ASIAir not driving EQ6-R pro mount correctly

brianboyle

I have an new EQ6-R Pro mount that is connected to my ZWO ASIAir Pro via a USB "printer cable".

After "syncing to mount" in the ASIAir app when the mount is in the home position; weights down - mount pointed due south (I live in New Zealand), the PA routine fails to drive the telescope 60deg after taking the initial exposure. Sometimes it doesn't move it all - sometimes it moves it way past 60deg.

After moving the mount by hand during PA, I move the mount to a patch of sky near my target, take an exposure, plate-solve and sync to mount. All works fine. But when I then use the ASIAir to GOTO the target, the mount drives to the correct Right Ascension but most of the time it goes to the wrong declination - twice as far from the target as the difference in dec between the target and the sync'ed position. It is effectively driving the dec axis in the opposite direction to the one it should (as if it was on the other side of the meridian). Second and third attempts at acquisition compound the error - ie the drives the mount is exactly the wrong way in dec.

This doesn't always happen (about 25% of the time it goes to the right position). Indeed the very first time I used it, the PA worked and it went straight to my first target after plate solving and syncing on a position nearby.

I suspect a newbie mistake on my part. But have other users encountered this and, hopefully, rectified it?

What am I doing wrong? Possibly it is due to setting the home position, ASIAir always appears to think the Home position is currently where I am pointing or, rather where it thinks I am pointing.

Otherwise I am really happy with my ASIAIr Pro - I think it is a great piece of equipment.

LCoronelP

brianboyle Hi mate, three years from this post, but currently i have exactly this problem, also with asiair (Plus) and eq6r pro

The declination moves to the opposite direction, also i noticed that the representation of the camera framing on the asiair app is 180deg rotated

I tried with Sony cameras, Canon cameras and also ZWO cameras and the behaviour it's the same: the Right Asc is correct but the Dec is almost anytime inverted when i use the goto.

Thanks for any help, that is very annoying problem.

w7ay

I don't think you are doing anything wrong; I have read plenty of reports of the same behavior (not moving at all, or moving well past the 60º) while the ASIAIR performs polar alignment.

The maths right close the spherical coordinate's pole is very prone to numerical error. So much so that I always start my polar alignment with the OTA pointed a little away from the pole. Polar alignment has never failed me, and I wonder if my precaution saved me -- if so, perhaps it will work for you too.

May I suggest that the next time that you start polar alignment, do not point the OTA directly at the pole (declination +/- 90º). The polar alignment exercise is to get the polar axis itself pointed at the pole; the OTA does *not* need to point at the pole.

Indeed, according to ZWO's documentation, the OTA can be up to 30 degrees from the pole to perform polar alignment, although I have discovered that the alignment accuracy is off the further the declination is away from +/- 90 degrees by using my mount simulator.

I start at a declination of +89.5º before entering the Polar Alignment window. In your case, I suggest using the ASIAIR GOTO (or hand controller) to move the declination to between -87º and -89.5º before starting polar alignment. See if the problem goes away. But be sure to be near to the mount when starting polar alignment, in case the mount still runs amok.

As a matter of fact, I don't even start polar alignment at the "counterweight pointed at ground" position, i.e., with OTA at top dead center above the RA axis. Instead, I start with the OTA tilted about 60º (4 hours) east of top dead center. After the automatic 60º westward rotation, the OTA ends up at top dead center above the RA axis. The reason I do this is because my OTA train blocks me from tightening my RainbowAstro mount's altitude locking bolts when it is tilted by 60 degrees from top dead center. As a result, I want the ending position to be close to top dead center.

If you don't have such blockages, you won't need to do this. I only mention it here to point out that not only does the declination need not be +/- 90º, the ASIAIR also does not care what the starting and ending RA angles are, as long as they are about 60 degrees apart.

Good luck,

Chen

brianboyle

Hi Chen,

Thanks for the tip. I will try pointing a little away from the pole for my next PA. But I still don’t understand why the ASIair is driving the Dec axis in the wrong direction during a standard GOTO.

w7ay

LCoronelP The declination moves to the opposite direction, also i noticed that the representation of the camera framing on the asiair app is 180deg rotated

Are you located in the southern hemisphere?

This is weird, since the ASIAIR does not really know how to move a mount. It simply sends a GOTO command with a given RA and Declination coordinate to the mount, and the mount is the one who knows which direction the motor should turn when it is given the RA and declination.

The mount's movement will depend on the hemisphere, longitude, time, etc. The ASIAIR may not have sent the correct hemisphere command to your mount, or equally likely, since we are talking about software from ZWO, had sent it the wrong hemisphere.

Next time you set everything up (before sending the GOTO), check the longitude on your hand controller. Then check the UTC time, and if it is set correctly to the North or South hemisphere (i.e., that your latitude shows the correct sign).

If you are in the northern hemisphere, the polar axis should point to the North Celestial Pole, and likewise, SCP if you are in the southern hemisphere.

Chen

LCoronelP

w7ay Hi again and thanks for the fast help!

I'm at northern hemisphere, at North of Portugal, if i use only the mount (without the asiair), do the one/two stars alignment and use the mount goto, works perfecly.

I will try to recheck again the data on the mount again tonight.

I don't know if the asiair have some configuration to reverse the dec or something like that.

Thanks again! 🙂

LCoronelP

Hello again. After all I have a response for this problem: Sony hate ZWO (or viceversa)

Sometimes the Sony don't send the taken image to the Asiair and keep it in a some type of buffer, after that, if you take some image and try to solve, the asiair in reality solve the previous image! So, when you sync and do the goto, the telescope go in any direction (from the previous solved image)

Solution: discconect the camera to the Asiair, power down both, power up and connect again.

After that the buffer is gone and the system works perfecly (unless you do a autofocus process or PA, because take a lot of images and sometimes the Sony don't send the image to the Asiair and... All is bad again.

I hope that help somebody having this problem with Sony and Asiair!!!

Also i hope someday the Asiair can do something with this phantom images and clear the buffer of the Sony or some similar.

Thanks for all the help 🙂