Polar alignment - NEQ6 pro

[lnlarxg]

Hi, Please please please need some help on my NEQ6,  its more about polar alignment on goto EQ mounts in general probably.  Please allow me to list all the things I have done because l really want to know if I have done anything wrong during my polar alignment....as my goto can't find anything  . It was last night 14th oct, my first time ever with clear sky with my first ever outdoor dressed rehearsal with my NEQ6 purchased circa 4 was ago

so I did the polar alignment, i.e. I levels the whole mount first (i.e. Using a spirit leveller to make sure I have the home position of the mount 99.999% correct), found Polaris somewhere in my polar scope, centred it on my reticule cross hair, used the NEQ6's altitude (so I am only adjusting the mount vertically) nob to move Polaris on to its orbit (printed in the polar scope sight) around NCP, rotated the polar scope around its RA so the Polaris circle has Polaris inside. Rotated the polar scope again so the RA clock on the mount reads polaris's last transit (a read out from my NEQ6 handset's Hour Angle reading, verified with my polar align iOS app), and finally using both my Alt & Az bolts to again place Polaris within the Polaris circle printed out in the polar scope sight.  By the way, I did all of this while the mount is switched on, mainly because I need the polar scope to have the LED on, and the handset to tell me the HA of Polaris 

anything wrong so far? So I at that point turned off my mount,  my telescope was at a strange and awkward angle.  I returned the mount to the home position by disengaging both clutches of RA and Declination  (i.e. Manually returning my telescope pointing straight up).

i then turned my mount back on, re-entered all the date/time/long&lat...etc, then did a 2 stars alignments , chosen my 1st star (Vega) , the mount started to slew and BOOM....., only that it ended up pointing towards something completely different.....:( 

i was very saddened... because that whole process took my novice self good 30-40 minutes, only to find I probably did soemthing wrong.

experienced SGL'ers, help me! All I want it to take some short light frames so I can start enjoy astrophotography like your guys ?

 

 

 

[alacant]

7 minutes ago, lnlarxg said:

re-entered all the date/time/long&lat.

Hi. Your polar align wouldn't cause that. I think you've entered the date in the wrong format. It's MM DD YYYY so today is 10 15 2017 and daylight saving activated. Worth checking? HTH.

[red dwalf]

you certainly don`t need to level the mount perfectly flat, there is no need, and as above, the day date should be in the american format

[paul mc c]

Are your own co-ordinates correct on the hand set.

[Owmuchonomy]

Polar alignment and GoTo mapping are entirely different.  Just check the parameters you entered for the star alignment are correct as stated above including your GPS coordinates.  Your scope shouldn't be pointing straight up before alignment.  Make sure your counterweight bar is pointing down. In this position and if you have polar aligned then the scope will be roughly pointing at Polaris. 

[red dwalf]

also first star will be off somewhat, you then need to slew to it and sync it, then onto the second star

 

[Paul M]

There is more to the Home position than just the physical parking position.

Unless you have already aligned synscan (as different to polar alignment) the scope does not know where it is in RA.

For temporary and portable set-ups you can ignore the home position.

Do as you have done so far but when it slews to Vega or whatever you chosen star,  either manually slew the scope with the handset to actually centre Vega in the eyepiece or if it's really miles away, undo the clutches and slew it by hand with fine tuning on the handset after tightening the clutches again. Press accept and chose you next star, that should now land within your field of view, adjust with the handset to centre it if not already there and accept. 

If you are only doing 2 star alignment you will hopefully get an alignment successful message.

I usually do 3 stars but the third star usually lands bob-on anyway, and I'm rough, really rough at aligning!

Synscan is a great and very forgiving system once it knows where it is pointing. 

[ronin]

Not sure but the "home position" sounds a little odd, maybe it is just the way it is described.

Cannot see it being the date as the would mean you entered the 10 day of the 14 month and there are not 14 months. I think the handset would just ignore the 14 month input, well I hope it would or it would throw it out and you would have to enter a valid month.

Be careful of mixing polar alignment and goto alignment terms and actions up. Easily done.

Data is the obvious, you longitude is going to be East or +ve, most of use are West or -ve. Double check the timezone, seem to recall someone said it had to be -00, also the standard DST, that is still Yes or On.

[Cornelius Varley]

The first star alignment can sometimes be off. Assuming everything else is ok ie time, date, coordinates, home position (telescope pointing at NCP, counterweights pointing straight down), you can improve the accuracy of the first star alignment by doing a one star alignment, allow the mount to slew to where it believes the star is and then release the clutches and manually centre the star. Relock the clutches and accept the alignment (press enter on the handset). From there return the mount to the home position by selecting park mount from the handset menu. Once the mount has stopped slewing switch off and release the clutches again, manually returning the mount back to the correct home position. Retighten the clutches and switch the mount back on. Re-enter the correct date/time info and now do a one star alignment. The mount should now slew closer to the alignment star.

[newbie alert]

Sounds like somethings amiss but don't worry it's easily rectified.couple of things to have straight in your mind first..star alignment and polar alignment isn't the same thing, polar aligning is to do with aligning to the earths axis..star alignment is to tell the mount where it is and makes the goto accurate..

A couple of things sound a little strange..you say you returned the mount to home with the scope point straight up? Now not sure totally where you live (says Essex on your page) we're  at 52 degrees in this part of the UK which means the scope should be pointing at that figure..also make sure you have entered the lattidude/longitude right on the handset and date/time in the American format..

2 other things..your polar scope may need collimating and the setting circles aligning..look on u tube..

[lnlarxg]

Thanks all for the replies, when I said scope is straight up apologies I meant it is pointing in the direction of NCP with both RA and Dec clock at 0, ie home position

will check all coordinates and manually slew to the first star during star alignment, hope he next clear sky is not 6 months away

[Erla]

I had some troubles with the same mount too. As I can't get Polaris in my scope anyway from my home "home" position, I just usually ignore it, and as I can see only very limited sky patch from where I'm usually viewing I just roughly align and then slew it to the patch of the sky I can see to explore it.

Now, the question. 

If the scope is polar aligned, in home position (the controller asks if it is) isn't it in itself one star alignment? At the end of the day, the mount now's my location, time and that it is in home position. On several occasions when asked to go to the first star it went off, very off. I had to stop it and then I just slew. Oddly enough, it tracked the star or other object reasonably well. And yes, the date was in correct format. 

You guys say polar and star alignments are different. This confuses me a bit. I thought I'll get it performing on a field with 360 degree view, but now you say these two things are not related, I would like you to elaborate to get a better understanding.

[Cornelius Varley]

Polar and star alignment are not the same thing. Polar alignment relates to the alignment of the mount , which is required for all equatorial mounts, aligning the mount with the celestial pole. Star alignment calibrates the goto systems star model onto the real sky. The home position for the mount (telescope pointing at NCP, counterweights pointing down) is the normal starting point for the alignment, but it is not a star alignment. The goto system needs a known start position so that when the first alignment star is selected it knows where to slew the mount to. It might miss the target initially, it usually does, then the target is centred using the handset. From here the second and third stars can be slewed to more accurately.

[Paul M]

The equatorial mount is designed so that once an object is in the field of view you only need to track it in one axis, right ascension. This is achieved by having that axis aligned with Earth's axis. That is where polar alignment comes in. Long before GoTo was invented we could have a simple motor drive (even clockwork) or hand operated knob on the RA axis that would keep an object in the field of view with minimum effort. It also meant that setting circles could be used to locate objects but in reality setting circles on mass produced amateur mounts are an almost useless novelty. 

It is important that the polar axis is aligned accurately so that only the RA axis need moving to track an object. So we make every effort to do so.

Then came along computerised GoTo mounts. They don't need to be equatorial. AltAz can be driven with a GoTo computer but it's not ideal for astrophotography due to field rotation. On an equatorial mount the computations are made on the basis that it's polar aligned but that only tells the mount how to expect the sky to move and not where in the sky it's pointing. Somehow the position encoders on both axes need to be "aligned" with a couple of points in the sky to inform the computer where the telescope is pointing.

That is exactly what 2 or 3 star aligning achieves. The mount needs to know your geographical position, your time and where the telescope/mount is pointing. Then it's away! If it's fully aligned and then placed in the home position and not disturbed it can be powered down and then GoTo operation resumed without re-alignment next time you use it. It looks at elapsed time since power down and calculates where the axes should now be pointing. But for "home" to have any meaning it needs to be place in "home" from a known position.

Polar alignment is the mechanical process of getting the mount aligned with Earth's axis. Star alignment gives the mount's software a positional fix on the sky.

 

[newbie alert]

8 hours ago, lnlarxg said:

Thanks all for the replies, when I said scope is straight up apologies I meant it is pointing in the direction of NCP with both RA and Dec clock at 0, ie home position

will check all coordinates and manually slew to the first star during star alignment, hope he next clear sky is not 6 months away

I'd check your coordinates..ive not tried to manually slew to the first star but switching off and then back on I can't see that working myself..

You sound like you got the hang of the ncp etc..

[spillage]

Imagine a pole running through the earth from the south to north pole. This is what we are polar aligning the mount against so the pole and our mount are parallel. This allow the mount to rotate in RA correctly. This is why the angle of the mount increases the further north or south of the equator you go due to the curve of the earth.

When we align the star we are just getting the software to work out where in the sky the mount is pointing, this info is not kept by the handset and needs to be done each time it is switched on.

[Cornelius Varley]

1 hour ago, newbie alert said:

I'd check your coordinates..ive not tried to manually slew to the first star but switching off and then back on I can't see that working myself..

You sound like you got the hang of the ncp etc..

You can improve the accuracy of the single star alignment by following the steps I laid out.

1 Set up mount as normal

2 Enter correct date etc.

3 Select 1 star alignment and select star to align on.

4 Allow mount to slew to star and where ever it stops release the clutches and move the telescope onto the target star. Retighten clutches and press enter to accept alignment.

5 Send the mount back to the home position using the park command. Where ever the mount stops switch off and release the clutches and move the telescope back to the correct home position, retighten clutches.

6 Switch on and repeat the star alignment. It will be more accurate this time.

[lnlarxg]

I found this website which really is well written 

http://www.myastroscience.com/polaralignment

I blame synta or whoever owns Skywatcher for printing manuals that don't make much sense

[Paul M]

4 minutes ago, lnlarxg said:

I found this website which really is well written 

http://www.myastroscience.com/polaralignment

I blame synta or whoever owns Skywatcher for printing manuals that don't make much sense

I must agree that the box standard manual is by far the weakest aspect of the Skywatcher products I own!

[newbie alert]

1 hour ago, Cornelius Varley said:

You can improve the accuracy of the single star alignment by following the steps I laid out.

1 Set up mount as normal

2 Enter correct date etc.

3 Select 1 star alignment and select star to align on.

4 Allow mount to slew to star and where ever it stops release the clutches and move the telescope onto the target star. Retighten clutches and press enter to accept alignment.

5 Send the mount back to the home position using the park command. Where ever the mount stops switch off and release the clutches and move the telescope back to the correct home position, retighten clutches.

6 Switch on and repeat the star alignment. It will be more accurate this time.

I will try this but my head says differently!!

[newbie alert]

8 hours ago, newbie alert said:

I will try this but my head says differently!!

Thinking of it ,no i wont as if im releasing the clutches im no longer polar aligned..

Think I'd rather have the star a little off the first time

[spillage]

2 hours ago, newbie alert said:

Thinking of it ,no i wont as if im releasing the clutches im no longer polar aligned..

The clutches have no connection to polar alignment. The part of your mount with the polar scope is static and will only move if you physically move it either with the adjustment bolts or re position the tripod. 

[Cornelius Varley]

11 hours ago, newbie alert said:

I will try this but my head says differently!!

The concept for doing this is to increase the accuracy of the star alignment. The theory is that the mount starts from the home position and then slews to where it thinks the first star is.  Where to mount stops slewing is usually nowhere near the star so you need to adjust the mount using either the handset or releasing the clutches and adjust the mount manually then retighten the clutches and then pressing enter to accept the alignment. By following the procedure I laid out you can improve the alignment accuracy of a 2 or 3 star alignment. Basically, it resets the home position of the mount. This does affect polar alignment, only the goto pointing accuracy.

[Starlight 1]

8 minutes ago, Cornelius Varley said:

adjust the mount manually then retighten the clutches and then pressing enter to accept the alignment

Am I right in saying you can only do this on Star 1

[carastro]

I think the original poster's polar alignment routine is fine, I am sure it is just something in the data input that is wrong.  i.e. Date, time, location, etc etc

Personally I can never see how manually moving the mount by releasing the clutches is the right way to go, it will then alter the home position (OP it won't alter the polar alignment).  Surely the right way is to manually centre the star by using the handset/or EQmod (if necessary by slewing) until it is centred.  

Carole