Hi jabian,
In the GPS NEMA driver, there is a refresh parameter that tells the driver how often to refresh. If you set it to 0 (zero), then the driver won't refresh the position and time from the nema source again.


Hi AirBourn,

In short: with the android app "Share GPS" and the INDI GPS NEMA driver.

With the app, you can share a NEMA stream via Network.

The INDI NEMA driver needs to know the IP address of the phone. I use the small TP-Link travel router (30€) on the telescope to manage the network and give fixed IPs to all devices.

In the app, I set up a connection with the following settings:
Data Type: NEMA
Connection Method: TCP/IP
Port: 50000
TCP/IP Server: act as server and listen for incoming connections

I first connect my phone to the network and start the app. I then start a gps application on the phone and make sure I have a position fix. Then I connect the indi driver. It usually gets the position immediately and also syncs the exact time for KSTARS.

For some reason, this method stops working after the intitial connection. The indi driver can't get a connection to update the position or time again without restarting everything. I don't know if this is a problem with the driver or the app. But I only need the position and time sync once at the beginning of a session anyway.


Hi cofford,

I am 99% certain it is an issue with USB3.0 connections causing em interference with the GPS Signal.
you can test this by operating the UBlox 7 Module on a completely seperate device (for example a windows laptop), but in very close proximity to the rest of the setup.
As soon as you turn your setup on (including the USB3 connection to the astrocamera), you will lose GPS Signal. It has nothing to do with drivers or software problems. It is sadly just electromagnetic interference.

I ended up ditching the Ublox 7 gps dongle, and streaming the GPS Data from my phones GPS instead


For weeks I couldn't figure out, why my GPS USB Dongle (10€, U-Blox7) didn't work with Stellarmate on RP4. If anybody has similar problems, I hope this post helps them:

On the PC or with RP3, the GPS Dongle will get the current positon in a matter of seconds. On the RP4, I could leave it running for hours without a fix. GPSD lets me see that the dongle is picking up the signal of many satellites, but for some reasons there was never a fix possible.

Today I realized, that the USB3 connection of the RP4 interferes with the GPS Signal. It depends on the connected device: A CMOS camera or USB-Stick connected by USB3 doesn't cause much interference. But as soon as I connect the PegasusAstro Pocket Powerbox Advance via USB3, the GPS can't get any usable signal anymore. Even if the GPS is pluged into a completeley different device 50cm away, the interference is still too strong.

I now connect the Powerbox only via USB2, that solved the problem and I can use the GPS dongle without issues. Of course this has the downside that I can't use the USB3 speeds at the Hub on the Powerbox anymore. Luckily the only two devices that I need USB3 speeds for (Camera and USB-Storage) can fit on the RP4 directly and don't cause too much interference.


I also experienced this issue randomly a few times. I couldn't figure out why it sometimes happens. The easiest workaround is just to ALWAYS enable Timestamp (TS) in the filename for each sequence. Even if all frames have the same number 001, they still have different names because of the timestamp, so they won't override themselves.


Elias Erdnuess replied to the topic 'For those with focus issues' in the forum. 3 years ago

Hi universalmaster,
I had very similar issues than you:
1.) The HFR values are "noise", so to get a reliable v-curve, I either had to use long focus-exopsures or averaging over many frames. This made autofocus very slow and not practical.
2.) When focusing with the full field, the different detection algorithms either detected to few stars, or to many "false" stars (noise, hot pixel).
3.) The the different focus algorithms move all very far out of the focus, so that eventually they don't recognize stars properly anymore. That gives completely wrong measurments for the HFR values at the edges of the v-curve.
All these issues prevented me from using autofocus automatically and without supervision.

I found a solution I am very happy with:
- Don't focus on your actual target, but focus on a bright star close to your target (really bright). (create a "fake" job in your scheduler, to slew to a bright star and focus, before slewing to your actual target).
- With a short focus-exposure time of 0.5 seconds, star detection "gradient", "Auto-select star" and "subframe", the algorithm reliably picks up the very bright star as the target to focus on. The short exposure time and the subframing means, that you can rapidly take many frames to get a more averaged (and less noise hfr measurments). (I average over 8 frames)
- The linear algorithm works best. Even if it moves far away from the minimum of the v-curve, the star is so bright that the algorithm still detects it reliably.
Because the v-curve is very clear and not noise at all, I can choose a tolerance of 0.5%.

With these settings, the automatic focuser works without intervention flawlessly and very quickly.

The only downside is the requirment to work with "fake" jobs in the scheduler, to slew to the bright focus-star of your choice.


Thank you for your responses and feedback to this suggestion. To summarise and clarify these seem to me to be two more or less separate points:

1) Having the option to add a specific focus target for any job. From a users perspective, It seems to make most sense to place this option in the scheduler, after I select the target and sequence. Whenever it comes to autofocus, the mount would slew to this target, and then slew back to the imaging target afterwards.

2) Having the option to enforce align and/or guiding before autofocus. Choosing a specific focus target makes little sense, if it isn't ensured by the align module to actually be in the field of view. And starting guiding before autofocus can allow for longer exposures while autofocusing (most focusing issues seem to be from not high enough SNR on the stars). As a user, I would expect to find this option in the focus module, next to where I can find the "suspend guiding while focusing" option.

Stay healthy everyone, Elias