Guiding calibration failed - star did not move enough...

[Delboy_Hog]

Hi folks,

How do I get the star to move enough?! And how much is enough?

This is the message I'm getting using an ASIair (the older version, but fully updated software I think) on the Star Adventurer, with an ASI 120mini finder-guider. The star is moving a little bit, but never more than dist = 5 or thereabouts, and after 60ish steps it stops trying.

I've tried bumping up the calibration step amount from 500 in various intervals up to 10,000, no luck.

Any ideas? I'm at a total loss. Have tried numerous different stars, balanced the mount perfectly and tried unbalancing it a little just in case, locking the mount down more and less in case I had it too tight / loose...

The mount appears to be working fine on normal tracking mode, but hoping to get the guiding working to get those longer subs....

Any ideas would be hugely appreciated!

Derek

[newbie alert]

Assuming the mount can take guide pulses? I know people do guide with the SA but I'm not sure on how it works.. you need to turn DEC guiding off as it hasn't got that axis,so maybe it's trying to send pulses in Dec and it's not moving 

[MarkAR]

Usually I get the same message when using Ekos, it's picked a hot pixel as a guide star. Try to pick another manually.

[gilesco]

10 minutes ago, MarkAR said:

Usually I get the same message when using Ekos, it's picked a hot pixel as a guide star. Try to pick another manually.

Sometimes I get this if I have set guiding via the ST4 cable, which is not connected, rather than directly to the mount.

[Delboy_Hog]

15 hours ago, newbie alert said:

Assuming the mount can take guide pulses? I know people do guide with the SA but I'm not sure on how it works.. you need to turn DEC guiding off as it hasn't got that axis,so maybe it's trying to send pulses in Dec and it's not moving 

Thanks for your thoughts, Newbie!  I think it can?  It does move slightly when the calibration starts, but they just don't seem very strong or consistent, so it'll move to 0.3 at the first step, 0.5 at the second, then go back to 0.2, then go up to 0.7, then back to 0.5 and so on, so it gradually creeps up, just not enough to reach a point that satisfies the software.  I've tested the buttons that drive the mount (on the side of the SA) and they seem to work okay (and if you press them while it's doing the calibration, it registers as a many-pixel movement, as you'd expect).

And yes, I have the DEC guiding switched to off, though I really appreciate the sense-check - I'm sure there'll be a setting like this that I've missed somewhere!

This one is really puzzling me!

[Delboy_Hog]

15 hours ago, MarkAR said:

Usually I get the same message when using Ekos, it's picked a hot pixel as a guide star. Try to pick another manually.

Thanks MarkAR, definitely checked that one - picking stars manually that blur etc with guide-cam focus change and that blur and move when I nudge the mount!

[Delboy_Hog]

15 hours ago, gilesco said:

Sometimes I get this if I have set guiding via the ST4 cable, which is not connected, rather than directly to the mount.

Hi Gilesco,

Could I check what you mean when you say 'directly to the mount'?  I've been relying on the ST4 cable from ASI-air to the mount (and did check it was plugged in!), but haven't clocked a setting I could change to suggest a different way - have I made a ridiculously rookie error and there's something else I should be doing?!

Thanks for your thoughts!

[newbie alert]

12 minutes ago, Delboy_Hog said:

Thanks for your thoughts, Newbie!  I think it can?  It does move slightly when the calibration starts, but they just don't seem very strong or consistent, so it'll move to 0.3 at the first step, 0.5 at the second, then go back to 0.2, then go up to 0.7, then back to 0.5 and so on, so it gradually creeps up, just not enough to reach a point that satisfies the software.  I've tested the buttons that drive the mount (on the side of the SA) and they seem to work okay (and if you press them while it's doing the calibration, it registers as a many-pixel movement, as you'd expect).

And yes, I have the DEC guiding switched to off, though I really appreciate the sense-check - I'm sure there'll be a setting like this that I've missed somewhere!

This one is really puzzling me!

I've just thought of someone that guides with a SA, I ask the question for you

[gilesco]

17 minutes ago, Delboy_Hog said:

Hi Gilesco,

Could I check what you mean when you say 'directly to the mount'?  I've been relying on the ST4 cable from ASI-air to the mount (and did check it was plugged in!), but haven't clocked a setting I could change to suggest a different way - have I made a ridiculously rookie error and there's something else I should be doing?!

Thanks for your thoughts!

Well when using Ekos for guiding, you can either guide via the Guide Cam (i.e. via the ST4 cable that connects from the Guide camera to the Autoguider port on your mount), or you can get Ekos to directly talk to the mount via the Handset connection (I have a CGX). I don't bother connecting the ST4 cable and usually set Ekos to guide via the Telescope Mount. Of course sometimes I forget to set that up, and as the ST4 cable is not connected (in my case), then the pulse commands don't move the mount.

If you're using an SA then I think your only option is to guide via the ST4 cable.

Did I hear with PHD that there were multiple places to disable the Dec guiding??, perhaps have a look around the extra settings.

[Delboy_Hog]

9 hours ago, gilesco said:

Well when using Ekos for guiding, you can either guide via the Guide Cam (i.e. via the ST4 cable that connects from the Guide camera to the Autoguider port on your mount), or you can get Ekos to directly talk to the mount via the Handset connection (I have a CGX). I don't bother connecting the ST4 cable and usually set Ekos to guide via the Telescope Mount. Of course sometimes I forget to set that up, and as the ST4 cable is not connected (in my case), then the pulse commands don't move the mount.

If you're using an SA then I think your only option is to guide via the ST4 cable.

Did I hear with PHD that there were multiple places to disable the Dec guiding??, perhaps have a look around the extra settings.

Ah okay, that makes sense, and thank you for describing - yes I think the ST4 cable is the only option with the SA.

Hmmm, your point on the need to have multiple options set a particular way could well be the issue, and the ASI-air interface is (I'm told) very similar to PHD.  I'll have another scroll through the menus and see what I can find.

Thanks again!

[Delboy_Hog]

10 hours ago, newbie alert said:

I've just thought of someone that guides with a SA, I ask the question for you

Many thanks, that's very kind of you!

[Delboy_Hog]

Some other possibilities I've been pondering...

Mechanical: I've seen a couple of cases of this error message being (potentially) linked to 'backlash'.  I don't really understand this too well, though there are some references to some SAs being too "tight" and apparently there's a screw (or something) that can be loosened off to reduce this.  Does anyone know if the issue I described sounds like something that could be caused by strong backlash?  The distance the mount travels each step of calibration is small, and does seem to go back on itself occasionally, rather than smoothly and continuously moving away from the guide star....

Power to the mount: I'm currently using the 4 AA batteries rather than the DC 5v / USB approach.  The AAs are all a quarter to a half 'full' - I wonder if it's safe to assume that if the batteries can drive the mount when pushing the slew buttons, they have enough power to drive the mount via the guiding?  O should I be trying again with batteries at 100%....but then I would think that standard batteries maintain their function reasonable well through the second half of their lives?

Power to the ASI-air: I'm using a 5v 3.4a USB power bank - that should be more than enough to power the ASI-air (to avoid confusion, this is the old version, I gather the 'pro' has different power requirements) to do it's thing and to send pulses to the mount......right?!  I do have a 4a+ power bank somewhere that I could try, I guess, but can't imagine the Air pulling that much, especially as the power requirement to move the mount comes from the mount batteries, not the Air, on this version. 

Settings: I appear to be doing things differently from the various youtube tutorials I've found, in that I don't have the ASI-air connected to the DSLR, and just have the main camera set as 'none' and the telescope set as 'on-camera ST4'.  I can't imagine that not connecting to a main camera would impact on the guide camera's ability to calibrate though?  Unless as Gilesco mentioned, the settings might have to be a certain way...

Any and all thoughts / suggestions would be much appreciated!

[gilesco]

About power, not that I profess to know about electricity, but in my opinion I try to power from an AC / DC regulated power supply. Drawing power from batteries seems to raise issues for me, although I'm planning on getting the larger Skywatcher / Celestron power bank for dark sky site stuff... i would not power stuff from regular AA batteries, as I'm not sure whether the intermittent draw is provided quickly enough, and it is something that might change over a long session.

[Delboy_Hog]

10 hours ago, gilesco said:

About power, not that I profess to know about electricity, but in my opinion I try to power from an AC / DC regulated power supply. Drawing power from batteries seems to raise issues for me, although I'm planning on getting the larger Skywatcher / Celestron power bank for dark sky site stuff... i would not power stuff from regular AA batteries, as I'm not sure whether the intermittent draw is provided quickly enough, and it is something that might change over a long session.

Hmmm, yes I did wonder, as you say, especially with a long (and last night was cold too!) session.  It's clear-ish here tonight so I'll have another tinker with the kit and see if I can resolve this!

The desire to have a nice, portable, plug-and-play setup for taking to dark sky sites was one of the big motivations for me trying to get the SA up and running effectively, and going down the ASI-air / 120mm mini-guider route.  I have an old Celestron 7ah power tank which has served me very well over the years, and if I can figure out the right adaptor / regulator, may yet be the solution here!

Thanks again for your input on this.

[Hughsie]

I got this error when I forgot to turn on sidereal rate on EQMOD. Soon as switched on the tracking the error went away.