Without any changes on my mount NINA report the following PA error:
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I think I asked the question in a post a few months back "How do we measure PA objectively to gauge the performance of the different tools/software". Ultimately, measuring drift, seemed to be that method, but I still didn't get a great answer. All the tools seem to disagree. SC vs Nina TPPA vs iPolar vs Polemaster.
I suffer from an extreme lack of clear skies combined with a condition called kids-never-go-to-bed-itis, but someone with some extra nights to spare could make a great video comparing these with some real masurements.
@Christian Bennich you are pretty much half way there already ;-)
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What I think better to follow is that ..
How is your guiding? > How are your stars?
If they are good.. keep going with the same prog. you used.. SC, NINA or polemaster...etc.
I think its so difficult to get same result with two different prog.
personally I suffered from these measurements differences .. at last I make my decision to "SEE YOUR STARS" method and I am cured now 
CS!
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Nick Grundy:
I think I asked the question in a post a few months back "How do we measure PA objectively to gauge the performance of the different tools/software". Ultimately, measuring drift, seemed to be that method, but I still didn't get a great answer. All the tools seem to disagree. SC vs Nina TPPA vs iPolar vs Polemaster.
I suffer from an extreme lack of clear skies combined with a condition called kids-never-go-to-bed-itis, but someone with some extra nights to spare could make a great video comparing these with some real masurements.
@Christian Bennich you are pretty much half way there already ;-)
HAHA, True 
However, maybe the answer is that "there is no real answer". I watched Bruce Waddington, one of the skilled PHD2 devs, on this youtube video - https://www.youtube.com/watch?v=ty8hukjAPMw - in this video he says, as I understand it, that if you can get your polar alignment down under ~5' you should be fine, then autoguiding can "take it from there".
If you don't want to watch the entire video - which by the way, is excellent - then fast forward to 1:04:54 ish - and watch from there.
Based on his input from the video, I honestly don't think there will be any huge difference between one or the other piece of software and at the end of it all, we still rely on ourselves to "finetune" our mount, which is definitely not an exact science I would argue.
Based on my last couple of nights of messing around with guiding on my particular setup, I think I would agree with @Ali Alhawas - if your result looks good - you're good. (unless you are aiming for pixel perfection - with my average seeing, 2"-4" at best - I think I might be chasing diminishing returns here.)
I got 0.55" guiding last night at best, and also found that choosing better guidestars made a huge difference as well. I was imaging in the Coma Cluster - not too many stars for my OAG - and PHD2 seemed to pick distant galaxies for stars, but handpicking a better star in this particular area of the sky was what worked for me last night.
There might be options in PHD2 to make it better at choosing higher SNR stars or something - which I will check out - and if anyone knows already, feel free to share your knowledge.
@Nick Grundy - when I "grow up" I wan't to be a famous Astro YouTuber though  |
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Christian Bennich:
got 0.55" guiding last night at best, and also found that choosing better guidestars made a huge difference as well.
since, I'm not grown up yet, there's still hope!
one of the few tweaks I've made that were extremeley noticeable in guiding came from one of @John Hayes videos on long focal length guiding. I added 5kg counterweight, which allowed me to move the whole cw stack up much closer to the axis. Despite objections from poor seeing nights, I'm fairly certain that shaved .1 rms off my ra averages.
I also have to agree with Ali and what most say, if the stars look good, it's going well.
and then the internal engineer wants something to tinker with :-)
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Nick Grundy:
Christian Bennich:
got 0.55" guiding last night at best, and also found that choosing better guidestars made a huge difference as well.
I added 5kg counterweight, which allowed me to move the whole cw stack up much closer to the axis.
Good point!!!!
That is actually one if the things I also did, but COMPLETELY forgot to mention.
I’m running 3x5kg - it might be worth testing with an additional cw - to move the centre of mass even closer to the axis.
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Adding extra counter weight is in fact useful. I did this for both my EQ6s. Two 11 pounders and a 5 pounder each. Actual RMS didn't improve substantially, but the spikes did in fact. It was much more reliable guiding. This is why anytime I see someone with extension bars I kinda cringe lol.
Your polar alignment test is pretty much in line with what I've seen. The best measurement for polar alignment is simply drift measurement, like your guiding assistant did. For lighter mounts like the EQ6, PEC error will usually affect guiding alot more than a little bit of misalignment will, that's why we get away with imperfect polar alignment. It's when you get to the big Mounts and longer focal lengths that it really matters.
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a little hard work really does make a difference 
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What did you change in order to get there?
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So, I worked on my Polar Alignment, checked and perfected the balance of my scope, restrapped all cabling on my scooe to minimize any options for cable snagging or any strange pulling from cable weight in any direction, made sure that the guide calibration was good, implemented all input from PHD2, changed my RA algorithm to Predictive PEC and finally added additional counterweight for a total of 20kg - allowing me to move the weight as close as possible to the axis.
I think that was it 👍
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Brian Puhl:
Eddie Bagwell:
Brian Puhl:
Sounds to me like your guide rate is possibly too low, or you have a balance/snag issue. Option 3 is large backlash.
Could be the guide rate too low, I changed it to .8 and PHD2 keeps automatically changing it back to .5. There are no balance or snag issues, and backlash seems to be minimal but there.
I had a difficult time setting up PHD2 a couple of years ago but after getting all of the settings ironed out, I haven't had any problems with guiding since.
Any backlash in RA is kinda bad. You can get away with it in dec kinda. I use 0.5 guide rate as well, so that sounds fine.
This is completely the wrong, you have it the way round, backlash in RA does not really matter at that axis never changes direction, it just speeds up or slows down, it’s bad when it’s on the DEC axis….as this can change direction a lot depending on PA and so lash here should be eliminated if possible….
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AstroShed:
Brian Puhl:
Eddie Bagwell:
Brian Puhl:
Sounds to me like your guide rate is possibly too low, or you have a balance/snag issue. Option 3 is large backlash.
Could be the guide rate too low, I changed it to .8 and PHD2 keeps automatically changing it back to .5. There are no balance or snag issues, and backlash seems to be minimal but there.
I had a difficult time setting up PHD2 a couple of years ago but after getting all of the settings ironed out, I haven't had any problems with guiding since.
Any backlash in RA is kinda bad. You can get away with it in dec kinda. I use 0.5 guide rate as well, so that sounds fine.
This is completely the wrong, you have it the way round, backlash in RA does not really matter at that axis never changes direction, it just speeds up or slows down, it’s bad when it’s on the DEC axis….as this can change direction a lot depending on PA and so lash here should be eliminated if possible….
Declination backlash can be corrected/band aided for by setting Dec to correct only one direction, which will account for polar alignment error. It should not be bouncing back and forth as you speak save for really bad nights of seeing. If it is, you should consider relaxing your minimum move.
You can't do things like this in RA because of periodic error.
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Nick Grundy:
Christian Bennich:
got 0.55" guiding last night at best, and also found that choosing better guidestars made a huge difference as well.
since, I'm not grown up yet, there's still hope!
one of the few tweaks I've made that were extremeley noticeable in guiding came from one of @John Hayes videos on long focal length guiding. I added 5kg counterweight, which allowed me to move the whole cw stack up much closer to the axis. Despite objections from poor seeing nights, I'm fairly certain that shaved .1 rms off my ra averages.
I also have to agree with Ali and what most say, if the stars look good, it's going well.
and then the internal engineer wants something to tinker with :-)
I'm a noob, so apologies, but I use one large cw quite near the end of my cw er stick. Should I try adding the spare smaller cw too and move them both up the stick? (Sorry not sure of the technical terms).
My mount payload supposed to be 5kg and I'm maybe at about 2.5kg total excluding cw
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TiffsAndAstro:
Nick Grundy:
Christian Bennich:
got 0.55" guiding last night at best, and also found that choosing better guidestars made a huge difference as well.
since, I'm not grown up yet, there's still hope!
one of the few tweaks I've made that were extremeley noticeable in guiding came from one of @John Hayes videos on long focal length guiding. I added 5kg counterweight, which allowed me to move the whole cw stack up much closer to the axis. Despite objections from poor seeing nights, I'm fairly certain that shaved .1 rms off my ra averages.
I also have to agree with Ali and what most say, if the stars look good, it's going well.
and then the internal engineer wants something to tinker with :-)
I'm a noob, so apologies, but I use one large cw quite near the end of my cw er stick. Should I try adding the spare smaller cw too and move them both up the stick? (Sorry not sure of the technical terms).
My mount payload supposed to be 5kg and I'm maybe at about 2.5kg total excluding cw
In my scenario it helped calm my RA a bit more.
I would argue, without knowing how your situation looks and what guiding issues you might have, it’s difficult to give any clear and specific guidance.
For me it was the “last” thing I changed - not the first 🤷♂️
Try it out - if it works, it works. If not, take it off again.
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Brian Puhl:
AstroShed:
Brian Puhl:
Eddie Bagwell:
Brian Puhl:
Sounds to me like your guide rate is possibly too low, or you have a balance/snag issue. Option 3 is large backlash.
Could be the guide rate too low, I changed it to .8 and PHD2 keeps automatically changing it back to .5. There are no balance or snag issues, and backlash seems to be minimal but there.
I had a difficult time setting up PHD2 a couple of years ago but after getting all of the settings ironed out, I haven't had any problems with guiding since.
Any backlash in RA is kinda bad. You can get away with it in dec kinda. I use 0.5 guide rate as well, so that sounds fine.
This is completely the wrong, you have it the way round, backlash in RA does not really matter at that axis never changes direction, it just speeds up or slows down, it’s bad when it’s on the DEC axis….as this can change direction a lot depending on PA and so lash here should be eliminated if possible….
Declination backlash can be corrected/band aided for by setting Dec to correct only one direction, which will account for polar alignment error. It should not be bouncing back and forth as you speak save for really bad nights of seeing. If it is, you should consider relaxing your minimum move.
You can't do things like this in RA because of periodic error.
That’s all well and good, but not good practice at all, plus you can’t dither properly either, you are better to sort out the lash rather than trying to put a bandaid on it. At the end of the day the RA can cope with lash, for the reason I explined, but the DEC should not have to….simple
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Christian Bennich:
TiffsAndAstro:
Nick Grundy:
Christian Bennich:
got 0.55" guiding last night at best, and also found that choosing better guidestars made a huge difference as well.
since, I'm not grown up yet, there's still hope!
one of the few tweaks I've made that were extremeley noticeable in guiding came from one of @John Hayes videos on long focal length guiding. I added 5kg counterweight, which allowed me to move the whole cw stack up much closer to the axis. Despite objections from poor seeing nights, I'm fairly certain that shaved .1 rms off my ra averages.
I also have to agree with Ali and what most say, if the stars look good, it's going well.
and then the internal engineer wants something to tinker with :-)
I'm a noob, so apologies, but I use one large cw quite near the end of my cw er stick. Should I try adding the spare smaller cw too and move them both up the stick? (Sorry not sure of the technical terms).
My mount payload supposed to be 5kg and I'm maybe at about 2.5kg total excluding cw
In my scenario it helped calm my RA a bit more.
I would argue, without knowing how your situation looks and what guiding issues you might have, it’s difficult to give any clear and specific guidance.
For me it was the “last” thing I changed - not the first 🤷♂️
Try it out - if it works, it works. If not, take it off again.
You should always where possible have the weights as close to the mount head as possible and add more weight if needed, as it reduces the moment arm and takes load off the gears and motor, and will help the mount and should guide better too…it’s just good practice…👍🏻
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AstroShed:
Christian Bennich:
TiffsAndAstro:
Nick Grundy:
Christian Bennich:
got 0.55" guiding last night at best, and also found that choosing better guidestars made a huge difference as well.
since, I'm not grown up yet, there's still hope!
one of the few tweaks I've made that were extremeley noticeable in guiding came from one of @John Hayes videos on long focal length guiding. I added 5kg counterweight, which allowed me to move the whole cw stack up much closer to the axis. Despite objections from poor seeing nights, I'm fairly certain that shaved .1 rms off my ra averages.
I also have to agree with Ali and what most say, if the stars look good, it's going well.
and then the internal engineer wants something to tinker with :-)
I'm a noob, so apologies, but I use one large cw quite near the end of my cw er stick. Should I try adding the spare smaller cw too and move them both up the stick? (Sorry not sure of the technical terms).
My mount payload supposed to be 5kg and I'm maybe at about 2.5kg total excluding cw
In my scenario it helped calm my RA a bit more.
I would argue, without knowing how your situation looks and what guiding issues you might have, it’s difficult to give any clear and specific guidance.
For me it was the “last” thing I changed - not the first 🤷♂️
Try it out - if it works, it works. If not, take it off again.
You should always where possible have the weights as close to the mount head as possible and add more weight if needed, as it reduces the moment arm and takes load off the gears and motor, and will help the mount and should guide better too…it’s just good practice…👍🏻
surely the moment arm of cw equal the moment arm of the payload? Mass x distance?
But more cw closer just means more mass?
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TiffsAndAstro:
AstroShed:
Christian Bennich:
TiffsAndAstro:
Nick Grundy:
Christian Bennich:
got 0.55" guiding last night at best, and also found that choosing better guidestars made a huge difference as well.
since, I'm not grown up yet, there's still hope!
one of the few tweaks I've made that were extremeley noticeable in guiding came from one of @John Hayes videos on long focal length guiding. I added 5kg counterweight, which allowed me to move the whole cw stack up much closer to the axis. Despite objections from poor seeing nights, I'm fairly certain that shaved .1 rms off my ra averages.
I also have to agree with Ali and what most say, if the stars look good, it's going well.
and then the internal engineer wants something to tinker with :-)
I'm a noob, so apologies, but I use one large cw quite near the end of my cw er stick. Should I try adding the spare smaller cw too and move them both up the stick? (Sorry not sure of the technical terms).
My mount payload supposed to be 5kg and I'm maybe at about 2.5kg total excluding cw
In my scenario it helped calm my RA a bit more.
I would argue, without knowing how your situation looks and what guiding issues you might have, it’s difficult to give any clear and specific guidance.
For me it was the “last” thing I changed - not the first 🤷♂️
Try it out - if it works, it works. If not, take it off again.
You should always where possible have the weights as close to the mount head as possible and add more weight if needed, as it reduces the moment arm and takes load off the gears and motor, and will help the mount and should guide better too…it’s just good practice…👍🏻
surely the moment arm of cw equal the moment arm of the payload? Mass x distance?
But more cw closer just means more mass?
More weight closer to the mount is always better, it’s well documented…it takes less inertia to move the mount if set up this way, and helps in several ways….
yes it means more weight on the counter weight side, but it’s far better than having a smaller weight much farther from the mount head, ideally you want the pivot point of the mount (the RA axis) bang in the middle of the load and the CW, I see some mounts where the one little 5kg weight is at the bottom of the CW shaft, and yes it may well balance the load, but it does the gears and motors no good at all.
try it and see the difference, I have a 12kg set up and have 18kg of CW right up against my mount head in my CEM70, and it works really well, I could just have 12kg of CW further down the shaft, but this works perfectly well.
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TiffsAndAstro:
surely the moment arm of cw equal the moment arm of the payload? Mass x distance?
But more cw closer just means more mass?
If we're talking theory, I believe you are correct. it would be the same on a perfectly balanced arm. But back in reality, where my mount is definitely living, more weight + closer to axis = less torque required for the mount. In theory, you are also stressing the mechanical properties of the counterweight shaft less, and likely making the scope less susceptible to wind gusts?
Here's the link to John Hayes's presentation if you are interested https://www.advancedimagingconference.com/articles/secrets-long-focal-length-imaging-john-hayes I believe you need to sign up, but it's free.
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AstroShed:
TiffsAndAstro:
AstroShed:
Christian Bennich:
TiffsAndAstro:
Nick Grundy:
Christian Bennich:
got 0.55" guiding last night at best, and also found that choosing better guidestars made a huge difference as well.
since, I'm not grown up yet, there's still hope!
one of the few tweaks I've made that were extremeley noticeable in guiding came from one of @John Hayes videos on long focal length guiding. I added 5kg counterweight, which allowed me to move the whole cw stack up much closer to the axis. Despite objections from poor seeing nights, I'm fairly certain that shaved .1 rms off my ra averages.
I also have to agree with Ali and what most say, if the stars look good, it's going well.
and then the internal engineer wants something to tinker with :-)
I'm a noob, so apologies, but I use one large cw quite near the end of my cw er stick. Should I try adding the spare smaller cw too and move them both up the stick? (Sorry not sure of the technical terms).
My mount payload supposed to be 5kg and I'm maybe at about 2.5kg total excluding cw
In my scenario it helped calm my RA a bit more.
I would argue, without knowing how your situation looks and what guiding issues you might have, it’s difficult to give any clear and specific guidance.
For me it was the “last” thing I changed - not the first 🤷♂️
Try it out - if it works, it works. If not, take it off again.
You should always where possible have the weights as close to the mount head as possible and add more weight if needed, as it reduces the moment arm and takes load off the gears and motor, and will help the mount and should guide better too…it’s just good practice…👍🏻
surely the moment arm of cw equal the moment arm of the payload? Mass x distance?
But more cw closer just means more mass?
More weight closer to the mount is always better, it’s well documented…it takes less inertia to move the mount if set up this way, and helps in several ways….
yes it means more weight on the counter weight side, but it’s far better than having a smaller weight much farther from the mount head, ideally you want the pivot point of the mount (the RA axis) bang in the middle of the load and the CW, I see some mounts where the one little 5kg weight is at the bottom of the CW shaft, and yes it may well balance the load, but it does the gears and motors no good at all.
try it and see the difference, I have a 12kg set up and have 18kg of CW right up against my mount head in my CEM70, and it works really well, I could just have 12kg of CW further down the shaft, but this works perfectly well.
no harm me giving it a go, ty
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I able to shift one CW much closer to the mount (1 or 2 centimeters from having the edge of the CW actually hitting the mount itself), but the other CW now needs to go to the end of the shaft; will this modification still help my guiding?
(before, the CWs were about 1-2 inches from each other, nearer to the outer end of the shaft)
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will this modification still help my guiding?
good question, but I'm actually not sure. My suspicion is that you want them distributed evenly, though generally closer to the axis. Distributing them evenly (instead of 1 single point of load on the shaft) should help ease the torque required by the mount.
but someone with more physics knowledge should probably answer you.
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2.11
3.81
1.91
9.82
0.90
1.81
0.00
4.02
