Getting Going With a Goto Handset

This is a tutorial for SkyWatcher goto handsets – Celestron have significant stylistic differences but they are substantively the same. You should polar align your mount beforehand.

synscan handsetWhen you connect your handset to your mount and start it up, you’ll be presented with a start-up screen. Just press ‘ENTER’ until it wants you to input information. To input your details use the arrow keys, number keys and ‘ENTER’ to proceed or ‘Esc’ to go back.

There are a few details along the way that can easily trip you up without you realising it, but this guide will allow you to sidestep these and get a good alignment:



The first piece of information your handset will request is your location. This is the first trap too; the world is becoming decimal but astronomy prefers degrees/minutes/seconds. If you use Google Maps or most iPhone apps, your location will be in the decimal format (for example, Trafalgar Square in London will appear as 51.507759,-0.128036, but putting 0.12W, 51.50N into the handset will fool it into thinking you are 28 miles further north and prevent your mount from locking onto your correct position in the later steps). You can convert these decimal coordinates from free websites you can find by putting ‘lat & lon converter’ into Google but this is quite long-winded when a good iPhone/Android app or GPS unit will do this for you. I use the MotionX GPS app to display my location in the correct format, but the ‘Coordinates – Calculate and Convert a Position’ app works just as well.

synscan screen location

In MotionX GPS, go to Menu > Setup > Display > Coordinate Format: DMS > Done > Menu > My Position.

In  Coordinates – Calculate and Convert a Position, go to Degree > Radian > Done > CP.

Press ‘ENTER’ to proceed.


synscan screen time zone


Next up is Time Zone. This is the same regardless of daylight saving months, so:

  • Los Angeles is -08:00
  • Toronto is -05:00     
  • Greenwich Mean Time is 00:00 (the + or – is of no consequence for GMT), 
  • Central Europe is +01:00.

Press ‘ENTER’ to proceed.



synscan screen date


The next screen asks for the date and provides us with our next trap! Some handsets tell you the format it requests but, in all instances, you should enter it in the format MM/DD/YYYY. If you use the International standard or UK/Aus formats, again, your mount will not be able to acquire a star alignment. 

Press ‘ENTER’ to proceed.


synscan screen time


The time screen that follows is a request for the time. Enter this in the 24 hour clock format.

Press ‘ENTER’ to proceed.


synscan screen daylight saving


You will now be asked whether or not you are in Daylight Savings Time. This is often also called Summer Time. Usually the months between March and October (ie when the clocks ‘go forward’) fall within Daylight Saving Time and the winter months do not.

Enter a ‘YES’ or ‘NO’ accordingly and press ‘ENTER’ to proceed. 


synscan screen polar alignment


The next screen provides some technical information that can assist you with a polar alignment if you understand the information.The HA figure is the ‘Hour Angle’ or how many hours have elapsed since Polaris transited (or reached maximum elevation in the sky – which will appear inverted to the 6 o’clock position in your polarscope).The Clock figure is where Polaris should appear in relation to the polarscope’s reticule. If it says 10:06 you can move the Right Ascension axis until the polarscope’s little circle is approximately in the 10 o’clock position to get a rough (but adequate) polar alignment.If you’ve followed my polar alignment tutorial, you can either check you have a good polar alignment or ignore this screen and press ‘ENTER’ to proceed. You will want your scope in the Home/Park position (scope pointing to Polaris) with the RA & Dec clutches tightened for the next steps: 

synscan screen begin alignment


Choose 1 to begin the fun stuff – a star alignment - and it will ask you for an initial star to align with. The best stars to us are ones that are around 45º high in the sky (half way from horizon to zenith) and at least 45º apart horizontally. You can choose a 1, 2 or 3 star alignment but 2 is usually good enough for visual observing.


synscan screen first star

Choose a star from the available options and let it slew to that region of the sky. If it is much more than a hands width away from being in your findscope’s field of view, you have probably entered some of the earlier details wrong (even a bad polar alignment should get this 1st star within a few inches of the right place).  Use the arrow keys and finderscope to get the star into the eyepiece view (the lowest power eyepiece you have), centre it and then pop in a high magnification eyepiece and centre the star. If the mount moves too slowly when trying to centre, press ‘2’ and enter a number from 1 (slowest) – 9 (quickest), followed by ‘ENTER’ to alter the movement speed. The handset offers stars that are amongst the brighter ones on view, so you will know by it’s brightness which one you should be trying to lock on to.

synscan screen second star

When you have the star centred, press ‘ENTER’, select a second star and repeat this step.

If you’ve chosen a 3 star alignment, repeat this step a 3rd time. When you press ‘ENTER’ on your final alignment star you should get the message ‘Alignment Successful’. If you get ‘Alignment Failed’, run through the star alignment again – this happens most often on a 3 star alignment, so choosing a 2 star alignment while you’re still finding your way around might resolve this.

synscan screen alignment successfulWhen finished, press ‘8’ followed by ‘ENTER’ to open a sub menu of:Named Stars (Albireo, Almaach etc)Solar System (planets & moon)NCG Catalogue (7,840 deep sky objects)IC Catalogue (5,000+ deep sky objects to supplement to the NGC Catalogue)Messier Catalogue (Charles Messier’s deep Sky objects)Caldwell Catalogue (Sir Patrick Moore’s catalogue)SAO Catalogue (of star designations)Double Stars (binary stars)Variable Stars (that brighten and dim over time)