Topics

Polar Alignment


Scott Budd
 

Hello all. I just received my new EXOS2-GT Equatorial Mount with PMC-8 and an ES ED80 to go with it. Now I am a Dob guy and this is my first GEM. Polar Alignment, can someone point me to instructions specific to this mount or explain it a little better for me. I found many videos on youtube how to do a polar alignment but none of them are with the EXOS2. The view through my polar scope looks completely different than the view through the scopes on the videos I watched. Am I supposed to make sure Polaris is inside the small circle on the line between the 40' and 60' in my polar scope? Should I do a polar alignment before I plug in the PMC-8s power? Pardon my ignorance but this is the first time I have ever used a GEM.


 

 


Robert Huerbsch <bobhuerbsch@...>
 

Download Polar Scope Align app for your phone, that will tell you where Polaris should be in the circle based upon your GPS coordinates and time. You also need to calibrate the polar scope during the day time. Get the polar scope focused on an object far away. I use a cell phone tower that’s about 1/2 a KM away. Rotate the polar scope and adjust the collimation screws until the the circle moves in the same place instead of rotating in a non circular pattern. If you are lucky the PS will already be collimated. Mine took 20 min to adjust. After collimating it then at night put Polaris in the spot that the iPhone / Android app tells you. I would follow that up with a quick drift align since you should already be pretty close.


David Pickett
 

At 22:05 03-11-17, sbudd4u71@... [ESPMC-Eight] wrote:

Hello all. I just received my new EXOS2-GT Equatorial Mount with PMC-8 and an ES ED80 to go with it. Now I am a Dob guy and this is my first GEM. Polar Alignment, can someone point me to instructions specific to this mount or explain it a little better for me. I found many videos on youtube how to do a polar alignment but none of them are with the EXOS2. The view through my polar scope looks completely different than the view through the scopes on the videos I watched. Am I supposed to make sure Polaris is inside the small circle on the line between the 40' and 60' in my polar scope? Should I do a polar alignment before I plug in the PMC-8s power? Pardon my ignorance but this is the first time I have ever used a GEM.
Sorry, I dont have an EXOS, so I cant tell you how its inbuilt polar alignment works; but I can tell you that normally it is expected that you do a polar alignment before using ExploreStars. This aligns the RA axis with the axis on which the Earth turns, and thus enables a GEM to track stars using the RA motor only. Without this alignment, or with an ALT/AZ mount, both motors need to be adjusted to keep a star in the middle of the visual field.

However, for visual, as opposed to photographic observing (and to get your feet wet), you should find it sufficient to do a three star alignment in ExploreStars, the only problem being that you do have to have an approximate polar alignment of your system when the scope is in park mode or PMC will not get anywhere near the alignment stars. If you get Polaris in the middle of your polar scope this may be good enough. There is also the opportunity to sync on any star if it does not appear in the center of the field of view after a GoTo. To do this, use the joystick controls to centre it and then hit "sync".

It would be good for you to practice the polar alignment of the EXOS. Over time, you will get more adept at it and the GoTo will be more accurate. This is the process most people go through.

David


Wes Mcdonald
 

So after much fooling around with polar alignment using polar scopes I concluded I am a clod and likely to remain so when it comes to this.  In the end, I bought a PoleMaster from QHY.  This thing is the exact thing you need to get polar aligned with ease, no back breaking fidgeting sitting under your mount trying to see through the polar scope and all that.  It is pricy, but this is the one astronomy accessory which is not strictly necessary but which I wouldn't be without.  If you buy one, be sure to get one with the GEM adapter (it mightbe standard, can't remember) which works fine on the EXOSII PMC-8 rig.  I think Explore SCientific has them for sale, as do many other vendors.

Being new to the ExoStars app on the Windows 10 tablet, I have not yet tried to run the Polemaster software on the tablet yet - I run it on a MAC I use for most things.  But I would be surprised if it does not run under Windows 10.

Regards,
Wes.

 


David Pickett
 

At 19:34 04-11-17, wesmcd6@... [ESPMC-Eight] wrote:

So after much fooling around with polar alignment using polar scopes I concluded I am a clod and likely to remain so when it comes to this. In the end, I bought a PoleMaster from QHY. This thing is the exact thing you need to get polar aligned with ease, no back breaking fidgeting sitting under your mount trying to see through the polar scope and all that. It is pricy, but this is the one astronomy accessory which is not strictly necessary but which I wouldn't be without. If you buy one, be sure to get one with the GEM adapter (it mightbe standard, can't remember) which works fine on the EXOSII PMC-8 rig. I think Explore SCientific has them for sale, as do many other vendors.

Being new to the ExoStars app on the Windows 10 tablet, I have not yet tried to run the Polemaster software on the tablet yet - I run it on a MAC I use for most things. But I would be surprised if it does not run under Windows 10.
Actually, someone who can see the merits of a Polemaster is hardly a clod!

I also got one of these for my G-11. The weather has been too bad for me to be able to get out to use it yet; but it is obviously a high quality product and many others have recommended it. Installation was simple and the software runs fine on my Windows 10 laptop -- though not having a Windows tablet, I cant speak for one of those.

David


Michael Fulbright
 

For anyone with a guidescope and supported camera and about a ~1 degree FOV you can use Sharpcap to use the same process without having to buy additional hardware.

Also the latest betas of PHD2 have a similar function.

Polemaster is great but using your existing hardware to do the same thing is sweet too.

Michael Fulbright


On 11/4/2017 4:38 PM, David Pickett yahoo@... [ESPMC-Eight] wrote:
 

At 19:34 04-11-17, wesmcd6@... [ESPMC-Eight] wrote:

>So after much fooling around with polar alignment using polar scopes
>I concluded I am a clod and likely to remain so when it comes to
>this. In the end, I bought a PoleMaster from QHY. This thing is
>the exact thing you need to get polar aligned with ease, no back
>breaking fidgeting sitting under your mount trying to see through
>the polar scope and all that. It is pricy, but this is the one
>astronomy accessory which is not strictly necessary but which I
>wouldn't be without. If you buy one, be sure to get one with the
>GEM adapter (it mightbe standard, can't remember) which works fine
>on the EXOSII PMC-8 rig. I think Explore SCientific has them for
>sale, as do many other vendors.
>
>Being new to the ExoStars app on the Windows 10 tablet, I have not
>yet tried to run the Polemaster software on the tablet yet - I run
>it on a MAC I use for most things. But I would be surprised if it
>does not run under Windows 10.

Actually, someone who can see the merits of a Polemaster is hardly a clod!

I also got one of these for my G-11. The weather has been too bad for
me to be able to get out to use it yet; but it is obviously a high
quality product and many others have recommended it. Installation was
simple and the software runs fine on my Windows 10 laptop -- though
not having a Windows tablet, I cant speak for one of those.

David



Keith Krayanek
 

I have the EXOS with PMC-Eight and got a Pole Master. I find it takes about 5 - 8 minutes at most to do a polar alignment. The hardest and longest part is tightening down the adjustments knobs and still be aligned. It will move the final alignment off a little bit upon tightening. It takes a few try's of adjustment, tightening, loosening, readjusting before you are good and tight and still aligned with the pole master program. First couple of times it took a while, but you will get it down under 10 minutes in just a couple of times.

PHD2 usually says I am about 1.7 arc minutes or under with the pole master.

Good Luck!

Keith Krayanek


W. Christopher Moses
 

I have the G-11 PMC-8.
I'm not sure I could even do a polar alignment by hand anymore.  I've been using the POleMaster since not to long after it came out (with my Ieq45) and have never looked back.

One thing that people should keep in mind is that the required polar alignment accuracy and the drift of a given sub exposure time are directly related.

If anybody wants the math, or a little program I wrote to compute such things, let me know.


W. Christopher Moses
 

Other than rare circumstances, I will never go go without a POleMaster again.  Sure there is something Primal about doing a drift alignment to within .000005 arc seconds.  But is there any point to it?  For visual, obviously not.  Is there for photo?  Well, it depends. THere is a well established relationship between such parameters as:

Subexposure time
Focal length
drift
guide camera location
time
Pixel count and size

I see so many people optimizing their PA and then shooting 1 minute subs  with a 100mm scope! Or shooting with a 1000mm fl sct and not knowing the limiting duration of their subs and camera.

I'm not criticizing, I'm just saying that PA is not the be all and end all of setting up a scope. In my opinion, in the near future, getting the minimum required PA for a particular set-up will become standard.  I could easily see PhD, SharpCap and PoleMaster building in some such metrics.

OK, maybe I am ranting a bit...lol


W. Christopher Moses
 

Keep in mind that there is a difference between PA  and star alignment/pointing accuracy