Monday, April 24, 2017

Exact Location and Time in the field

Several tools (e.g. TheSkyX - or especially T-Point) need the exact location and time. With an internet connection it's not a problem at all:

  • Android Phone for location
  • Dimension 4 for exact time
But how to get this when we are in the field without an internet connection. I'm always surprised how many Android apps need an internet connection - even if their functionality doesn't really need them. And Dimension 4 will not work at all as it connects to Internet Timer Servers.

The best solution I found was describe in Using GPS Receivers to Set Computer Time for In-the-Field Logging by Gene Hinkle. It requires:
Setup of GPS device is simpl: install driver, plug in device, install and start GPSInfo program. It might take a couple of minutes until the program found enough GPS satellites to determine its location:

(It should automatically detect the right COM number)

Now, close GPSInfo and start NMEATimePanel. It will first synchronize:

... and then after a while, it will lock to the satellites:

And now it will correct the computer time. Usually it gets it down to a few milliseconds.

Monday, February 6, 2017

Comparing Narrower and Wider Narrowband Filters

In my recent narrowband images, I needed very long exposure times to get a decent signal in OIII and SII. And I was wondering if the small window of the Custom Scientific filters (Ha 4.5nm, SII 3nm, OIII 3nm) are maybe too small. And that they remove a lot of the background noise but also leave less of the signal through.

So, I bought Baader narrowband filters that are significantly wider (Ha 7nm, SII 8nm, OIII 8.5nm).

In order to compare them, I shot images of the jellyfish nebula. It has a very strong signal but also dark areas nearby. In order to minimize the influence of changing seeing conditions, I shot one hour with one filter, then one hour with the other and then again with the first and so forth.

I'm still struggling with my unreliable lodestar guider, so I had to throw away a number of images. But ended up with enough data to compare them. I decided to compare them by contrast and signal to noise ratio.

I calculated contrast by first measuring average signal in a bright area and in a dark area


and then calculating it Contrast = (Bright - Dark) / (Bright + Dark)

For Signal to Noise ration I measured the images with Pixinsight's subselector script. It doesn't report absolute values but relative values.

Here are the results:

BrightBackgroundContrastSNR
Ha 4.5nm3.50E-047.83E-056.34E-012.099
Ha 8nm4.84E-049.95E-056.59E-014.114
OIII 3nm1.54E-049.62E-052.30E-011.543
OIII2 8.5nm1.67E-041.07E-042.18E-012.481

The contrast is very similar between both filters. But the Signal-to-Noise ratio is significantly better with the wider filters.

The other question is how bad the background gradients are that get created with both filters. I used the OIII images to compare as the Jellyfish nebula is very weak in OIII:

3nm8.5nm

Using AutomaticBackgroundExtraction, I get the following background images:
3nm8.5nm

Clearly, the wider filter has larger gradients. But after the first background removal the residual background is:
3nm8.5nm

Looks like we can remove the stronger gradient fairly easily.

So, this does seem to support my suspicion, that the smaller narrowband filter extend the integration time. Although I am not sure what the reason is - the Ha/SII/OIII signal should be the same with the smaller and the wider filters.

Anyway: I'll probably stick with the wider narrowband filters.

Guiding failures - every night!!!

In the past, I have seen (every couple of months) an error like:

02:01:45.323 00.000 5728 invoke imageready:
(ASCOM.SXCamera) Unable to complete get_ImageReady request due to previous error

during my imaging sessions. After that every image capture fails in PHD2.

Suddenly, I see these errors every night - sometimes after a few minutes after a few hours.

As I didn't make any software changes, I first thought about a hardware issue:
  • Replaced the USB cable
  • Switched the Lodestar X2 for my older Lodestar guider
Without any improvements.

I then
  • Updated PHD2 to the latest version
  • Updated the StarlightXpress driver to the latest version
  • Reverted SGPro back to the last working version
With the same results.

Finally posted in the PHD2 forum for help. I also asked Richard and the others. Everybody points to the USB connection (cable, Hub...) I tried
  • Using a different cable
  • Connecting the guider directly to the computer
  • Using a different hub
... always with the same results.

Somebody on the PHD2 mailing list mentioned that it might have something to do with the temperature. Not that it's REALLY cold here, but it does get below freezing.

Saturday, December 17, 2016

SGPro can't connect to my FLI camera anymore!!!

I finally cleared up and I wanted to take the remaining data for my Heart Nebula image. Set everything up. Checked everything (so I though during the day) and when I wanted to start imaging...

... SGPro couldn't connect to my FLI camera anymore!!!

I clicked the connect button, it would turn to green and then after a while would disconnect again. In the SGPro logs I could see:

[12/17/2016 7:08:41 PM] [DEBUG] [Main Thread] Connecting camera in main thread...
[12/17/2016 7:08:41 PM] [DEBUG] [Main Thread] Connecting FLI camera...
[12/17/2016 7:08:41 PM] [DEBUG] [Main Thread] Querying for FLI USB cameras...
[12/17/2016 7:08:41 PM] [DEBUG] [Main Thread] FLI Camera Name: MicroLine ML16070(HW: 256; FW: 292)
[12/17/2016 7:08:41 PM] [DEBUG] [Main Thread] FLI Library Version: Software Development Library for Windows 1.104
[12/17/2016 7:08:41 PM] [DEBUG] [Main Thread] FLI CCD Dimensions: 4954x3300
[12/17/2016 7:08:41 PM] [DEBUG] [Main Thread] FLI Visible CCD Dimensions: 4864x3232
[12/17/2016 7:08:41 PM] [DEBUG] [Main Thread] FLI Pixel Size: 7.39999995857943E-06x7.39999995857943E-06
[12/17/2016 7:08:41 PM] [DEBUG] [Main Thread] FLI Camera Mode: 0
[12/17/2016 7:08:41 PM] [DEBUG] [Main Thread] FLI Avaialble Camera Modes: 
[12/17/2016 7:08:41 PM] [DEBUG] [Main Thread] - 0: 11 MHz
[12/17/2016 7:08:41 PM] [DEBUG] [Main Thread] - 1: 4MHz
[12/17/2016 7:08:41 PM] [DEBUG] [TEC Thread] SGM_CHANGE_COOLER_TEMP message received...
[12/17/2016 7:08:41 PM] [DEBUG] [TEC Thread] TEC Change: Starting...
[12/17/2016 7:08:41 PM] [DEBUG] [TEC Thread] TEC Change: After camera connect change, waiting ~5 seconds...
[12/17/2016 7:08:46 PM] [DEBUG] [TEC Thread] TEC Change: Attempting to turn the camera cooler on...
[12/17/2016 7:08:46 PM] [DEBUG] [Main Thread] Turning camera cooler on...
[12/17/2016 7:08:46 PM] [DEBUG] [Main Thread] Turning camera cooler on...
[12/17/2016 7:08:47 PM] [DEBUG] [Equipment Connectivity Thread] SGPro thinks the camera is connected, but it's not, syncing UI...
[12/17/2016 7:08:47 PM] [DEBUG] [Equipment Connectivity Thread] Adding sequence level notification: External disconnect of camera detected...
[12/17/2016 7:08:47 PM] [DEBUG] [TEC Thread] SGM_CHANGE_COOLER_TEMP complete...
[12/17/2016 7:09:12 PM] [DEBUG] [Main Thread] Turning camera cooler off...
[12/17/2016 7:09:12 PM] [DEBUG] [Main Thread] Disconnecting FLI camera...
[12/17/2016 7:09:13 PM] [DEBUG] [Main Thread] Turning camera cooler off...


Tried various things (restart SGPro, restart computer, different cable...) with no effect. The weird thing was that other apps (FLI Grab, TSX) could connect and use the camera.

I posted on the SGPro mailing list and it seems as if this is a regression in one of the latest builds. I tried 2.5.2.8 and 2.5.2.6 without luck. Only when reverted back to 2.5.2.3 (quite old!) it that worked. Phew!

Sunday, December 11, 2016

Remote Control of the MicroTouch focuser

I started with the MicroTouch Controller app:

It had quite a number of issues:

  1. Setting the Target Position
    When I tried that, I got an error message "Value Entered Out of Range. Must be between 0 and 0".
    Upon checking the "Setup" tab, I noticed that both the "Min Value" and "Max Value" were set to 0. When I tried to set the "Max Value" to a larger number, it seemed to do something (app was blocked for a second or two). But when control returned, it was still set to 0. Tried many things, always with the same result.
    It then wasn't surprising that I couldn't set the
    "Min Value" - it always gave an error: "Min Position must be less than Max Value".
    I also checked the Diagnostics tab, but it showed 0 corrupted packets and 0 packets dropped.
  2. Updating Firmware
    Next thing I tried was to update the Firmware of the controller. Mine was at 3.8, the last version was 4.4. I used the MicroTouch Flash Loader app

    I selected the 
    MicroTouch_4_4.bin file. But when I press "Program", the Status changed from "Idle" to "Opening USB Port" ... and then nothing happened. Always the same result
  3. But I could change the focuser position with the IN and OUT button on the handcontroller, so I thought that I should be able to change it with the up and down arrows in the Controller app. But nothing happened when I pressed those.
    ... until I plugged in a mouse (instead of using the Asus touchpad)! Then the buttons suddenly worked!!! I have absolutely no idea what this is about. The touchpad click should trigger the exact same even then a mouse press...
    Well at least I know now how I could use it.
  4. From SGPro
    In SGPro, I selected "MicroTouch Focuser 1" as my focuser (the app / handset is able to control 4 focusers in parallel). Then I clicked setup ... nothing changed. Until I noticed that SGPro opened a new window UNDER its own window (I think I noticed that with other popups before). This was the "MicroTouch Focuser Setup" popup:

    I opened the drop down menu of "Focuser 1" and selected the entry 1532 - I guess that's the serial number of my focuser ...
    Then everything worked in SGPro! Could move focuser in and out and also set absolute positions!!! (unlike in the MicroTouch Controller app)
  5. From TheSkyX
    There were some instructions in the MicroTouch drive/app package to copy certain files into the TSX directories. But when I tried that, the same files were already there. Seems as if TSX is packaging these up right now. But when I then tried to connect to the focuser I always received an error "No connection to the device. Error = 215."
    And when I then read the instructions again, they said that I would need firmware version 4.4 in my controller to connect to it. So, back to #2.
I sent an email to Starlightinstruments and asked for help with #1 and #2...

Saturday, December 10, 2016

PC-USB Pressure Tuner Controller for Lunt Scope

In addition to focusing, I also want to control the pressure tuner from the computer. Luckily, Lunt offers the PC-USB Pressure Tuner Controller. I ordered it and after a few weeks it arrived.

It consists of:
  1. AC/DC adapter (15V)
  2. Air Pipe
  3. Large and Small O-rings
  4. New cover cap (with a hole in the middle)
  5. A different Piston
  6. A USB stick with the software
  7. Instruction sheet
  8. The PC-USB unit
Most notably absent were proper installation instructions ...


1. Unscrew the pressure tuner
2. Unscrew the cover cap
3. Take the little screw out and remove the piston. I found that it was easiest by putting the pressure tuner on a paper towel as the piston inside was very greasy:
4. Now insert the new piston
5. And now insert the new screw (with a hole in it) and tighten the piston

6. Finally put the new cover cap (also with a hole) on it:
and put the pressure tuner on the scope again (tighten it all the way)

Now, we connect the pressure tuner with the air pipe to the PC-USB unit

Powering on the PC-USB unit shows:

And once done, we can set a target pressure and the unit will adjust accordingly (you can hear the pump in the unit working!) It usually sets the pressure slightly higher and once the pressure drops, it will increase it again to stay around the target value.

---

Micro Touch Focusing System for the Lunt scope

Of course, I wanted to focus my new Lunt scope also from the computer. Luckily, I still had a Micro Touch Focusing System that I once tried to use on my Edge scope. I checked with Wayne from Starlight Instruments and it turned out that I could even use the MSM20 stepping moter from the EDGE scope.

... but when I tried it, the motor didn't work well - got stuck from time to time, so I had to order a new one.

Installation of the motor on the Feathertouch Focuser is fairly simple. The motor gets attached on the side of the red micro focusing cog:

1. we unscrew the red cog:

2. we unscrew the black wheel:

3. Take the little cog that came with the MSM20 motor

push it flush on the axis and tighten the screw

Finally, take the motor

Push it onto the axis. Might have to wiggle it a little to make sure that the two cogs interlock

until it is completely on the axis and you can't see any silver anymore

and finally tighten the screw:

And now we connect the motor to the Micro Touch Focusing unit and can either more the focuser in out with the control box

Next was to control the focuser from the computer - which turned out to be very tricky.