Monday, July 24, 2017

How to solar charge Li-Ion batteries

So, I bought two Li-Ion batteries for the field. They are definitively smaller and much lighter. I used them last night for my scopes. Everything worked great. Then I charged them with me 100W solar panels during the (very sunny) day. In the evening I tried to use them again, but both gave up very quickly.

Did some research and found out that they need special charge controllers as their charge profile is different. After lots of research I bought new charge controller from Morningstar. In about a week will I find out if and how much of a difference that makes...

Wednesday, July 12, 2017

Mauna Kea Observatories

My personal highlight of our Hawaii vacation was a summit tour of Manua Kea to watch the sunset. Initially, I had SO many ideas for photos and videos to take. But I ended up taking a few and then setting the camera into auto mode to take images for a sunset timelapse ...
... and then just taking it all in!!!

First, the timelapse:


And then some of the amazing photos that can't capture the moment.
The Subaru telescope (left) and Keck I and Keck II.

My friend Patrick in front of UH88

The CHFT

Taking Photos

Me and Patrick
Star gazing under the Milky Way on our way back down

Tuesday, June 13, 2017

Blew my MyT electronics board and NUC...

The disconnects of my MyT mount were (apparently) related to the 12V->48V converter that I used. When I wanted to check it out further, the converter shorted and took the MyT control board and the NUC down ... SH###!!!

So, I need fuses (as Richard always told me) and I need them such that everything works from home and in the field. This lead to this project to create a setup that I can use at home and almost exactly the same way in the field.

Eclipse MegaMovie

I love what seemingly random projects we sometimes do!!!

In this case it's Eclipse MegaMovie 2017 - a lot of info about the upcoming eclipse including simulator how the eclipse will look from arbitrary locations.

Sunday, June 4, 2017

PDF focuser weirdness

Suddenly my (fairly new) FLI PDF focuser acted up:
  1.  I move the focuser to 2500
  2. Then I move it to 2501 (using the FLIFocuser app to make sure that this isn't a problem with some other software) - I can see that it moves first to 2506 and then back to 2501 (I guess it has a 5 step built-in backlash compensation?)
  3. Then I move it to 2502But now it only moves it to 2496 !!!!
    It somehow didn't execute the +1 step from me or +5 step from the first part of the backlash compensation. But only the -5 backlash compensation.
And it happens A LOT! I tried all three speeds (Slow, Medium, Fast) or I tried other step sizes - always the same.

Asked Richard, Richard, Jim and John and also sent an email to FLI...


Saturday, June 3, 2017

Same setup at home and in the field

I find it always tricky to move my scope into the field and make sure that everything works. The main two challenges are:
  1. Powering everything from 12V batteries
  2. Using my laptop vs. the NUC on the scope for control.
1. Powering everything from 12V batteries
I decided to start using a 12V power source for everything. So, when I get into the field, I just replace that one with 12V batteries and everything should work exactly as before:
  • Most equipment runs off 12V anyway (focuser, filter wheel...) - Just need coaxial plugs (2.1mm and 2.5mm) with Anderson connectors.
  • The NUC computers can run off 12V.
  • The FLI cameras need 12V-12V DC/DC converter
  • The MyT mount needs a 12V-48V DC/DC converter
All connections need to be secured by fuses. Actually, I should have done that a long time ago. But was "reminded" of it when I blew up my NUC AND the control board of the MyT mount :-(

For that, I measured the power usage of all components:
ComponentPeak Power UsageFuse
FLI ML160705A
(cooling at 100% and taking continuous images)
7.5A
FLI MLx6942.8A
(cooling at 100% and taking continuous images)
5A
NUC computer2.2
(network usage, storing, CPU usage)
3A
MyT mount4.2A
(when full slewing)
5A
MyT equipment
(FLI FW, FLI PDF, Dew Heater, Grasshopper3, USB Hub)
1.3A2A
Mach1 mount1.2A
(when full slewing)
2A
Mach 1 equipment
(FLI FW, FLI Atlas, Lodestar, Dew Heater, USB Hub)
1.7A2A
Lunt Pressure Controller, Microtouch Focuser<1A1A

I bought a RigRunner to power all components on the scope and have just one main power line from the 12V power supply. The RigRunners are great for this as they have blade fuses integrated:

Now, with the NUC computer on the scope, I have all USB cables running there and only one (actually two - see below) cable running from the scope!!!:

Now, when I take the scope into the field, I can either replace the main line with one battery, or depending on power usage at night, power individual components (then with inline fuses) from a battery!
2. Using Laptop vs. NUC for imaging
The other change in the field was always that I used the NUC for imaging when I was at home and then my laptop when I was in the field. Which means that I had to copy profiles... over to the laptop - and often realized too late that I was using an older profile or such (e.g. with older focusing setup).

So, instead, I want to use the NUC always for imaging. They are great as they can be powered by 12V, i.e. don't need any converter or such.

At home, I usually used the wireless network card of the NUC to connect with them, which of course meant that I would need a different setup in the field (IP address!)

I did a little bit of research and found out that Ethernet is a little less power hungry then WiFi anyway. So, in the field I will use Ethernet to connect the scope and the laptop for remoting into the NUC. In order to use Ethernet at home too, I did the following trick: use one of our Google Wifi devices on the scope. I connect the NUC to the Google Wifi device and now I can connect from my laptop from inside via Wifi.

Finally, I use reserved (static) IP addresses for my laptop and the NUC, so that I can use the same IP addresses at home or in the field.

To power both of my scopes, I bought a small Ethernet switch which had only 2W input power (with 12V, that's less then 0.2A!!!) At home, I plug the Google Wifi into the switch, in the field I plug my laptop into the switch. No IP address changes or anything!!!

And with all this, most cables and components are now on the scope and won't change. Which makes the whole setup WAY less cluttered!!!

Monday, May 15, 2017

Sudden disconnects from MyT mount

On Sunday, when I tried to take some sun images, my MyT mount suddenly started to disconnect. At first, I thought that it is just a fluke thing, but then it happened pretty reliably every time I gave a slew command from TSX.

I saw two error messages:
Device: Mount
Error, poor communication, connection automatically
terminated. Error = 213.

Receive time-out.COMM_TIMEOUT . Error = 21002.


After the slew ended I could connect TSX again...

Tried a different USB port or a different cable, both with the same result.

I then tried with my other NUC and my laptop - both worked fine. So, it seems to be something about the computer. I then tried to power the mount and/or the NUC separately to make sure that there is enough power, but always with the same results.

Finally, I posted in the Bisque forum.

... maybe it is the 12-48V converter ...

---

Yes, it was the converter. And when I investigated it more, I blew the controller board and the NUC !!! :-(