Guide Camera Choice: Help Needed (Not Another QHY VS ZWO Thread)

[endless-sky]

Hello,

I have been successfully using KStars/EKOS on a Raspberry Pi 4 - 4GB RAM to control my current equipment for quite some time.

I currently use Astroberry installed on a SD card and everything is connected to the Pi (I use a very old laptop running Lubuntu to remotely access the Pi with VNC Viewer, since the laptop itself is uncapable of running anything...).

Before jumping to Linux, I managed to make some astrophotography software work under Windows XP with the laptop, but I could never get it to control the camera. Rather than buying a whole new laptop, I decided to give the Rapsberry Pi a try and I have to say I am very satisfied with the performance. The only thing I miss is the fact that with EQMod under Windows I could use PEC, and KStars/EKOS only support it for Permanent PEC capable mounts...

Currently my setup is as follows:

Mount: Sky-Watcher NEQ6 Pro
Imaging camera: Nikon D5300 Astromodified
Joystick for fine tuning the framing
Astrometry for plate solving

So far I only used some Nikon lenses that I already owned from my every day photography (70-300mm, 50mm) for my astro-imaging, but I am in the process of acquiring some new gear:

Telescope: Tecnosky Triplet Apo SLD FPL-53 80mm f/6 V2 with 0.8x flattener/reducer

Guide scope: Tecnosky SharpGuide 60mm f/4

Guide camera: ?

I am pretty sure about the choices of telescope and guide scope (unless anyone has any advice to give on that same price range: the telescope plus reducer is under 1000 Euro, which seems to me as an awesome deal), but I would like some advice on the guide camera.

As I wrote on the title, the purpose of this thread is not deciding which camera is best between QHY and ZWO (as far as I understood, they are basically the same, if we consider the entry level guide cameras).

The purpose of this thread is deciding which one to buy with the following considerations in mind:

1) I would like for the camera to work with my current setup, under KStars/EKOS, with pulse-guiding (as far as I know it's better than ST4), connecting it to the Raspberry Pi 4 (if I need to purchase a powered USB Hub, it's ok - so far all the equipment that is attached to the Pi has its own power supply)

2) I would also like for the camera to work both with EKOS internal guiding and PHD2 as an external guider for EKOS, just to have the option of testing which method gives me the best results

3) It has to be relatively cheap

4) I would like for the camera to be "future proof": I also own a very old Celestron C8 (it's been with me since 1997), so once I manage to get the "easier" setup working (80mm imaging scope + 60mm guide scope), I would love if the camera could work also in an OAG setup with the C8 (so I would just need to buy an off-axis guider and possibly a reducer, instead of buying yet another guide camera)

5) Last, but not least, I would like if the camera could work also if one day I decided to upgrade from the DSLR to a dedicated astro-camera (I read on the INDI Forum of a lot of people having troubles running two same brands cameras at the same time, one for guiding and one for imaging)

So far my choices of guide cameras are:
-QHYCCD QHY5L-II-M
-ZWO ASI 120MM Mini (Mono)

Any other suggestions, in the same price range of the above mentioned, are welcome!

Also, for the refractor/guide scope setup I mentioned, would the color versions of those cameras be sufficient for guiding, so they could also serve as planetary imaging cameras? With an f/4 guide scope I shouldn't have any problem finding guide stars, correct? But probably they would not be good enough for the OAG and the C8...

I have read a lot of posts in this forum concerning the two cameras of choice and I have read of many people having troubles with both (expecially with drivers, even under Windows...).

I have also read of a lot of people having troubles with some versions of the 120MM (the Mini or the -S, I am not really sure) and Linux/Raspberry.

I don't know if the problems have since been solved, with the latest versions of KStars/EKOS, so any help is appreciated, expecially from people that have a working Raspberry setup with those cameras.

Since, as we all know, astrophotography is an expensive hobby/passion, I would like to make the right choice and be sure that the camera I will buy will be fully compatible with the hardware/software I am using.

I am sorry if these questions have been asked before, but as I said, I would like to buy something and not have any bad surprises along the way!

Thank you all for your help and clear skies!
Matteo

(Edit: typos...)

Edited May 24, 2020 by endlessky

[alacant]

We use the 120mm and its -much cheaper- clone, the t7m, in oags on all telescopes up to 1200 mm focal length without problems. 

Both work fine under Linux using EKOS or PHD2 guiding. If the latter, I'd recommend the native PHD2 zwo driver.

Never used qhy with guiding so can't tell if it's any better.

Cheers and HTH

Edited May 24, 2020 by alacant

[endless-sky]

Thank you for your reply. Could you please specify which model your 120mm is? Is it the Mini or the -S variant?

Clear skies,

Matteo

[teoria_del_big_bang]

16 hours ago, endlessky said:

I have also read of a lot of people having troubles with some versions of the 120MM (the Mini or the -S, I am not really sure) and Linux/Raspberry.

Hi Matteo,

Sorry I cannot help you with your question  as I do not have the experience but your comment here is of great interest to me as I already have a ZWO main ccd camera and also trying to change my setup to use Astroberry / KStars on a RPi 4B and also was just about to order another ZWO camera for guiding. Can you direct me to any of the threads or other forums discussing this issue. 

Many thanks if you can

Steve

[endless-sky]

Hi Steve,

if I can, I will help you gladly! Nice to hear that you are getting a setup similar to mine, at least in the hardware/software point of view. Going purely from Windows, it was kind of a very steep learning curve, for me, as I did not have much prior experience with Linux, but at the end of the day it's not really impossible, after you learn those three or four commands necessary to keep the system up to date (in the case of Astroberry, is Raspbian based, so you'll use the typical "sudo apt-get update" followed by "sudo apt-get upgrade", and that will do all the work for you). Astroberry is really awesome, too, as you don't have to build your installation from scratch, you just burn the image on an SD card, plug it in the Pi, power it up and it's ready to go. You won't even need to use a keyboard/mouse/screen with it, as it boots up and starts the hotspot by default. You just need to instal VNC Viewer on the PC/laptop and connect to the Pi using the default hotspot IP address provided by the author of Astroberry on his site. KStars/EKOS require some configuring/tuning: I strongly advice you to use the Simulator profile, first, to have an idea of what every single module does. And do everything indoor, a few times, before trying it on the field for the first time. Clear skies are a rare event as it is - as we all know - and you don't really want a clear night to turn into a configuring nightmare... 🤣

But we are going off topic... If you need help with Astroberry, let me know, I will gladly tell you all I know!

As far as comments on the various versions of the 120MM, I found mostly topics about them on the INDI Forums. It seems the 120MM Mini only works in 8bit mode, with EKOS and it seems it has to do with the size of the packets going from the camera to the Pi that Linux Kernel is not able to handle, because it expects a different size of packet. It also seems that the 120MM-S does not have this problem, because it has a USB 3.0 port and that seems to work fine. It just is unfortunate that the form factor of the 120MM-S is a lot bigger and most likely will not allow it to be used on a OAG...

Also, you say that you already have a ZWO as a main camera. Another problem that you may encounter under EKOS is that using two cameras of the same brand at the same time might cause issues... That's another thing I read on the INDI Forum. Apparently there are workarounds, as connecting one first, then the other, and making sure the correct model is listed under the Imaging Module and the Guiding Module of EKOS. Other poeple report no issues at all, so I don't really know what it depends on... I know these informations might throw you off from even wanting to try Raspberry+KStars/EKOS, but once you solve the issues, it's really worth it. I found it very nice to have "everything under one roof". Using the same suite I can control the mount movements with the planetarium (KStars), focus, platesolve, plan the capturing sequences and - soon - guide. The developing team is very active and they are constantly adding new features / solving issues. The Pi is also really small and fits perfectly on the dovetail. Really a nice package!

I don't know if I am allowed to provide links to other forums in here, so I'll probably send them to you in a private message?

Off topic: your user name is in Italian, are you Italian too, by any chance?

Clear skies,

Matteo

Edit: typos...

Edited May 25, 2020 by endlessky

[teoria_del_big_bang]

Hi Matteo,

No not Italian, but have worked there many times and love the country.

I actually thought it was Spanish (which it may well be as well I guess). Again not Spanish either but lived close to Valencia for around 18 months again working and my first Son was born there as well so I have a great love of Spain as well.

Born and bred in Yorkshire UK.  A lovely part of the British Isles but not too great for astrophotography due to weather 😞 

Many thanks for the time you have taken to answer my question I am most grateful and will look through all the links on your PM.

I also feel it is a steep learning curve for me moving from APT (which is wonderful software and really like it) but like you say the ability to have all the software on the mount in a very lightweight computer that only cost around 50 Euros is just unbelievable. I tried for a long while running all the software indoors with cables going to mount but USB cables over around 3M just ask for trouble so I think the only sound solution is to have the computer at the mount then remote desktop somehow to is wirelessly. Then once the sequence has started if the ling drops out for a while the computer carries on regardless and nothing is lost. So for past 18 months I have had a rather expensive fanless windows pc on the mount running APT, Stellarium, PHD2 etc and to be honest it works great. But I want to try Ekos / KStars as so many use it it must be good and if I can sell the expensive windows I7 rather bigger PC on and do the same with a cheap very light RPi then that is a bonus. Also incidentally I have also managed with same setu to still use APT to connect to the INDI server and so can actually revert to how I used to run without changing anything at the mount. APT is still in its early days with INDI but I am sure this will be greatly improved in future releases. So if I get it to work will have many options with this setup.

But I was about to push the buy button on a ZWO ASI120MM-Mini  for guiding. I currently use a Altair Astro GP-130M mono which worked fine for my previous setup. I have actually now just got it working with Ekos but it took some doing and is a bit flakey, maybe my doing not sure.

Anyway sorry to keep rambling on and hijacking your thread, I may well take you up with help on Astroberry in future if that's okay  🙂

Good luck with your purchases anyway and hope all goes well

Stay safe

Thanks

Steve

 

 

Edited May 25, 2020 by teoria_del_big_bang

[alacant]

2 hours ago, endlessky said:

which model your 120mm is? Is it the Mini or the -S variant?

Clear skies,

Hi

We have both. Both work fine. EKOS/Kstars/phd2 under Ubuntu 18.04.

HTH

[endless-sky]

Glad I could be of help, Steve!

And thanks again alacant, that gives me hope that both cameras are of equal choice, as they both work. I will be doing some more research, as I have to wait some more time before buying the whole setup, anyway.

Thanks again!

Clear skies,

Matteo