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Hi all, I recently bought an ASI Air Pro. Below is my gear for reference. I have been out imaging about 4 times with it and it has all gone quite smoothly except for the guiding. Before the ASI Air, I had so many nights where everything went amazingly with the guiding via the computer being under 0.5". When I now use the ASI Air, the lowest I can manage is about 1.75" for an extended period of time. It sometimes dips below 1" but only for about 15s. I have tried copying the exact settings from PHD2 to the ASI Air (Calibration Steps (ms): 1250, Ra Aggressiveness: 70%, Dec Aggressiveness: 100%). I then use between 0.5-1s exposure for the guide camera. When I do all that, it goes ecstatic and guides like crazy. Unfortunatley I don't have any screenshots of the actual guiding but I can get them on the next clear night. Any ideas to fix this? guide scope is focused, the mount is polar aligned below 1'. Mount is balanced as well. Skywatcher AZEQ5 SVBONY 50mm Guide Scope ASI120MM 1600MM Sharpstar AL-90R EAF EFW ASI Air |
3.31
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Lachlan, Not sure what your issue is but when I was struggling with similar issue I did find out that the ASI saves a PHD guide log in the log folder that you can view with the PHD log viewer (separate download). Access to that helped me fix my problems! hope that is of some use. john |
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3.31
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Having said that when I guide with my 50 mm guide scope and Z61 I use 3 s exposures 1s might be too fast. The other thing is to just redo the calibration and make sure it runs full cycle. The ASI AIR can look like it’s calibrated even if something went wrong. John |
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1.91
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Hi John, Did you then just compare the guiding logs from the ASi Air with the PHD2 logs? I tried every exposure that was available last night. The stability increased as I lowered the exposures until 0.5s and then it lost the guide start. When I used a laptop to guide, I use between 0.5 and 1s as well and it gave me splendid results |
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1.91
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        Here are a couple of different times I tried different settings for the guiding. I'll attach the .txt file if you want a further look PHD2_GuideLog_2022-03-19_201942.txt |
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3.31
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Wow your right those are crazy results - I can only say when I’ve had issues it’s never been the ASI. How are you connecting to the mount ST4 or USB? Perhaps try image capture with the ASI and guiding with your PC just to see! I see this is over 4 nights so this probably isn’t relevant the only things that do this for me are high clouds and calibration. To your question I’ve never used PHD only the ASI - I just found the logs really useful. John |
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1.91
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These are all over the same night. Spent like an hour trying to get the guiding right. Even re polar aligned. Turns out I was 12' off the first time. I connect to the mount via a USB cable to guide and control the mount. Next clear night I will try with just my laptop and if all goes well, I might even try with the ST4 cable. Thanks for the info on the log viewer. Very useful. |
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3.31
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| What about guiding rate sometimes the ASI asks you to confirm but sometimes it doesn't - CGME does iOptron doesn't. Double check your not guiding at slew rate. |
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| Try reducing your aggressiveness , I rarely use 100% , usually down at the other end between 5 and 50 % |
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1.91
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John, Guiding rate I bounced between 0.25 and 0.5. 0.5 is the default on PHD2 but 0.25 is the default on ASI Air Henri, I shall try that! Thanks for the info |
13.23
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| If seeing is not great (twinkling stars) I use 2 to even 4 second exposure. You don't want to be chasing star movement due to the seeing. 50mm guide scope on at 1600mm tube is not a great ratio. John Noble's suggestion is a good one...guide rate. |
7.67
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A few things to try: Try keeping the calibration step at, I dunno, 2500ms to 4000ms. I base this on your guide scope's focal length. (The longer the guide scope FL, the shorter the calibration step.) The max DEC and RA duration I'd do like 2500ms but you can step it down to 1000 - 1500ms if its windy out. (If you had an OAG you could go as low as 500ms.) For the guiding rate, I've read that the lower settings are better for higher end mounts with quality gear systems with a capital Q. For reference, on my CEM40 and GEM28 I alternate between 0.75x and 0.90x. I still haven't nailed it down. For the aggression settings start at 50 and start experimenting with 5-10% increments either way. One second guiding exposures are basically for god-tier seeing, and you'll usually end up using between 2 and 4 seconds. Following these usually nets me around 0.4 to 0.8 on the CEM40 and 0.5 to 1.2 on the GEM28. I blame stiction for the crazy variation on the GEM28 but whatever. Given that the fellas above have already mentioned most of this stuff, allow me to suggest checking if the permanent periodic error correction on your mount is enabled, because the ASIAIR does not play nice with it. If it's on, ya gotta turn it off. In addition, when running the ASIAIR, it's best if you can do it without the hand controller even plugged in to the mount if possible. |
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John Favalessa: Sorry John, I've made a misunderstanding. I am using an ASI1600MM Pro. My telescope is only 600mm focal length. |
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13.23
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| clearly that now makes sense to me. Keep us up to date with your struggles. I'm running a beta test version of the ASIAIR software so comparing my results with yours may not be valid. I can say that lately (like for 2 months) seeing has been terrible at home and mostly cloudy at my dark site (Mt Pinos). At home, my average total RMS lately is ~0.9+ When conditions are good ~0.6. At my dark site ~0.4 to 0.25. I figure seeing is a big part of our guiding. |
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| Will do John. It managed to clear up last night, wasn't amazing seeing though. All your suggestions dropped the average over the night from about 2.5' down to a very nice 1.3 average. I think with better seeing and the actual drive to take an image instead of just getting stuff working, I should be work it out. |
15.65
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Glad to see you’re getting it under control. Another tweak (if you haven’t done it) is to make sure your guide FL is correct in the AIR. Set the guide cam as the main cam and do a plate solve and the AIR will tell you the exact FL it thinks it is. Not sure if it makes any difference, but we are talking a certain amount of voodoo here. And remember it is really about the images. Slightly higher guide numbers may make no difference in your pictures. |
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Will do thanks! I did try that the last night I struggled before I came on here. It wasn't able to plate solve at all. Should be about 194mm. Maybe the guide scope was so far out of focus. And you very right about the guide numbers. Except when the guiding is so bad it creates trails all the way across the image 🤣🤣 |
10.16
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Hi Lachlan, In the last days I have similar problems as you: platesolving often does not work and guiding is horrible. Usually my telescope runs at 0.5 to 0.7, currently it knocks out to 4 or 5. The search for the error has shown that light wind gusts are to blame. They are hardly noticeable on the skin, but it is enough to move the telescope a little. This turns the stars into dashes for the guiding camera, and the main camera paints funny streak patterns. My attempted solution: I expose shorter than usual. This way I get at least some usable subs. Maybe you also have a wind problem. Good luck and clear skies! Olaf |
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13.23
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| I had the best guiding all winter (but now spring) from my backyard last night. 0.5 to 0.8 total RMS. I have changed nothing, same great polar alignment and balance, same auto focusing, same rig with OAG. It's just got to be better seeing. It is interesting to me how much environment influences. I did build a wind baffle and light pollution structure out of PVC and custom tarps from tarpsnow.com I learned the hard way to use the heavy duty PVC here with So Cal winds. here's a pic...I was running two rigs, one's inside. https://www.astrobin.com/6psk63/ |
