kbrown

Thanks for the suggestion but unfortunately there's no difference between vnc or local display. I did some more poking around. I compiled another program called Planetary Imager to see whether it's any better. It suffers from the same behaviour. Then I thought maybe it's due to the 32bit Raspberry Pi OS so I installed the 64bit beta version. Again no difference. However with Planetary Imager I'm getting these warning as soon as the FPS drops down to unusable: WARNING - void ImagerThread::Private::thread_started() ASI error TIMEOUT: timeout (code: 11) on Capture frame (/home/pi/Documents/dev/git_repos/PlanetaryImager/src/drivers/zwo_asi/asiimagingworker.cpp:115) I had usbtop running in terminal while this all was happening so I could see how much data was actually coming from the camera. While everything was working (1536x1024 ROI) the data rate was around 4000-5000 kb/s which is easy peasy for USB3. When the above warnings were coming into play there was barely any traffic at all. Feels like it's a problem with the libASICamera2 (at least with ASI174MM) for armv7 and armv8 since three different capture programs suffers from the same symptoms... Would be great to hear if anyone has had better success with higher than 1536x1024 ROI with reasonable FPS using any ASI cameras? I have a ASI183MC Pro as well. Will try that next... EDIT: Ok this is interesting. With my ASI183MC Pro I was able to get fairly stable 2.2FPS at 5496x3672 (BGR24)! And about 6FPS if I changed to RGGB8 mode. At 1920x1080 (RGGB8) I get a stable 70FPS! Go figure...

Yes I saw that. It seems to relate to usb storage devices only. I tried it with my camera's vendor and device ids but it had no effect. Even dmesg didn't show the quirk was applied.

Yes, I have considered that and tried all sorts of combinations. Even at the native maximum 1936x1216 I get < 1 FPS via USB3 and just mostly dropped frames which is completely unworkable. Via USB2 this was 14-15FPS?!? A new finding just now was that if I keep the vertical ROI at 1024 and play around with just the horizontal one, I can get to 1536x1024 at about 55FPS. But then 1600x1024 is barely working at all. On my laptop (oacapture) I get something like: 1936x1216 -> 103FPS 640x480 -> 250FPS 320x240 -> 466FPS 1024x1024 -> 122FPS 1536x1024 -> 122FPS 1600x1200 -> 103FPS It really feels like there's something wrong with the USB3 ports on the RPi4 or the libASICamera2 library. Going via USB2 shouldn't be faster than USB3!

Hi, I've been trying to find a solution for this problem for several days now without success. The issue is that I cannot use a ROI larger than 1024x1024 in oacapture or firecapture running on RPi4 (4GB) when my ASI174MM is connected via USB3 port. At 1024x1024 ROI I get about 60FPS (not recording, just viewing). If I increase the ROI even a little bit, say 1024x1028, the FPS will be < 1 and I get a ton of dropped frames. Playing around with the USB Traffic setting does not help at all. Both oacapture 1.8.0 and firecapture 2.7b.5 behave like this. Things that I've tried: Different USB3 cables. Plugging the camera directly to the RPi and via a powered USB3 hub. Disabled WiFi, Bluetooth and the RPi is running headless without a HDMI display (I've read about some RF interference cases relating to this) Replaced the libASICamera2.so library files with the latest form ASI SDK (libASICamera2.so.1.20) for both oacapture and firecapture. Updated RPi software and firmware to the latest. None of the above made a difference. What is interesting that I get better results if I plug the camera to an USB2 port on the RPi4. With USB2 I get about 14-15FPS at full resolution? Any ideas?

It's also not a good idea to constantly let lead acid batteries to completely discharge as sulfation will happen and degrade the battery faster.

I just re-read what you wrote and now have a better understanding. The 100mm was basically a guesstimate to put the focuser somewhere in the middle of the travel when the system is in focus plus ensuring the tube isn't in the light cone. That would leave me a little bit of in and out travel should I ever need it for anything. That was the thinking anyway. Not sure it this makes sense though?

Thank you Phil! Really appreciate you took the time to look into this! My new secondary mirror hasn't arrived yet so I have still time to study what you've just said. Haven't thought about moving the primary mirror. Initial thought is it's not possible but I will think about it...

Thank you. I'm pleased with it. It's basically the first I've done with this scope. Auto focus worked great with Ekos btw.

Happy to announce it is going well, thank you! I've now finally had a chance to use the NEMA17 version of the focuser for a few nights and it is working really well. Here's a SHO false colour rendition of The Pelican Nebula I took over the past few clear sky nights using my William Optics Fluorostar FLT91 and this focuser: I've also made an initial publish on the project files on my Website and GitLab. It's all still a bit raw but at least you'll be able to get your hands on it. I'll be updating this further once I get a chance. Please don't hesitate to ask here or on my website if anything is unclear.

Hi, Just wondering if someone could validate my ponderings before I start drilling new holes on my Skywatcher 250PX. Here are the current key scope parameters: Primary mirror: 10" / 254mm Focal length: 1200mm Focal ratio: 4.72 Secondary mirror minor axis: 58mm Tube inside diameter: 286mm Tube wall thickness: 1mm Focuser to front of tube: 128mm (ish) Mirror face to back of tube: 72mm (ish) Focuser minimum height: 76mm (**1) Spare focuser in travel: 16mm (**1) Additional height for camera: 55.667mm (**2) Focuser inside diameter: 51mm **1) The 76mm focuser height is the height from the top of the focuser to the outside of the tube when the scope is roughly in focus with my imaging train. The 16mm spare in travel is how much I can focus in from this position. **2) The distance from the top of the focuser to the sensor + 1/3 thickness of a filter. Using the Newt for the Web calculator it tells me the secondary is too small to admit 100% ray. The new focuser is a Baader Diamond Steeltrack with the optional ClickLock S58 clamp. Unfortunately this combination is higher than the 76mm mentioned above. Furthermore at minimum height the focuser tube would be in front of the primary mirror. So with these in mind I'm planning to switch the secondary mirror to a bigger one and move the focuser closer to the primary to "push out" the focal plane further outside the tube. The new modified parameters would be: Secondary mirror minor axis: 75mm Focuser minimum height: 100mm (**3) Spare focuser in travel: 27mm (**3) Focuser inside diameter: 55.4mm **3) The 100mm focuser height is the height from the top of the focuser to the outside of the tube when when it's racked out enough for the focuser tube not to be in front of the primary. The 27mm spare in travel is how much I can focus in from this position. By entering these new values to the calculator it tells me the Mirror Face to Focuser Hole distance should be 35mm shorter. It's also flagging some vignetting but this is due to the slightly over sized secondary as I wanted to prioritise better illumination of a larger sensor. This scope isn't meant for visual observations really. I've never done a mod like this before so I would appreciate if someone could take a look at these values / calculations and let me know if there's anything fundamentally wrong before I start drilling holes on the tube. I drew a template in LibreCAD to see what the new holes would look like. To be able to bring the focuser and the secondary spider vanes down 35mm I'd have to turn everything inside the tube 60 degrees:

Apologies for the delay. I've still been in full testing and developing mode as I ran into some issues. I attached my heaviest imaging train onto the NEMA 17 version focuser and pointed the scope straight up and found that it wasn't able to lift the weight up when acceleration was used. With acceleration turned off it works ok. I also finished assembling the NEMA 11 version and installed it on the Baader Diamond Steeltrack focuser. Initially the auto homing worked okay with it but after a while the focuser mechanism started slipping when it racked it fully in. This is due to the fact that I have a pretty high gear ratio with the timing belt attached to the fine tune side of the focuser. Was practically impossible to have the stall detection sensitive enough. I don't think it would work with a normal crayford focuser at all. So with these in mind I implemented a way to turn the acceleration and autohoming on and off from the INDI driver along with the ability to invert the motor direction. The device now also measures and reports the input voltage to the driver. Another annoying issue I ran into was due to the cheap Arduino Nano clones I'm using. They use CH341 serial communication chips instead of FTDI chips the original have. The CH341 chips don't report unique serial numbers to the host. Just a vendor and product Id which are the same for all of the chips. This means that there's no easy way distinguish multiple cheapduinos from each other using basic UDEV rules and I have a few of them on my system. To mitigate this I coded a python script gets triggered by the UDEV mechanism on connection and communicates with the devices to find out what they actually are and then creates unique and identifiable symlinks to the ttyUSB ports. I still haven't used these focusers for real yet but I'm sure I'll be ready when the next clear skies arrive. Again, apologies it's taken so long. I'll get there eventually

Does it not matter if the laser and the screen are not perfectly parallel?

Short answer is yes... Eventually...I've already started documenting my code. Will take some time to get it cleaned up and ready to publish. Not quite sure where to put everything though as I don't have a web site any more. Maybe GitLab...

Finally got this thing together physically. Had to reprint the enclosure to make some more space for the wires etc. I also had to ditch the idea of using the PT100 sensor I intended due to not being able to read it accurately enough with just a voltage divider using a precision resistor. The resolution of the analogue reads would have not been enough and I didn't have space inside the enclosure for a dedicated RTD to digital converter such as the MAX31865. Instead I decided to use the DS18B20 sensor which can be read with the OneWire and DallasTemperature libraries. I've now also got the INDI driver in a decent state so I can call this whole thing as Alpha. I'm sure there will be some unexpected bugs but I believe it's stable enough to start field testing. I'm planning to document and publish this as open source / hardware at some point. Just need to figure out how as I don't have a website any more. Here's the whole thing assembled and installed: The DS18B20 based temperature sensor inside a 3D printed enclosure along with an M4 screw so it can be bolted directly onto the focuser. The temperature sensor exposed. I decided to solder the few odd pieces of resistors and capacitors directly onto the Arduino along with the wiring. The TMC2209 silent step stick with a heat sink and a 100uF cap. With some gentle persuasion everything fits nicely inside the enclosure. Here's what the main control page of the INDI driver looks like in KStars. Here are the settings I've currently exposed to the user: Can't wait to start testing this under clear skies!

Hi, I'm not much of a visual observer but I do occasionally use my grandad's old binos I inherited from him. They must be over 30 years old and seem to be in fairly good condition. I do suffer from a bit of astigmatism in my eyes so I always find it a bit hard to focus with them. There is a separate "focuser" for the right eye so what I usually do I use the main focus lever to focus the left eye, then adjust the right eye after. Is that how you're supposed to do it? I haven't tried using them with my glasses yet. Anyway. I am curious if anyone can tell me anything about these binos. How good or bad they used to be. Would I benefit anything by getting a pair of more modern binos?

Finally I've had some time to mess about the arduino code for this focuser. Took a bit of trial and error plus some black magic voodoo to get the auto homing dialled in but it is working fairly well now. What it does is upon powerup it will rack the focuser out as far as it can. Once it reaches the mechanical limit the TMC2209 stall guard will indicate an error. From there it will rack the focuser back in to the other extreme while measuring the length of the travel. Once it reaches the inward mechanical limit it'll back out a tiny bit and call that home or the zero position. Here's a little demo of it:

Been trying to source a Baader Diamond Steeltrack focuser for my Newt for over 9 months and now I finally got one as it was back in stock for a brief moment at FLO. Turns out my first NEMA 11 version of my DIY autofocuser is perfect for this. Just had to design and print a new bracket and get a HTD 3M pulley and belt. Work is keeping me too busy from writing the arduino code and indi driver though. Only should have to do it once though as the electronics on these two are pretty much the same.

The new stepper arrived today and does seem to do the job well even at 32 microsteps. I had this test running for several minutes and the dial gauge always stopped at the same spots. Feels like this will work nicely now!

Did a bit more pondering and experimenting with this. The rated torque of the stepper motor in the above video is supposed to be 26Ncm which feels just about enough with the 16th microsteps I was running it with (AFAIR). But it didn't take much resistance by hand for it to start skipping steps which was a bit of a bummer. Just as an experiment I also tried with another NEMA17 motor that was rated about 19.8Ncm. This wasn't enough to move the focuser without helping it by hand at all so I guess I'm just above the threshold with the 26Ncm motor. I'm currently waiting for a delivery for yet another NEMA17 motor that is supposed to be rated 45Ncm. I'm hoping that will be enough to drive the focuser at 32 microsteps. That's the sort of resolution I'm aiming for minimum without any sort of transmission. One microstep would be around 33 microns of travel while my worst case scenario critical focus zone is just above 50 microns. Hope it works out okay. If not then I'll have to look into a geared stepper or a pulley and belt system. Feels a bit like I'm balancing on the edge of failure at the moment...

Gave a NEMA 17 stepper a go and it's much better. Think I will go with it and re-design the enclosure around it. Here's a quick test:

This is the first time I'm using a TMC2209 driver and the TMCStepper Arduino library so I'm not too familiar with it yet. I'm trying to configure it via the UART interface which gives me loads of options but in regards microstepping I haven't been able to really go below 8 microsteps as it seems to start misbehaving even without any load. So far I've had the best results with 16 or 32 microsteps. I know in theory I should get more torque with native steps but I'm not sure if that's the case with the TMC2209.

Had another look at the specs of the motor I have and it's rated 0.67A @ 6.2V so I'm already nearly double the voltage driving it with 12V. Increased the current going into it as much as I dared and it did start moving the focuser but it was occasionally skipping steps and got rather hot too. Think I'll try a NEMA 17 stepper which I already have to see if it's better. Just need to print a new L-Bracket for it.

Ouch. Ran into a bit of a road block with this. Turns out my chosen NEMA 11 12Ncm motor is not quite strong enough to drive the focuser attached directly on the (coarse side) of the focuser shaft. It very nearly works with a bit of help by hand but not on its own. Not even with some over current and slow acceleration etc... Bummer... So back to drawing board. A few options I can think of include: Use a bigger and stronger stepper (NEMA 17 for example) the same way on the coarse side of the focuser shaft. Use the existing NEMA 11 stepper on the 10:1 side of the focuser and deal with backlash in the arduino code. Use the existing NEMA 11 stepper with pulleys and a belt to gain better gear ratio while minimising backlash on the coarse side of the focuser. Use a NEMA 11 stepper with a gearbox on it to gain more torque on the coarse side of the focuser and deal with backlash in the arduino code. Any other practical ideas you guys can think of?

Had some issues with the focuser of my nearly new FLT 91. I think I got it working properly now. Wrote a google doc about it: https://tinyurl.com/jzh8n85x

Decided to make another DIY electronic focuser for my new WO FLT 91. It will be Arduino Nano based again but this time I'll be using a Trinamic TMC2209 based stepper driver (Same as in my Prusa Mk3). The focuser on the scope is a rack and pinion style and I'll be driving it with a flexible coupler directly on the focuser shaft. I'm hoping to utilise the Stall Guard feature of the TMC2209 to auto-home the focuser and also as sensorless limit switch. I'll be adding a Class A PT100 based RTD as well to measure the focuser temperature. I found one with M4 thread that I can bolt directly on the focuser body. I've pretty much done with the mechanical design. Still need to finalise the electronics and solder it together + write the firmware and INDI driver.