HEQ5 3-star alignment - where did I go wrong?

[imakebeer]

I managed to get out for just an hour last night before the fog rolled in. This gave me a little bit of time to practice with my new-to-me HEQ5.....

(and to save you some time, please don't just tell me to polar align with Sharpcap - I'm working on this too, but I want to understand everything and not just skip to the answer)

I set up and got the tripod level (though in hindsight not as level as I perhaps thought) and pointed roughly at Polaris... I didn't use the Polarscope to get it bang on though as I understand this is kind of the point of 3 star alignment. I checked that the time and my local lat., long. and altitude in the handset were all correct.

Then I ran through the 3-star alignment using Capella, Mirach and Vega - this worked fine now that I've sussed you can alter the slewing speed 👍😁 I got all 3 stars dead-centre in the spotting scope first and then fine tuned through the eyepiece. I didn't have to do much adjustment, the software got me 98& of the way there each time and each star was already visible in the spotting scope, albeit off centre.

Once I was done with 3-star, I ran through the polar alignment which prompted me to adjust first the altitude bolts and then the azimuth bolts, which I did and got Vega dead centre in the eyepiece again.

Job's a goodun' , or so I thought, and figured righto, let's have a look at Mars - the scope slewed round but I found Mars was off to one side. Sure I can correct with the handset but after doing the alignment I expected Mars to be pretty much dead centre in the eyepiece. I double checked through the polarscope and Polaris was visible though well off centre and well outside the 0-3-6-9 clock circle.

So where am I going wrong? Have I got to get the tripod bang level at the start? Have I got to get Polaris bang on around the clock through the Polarscope? What else?

I finished the hour feeling like I had learned more than when I started so it was productive, but clearly there is still more I need to learn - just need a few more hours of clear skies! 👍🔭🤞

[Budgie1]

So, basically the routine is:

1. Get the tripod as level as you can. If you use the built-in level bubble then make sure it is actually level when the bubble is in the middle. Mine had been fitted into the tripod a little off level and checking with a spirit level across the top of tripod, with the mount removed, showed how far out it was. 
2. Do the Polar Alignment and use one of the free apps (I use one called Polar Clock for Android) to see where on the clock face in the polar scope Polaris needs to be on that night. This makes sure the mount's RA axis is correctly aligned with the Earths rotation.
3. Now the mount is Polar Aligned, run the 3-star alignment routine so the handset knows where the scope is pointing. The first one may be quite a way out, the second should be better and the third should be nearly spot-on. 

If it still shows quite an error after this, then re-check the tripod for level and the Polar Alignment, just to make sure nothing has moved. Even a slight kick of a tripod leg can be enough to cause alignment issues.  

[imakebeer]

Thanks @Budgie1, all clear, but...

9 minutes ago, Budgie1 said:

Do the Polar Alignment and use one of the free apps (I use one called Polar Clock for Android) to see where on the clock face in the polar scope Polaris needs to be on that night. This makes sure the mount's RA axis is correctly aligned with the Earths rotation.

No problem, I have about half a dozen of these apps on my phone now! 😂 I will absolutely go back out at the earliest opportunity and follow your advice, but...

...what I don't get is why this manual polar alignment is necessary? I mean, sure, if you're not using the handset or Sharpcap etc to do your alignment for you then absolutely I can see you need to align your mount manually like this - it's what I've been doing previously with my EQ1, albeit without a polarscope 😂 And I can certainly believe that if you take the time to get the manual polar alignment as good as possible in the beginning then you're making life easier for yourself later on.

But assuming you're not doing it manually then you do your 3 star alignment and then the option appears on the handset to do a polar alignment (there's a video here going through the complete process) - the latter prompts you to adjust first the altitude bolts, and then the azimuth bolts. And presumably the whole point of that final handset-guided polar alignment step is it's getting your RA axis bang on inline with the Earth's rotation (and as noted above my polar alignment was less wrong at the end than when I started!)

And even if anyone was inclined to tell me to "just use Sharpcap ,it's so much easier etc etc etc..." from what I see of the YouTube videos this method still requires you to adjust the alt. & az. bolts so is presumably doing something similar to the Synscan polar alignment???

Perhaps my tripod was too out of kilter or the mount too far away from Polaris to have worked at the first go. I did actually get the tripod more level and start the 3-star alignment again but alas was beaten by the fog ☹

[ONIKKINEN]

Dont worry about tripod leveling, it has 0 impact on any of this, unless you are setting up on a clear incline of 10 degrees or more. And in that case you could still polar align perfectly too, its just a tiny bit more tedious as adjusting altitude will also affect azimuth and vice versa so you have to fiddle. Forget the spirit levels and just eyeball the leveling to be ok.

If Polaris was outside the circle it means you were not polar aligned. When aligned Polaris should be on the circle (never in the center) no matter what orientation of RA you are in. I should note that the polar scope must be collimated for it to work since Skywatcher mounts are assembled with little care and they come out of the factory out of collimation.

Why the software method didnt work, couldnt tell you. You would need to keep doing the 3 star alignments to find out how much further adjustments are needed. Keep in mind that large amounts of cone error will complicate this step and its possible you are on a wild goose chase.

I would advice to do the manual polar alignment through the polar scope instead of the 3-star alignment. Then do 3-star and ignore what the mount thinks your errors are.

 

[carastro]

I would have thought Polar alignment was done BEFORE 3 star alignment. 

Carole

 

[michael8554]

PA is done first. This sets the RA axis to follow the apparent motion of the stars across the sky, and minimises Dec drift.

For visual use the polarscope PA should be good enough, but for imaging, the better you get PA, the longer the exposures can be before elongation of stars in the images occurs. 

If you're guiding, a PA error of 5arcmins is good enough.

Then Star Alignment. For any given date and time the mount's sky map knows where the alignment stars should be, and does GoTos to those positions.

Centring the chosen stars tweaks the mount's sky map into sync with reality.

Unlike the stars, the path of planets across the sky is complex and dynamic, so GoTos may not be perfect.

Michael

[M40]

My routine is more or less the same each time. Stick the telescope and stuff on the mount, balance it, set the home position, polar align then 2 star align. The closer you are with the home position and polar alignment, the star align is more or less there with the second star. Looking at your list of stuff, it's well within the capabilities of the mount. I have found with a heavier telescope and heavy bits and bobs added, it's close to the max and the mount does struggle a tad. So quick question, noting you mention "new to me" it suggests that your mount is not new, so, does your mount jump at all? are the clutches slipping?

[ONIKKINEN]

49 minutes ago, carastro said:

I would have thought Polar alignment was done BEFORE 3 star alignment. 

Carole

 

True, but you can use 3-star alignment as a polar alignment method since it will tell you your error after the third star is aligned. I think OP was trying to do that in this case.

You have to do that several times to get it anywhere near aligned, but its doable for situations where Polaris is not visible.

[imakebeer]

2 hours ago, michael8554 said:

Unlike the stars, the path of planets across the sky is complex and dynamic, so GoTos may not be perfect.

Michael

Good point. I didn't know that but obvious now you point it out. I'll try a star next time.

1 hour ago, M40 said:

So quick question, noting you mention "new to me" it suggests that your mount is not new, so, does your mount jump at all? are the clutches slipping?

I don't believe it's more than 2-3 years old and barely used from what the seller explained to me (a forum member so I can check). As much as I'm new to this I'm not completely daft with mechanical things and my gut feeling doesn't tell me there's anything untoward going on mechanically.

[newbie alert]

Since this has to do with your pointing inaccuracy it's necessary to point out it has nothing to do with the level of the mount and also nothing to do with your PA... From reading through you messed your star alignment up as you adjusted the bolts to do your PA.. always PA first and then star align...

You can level the mount but its not as important as when using a AZ mount

Pa with your preferred method but the polarscope method is a deemed a rough alignment for astrophotography and it needs collimating for it to have a level of accuracy

Then star align... If you can use a cross haired eyepiece to accurately place the star in the center or use the bullseye on your capture software if using a camera then it's far more accurate than placing the star in the center ( ish) of a ep..

Or just platesolve

 Also remember that the motion of stars ( sidereal) is different to the planets, not by much but its different 

[imakebeer]

21 minutes ago, newbie alert said:

From reading through you messed your star alignment up as you adjusted the bolts to do your PA.. always PA first and then star align...

I appreciate your suggestion but I'm struggling to buy this explanation...

If this is the case then how come (a) the polar alignment option in the handset doesn't appear until you've done a 2 or 3 star alignment, and (b) there are videos aplenty on YouTube of folks demonstrating this technique, including showing how it reduces the assignment error?

I'm also not sure how it differs from Sharpcap where you align based on stars and then adjust with the alt. & az. bolts 🤔

[newbie alert]

2 minutes ago, imakebeer said:

I appreciate your suggestion but I'm struggling to buy this explanation...

If this is the case then how come (a) the polar alignment option in the handset doesn't appear until you've done a 2 or 3 star alignment, and (b) there are videos aplenty on YouTube of folks

There's various ways to PA, some suit some people and others dont... but none will  have a accurate star alignment if you pa and move the Az and Alt bolts afterwards...You don't need to even switch the mount on to polar align

(B) plenty of things on  u tube that is fake/ false, don't mean it's correct... If you did it right and followed the proceedure as they show why have you got an error?? if you re star align or platesolve after( again ) it will rectify the error that you caused...

 

 demonstrating this technique, including showing how it reduces the assignment error?

I'm also not sure how it differs from Sharpcap where you align based on stars and then adjust with the alt. & az. bolts 🤔

Sharpcap uses stars that rotate around Polaris to pinpoint the ncp, ie Polaris takes slightly less than 24 hours ( ish)to do a  full revolution , if you try to align on a star in the south it will move across the sky according to our perspective alot faster as it's on a wider arc than polaris, even thou it takes the same time to do a full revolution, remember we are moving, revolving..

 

[wookie1965]

I have a EQ5 I level my mount and polar align before adding weights or scope then check it again after I have put them on. 

The first star is always a fair bit out what I do is defocus the star making it as big as possible easier to centre not having a cross hair eyepiece. 

The second and third stars will be closer and the third should be near on as it gets. 

As long as your targets are in the FOV I would not worry too much, there is a procedure you can do which is PEC training (periodic error correction) when the mount stops and the object is in the FOV press back then press on back again this time holding it down until the mount says centre object do that finishing with right and up (helps with backlash) you will find it more accurate. 

Hope this helps. 

Paul 

[woldsman]

This brings back plenty of memories of frustration with 3 star alignment. Assuming the polar alignment and all the data inputted (latitude, date, time) is right, these tips may help.

Tip 1: start with the Mount in the home position.

Tip 2: don’t be tempted to unlock the RA or DEC clutches at any point after polar alignment is done. Only use the handset to move the mount. Try and go in one direction eg left and then the other eg up to centre the star.

Tip 3: choose as the third & final star a star that is close to whatever target you plan to view. You are then in with a sporting chance of going to the target successfully.

 

Edited December 1, 2022 by woldsman

[woldsman]

17 minutes ago, wookie1965 said:

I have a EQ5 I level my mount and polar align before adding weights or scope then check it again after I have put them on. 

I’ve heard about this. My scope is quite light (71mm frac) so I feel ok about adding it & the counter weight before PA. With very heavy setups isn’t there a school of thought that the adjustment bolts can be strained. So unless you are on, say, grass  if the ground is stable your technique is safest. But for light setups, you might as well load up & just do PA once. Does this make sense!?

PS freezing fog where I am so reading the forums to avoid lamenting over the Mars opposition.

 

[Knighty2112]

What size EP did you use when you did your 3 star align? Always best to use a higher magnification initially to get the alignment more accurate, then you can drop it down after that with another EP if you want. Also, align the mount with the final way that the mount slews on to an object when slewing to an object, so if for example in its final movements it goes up, then to the right make sure your do your final 3 star alignment adjustments this way too to take out any gear backlash effects.

[carastro]

2 hours ago, newbie alert said:

Totally agree that you messed up your alignment by doing PA afterwards.  
 

Carole

Edited December 1, 2022 by carastro

[M40]

2 hours ago, imakebeer said:

I appreciate your suggestion but I'm struggling to buy this explanation...

If this is the case then how come (a) the polar alignment option in the handset doesn't appear until you've done a 2 or 3 star alignment, and (b) there are videos aplenty on YouTube of folks demonstrating this technique, including showing how it reduces the assignment error?

I'm also not sure how it differs from Sharpcap where you align based on stars and then adjust with the alt. & az. bolts 🤔

For your own piece of mind, check the alignment of the polar scope in the mount, this can be done at any time. Focus on an object, spin the mount head mechanically and the object should remain centered in the polar scope crosshairs. If it doesn't adjust it till it does, if it remains centered, you are good to go.

As has been said above, polar align before star align. Look at it this way, the home position and polar alignment mechanically sets the mount to its starting position. If you star align and then mechanically move the mount, the software will send the mount to the wrong position so you will need to start again.

If you have read that you adjust the bolts after star aligning, this is incorrect.

[wookie1965]

9 hours ago, woldsman said:

I’ve heard about this. My scope is quite light (71mm frac) so I feel ok about adding it & the counter weight before PA. With very heavy setups isn’t there a school of thought that the adjustment bolts can be strained. So unless you are on, say, grass  if the ground is stable your technique is safest. But for light setups, you might as well load up & just do PA once. Does this make sense!?

PS freezing fog where I am so reading the forums to avoid lamenting over the Mars opposition.

 

The bolts do bend I know because it wrecked my mount luckily a good friend on here re-engineered it for me, but I dont take any chances.

[carastro]

Quote

For your own piece of mind, check the alignment of the polar scope in the mount, this can be done at any time. Focus on an object, spin the mount head mechanically and the object should remain centered in the polar scope crosshairs. If it doesn't adjust it till it does, if it remains centered, you are good to go.

Yes, good advice.  There should be some small grubs screws on the polar scope itself so you can adjust it.  

Edited December 2, 2022 by carastro

[Owmuchonomy]

Your issue is that you are trying to do two somewhat unrelated processes as one.  PA is to align the RA axis of your mount.  Star alignment is to set up your GoTo function.  They are not related.

Are you imaging or observing?

If you are observing, PA does not have to be accurate. Set the equipment to the home position. Do a rough PA using the polarscope then leave it alone.  Next do your star alignment.  If you think your set up is suffering from cone error then do a 3 star alignment using the handset routine.  If you are not so concerned about cone error do the 2 star routine from the handset.  You will then be good to go.

If you are imaging, repeat the above but do a TWO star alignment using stars on the SAME side of the meridian that you wish to image.  Next, run the PA routine from the handset.  It will take about 2 or 3 iterations to produce accurate results.  Then, repeat the 2 star alignment if it has moved somewhat during the PA routine.

[StevieDvd]

What you did was almost right, and the comments about you ruining your alignment were correct.

If you read the manual for the PA process in the handset manual (yes some of us do read manuals) you do a 3 part process:

1. 2 or 3 star alignment (this logs corrections the mount needs to use, due to a poor PA). This helps get you targets in the view, helps the next process as well.
2. Do the PA adjustments using the alt/lat bolts.
3. Re-do a 2 or 3 star alignment.

The other mistakes often made are the date format, the time (DST or GMT) and/or location.

HTH

Steve

SynScan_HandControl_web191112v3_2_.pdf

 

[imakebeer]

I'm gonna preface this by saying if I come across a rude or ungrateful for asking for help and then not taking it, this really isn't the case. It's more that I tend to learn things by arguing when things don't make sense (I still remember doing this with my A-Level physics teacher, not that I ever won an argument!). All of your comments are genuinely very helpful because it's making me question stuff and figure out the answer and get it straight in my own head. Sincerely, thank you all for your help 😁👍

I'm still not buying the argument that I messed things up by doing the Synscan handset polar alignment after the 3-star alignment. If this was the case how come Polaris was outside the polar scope FOV at the start and inside the FOV afterwards, surely that's an improvement? @StevieDvd has beaten me to it by posting a link to the Synscan manual, which I was already looking at earlier - the manual is clear that the polar alignment routine is only available after you do a 2- or 3-star alignment so why on earth would SW hide it initially if it wasn't meant to work this way round?

(but I do agree if you did a traditional manual polar alignment through the polar scope using the HA of Polaris then no, you don't want to mess with the alt. & az. bolts afterwards)

In this regard, the YouTube videos are just repeating what the manual says. However, what the manual goes on to say (and the YouTubers don't make clear, but @StevieDvd notes above) is:

"Go back to the “Alignment” menu on the SynScan hand control and execute another 2-Star or 3-Star alignment... Repeat [ ] until the error is small enough and acceptable. Generally, users can get up to 1 arc-minute polar alignment accuracy after repeating this polar alignment process 2 or 3 times."

So actually I was (by luck rather than judgement!) on the right track when I started to do another 3-star but fog stopped play. My hunch is that had I done it a couple more times then Polaris should have ended up where it wants to be in the Polarscope reticle.

With regard to mechanical backlash the manual also notes in a couple of places that:

"When centering an alignment star in the eyepiece, the operation should always end by using the UP and RIGHT direction keys to move the axes."

@Knighty2112 pointed this out above too - I didn't know to do this, but will do so in future (oh and the manual also says what you said about using a higher magnification eyepiece for alignment or one with crosshairs 👍)

The point about making sure the polar scope reticule is correctly aligned with the RA axis - yeah, I'd seen some videos about this. I haven't checked but it's on my to-do list 👍

My gut feeling is primarily I'm really not helping myself by starting with polar alignment so far out of whack - I can see Polaris clearly from my front drive or back garden (well, I could if the flippin' clouds ever cleared!😖) so better to start off as close as possible.

@Owmuchonomy (great username BTW 😂) to answer your question right now I'm neither observing nor photographing 'cos I'm still trying to get the hang of this new mount! 🤣 But ultimately the plan is a bit of both - and sure, I understand that for observing you need not be quite so precise but for AP you need to be spot on. I've already had some experience doing planetary AP with our EQ1 + Capricorn frac, including having to tweak both the RA and Dec. because it's hard to get everything spot on with this mount!

With the HEQ5, besides a lot more heavy lifting 💪🤣 you've got tons more options to help you get it spot on. My gut feeling is once it has clicked then it's really not that hard to get very close alignment pretty quickly regardless of visual or AP which is why I'm trying to get it straight in my head now. I took some time to get my head around setting up the EQ1 which was time well spent so I'm confident the effort now with the HEQ5 will pay back soon.

Again, thank you everyone for your help and suggestions 😁👍🔭

[happy-kat]

I apologise in advance if I've muddied and not helped, sorry

If the EQ mount is manual then being polar aligned allows using the ra slow mo handle to track the star across the sky. A mount with motors on both axis still has a core movement of the head on it's axis, if the setup is not aligned on Polaris (or specifically the North Celestial Pole for exact accuracy) then the core movement of the mount head won't follow and track a star across the sky with the telescope following the right amount of rotation (an issue if imaging). Altaz follow a star by tiny left right up down keeping the object in the field of view but the target is rotating and smearing if imaging.

Edit: corrected for NCP accuracy as pointed out below

Edited December 2, 2022 by happy-kat

[newbie alert]

1 hour ago, happy-kat said:

I apologise in advance if I've muddied and not helped, sorry

If the EQ mount is manual then being polar aligned allows using the ra slow mo handle to track the star across the sky. A mount with motors on both axis still has a core movement of the head on it's axis, if the setup it not aligned on Polaris then the core movement of the mount head won't follow and track a star across the sky with the telescope following the right amount of rotation (an issue if imaging). Altaz follow a star by tiny left right up down keeping the object in the field of view but the target is rotating and smearing if imaging.

You don't align on Polaris, you align on the north celestrial pole, which is near but 40 odd arc mins away..

Sorry to be precise but giving a newbie false info , it's confusing enough... I was told this when I first started, and set me back a fair bit..  so sort of grates when I hear it repeated