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kens

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Everything posted by kens

  1. I had something similar, a delayed on relay, but it had an issue. The relay was operated by 5V but the input circuitry had a reverse polarity protection diode which dropped the voltage to the relay enough to prevent it from activating. So I had to add in a buck boost to take the voltage to 5.5V (from memory)
  2. Simplistically that works because the angular corrections would be correct. In reality, a large deviation between the guide camera and imaging camera leads to field rotation from polar alignment error. Plus it is simpler to just tell PHD2 what the declination is and let it adjust than to repoint the guide scope. http://celestialwonders.com/tools/rotationMaxErrorCalc.html
  3. When you are pointing at the pole you will see very little movement in RA. The circles of RA get smaller and smaller as you get near the pole like latitude on earth. But it still takes 24 hours to go around those circles. So near the pole the movement around the circle is very slow. The movement is largest at dec 0 - aka he celestial equator/CE Your guide log shows you took 26 steps to calibrate. Assuming the guide rate, pixel scale and calibration steps are all accurately calculated that would suggest you were pointing around dec 60 or 70 where the RA movement is about half what it is at dec 0. With mounts that report their coordinates, PHD2 can calibrate near dec 0, where it is most accurate due to the large RA movement, and use that calibration on any target by applying a correction to the guide pulses. Using the On Camera mount this is not possible so you must calibrate on target. You can try adding as an Aux Mount the "Ask for coordinates" driver. This asks you where you are pointing every time you guide and allow PHD2 to make the necessary corrections. You don't have to be precise - within a few degrees would be ok. Why did it work this time? Could be any number of things. The main one I can think of is that previously you had not allowed the RA backlash to clear before calibrating, after moving onto your target. Or you might have been calibrating too close too the pole Can you clarify something you wrote above. You gave me the impression that you move the guide scope relative to the DSLR so they are pointing in differenet directions. That's a no-no
  4. Backlash is a common problem in gears that occurs when they change direction. It takes some time for the gear teeth to make contact in the new direction before the driven gear starts to move. On a mount this most often occurs on the declination axis as the RA axis does not change direction while tracking. It can also occur on the RA axis after slewing. You can adjust your gear mesh to minimise backlash. Then you can try using the PHD2 Guiding Assistant to measure your backlash and then apply the Backlash compensation tool in PHD2. This wil only work if the backlash is not too severe. You can also force PHD2 to duide in declination in one direction only. For this to work you can deliberately maintain a Polar Alignment error that ensures a steady ddeclination drift in one direction and only guide against that drift. I suggest you read up on the Guiding Assistant then run it. https://openphdguiding.org/manual/?section=Tools.htm#Guiding_Assistant You can attach the guide log here or on the PHD2 forum for more advice. https://openphdguiding.org/getting-help/ The guide log location can be found from the Help menu. (Screen shots are generally not useful)
  5. Stellarium does allow control of the telescope via INDI using the Telescope Control plug-in. So you can install Stellarium on whichever platform you like and run it alongside Kstars/Ekos. Just like you can with PHD2.
  6. Please read this: https://openphdguiding.org/getting-help/ I would suggest posting in the PHD2 Forum as this will require analysis of your Debug log to work out what is going on. Follow the instructions to upload the logs to the PHD2 Forum
  7. The blue target thing is a bookmark. You can clear it in the Bookmarks menu
  8. @Nikodemuzz I don't profess to know anything about the CEM60 but looking at your scenario photos I can't see how scenario 2 could work whereas scenarios 1 and 3 both look normal to me. USB hubs are arranged in a tree and link from one branch (port) from the computer to the trunk of the next one (e.g. on the saddle) which then provides more bracnhes (ports). In scenario 2 you are connecting the branch from your computer to the branch of the hub on the saddle. I suggest you ditch your USB-A to USB-A cable and get a standard USB-A to USB-B In a conventional setup you would use go from a laptop via USB-A to USB-B to the port next to the polar scope. A separate USB serial cable goes from the laptop USB to the mount serial port. Cameras, filterwheel, focuser etc connect to the USB ports on the saddle. I cannot understand why you say this has no practical application. This is functionally equivalent to your scenario 3 with the Asiair being used instead of a laptop.
  9. You cannot guide without a good calibration first. The mount appears to be moving but so slowly that it might just be drift. What declination did you calibrate at? You will need to calibrate on your target but for testing you should calibrate near dec 0 to get the maximum RA movement. Cable issues are very common with ST4 so that is a possible cause. You could try the manual guide option on the Tools menu or the Star Cross test (although it wont show anything for Dec of course) for more data on the problem. EDIT: As to your question n east movement: this just slows down the mount so there is no backlash. But when you move to your target, before calibrating make sure the last movement of the mount is north and west to remove any backlash.
  10. Polar alignment and star alignment are different things. Polar alignment sets the mounts RA axis to point at the celestial pole so that it tracks accurately. This is essential although some people go overboard. As a general rule, accuracy to within about 5 arc minutes is sufficient. Star alignment adjusts the coordinate system so that gotos are accurate. This is not really necessary when imaging as you can use plate solving to get precisely on target. It can be handy for observing so you don't need to go hunting around for your target.
  11. @5haan_AI'm surprised that nobody has asked you to attach your guide log FILES rather than relying on screen shots. Screen shots are, frankly, useless for diagnosing issues. The help menu will take you to the logs. A quick glance at the screen shot does suggest that you have your guide rate set to 0.1x sidereal. The logs would help confirm this. It should beat least 0.5x. Unfortunately the EQMOD driver defaults to 0.1x which is an unsuitable value in most cases. Ther may also be other issues but that would be a good starting point.
  12. 3 minutes PA error is not a problem. PHD2 was able to keep the guide star centred in the guide camera but the image camera shows a steady drift. So one camera is moving in relation to the other. My first guess would be that the dec blips are a result of the guide scope moving. Given the dec movement I would look at whether it is rotating slightly where the guide scope is attached to the main scope. We are talking microns here. Irrespective of that, you also appear to have backlash or stiction issues.
  13. If the guiding was OK (a guide log would be helpful), then it would be differential flexure of some sort. The "blips in dec" may offer a clue.
  14. In addition to some pulse guide fails there are also a couple of capture fails on the camera. I can see you had to restart guiding but what else did you do? e.g. did you check the camera connection at those times? Getting intermittent pulse guide fails and capture fails is suggestive of a USB connection problem. Combined with the intermittent large jumps points to cable snags as a common cause but of course they could be independent issues. If not cable snags causing the jumps then another possibility is flexure in the guide scope.
  15. Could you post a guide log and maybe even the debug log? For instance, it could be that there is a long wait time for the mount to respond causing delays on each expsoure
  16. Just to give you food for thought... The most important piece of kit for imaging, especially for DSOs, is the mount. Opinions vary, but I would think that the mount would take up at around half the budget of your kit overall. Looking at your budget , you would appear to be underdone with an EQ5 mount. Many would consider the HEQ5 as a sensible minimum. Most of the frustrations with imaging stem from the mount so if you are after something that is simple and fun you should consider your choice of mount.
  17. The graph of way your mount behaves, guided or unguided, can be broken down into a series of sine waves of different frequencies, amplitudes and phases. So the frequency response is the graph of amplitudes against frequency (or period which is 1 divided by frequency). What I look for is spikes at significant periods. You can see on the frequency response from your guided mount there are two spikes at periods of 480s and 10.2s. The 480s spike corrresponds to the fundamental frequency of your mount - the time it takes the worm to rotate once. It's possible this could be reduced e.g. by increasing aggression (currently 0.5 which is lower than the default of 0.7) The spike at 10.2s is as discussed but is harder to guide out. The smaller spike at 122s corresponds (to my memory) to the time it takes the motor gear to make one revolution.
  18. I analysed the guide log with PHD Log Viewer https://openphdguiding.org/phd2-log-viewer/ @wimvb beat me to it. It has an option to graph the frequency response of your RA axis both with and without guiding pulses. This shows a strong response at 10.2 seconds.
  19. As @wimvb says you are getting close to the limits of guiding precision at that pixel scale. But you do have a spike in the frequency response at 10.2s which is the gear tooth mesh period. Try adjusting the belt tension.
  20. The markings on the mount are not necessarily highly accurate and even if they were they would also rely on the mount being level. If the software says that's where to move the mount to it is probably right.
  21. You wont hear a thing when guiding. You'll only hear it moving when you are slewing.
  22. During calibration it was moving a tiny amount. Overall just a few pixels so you would not be able to see the movement on the screen. Now its possible that movement was just due to normal periodic error drift but it looked quite linear
  23. From your guide log I can see that you were tracking (or were pointing at the pole) as there was no significant drift in RA. The amount of information available with ST4 guiding is unfortunately very limited. But some of the calibrations do show steady movement in RA. So if you were pointing well away from the pole it may be that the guide rate set in your hand controller was simply too small. This is certainly an issue when using the EQMOD driver. Check the guide rate in the hand controller and make sure it is at least 0.5x sidereal. Using an EQDIR cable will make it easier to diagnose any problems. When you get your EQDIR cable start by creating a new profile in PHD2 with the wizard. Also, read the best practices document: https://openphdguiding.org/phd2-best-practices/ Especially, follow the instructions for using EQ-ASCOM with PHD2 at https://github.com/OpenPHDGuiding/phd2/wiki/EQASCOM-Settings
  24. Please find the relevant PHD2 Guide Log. It is usually under Documents\PHD2 and has the date and time your guiding session started. Zip the file and attach it for analysis. When you say the star moves out of the screen "like normal" - that is not normal behaviour if the mount is tracking properly and your PA is not hugely off. Also, can you describe roughly where the scope was pointing when you started guiding e.g. was it in the same place where you did your Sharpcap polar alignment? For this to work you need a USB connection from computer to mount. An ST4 cable is not sufficient for controlling where the mount is pointing. PHD2 and ST4 will only make tiny corrections to the mount to account for slow drift of the mount.
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