Getting the best performance from my AM5: Page 25

Getting the best performance from my AM5

CHriss

btw, what's the opinion on PHD2's DEC backlash compensation with the AM5?
On or off?

MrAstro

CHriss
I never used backlash compensate with my AM5 and PHD2.
Also, in PHD2 when you tick "fast recenter after calibration or dither" it will ignore the Max duration to recover faster.

Jan75

I have now tried using a guidescope rather than OAG and even 0.2s guiding exposure (instead of 0.5s) and a counterweight. To no avail: the total RMS is still mostly in the 0.9"-1.1" area including on targets such as M57 that have high declination. Frequency analysis shows strong Nth-order peaks with the dominant 2.9s-period one reaching above 1". I just sent my latest PHD2 log to ZWO, now waiting for any response but right now I think I have pretty much exhausted all configurable parameters.

Jan75

Kevin_A

I am noticing that when I look at the guiding graph in asiair, that while guiding is acceptable, there is very little small guide pulses to keep it in check and it only seems to have a few large pulses when my graph gets spikes? Anyone else notice this? Guiding generally is in the 0.4 to 0.8 range but no corrections in either axis are issued unless a 1s spike occurs. Maybe asiair just is not showing smaller pulse corrections?

w7ay

Kevin_A it only seems to have a few large pulses when my graph gets spikes?

OK, we are finally getting down to the gist of it all.

Did you see an especially large guide pulse before the large guide graph deviation?

If you are seeing large number of pulses before the guide graph has gone, up, PHD2 is doing something weird (issuing guide pulses without any stimulus).

However, if you are seeing large number of pulses after the guide graph has gone up, this is "normal." However, you need to investigate it the rise in the guide graph is cause by (1) wind (I see the effect of even 3 mph gusts (measured on NetAtmo 15 feet away from the tri-pier); but the graph would deviate for a couple of seconds, and settle back), or (2) by centroid estimation error (i.e., the guide scope "lying" to PHD2 that the sky has moved even though it has not), or (3) by the mount' mechanism not being able to keep sub-arc-second precision.

(1) and (2) are likely to affect both axis at the same time. (3) tends to happen to just one axis at a time. So that could be a clue.

I was just going through 6 mph wind gusts last night, and autoguiding deteriorated to the 0.5" range from the 0.35" range the night before, when the gusts peaked at no more than 2 mph.

Chen

Kevin_A

w7ay the pulses in log viewer are there and happen right at the middle of the peak so it is working it seems… they are just not being shown on the asiair graph. I did find out why 2 of my older asiair pros are crappy… their minmo is 0.2 vs my asiair plus at 0.1. Same firmware update.
Weird but now I know why 2 rigs are good and 2 are bad.

Kevin_A

Revised: I had noticed that when I look at the guiding graph in asiair, that while guiding is acceptable, there is very little small guide pulses to keep it in check and it only seemed to have a few large pulses when my graph gets spikes? Guiding generally is in the 0.4 to 0.8 range but no corrections in either axis are issued unless a 1s spike occurs but asiair just is not showing smaller pulse corrections it seems. Actually in phd2 log viewer they are there… just not in asiair app. Another thing I just noticed is in the latest firmware 10.74 for asiair plus the minmo is 0.1 but in the same firmware version for the older asiair pro it is 0.2. No wonder my 2 older asiair pro guide much worse on my am5.

Zwo can you fix this as my guiding is 50% worse on my asiair pro setups using a minmo of 0.2.

w7ay

Kevin_A their minmo is 0.2

Yep, that will definitely be one huge step back. Not problem for me, but for people stuck with using ASIAIR (their own choice, so you can't really blame ZWO).

Chen

Kevin_A

w7ay I guess I could go back to using phd2 but I think I prefer imaging wirelessly from my couch. Haha. But when I build another house with a real observatory then I will go back to where I can decide and use my own settings. Winter is coming soon and I just can’t do cold anymore!
I hope they fix their errors in the next update. I moved both asiair pro units to my widefield scopes so higher guiding numbers are less critical . I did try an OAG on my Askar FRA300 and since the scope delivers crisp stars at F5 and with my 533mc pro having a tiny sensor, i could get it deep towards the centre… it worked quite well when I pumped up the gain. I imaged all night at 0.5rms and under.
Star quality definitely matters with this ecosystem.

w7ay

Kevin_A I guess I could go back to using phd2 but I think I prefer imaging wirelessly from my couch.

You can do the same using this with a Raspberry Pi 4 (guess how I know :-):

https://www.indigo-astronomy.org/indigo-sky.html

From indoors, you can do rudimentary stuff (planetarium, mount control, camera control/scheduling, PHD2 guiding) just from any web browser (including on tablets), or use a full blown laptop on your couch with full blown components:

https://www.indigo-astronomy.org/software.html

The components are all packaged as a turn-key INDIGO "All-in-one" A1 if you are lucky enough to own a Mac:

https://apps.apple.com/us/app/indigo-a1/id1617125771?mt=12
https://www.cloudmakers.eu/a1/

The second link has videos to how to do things like polar alignment, etc.

(Notice that it collects no user data. Even if it does, it would go to a NATO and EU country, instead of to China.)

If you prefer YouTube (comic book) documentation, Rumen Bogdanovski (one of the two principals) even has a YouTube video:

https://www.youtube.com/watch?v=ko1Qjs9Zdes

Rumen [https://bg.linkedin.com/in/rumenbogdanovski] owns one of the earliest AM5, by the way. Peter Polakovic, the other principal, is a MacOS nut -- he ordered his M1 Mac even before I did :-) For day work, one of them is an astrophysicist, and the other is a computer IT professional.

Best of all, you can use better cameras, filter wheels, and image rotators than you can on an ASIAIR.

Even better for a geek, since the INDIGO bus is completely open sourced, and documented (in fact, the only place I even found the documentation of communication protocol for the ZWO mounts was in INDIGO's documentation), you can add any of your own software (that is how I run my All-Sky camera nowadays, though a Raspberry Pi 4, and my own macOS program, using a no-longer used ASI294MC).

https://github.com/indigo-astronomy/indigo

Everything looks like devices on a networked bus. Add as many servers as you want to the bus, and access them from multiple clients.

I have already 12-volt-modified a M1 Mac Mini (retired it as a desktop computer when I replaced it by the Mac Studio) to use as my outdoor server. Even if you buy an M1 Mini new from Apple, you can get it for $600, and it is orders of magnitude faster than an ASIAIR.

So, you can go from just a single Raspberry Pi 4 and a tablet running a web browser, to a serious system where the sky is the limit. The upgrade path is already there today. Just add more processing power (more microcomputers, or simply a faster microcomputer) when you feel the need. (Oh, INDIGO can run any device that is supported by INDI -- you can even find humidity sensors. :-) All of your current ZWO devices will still work: I have tested ZWO EFW, EAF, cameras, etc. Just get a Raspberry Pi 4, download and burn an microSD IndigoSky Image, and start playing from just a web browser.

Chen

Jan75

Kevin_A Or just use remote desktop? I'm thinking of moving to a laptop based system too, just for the increased array of options in NINA/PHD2 vs. Asiair GUI.

Kevin_A

w7ay I will keep it simple for now as i am getting consistant 0.5rms now that I tweaked a few things and put some better feet on my tc40 tripod, bigger guide scope, bumped up gain etc… but I think that is the best this mount can do and I am fine with that. It will never be an RST and as long as zwo stop making bonehead moves like increasing minmo for us strainwave dudes… then I will keep it simple for now. I just need the next update to reduce the minmo of the asiair pro for my older setups and add am5 guide rate adjustability and I will be happy.
Cheers,
Kevin

Jan75

w7ay Awesome links, thank you. I was getting desperate after multiple unsuccessful attempts to make my gear work with a Linux laptop and just tried INDIGO today - it works!

For everyone, here's a very interesting article written by the authors of INDIGO, featuring the ZWO AM5:
https://github.com/indigo-astronomy/indigo/blob/master/indigo_docs/GUIDING_MISCONCEPTIONS.md

Jan75

Also, one note, some progress on my side too. When I use BIN=1x1 on the guide cam (instead of the previously used BIN=2x2), the guiding results are in the realm of 0.4"-0.6" instead of 0.8"-1.0"+

This is true both with a guide scope (60mm, 254mm FL, ASI ZWO 120MM) and with an OAG (ASI ZWO 220MM mini).

Also, ZWO recommended that I open the AM5 case and check the belt tension; they asked me to adjust it by pushing the RA motor away to fasten the belt. I didn't do this because the method is quite rudimentary (unscrew, push, tighten - no easy way to measure the adjust movement)) and has no easy fallback.

With 1x1 binning the performance is OK for my FL (1628 mm) so I think I'll just stick with it for now.

BrineyEye

I don't know if I will accomplish anything by posting this, but I have recently seen the same large RA oscillations in my AM5. Autorun (on M27) is where it cropped up. In complete desperation I went back to Preview and forced a calibration, and it stopped. This may have been a coincidence, but I thought that I would add the data point. I assume that there is a subtle (or not-so-subtle :/ ) bug in the guiding routine or the mount firmware.
I've had the AM5 for almost a year now, and other than this recent development I've been completely satisfied with it.

-Jon

ASIMount@ZWO

BrineyEye Would you please contact our support and provide your guiding log. It would help us to deal with your issuse. Thank you.

Jan75

BrineyEye and ASIMount@ZWO The guiding with ASIAIR appears to be sub-optimal to me because of the number of stars ASIAIR chooses to use for guiding. While I can visually see a number of stars, ASIAIR typically picks only 1 or 2, or starts by picking 5-6 then a few minutes later it's down to 1-2 again. With the AM5 requiring fast corrections, e.g. 0.5 s guide exposures, this means that you're chasing the seeing instead of correcting the mount tracking errors. Averaging the centroids over 10+ stars would more or less compensate for the seeing induced movements of every individual star. I've been having the hardest time trying to keep ASIAIR track more than 2 stars. This is where you can go from 0.4-0.6" guiding to 1.2"+ guiding with the same mount...

KC_Astro_Mutt

Jan75 this isn't likely a function of the ASIAir. More than likely, it's the camera. I use an ASI178MM, and consistently get 10 to 12 guide stars on the Air. I also have an ASI290MM that gets about the same. My old 120MM would barely get 3 to 5.

Prusling

I agree about the camera - I upgraded to an ASI220MM and there was a significant difference. I also found that a larger aperture guidescope helps - I went from a WO 32mm to WO 50mm and saw a further improvement.

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