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Re: Almost a new owner....
Thank You Brian!
Not visual at all, really. I got into this sport to do imaging of Nebula, specifically. So although coming at it from a budget point of view, I bought my initial gear with Astrophotography as my first aim. I do have a "beginners set" of eyepieces, two Barlow's, and viewed Saturn and it's rings my first summer. Spectacular, BTW. I'm in Saugus, but originally grew up in Encino. So I sometimes refer to myself as "The Encino Man" ;^) I took a very long road to land here in Saugus, CA. I'll have to learn about Gemini, and how the Losmandy starts up, connects, and gets running. I use to mount my telescope and connect my cables (all bundled), then power up, open my programs (PHD2, Infinity, AFF2 focuser, NexRemote (virtual hand controller), and Stellarium). Usually Stellarium connected automatically through the Celestron Virtual remote. I suspect Stellarium will just need to connect through the ASCOM or Gemini 2. (Not too sure about the pathways my Windows computer takes, but I do get there. LOL) I'm betting Scott Losmandy has these things all figured out being as he has been at this near forever. I kind of got lost mining down about the Gemini 2 on the Losmandy site. Looks to be very straight forward and very well explained. Just have to do a step-by-step for initial start (Cold Start). I was going to ask about cold start, warm start, but I think I have that figured out now. Thanks to you mentioning it, and my curiosity and trying to find the answer myself. I'll be pouring over those and taking notes so I can avoid my usual trial and error, error, error.... Thanks Brian! A coupling program called connects my two computers so I can run everything outside, from inside, as if I was sitting at that station. Once I got it all working, it's been great! And I have a Micro USB card mounted in an auxiliary slot that I store my imaging to. That works great because I can pop the card out, mount it to an adapter and put it in a slot of my tower computer to process. |
Re: G11 survival kit
Hi Deric -?
Michael's post is pretty comprehensive to have your mount run for the next century my simpler list for the next few years is: spare batteries for the Gemini spare motor cables for RA and DEC (they don't often go bad but they can) complete set of allen wrenches that's about it for me Brian |
Re: G11 survival kit
Very good question! (Oh oh... Another lightning rod question... off the deep end I go.? Apologies again!? My first blunder of 2020!) ... survival...and maintenance... Firstly: The G11 mounts have been tested by Periodic Error ("PE") tests to get to as low as about 0.9 arcsec RMS.? Those used the new version "high precision brass" worm (these vary individually) and also had some slight mount mods (added a Belleville spring washer under the far end worm bearing).? Stock G11 mounts vary.? The stock Titan used to be stated to have PE below 2 arcsec, and that has twice the ring gear size of the G11.? That would translate to about 4 arcsec on a G11 (G11 has no stated PE spec).? So the basic mount design is capable of fabulous performance.? I think all G11 units should get under 2 arcsec RMS if properly tuned up. I'll talk about the issues below.? ? _____ Your question about "survival" then has to do with how to make adjustments, how to recognize what adjustments to make, and other maintenance issues that might some day arise.? Here is a list of common issues this group has encountered, though frankly many folks have never had any issues at all.? Your sensitivity to issues really depends on what optical equipment you are using... could be a light short refractor or long 65lb Newtonian... or a long FL SCT.? So here goes....? ______ Tools: To adjust the drive gears, required from time to time, you should have these tools: 1. US fractional sized hex key ("Allen") wrenches.? Get two types: ? ? ?a.? straight end (use these if you have straight-on access) ? ? ?b. ball end (these allow you to get to bolts where you have no straight-on access).? That occurs for the critical large bolts below the worm blocks mounting flange (on the GM8, those bolts are accessible at an angle, on the G11, it's tight from straight on) 2. Good lubricants for the needle bearings.?? ? ?a. WD-40 ? ?b. A lubricant recommend by many is the Superlube type with teflon.? ? ________ Maintenance: _______ Gemini units: The Gemini units have an internal "coin" battery, nominally 3 volts.? Keep a spare of the required size battery for replacement, about once per year or 2 years.?? Preventing Gemini damage: To prevent internal corrosion, protect the unit from weather (i.e. rain!) and to protect it from electrical shock (like lightning), just unplug it's power and comm lines when you are done using it.? I find it's ok to keep the motor cables plugged in if the system is enclosed or totally covered up. *** Label your motor cables and motor and Gemini connections ***? The connectors on the motor cables are round ("DIN") and have 6 pins and a "detent" metal notch.? But the pins are rather equally distributed around in a circle.? And the notch is not very deep. It has been know to happen that an owner forced a motor cable into the socket when it was mis-rotated.? ?If you were to mistakenly rotate the motor connection you will damage either the Gemini or the motor...costly repairs or costly replacement.? Easiest to use a label-maker and keep the connections very clear.? Also the DEC cable is longer than the RA cable, because the cable must travel around with the mount head.?? _______ Mount head parts: Pertains to?non-tucked motor type drives:??older G11 and all GM8 type designs (DEC axis of GM811): Of course, don't drop the mount head(!) and when transporting, be sure to protect the motor end that is only attached to the gearbox, if your G(11 or M811 or M8) if it is exposed. The newer tucked motor design protects the motor and gearbox by metal flanges. The plastic gearbox cases have been known to break.? The gearboxes do not break under normal operation.? You can force grease into the internal plastic gears from the motor shaft side, but these gearboxes do not come apart.? ?Of course, over decades, the plastic becomes brittle and can break down.?? Therefore, some folks recommend having a spare gearbox! (About $35?from Losmandy). That's inexpensive insurance. (On the strsight-out motor version, people have replaced the plastic gearbox with a metal precision one.? McLennan has a model that can be made to fit ...needs some handiwork to fit one in.? I've done this on one GM811, and plan to do that on a G11 and CG11, but those are still working great with the plastic gearboxes.) _____ AZ hold down bolts You will be using the AZ and Elevation adjusters to polar align your RA axis.? (Strongly advised to drift align... and the PHD2 software has a nice feature for this.) There are two side hold down, T handle top AZ bolts that clamp the mount vertical rotation axis.?? I find the mount gets too slack when I loosen my 2 bolts.? So I add in Belleville spring washers to adjustably take up the slack.? Adding these also needs slightly longer bolts.? Contact me off line if you want these parts.? I have caps in Red, Yellow, Black.? I find the colored ones help me in near darkness.? See attached photo of this mod.? _______ All G11, and GM8 and GM811 (and Titan) Clutch disks issues and options: The clutch disks are plastic donut shaped pads, and they gently couple the driven bottom plate (driven by the worm gear) to the upper plate (holding the scope if DEC or holding the DEC axis if RA).? These plastic stock pads were designed to slip, so that an observer could easily push the scope to see something desired, and then gently grab to be again driven by the RA worm clock drive.? But in our age of 8 deep sky imaging, or the real world of bumps, a slippery clutch is a troublesome hazard.? So...let's talk about the clutches... The clutch pads can wear out...but should not.? They fail (slipping, won't hold position) because oils eventually creep on to the flat surfaces from the lubricated bearings.? Once oils creep into that area of the flat clutch pad, capillary action pulls the oils across the whole surface.? They are cleanable.? You can rather easily (no scope or counter weights!) undo and bag the rear clutch knob and it's flat needle bearings, and flat race washers, and lift off the axis shaft. Then de-grease the clutch metal faces, and clean the plastic clutch pad. The clutch pad and mating surfaces might come clean with just isopropyl alcohol.? The clutch disk can be replaced by a new plastic one, but the problem will eventually recurr.? I make up a special clutch disk that resists water and oils, and has a higher friction than the slippery stock clutch disks.? If you are planning to image, these replacement pads will help protect against bumps and also reduce the rear knob force needed to lock the axes in position.?? _______ Degreasing and re-lubing the bearings: When replacing the clutch disks, this is a great time to re-lube all the internal needle bearings.? The needles are very thin hardened steel rods, and they are supposed to be oiled or greased to work properly. The needles should be free to revolve. When you pull out the 1.25 inch axis shaft, you can reach in to touch the top needle bearing rollers. See if they are moving easily or are gummed up.?? ?If (when) old lubricant loses its fluid light oil part, it can congeal into a gummy tar, and the axis will not rotate freely.? There is a very strong toxic auto parts cleaner called Berryman B-12 that will totally de-grease the internal bearings...just stuff a rag into the bottom of the shaft opening, and spray in this de-greaser solvent.? Of course, use protective?gear (air mask and rubber gloves, etc) and do this outside.? Once cleaned out if old grease, you must re-lube those internal cylindrical needle bearings.?? If you don't want to de-grease, try WD-40 to free up the needle bearings.? Then add in a Superlube or perhaps a lithium based grease.?? (Superlube makes several formulations. There is a general purpose PTFE gease that says "< 2%" separation and there is a dielectric grease that has 0% separation (also acts as a vacuum grease).? Both are good from -45F to very high temperature.? I'm not sure which is best for lubing the G11 needle bearings...) ______ The Oldham coupler. There is a special mechanical coupler called an Oldham coupler.?? On the strsight-out drive, that critically links the gearbox drive output to the worm gear drive shaft.? On the Tucked Motor version, the coupler attaches the inner transfer gear shaft to the worm drive shaft.?? The metal ends are held on their metal shafts with tiny setscrews, and these can work loose over time and temperature.? When one end gets loose, the drive will either have a time lag, or spin without driving anything.?? Each metal end has an attached polished metal rod. The rods insert into perpendicular grooves on the two sides of a molded plastic center part.? It is a rare but known problem that the 2 tiny allen-head setscrews in the metal Oldham ends can work loose. Then the Oldham coupler might either fully spin, or partly spin.? When that happens, you will have a large time lag (hysteresis) when you reverse axis direction (or the motor spins and the axis does not move!).? Always check both of the Oldham coupler ends grip first when you have time-Iags in your RA or DEC drive.?? The metal rods on each metal end of the Oldham coupler can slide in it's plastic center part groove.? The rods can also pivot. This ingenious coupler design allows a drive shaft (the gearbox) to be offset and at an angle to the worm driven shaft...it will still drive 360 degrees at the same rotation time!? But...just rotating at perfect 4 minute 360 degree intervals is not good enough for precise Astro imaging!? The rotation has to have the same drive speed throughout the 360 degree rotation.? So beware: you don't want the coupler ends to either pivot, or to slide!? If those mechanical movements occur, the worm will have either a slight glitch? or periodic error !? You will see these on?your Astro image!? And in a frequency ("FFT") evaluation, the error from the Oldham coupler will look like it's at the worm period (looks like a bad worm) or at 2x the worm speed (half the period)...looks like a worm with a secondary harmonic.? It's all possibly from a misaligned Oldham coupler.? People have tried other coupler designs (Ruland) but none work as well as a properly aligned Oldham coupler.?? So it is important to look at the Oldham coupler behavior as you fast-slew the motor.? Note: On the older straight-out motor design, you can easily see and adjust the Oldham coupler.? On the newer tucked motor design, the Oldham coupler is totally hidden under the worm drive, so it's impossible to get to.? You'd have to consult Losmandy on how to adjust or fix that case. Probably you'd have to remove the worm drive entirely to get to the coupler hidden inside. That's like the strsight-out OPW design where the Oldham coupler is inside the drive housing.? If you can observe the coupler in action, you will see if the Oldham coupler parts are totally lined up or not.? It is my view that you must try and adjust out as much (ideally all) of the Oldham coupler movement other than pure rotation.?? How can you do that?? The worm is fixed because it is forced fairly tight against the ring gear that is driving the axis.? So the only way (on a straight out drive) you can adjust the Oldham coupler is at the gearbox, where it is mounted.? If that gearbox does not have enough manouver room, you have to enlarge or slot? it's mounting holes to get the optimal position.? (On the tucked motor version you would adjust the inner transfer gear position, though I did not see how to do that on the unit I examined.? It is probably lined up by design at the factory. ) _________ Adjusting the worm gear spacing: The only critical gear spacing was originally thought to be the worm to ring gear spacing.? On newer drives (Spring Loaded Worm), this is automatically done by a spring mechanism.? On the older straight-out drives, you had to adjust this spacing by hand.? The adjustment provided was to loosen the two bottom worm block bolt fasteners, then nudge the worm into the ring gear, then tighten down the worm blocks again.?? _____ Improving worm and bearing performance... Even with the worm gear tight to the ring gear, sometimes there still remained a wiggle in the drive....? many people worked to trace this down.? Finally, it was recognized that the wiggle was coming from a problem that can occur: worm side to side movement.? That is, the worm is only confined by the two blocks on either side, holding the worm bearings (R4ZZ type).? If the blocks are not pressed together at assembly, or loosen up over time and temperature, the worm can move laterally in the gap.? That gap shows up as a time lag in reversing direction, thus can affect autoguiding.?? Moreover, the bearings performance is improved when the bearing is under axial compression.? There is no provision for consistent compression in the stock design.? Earlier mounts like the Meade LXD-55 used a heavy brass bolt to drive the worm axis...but that had no bearing.? So I recommend on older straight out drives to install a R4 size Belleville spring washer.? I have a PDF describing how to do that, but it is not a stock feature.?? I think that ends my list of maintenance and improvements and tools and issues to look for.? ?I'll attach some photos and notes of the newer Tucked Motor and Spring Loaded Worm systems below.?? Have fun with your new mount... ! Michael Photos: Older CG11 worm showing how it drives the large ring gear.? The Oldham coupler is visible at the far end of the worm, with the gearbox.? The AZ hold down bolts go totally slack when you loosen the T handle to do polar (drift) alignment. I find better performance by adding Belleville spring washers under the T handle.? I make the bolts longer and with color caps to be easier to find in near darkness.?? The clutch pad goes at the far end if the 1.25 inch drive shaft.? This photo shows a replacement clutch pad in place. The original pads are milk white.?? This is the Spring Loaded Worm spring mechanism.? The big radial spring pushes the worm down into the ring gear. For this to work properly, the worm must be able to pivot on the left side mounting bolt (not shown in this picture), and the right side hold down bolt must allow the pivoting.? If the bolt pressing the radial spring down is driving too tight, the worm can get stuck (too much friction), so the spring bolt must be loosened up.? The smaller bolt on the left of the spring, when driven in, lifts the worm away from the ring gear.?? This photo shows the two transfer gears of the Tucked Motor drive.? These should have no gap. You adjust the space between these gears by adjusting the gearbox position.? The gearbox is attached to the back of the bottom transfer gear, in this photo.?? On Wed, Jan 1, 2020, 12:29 AM Deric Caselli <JethroStCyr@...> wrote: What spare parts do I need to stock up on to keep the G11 going?? |
Re: Tracking error?
I filed those tabs off to remove the gearbox binding as well. Several different gear boxes exhibited the same binding. I am not sure how you and I are the only people in the world to have noticed this, but we might be.
If you add a belleville washer to you RA bearing, (search this forum and documents for details...), that 3.15x hump in your PEMPro graph should move to 3.0x and then you can smooth it out using PEC from PEMPro to the mount. |
Re: Almost a new owner....
Thank You Paul. I'm not a Raspberry pie user, but appreciate your reply. Thanks!
Thank You for the short list, Chip. Looks like the only thing for me to add is the Gemini ASCOM driver (maybe. It may already be onboard) All the rest I have and have been using. Except the ASCOM controller. I would imagine the ASCOM handset (virtual) will just need getting use to for me. But shouldn't be any problem. This shift to a Losmandy Mount may be much smoother than I imagined. Oh, and my main imaging camera is an Atik Infinity OSC and yep, ASCOM. As is my Orion guide scope and camera for guiding. Edit in: I realized my ASCOM was outdated, so updated it on both computers. Downloaded Gemini ASCOM Driver. Stellarium is currant version. Downloaded Stellarium Scope. And checked PHD2 is the latest. Thank You for the help! Now then... where is my new mount? |
Thread pitch..
¿ªÔÆÌåÓýCan someone tell me the thread pitch of the Losmandy Guidescope adjustment screws?? ? Thanks.. |
Re: static electricity shock
My guess is you are using a switchmode power converter for mount and or camera power??? The power ground outputs of such are never ground but floating wrt to the positive output thru a "Y"class capacitor.? You see similar thing connecting USB leads etc to computer USB ports or interconnecting a computer to a powered USB device.? Sometimes see a little spark as the two PSUs attain equal level.?? The same is happening with your setup.? The main reason is the power supply used the ground is floating and not hard ground.?
https://electronics.stackexchange.com/questions/364659/sparks-when-plugging-in-usb When you touch the metal grd part you act as a big resistor/capacitor to some other gnd level thus you feel a slight shock ....sometimes.? What i do is run a nice clean linear power supply (that connects output gnd (or -ve) to ground) for camera and mount power and keep this separate from other systems like dew control. ? So no other possibility of a ground loop or? differing potentials.? -- Brendan |
Re: Almost a new owner....
>>> The Gemini will need to be started using the touchpad hand controller and once the Gemini is running you can go inside and get comfy. you don't even need to do that! at least, I don't.? when you first connect via it start the mount in whatever mode you set, or ask you to set a mode (warm, cold, etc.) On Tue, Dec 31, 2019 at 5:40 PM Chip Louie <chiplouie@...> wrote: Hi Sonny, --
Brian? Brian Valente portfolio |
Re: Almost a new owner....
Hi Sonny,
Hey welcome, almost! Anyway if you are already happy using the tools you already have there is no reason to change really. The Gemini will need to be started using the touchpad hand controller and once the Gemini is running you can go inside and get comfy. To do this most people are using ASCOM to allow running all of the good software under Windows on a PC such as you have.So here is a short list of links to the basic programs you need to download and install to get your Gemini 2 talking to the computer, find objects in the planetarium Stellarium, autoguide for your existing other apps used to capture and store the data. Post capture processing is up to you, whatever you are using will still work fine. ? Whatever camera control and capture program currently used as long as it is ASCOM compatible. This will get you started.? There is also a fantastic resource for Losmandy users, go and read it over and over: .? ? Enjoy and ask questions! -- Chip Louie - Chief Daydreamer Imagination Hardware |
Re: Almost a new owner....
Hi Sonny almost welcome :) i'm local to losmandy too - just up the road in sherman oaks it kind of depends on the purpose you want to use the mount. it sounds?like you are doing visual? the Losmandy Gemini is one of the most robust and well regarded ascom drivers available, so many programs work well with it. I personally don't use a planetarium program much (i do mostly image sequencing) but i have used both stellarium and sky safari with Losmandy. I'm not 100% sure on how good is the support from stellarium in general. as I recall there were several add-ons that were required, but in the end it ended up working.? I also agree wifi is the better approach, particularly if you are doing visual. the losmandy gemini has an ethernet port and you can get all sort of wifi adapter for it (and usb port as well, if you do usb-> wifi).? hth Brian On Tue, Dec 31, 2019 at 11:42 AM <sonnyedmonds@...> wrote: Hi, brand new here and of course a few questions. --
Brian? Brian Valente portfolio |
Re: Almost a new owner....
¿ªÔÆÌåÓýSonny,I use INDI running on a Raspberry Pi. This is a powerful combination at low cost and uses minimal power all running off low voltage. I control the Raspberry Pi wirelessly from a Mac, but a PC, or iPad/Tablet would work fine, so there are no cables running to the set up. Paul
|
Re: Wireless
I had a lot of head scratchin about remote operation of my mount.
In the end, Bluetooth just does not like going through the outside walls of my home. Where WiFi has no trouble with the right equipment. I run my mount from inside my home. But it was difficult until the fates killed my aging laptop, then my router bellied up, after I got a new portable computer. But I live in California, and in a Stucco sided house. Stucco is like living in a cement box, with a Faraday cage embedded in it. So signals like blue tooth is like a bug on a windshield. Since I run at home almost entirely, power has never been a problem. And the few times I go wandering, I still have power someway. Like my little inverter to run my portable laptop, and my big battery for the mount. But yeah, I'll take WiFi over Blue Tooth any day. Except when BBQing, then I'll take a beer, please. |
Re: Broken Gearbox...frustration, tears, and a little help from Losmandy!
Man! That sure looks like some catastrophic failure going on.
How's the RA drive doing? I'm really encouraged when I hear how Scott and his folks come through for their customers. I hope the replacement settles your other guiding concerns as well. On the bright side, consider if that plastic "Achillie's Heal" was made out of iron parts, it might well have cause a lot worse damage elsewhere. ;^) Happy New Year! |
Re: static electricity shock
¿ªÔÆÌåÓýIf you want to eliminate static (electro static discharge or ESD) damage to installed equipment, after grounding the mount (make sure the contact area is not painted or anodized), you can also install rubber grounding mats around it. Then when you approach the mount step on the mat and touch an exposed (not painted or anodize) surface. Should be foolproof. Possibly not necessary but then I live under the Great Midwest Nebula and have no shortage of water vapor in the air, so who am I to say? I¡¯ll never forget walking into a high bay in one of the Palmdale aircraft assembly sites and being stunned to see fans pushing water spray into the air of the building. And the vapor disappeared a few feet away from the fans. ? But it isn¡¯t the current that zaps circuits ¨C it is the combination of small currents passing through high resistance. Then thanks to Herr Ohm, the voltage is large, like hundreds to thousands of volts. Bang! ? By the way, ESD is usually a handling problem when working with parts prior to them being soldered into circuits, not when they are installed in a system. That¡¯s why many electrical benches have groudnign straps for the wrist of the worker and anti-static mats on the bench itself. It doesn¡¯t have to cause an immediate failure: partial damage can occur on the workbench and then the circuit will fail days, months, or years later. ? A bit of searching with Google will bring further enlightenment. ? Mark C. |
Re: Tracking error?
Oh my goodness, Glen.
Too much time on your hands is right. One thing I've learned in life is to wait, and do tiny steps. I'd bet you could find a happy place somewhere between too loose, and too tight, if you tried. And if you haven't heard from Michael yet, he sells higher friction disks for your mount. But i recon you done wore all the shiny off your new bride before the clouds have parted. You seemed to have put the U in used mount. Scary what you are doing. I finally stopped worrying about what PHD2 was doing, and started concentrating on what my imaging was doing. I can manipulate my PHD2 graph by changing numbers and show flat lines, or honest lines. But the real Proof is in the images from the entire mount. PHD2 can only be as good as what the guide scope can see. And there is way too much variables from night to night to worry about it's graph. I normally set my tripod up as level as I humanly can with a digital level (tenths of a degree accuracy), and spend nights getting my polar alignment the best as I can. And not with some polar scope, but through my camera and telescope. Where the real Meat and Potatoes are. I've gotten great nights, and not so great nights, of imaging when PHD2 had all sorts of willy-waggles with it's nonsensical graph, and scattered Target star results. When I get the bling-bling-bling alarm, and red blink, it's usually the clouds in it's eye. And guiding is a single star event. I can not see using a large telescope for the simple task of guiding. Anyway, stop futzing around and filing on your new bride. She's already looking rode hard and put up wet. |
Re: Mount power supply...
I use the very same sort of meter in my Battery Box I use for my (now gone) AVX.
I like being able to glance down and see the volts and the amperage as my mount goes through various motions, or is just tracking and imaging. It is sensitive enough to show the guiding adjusting the mount with PHD2. Ohhhwah, come on February!? |
Re: static electricity shock
You need to use a personal ground lead for this.
.? Static can amount to thousands of volts, that is why it is so annoying. Most any form of metal in your hand will take away the "Oh DAMN!" of the discharge. Like stepping out of your car, then touch the metal with a key you have your skin? (finger) in contact with. But a personal ground lead between the mount and you puts you at the same potential (charge). Static is a very real danger to electronics. |
Re: Mount power supply
Hi,
I've been using an AGM Group 24 Sealed Lead Acid Battery for a number of years now. I've simply used the fast blow 5 amp fuses that came in the "cigarette" plugs supplied. Like Greg stated, Fuses are for the wiring, not the device. Electronics are prone to catastrophic failures as a rule. If one item fails on a Printed Circuit board it usually causes a cascading effect and blows holes in other parts. Suffices to say, if you blow a fuse, you have a very serious electronic problem. Sorry to hear of your AVX. Mine failed for the 3rd time in 4 years. And I'm done with "off-shore" mounts. So a new Losmandy is in the works for me in February. After the first two "No Responce 16 and No Responce 17" failures, I had the battery ready when my AVX came back. I have 42 years of electrical and electronic background. Nothing has a purer DC currant than a battery does. Both of my AVX failures cam with using an AC/DC adapter from Celestron. What killed my AVX for the 3rd and last time was forgetting to disconnect my battery maintainer, and letting 14 volts hit the AVX on start up. Lucky for me, a friend on another forum PM'd me needing the hardware to fix his AVX and I sold the defunct head to him. After some searching, I found Losmandy, and I found my next and probably last mount. But use a Fast Blow type fuse, 5 Amp. Or less if the Manufacturer recommends it. |