Polaris moves in polar scope depending on

[malc-c]

It was as an example of why the mount would end up with the RA axis rotated away form the home position.  Nothing else.   The fact EQMOD rotates the mount precisely to the hour position helps if you use that software, but it can still be done manually 

If Polaris was bang on the NCP then it would be simple to place it under the cross-hairs of the polar scope.  But as it orbits the NCP placing it inside the "bubble" or the ring (depending on the age of the mount) at the correct hour the mount needs to reflect that so you get the RA axis inline with the Earths axis.  BUT this is only really important if you are intending to image with the set up.  Visually you could just place Polaris under the central cross-hairs and it would be good enough.

The only other suggestion if you are stull hung up on PA is to use the search function and read the 100's of previous posts on the subject, or search YouTube and watch any of the 1000's of videos on the subject. 

If you are still looking for a precise alignment then look at shelling out for a Polemaster camera and use  plate solving such as the plugin featured in Sharpcap (Other plate solving applications are available)  

[900SL]

You don't need to have the polarscope with 12 o clock pointing straight up when polar aligning. What is important is having Polaris in the correct position on the dial. So if your app shows 3 o clock for your location, time and date, adjust alt az bolts to get polaris approx plus 90 degrees clockwise from vertical.

It is also important to know that polarscopes invert the image (upside down, left to right) so make sure your app is showing an inverted view.

After polar aligning, DO NOT touch the alt az bolts again. Three star alignment is not the same as Polar alignment.  Three star alignment tells the mount where it is pointing, which might not be the same as pointing to polaris (NCP). After Three star alignment the mount uses both axes motors to track an object, and may have rotation of field in long exposures. Polar alignment means that only the RA axis needs to rotate, with negligible rotation

 

[TiffsAndAstro]

So last night I polar aligned through scope.

Did 2 star alignment (mount found both within pixels of center of screen)

Did a pa via synscan app  could center star as directed using alt and az bolts.

Did another pa near my target.

Got curving trailing stars on 5 minute sub.

So either my pa is still [removed word], my tripod is [removed word] in a 5 min cycling type of way  my mount is broken or....? IMG_8307.CR2

[TiffsAndAstro]

Orion is still my priority but I'm running out of time.

If there's holes in the cloud this evening I'll repeat my pa set up but revert back to 50mm pentax f1.7 and see if I can at least get round stars and get what I can of orion.

[TiffsAndAstro]

On 01/03/2024 at 07:16, 900SL said:

You don't need to have the polarscope with 12 o clock pointing straight up when polar aligning. What is important is having Polaris in the correct position on the dial. So if your app shows 3 o clock for your location, time and date, adjust alt az bolts to get polaris approx plus 90 degrees clockwise from vertical.

It is also important to know that polarscopes invert the image (upside down, left to right) so make sure your app is showing an inverted view.

After polar aligning, DO NOT touch the alt az bolts again. Three star alignment is not the same as Polar alignment.  Three star alignment tells the mount where it is pointing, which might not be the same as pointing to polaris (NCP). After Three star alignment the mount uses both axes motors to track an object, and may have rotation of field in long exposures. Polar alignment means that only the RA axis needs to rotate, with negligible rotation

 

Ty for this. I only touch the alt az bolts for polar alignment, I've had it explained star alignment is almost unrelated.

 

So the grinning curving star streaks I saw would be fixed by guiding?

 

[900SL]

48 minutes ago, TiffsAndAstro said:

Ty for this. I only touch the alt az bolts for polar alignment, I've had it explained star alignment is almost unrelated.

 

So the grinning curving star streaks I saw would be fixed by guiding?

 

Possibly. Star trails come from two sources, (1) less than perfect polar alignment (drift) and (2) periodic error or less than perfect tracking (EDIT: (3) Wind or movement of tripod, mount etc)

If you want to do long exposures and have pin point stars you need to be accurately polar aligned and guiding, unless you have a $10K mount.

Most mounts vary in RA tracking due to manufacturing tolerances (the axis following the star movement in the sky E - W) so stars oscillate back and forth over time, and drift N-S due to errors in Polar alignment, or something like that.. it's been a while since I dove into the reasons

Guiding deals with most of that, provided you are not too far off on Polar alignment.

Ideal set up for beginner is an ASI Air for polar alignment, platesolving, imaging, and guiding. It's a magic little box for the beginner. And a guidescope and guide camera.

It aint a cheap hobby if you want an easy life and good results..

Edited March 4 by 900SL

[StevieDvd]

2 hours ago, TiffsAndAstro said:

So last night I polar aligned through scope.

Did 2 star alignment (mount found both within pixels of center of screen)

Did a pa via synscan app  could center star as directed using alt and az bolts.

Did another pa near my target.

Got curving trailing stars on 5 minute sub.

So either my pa is still [removed word], my tripod is [removed word] in a 5 min cycling type of way  my mount is broken or....? IMG_8307.CR2

Okay I think I see your problem.

You are still doing PA and star alignments in the wrong order.  Get the best PA you can first and then let the mounts note your inaccuracies and it will then adjust for them automatically. If you redo the PA and don't redo the star alignment the mount will be doing the wrong adjustments. So even if your second PA dos a better job you should let the mount redo the star alignment process to note that the adjustments needed are different.

 

[TiffsAndAstro]

8 minutes ago, StevieDvd said:

Okay I think I see your problem.

You are still doing PA and star alignments in the wrong order.  Get the best PA you can first and then let the mounts note your inaccuracies and it will then adjust for them automatically. If you redo the PA and don't redo the star alignment the mount will be doing the wrong adjustments. So even if your second PA dos a better job you should let the mount redo the star alignment process to note that the adjustments needed are different.

 

i saw a post elsewhere about the hand controller and PA with another sw mount. it looks to me that the synscan app is trying to replicate the features of the hand controller. if so, repeated PA on different stars is supposed to improve on the PA accuracy. 

i will give what you say a go next chance i get.

PA through scope.

2 star alignment in app

PA in app (but using alt az bolts as needed)

2 star alignment in app and i'm good to go?

 

one other thing - there are what looks like two larger alt locking bolts on the mount. should these be loose during the process and then righted up afterwards, or ? the user guide literally doesn't seem to mention what they even are lol.

Edited March 4 by TiffsAndAstro

[TiffsAndAstro]

1 hour ago, 900SL said:

Possibly. Star trails come from two sources, (1) less than perfect polar alignment (drift) and (2) periodic error or less than perfect tracking (EDIT: (3) Wind or movement of tripod, mount etc)

If you want to do long exposures and have pin point stars you need to be accurately polar aligned and guiding, unless you have a $10K mount.

Most mounts vary in RA tracking due to manufacturing tolerances (the axis following the star movement in the sky E - W) so stars oscillate back and forth over time, and drift N-S due to errors in Polar alignment, or something like that.. it's been a while since I dove into the reasons

Guiding deals with most of that, provided you are not too far off on Polar alignment.

Ideal set up for beginner is an ASI Air for polar alignment, platesolving, imaging, and guiding. It's a magic little box for the beginner. And a guidescope and guide camera.

It aint a cheap hobby if you want an easy life and good results..

yeah the asi air looks like a very useful thing.

i'd really like to improve my polar alignment skills manually,  but might have to just get one.

[malc-c]

19 hours ago, TiffsAndAstro said:

So last night I polar aligned through scope.   Excellent 

Did 2 star alignment (mount found both within pixels of center of screen) Fantastic

Did a pa via synscan app  could center star as directed using alt and az bolts.  NO !!!! you just undid the first step

Did another pa near my target.  Why you doing THREE polar alignments - 

Got curving trailing stars on 5 minute sub. No wonder - your subsequent PAs  have screwed up the initial alignment with the polarscope

So either my pa is still [removed word], my tripod is [removed word] in a 5 min cycling type of way  my mount is broken or....? IMG_8307.CR2

It's USER ERROR

Why oh why don't you read what people have already told you... Once you have polar aligned using the polar scope DONT DO ANY OTHER POLAR ALIGNMENT THROUGH THE HANDSET !!   The fact you stated that the two stars used in the normal set up alignment were pixel perfect in the centre of the field of view without making any adjustments suggest you had done a very good job of polar aligning using the polar scope.  You should have left it at that 

Apologies for the rant... but you should really read what people are posting and follow their

17 hours ago, TiffsAndAstro said:

i saw a post elsewhere about the hand controller and PA with another sw mount. it looks to me that the synscan app is trying to replicate the features of the hand controller. if so, repeated PA on different stars is supposed to improve on the PA accuracy. 

i will give what you say a go next chance i get.

PA through scope. 

2 star alignment in app

PA in app (but using alt az bolts as needed)

2 star alignment in app and i'm good to go?

 

 

[malc-c]

Basic Polar Alignment of an EQ mount

• Place the tripod on the ground with one leg (often indicated with an N) facing North.  Ideally the tripod should be level.  A normal magnetic compass can help if you are not sure which direction North is
• Place the mount on the tripod and secure it by finger tightening the bolt.  The two Azimuth adjustment bolts should be open enough to fit the spike on the tripod between them
• Set the angle of the mount to match the latitude where you are observing from
• Read the manual that came with the scope and set up the alignment of the polar scope as suggested - this can be done in the daylight and use a landmark that is some distance away.  It can be tweaked further at night but centring Polaris in both the finder scope, main scope and then the polar scope.  
• Once the polar scope has been set up place the mount in the default home position (google that if not sure)
• Use the AZ and latitude bolts on the mount to centre Polaris on the cross hairs of the polar scope
• Look up the position of Polaris to get its orbital position 
• Use the latitude adjustment bolt to move Polaris to either the 12 or 6 O'clock position
• Slacken of the RA lock and rotate the mount until the bubble or markings on the polar scope is in the same "hour" of Polaris is in its rotation around the NCP and then lock off the RA axix
• Use the Az bolts and Latitude bolts to place Polaris on the ring and in the bubble / markings  (as shown in that video I linked to)
• Once in position tighten the securing bolt and check that Polaris is still on its mark
• Release the RA lock and place the mount back into the default home position.
• Power on the mount and run through a 2 or 3 start alignment.
• If any of the target stars are slightly off the centre of the eyepiece then make the small adjustments USING THE DIRECTIONAL BUTTONS ON THE HANDSET  - Do NOT use the AZ/Lattitude bolts
• Once the alignment routine is complete place the mount back into the home position and then select your target.

This is a very simplified routine... but the main area where you are going wrong is that you are performing multiple polar alignments when they are not needed - It's a one off procedure done before any observing session

[TiffsAndAstro]

3 hours ago, malc-c said:

Basic Polar Alignment of an EQ mount

• Place the tripod on the ground with one leg (often indicated with an N) facing North.  Ideally the tripod should be level.  A normal magnetic compass can help if you are not sure which direction North is
• Place the mount on the tripod and secure it by finger tightening the bolt.  The two Azimuth adjustment bolts should be open enough to fit the spike on the tripod between them
• Set the angle of the mount to match the latitude where you are observing from
• Read the manual that came with the scope and set up the alignment of the polar scope as suggested - this can be done in the daylight and use a landmark that is some distance away.  It can be tweaked further at night but centring Polaris in both the finder scope, main scope and then the polar scope.  
• Once the polar scope has been set up place the mount in the default home position (google that if not sure)
• Use the AZ and latitude bolts on the mount to centre Polaris on the cross hairs of the polar scope
• Look up the position of Polaris to get its orbital position 
• Use the latitude adjustment bolt to move Polaris to either the 12 or 6 O'clock position
• Slacken of the RA lock and rotate the mount until the bubble or markings on the polar scope is in the same "hour" of Polaris is in its rotation around the NCP and then lock off the RA axix
• Use the Az bolts and Latitude bolts to place Polaris on the ring and in the bubble / markings  (as shown in that video I linked to)
• Once in position tighten the securing bolt and check that Polaris is still on its mark
• Release the RA lock and place the mount back into the default home position.
• Power on the mount and run through a 2 or 3 start alignment.
• If any of the target stars are slightly off the centre of the eyepiece then make the small adjustments USING THE DIRECTIONAL BUTTONS ON THE HANDSET  - Do NOT use the AZ/Lattitude bolts
• Once the alignment routine is complete place the mount back into the home position and then select your target.

This is a very simplified routine... but the main area where you are going wrong is that you are performing multiple polar alignments when they are not needed - It's a one off procedure done before any observing session

ty so much for this malcom, but, like the video you reference its confusing me

few questions:

1 - i screw the mount onto the 3/8 inch thread on the tripod. "The two Azimuth adjustment bolts should be open enough to fit the spike on the tripod between them"  - my tripod doesnt have a spike.

2 - the manual contains nothing about setting up the polar scope. i have watched videos on general alignment but don't want to try to use that on my mount. as a test, if i center polaris in the cross hairs and rotate ra, polaris seems to stay centered. 

3 home position - watching a video now from AstroFarsography. pretty sure i've never done this part - will find a spirit level for tonight after i watch the rest of the video.

4 "Slacken of the RA lock and rotate the mount until the bubble or markings on the polar scope is in the same "hour" of Polaris is in its rotation around the NCP and then lock off the RA axix" i think is the main bit of my confusion. the bubble that appeared on the video you linked does not appear on my polar scope. At this point as polaris should be on the middle ring at 12 oclock, i rotate the ra until polaris is in the postion shown by synscan app? bit lost here with the next part, sorry "Use the Az bolts and Latitude bolts to place Polaris on the ring and in the bubble / markings  (as shown in that video I linked to)" as if i rotate ra so polaris is in the correct position i wouldn't need to adjust alt/az bolts?

also a ra setting circle mentioned in the home position video i found doesn't seem to exist on my sw gti. also there seems no dec setting circle as in the video too. ive tried googling ones for my sw gti mount but very few about and none in detail

 5 "This is a very simplified routine... but the main area where you are going wrong is that you are performing multiple polar alignments when they are not needed - It's a one off procedure done before any observing session" i was expecting a polar alignnment done via the app/alt/az bolts would refine my polar alignment further.

Edited March 5 by TiffsAndAstro

[AstroMuni]

@TiffsAndAstro  The advice above makes perfect sense to me, but as its causing some confusion in your mind lets  keep it simple & try this again from scratch....

- To align your polarscope reticle try this https://www.myastroscience.com/polarscopecalibration

- Do NOT use your handcontroller for these steps

  - Position your mount so that Polaris is visible in your polarscope

  - Rotate the axis until the clockface is right side up (i.e 12 or 0 is up and 6 is down). Personally I am not fussed about the numbers themselves as long as it resembles a clock (eg. 3 maybe in 6 o'clock position)

  - Use the al-az knobs, latitude bolt until polaris is in the right position in the clock face. You can get the location from any polar alignment app on your phone

- You can now start using the hand controller to do star alignment etc.

DO NOT move your mount or adjust any knobs after doing star alignment!

Hope this makes sense 🙂 

Edited March 5 by AstroMuni

[TiffsAndAstro]

4 hours ago, malc-c said:

Why oh why don't you read what people have already told you... Once you have polar aligned using the polar scope DONT DO ANY OTHER POLAR ALIGNMENT THROUGH THE HANDSET !!   The fact you stated that the two stars used in the normal set up alignment were pixel perfect in the centre of the field of view without making any adjustments suggest you had done a very good job of polar aligning using the polar scope.  You should have left it at that 

Apologies for the rant... but you should really read what people are posting and follow their

 

I do read them and massively appreciate their time and effort. however theres seems to be conflicting ideas at least to a noob like me  and stuff that doesnt even seem to apply to my mount.

 

For example I seem to be being told to line up Polaris in the scope via slt/az bolts and ra now and both can't be the correct approach to a noob like me.

 

Bare in mind a little knowledge can be a dangerous thing.

For me  I mean.

Edited March 5 by TiffsAndAstro

[TiffsAndAstro]

15 minutes ago, AstroMuni said:

@TiffsAndAstro  The advice above makes perfect sense to me, but as its causing some confusion in your mind lets  keep it simple & try this again from scratch....

- To align your polarscope reticle try this https://www.myastroscience.com/polarscopecalibration

- Do not use your handcontroller for these steps

- Position your mount so that Polaris is visible in your polarscope

- Rotate the axis until the clockface is right side up (i.e 12 or 0 is up and 6 is down). Personally I am not fussed about the numbers themselves as long as it resembles a clock (eg. 3 maybe in 6 o'clock position)

- Use the al-az knobs, latitude bolt until polaris is in the right position in the clock face. You can get the location from any polar alignment app on your phone

- You can now start using the hand controller to do star alignment etc.

- DO NOT move your mount or adjust any knobs after doing star alignment!

Hope this makes sense 🙂 

It does ty astromuni.

It's also what I think I was managing to do. 

I was doing further polar alignments in conjunction with the alt/az bolts and synscap app.

I posted my mel maz and now vaguely understand what they're for, but not the meaning of the values as I have no context.

If clear tonight will follow your steps exactly and do 1 3 and 5 min subs to test.

Edited March 5 by TiffsAndAstro

[AstroMuni]

2 minutes ago, TiffsAndAstro said:

I posted my mel maz

Sorry, whats this??

[TiffsAndAstro]

4 minutes ago, AstroMuni said:

Sorry, whats this??

I took a photo of my mel maz things other night see if anyone could share any light on the values then googled the terms. They seem to be a measure of pa accuracy, maybe? Synscap app wont let me doing an in app polar alignment until it has mel maz values from a 2 or 3star alignment.

[TiffsAndAstro]

 01:00

so after doing a second pa i looked in information:

id=2'28.5' ch=00.0' np=00.0'

mel=00.1' maz=06.4 tilt=03,8'

 

Sorry it was un a different post

 

Apologies if my replies are clunky. I'm on a phone atm and I'm old

also excited to ##$% it up again as its 3pm and see some blue sky

Edited March 5 by TiffsAndAstro

[AstroMuni]

8 minutes ago, TiffsAndAstro said:

so after doing a second pa i looked in information:

id=2'28.5' ch=00.0' np=00.0'

mel=00.1' maz=06.4 tilt=03,8'

This post may help https://www.cloudynights.com/topic/639135-synscan-goto-alignment-precision/

[AstroMuni]

13 minutes ago, TiffsAndAstro said:

I'm on a phone atm and I'm old

Anyone who can use a phone to respond in forums is still young... ha ha 

17 minutes ago, TiffsAndAstro said:

Synscap app wont let me doing an in app polar alignment until it has mel maz values from a 2 or 3star alignment.

After doing a 2/3 star alignment the synscan app is trying to tell you how far off you are from a perfect polar alignment. If you find you are way off then start the process again (without using the hand controller). I wouldnt worry too much about it if you have visually checked the location of polaris in the clockface. I never get perfect PA and can still manage to get decent images without star trails. So dont worry.

Edited March 5 by AstroMuni

[TiffsAndAstro]

3 minutes ago, AstroMuni said:

This post may help https://www.cloudynights.com/topic/639135-synscan-goto-alignment-precision/

Fantastic link ty.

Will follow you steps if clear tonight, but will also do a polar align in app after I do a two star alignment.

I might also try a 3star alignment as its possible  my mount is using a cone error from my last 3 star alignment, some time ago, which I may have botched.

 

 

[StevieDvd]

Okay just to clarify a few of your issues:

The spike Malc refers to is the azimuth pin as shown here  and which the azimuth bolts push against to adjust your PA.

I read the manual of Syncan App and it is correct in allowing a further PA after a star alignment. This is only possible as it records the mel/maz settings which is stored for 'adjustments' needed to correct your goto.  

[TiffsAndAstro]

3 minutes ago, AstroMuni said:

Anyone who can use a phone to respond in forums is still young... ha ha 

Worse is using specs to look through polar scope.

Oh yeah and my back. Asi air looks more tempting by the day, but I might have a play with nina first on a laptop.

[TiffsAndAstro]

Just now, StevieDvd said:

Okay just to clarify a few of your issues:

The spike Malc refers to is the azimuth pin as shown here  and which the azimuth bolts push against to adjust your PA.

I read the manual of Syncan App and it is correct in allowing a further PA after a star alignment. This is only possible as it records the mel/maz settings which is stored for 'adjustments' needed to correct your goto.  

I'm really sorry I did work out what he meant. I didn't get the optional mount as it looked no sturdier than my random brand tripod so I dont have an az pin.

[StevieDvd]

8 minutes ago, TiffsAndAstro said:

I'm really sorry I did work out what he meant. I didn't get the optional mount as it looked no sturdier than my random brand tripod so I dont have an az pin.

Then how are you adjusting the mount in azimuth?????

I see from your other posts you have mentioned a SW Gti is it this one

That has the azimuth pin in the base of the mount so you can't see it and it allows the use of a 3/8 tripod.

Edited March 5 by StevieDvd
correction