AstroPi3 Part 1 - Raspberry Pi 3 as a autoguider computer
AstroPi3 Part 2 - Creating the Installation Image
AstroPi3 Part 3 - Installing Ubuntu Mate
AstroPi3 Part 4 - Installing AstroPI3
AstroPi3 Part 5 - PhD2 Configuration
AstroPi3 Part 6 - DSLR/Guide Camera Setup and Control
AstroPi3 Part 7 - Raspberry Control with Tablet/Cell
AstroPi3 Appendix A - Index of Possible Problems, Causes and Solutions

The last ingredient in the recipe is to be able to visualize what is going on in the raspberry.
To do this, we have the following options:

a) Purchase a small screen for raspberry

The issue with this option is that it increases the cost of our equipment, as well as the energy consumption, and it may be possible (but not much) to decrease the portability.

b) Control the raspberry remotely via Wifi, with a cell phone or a tablet.
This is a good solution because these mobile devices are almost universal and omnipresent in our time. And the difference of a dedicated screen for the raspberry, even if we acquire a tablet, it will provide us with more additional functionality than a simple screen. This is the option we will discuss next.

Setting the Raspberry's HotSpot

Note: This tutorial has been made for Android phones. However, it can be applied to IPhone phones without any problems.

1. The first thing we have to do is to configure the existing HotSpot networks, which were automatically created when we run AstroPi3. The HotSpot mode allows you to configure raspberri to allow other devices to connect to it; unlike the Client mode, in which raspberry connects to another existing Wifi network.

Click on the Wifi icon in the upper right hand corner of the screen, and then on the Edit Connections menu ...

3. The Wifi network configuration window will be displayed. Look for two already created networks, usually starting with the name you assigned to your raspberry when you installed Ubuntu Mate. One is for devices that connect to 2.4Ghz Wifi networks and the other one to 5 Ghz.
Select one of them and click on the Edit button

4. Click on the Wifi Security tab, delete the current password and type in a new one.
Tip: To avoid confusion and make it easier to remember, write down the same password you assigned to the user in the Ubuntu Mate installation stage.

5. Click on the General tab and then make sure the Automatically connect to this network when it is available box is checked/enabled. This will allow the rapsberry to activate this network when it is turned on; otherwise, we cannot access it via wifi when we are in the field (unless we have a keyboard, mouse, monitor... which is not very feasible and would contradict our goal of portability... ).

6. Click the Save button. Repeat the same steps for the other network in the list.

Important: If your computer cannot connect to both types of networks, I strongly recommend that you delete the network that it cannot connect to from the list, i.e. if your computer only accepts 2.4 Ghz networks, delete the 5 Ghz network from the list. This will ensure that when you are in the field, Raspberry connects to the right network.

HotSpot activation

It is necessary to connect the Wifi of the same raspberry to its same HotSpot network, otherwise your cell phone will not detect it.

7. Before you start, find out what type of networks your mobile device can connect to, as there are devices that can only connect to 2.4 Ghz networks, and others that are dual band, i.e. can connect to both types. If your cell phone, for example, can only connect to 2.4 Ghz networks, that's the network you'll select.

8. Click on the Wifi icon at the top right of the screen and click on the option Connect to Hidden Wi-Fi Network ...

9. Select the HotSpot network you just set up and then click the Connect button.

VNC app installation on our mobile device

Before connecting to the Raspberry HotSpot, we must prepare our cell phone/tablet with the application that will allow us to control it. This application is the VNC.

9. Open GooglePlay (Android) and install the VNC Viewer - Remote Desktop application

Remote control and raspberry connection

10. Open the list of Wifi connections. The network you have just configured should appear in the list; connect to it. Remember that the network password is the one we have just configured in the previous steps.

Note: If you do not see it in the list, there is a possibility that you have connected Raspberry to the wrong network, i.e. your phone may only support 2.4 Ghz networks and not 5ghz, and you have activated the latter.

11. Now open the VNC application you just installed and click on the green "+" icon in the lower right corner.

12. It will ask you for the following information:
a) The IP address of the machine to which to connect.
This address is usually, which is the default.
Anyway it's easy to know which is the address by double clicking on the VNC icon at the top right of the Ubuntu Mate screen
b) A descriptive name for the connection: enter any name you like.

Press the Create button

13. You will then be shown the connection screen. Press the CONNECT button

14. It will ask for your username and password, which are the ones you indicated when installing Ubuntu and which are automatically authenticated every time you start the raspberry. This is not the Wifi password (which is a separate password entirely)

15. That' s it! You will be able to see on your mobile the screen of the Ubuntu Mate.

Here are some tips:
a) To control the mouse, simply drag it on your cell phone screen. One tap to click, two taps to double click.

b) When you need to write, tap on the text field. Then drag your finger from the top of the screen down to show the VNC pop-up menu. Then click on the keyboard icon.

c) To close the connection, display the pop-up menu again and click on the " X " on the right side.

Fire test of your device

16. Turn off your raspberry and disconnect the TV/monitor, keyboard and mouse. Turn it back on and wait a few seconds ( do not connect monitor/tv, keyboard or mouse ).
Then try to access via your mobile device, following the steps described above.

Congratulations !!!

You have finished the tutorial, now you will be able to control your guiding equipment with this light and low energy consumption device.

As an extra, I have made an appendix with a list of possible problems and solutions that I found during the installation process.