Polar aligning an HEQ5

[AstroFrog]

Good morning all,

You were very helpful (as always!) recently, when I asked for advice after a friend had asked me to help him set up is new shiny HEQ5 pro synscan.  Having only ever used my little alt-az mount, I was stumped, but you guys came to the rescue, for which I was extremely grateful!

 

Now we’re teaming up again to try and get more precise polar alignment so that we can start doing some longer exposure astrophotography.  However, it’s proving mighty tricky, so I was hoping I could trouble you with another few queries.

I had seen that Astro-baby’s tutorial came highly recommended, so we gave it a shot, but we weren't quite sure about a few things…it comes to something when even the ‘idiots guide’ has the two of us completely stumped!

 

1. So the final step of polar alignment is to get Polaris in the tiny circle in the reticule, which has been set up to be in the perfect (hopefully) position for Polaris’ movement around the North Celestial Pole.  So the angle that the mount is at right now, e.g. with the scope at the 9’o’clock position and the counterweight bar at 3 o’clock – do I start from that position if I wanted to do a 3 star align now for goto accuracy?
2. At what point do you power up the mount?  Before you start polar aligning or once completed?
3. Does it matter where the declination axis is during polar alignment?
4. If I PA, and then wanted to do a 3 star alignment (for example) – The telescope should start by being absolutely centred on Polaris?  Or presumably just slightly off set  (Thus ensuring the alignment of the mount and the scope are the same?)  So I’d need to move the declination axis only, until Polaris was near-centred?
5. Should the mount slew the scope to the exact location of the alignment stars, if all of the above has been completed correctly, and the mount is level?
6. Do I keep the RA circle/clock locked in at ‘0’ from that point onwards for the rest of that imaging session? Or do you unlock it?
7. I use the http://aa.usno.navy.mil/data/docs/mrst.php website for Polaris transit times, which I saw linked to on here recently – I trust that’s a reliable source?

 

 

Many thanks for any help you can offer!

 

Fred

[Owmuchonomy]

Hi Fred, well done on getting to grips with EQ mount alignment.  I could answer all your queries one by one. However, the objective of your post appears to be to set up for long exposure astrophotography.  If that is the case then I recommend two options.  Firstly, the best method for polar alignment is to use a Drift Alignment procedure.  There are several ways to do this and by all means search this forum for the best.  The second method if you have Synscan is to use the inbuilt Polar Alignment routine from the handset.  Therefore you only need do a rough visual polar alignment with the polar scope then you move on to the handset routine. This will give you much more accurate results. The procedure is described in the manual. I also attach a document here which many users have downloaded and you need to refer to Section E.  Good luck.

HEQ5 Setup - My Step by Step_clean.doc

[ronin]

1: You are polar aligning the mount not the scope, to a fair amount forget the scope. You can polar align the mount without the scope on, many do as it means less weight ahd you do not have to dodge the scope and bits, also means less chance of the bolts bending.

You start the Goto Alignment from whatever the start position(s) are defined or offered in the manual.

2: As the power is not required for the Polar Alignment you can take your choice - is the polar scope illuminated from the mount? If so then apply power before Polar Alignment. I half think that at some stage you need to power off the mount, you used to have to on one of them.

3: No idea, getting confused with all the terms being used. I suspect the Polar Scope is independant of the Dec angle. That will be for the scope not the mount. Again seperate the 2.

4: The scope should start from the Goto Alignment start position, Manual. If there is an option for the start position to be Polaris then you centre the scope on Polaris, I would assume that the offset is somewhere in the code for Data and Time.

5: If the/a Goto Start position IS to start centered on Polaris then it should go pretty close, since you have a known start location that is fairly accurately set. Equally the movement depends on the remainder of the data provided.

6: RA is a nighrmare to explain, it is sort of fixed and moves. One way to look upon it is RA is Time and Time moves onwards.

7: No idea.

I think the main thing is to seperate mount from scope when doing whatever.

You are Polar Aligning the mount.

The Goto Alignment is with the scope.

[MattJenko]

It also depends a bit on what sits on the HEQ5. A shorter focal length setup is more forgiving. I have found that a pretty crude PA routine works for me and my ED80, as guiding helps me more than spending more time fine tuning my PA. I use a PolarAlign app which gives me my polaris position on the circle in the polar scope. I ensure the mount is well enough leveled (not essential, but makes things easier) and then I simply use the Alt-Az controls to put Polaris in the circle given by the app. A quick spin around the RA axis will confirm if the star follows the circle and this is good enough for me.

If I had a more permanent setup, then I would absolutely do drift alignments and do them quite regularly. Its all about effort/results.

[Marky1973]

Hey Fred - have you checked out the Astronomy Shed tutorials for an NEQ6 on YOUTUBE - there are a series of that them that talk you through levelling, setting circles, PA and using the handset to align - they are a great guide that I used - although for the NEQ6 the principles are the same and definitely worth a look.

Some other thoughts -

As suggested above - try and separate the scope/mount, you are aligning the mount - once you get the reticule over Polaris and are happy, you can release both DEC and RA and go back to the home position - which will be weights straight down in front and DEC pointing straight up (if there was a scope on it) - effectively it would be 0 RA and 0 DEC during the first stage of setting up - once you have the setting circles calibrated for Polaris and your location, then RA will be whatever it was you set it at - the tutorials I mentioned explain it much better than that!

DEC does not matter during PA - on the NEQ6 it HAS to be rotated or you can't see through the polar scope!!

Point 5 - I've never had it exact, but they are usually close - but that is why you do the alignment - You should also try PAE, which allows you to centre on a bright star near your target and then "lock" the mount in - it should hten know where it is in the sky and make it even more accurate when slewing to your target. - has worked pretty well for me so far!

Point 7 - forget transit times if you use the tutorials above - once you set the circles using his methods, you just switch the synscan handset on and use the display to tell you the PA Hours (once time date is set etc) and rotate RA to the appropriate time - you can use an APP like POLAR FINDER to check that it is in the right position

Think I'm rambling now.....

Good Luck!

[Tinker1947]

I would use the syscan handset PA option, not grubby knee's as you view through the scope/telrad....run it 2 or 3 times on different stars and it will be spot on.....

[AstroFrog]

Unfortunately work has thrown a whole load of extra hours at me, so I'm stuck for time, but just wanted to post a quick thank you to you all for replying, and for your considered and helpful responses - thank you!

I'll have a good read and absorb all this wonderful info at the weekend hopefully, and will respond properly then.

Thanks again and catch up with y'all soon!

Fred

[glowjet]

Your question 7 relates to Polar Transit times, I can`t comment on the website given. There are, however, constants with Polar Transits, that you can use with your setting circles to calibrate the mount, this can be done at anytime, if this is the procedure you are following. Four constants that I know of occur on... 15th Mar at 15Hrs, 15th June 10Hrs, (advanced by 1 hour, daylight saving) 15th Sept at 4hrs (advanced by 1 hour, daylight saving) 15th Dec at 21Hrs. If you want to double check, just put any of theses dates and times into Jason Dales "Polar Finder" program, vary the years and you will see that the Polar Transit says constant