Introduction | Instructions for the 2-Star Alignment When Using the Handbox | Instructions for the Alignment When Using the SynScan Module and the SynScan App | Tips from the Manuals and My Experience | Instructions for the Celestron StarSense AutoAlign for Sky-Watcher Module | Conclusions | Links
On this page I compile instructions for the operation of the Sky-Watcher
Star Discovery mount** using the handbox and
the SynScan Wi-Fi
module and also provide some useful
tips from the manual. I conclude this page with instructions for using
the mount with the Celestron StarSense AutoAlign for
*) The mount has the long name Sky-Watcher Star Discovery AZ GoTo telescope mount, so it is an azimuthal mount and in my possession since July 2016.
*) These Instructions are also valid for my Sky-Watcher AZ-GT mount as long as it is used in the AZ mode.
Mount from one side
Mount turned around
Ditto with external power supply (Sky-Watcher Power Tank 12 V / 7 Ah)
In the following, I attempt to describe in simple words the most important alignment procedures that can be performed when using the Star Discovery mount, either with the handbox, with the SynScan Wi-Fi module and SynScan app, or with the Celestron StarSense module including its own hand control. I hope that reading these instructions will be faster than reading the manual. Some steps are omitted (often further pressing of the ENTER key).
I also pass on some hints from the manuals and from my experience.
The following table is an attempt to provide an overview of the different possibilities:
|Mode||Name||Mount Position before Power on||Procedure after Power on||Typical Accuracy||# of Alignment Stars||First Action (after Power on)|
|Handbox||Tracking||Tracking||In home position||Nothing||Tracking OK?||--||You manually point to sky objects|
|Alignment||2-Star Alignment||Home position not critical, but is helpful (I assume)||Perform alignment||GOTO and AZ tracking: Good||2||Handbox starts rough GOTO to the first star|
|Synscan Wi-Fi||Default Pointing Model||Tracking, rough GoTo||In home position||Nothing||GOTO and AZ tracking: Satisfactory||--||You manually point to sky objects|
|Non-Default Pointing Model||1-Star-Alignment||Home position not critical, but is helpful||Perform alignment||GOTO and AZ tracking: Good||1||App starts rough GOTO to the first star|
|Brightest Star Alignment||2||You manually point to first the star|
|North-Level Alignment||2||You manually point the telescope level and to north|
|3-Star Alignment||3||App starts rough GOTO to the first star|
|Celestron StarSense with Hand Control||Tracking||Quick Align||In home position||Nothing||Tracking OK?||--||You manually point to sky objects|
|Alignment||Plate-Solving||Telescope tube level||Perform automatic alignment (and calibration if needed)||GOTO and AZ tracking: Good||1 (for calibration)||Nothing|
Home position: Telescope tube level and pointing to true north.
Note: I do not cover the Brightest Star Alignment method here.
Note: The alignment can also performed later (key "MENU" > "Setup" > "Alignment" > "2-Star Align.").
*) The speed can be adjusted manually to one's own needs (Press key "RATE"
and a number key, then further number keys if needed)
**) This procedure should always end with using the UP and RIGHT keys (to minimize mechanical backlash); if you overshot, use the opposite key to return and then use the recommended one.
Press key "MENU", select item "Alignment" in the "Setup" menu using the scroll keys, and then the 2-star-alignment; continue as described for the 2-star-alignment.
You can also switch the mount off and then on again. Level the telescope and point it north before switching it on, particularly if you want to use tracking only.
Note: On this page, I only cover alignment methods for alt-azimuth mounts; therefore, the 2-star alignment is missing here, which is only available for parallactic mounts since an update of the SynScan app.
Box content (and glasses...)
The adapter module
Ditto, connected to the mount
(1) Connect and start the app:
(2) Power the mount on:
That is, the mount is to be set to the "home position" before powering it on. The data for the observation (location, date, time etc.) is taken from the smartphone; if in doubt, check the location data in menu "Settings".
(3) Start the alignment: Go to the "Alignment" overview screen and select one of the alignment methods offered there to start the alignment. In the following, these are described in short form.
First action: The app starts a rough GOTO to the first star (from manual)
*) This only works if the mount was previously in the "home position" (mount and tube horizontal, tube aligned to the north), but you can move the telescope to the correct position (as with Brightest Star Alignment).
First action: Manually point the telescope level and to north (from manual).
First action: Manually point to first star (from manual).
First action: The app starts a rough GOTO to first star (from manual)
Sky-Watcher notes that is is important to put the alignment stars at the center (or the same spot) in the field of view of the telescope's eyepiece and thus, recommends to either use
Actually, my crosshair eyepiece (see above) also has a shorter focal length (12.5 mm), which makes it difficult for me to come up with a good alignment at telescopes with longer focal lengths, because the alignment stars move so fast. I therefore prefer to use eyepieces with longer focal lengths for the alignment process.
Update: In January 2020, I purchased an additional crosshair eyepiece with a focal length of 23 mm, which is better suited to tubes with a longer focal length, such as my Celestron C8.
Sky-Watcher also suggest to defocus the telescope, because the larger, defocused star shape (a disk...) is easier to center than a sharp star.
Since all mounts have more or less mechanical backslash on both axes, Sky-Watcher recommends the following:
The Star Discovery mount has an "easy tracking mode" for doing just this. The steps to enable this mode are as follows:
Now you can directly point the scope to the desired target using the handbox, and the mount will track the target automatically. If you want to track the moon or the sun, you have to set the respective tracking speed in the "Tracking" menu (otherwise the sidereal rate is being used). For observing terrestrial targets, you can also stop tracking in the "Tracking" menu.
When no alignment has been done, the SynScan app uses the "default pointing model" (location related), which allows a roughly accurate GoTo and tracking. The accuracy of the "default pointing model" depends on how perfectly the mount was placed in the home position before power on. The following table from the manual describes the differences:
|Mount position before power on||Procedure after power on||Typical accuracy|
|Default pointing model||In home position*||Nothing||GOTO and AZ tracking: Satisfactory|
|Alignment (non-default pointing model)||Home position not critical, but is helpful||Perform alignment||GOTO and AZ tracking: Good|
*) Home position:
If you take a look at the Sky-Watcher and Celestron handboxes, they look very similar at first sight (I own a Celestron StarSense handbox as well):
Photo: Sky-Watcher SynScan handbox (left) and Celestron StarSense handbox (right)
At a closer look, however, you will notice striking differences! The same functions are named differently and/or are located in different positions, especially the general "navigation functions", which one can master "blindly" after some practice:
|Sub menu /Start an action||ENTER||ENTER||left/center||If you as a Celestron user want to press "ENTER", you end up in the setup menu (key "MENU"), this is "confusing"!|
|Back/Cancel||ESC||BACK||left/right||If one knows the "BACK" function, probably does not understand what "ESC" does (the same)...|
|Setup menu (includes the alignment)/Alignment||MENU||ALIGN||center/left||Similar, but not identical; the text "MENU" suggests to me something quite different from what the key actually does, namely a jump to the top-level menu.|
What do these differences mean in practice? Unfortunately a lot! If, for example, your hand grips come "blindly" for the Celestron handbox, you will keep coming back to the "MENU" key on the SynScan handbox, when you actually wanted to press the "ENTER" key - because it is located in the middle of the Celestron hand box.
So you will end up in the "Setup" menu, actually at the first item date entry. In the opposite case, you will get back instead of forward...
The "MENU" key leads to the "Setup" menu despite of its label. In my eyes, this labeling is simply misleading. I had expected that this key would lead to the top level of the menu system. I needed to consult the "thick" manual (needs to be downloaded from the Internet....) and find the page describing the shortcut keys to find out what this key actually is meant to do...
Note: On this page, I only cover alignment methods for alt-azimuth mounts.
The Celestron StarSense AutoAlign for Sky-Watcher module contains an additional interface box, which is best attached to a tripod leg. For the cabling the cable of the SynScan handbox is required. Below, I describe how to make the connections!
If you want to use the StarSense AutoAlign module for the first time, the module must first "learn" how the StarSense camera and telescope tube are aligned. This requires a calibration. Before the calibration, an AutoAlign has to be be performed, as well as after calibration, before you can begin observing.
StarSense interface box and handbox on mount
Photos: StarSense on Explorer 150PDS and Star Discovery AZ GoTo mount
Initially, I found a lot of contradictory and wrong information as to the calibration procedure. I have therefore developed a "personal" procedure for my purposes, which consists of the steps described in the following. This has, however, been confirmed by videos and Michael Swanson's book (I also found a "fast lane" to the calibration that nobody seems to know...).
"My" calibration procedure is different from that in the manuals (but similar to Celestron's video, other videos, and Michael Swanson's book) and as follows:
*) Alternatively, as shown in some videos (e.g. this
one) and written in Michael Swanson's book, you can press "BACK" twice,
then press the "MENU" key, where you will find the (undocumented) "StarSense" menu
with item "Calibrate" in first place; press "ENTER" again
to get to the calibration procedure.
**) Use the keys "UP" and "RIGHT" as last keys (after that, a small check mark appears in the upper right corner of the display; this procedure avoids gear backlash of the mount).
Note: According to the "latest" manuals, the StarSense module no longer needs to be switched off and on again, and the telescope tube no longer needs to be aligned horizontally before pressing the "ALIGN" key and selecting "Auto Align" for a second time.
The next time, a simple "Auto Align" should be enough to get started. But always check the date and time first (menu "Time and Location") first:
With the function "QuickAlign" it is possible to track without having to perform a complete alignment. The telescope uses its home position (tube level and pointing to the north) as the only reference point for calculating where the objects should be in the sky (based on the time and location inputs).
These instructions were meant to be simple, but it turned out that they became more complex than expected. Nevertheless, they helped me to find out the differences between the various alignment methods for the SynScan Wi-Fi module and also made clearer to me how to use the handbox. They furthermore helped me to clarify the usage of the Celestron StarSense module.