A journey into the Raspberry Pi world

[JSeaman]

I have been involved in astrophotography for about ten years and I wish I had done this years ago so thought I would share my experience. I have literally only spent a couple of hours on it and feel like I’m as comfortable with it as any other software I spent months learning. There are lots of ways of achieving the same thing with this architecture but I found the following very easy and hope it helps kick start someone else into the Pi world, it’s really quite impressive!

I have a fixed observatory and always struggled with connectivity; I tried passive/active USB cables, Startech hubs, USB over Ethernet and probably other things I have forgotten. Some of them worked for a few months, some a year or two but nothing was truly reliable. I had also used various software tools from intervalometers to APT to PHD to Nebulosity to Cartes Du Ciel (CDC) etc. and they all had their quirks and issues too, essentially setting up was always a bit of a worry. Don’t get me wrong, most nights were perfect but then every now and then it would be a catastrophe.

I bit the bullet last week and decided I needed a Raspberry Pi in my life (it was a toss up between the more expensive ASIAir/NUC or the dramatically cheaper Pi and I took that option with zero regrets!). My concerns were around having to re-learn Linux stuff and all the software I had gotten to know as well as driver battles and lack of support. All these preconceptions were unfounded.

I bought the raspberry Pi and charger from https://thepihut.com/ which was £65 delivered next day for a Pi4 with 4GB RAM (which is plenty). I also got a metal case with heatsink and fan for £13 (here), a micro HDMI to HDMI cable for a couple of quid and a 64GB Class 10 SanDisk card for £10 off Amazon. So £90 and there is a complete PC at your disposal, a bargain!

The installation took literally a few minutes, I simply downloaded Astroberry which is free (here) which is the complete OS and software tools in one package. I flashed it onto a micro USB card using Balena Etcher (here) from my PC then plugged it into the Pi and up it booted. I was greeted with a Windows-esque GUI and ran one piece of software called KStars which allows me to do everything.

Note that you can do EVERYTHING remotely on the pi, on your desktop PC you just navigate to http://astroberry.local/desktop/ in your browser and you have a remote desktop style VNC connection and can work from there fully (password is astroberry when you press connect). I changed the password for the system and VNC but that is optional I guess. Just plug an Ethernet cable in and you are away, it can be done using wifi but the range is a bit limiting and I wanted something truly robust this time.

It looks like CDC or other planetarium software so you can look around, zoom in and out and select targets. It will ask for your location and allow you to download a few different catalogues which I did.

[JSeaman]

Then you enter the world of Ekos which allows you to bring in all your hardware, simply click the button shown below (of click tools then Ekos or press CTRL+K):

 

Just like KStars there are a couple of set up steps, first a general intro (hit next)

 

Then go for Equipment attached to the device (unless you run it as a remote server, I know some people had latency issues so I ran on the pi outside mounted on the scope)

 

It finds all your stuff and all worked seamlessly for me. From here on in, you just click the play button to connect everything

 

Ekos uses the INDI which is described in detail here, it is a pretty neat approach and works well

 

You can download the source code for both Kstars and Indi which is pretty nice, both open source projects on github.

[JSeaman]

I’m still finding my way around but I have done the following so far:

 

Set up a Profile

 

You can add different profiles for different kit configurations easily from the Ekos window

 

 

I only have one profile which is where I list all my gear. I selected the following for my ASI ZWO 120mm guide scope, ASI ZWO 1600mm camera, NEQ6 Pro Mount and Lakeside Focuser (note I chose for it to autoconnect and guide using KStars directly which is way easier than PHD to set up initially!)

 

 

[JSeaman]

Indi Control Panel

Once you have a profile set up, click the play button mentioned above and the control panel will appear with all your stuff:

 

You can delve into all the menus and find dozens of settings you never knew about. The interface is such that the bold white text on a button is the selected state e.g. above, the connection is live and you can click the button marked “Disconnect” to drop it

[JSeaman]

Custom Home Position

Like most astro mount controller software, it expects the mount to be at 0/0 for RA/Dec on power up. I use a custom park position so started up in the traditional “Home” position of 0/0 and then moved the mount as follows:

Click on the mount icon

 

On the right hand side you will see the mount control button:

 

If you are familiar with EQMod then this is a similar interface, if you’re not it’s fairly self explanatory, press the buttons and move the mount around. You will need to unpark it first and you might want to drag the slider to the right so you can slew around quickly

Once you have found your new home position, pop back to the Indi panel and choose Site Management then press the Set button shown below

 

[JSeaman]

Picture Sequence

Similar to APT and other tools, you can set up a sequence of photos to take using different settings, filters etc. Click the camera button and choose the right CCD from the list highlighted below. Then enter any settings e.g. 50 pictures of 600 seconds then press “+” to add it to the sequence

Save the sequence using the button on the right

[JSeaman]

Schedule

There is also an over-arching scheduler which lets you control the whole astro session. This handles everything from unparking the scope through to shutting things down and you also call a Sequence as set up previously for taking the images

 

You will notice there are 4 Steps shown on the top left which are:

 

1.       Track – goes to the target which you select using the “Target” box

2.       Focus – will automatically focus on a star for you

3.       Align – Plate solves and moves to accommodate any positional errors

4.       Guide – Guess what that does?!

 

This is all so easy and works really well

[JSeaman]

Shutdown Script

I wanted to turn the Pi off automatically at the end of my session, to do this you can run a script. You can do this a number of ways but my approach was to right click on the desktop and choose new file:

Type in a name ending with .sh (Unix SHell file extension for bash scripts), I called mine Shutdown.sh

 

 

Enter 3 lines:

#!/bin/bash
shutdown now
exit 0

The first line tells the interpreter it is a bash script, the second one switches off the pi without a password prompt and the third line just returns a success code for running the script.

The last thing to do is right click on the file and choose properties then  give execute permissions to anyone

 

 

Your shutdown procedure shown in the previous section can then just point at this script to fully switch things off and look after that SD card before you pull power

Edited June 21, 2021 by JSeaman

[JSeaman]

Focusing

 This was a really pleasant surprise after having to go in and out with a Bahtinov mask for the last couple of years, Ekos will control your guide CCD (ZWO ASI 120mm mini for me) and your focuser (Lakeside in my case) to achieve focus. You can manually move things around or set the position but just hit auto focus without setting anything up and it achieves perfect focus (verified with my trusty Bahtinov afterwards)

[JSeaman]

Guiding

This worried me the most, I have lost more time than I care to think tweaking PHD, changing parameters, playing with different algorithms, calibrating for minutes at a time etc. With this, I ticked autostar and pressed guide, within seconds it was guiding. Absolutely amazed by how well this all hangs together

[JSeaman]

OK so that's it, it went from being a "yay it works" thread to more of a how to but hope it helps, I'm pretty pleased with everything currently, hopefully I'll feel the same with a few years of astro work under my belt!

 

[fozzybear]

Congrats on getting all to work. It is a nifty bit of kit once sorted. And Kudos to @RadekK as well for putting it all together. 

[Stuart1971]

2 hours ago, JSeaman said:

Custom Home Position

Like most astro mount controller software, it expects the mount to be at 0/0 for RA/Dec on power up. I use a custom park position so started up in the traditional “Home” position of 0/0 and then moved the mount as follows:

Click on the mount icon

 

On the right hand side you will see the mount control button:

 

If you are familiar with EQMod then this is a similar interface, if you’re not it’s fairly self explanatory, press the buttons and move the mount around. You will need to unpark it first and you might want to drag the slider to the right so you can slew around quickly

Once you have found your new home position, pop back to the Indi panel and choose Site Management then press the Set button shown below

 

Just a quick FYI on this section, rather then click set, you should click “write data” as this puts it into the long term memory, whereas set just seems to set for that session, and it can be lost on reboot….and then your should save the config on the options tab, as with all INdI drivers…👍🏼

Edited June 21, 2021 by Stuart1971

[JSeaman]

That's interesting, the data certainly persisted on my set up (I checked with the roof off before trying again!!) but thanks anyway

[Stuart1971]

2 minutes ago, JSeaman said:

That's interesting, the data certainly persisted on my set up (I checked with the roof off before trying again!!) but thanks anyway

Yes it may well do, and then one day it won’t, always best to use “write data” or you may well come unstuck…this is why this setting is there…..
you can also slew the mount in Kstars to a position, then right click, choose “mount” and then choose “set as park position” this works too, but whichever way we do it I always go back to the driver and “write data” then save, just to be sure….👍🏼

[Stuart1971]

One useful tool that’s just been implemented, is to be able to take a 360 degree image of your own garden view, and import into Kstars planetarium, so you can see what is in view and what is hidden behind trees, or building etc, very easy to do, I use an old iPhone with the google street view app, which allows you to take a 360 degree sphere photo and export it, then in PS, or Affinity which I use, or any other editing software, remove the sky and save as a PNG file, then open it in the Kstars software, one tip, when you start the photo, make sure you are pointing the camera close to North, as it will automatically place the centre of the first image on north, but there is an azimuth adjustment in Kstars if you are a bit off….

Here is mine looking almost south from inside my Astro shed…

 

[Avocette]

Hot news from @RadekK - he has just updated the repository:

“New version of KStars and INDI in da House! 🥳🥰⭐️🚀

Updated core components: 
- KStars 3.5.3
- INDI 1.9.0
- PHD 2.5.9 (dev5)
- Oacapture 1.8.0
- all INDI drivers and libraries.

Upgrade and enjoy!”

[Stuart1971]

11 minutes ago, Avocette said:

Hot news from @RadekK - he has just updated the repository:

“New version of KStars and INDI in da House! 🥳🥰⭐️🚀

Updated core components: 
- KStars 3.5.3
- INDI 1.9.0
- PHD 2.5.9 (dev5)
- Oacapture 1.8.0
- all INDI drivers and libraries.

Upgrade and enjoy!”

Great….

I only asked him yesterday, and he said it would be this week sometime…..👍🏼

[fozzybear]

29 minutes ago, Avocette said:

Hot news from @RadekK - he has just updated the repository:

“New version of KStars and INDI in da House! 🥳🥰⭐️🚀

Updated core components: 
- KStars 3.5.3
- INDI 1.9.0
- PHD 2.5.9 (dev5)
- Oacapture 1.8.0
- all INDI drivers and libraries.

Upgrade and enjoy!”

PHD 2.6.9 (dev5)

Oacapture 1.9.0

one mine after the upgrade just done it 

cheers for the update

[BCN_Sean]

2 hours ago, Avocette said:

Hot news from @RadekK - he has just updated the repository:

“New version of KStars and INDI in da House! 🥳🥰⭐️🚀

Updated core components: 
- KStars 3.5.3
- INDI 1.9.0
- PHD 2.5.9 (dev5)
- Oacapture 1.8.0
- all INDI drivers and libraries.

Upgrade and enjoy!”

Just said a few choice words, as spent the day off yesterday building the whole lot from source!

[Stuart1971]

9 hours ago, BCN_Sean said:

Just said a few choice words, as spent the day off yesterday building the whole lot from source!

That’s a shame…

Its not such a bad thing that Astroberry is not updated as soon as a new Kstars, INdI and so on version comes out, as they are always buggy and it gives time for them to be sorted, so when we do get the update, it should be a bug free upgrade and no messed up sessions….it suits me personally being a bit behind….👍🏼

[JSeaman]

I had my first go at running a full schedule last night, I managed to unpark, slew, focus, plate solve, guide, image and shutdown perfectly. The second time I did it, the mount didn't park properly but everything else worked. I'll need to re-set the home position and I have enabled verbose logging to file and just downloading the latest updates to see if I can reproduce it

Edited June 23, 2021 by JSeaman

[BCN_Sean]

53 minutes ago, Stuart1971 said:

That’s a shame…

No, not much of one; I'm on a bug hunt at the moment.  I was noticing some odd behaviour in a couple of the 1.9.0 indi-3rdparty drivers/3.5.3, like west slewing in the eqmod not responding and sidereal tracking kicking in when using the drift align, and also a couple of others not releasing and resetting when Indi is restarted after Ekos crashed; and then also under certain conditions the internal solver causing a memory segmentation error.

Having two different builds does make it a bit easier to decide if it's something in the builds themselves or something underlying on the system if it only occurs on one install or both.

[wimvb]

3 hours ago, Stuart1971 said:

That’s a shame…

Its not such a bad thing that Astroberry is not updated as soon as a new Kstars, INdI and so on version comes out, as they are always buggy and it gives time for them to be sorted, so when we do get the update, it should be a bug free upgrade and no messed up sessions….it suits me personally being a bit behind….👍🏼

I don't use astroberry as my sbc is a Rock64, but I learned to never upgrade during astro season. When I started using INDI/Kstars, new upgrades could be so buggy that I would lose several precious imaging nights. Hence my policy to upgrade only during summer recess. Nowadays I have several sbc's and only upgrade one at a time. That way, if something breaks during an upgrade, I can just swap computer and keep on imaging. It's better to have an older version that works, than the newest gadgets that don't.

[Stuart1971]

4 hours ago, JSeaman said:

I had my first go at running a full schedule last night, I managed to unpark, slew, focus, plate solve, guide, image and shutdown perfectly. The second time I did it, the mount didn't park properly but everything else worked. I'll need to re-set the home position and I have enabled verbose logging to file and just downloading the latest updates to see if I can reproduce it

Write data, will sort home position out….👍🏼