Polaris moves in polar scope depending on

[TiffsAndAstro]

10 hours ago, StevieDvd said:

Your mel/maz settings still be the same is worrying.  It is the adjustment that the mount expects to correct your PA when doing a goto.  

The SW PA/Align process for users without a polarscope is documented in the handset manual and involves doing a series of PA and Aligns to reduce the Mel/Maz 

Even the slightest adjustment  of the Alt/Az would change those numbers. But if the app is the same as the handset method the values may only change after last 2 or 3 star alignment

i'd love to see a synscan app manual somewhere  

[TiffsAndAstro]

9 hours ago, malc-c said:

I did say it was a simplified set up, and I've never seen an Gti scope to find out that skywatcher changed the traditional design of having a pin on the mount onto which the azimuth adjustment screws press against.

Given that this thread is now some three pages long and we seem to have covered basic polar alignment which has only led to confusion, I agree with the poster above that it would be worth making further enquiries at your local club or society.  We have members in our society who are often willing to assist on a private one to one basis where its easier to teach people how to set a scope up by being there than over the phone or posts on a forum.  As a society we also run telescope workshops where members / or prospective members can bring their scopes along and get answers to questions they may have.

With regards to the requirement of rotating the mount to place polaris in the correct position, hopefully the drawing below might help.

 

For argument and to make it simple, lets say that Polaris is at the 9 O'clock position in its 24 hour rotation around the NCP.  Placing Polaris on the ring at the 9 O'clock would correctly place the NCP to the right.   If you didn't know the position of Polaris and simply placed it anywhere on that ring, such as at the 3 O'clock position the this would place the NCP (and the RA axis of the mount) way off to the left.

I also read through the online manual and the mount set up, particularly the PA is very poorly defined.  Goes off at a tangent to describe a utility to show the Polaris Hour, but then no real detail on what to do with it.

One other thing, I think the OP needs to take on board that PA is critical if you are doing unguided exposures.  The earth is spinning really fast and any error will result in anything form egg shaped stars to trails.  I can remember a thread where people were competing for the longest un-guided exposure before misshapen  stars or trails were seen when using an HEQ5 mount.  From memory it was around 5 minutes but the mount had been hypertuned and PA was done via plate solving, but that was the extreme required.   Given the large tolerances and variables such as the way Polaris appears to move within the polar scope 20 - 30 seconds exposures will probably show trailing etc when un-guided.

 

 

im going to jinx myself, but i did a test earlier at 5mins and it looked good. i think stopping down to (i think) f4.5 helped make the stars a little more rounded, but just in case ive dropped it to 3mins and tests look good.

all i've done toinight is:

point polar scope/mount towards polaris

centered polaris in cross hairs of the polar scope.

move alt bolt so polaris is at the top on the center of the three rings.

moved dec so that zero/12oclock is where polaris is in the polar scope and lock dec clutch.

used alt/az bolts to position polaris in the polar scope at the correct clock position as shown in the synscan app tighten az bolts and the big bolts.

2 star alignment in the app

135mm 600d f4.5 iso400 (lots light pollution) and 182 or 183 sec subs cos my intervalometer combined with 2 sec mirror lock up has some issues i think.

once orion drops too low i might have another go with polar alignment via app and the alt/az bolts.

ty all for your efforts in helping me with this. 

 

[TiffsAndAstro]

5 hours ago, StevieDvd said:

Okay it appears you have grasped the PA process both using the polarscope and the app.  And as you can get the mel/maz values can see how far off you are from a good PA, at best these would both be zero. But probably 1 arc-minute would be the best you could expect to get (according to SW) 

I had the SW GTi briefly before I upgraded to a ZWO AM5 and never used the polarscope. I set the Alt based on my location and pointed North using my iPhone then PA'd via the app or a connected ASIAir, that was for visual I did not image with the SW Gti.

So based on your equipment and software:

As I still have the Syncan app and can set it to simulate mode I can see the stages you would go through as an iterative process (align, PA, align & check)

• Check your date/time & location are correct in the app
• Start PA process until mel/maz value is as low as possible
• Do a 2 or 3 star alignment
  • End with an Up/Right click
  •  Check the mel/maz error
• Do the PA using the Alt/Az bolts as needed.
• Redo a 2 or 3 star alignment
  • End with an Up/Right click
  •  Check the mel/maz error
• Repeat  as required

When you adjust the Azimuth bolts, loosen one side as you tighten the other, but make sure they are not left loose. The end on Up/Right move for aligning is per SW notes to cater for backlash.

Home position - if your PA is good a poor home position may make the first go-to look bad.  I would loosen the clutches and centre the object - not use the cursor keys or alt/az bolts.  I'd then do a go to 'home' and retry the first go to - the mount will set a home position, better than you can, and later each subsequent go to should be accurate as well.

 

NB You can add a custom target in the app for 'home' to be able to do a go to home

     

 

Hope this helps rather than confuse. I think I have covered the essentials - someone may spot anything I've missed.

Steve

 

 

i want to read your post more thoroughly, but the app won't let me attempt a PA until i've done a 2 star alignment. i think it gets mel maz values after a 2 or 3 star alignment.

tbh even with what has turned out to be bad polar alignment at times the goto has been good to amazing. im not using big focal lengths though. 

ok your post really helps ty - just a bit confused about doing a pa in app before i do a 2 or 3 star alignment. 

also about home position. let me reread and have a think and see. ty so much for all of this. 

Edited March 6 by TiffsAndAstro

[bosun21]

40 minutes ago, TiffsAndAstro said:

well polaris moves when i use them

Yes it's just that your mount has a different azimuth adjustment mechanism than most other mounts.

[StevieDvd]

13 hours ago, TiffsAndAstro said:

i'd love to see a synscan app manual somewhere  

Look here then 😀 though it's not illustrated.

synscan_app_manual_en_20230525.pdf

[malc-c]

13 hours ago, TiffsAndAstro said:

im going to jinx myself, but i did a test earlier at 5mins and it looked good. i think stopping down to (i think) f4.5 helped make the stars a little more rounded, but just in case ive dropped it to 3mins and tests look good.

all i've done toinight is:

point polar scope/mount towards polaris - Yes, this is good

centered polaris in cross hairs of the polar scope. 

move alt bolt so polaris is at the top on the center of the three rings. very good...

moved dec so that zero/12oclock is where polaris is in the polar scope and lock dec clutch.

used alt/az bolts to position polaris in the polar scope at the correct clock position as shown in the synscan app tighten az bolts and the big bolts.  By Jove I think he's got it !

2 star alignment in the app

 

That's it.... no need to do anything else

[TiffsAndAstro]

4 hours ago, StevieDvd said:

Look here then 😀 though it's not illustrated.

synscan_app_manual_en_20230525.pdf 252.9 kB · 0 downloads

Ty so much.

Though I'm beginning to think synscan app has hints of being born of box ticking rather than enthusiasm to make a great tool.

I might be being a tad harsh  though.

Tempted to try an asiair mini.

[TiffsAndAstro]

16 hours ago, bosun21 said:

Yes it's just that your mount has a different azimuth adjustment mechanism than most other mounts.

From what I can make out, that's in the very base of the mount which is then screws into more conventional photographic tripod.

The gti was apealing because it wasn't much more than a tracker but offered features of grown up mounts and portability.

I was getting a bit lost watching videos of people using ra (maybe dec?) Clocks on their mounts but not finding them on mine. 

I'm hoping the lack of such things wouldn't hold me back in the future. I'm not planning of putting anything huge and expensive on it but tinkering with guiding appeals.

[TiffsAndAstro]

Ty all again for all your efforts. I'm not there yet, but I do feel I at last have the ball park in sight. 

I'm sure I wont need any assistance again in the future

 

[Elp]

Asiair (or equivalent, try NINA on a laptop it's free) makes all this so much easier. Once I went air, I stopped faffing around and got on with imaging. BUT, you still have to understand the principles, and you'll have to know how to fault find at times though that applies with or without computer controllers.

[TiffsAndAstro]

My 182/3 sec subs stars looked egg shape, but any trails were small enough to be within those egg shapes. I think.

Detail in m42 seemed ok, could see the running man, but my best version so far is a bit blue so still working on it.

I will post an example sub and blue m42 when I get home. 

[TiffsAndAstro]

7 minutes ago, Elp said:

Asiair (or equivalent, try NINA on a laptop it's free) makes all this so much easier. Once I went air, I stopped faffing around and got on with imaging. BUT, you still have to understand the principles, and you'll have to know how to fault find at times though that applies with or without computer controllers.

Yeah I agree, I wanted some time doing it the traditional way so I'd have more context when doing on a computer.

I'm going to try nina with my 600d from videos it seems I should be able to try out polar alignment and plate solving.

Attaching even an asiair mini to a DSLR on a maybe 6 inch dovetail bar doesn't seem trivial either. Let alone a guide scope.

[Elp]

What focal length?

[TiffsAndAstro]

Just now, Elp said:

What focal length?

You name them, I have them all

135mm at the moment seems a nice balance for me as a beginner.

My plan was to buy a few vintage primes to get a feel for focal lengths before maybe buying a proper lens or scope.

600d is 1.6 crop but my lens native fl are 50, 135, 200 and 500.

None of them seem good, so a samyang 135 appeals at the moment.

The 500 is a mirror lens and a bit crap. If my skills improve I might be able to do better with it.

 

[Elp]

As you're not autoguiding I'd suggest you trial the 50mm more if you've got the angle of sky to take in the FOV. Once you go telephoto say 100mm+ you really need to start autoguiding unless you have a super tracking mount (say like an Astrotrac or Fornax Lightrack). I would never trust my azgtis in built tracking to image at 100mm even with the best polar alignment in the world. You also have to make sure your RA and DEC imaging payload balance is pretty much spot on or else that can also lead to trailing stars. Less focal length is a lot more forgiving.

[TiffsAndAstro]

9 minutes ago, Elp said:

As you're not autoguiding I'd suggest you trial the 50mm more if you've got the angle of sky to take in the FOV. Once you go telephoto say 100mm+ you really need to start autoguiding unless you have a super tracking mount (say like an Astrotrac or Fornax Lightrack). I would never trust my azgtis in built tracking to image at 100mm even with the best polar alignment in the world. You also have to make sure your RA and DEC imaging payload balance is pretty much spot on or else that can also lead to trailing stars. Less focal length is a lot more forgiving.

50mm f1.7 on a tripod let me fit in orion from betelguese to rigel, but m42 and flame were small. Also wide field of view limited my time due to houses and trees. I am tempted to give it another go now I have a tracker but my lens heater is a bit big and finding stuff at 135mm is no problem. 

Maybe it might be a good idea to try nina on the 50mm first though.

Also balancing with such a light load is...maybe a little vague. Even with both clutches disengaged, there is a little resistance to movement, unless really front or back heavy.

Edited March 7 by TiffsAndAstro

[Elp]

I get the same with my azgti, the resistance I think actually helps. I wouldn't get away with it though with my ioptrons, they're fractional mm reactive to counterweight positions for balancing.

[TiffsAndAstro]

stars have more trails than i thought

IMG_8881.CR2

[Elp]

They're not too bad, the top one is out of focus so you'll see it worse than it is.

[TiffsAndAstro]

21 hours ago, Elp said:

They're not too bad, the top one is out of focus so you'll see it worse than it is.

They're both from same data. Cack handed crops plus i might have removed some subs with slight clouds for one.

I struggle with curves on star mask before combing back with starless.

i seem to lose the running man when i put them back together in siril, but its good practice. The starless version is quite nice (relatively)

Edited March 8 by TiffsAndAstro

[TiffsAndAstro]

Also I've noticed that before polar alignment I set my lat bolts so the mount dial shows 52.3 (ish), but if I check it  after polar alignment it's about 1.5(ish) degrees higher.

 

Does this suggest tripod issues  or maybe the mount dial is only roughly accurate? Or something else?

I did notice the dial pointer isnt quite perpendicular to the scale itself.

[Cornelius Varley]

12 minutes ago, TiffsAndAstro said:

Also I've noticed that before polar alignment I set my lat bolts so the mount dial shows 52.3 (ish), but if I check it  after polar alignment it's about 1.5(ish) degrees higher.

 

Does this suggest tripod issues  or maybe the mount dial is only roughly accurate? Or something else?

I did notice the dial pointer isnt quite perpendicular to the scale itself.

The latitude scale is only a rough guide.

[TiffsAndAstro]

1 hour ago, Cornelius Varley said:

The latitude scale is only a rough guide.

Ty for this

[malc-c]

On 08/03/2024 at 15:46, TiffsAndAstro said:

Also I've noticed that before polar alignment I set my lat bolts so the mount dial shows 52.3 (ish), but if I check it  after polar alignment it's about 1.5(ish) degrees higher.

 

Does this suggest tripod issues  or maybe the mount dial is only roughly accurate? Or something else?

I did notice the dial pointer isnt quite perpendicular to the scale itself.

 

You have to understand that these are mass produced commercial telescopes and as such lack precision.  The scales and indicators are to get you close within the limits of the design (thickness of the lines on the dial, or indicator).

If you want absolute precise PA then plate solving is the only way to eliminate any errors and get the mount aligned to the best of its abilities.  Again, it's horses for courses, you will get more accuracy with more expensive mounts as they are produced to a higher degree of precision and tighter tolerances.

 

Looking at your nebula image, its a bit difficult to see given the 1200 x 800 resolution, but it seems the slight "unroundness" seems to be in one direction, which could quite simply be the fact that Alignment is good, but the tracking is struggling.  This could be a multitude of reasons, from the scope not being balanced correctly, or balanced to well without any bias to remove backlash in the gearing. We've certainly seen far worse first attempts so don't be too downhearted.

One thing to remember is you don't need to expose for long periods to get data.  Sometimes it's easier to take 100 x 10, 15 or 20 second exposures and then stack them and let the post processing do the work to bring out the details, than to try and take 50 x 1 or 2 minute exposures that end up spoilt by tracking or alignment issues.  

 

[TiffsAndAstro]

4 hours ago, malc-c said:

 

You have to understand that these are mass produced commercial telescopes and as such lack precision.  The scales and indicators are to get you close within the limits of the design (thickness of the lines on the dial, or indicator).

If you want absolute precise PA then plate solving is the only way to eliminate any errors and get the mount aligned to the best of its abilities.  Again, it's horses for courses, you will get more accuracy with more expensive mounts as they are produced to a higher degree of precision and tighter tolerances.

 

Looking at your nebula image, its a bit difficult to see given the 1200 x 800 resolution, but it seems the slight "unroundness" seems to be in one direction, which could quite simply be the fact that Alignment is good, but the tracking is struggling.  This could be a multitude of reasons, from the scope not being balanced correctly, or balanced to well without any bias to remove backlash in the gearing. We've certainly seen far worse first attempts so don't be too downhearted.

One thing to remember is you don't need to expose for long periods to get data.  Sometimes it's easier to take 100 x 10, 15 or 20 second exposures and then stack them and let the post processing do the work to bring out the details, than to try and take 50 x 1 or 2 minute exposures that end up spoilt by tracking or alignment issues.  

 

my plan atm is to give nina a try see how polar alignment goes with that. just trying to update my old macbook then plop bootcamp windows on it and see if it works

also, i think my stars look so bad they hide some trailing. 

i've attached (i think) a higher res version. the stars are annoying the nebula is not too bad. I think im going to have to get a nicer lens.