polar align

[Brian1983]

Hi there I have just got a motor for telescope as I want to take longer exposures can anyone give me advice on how to polar align my scope it's a EQ5 mount and tripod 200p scope is it just practice makes perfect? Any advice would be great

 

Brian

[SonnyE]

Hi Brian!

I'll try to bide your time until the cavalry arrives....

I begin by making sure my tripod is as level as I can make it on a stable surface.  I'm so anal about that I use a digital level and work to 0.0 degrees on at least N-S and E-W.

Why? Because it makes a plumb surface for the mount to begin with.  That way when the mount is working, it is beginning at known points and swinging on reliable planes.

Polar Alignment is 'Square One' in the set up. Basically, the mechanical beginning of getting our mounts 'Square with the World', and theoretically on a straight line up.

Getting your Latitude and Longitude, the North Star Polaris is your next aim. Best done with a polar scope. But not an absolute necessity if you can align Polaris through an eyepiece. I used an Illuminated eyepiece with cross-hair's in it when starting out. My first one was a very inexpensive one. It failed miserably the first two weeks I had it. Lesson learned, I spent more and got a great one with a finely adjustable light source. It truly helped having a good illuminated eyepiece.

For your Lat-Long, I just use my cell phone with a GPS app.

Some folks get very persnickety about Polar Alignment. I am NOT one of them. I can understand their points, but I am not willing to fiddle for hours on it. Instead, I do my alignment procedure with my mount. Then do a Polar Alignment per Celestron's directions. Then I can confidently be assured I've done my best to try and get things right before I begin the rest of my night. But I don't do the Polar Alignment procedure every night. It suffices to check my mount has Polaris as close as it was the night before, and forge ahead like a bull in a china shop. Just remember, Polar Alignment is the basis, the mechanical beginning of your alignment.

For targets, and navigating, I recommend Stellarium. You can grow into it running your mount to take you to objects in space.

Have fun! And remember, too, that this is going to add to your skill set and frustration levels. Stiff upper lip!

[Brian1983]

Hey thanks for the tips when we get some clear skies I will give it a go

[ollypenrice]

I take the opposite view to SonnyE in that I think levelling the mount does very little, and levelling it on a N-S plane does nothing at all. (You're going to tip the mount head to the equatorial angle anyway, N-S.) If you use the drift method, having a level mount will reduce the interactions between adjustments in altitude and azimuth, but not by much. We all do as we see fit but time spent on careful levelling would not be a good use of time for me. Tak mounts have no facility for levelling. None whatever!

This method https://www.cloudynights.com/articles/cat/articles/darv-drift-alignment-by-robert-vice-r2760 is a crafty variation on the drift method and is pretty quick. It does work through the camera so you need a good view of the screen and ideally that would be a PC screen.

Olly

 

[johnrt]

My mount is already tipped up by 52 degrees by my location on the surface of the planet before I begin, so what is the point of spending much time levelling it to the ground?

If I was installing one of these I would put the effort in....

 

But for running 5/10 min exposures on a 1000mm focal length 200mm reflector, I think you're better off concentrating getting your polar alignment and balancing as accurate as you can on that mount.

[ollypenrice]

Yes, you are not trying to align your pier to the centre of the earth, you are trying to align your mount's RA axis to the Earth's polar axis. These are unconnected.

Does your EQ5 have a polar scope? If so you first need to be sure it's aligned correctly. Firstly contrive a position for the mount in which you can see a distant point through the polar scope. The apex of a roof, a steeple top, a tree on the horizon... Centre this in the reticle. Now rotate the RA housing. If the cross in the centre of the reticle remains on the target you're good. If it describes a circle relative to the target you need to adjust it with the three little radial screws.

There are various Polaris finding Apps and websites which will tell you the angle of Polaris relative to the celestial north pole so if Polaris is at five o'clock on the App just put it at five o'clock in your polar scope's circle.

Olly

[SonnyE]

Disagree if you'd like.

But the fact that my method works, and works very well, cannot be denied.

"Yes, you are not trying to align your pier to the centre of the earth, you are trying to align your mount's RA axis to the Earth's polar axis. These are unconnected."

Interesting statement Olly. The center of the Earth is not connected?

Ta-Ta Gents.

[SonnyE]

7 hours ago, ollypenrice said:

I take the opposite view to SonnyE in that I think levelling the mount does very little, and levelling it on a N-S plane does nothing at all. (You're going to tip the mount head to the equatorial angle anyway, N-S.) If you use the drift method, having a level mount will reduce the interactions between adjustments in altitude and azimuth, but not by much. We all do as we see fit but time spent on careful levelling would not be a good use of time for me. Tak mounts have no facility for levelling. None whatever!

This method https://www.cloudynights.com/articles/cat/articles/darv-drift-alignment-by-robert-vice-r2760 is a crafty variation on the drift method and is pretty quick. It does work through the camera so you need a good view of the screen and ideally that would be a PC screen.

Olly

 

So because you spent a Kings Ransom on a mount, it makes you right? Okey Dokey....

I'll remember that when poking a pier in the ground. It does not have to be plumb because Olly and John said so. 

[bottletopburly]

Theres more than one way to skin a cat ,which ever way works best for you , at the end of a ten minute sub you`ll soon find out . +1  for ollies comment regarding levelling 

[Alien 13]

If you do widefield imaging with a lightweight mount like me I would say get it level as it takes two minutes, polar alignment with the right app that has a template for your polarscope takes a further two minutes then snap away.

Alan

[ollypenrice]

1 hour ago, SonnyE said:

So because you spent a Kings Ransom on a mount, it makes you right? Okey Dokey....

I'll remember that when poking a pier in the ground. It does not have to be plumb because Olly and John said so. 

Whoa, steady on. No need to fight. What I have to say is based on any mount and you don't actually know what I spent on my mounts since I didn't buy them new. Before I had high end mounts I used budget ones. Nothing changed. Whether or not John and I are right or wrong is based on physics, not cheque book.

Your position on levelling is odd. You say, 'I'm so anal about that I use a digital level and work to 0.0 degrees on at least N-S and E-W.' to level your mount. And then you say, 'Some folks get very persnickety about Polar Alignment. I am NOT one of them.'

So you obsess about aligning your pier/tripod with the centre of the earth but you are casual about your polar alignment. I'm sorry but this makes no sense to me. 

You could pay a king's ransom for a Tak EM400 mount and find that it had no provision for levelling. That's because Takahashi (not Olly or John) understand what polar alignment is about.

Perhaps we should cast an eye over the code of conduct. Stick to the facts.

Olly

PS regarding level piers, don't listen to me. Ours aren't. But I usually work in 30 minute subs. 

Olly

 

[StevieDvd]

There are several methods. It all depends on what equipment you already have and whether you want to spend further - though finally it's whichever way you prefer.

1. Use the mount  - if it has a polar scope (aligned to the mount axis) and working scales

2. Use a camera - various software choices

3. Handset - may have an alignment option (not sure what mount you have)

Levelling the mount can make some procedures easier but I would not over stress it's importance. My static pier is only roughly level and pointing north,  the mount adjuster does the final alignment.

 

 

 

[spillage]

@Brian1983 I would suggest spending as much or as little time levelling your mount. Dont worry this subject always causes both camps to clash. I have tried both and I have to side with @ollypenrice on this one. 

For some it just takes away a possibility of something causing issues.

Are you going to be taking photos or are you just going to observe as this makes a large difference.

If you are just observing then you can just do a rough polar alignment as you would not be on a target for that long. If you are using a camera then lots of options are open depending on your setup.

Maybe if you let us know your set up this will help.

[Alien 13]

I think both views are correct, simple unguided setups benefit from leveling and polar alignment, in fact its critical if you want to ensure your polarscope vertical is vertical when matched to that generated by an app. Guided setups probably like a bit of inaccuracy.

Alan

[SonnyE]

I don't need to throw images around, Olly to prove my point. But I can.

One is the Eagle Nebula in my Profile.  I've done up to 1 1/2 hour OSC images. Just to see if I could. It was a fun experiment.

Advising sloppy workmanship in setting up, then relying on the electronics to do all the compensating, makes no sense to me.

If you don't have a reference to the ball of jello we are trying to image from, there is no mechanical start point. Might just as well nail my mount on the roof, hey, works every bit as well. 

And Takahashi isn't in this thread Sir, you brought that bit in.

I'm saying your reference is out of place in this discussion. By the way, does Takahashi have adjustable legs? And what for? 

Beautiful image of the fireworks galaxy. I have some, but not of that quality.   ...yet!

Just my tacky some odd 75 attachments found hanging in my profile. Oh, here's late one.

But it is amazing I can do that, doing my alignment all wrong.

Because I rarely bother with more than a very quick peek to see if Polaris in in my red dot site before moving right along. And because my mount is plumb, it is there.

Onward through the fog...

[Ant]

Keep it civil everyone.

Yes if you wish to level the mount it makes adjustments to polar align a little simpler IMO.

However it ISN'T required for polar alignment.

The goal is good polar alignment, how you het there is down to You!

Ant

[Tim]

1 hour ago, ollypenrice said:

 

PS regarding level piers, don't listen to me. Ours aren't. But I usually work in 30 minute subs. 

Oly

 

No mine's not level either, but I rarely go over 60 minutes for subs these days, don't want to have to start autoguiding.......

[Alien 13]

It all depends if you are relying on the polarscope for alignment as with a star adventurer or have a secondary system like syncscan to get you aligned.

Alan 

[MartinB]

Sonny, I don't think you are doing your alignment wrong, it was just the strong emphasis on getting the mount plumb level which some people took issue with.  Many tripods incorporate a spirit level and have adjustable legs.  It is sensible therefore to set up nice and level when this is made so easy for us.  However, a level mount isn't a requirement for accurate polar alignment.  I have often used a tak wooden tripod which doesn't have adjustable legs (increasing the overall rigidity of the tripod).  Achieving plumb level with this kit would be a proper pita.  If you are a significant way off level the direction of drift moves away from the vertical but not a huge issue.  Also a level mount makes it easier to get close to correct alt if your mount has an alt scale.  So definitely not a waste of time leveling if you can do it easily.  

Brian, there are numerous ways to polar align using various levels of technology.  However, being able  to quickly and accurately drift align is a skill well worth acquiring.  Starting with the basics, and sorry if this is already blindingly obvious to you but the mount is aligned by correctly adjusting the altitude and azimuth settings of your mount, nothing to do with RA and dec.  Get a feel for adjusting these with a fully loaded up rig.  Sometimes adjustment can be quite stiff and feel clunky.  As Sonny has said, an illuminated reticle eye piece will make life much easier since it makes small amounts of star drift easy to spot.

Here is some detailed advice https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0ahUKEwjXvaeE-97VAhXkC8AKHfjODB8QFggoMAA&url=http%3A%2F%2Fastropixels.com%2Fmain%2Fpolaralignment.html&usg=AFQjCNG3xYWOYiDSrIb1e6ja73b9P_Xx4A

Top tips -

Give some though beforehand as to which adjusters you need to move which way.  Then write down a set of instructions in big type and, laminate this instruction sheet.  If you are anything like me you will tend to get in a muddle.  Knowing which direction a screw adjuster will alter the position of the mount (east/west or up down) isn't always intuitive.  

It can help if you deliberately offset the mount before starting.  If you know that the mount is oriented below and to the east of the north celestial pole (NCP) then you will know from the outset which way your adjusters need to be turned.  

Your initial drift will be quickly apparent.  You will rapidly gain an understanding of how big a correction you need to make for a given rate of drift.  After 2 or 3 drift alignment sessions you will find that you become much faster and should find you can do the job in 20 mins.  

Some people strive for perfection in PA and like to ensure that their alignment stars show no drift for 30 mins or more.  This is very sensible for an observatory mount but you will learn over time how accurate you need to be.  Obviously it depends on how long you need your exposures to be and also the focal length of your scope.  Your scope is not as forgiving as a short focal length refractor but a lot more manageable than a 10" SCT.

Good luck!

 

[ollypenrice]

19 minutes ago, SonnyE said:

I don't need to throw images around, Olly to prove my point. But I can.

One is the Eagle Nebula in my Profile.  I've done up to 1 1/2 hour OSC images. Just to see if I could. It was a fun experiment.

Advising sloppy workmanship in setting up, then relying on the electronics to do all the compensating, makes no sense to me.

If you don't have a reference to the ball of jello we are trying to image from, there is no mechanical start point. Might just as well nail my mount on the roof, hey, works every bit as well. 

And Takahashi isn't in this thread Sir, you brought that bit in.

I'm saying your reference is out of place in this discussion. By the way, does Takahashi have adjustable legs? And what for? 

Beautiful image of the fireworks galaxy. I have some, but not of that quality.   ...yet!

Just my tacky some odd 75 attachments found hanging in my profile. Oh, here's late one.

But it is amazing I can do that, doing my alignment all wrong.

Because I rarely bother with more than a very quick peek to see if Polaris in in my red dot site before moving right along. And because my mount is plumb, it is there.

Onward through the fog...

No, this is precisely the point, it doesn't. It doesn't have them because they are not necessary. Takahashi simply supply legs of fixed length which you plonk down on whatever surface.

Here's a quick sketch to show why the angle of your pier has nothing to do with your polar alignment.

We are viewing W-E here in the N hemisphere. Case 1 is for a vertical pier. But, obviously, cases 2 and 3 share exactly the same polar alignment. You can rotate the sketch through 90 degrees and find exactly the same when viewing N-S or S-N. Indeed some pier makers offer piers sloping south because it allows GEMs to track further past the meridian. Not a bad idea though I've never made one.

At no point have I said that a level mount cannot be polar aligned. What I have said is that a non-level mount can be polar aligned.  That is why I posted an image as proof.

Olly

 

 

[Alien 13]

12 minutes ago, ollypenrice said:

At no point have I said that a level mount cannot be polar aligned. What I have said is that a non-level mount can be polar aligned.  That is why I posted an image as proof.

Olly

 

I dont disagree in principle but if you are relying entirely on the polarscope (which you often do with widefield and simple tracking mount) then the mount has to be level otherwise your reference point for the vertical position of the polarscope will be out, unless you have one with a built in spirit level (some do).

Alan 

P.S. drift alignment would fix this but is a faff.

[Erla]

Pfff... Levelling, drift alignment... Lately I just plonk my mount somewhat level, do not bother with polar alignment at all as I can't get Polaris in my polar scope from my usual spot. Simple ''I think north is there and my latitude is set to the correct geographical place'' does it. And not only for visual!

Behold the results!  

Is it processed, you ask? Who knows! It's a bacchanalia in here!

Sometimes I behave. Then I find being somewhat level (no patience for 0.0 though) helps. Polar alignment - even more helpful. I personally  find it easier to get Polaris by adjusting mount head than fiddling with tripod.

lastReferenceFrame.tif

[SonnyE]

5 minutes ago, Erla said:

Pfff... Levelling, drift alignment... Lately I just plonk my mount somewhat level, do not bother with polar alignment at all as I can't get Polaris in my polar scope from my usual spot. Simple ''I think north is there and my latitude is set to the correct geographical place'' does it. And not only for visual!

Behold the results!  

Is it processed, you ask? Who knows! It's a bacchanalia in here!

Sometimes I behave. Then I find being somewhat level (no patience for 0.0 though) helps. Polar alignment - even more helpful. I personally  find it easier to get Polaris by adjusting mount head than fiddling with tripod.

lastReferenceFrame.tif

Yep.

I'll recall not to visit any skyscapers built but my fellow Star Gazers. 

[ollypenrice]

3 hours ago, SonnyE said:

Disagree if you'd like.

But the fact that my method works, and works very well, cannot be denied.

"Yes, you are not trying to align your pier to the centre of the earth, you are trying to align your mount's RA axis to the Earth's polar axis. These are unconnected."

Interesting statement Olly. The center of the Earth is not connected?

Ta-Ta Gents.

The centre of the earth is a point so it has no orientation. So no, it is not in any way connected with the earth's polar axis other than that the earth's polar axis passes through it. The same can be said for any straight line passing through the earth's centre. The earth's polar axis is a line. It is that line, and that line alone, which really interests us.

21 minutes ago, Alien 13 said:

I dont disagree in principle but if you are relying entirely on the polarscope (which you often do with widefield and simple tracking mount) then the mount has to be level otherwise your reference point for the vertical position of the polarscope will be out, unless you have one with a built in spirit level (some do).

Alan 

Yes, on the regular EQ6/Losmandy etc polar scopes the levelling does set the reticle to the correct angle. But consider the inaccuracies of such polarscopes. You are never going to get an ultra-fine levelling of the mount base to translate into anything useful at the polarscope. The genius of the Tak system is that it ignores the levelling of the mount base and, instead, puts a spirit level on the RA housing connected to a time zone offset. It is this which then sets the orientation of the polarscope reticle. Brilliant. (And, I'm inclined to say, about the only good reason for paying Tak prices for a mount. I won't be buying another one, but their polar scope PA routine is the best there is.

49 minutes ago, Tim said:

No mine's not level either, but I rarely go over 60 minutes for subs these days, don't want to have to start autoguiding.......

I had a few conversations with Per about this, but usually after a hard day's observatory building followed by his favourite drink, chamapagne... (He was a truly lovely and generous guy!) He reckoned that the 10 Micron software (and he wrote it, after all!) preferred a level mount. I know, like Manuel, 'Nothing.' But normal mounts do not need level bases.

Olly

[SonnyE]