CGX mount alignment

Hi Markus,

Given your description, I assume you are talking about polar alignment?

There is no way around that when you set up your mount, you have to place the tripod such that it is already oriented towards north within a few degrees. Also make sure it's leveled (when it's nicely leveled, the Alt adjustment will be minimal from setup to setup). Hence, bring a compass with a bubble level included.

The next step depends a bit on your mount. When I'm placing my mount on the tripod, I'm setting the Azimuth knobs such that I am centered with the tripod direction. Now, it depends on the way your mount does polar alignment. Some have a polar scope or polar alignment camera. Follow that according procedure but if you had the tripod set up in the way I described above, you'll only have to make a little Az adjustment (certainly within the limit range of the "knobs" ) and most of the times I have to do only very little Alt adjustment.

CS!

Björn

Hi Markus,

My best compass is the one that came with my Meade LX85 mount and OTA. In the beginning it looked cheap to me (don’t be distracted what vendors want for it) but now, after I have tried a more dedicated compass, I value my „Meade“ compass. The needle is more than 10 degrees wide but it’s accurate and I am always within the limits of my mount‘s Az adjustment range (I think it’s +/-6 deg). 

I also tried to see how the smartphone competes but sometimes North is here then there. Long story short: before you buy a new compass test the current one.

Clear skies,
Björn

Hi John!

Many thanks for your answer! It's a good idea to move the tripod close to Polaris while looking through the finder, but…  I believe I haven't understood every thing about the alignment: can I aim Polaris through the finder without having made an alignment first? With your idea, what would the sequence be, or at which stage should I aim Polaris?

1) installing the mount, levelling and orienting it to N
2) installing the equatorial head
3) installing the telescope with the finder (and Laser pointer)
4) And what's next? Quick align and then looking for Polaris? Or just moving to the home position and then aiming Polaris?

Kind regards

Markus

Hello Markus  

Markus:
Hi John!

Many thanks for your answer! It's a good idea to move the tripod close to Polaris while looking through the finder, but...  I believe I haven't understood every thing about the alignment: can I aim Polaris through the finder without having made an alignment first? With your idea, what would the sequence be, or at which stage should I aim Polaris?

1) installing the mount, levelling and orienting it to N
2) installing the equatorial head
3) installing the telescope with the finder (and Laser pointer)
4) And what's next? Quick align and then looking for Polaris? Or just moving to the home position and then aiming Polaris?

Kind regards

Markus

Hello Markus

First you need to make sure you have your scope and finder scope aligned properly. Sometimes this is easier during the day with an eyepiece. Find a far away object and align both scopes on it. At night find a bright star or planet and fine tune the alignment. Once both scopes are aligned don't touch it any more. leave it on your scope.

Make sure you mount is in the center of the slots. I do not tighten these down all the way. I just leave them snug.

Now assemble the mount and place the scope on it. Once the mount and scope are fully assembled move it so the front leg is facing North. Any compass will do, it does not need to be perfect at this point. Most compasses indicate magnetic north and true north is slightly off of that. Soon enough you will be able to find Polaris easily and you wont need a compass.

Turn your mount on and make sure it is in the switch position. CGX asks you if you want to got to switch on start up so just do it when the hand controller wants. The English version says Switch Position it may be different in translation. I also have a Home position but that is adjustable and not necessarily at 0* in both axis's, though it usually is set that way at the factory.

Here is where you maneuver the mount into position. Do not use any adjustment knobs or buttons, you can even turn the mount off for this. Take the mount by the legs and gently move it around until Polaris is near the middle of your finder scope. Now you should be close enough that your polar alignment will work. If you still run out of room in the slots while you are polar aligning then give the mount a little nudge in the direction it needs to go. You may need to use the altitude knob for also.

Use your cameras live view to polar align. You should polar align before you do the star alignment. I would recommend using Sharpcap if your camera works with it. The polar alignment tool in Sharpcap is quick, easy and worth the nominal fee for that feature alone.

If you are using Celestrons all star polar alignment routine in the hand controller you have to Star align first (do the simplest alignment possible for the first step), Then polar align, Then do a full 3 star alignment with all the calibration stars. Some people say you should actually do a second polar align but I never had the patience for that. Celestrons software works OK, but no where near as good as some of the other camera based solutions available.

Hope this helps and if you need any advice on the CGX feel free to reach out to me. It took me some time to get used to my CGX and it needed some adjustments but I am very happy with it now. 

Cheers
John

Hi Markus

Extending John's comments: "Magnetic declination" is the term for the difference between true North and magnetic North. It's about 3 degrees for Zürich.  Left or right?  Doesn't matter I wouldn't use a compass :-)

As in a previous response, you should man handle the whole mount and move the whole tripod and head initially.  I use the drift method to adjust the mount; have tracking on and look at a star near the meridian and with declination less than 30 degrees and use a high power eyepiece and see how it drifts up or down over a few minutes, and this tells you if you're left or right of North.  This azimuth adjustment works even if the polar axis elevation is not accurate.

I have the same mount and I leave it outside (covered) to avoid the agony of PA. 

Cheers Rod

Regarding Celestron's All-Star alignment and doing star alignments after, note that the manual says to undo the synch first. My newbie understanding is that the mount records the off-set between where you align the mount on a star and where that star should be if the mount were polar alinged. Then once you re-align the mount alt/az, the software uses that off-set against the 'map' it created from the pre-PA star alignments to accurately slew.

I also use the Precise GoTo function which seems to work well.

Cheers,
Scott

Your issues seems to be that you aren't properly accounting for magnetic declination. That is the difference between magnetic north and true north. There are lots of ways to determine the magnetic declination in your location. Here is one:

https://www.ngdc.noaa.gov/geomag/calculators/mobileDeclination.shtml#WMM
​​​​​​A compass that shows degrees in the sight glass makes this easy. I use this one:

https://www.amazon.com/Sportneer-Military-Lensatic-Waterproof-Shakeproof/dp/B01MY6VVWU/ref=mp_s_a_1_3?dchild=1&keywords=compass+hiking&qid=1617798053&sprefix=compass&sr=8-3
The hard part is that you cannot be close to the mount because the motors will distort where the compass is pointing. Get yourself a straight dowel rod that is around 3 or 4 feet long. Before you set down the tripod line up the dowel rod using the compass. But not to magnetic north, to the angle of your magnetic declination. Ex: my mag. dec. is -9.7°. Open the compass completely flat. Looking through the sight glass in the bottom of the compass I rotate to 9-10deg then look down through the target area of the compass and use the cross hairs to align the dowel perfectly. Now set the front leg on the tip of the rod and align the center post to be right over the top of the rod. Now set your mount on the tripod and move the az bolts to the center of the slots. You will be very close and well within the range of the adjustment bolts.

Personally I found the celestron alignment just ok. I used a polemaster to get close and then drift align to really refine the PA, but just a polemaster may be good enough depending on your focal length and exposure time. 

Hope that is helpful.
Tim

Forget all compasses, digital or otherwise. Use the Sun, a straight rod, a weight and a string. And your place's time equation so you know when the Sun is exactly at noon thus crossing the meridian. Stick the rod into the ground at an angle. Tie the string to one end and the weight to another. The string will cast a shadow crossing both your swivel point (normally a peg or a screw) and the peg were you azimuth knobs will push against when stationing the mount. Adjust the mount so that the shadow crosses in the middle of these two points. You are all set for a proper pole alignment and not to fear hitting the buffers when adjusting the azimuth knobs.

Hi friends!

Wow, so many thanks for these answers! I didn't think at the difference between the magnetic and the true North, and this certainly is the reason for my troubles. Why does a manual not mention this… I have downloaded ab app on my phone and saved the NOAA Foield Calculator as a bookmark on my computer.

I'm looking forward to setting up my mount soon!

Kind regards

markus

Hi Markus,
I don't know if this was covered in all the post, I have not read them. I use 3 long 1 foot nail in the ground to position my scope.
Then, I am almost at polaris, and my setup requires one slight bolt turn in dec and az.

Clear skies!
Richard

Glad you got it sorted out!