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RugbyRene
24-01-2021, 08:28 AM
Hi all,

Well last nights session was yet another in a long lines of wasted nights of imaging. My guiding has never worked properly. A good nights guiding is getting an RMS of 1.9. I polar align, I balance I tweak settings ad nothing seems to work. I'm at the point where I either find a solution and get my guiding under control or I give the whole thing away.

But before I launch into an explanation of my issues I'll describe my equipment & set-up routine:

Equipment

Mount - SW AZEQ6
Main Scope - SW Esprit 100
Main Camera - ASI1600 or 294
Guide Scope - SW Evoguide 50 (242mm focal length)
Guide Camera - ASI120mm mini
Software - KStars/Ekos running on a RPI4
Guide Software - Internal guider within KStars (though I have tried PHD2 without success


Setup
My nightly routine is as follows:

Setup tripod and level
Load up all of my equipment and balance. I balance in DEC first and then in RA (as per Dylan O'Donnell's advice). I find balancing on the AZEQ6 to be a pain as the clutches are quite stiff.
Once balancing is done I fire up KStars and PA using the internal PA routine.
I then do a star alignment so the mount knows where it is (don't we have GPS for this?)
Then slew to my intended target and plate solve.


So far so easy but this is when it starts to all fall apart.

I start my guiding calibration using the internal guider in KStars. I've tried PHD2 but can never get it to work and I figure why use yet another piece of software when KStars does it all.

Yes I know others swear by PHD but I can't get it to work.

After guiding calibration, the mount starts to guide. It's a bit wonky at first so I always let it settle down for a few mins.

DEC is never the problem. My DEC RMS is always around 0.5. It's RA that's the problem but overall my guiding graph is horrible and regularly hangs around 1.8-2.5 RMS. Over the last few nights I've seen some weird things happening. Here's a list of some of the weirdness:


On a good night I can get 0.8-0.9 RMS...........for about 2 mins. The mount will guide nicely, I'll have a nice smooth graph and then seemingly out of nowhere the RA graph goes crazy and my Total RMS will go to 1, then 2, then 3 then 4 then off the scale and not recover.

Guiding will start off bad and never get good. My usual night is starting with and RMS of 2.5 and it never getting any better

Guiding will start and the plot graph will be all over the place. Total RMS will be off the chart and the only thing I can do is stop it and do a recalibration.


So I'm at my wits end and as I said, I'm at the point of giving it all away as I'm fed up wasting hours (not to mention sleep) trying to fix this. I'm hoping the community can help me diagnose my issues. I'm starting to think it's an issue with RA in the mount. Perhaps the worm gear, belt drive or a combination of those and something else.

Yes I realise there's periodic error in RA on most mounts and I've not done PE training yet but will. Though periodic error can't explain some of the weird things I'm seeing like the mount suddenly flying off in RA for no apparently reason or having good guiding then it getting progressively worse and worse.

Thanks in advance for any help you can provide.

Rene

Startrek
24-01-2021, 08:37 AM
I feel your pain
Sounds like you have a good understanding of guiding
Bad guiding can only be caused by human error , machine error , connectivity or atmospheric conditions
My only advice is get your mount serviced and tuned properly then go from there
There’s a company in WA that does it but no sure of the name

Maybe others can pitch in and help

Good luck !!

RugbyRene
24-01-2021, 08:40 AM
I'm taking it in to get serviced by Bintel, so hopefully that will help.

Rene

multiweb
24-01-2021, 10:28 AM
Good idea. It sounds like your mount RA needs a bit of cleaning or tuning but it's likely mechanical. I can't see the software doing this.

mswhin63
26-01-2021, 12:09 AM
At this stage, I am using Astroberry with RPi 4 8G model also I never had much luck with the internal guider. I am though having good success with PHD2, even running multi star guiding as well which works really good.

If you lived in SA, would be glad to have a look. Good luck with it all. I am not much into paid software as i prefer to nut out issues myself. I learn a lot from it. Stellarmate is good for non technical people,although if there is a bug, I do not know how long it takes to get the support.

RugbyRene
26-01-2021, 08:14 AM
Thanks Malcolm,

Seems the consensus is to give PHD2 another try. Once my mount is back from Bintel I’ll try it out and see if I can get it working.

Rene

Sunfish
26-01-2021, 11:08 AM
I agree with the mechanical issues in RA. Seems typical that the RA runs off if the mount needs tightening and servicing due to backlash and loose worm gears. Particularly in the Zenith and the East. Also recalibration helps with each slight change or over- large guiding corrections.

Servicing my mount and replacing bearings and belts made a big difference. I also use PHD as the external guide system in Kstars on several devices and it works well if everything is set up in the right order. With the advantage that you can use PHD in other capture programs also.

RugbyRene
30-01-2021, 09:13 AM
So I want to try pulse guiding (I’m using the ST4 cable atm) but would like someone to explain how I setup the cables. I know I can ditch the ST4 cable but am unsure where I connect the guide camera. Do I connect it to the guide camera to the main camera or to the mini PC?

Rene

Startrek
30-01-2021, 09:25 AM
ST4 guiding will not solve your guiding issues, plus it in inferior to Ascom pulse guiding for many reasons , one is you have to calibrate every time you go out imaging , this waists time
The PHD2 developers do not recommend ST4 guiding, they recommend Ascom pulse guiding
Believe me stick with Ascom pulse guiding, once your mounts issues are resolved you will be up and running
Most folk would agree
Cheers

RugbyRene
30-01-2021, 09:33 AM
Yeah I want to move from ST4 to pulse guiding but need to know how the cables are to setup.

Rene

Startrek
30-01-2021, 09:49 AM
Ascom Pulse guiding just requires a USB cable from guide camera direct to laptop ( USB2 or USB3 depending on your guide cameras connection )
Warning do not use a ZWOASI120MM USB2 camera as they have an inherent problem ( I know I went through hell for 2 months trying to get it to work on PHD2 ) use the ZWOASI120MM-S USB3 camera , no issues or a similar camera
You should already have the mount connected to your laptop using some type of mount control like EQMOD or other
Download latest Ascom drivers for guide camera and your mount control
Set up and connect PHD2 and your done
Here’s some more information attached
Hope this helps

RugbyRene
30-01-2021, 10:52 AM
Cheers for the info. I have a ZWOASI290MM Mini. Does that have the same issues as the 120?

Can I connect the guide camera to the USB hub on the main imaging camera?

Rene

Startrek
30-01-2021, 11:07 AM
If you’ve read my attached notes it mentions to connect guide camera direct to laptop ( preferable) and try to avoid going through hubs and the like. But you can only try going through a hub as long as it’s a powered hub ( active ) not a passive hub ( unpowered) You have to eliminate any possible glitches with getting your PHD2 guiding up and running and hubs are just another weak link in a long chain of spurious issues that can present themselves. Personally I would cable direct to laptop, which is what I did and no issues in over 3 years of use
As far as the ASI290MM guide camera I haven’t come across any issues reading the various forums. It is USB2C connection on the camera end so try to keep your cable length 5m or less from guide camera to laptop

The_bluester
30-01-2021, 01:45 PM
I have been using a 290mm mini via the hub on my ASI294 main camera for about two years without major issues. It refused to connect once which turned out to be a bit of tracking through built up grime in the connector on the camera (The 290) which is not completely unexpected for a connection on top of the camera that is used out in the damp night air. A burst of isopropyl alcohol and a scrub with a short bristled paint brush saw that fixed.

RugbyRene
30-01-2021, 02:39 PM
Thanks Paul. That gives me confidence that it should work. I've got a 294 & 1600 so hopefully I don't encounter any issues.

Rene

Craig_
30-01-2021, 04:56 PM
Curious to hear what impact the mount servicing has on fixing your problem - do report back when you can! Is Bintel doing it under warranty (if you bought from them) or as a paid service?

RugbyRene
31-01-2021, 07:08 AM
Definitely not under warranty.:rofl:

I’ll report back but it might be a while. I was there mid-last week to pick up a camera and asked when would be a good time to drop it off and was told mid-Feb as Don is snowed under. The pandemic has meant people have gotten their gear out of storage and getting it serviced.

Rene