Tutorial :- Setting up a Raspberry Pi for Astro Imaging and Hardware Control

[wornish]

Make sure you go for the RPi 3B+ it has more memory.     The 3B only has 512MB whereas the 3B+ has 1024MB. makes a big difference in performance.

[Altocumulus]

9 minutes ago, wornish said:

Make sure you go for the RPi 3B+ it has more memory.     The 3B only has 512MB whereas the 3B+ has 1024MB. makes a big difference in performance.

Just checked. Marked as a wish for Father's Day......

[stash_old]

On 29/05/2019 at 18:52, wimvb said:

micro sd card (go for 32 GB right from the start)

Size as ever is not so important but the speed and quality of the SD card is (very important) - Use class 10 98m/sec cards made by Samsung or Sandisk(maybe others) - and make sure they are genuine !  The SD card is the "Achilles heel" of the RPI and together with the shares Ethernet/USB2 bus stops the RPI being the best (by far) cost effective SBC for Astro work.

BUT dont just look at running everything on the RPI and think about your kit - fast CCD/CMOS with USB3 interfaces are,IMHO, a wasted resource limited by the RPI.

But as shown by APT's release 3.70 "one horse" solutions is not longer the norm and things are  now changing fast and IMHO for the better - you can spread your Astro hardware over cost effective/practical computer set ups.  

Control of mounts,focusers,rotaters,filterwheel's etc are not going to tax an RPI but fast resource intensive hardware/software is - so Platesolving(for fast solving!),fast Image processing/stacking etc are ,IMO,a no no on a RPI.

So investigate Client/Server Indi or Ascom Alpaca/Rest to see if they will meet you requirements. So run Platesolving/Image processing/stacking on a fast PC/Mac etc and let the RPI do the rest.

Obviously if you are thinking of  "in the field" Astro then the RPI excels as a low cost/low clutter solution - so long as you except its limitations.

Else there are other SBC and even small PC's that out perform RPI's BUT they do come at a price.

Lastly don't forget the software support - Indi on the RPI using Ubuntu Mate 16.04 is very very good - as good as (perhaps better in some areas) than Ascom IMO.

So do you homework as you are obviously doing 🙂

[wimvb]

3 hours ago, stash_old said:

so Platesolving(for fast solving!),... are ,IMO,a no no on a RPI.

I let a friend use my RPi 3B when his windows laptop crashed. It has a 32 GB Sandisk class 10 card, which we filled with astrometry index files. A smaller sd card wouldn't have worked. But local platesolving was fast. First blind solve under 3 minutes, next solve under 1 minute, usually even under half a minute if I remember correctly. Considerably faster than the online solver. 

3 hours ago, stash_old said:

Else there are other SBC and even small PC's that out perform RPI's BUT they do come at a price.

Rock64 sbc's are about the same price as RPi, but with more ram memory, larger sd card capacity, as well as usb3 support (but no wifi or bluetooth). Windows based solutions otoh are an entirely different matter. The larger card capacity is a plus if you do short exposure AP. You can keep images locally rather than loading them over wifi to a remote location (eg INDI client). Running everything on a local sbc, means that you won't loose anything if the connection goes down.

Edited May 31, 2019 by wimvb

[wornish]

The RPi is limited in how many USB connections it can power without issues.  So, if you are going down the RPi route then be sure to get a powered USB hub as well if you plan on connecting multiple items on your mount.   Mount itself + Guide Cam + Main Cam, ++ the list builds, perhaps a focuser + filter wheel + dew heater controller.  

[stash_old]

2 hours ago, wimvb said:

Considerably faster than the online solver

Agreed but then I ,as others do,do blind platesolving in under 20 secs -  and near platesolving in under 10secs - just not on a RPI 🙂 

"It has a 32 GB Sandisk class 10 card, which we filled with astrometry index files. A smaller sd card wouldn't have worked" I only use what is required by my kit which happily loads on a 16gb SD card including Indi - but the files are 19gb ( Approx) if you load them all which isn't a good idea as it can slow any platesolving down - as most use the std Linux Astrometry API - unless something has changed lately 🙂 

At the price SD cards are (relatively cheap - even good ones) it doesn't matter !

A Rock64(2gb) is £60 inc vat (more adding Wifi) on average in the UK so nearly 2 times the cost but you are 100% correct they are much faster for image processing / CCD than RPI.

 

[StarDodger]

12 hours ago, wornish said:

Make sure you go for the RPi 3B+ it has more memory.     The 3B only has 512MB whereas the 3B+ has 1024MB. makes a big difference in performance.

The 3b and 3B+ actually have the same memory both have 1024mb, there are other differences between them but not the RAM.. one is a 1.2 processor the other is 1.4, also the + has gigabyte Ethernet and better WiFi...

Edited May 31, 2019 by StarDodger

[wimvb]

3 hours ago, stash_old said:

Agreed but then I ,as others do,do blind platesolving in under 20 secs -  and near platesolving in under 10secs - just not on a RPI 🙂

On a Rock64 a blind solve took 38 seconds just now and subsequent solve 21 seconds. That's fast enough for a 35 USD device (current price at the Pine64 store).

As you noted, the index files for my setup take up about 20 GB on the SD card (down to the recommendation of 10% of the field of view). 

[wornish]

10 hours ago, StarDodger said:

The 3b and 3B+ actually have the same memory both have 1024mb, there are other differences between them but not the RAM.. one is a 1.2 processor the other is 1.4, also the + has gigabyte Ethernet and better WiFi...

OOPS  you are right     I should have double checked.  .  Sorry for the wrong info.  It certainly is faster though.