. ?A 15 watt soldering iron is best for the job, not 100 watts which could destroy parts. ?? |
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Re: Reducing DEC Backlash with Titan 50
Dan, Some notes on adjusting the worm on a Titan vs G11 or GM8 1. The G11 and GM8 use individual worm bearing blocks.? Each block has a bottom "nipple" that fits a specific hole.? The left hole, closest the gearbox, is a pivot point.? You simply pivot the worm into the ring gear using the pivot point, feel for free worm tightness, then tighten down the worm blocks....done. Then you adjust the gearbox until the Oldham coupler plastic center just rotates, not shifts.? Then attach the motor...done.?? 2. The Titan has no pivot point.? Both mounting bolts can swivel and pivot so the worm can shift left or right.? The length of the worm enclosure block is larger than the plate on which it mounts. You must therefore rest the worm in its enclosure on top of the ring gear, and perhaps use a level, and feel the ends to see if your block is nearly centered.? ? Fortunately, if your Titan has tucked motors, the entire drive gear assembly is bolted directly to the worm enclosure.? You can tilt or shift the week RM and not affect the drive gear train at all.?? Some owners have used automotive feeler gauges to measure the gap on either end of the worm block, to see if it is level.? You'd need two sets of feeler gauges and the gap will be thick.?? When you have the worm block assembled don't completely tighten the 14mm nuts that hold the worm block down.? You can use the upper Allen head bolts to pull the worm block up off of the worm if it has too much friction.?? It is best to have an ammeter equipped power supply to the Gemini, to tell the Gemini motor current.? Then you can determine the gear adjustments that give consistently low motor current. (If you need one, contact me separately).? ---- other related adjustments ---- As I mentioned in an earlier post, one problem area is the worm can have a lateral shift, or be pressed too tight leading to worm friction.? On the OVision worm block for the G11, they used a Belleville spring washer under the end cap screw.? Losmandy doesn't use one but I think that's a best approach. The spring size to use is for a 6200 size bearing.? You put the outer cup edge forcing into the worm bearing OD, and let the inner cup edge go against the threaded endcap.? I use two such Belleville washers inner cup to inner cup.? Then just screw in the end so until the Belleville washer(s) and worm bearing are in contact and turn another 1/8 turn.? Finally (?) I find the worm to ring gear grease is also important.? You want the lowest friction possible because the worm has to rub nearly perpendicular to the ring gear.? This action is like the bowing of a violin string, and can lead to a vibration ("chatter").? The lube with lowest "4-ball test mark distance" of 0.6mm, and highest Timken test rating of 60 lbs is the CRC Brake and Caliper Grease.? This gave the smoothest performance to my G11T titan RA drive.? That lube has anticorrosion ingredients and the same low copper corrosion behavior as Super lube.? But it seems to stays in the metal to metal high pressure contact point of the worm to ring gear better than superlube. ?Best of luck, Michael On Mon, May 10, 2021, 11:40 AM dkfcpalfd via <dkfcpalfd=[email protected]> wrote: Thanks to you both.? Very informative.?? |
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Re: Still some DEC issues
On Tue, May 11, 2021 at 05:54 AM, alan137 wrote:
Is there a way to trim the guide log?? Do I post it here or some other place?? Because SOME people who complain about getting a second message from editing probably don't want to get a several hundred kilobyte file that they aren't going to look at anyway.Use a Zip utility to compress the log file and upload it to the Files section here:?/g/Losmandy_users/files?and then post a link to it in a message. Don't send it out as an attachment to your message, unless it's a small file. Regards, ? ? ?-Paul |
Richard Beck
David C. Partridge
Russell Milton
Jamie Amendolagine
Chip Louie
Bill P.
Michael Herman
Paul Kanevsky