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Hey everyone, first post here.
I have used the G11 mount before and had success with it, but this past weekend, it seems like no matter what I tried, I could not get the alignment correct. ?I purchased the GPS attachment thinking that would make things more accurate and simple, but that didn't seem to help. ?After setting up my mount, I aligned it due north with a compass and waited for sunset to align with Polaris using the polar scope. ?The app I have on my phone to match the reticle never seems to be in the same position when looking through the reticle of the polar scope, but I've never had difficulty aligning before. ?So after aligning Polaris between the correct lines in the reticle, I fired up the mount and used quick start. ?I verified the GPS data with another source and verified the time zone UTC -5, or Central Daylight Time, and ensured the time was also correct, and it was. ?However when using the two bright stars to perfect the alignment, (typically I use Vega and Deneb), the GoTo was way off. ?It would slew but point in totally different directions for either star. ?After using the buttons to slew to the correct position, it still would not go back to the correct spot and then trying to slew back to Polaris did not even work. ?I put everything back in the correct position with CWD and all that, all my cameras pointing at Polaris and tried again using Vega and Arcturus, and then Arcturus and Dubhe and never got good results. ?All my images ended up with trailing and I was using short focal lengths with relatively short shutter times of 3-4 minutes. ?I have previously done 8 minute exposures and had no trailing whatsoever at 24mm focal length on a 35mm full frame. ?For this past weekend I had three cameras mounted and balanced, with an 85mm lens, a 24mm lens, and a medium format camera with 23mm lens (18mm full frame equivalent).
I wanted to also do a series of Andromeda with my 600mm lens, but that would have been out of the question since I was getting trails at short focal lengths.
Any recommendations for how to fix this? ?Honestly, even if the GoTo doesn't take me to the exact position, I'm fine with using the buttons to slew to where I want to go, but I at least need it to track properly.
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I had a similar problem with my G811g earlier this summer. I had input the longitude and latitude in decimal form rather than degrees. When I switched to degrees it has worked fine since.
I'd try there first...if not that I'm sure the wizards on here will have the solution.
Jamey
Hey everyone, first post here.
I have used the G11 mount before and had success with it, but this past weekend, it seems like no matter what I tried, I could not get the alignment correct.? I purchased the GPS attachment thinking that would make things more accurate and simple, but that didn't seem to help.? After setting up my mount, I aligned it due north with a compass and waited for sunset to align with Polaris using the polar scope.? The app I have on my phone to match the reticle never seems to be in the same position when looking through the reticle of the polar scope, but I've never had difficulty aligning before.? So after aligning Polaris between the correct lines in the reticle, I fired up the mount and used quick start.? I verified the GPS data with another source and verified the time zone UTC -5, or Central Daylight Time, and ensured the time was also correct, and it was.? However when using the two bright stars to perfect the alignment, (typically I use Vega and Deneb), the GoTo was way off.? It would slew but point in totally different directions for either star.? After using the buttons to slew to the correct position, it still would not go back to the correct spot and then trying to slew back to Polaris did not even work.? I put everything back in the correct position with CWD and all that, all my cameras pointing at Polaris and tried again using Vega and Arcturus, and then Arcturus and Dubhe and never got good results.? All my images ended up with trailing and I was using short focal lengths with relatively short shutter times of 3-4 minutes.? I have previously done 8 minute exposures and had no trailing whatsoever at 24mm focal length on a 35mm full frame.? For this past weekend I had three cameras mounted and balanced, with an 85mm lens, a 24mm lens, and a medium format camera with 23mm lens (18mm full frame equivalent).
I wanted to also do a series of Andromeda with my 600mm lens, but that would have been out of the question since I was getting trails at short focal lengths.
Any recommendations for how to fix this?? Honestly, even if the GoTo doesn't take me to the exact position, I'm fine with using the buttons to slew to where I want to go, but I at least need it to track properly.
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Hi Doug(?)
It sounds like your polar alignment was too far off if tracking is trailing at short focal length in a matter of minutes. The other possible reasons for this: wrong tracking rate selected in Gemini (should be Sidereal), wrong mount type selected resulting in the wrong tracking speed, or something is very loose in your imaging train causing image to shift as the mount tracks.? I'd investigate these first. GPS, time and coordinates are all important for a better initial goto, but not important at all for tracking at Sidereal rate.
Regards,
? ? ?-Paul
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Sorry to read of your headache getting proper performance. It seems that your G11 has a very light payload, as your lenses seem very light compared to the strength of this G11 mount.? So? something is mis-set... let's try a checklist to "round up the usual suspects" to steal a line from Casablanca.
1. COLD BOOT your Gemini.? ?You have not mentioned this, so I'll put it first on the list.? Remember that the Gemini always reads its Model values and offers first to Warm Boot.? The Model parameters are a bunch of corrections to a perfect mount.? The values consist?of error corrections for polar alignment, counterweight bar flex, errors in AZ and ELevation.? Warm Boot sounds like a great idea, if you have not moved anything.? But as soon as you shift anything...the Elevation knob, the AZ rotation, to polar align, the prior model data is worthless?and even worse... the mount will be making the wrong corrections.? So when any pointing goes awry, first suspect the Model data is bogus.? Do a Park at CWD, torn off the Gemini, and reboot it in Cold Boot mode.
2. Is something slipping?? It sounds absurd that such a strong mechanical system could ever slip, but if you've ever tried to drive a car with a worn out clutch, you know the problem.? The clutch system uses thick plastic disks, one each in RA and one in DEC, to hold position.? You can clean these disks rather easily, but it means removing your scope first, then counterweights and bar, then pulling out the DEC axis from the RA axis, then pulling out the?RA axis from the mount head.? Then yank out the clutch disks, cleaning them and the metal mating surfaces in something like isopropyl alcohol. while those 1.25 inch shafts are out, it's sensible to see if you can rotate the needles of the needle bearings with your finger.? If those are sticking, due to "gummed up" old lubricant, it is time to use some nasty degreasing chemical to remove all the old grease. [Nasty means it must be done outdoors with rubber protective gloves and a face mask...something like an automotive degreaser like Berryman B-12 works well...you spray in some of that and catch the residue in a metal bucket...this stuff will dissolve a plastic bucket.? ?Just be very careful.]? ?I'll add that I make a high friction clutch disk for our mounts that holds much better than the stock plastic clutch pads and also retards or prevents oil migration on to those plastic and metal clutch surfaces.? Let me know if you need such things.]
3. Other things can get loose and move or shift.? Be sure to tighten down your RA and EL hold down bolts after polar aligning!? The stock thumbscrews are 3/8-16 thread.? They have only got flat washers under the bolt head.? When you loosen those AZ bolts, the mount head is only held by a central rotation bold under the middle center under the mount head.? That likewise also only has a flat washer...or even No washer at all.? So I put in (you guessed it) 3/8 Belleville spring washers bounded by flat washers in those 3/8-16 bolts locations.? Then when you loosen the AZ or EL, the bottom bold is always being held with some spring force in the bottom center, and the AZ bolts also have some now-adjustable force to hold the AZ in position.??
4. I found one of my tripod legs was slightly?slipping?length over time.? The problem was the heavy weight of my scope, and the huge hand knobs that hold the legs position started to loosen over time and temperature.? Be sure those legs adjusters are really tight.? This was the last thing in the world that I ever suspected...in your case, with such? a light load on the mount, it seems unlikely but I'll leave it on the checklist.??
5. Others already mentioned that the data entry for Latitude and Longitude use a decimal point entry.? But it is NOT a decimal point!? It is instead a European style comma!? So you enter Degrees.Minutes? ?not Degrees.Fraction.? ?(If your minutes are near zero, of course, it will not matter.? I can't imagine what devilish havoc is caused if you enter something?over 59 in the degrees entry...maybe you can't?? Something like longitude "122.97" ?? )? (No... IO won't try that to see!)
6. The polar scope...? ?this is a wonderful invention.? But it is prone to difficulty.? The Losmandy style polar scope is better than others like the one in the Orion Atlas/Synta EQ6... but none of them are perfect.? The problem is that the glass "reticula" is held by 3 tiny metal screws that must always be somewhat loose from the round glass reticule plate inside.? If too tight,the glass will get cracked.? As you rotate the RA or the plasr scope around to get the stars lined up,, the glass plate can shift and mess up the visual point of the NCP (or SCP) point.? So I use a drift align to follow up and check polar alignment?before deep sky imaging.??
There are other polar alignment gadgets these days that are highly praised.? I don't yet have one but it's on my shopping list.? Another local group member came by to pick up a Gemini-1 I just fixed for him, and he told me he has some recommendations for this... as others?on this forum have praised.??
7 As Paul mentioned in his following email, beware of GPS data.? I always hand enter UTC time, not local time.? [The entry coding is:? YYMM.DD?HH:MM:SS? like 2008.18 20:15:59? ] you mentioned that you checked and found your local time was UTC -5 hours.? That's nice to see, but given the crazy way daylight savings time dates get changed these nutty times, always enter only the UTC time (from a website giving the current UTC time of course).? And if your Latitude and Longitude are correct, the local sidereal time (LST) will be correct.??
8. Related to this is the problem with some GPS units (namely older GPS models don't' read the latest GPS codes right and get the wrong UTC time or maybe wrong position data.? There was a whole?discussion of this problem... leading some to say their old GPS unit could not read the latest satellite information being sent.? Anway, the bottom line is:? also suspect GPS provided information and double check that.? ?
9. As Paul mentioned (in the email following), you?may easily have left your Gemini?in some tracking mode like Lunar, or maybe Solar (we have sunspots again, yeah!).? So double check the tracking rate is really Sidereal.??
That's about it... try this checklist first, and let us know if the problem went away!
All the best, Michael
I had a similar problem with my G811g earlier this summer. I had input the longitude and latitude in decimal form rather than degrees. When I switched to degrees it has worked fine since.
I'd try there first...if not that I'm sure the wizards on here will have the solution.
Jamey
Hey everyone, first post here.
I have used the G11 mount before and had success with it, but this past weekend, it seems like no matter what I tried, I could not get the alignment correct.? I purchased the GPS attachment thinking that would make things more accurate and simple, but that didn't seem to help.? After setting up my mount, I aligned it due north with a compass and waited for sunset to align with Polaris using the polar scope.? The app I have on my phone to match the reticle never seems to be in the same position when looking through the reticle of the polar scope, but I've never had difficulty aligning before.? So after aligning Polaris between the correct lines in the reticle, I fired up the mount and used quick start.? I verified the GPS data with another source and verified the time zone UTC -5, or Central Daylight Time, and ensured the time was also correct, and it was.? However when using the two bright stars to perfect the alignment, (typically I use Vega and Deneb), the GoTo was way off.? It would slew but point in totally different directions for either star.? After using the buttons to slew to the correct position, it still would not go back to the correct spot and then trying to slew back to Polaris did not even work.? I put everything back in the correct position with CWD and all that, all my cameras pointing at Polaris and tried again using Vega and Arcturus, and then Arcturus and Dubhe and never got good results.? All my images ended up with trailing and I was using short focal lengths with relatively short shutter times of 3-4 minutes.? I have previously done 8 minute exposures and had no trailing whatsoever at 24mm focal length on a 35mm full frame.? For this past weekend I had three cameras mounted and balanced, with an 85mm lens, a 24mm lens, and a medium format camera with 23mm lens (18mm full frame equivalent).
I wanted to also do a series of Andromeda with my 600mm lens, but that would have been out of the question since I was getting trails at short focal lengths.
Any recommendations for how to fix this?? Honestly, even if the GoTo doesn't take me to the exact position, I'm fine with using the buttons to slew to where I want to go, but I at least need it to track properly.
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In addition to verifying that you are not in lunar or solar, make sure that your dec wire is in fact to dec and RA to RA.? Sounds stoopid but I have confused the wires more than once.
Sometimes the wires are OK but one is not completely plugged in.
I would only use GPS if you can't see Polaris.
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I always like posts like this. I can come along after the usual prospectors and usually pick up a few nuggets.
I've never extended the legs on my tripod. Never had the need. But I think Michael's Point 4 has merit for me. So I will check that my leg clamps are tight.
That nugget was not missed by me, Michael. ;^)
I've almost always checked my tripods level and plumb as I begin my set up for the evening. (Which hasn't been lately due to heat, smoke, and clouds.)
My tripod remains set up on it's leveling pads I made for it, covered but ready to assemble my "chunks" and begin a session.
If I was to be accused of anything, it would probably be of tightening a smidgen too tight. I often notice this when breaking down and I look around for the gorilla who tightened my clamp on my D-bar.
I always handle my mount like it was made of glass. Not because I think I will hurt it, but out of my respect for how well made and beautiful I think it is.
And not banging it around keeps things as set from the previous sessions.
But for those who do extend their tripods legs, making sure they are tight is a very prudent point.
To me, .001" (0.0254 mm) on Mother Earth, can amount to a clear miss in Deep Space Objects. 8^0
--
SonnyE
(I suggest viewed in full screen)
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In addition to verifying that you are not in lunar or solar, make sure that your dec wire is in fact to dec and RA to RA.? Sounds stoopid but I have confused the wires more than once.
Sometimes the wires are OK but one is not completely plugged in.
I would only use GPS if you can't see Polaris.
Greg, What does the GPS have to do with seeing Polaris?? -- Chip Louie - Chief Daydreamer Imagination Hardware
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Hey everyone, first post here.
I have used the G11 mount before and had success with it, but this past weekend, it seems like no matter what I tried, I could not get the alignment correct. ?I purchased the GPS attachment thinking that would make things more accurate and simple, but that didn't seem to help. ?After setting up my mount, I aligned it due north with a compass and waited for sunset to align with Polaris using the polar scope. ?The app I have on my phone to match the reticle never seems to be in the same position when looking through the reticle of the polar scope, but I've never had difficulty aligning before. ?So after aligning Polaris between the correct lines in the reticle, I fired up the mount and used quick start. ?I verified the GPS data with another source and verified the time zone UTC -5, or Central Daylight Time, and ensured the time was also correct, and it was. ?However when using the two bright stars to perfect the alignment, (typically I use Vega and Deneb), the GoTo was way off. ?It would slew but point in totally different directions for either star. ?After using the buttons to slew to the correct position, it still would not go back to the correct spot and then trying to slew back to Polaris did not even work. ?I put everything back in the correct position with CWD and all that, all my cameras pointing at Polaris and tried again using Vega and Arcturus, and then Arcturus and Dubhe and never got good results. ?All my images ended up with trailing and I was using short focal lengths with relatively short shutter times of 3-4 minutes. ?I have previously done 8 minute exposures and had no trailing whatsoever at 24mm focal length on a 35mm full frame. ?For this past weekend I had three cameras mounted and balanced, with an 85mm lens, a 24mm lens, and a medium format camera with 23mm lens (18mm full frame equivalent).
I wanted to also do a series of Andromeda with my 600mm lens, but that would have been out of the question since I was getting trails at short focal lengths.
Any recommendations for how to fix this? ?Honestly, even if the GoTo doesn't take me to the exact position, I'm fine with using the buttons to slew to where I want to go, but I at least need it to track properly.?
Hi Doug,
Sorry to hear of your problems with the G11. First a GPS will only help the Gemini get its initial positional GOTO closer. Once polar aligned and even a single star model is built the Gemini knows where it is in that part of the sky.
A few questions, which Gemini are you using? Did you install a battery you tested @ 3.0V or higher? Do you know that Gemini GPS coordinates are entered using DMS format? If your GPS was a recent purchase do you know if it has the firmware fix for GPS rollover? If you are using well know navigational stars for Gemini alignment and your GOTOs are off and you cannot slew and return to a once centered location you have a few potential issues.
The troubleshooting checklist I use is: test battery, wipe battery clip contacts and install battery, do a full factory reset, verify GPS data you used is correct and entered using DSM format, enter UTC and only use UTC - no need for local offset, verify time format is entered using correct Gemini format is different, verify polar alignment. If you do this checklist 99.9% of all issues are resolved.?
--?
Chip Louie - Chief Daydreamer Imagination Hardware
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When my G11 has had either bad goto or bad tracking, here are the problems I have found:
1. Bad polar alignment.? This is by far the most likely culprit, IMO.? Unless you¡¯ve done a good drift alignment, or correctly used an electronic aid like PoleMaster, that would be top of the list of things to check.? Aside from the physical hassles of dealing with the polar scope, a polar scope gives ?a rough alignment even if you did it perfectly, and if you made a mistake, it¡¯s not polar alignment at all, just a recipe for frustration . ? 2. Poorly balanced axes.? This can cause slipping in the clutches, which will throw your goto off, and kill your tracking. ? I am sure there are other possible causes, but these are the simple ones. ? Mark ?
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From: [email protected] < [email protected]> On Behalf Of dougwheeler90@... Sent: Monday, August 17, 2020 8:06 PM To: [email protected]Subject: [Losmandy_users_io] G11 Mount Not Tracking Correctly ? Hey everyone, first post here.
I have used the G11 mount before and had success with it, but this past weekend, it seems like no matter what I tried, I could not get the alignment correct. ?I purchased the GPS attachment thinking that would make things more accurate and simple, but that didn't seem to help. ?After setting up my mount, I aligned it due north with a compass and waited for sunset to align with Polaris using the polar scope. ?The app I have on my phone to match the reticle never seems to be in the same position when looking through the reticle of the polar scope, but I've never had difficulty aligning before. ?So after aligning Polaris between the correct lines in the reticle, I fired up the mount and used quick start. ?I verified the GPS data with another source and verified the time zone UTC -5, or Central Daylight Time, and ensured the time was also correct, and it was. ?However when using the two bright stars to perfect the alignment, (typically I use Vega and Deneb), the GoTo was way off. ?It would slew but point in totally different directions for either star. ?After using the buttons to slew to the correct position, it still would not go back to the correct spot and then trying to slew back to Polaris did not even work. ?I put everything back in the correct position with CWD and all that, all my cameras pointing at Polaris and tried again using Vega and Arcturus, and then Arcturus and Dubhe and never got good results. ?All my images ended up with trailing and I was using short focal lengths with relatively short shutter times of 3-4 minutes. ?I have previously done 8 minute exposures and had no trailing whatsoever at 24mm focal length on a 35mm full frame. ?For this past weekend I had three cameras mounted and balanced, with an 85mm lens, a 24mm lens, and a medium format camera with 23mm lens (18mm full frame equivalent).
I wanted to also do a series of Andromeda with my 600mm lens, but that would have been out of the question since I was getting trails at short focal lengths.
Any recommendations for how to fix this? ?Honestly, even if the GoTo doesn't take me to the exact position, I'm fine with using the buttons to slew to where I want to go, but I at least need it to track properly.
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Hi Doug!
Did you ever resolve your original issue?
If yes, what things worked?
If not, please contact me!
Best of luck, Michael
On Sat, Aug 22, 2020, 11:27 AM Mark de Regt < deregt@...> wrote: When my G11 has had either bad goto or bad tracking, here are the problems I have found:
1. Bad polar alignment.? This is by far the most likely culprit, IMO.? Unless you¡¯ve done a good drift alignment, or correctly used an electronic aid like PoleMaster, that would be top of the list of things to check.? Aside from the physical hassles of dealing with the polar scope, a polar scope gives ?a rough alignment even if you did it perfectly, and if you made a mistake, it¡¯s not polar alignment at all, just a recipe for frustration . ? 2. Poorly balanced axes.? This can cause slipping in the clutches, which will throw your goto off, and kill your tracking. ? I am sure there are other possible causes, but these are the simple ones. ? Mark ? ? Hey everyone, first post here.
I have used the G11 mount before and had success with it, but this past weekend, it seems like no matter what I tried, I could not get the alignment correct.? I purchased the GPS attachment thinking that would make things more accurate and simple, but that didn't seem to help.? After setting up my mount, I aligned it due north with a compass and waited for sunset to align with Polaris using the polar scope.? The app I have on my phone to match the reticle never seems to be in the same position when looking through the reticle of the polar scope, but I've never had difficulty aligning before.? So after aligning Polaris between the correct lines in the reticle, I fired up the mount and used quick start.? I verified the GPS data with another source and verified the time zone UTC -5, or Central Daylight Time, and ensured the time was also correct, and it was.? However when using the two bright stars to perfect the alignment, (typically I use Vega and Deneb), the GoTo was way off.? It would slew but point in totally different directions for either star.? After using the buttons to slew to the correct position, it still would not go back to the correct spot and then trying to slew back to Polaris did not even work.? I put everything back in the correct position with CWD and all that, all my cameras pointing at Polaris and tried again using Vega and Arcturus, and then Arcturus and Dubhe and never got good results.? All my images ended up with trailing and I was using short focal lengths with relatively short shutter times of 3-4 minutes.? I have previously done 8 minute exposures and had no trailing whatsoever at 24mm focal length on a 35mm full frame.? For this past weekend I had three cameras mounted and balanced, with an 85mm lens, a 24mm lens, and a medium format camera with 23mm lens (18mm full frame equivalent).
I wanted to also do a series of Andromeda with my 600mm lens, but that would have been out of the question since I was getting trails at short focal lengths.
Any recommendations for how to fix this?? Honestly, even if the GoTo doesn't take me to the exact position, I'm fine with using the buttons to slew to where I want to go, but I at least need it to track properly.
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I was using the GPS, so it pulled data from there automatically. ?I did verify it was correct.
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Thanks, Michael!
The gears definitely were not slipping, I did check all of that. ?I always cold start, so I don't think that was the issue. ?I thought the Cold Start always deleted previous data.
As for the others, everything was tight, so the tracking was not off because of that.
And the GPS is brand new. ?I bought it from OPTCorp website the week before. ?I verified the coordinates and UTC time.
The tracking mode was sidereal, I haven't changed that at all.
I haven't had a chance to set the mount up again to try, but I'm hoping to one night this week. ?
Doug
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Yep, all the wires were connected properly. ?I always check and double check before powering on.
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I don't know if the GPS has the firmware fix for GPS rollover. ?But I did verify everything. ?Using the buttons I could manually slew to where I wanted, but the tracking was off. ?The polar alignment was good, but then it would overshoot everything in the GOTO, including trying to use stars to verify alignment.
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I'm hoping to get back out one night this week and try in my backyard. ?I'll post back with my results.
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Hi Doug
"?I verified the coordinates and UTC time."
just confirming, the time you should be entering into Gemini should be local time, and the timezone should offset that to UTC. you should not enter UTC time
"Using the buttons I could manually slew to where I wanted, but the tracking was off.? "
if tracking is off (I assume you can visually see it not tracking correctly), Chip mentioned some of these before, but recapping the possible causes:
- incorrect mount type selected
- incorrect gearing for the mount (check the gearing page for G11, the first two should be RA Worm Gear 360 and DEC Worm Gear 360)
- not on sidereal tracking (lunar, solar, custom, etc.)
- motor cables plugged in to the wrong port (RA/DEC cables reversed)
Some of the above could also contribute to or cause inaccurate gotos
Brian
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Hi Doug
one more thing regarding the polar scope, and your comment "The app I have on my phone to match the reticle never seems to be in the same position when looking through the reticle of the polar scope...."
just to confirm, you rotate the polar scope so the position of polaris would line up with the app on your phone
Brian
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Going back to bone simple...
Have you tried a Factory Reset?
(I'm assuming your G11 has a Gemini II. Because I am ignorant if this is available with a Gemini I.)
Just thought I would through that in there. (Not that I'm ignorant. That maybe a Factory Reset could help flush any turds out of the controller.)
One other thing I've made a habit of is to use the Quick Start. It gives me a review of my settings, then drops me at a cold start.
But with the assurance my settings are hunky-dory, before I start. ;^)
--
SonnyE
(I suggest viewed in full screen)
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Sonny,
I already posted to do a factory reset a few weeks ago.?
--
Chip Louie Chief Daydreamer Imagination Hardware?
? ?Astropheric Weather Forecast - South Pasadena, CA?
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Paul Kanevsky
Michael Herman
Chip Louie