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I can see this has been discussed a lot here, and am going to take some time to read some of the threads on it later, but just wanted to add my voice, and could not find any discussion later than 2017 (doing a search just for "pointing.")? I'm sure there are others who've had problems with pointing since then.
I have a GM811G.? As far as I can tell I've done everything according to the book (and videos and some discussions I've read on Cloudy Nights and elsewhere).? Checked battery.? Did factory reset and re-entered parameters just to be sure that wasn't a factor.? I use UTC, not local time.? Made sure balance was good.? Checked and double-checked leveling with CWD.? Got great polar alignment with PoleMaster.? Did the modeling routine according to the directions.
And pointing was still off - sometimes way off.? Went to a catalog object and it was not even in my camera viewfinder screen.? To give an example, after modeling, I slewed back to Arcturus to focus, then slewed to Spica, and it was not nearly centered.? Did an alignment on Spica.? Slewed back to Arcturus, and IT was now well off center.? Did the alignment routine on Arcturus, then slewed to Mizar.? WAY off!? Aligned on Mizar (yes, according to the prescribed routine of Menu> Align > Bright Star > Center > Align > Alignment.? Went back to Arcturus, and it was still off.
The only way I'm currently able to center objects I want to image is by slewing to a brlght star somewhere near the object, performing the alignment routine, then slewing to the object.? Even then, I sometimes need to make slight corrections to center the object a little.? When I bought this mount (hardly used, practically like new), I was had high expectations to be done dealing with this sort of thing (and we won't get into tracking, which is good, but not as good as I'd hoped, even with good seeing).? I do really like the mount, and just hope I'll be able to do something to get it to point (and maybe track) better.
So, I have absolutely no idea where to go from here.? Just hoping something will "click" that either I'm doing wrong, or the Gemini 2 is doing wrong.
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Hi AstroItalian!
I hear Ya. It can get to be frustrating. And downright piss you off.
I struggled like a worm in a birds beak for my first year or more. Probably because I just dove in with my best guesses based on refining wish lists aimed at my goal of Astroimaging.
In those struggles, I made progress, and eventually got things working. One thing for sure is that the most minute change can affect so much in this stuff.
Think about it, I found that just the ground vibrations of me walking near my mount telegraphed into the images. I finally had to take to not moving at all, and even breathing slow and methodically so I don't cause star bloating due to vibrations.
Many have chastised me for my insistence on tripod leveling. Long have I worked around various massive machines and equipment. And seen the great pains taken to make sure they were level, and then actually grouted to the foundations with a loose grout slurry. All to insure they were as stable as possible. And that the axis of them were as straight horizontally or vertically as was possible. To remove as much human error as possible.
So it is when setting up my mount. If I take the extra time to try and get things on as true a plane to the Earth's Axis, the better the chances of my telescope running true when it turns on it's axis'. A little extra care will hopefully get better results.
So I use an electronic digital level, and a plate of cold rolled 5/16" thick steel to get my tripod to 0.0¡ã on 3 axis (the tripod legs). That way I'm assured I'm beginning from as good a platform as I humanly can, each session.
Night... after... night...? Even when my tripod is left set up, I still check it. With my GM811G, on my homemade level adjusters, it is usually still at 0.0¡ã of level.
So a good base for the rest to land upon. Because, to me, accuracy counts.
Because my primary interest is Astroimaging, I use my cameras to center my Modeling (or alignment) Stars. My final aim point is always with imposed crosshairs in my main imaging camera. The idea is, again, accuracy and human error reduction.
Interestingly enough, last night when building my Model from the start up, it chose Arcturus as the first Star. When it slew to the next Star, it was off by a mile. Way off! I brought it back to the Brightest Star in my immediate FOV, and selected Align on it. But it got worse after that. Not one to waste my time, I told the mount to Go-To Park, Counterweight Down. And it missed that substantially.
So I shut down the Gemini 2, and physically brought everything back to Polaris, checked my camera alignment on Polaris as a starting point, then began again. The only thing I could imagine was the clutches slipping to mess things up with the first attempt. So those were snugged up before beginning again. The second attempt was normal and without gremlins crawling in and out.
After my plate solver did a good solve, it suggested I run it again. After that it just could not solve again.
So I tried SharpCap for Polar Aligning, for the first time. Everybody seems to like it, even when it is the only part of SharpCap they use. So I figured "Follow the Herd". LOL! Well, it got me pretty far, but that's a Pay-To-Play part, you gotta go Pro.
So I went Pro and put my $15 USD in their coffers.
But after that, all I did was to fritter away with settings and starting overs, and closing it several times, and rebooting my Baby Dell. I came back inside and went webbing around for tutorials.....
I woke up around 1 AM with a kink in my neck, and went out to start a new sequence, even though still wondering if I had done any good with my fooling around. The Sequence was for M66 from a very good friend. But my plate solving seemed to get stuck.
I could see the Leo Trio in the Image, but ASTAP couldn't solve it. Finally, around 2 AM I called it quits, shut down and tore down and dragged it all in. Tonight will be a new night to play again.
So, sometimes there just isn't any rhyme of reason to this stuff. No matter what it kicks your butt, then sends you to bed. Then, magically, the next night everything works like it should.
But eventually, there are more great nights, than there are the bad ones. Because that's where the Perseverance part comes in, Ya don't give up.
--
SonnyE
(I suggest viewed in full screen)
|
Sonny
>>>Interestingly enough, last night when building my Model from the start up, it chose Arcturus as the first Star. When it slew to the next Star, it was off by a mile
was the next star on the opposite side of pier? because that's essentially starting from scratch as well i.e., it's the first star of the second model
Hi AstroItalian!
I hear Ya. It can get to be frustrating. And downright piss you off.
I struggled like a worm in a birds beak for my first year or more. Probably because I just dove in with my best guesses based on refining wish lists aimed at my goal of Astroimaging.
In those struggles, I made progress, and eventually got things working. One thing for sure is that the most minute change can affect so much in this stuff.
Think about it, I found that just the ground vibrations of me walking near my mount telegraphed into the images. I finally had to take to not moving at all, and even breathing slow and methodically so I don't cause star bloating due to vibrations.
Many have chastised me for my insistence on tripod leveling. Long have I worked around various massive machines and equipment. And seen the great pains taken to make sure they were level, and then actually grouted to the foundations with a loose grout slurry. All to insure they were as stable as possible. And that the axis of them were as straight horizontally or vertically as was possible. To remove as much human error as possible.
So it is when setting up my mount. If I take the extra time to try and get things on as true a plane to the Earth's Axis, the better the chances of my telescope running true when it turns on it's axis'. A little extra care will hopefully get better results.
So I use an electronic digital level, and a plate of cold rolled 5/16" thick steel to get my tripod to 0.0¡ã on 3 axis (the tripod legs). That way I'm assured I'm beginning from as good a platform as I humanly can, each session.
Night... after... night...? Even when my tripod is left set up, I still check it. With my GM811G, on my homemade level adjusters, it is usually still at 0.0¡ã of level.
So a good base for the rest to land upon. Because, to me, accuracy counts.
Because my primary interest is Astroimaging, I use my cameras to center my Modeling (or alignment) Stars. My final aim point is always with imposed crosshairs in my main imaging camera. The idea is, again, accuracy and human error reduction.
Interestingly enough, last night when building my Model from the start up, it chose Arcturus as the first Star. When it slew to the next Star, it was off by a mile. Way off! I brought it back to the Brightest Star in my immediate FOV, and selected Align on it. But it got worse after that. Not one to waste my time, I told the mount to Go-To Park, Counterweight Down. And it missed that substantially.
So I shut down the Gemini 2, and physically brought everything back to Polaris, checked my camera alignment on Polaris as a starting point, then began again. The only thing I could imagine was the clutches slipping to mess things up with the first attempt. So those were snugged up before beginning again. The second attempt was normal and without gremlins crawling in and out.
After my plate solver did a good solve, it suggested I run it again. After that it just could not solve again.
So I tried SharpCap for Polar Aligning, for the first time. Everybody seems to like it, even when it is the only part of SharpCap they use. So I figured "Follow the Herd". LOL! Well, it got me pretty far, but that's a Pay-To-Play part, you gotta go Pro.
So I went Pro and put my $15 USD in their coffers.
But after that, all I did was to fritter away with settings and starting overs, and closing it several times, and rebooting my Baby Dell. I came back inside and went webbing around for tutorials.....
I woke up around 1 AM with a kink in my neck, and went out to start a new sequence, even though still wondering if I had done any good with my fooling around. The Sequence was for M66 from a very good friend. But my plate solving seemed to get stuck.
I could see the Leo Trio in the Image, but ASTAP couldn't solve it. Finally, around 2 AM I called it quits, shut down and tore down and dragged it all in. Tonight will be a new night to play again.
So, sometimes there just isn't any rhyme of reason to this stuff. No matter what it kicks your butt, then sends you to bed. Then, magically, the next night everything works like it should.
But eventually, there are more great nights, than there are the bad ones. Because that's where the Perseverance part comes in, Ya don't give up.
--
SonnyE
(I suggest viewed in full screen)
-- Brian?
Brian Valente portfolio
|
Sonny, loved your post!!!? Your final statement is so true - "no rhyme nor reason."? My wife likes to join me outside and has seen my struggles first hand, and now understands that statement fully.? One night I'll be happy as a lark, with everything going smooth as butter.? The next night, set up exactly the same way, do exactly the same routine, and NOTHING works.? Not to mention that same night you'll get some unusual bright light, or maybe the mosquitoes will be more hungry than usual, or who knows what (clouds?? I won't even go there).
The part about breathing slow cracked me up too.? The place we lived before we moved to where we are now had a concrete slab driveway.? I would set up my scope, start imaging and quickly and gingerly move off the concrete slab the scope was on so as to minimize any movement or vibrations that would show up in my images.? And yes, I do use vibration dampers.
Someone else (privately) suggested that the clutches could be an issue.? It's hard to know what's too tight, and what's not tight enough.? I'll pay more attention to that tonight.? As for SharpCap, I thought about that, but I now have Astrophotography Tool, so if I want to do plate solving for PA, I could do that, but I think my PA using PoleMaster is good enough, really.
Finally, the Leo Trio was my first target last night, and just like last time, I got a nice satellite trail right thru one of the images.? You really gotta love this hobby to put up with all the crapola we deal with!? Perseverance for sure!
Unfortunately I have no suggestions to maybe help you out.? I guess I'm where you were as that worm in the bird's mouth right now.
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My own gotcha the other night was:
My USB and dew heater cables somehow snagged and held back the mount tracking ... erratically.??
So I took advice I'd ignored for years, and tied them all to the scope and along the axis, so the axes can rotate and they can't snag.??
I'll attempt to prove it tonight, on a? semiclear night.??
Have fun, all,
Michael
Sonny, loved your post!!!? Your final statement is so true - "no rhyme nor reason."? My wife likes to join me outside and has seen my struggles first hand, and now understands that statement fully.? One night I'll be happy as a lark, with everything going smooth as butter.? The next night, set up exactly the same way, do exactly the same routine, and NOTHING works.? Not to mention that same night you'll get some unusual bright light, or maybe the mosquitoes will be more hungry than usual, or who knows what (clouds?? I won't even go there).
The part about breathing slow cracked me up too.? The place we lived before we moved to where we are now had a concrete slab driveway.? I would set up my scope, start imaging and quickly and gingerly move off the concrete slab the scope was on so as to minimize any movement or vibrations that would show up in my images.? And yes, I do use vibration dampers.
Someone else (privately) suggested that the clutches could be an issue.? It's hard to know what's too tight, and what's not tight enough.? I'll pay more attention to that tonight.? As for SharpCap, I thought about that, but I now have Astrophotography Tool, so if I want to do plate solving for PA, I could do that, but I think my PA using PoleMaster is good enough, really.
Finally, the Leo Trio was my first target last night, and just like last time, I got a nice satellite trail right thru one of the images.? You really gotta love this hobby to put up with all the crapola we deal with!? Perseverance for sure!
Unfortunately I have no suggestions to maybe help you out.? I guess I'm where you were as that worm in the bird's mouth right now.
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On Fri, Apr 24, 2020 at 12:21 PM, Brian Valente wrote:
>>>Interestingly enough, last night when building my Model from the start up, it chose Arcturus as the first Star. When it slew to the next Star, it was off by a mile
?
was the next star on the opposite side of pier? because that's essentially starting from scratch as well i.e., it's the first star of the second model
I don't rightly recall Brian. I think they were in the same area. So much so, the mount did not move much. Which made me think it would be a bad to marginal model anyway. I looked up at gathering mists, and decided to pack it in. (Damn Mists were probably a new batch of Corona virus... 8^0 ) But my ASTAP seems to gone to heck on me. Most likely I changed a setting and messed it up. So I might go down to ground zero, remove ASTAP, then reinstall it. I haven't had a solve in several nights now. Not even on M66, which looks fine in the preview. I can see it is M66, but Plate Solve? No Way! I always suspect that guy in the mirror first. I know he uses my razor when I'm not looking. ? -- SonnyE (I suggest viewed in full screen)
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well, we know you can plate solve, your camera, settings, and mount all checked out
so something must have changed :)
On Fri, Apr 24, 2020 at 12:21 PM, Brian Valente wrote:
>>>Interestingly enough, last night when building my Model from the start up, it chose Arcturus as the first Star. When it slew to the next Star, it was off by a mile
?
was the next star on the opposite side of pier? because that's essentially starting from scratch as well i.e., it's the first star of the second model
I don't rightly recall Brian. I think they were in the same area. So much so, the mount did not move much. Which made me think it would be a bad to marginal model anyway.
I looked up at gathering mists, and decided to pack it in. (Damn Mists were probably a new batch of Corona virus... 8^0 )
But my ASTAP seems to gone to heck on me. Most likely I changed a setting and messed it up. So I might go down to ground zero, remove ASTAP, then reinstall it.
I haven't had a solve in several nights now. Not even on M66, which looks fine in the preview. I can see it is M66, but Plate Solve? No Way!
I always suspect that guy in the mirror first. I know he uses my razor when I'm not looking.
?
--
SonnyE
(I suggest viewed in full screen)
-- Brian?
Brian Valente portfolio
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On Fri, Apr 24, 2020 at 04:01 PM, Michael Herman wrote:
My own gotcha the other night was:
?
My USB and dew heater cables somehow snagged and held back the mount tracking ... erratically.??
Me Too, Michael! But mine was some errant slew. I was operating remote from my inside Box-O-Rocks. Suddenly it stopped slewing. I went out and found my harness wrapped around the Dec axis. Oy! Come to think about it, maybe things have never really recovered from that? I haven't done it, but maybe I need to format the SD card, then reset it to factory original. Pretty harsh, but I haven'y gone that deep before, yet. With my old mount, my harness exited down the CW shaft. That way it was controlled by the motions the mount took. Radical approach, but it worked. And a "drip Loop" with a Ball Bungee mount at the accessory tray. I'm considering using some ball bungee attachments to allow more flexibility.? Being at the mount is one thing, I can watch it. But being remote like I do is quite another. Never a dull moment in this sport. LOL! Okay, back to that guy in the mirror. I think he causes me no end to grief. LOL! ? -- SonnyE (I suggest viewed in full screen)
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On Sat, Apr 25, 2020 at 11:48 AM, Brian Valente wrote:
well, we know you can plate solve, your camera, settings, and mount all checked out
?
so something must have changed :)
I agree. I stuck my dirty fingers where I shouldn't have. About the time I was trying to Polar Align with SharpCap, I think. I know I am my own worst enemy. I need to clean out a lot of programs I won't be using... Too much cyber trash, I fear. ? -- SonnyE (I suggest viewed in full screen)
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Yet another gotcha:
I often use a ZWO ASI120 camera for autoguiding.? The USB2 models are inexpensive and very sensitive.? ( USB3 ASI120 models do exist at higher cost.)
However, the USB2 version has a major problem: if you connect one of these USB2 ZWO cameras to a USB3 port:?
Watch out! The camera frame sometimes glitches.?
? PHD2 does not detect glitched frames, and falls out of autoguiding.? No idea why the frames glitch (same with Firecapture).? I must only connect that particular brand of USB2 camera only to a laptop USB2 port!? That glitching destroyed my PHD2 autoguiding ability three nights ago.
Last night went quite well. I took PE data...must boil that down.? ?I got to shoot M81, M51, and M15 for awhile. The sky was crummy all night but I needed the (equipment) exercise!
Stay well, all,
Michael
On Fri, Apr 24, 2020 at 04:01 PM, Michael Herman wrote:
My own gotcha the other night was:
?
My USB and dew heater cables somehow snagged and held back the mount tracking ... erratically.??
Me Too, Michael!
But mine was some errant slew. I was operating remote from my inside Box-O-Rocks. Suddenly it stopped slewing. I went out and found my harness wrapped around the Dec axis. Oy!
Come to think about it, maybe things have never really recovered from that?
I haven't done it, but maybe I need to format the SD card, then reset it to factory original. Pretty harsh, but I haven'y gone that deep before, yet.
With my old mount, my harness exited down the CW shaft. That way it was controlled by the motions the mount took. Radical approach, but it worked. And a "drip Loop" with a Ball Bungee mount at the accessory tray.
I'm considering using some ball bungee attachments to allow more flexibility.?
Being at the mount is one thing, I can watch it.
But being remote like I do is quite another.
Never a dull moment in this sport. LOL!
Okay, back to that guy in the mirror. I think he causes me no end to grief.
LOL!
?
--
SonnyE
(I suggest viewed in full screen)
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I have heard a number of issues regarding the "earlier" ASI120 model, loads of them in the PHD forums
i try to steer clear of that particular mode
I think michael is right, the newer version seems to resolve this issue, but at higher cost)
On Sat, Apr 25, 2020 at 12:50 PM Michael Herman < mherman346@...> wrote: Yet another gotcha:
I often use a ZWO ASI120 camera for autoguiding.? The USB2 models are inexpensive and very sensitive.? ( USB3 ASI120 models do exist at higher cost.)
However, the USB2 version has a major problem: if you connect one of these USB2 ZWO cameras to a USB3 port:?
Watch out! The camera frame sometimes glitches.?
? PHD2 does not detect glitched frames, and falls out of autoguiding.? No idea why the frames glitch (same with Firecapture).? I must only connect that particular brand of USB2 camera only to a laptop USB2 port!? That glitching destroyed my PHD2 autoguiding ability three nights ago.
Last night went quite well. I took PE data...must boil that down.? ?I got to shoot M81, M51, and M15 for awhile. The sky was crummy all night but I needed the (equipment) exercise!
Stay well, all,
Michael
On Fri, Apr 24, 2020 at 04:01 PM, Michael Herman wrote:
My own gotcha the other night was:
?
My USB and dew heater cables somehow snagged and held back the mount tracking ... erratically.??
Me Too, Michael!
But mine was some errant slew. I was operating remote from my inside Box-O-Rocks. Suddenly it stopped slewing. I went out and found my harness wrapped around the Dec axis. Oy!
Come to think about it, maybe things have never really recovered from that?
I haven't done it, but maybe I need to format the SD card, then reset it to factory original. Pretty harsh, but I haven'y gone that deep before, yet.
With my old mount, my harness exited down the CW shaft. That way it was controlled by the motions the mount took. Radical approach, but it worked. And a "drip Loop" with a Ball Bungee mount at the accessory tray.
I'm considering using some ball bungee attachments to allow more flexibility.?
Being at the mount is one thing, I can watch it.
But being remote like I do is quite another.
Never a dull moment in this sport. LOL!
Okay, back to that guy in the mirror. I think he causes me no end to grief.
LOL!
?
--
SonnyE
(I suggest viewed in full screen)
-- Brian?
Brian Valente portfolio
|
Wow, went OT pretty quickly here, but just to get back to the original topic, I've now done everything possible to remedy any pointing issues, eliminating any possible cause of flexure in my optical train, checking to make sure clutches and gears are all tight (they are - after hours of use, the mount returns to the exact CWD position in which it started), checking balance, parameters, etc.? Pointing last night was a little better at first, but eventually got off course again, and I had to readjust to get my imaging targets centered.
Last night, my first alignment star was Alphard, then Procyon, then Betelgeuse in the West.? I then slewed to Arcturus in the East.? Since Scott's video says that's enough to be aligned, I left it at that.? Slewed to Sirius and it did pretty well.? But when I then slewed back to Arcturus, the pointing was so-so.? After doing my first image (the Coma cluster), I slewed to Spica to test the pointing and also re-focus, and it was off about the amount that it's "normally" off-target.? So I did the "alignment" star routine, then slewed down to omega Centauri, which was not well-centered.
The mount seems to track ok once I'm on the target, but still the pointing issue remains.? I'm going to try one more thing - entering seconds for latitude and longitude into the computer? (don't understand why that can't be done on the hand controller).
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followup questions for you:
Can you be more specific when you say the pointing is off - is it off by how much, and is it always off in?one particular direction?
have you been checking your model parameters as you go along? they are available on the gemini web page
how is your polar alignment? that can be a big factor as well
If your pointing is good and then gets worse, something is being added to the pointing model that degrades it: a bad alignment typically.?
Wow, went OT pretty quickly here, but just to get back to the original topic, I've now done everything possible to remedy any pointing issues, eliminating any possible cause of flexure in my optical train, checking to make sure clutches and gears are all tight (they are - after hours of use, the mount returns to the exact CWD position in which it started), checking balance, parameters, etc.? Pointing last night was a little better at first, but eventually got off course again, and I had to readjust to get my imaging targets centered.
Last night, my first alignment star was Alphard, then Procyon, then Betelgeuse in the West.? I then slewed to Arcturus in the East.? Since Scott's video says that's enough to be aligned, I left it at that.? Slewed to Sirius and it did pretty well.? But when I then slewed back to Arcturus, the pointing was so-so.? After doing my first image (the Coma cluster), I slewed to Spica to test the pointing and also re-focus, and it was off about the amount that it's "normally" off-target.? So I did the "alignment" star routine, then slewed down to omega Centauri, which was not well-centered.
The mount seems to track ok once I'm on the target, but still the pointing issue remains.? I'm going to try one more thing - entering seconds for latitude and longitude into the computer? (don't understand why that can't be done on the hand controller).
-- Brian?
Brian Valente portfolio
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Hi Brian,
I do appreciate your responses, but may I ask if you work for Losmandy?? Not getting defensive here, it's just that you seem to be on the defense for them!? Not all issues are user-caused, as I'm sure you know, and I'm trying to eliminate as much of that possibility as I can.? My polar alignment is perfect.? I use a Polemaster, and it's dead-on.? As I've always understood it, "close enough" should be good enough because the computer model should compensate for it.? But I'm not happy with "close enough."? The mount is also level.
Could you suggest please what it is that I might be "adding" to the pointing model?? And is it not true that adding alignment stars is supposed to refine pointing ability?? That is not happening.? I choose Menu > Align > Bright Star > Align > Alignment.? Isn't that supposed to refine the pointing capability?? As far as flexure, I have a Tele Vue NP127is.? The 2.4" focuser in that is rock solid.? I'm using a few short threaded couplings between that and my Nikon D5300, then I use the D5300 live screen to point and center.? It has a handy small red square in the center, with a red dot in the center of that.? I in-focus so stars are slightly out of focus and fit nicely into that square and I can see they're properly centered.? Has worked well for me for years now.? So, to give an example, let's say I get my model configured and I then focus on Arcturus using a Bahtinov mask, and it's right in the center of that red dot.? Then I'll slew to Spica, and Spica is completely outside of the red box, not even near the red center dot.? I realize no mount is going to have perfect pointing, but to me that's unacceptable.
The amount it's off varies, as does the direction.? I've had cases where I refine the alignment on one star, and the next isn't even in the field (example, say, Spica, then on to Dubhe, or Mizar).? And it's not the refining that's the cause, because I've had pointing issues whether or not I use additional alignment stars.? I'm going to keep playing with ideas.? Maybe do three alignment stars on each side of the meridian, instead of three on one and one on the other.? I have tried that and it didn't work, but I'll try it again now that I've checked other variables.
Thanks,
John
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HI John
>>I do appreciate your responses, but may I ask if you work for Losmandy?? Not getting defensive here, it's just that you seem to be on the defense for them!?
i do. and I apologize if this comes across as defensive. My questions are not meant to suggest you are doing anything incorrect, or you are the problem, they are to eliminate the obvious things that can and do go wrong.
My suggestions are unrelated to me working at losmandy, but if you wrote to losmandy tech support, these are exactly the questions I would ask. It's a challenge \to diagnose an issue without actually being there, so you have to ask all the questions.?
Pointing models and building?them really don't change: sidereal rate is the same, the position of the stars are (mostly) the same, the pointing model building procedure is the same. So figuring out what is different for you is the trick, right?? ?
Brian
Hi Brian,
I do appreciate your responses, but may I ask if you work for Losmandy?? Not getting defensive here, it's just that you seem to be on the defense for them!? Not all issues are user-caused, as I'm sure you know, and I'm trying to eliminate as much of that possibility as I can.? My polar alignment is perfect.? I use a Polemaster, and it's dead-on.? As I've always understood it, "close enough" should be good enough because the computer model should compensate for it.? But I'm not happy with "close enough."? The mount is also level.
Could you suggest please what it is that I might be "adding" to the pointing model?? And is it not true that adding alignment stars is supposed to refine pointing ability?? That is not happening.? I choose Menu > Align > Bright Star > Align > Alignment.? Isn't that supposed to refine the pointing capability?? As far as flexure, I have a Tele Vue NP127is.? The 2.4" focuser in that is rock solid.? I'm using a few short threaded couplings between that and my Nikon D5300, then I use the D5300 live screen to point and center.? It has a handy small red square in the center, with a red dot in the center of that.? I in-focus so stars are slightly out of focus and fit nicely into that square and I can see they're properly centered.? Has worked well for me for years now.? So, to give an example, let's say I get my model configured and I then focus on Arcturus using a Bahtinov mask, and it's right in the center of that red dot.? Then I'll slew to Spica, and Spica is completely outside of the red box, not even near the red center dot.? I realize no mount is going to have perfect pointing, but to me that's unacceptable.
The amount it's off varies, as does the direction.? I've had cases where I refine the alignment on one star, and the next isn't even in the field (example, say, Spica, then on to Dubhe, or Mizar).? And it's not the refining that's the cause, because I've had pointing issues whether or not I use additional alignment stars.? I'm going to keep playing with ideas.? Maybe do three alignment stars on each side of the meridian, instead of three on one and one on the other.? I have tried that and it didn't work, but I'll try it again now that I've checked other variables.
Thanks,
John
-- Brian?
Brian Valente portfolio
|
Have you checked that you clutches are reasonably tight?? No cable drag? This feels like a mechanical problem ¨C once you¡¯ve been somewhere you should be able to return (unless you have synched on another object that wasn¡¯t initially dead centre in which case all bets are off). ? David ?
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From: [email protected] [mailto:[email protected]] On Behalf Of astroitalian@...
Sent: 27 April 2020 16:40
To: [email protected]
Subject: Re: [Losmandy_users_io] Pointing Issues ? Hi Brian,
I do appreciate your responses, but may I ask if you work for Losmandy?? Not getting defensive here, it's just that you seem to be on the defense for them!? Not all issues are user-caused, as I'm sure you know, and I'm trying to eliminate as much of that possibility as I can.? My polar alignment is perfect.? I use a Polemaster, and it's dead-on.? As I've always understood it, "close enough" should be good enough because the computer model should compensate for it.? But I'm not happy with "close enough."? The mount is also level.
Could you suggest please what it is that I might be "adding" to the pointing model?? And is it not true that adding alignment stars is supposed to refine pointing ability?? That is not happening.? I choose Menu > Align > Bright Star > Align > Alignment.? Isn't that supposed to refine the pointing capability?? As far as flexure, I have a Tele Vue NP127is.? The 2.4" focuser in that is rock solid.? I'm using a few short threaded couplings between that and my Nikon D5300, then I use the D5300 live screen to point and center.? It has a handy small red square in the center, with a red dot in the center of that.? I in-focus so stars are slightly out of focus and fit nicely into that square and I can see they're properly centered.? Has worked well for me for years now.? So, to give an example, let's say I get my model configured and I then focus on Arcturus using a Bahtinov mask, and it's right in the center of that red dot.? Then I'll slew to Spica, and Spica is completely outside of the red box, not even near the red center dot.? I realize no mount is going to have perfect pointing, but to me that's unacceptable.
The amount it's off varies, as does the direction.? I've had cases where I refine the alignment on one star, and the next isn't even in the field (example, say, Spica, then on to Dubhe, or Mizar).? And it's not the refining that's the cause, because I've had pointing issues whether or not I use additional alignment stars.? I'm going to keep playing with ideas.? Maybe do three alignment stars on each side of the meridian, instead of three on one and one on the other.? I have tried that and it didn't work, but I'll try it again now that I've checked other variables.
Thanks,
John
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Hey John,
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First things first, I do not work for Losmandy. I am a new owner, since 1 and a half year.
I feel for you, I have encountered strange and similar issues Magnus also encountered about the same time.
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Sometimes it worked nicely, sometimes it went crazy. I could not get good guiding. I also encountered runaways, but rare, only during meridian flips or SGP slews. This is a documented problem that is addressed by the beta firmware available.
I went ape nuts not being able to understand and get the accuracy I was expecting.
- I tried dampening solutions. Like pads or I "temporarily" modified the terrace of the apartment I rent (pictures upon request).
- I did 3 axis balancing.
- I designed my own custom RA passthrough cable solution to eliminate drag (pictures upon request).
- Top notch polar alignment, I am sorry to say but you can get much much better PA than with polarscope, it is unfortunately not as precise at it reports it is. For instance, SharpCap is a cheap alternative with same time to get aligned, or PHD2 using drift align but while being to most precise that will take longer 15-30min...
- I reduced focuser vibrations with a second custom designed mounting bracket.
- I started tuning/messing my spring-loaded worm gear adjustments.
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If you're interested my issues were related to balancing, using a camera lens causing tremendous chromatic aberrations leading to bad eccentricity no matter what, bad tuning of the SLWG, BAD tightening of the clutches, grease contamination on my DEC clutch pad, bad understanding of measuring error in PHD2.
I am saying this because I have eventually fixed my issues. And that was thanks to this community driven website. Which is not sponsored by Losmandy in anyways.
It is a mine of useful information and years of experience from all its users. Brian was here long before he was hired and has always been a major contributor.
?
My message is I know it is frustrating but please be attentive to advises given here, they worth GOLD and they will get you were you want.
Also be patient, none are paid but Brian, rather please be thankful a Losmandy staff is here, because he responds much faster than anyone else here, even on weekends ;-)
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Good luck you'll get it right.
Never forget that you paid half the price of a scientific mount that will work out of the box but will require expensive maintenance through time. It is hard, but you'll master and understand your mount.
To me this has no price!
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Cheers,
?
Carl
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Thanks to all, and Brian, I'm actually GLAD to hear you work for Losmandy.? I was just wondering.? And naturally you're going to want to defend the product, but I want you to know, and I think I've said it already, that I think the mount is a work of machining art.? I worked for a high-end custom telescope manufacturer for a few years, and we had a machinist who was a perfectionist, and used Byers gears, etc.? I know what good machinery is.? I like the Losmandy GM811G.? Problem is, I want to LOVE it, not just like it!? And I think I'm on the way.? My wife and I (I'm the astro tech savvy one, while she's more computer savvy) found something that may well have been causing the pointing glitch.? We're both not quite sure how to explain it in words, but I am hoping to get out tonight, see if it remedied the issue, and then I'll get back with you tomorrow and let you know.? And yes, it would be user error, but not something easily diagnosed.
To respond to David and Carl, I think I've covered the bases you mention.? Only cord coming off the OTA for now is the guide scope, plugged into a USB hub attached to one leg of the LW tripod.? I've configured it so there's virtually no drag from that.? I do not use a polar scope, but rather Polemaster (ok, I guess that's kind of a polar scope) and don't ever recall anyone being unhappy with their polar alignment, properly done, using one of those? Next on my list is figuring out how to use plate solving.? I'm an old guy, slowly learning new tricks.
When I installed the large wavy washer to remedy a tight RA axis, I cleaned all surfaces with rubbing alcohol, so no slippage there.? As for the clutches, I'm tightening them up pretty good now.? "How much" was a bit of a learning process, and the Dec axis was slipping some, as I might have mentioned.
As for tracking, that seems to be working pretty well overall, and I'm real happy about that.? Doing 3-minute subs in so-so seeing with good, round stars.? I applied PHD's PPEC and that helped too.? The other night I was getting .6-.7 RMS, though not consistently, possibly, again, due to changes in seeing.
So, thanks all, and I hope I've conveyed my appreciation that this discussion board is here and I also hope that eventually I can be a help to others who might encounter problems.? Nor am I here to complain, but to learn, sometimes from mistakes.? No mount or guiding system is perfect, and I appreciate the genius that goes into both the physical hardware and the controlling software, and would never criticize it as being sub par, unless I thought I could do it better, and I can't.? It's like a quote from Sylvester Stallone that I've always loved.? He is a classical art collector.? When asked his opinion of some modern art, his response was, "If I think I could do it better, I don't buy it."
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Hello John, I have a very similar problem. It is like my Gemini 2 console box is not set for a G11 but a Titan. My goto's slew past the target. Like I am a hour or so off. When I first got my G11 last Christmas it was amazingly accurate. Now
it is in the neighborhood but not close. I spent a few hours trying different timezone settings and? time settings,this should have been able to be seen in the slewing positions, it should have been dramatic in where the mount slews to, nope no change. The
one star it will go to is Polaris. And it tracks well so I know that the mount itself is working fine, the Gemini 2 has issues and or the handset. I tried different start ups Quick Start, Cold Start, new batteries changing RA and DEC cables
Resetting up from the beginning. I thought hmm what if I? did not align on Polaris. Yes I did, so that was not the issue.
I will send my Gemini 2 hand handset back to Losmandy this week.
This is not a reflection on Losmandy or their products in any way. These things happen.
I had a talk with Losmandy today, She was very nice and easy to deal with.
I will get through this and so will you John.
HAPPY SKIES Deric
Sent from my Galaxy Tab A
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-------- Original message --------
From: astroitalian@...
Date: 4/27/20 10:39 AM (GMT-06:00)
Subject: Re: [Losmandy_users_io] Pointing Issues
Hi Brian,
I do appreciate your responses, but may I ask if you work for Losmandy?? Not getting defensive here, it's just that you seem to be on the defense for them!? Not all issues are user-caused, as I'm sure you know, and I'm trying to eliminate as much of that possibility
as I can.? My polar alignment is perfect.? I use a Polemaster, and it's dead-on.? As I've always understood it, "close enough" should be good enough because the computer model should compensate for it.? But I'm not happy with "close enough."? The mount is
also level.
Could you suggest please what it is that I might be "adding" to the pointing model?? And is it not true that adding alignment stars is supposed to refine pointing ability?? That is not happening.? I choose Menu > Align > Bright Star > Align > Alignment.? Isn't
that supposed to refine the pointing capability?? As far as flexure, I have a Tele Vue NP127is.? The 2.4" focuser in that is rock solid.? I'm using a few short threaded couplings between that and my Nikon D5300, then I use the D5300 live screen to point and
center.? It has a handy small red square in the center, with a red dot in the center of that.? I in-focus so stars are slightly out of focus and fit nicely into that square and I can see they're properly centered.? Has worked well for me for years now.? So,
to give an example, let's say I get my model configured and I then focus on Arcturus using a Bahtinov mask, and it's right in the center of that red dot.? Then I'll slew to Spica, and Spica is completely outside of the red box, not even near the red center
dot.? I realize no mount is going to have perfect pointing, but to me that's unacceptable.
The amount it's off varies, as does the direction.? I've had cases where I refine the alignment on one star, and the next isn't even in the field (example, say, Spica, then on to Dubhe, or Mizar).? And it's not the refining that's the cause, because I've had
pointing issues whether or not I use additional alignment stars.? I'm going to keep playing with ideas.? Maybe do three alignment stars on each side of the meridian, instead of three on one and one on the other.? I have tried that and it didn't work, but I'll
try it again now that I've checked other variables.
Thanks,
John
|
Hi Deric
just curious - do you use polaris for an alignment point?
Hello John, I have a very similar problem. It is like my Gemini 2 console box is not set for a G11 but a Titan. My goto's slew past the target. Like I am a hour or so off. When I first got my G11 last Christmas it was amazingly accurate. Now
it is in the neighborhood but not close. I spent a few hours trying different timezone settings and? time settings,this should have been able to be seen in the slewing positions, it should have been dramatic in where the mount slews to, nope no change. The
one star it will go to is Polaris. And it tracks well so I know that the mount itself is working fine, the Gemini 2 has issues and or the handset. I tried different start ups Quick Start, Cold Start, new batteries changing RA and DEC cables
Resetting up from the beginning. I thought hmm what if I? did not align on Polaris. Yes I did, so that was not the issue.
I will send my Gemini 2 hand handset back to Losmandy this week.
This is not a reflection on Losmandy or their products in any way. These things happen.
I had a talk with Losmandy today, She was very nice and easy to deal with.
I will get through this and so will you John.
HAPPY SKIES Deric
Sent from my Galaxy Tab A
-------- Original message --------
Date: 4/27/20 10:39 AM (GMT-06:00)
Subject: Re: [Losmandy_users_io] Pointing Issues
Hi Brian,
I do appreciate your responses, but may I ask if you work for Losmandy?? Not getting defensive here, it's just that you seem to be on the defense for them!? Not all issues are user-caused, as I'm sure you know, and I'm trying to eliminate as much of that possibility
as I can.? My polar alignment is perfect.? I use a Polemaster, and it's dead-on.? As I've always understood it, "close enough" should be good enough because the computer model should compensate for it.? But I'm not happy with "close enough."? The mount is
also level.
Could you suggest please what it is that I might be "adding" to the pointing model?? And is it not true that adding alignment stars is supposed to refine pointing ability?? That is not happening.? I choose Menu > Align > Bright Star > Align > Alignment.? Isn't
that supposed to refine the pointing capability?? As far as flexure, I have a Tele Vue NP127is.? The 2.4" focuser in that is rock solid.? I'm using a few short threaded couplings between that and my Nikon D5300, then I use the D5300 live screen to point and
center.? It has a handy small red square in the center, with a red dot in the center of that.? I in-focus so stars are slightly out of focus and fit nicely into that square and I can see they're properly centered.? Has worked well for me for years now.? So,
to give an example, let's say I get my model configured and I then focus on Arcturus using a Bahtinov mask, and it's right in the center of that red dot.? Then I'll slew to Spica, and Spica is completely outside of the red box, not even near the red center
dot.? I realize no mount is going to have perfect pointing, but to me that's unacceptable.
The amount it's off varies, as does the direction.? I've had cases where I refine the alignment on one star, and the next isn't even in the field (example, say, Spica, then on to Dubhe, or Mizar).? And it's not the refining that's the cause, because I've had
pointing issues whether or not I use additional alignment stars.? I'm going to keep playing with ideas.? Maybe do three alignment stars on each side of the meridian, instead of three on one and one on the other.? I have tried that and it didn't work, but I'll
try it again now that I've checked other variables.
Thanks,
John
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