Re: 2/3 Star Alignment, possible to select the stars to align? #ExploreStars #alignment

Wes Mcdonald


The short answer to your question is no.  You just have to keep going to the next star until the windows app picks the one you want.  The iPad app also works in this manner.

The Android Explorestars app however lets you pick your alignment stars.  You start the alignment process and go to the catalog menu from which the target star may be selected.   

If you decide to use the Android app and get a tablet running Android 10 or newer be sure to load the app from the link on the Explore Scientific web site, as the one on the play store does not support the newer OS version.   It would be best probably to buy a used tablet with an older version of Android on it.  

You can research other means for doing polar alignment on the internet.  Drift alignment is an example of such, and starting from a rough polar alignment given by PSALIGN it should be pretty quick once you get the hang of it.   This will give you a good physical polar alignment, after which there is no need for a 2/3 star virtual one.

The Android and iPad apps are superior to the windows app, as various features have been added that aid in use.  One of the main features is these apps allow you to prevent the mount from taking off to the next alignment star or any target for that matter until you press the goto button.   Thus when you are cycling through alignment stars looking for one you have visibility for the mount will not be doing crazy slews all over the place.   

Be aware that the 2-3 star alignment only creates a virtual alignment.  This means that while the thing can find objects it is not necessarily polar aligned.   The software continuously computes the required ra and dec motor position (5x per second) and moves the mount continuously.  This will lead to a bit of jitter in your images and might also cause the objects to rotate in the field of view during a timed exposure.   This occurs when the triangular mode indicator shows the letter P for point mode.   When the indicator shows T for track mode the mount ra motor runs smoothly at sidereal rate while the dec motor is stopped.   This is what is needed for the best astrophotography, however for imaging purposes the mount will need to be mechanically polar aligned.   This is where drift alignment or some other method comes in for you.  

In the windows app I believe the mount, after a goto slew, is put into the P mode.  To get it into T mode you must press one of the left/right/up/down buttons.  You can set the rate to 1 and bump one of the buttons and you will be in T mode.   Doing a goto again to the same target will put you back into P mode.  I think.   I don’t use windows Explorestars anymore and might be wrong but the gist is correct.

In both the Android and iPad apps the triangular indicator is also a button which can be pressed to easily transition the mode back and forth between P and T.  This is another reason they are superior, in my view.

You probably should connect up your mount via the serial connection and find out what version of code you are running.  You can do this from the Configuration Manager program available from the Explore Scientific web page.  Use it to send the ESGv! Command.  If you are not running the latest firmware in the mount I suggest you upgrade using the install kit and following the included instructions found therein.  The kit is available from a link on the explore scientific web page.  All you need is a proper usb cable and (very important) a usb-to-serial converter driver installed on the windows box.  Suggest you load the one that can be found on the parallax web site.   It works well.  Your version should be 20A01.02 or higher (.03,.04, etc).  I would be very interested in knowing which your mount came with, especially if you bought it new.  The older versions for the iexos were something like 1Axxxxx. 


Wes, Southport NC
EXos2-GT PMC-8, iExos 100
ES ED 127, 10" LX200GPS+wedge, Astro-Tech 8" Newt, ETX-90, 60mm no-name guide scope ~ 260mm FL
Polemaster, Orion ST-80 and SAG, ZWO 290MM, D5300 astro modified
Nina, Bootcamped Mac Mini control computer, RDP to iMAC
110 amp hour lead acid deep discharge battery for field power
Electrical Engineer, Retired

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