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[almcl]

Here's a little head scratcher that I have been having with my AstroEQ.

I have a couple of these in use on an EQ5 with stepper motors and very good they are too.  It's only used for widefield imaging with a Canon 200 mm prime lens and regularly guides at under 1 arc sec.

The issue lies somewhere between the AstroEQ and EQmod.  When first connected in my custom home position and asked to slew to the NCP, the mount slews up to the NCP but then the DEC motor carries on right past it and continues to slew through a further 360

[TCWORLD]

Which versions are you using (AstroEQ firmware, EQMOD), and what is your mount config?

[almcl]

Hi Tom

Thank you so much for responding, great support!

I am using an AstroEQ 4.6 - my assembly of your board and chips with Farnell supplied resistors, capacitors semiconductors &c.

The Firmware is 8.2 (loading utility 3.93)

EQMOD was version 2.00q but updated recently to 2.00w (made no difference).

ASCOM platform is 662.4294.NewCertificate

Cartes du Ciel (with which I observe the goings on and select goto targets) is 4.2.1

The mount is an EQ5 with NEMA 17 steppers configured with a custom park position of weights down, OTA pointing horizontally west. Controlled by a Panasonic Toughbook running Windows 11 pro.

Since the first post I have got a little closer to understanding the problem.  I also use an AZEQ6 with Cartes du Ciel and EQMOD, connected to the same laptop via a Lynx Astro cable.  This also has a custom park position of weights down OTA pointing west (identical to the EQ5's).  The problem I have discovered is that depsite parking both mounts (EQ5 or AZEQ6) in the same custom position each time, when I connect the other mount and switch on they disagree wildly about what the parking position is/was.

A consequence of this is that connecting the AstroEQ controlled mount after a previous session with the AZEQ6 means that the AstroEQ mount believes it is pointing at AZ 120

[almcl]

Sorry, the last two paragraphs keep getting truncated. They should read:

A consequence of this is that connecting the AstroEQ controlled mount after a previous session with the AZEQ6 means that the AstroEQ mount believes it is pointing at AZ 120 deg and ALT -33 deg instead of 270 deg and 0 deg.  This doesn't completely explain the observed behaviour (more than 360 deg of rotation in DEC) but it may indicate the source of the problem: why do they disagree?  Is it an EQMOD problem or a decoding of position one?

Sorry if that is abit confusing and not well explained.  Let me know if you need any other information

[TCWORLD]

If you park the AstroEQ, disconnect and power down, then power up, reconnect and unpark, does it work correctly? i.e. the EQMOD reconnects with the mount knowing where it was before.

I'm not sure how EQMOD stores the parked position, but at a rough guess it stores the raw encoder values. If that is the case and you then use and park the other mount, then unless EQMOD stores different park positions for each mount (don't know if it does), the encoder values would make no sense to the other mount and result in it thinking it was somewhere completely different.

For reference the encoder values are not in degrees, but rather a number of micro steps of the motor - so mounts with different gear ratios etc. would have effectively completely different unit sizes.

[almcl]

Thank you, Tom.  That explains it (I think).

Park, shut down, then reconnect the same mount and power up, all is well, but if I connect the other mount then that is where the problem occurs. 

mounts + different gear ratios = different interpretation of stored position.  I'll experiment to see if there's a point (Home, perhaps?) where they both coincide.

Thanks for the explanation.