SabS "Please confirm the telescope points within 30 degrees nearly the SCP".

Just poor English.

It means that the ASIAIR thinks that you are located in the southern hemisphere, and the plate that it took showed that the OTA is pointed more than 30 degrees away from the South Celestial Pole.

Chen

SabS I am located in the southern hemisphere. South Australia.

Yeah, it says that the initial plate solve succeeded, but the solved plate shows that the OTA is pointed too far from the SCP.

You need to be within 30 degrees of the pole, otherwise the algorithm used in the ASIAIR will produce an unacceptable amount of error even when it says you are perfectly polar aligned. If memory serves, a 30 degree offset to adjust the polar aligment produced a few arc minutes of error.

Try using a compass and a inclinometer to roughly set up the mount for your mount's RA axis before starting the automatic polar alignment process. You do not need to use ASIAIR's polar alignment, either. Any other method will work too (PoleMaster, reticle in Polar Scope, polar alignment in SharpCap, etc). Polar alignment simply sets the RA axis of your mount to be parallel with the Earth's rotation axis.

By the way, the number of stars you are getting with a 1 second exposure sounds a little fishy; but it might be correct -- can't tell unless we see one of your plates. I am not familiar with southern stars (when I started astronomy in the 1960s at a location (KL) a few degrees north of the Equator, I could see the Southern Cross -- really miss that constellation :-). ASIAIR may be taking noise and hot pixels to be stars. Try something like 2 to 3 seconds of exposure, if it still fails.

Chen

SabS Roughly I would have been a good 50 to 60 degrees off the SCP.

Oh yeah, that's way too far off (and who knows where the extra 60 decree RA slew will point the mount to).

ASIAIR basically does a triangulation by assuming that when it slews the RA by 60º, the mount's declination axis does not change even an iota.

I usually start with the declination at +89.5º (in northern hemisphere). I try to stay away from precisely 90º myself (there is a secant singularity at the pole), but otherwise try to stay within 1º to 2º of +90º declination to get best precision. Even when you are that close, there is a residual error of some 15 arc second (worse if the SCP is close to the horizon due to atmospheric refraction), so there is no need to polar align to better than 10 arc seconds, since the algorithm itself has a greater error than that.

Good luck.
Chen

SabS Now I just need to cut a tree off as its blocking my SCP

Ah, this is the case where you do need to set the declination of the OTA farther away from -90º.

Remember that the polar axis ("RA axis") is still needs to be finally pointed at the SCP (even if you cannot see it). However, by pointing your declination to a position away from the SCP, you can see from a planetarium program (like SkySafari) that you will be describing a constant-declination arc around the pole as you make that 60º RA slew. Use enough declination offset to make an arc above the tree.

(If the OTA is pointed directly at declination -90º, the plate solves at the start and the end will both be centered at the SCP, but one will be rotated relative to the other. I.e., both plates will be centered right on your tree. And that will not let you polar align.)

If it is still not clear how you can avoid the tree, I can draw a couple of diagrams for you.

You also do not need to start at the tip of the tree. You only need to do a plate solve at the first location and multiple plate solves at the post-60º position. In between those two positions, you can be fully obscured and ASIAIR will not care. (Indeed, I start my own Polar Alignment with the declination tilted 60 degrees over, so that after the 60º slew, I have the maximum clearance to get to the bolts of my compact mount.)

You get less accuracy as you plate solve farther from the pole Until it won't solve at all beyond 30º away from the pole. But if you have a low noise CMOS camera, you can probably do as well at 180 second exposures as you can do with 600 second exposures, depending on your Bortle or SQM number. With a 120 to 180 second exposure, your RA axis can be 2 arc minutes from the pole and still be acceptable. Your stacking program should be able to handle the long term field rotation.

30º is a long way from the pole. If you were in Tasmania, the pole is already some 42º above the horizon. So the OTA can actually be pointed 70º from the horizon (that is just 20º from overhead) and you can still get away with it. It is not as favorable at other parts of the continent, though. But I doubt your trees are tall enough to be 30 degrees taller than the SCP. Just make sure the RA axis is close to True South when you start. You will eventually have to nudge it to True south during polar alignment anyway, so might as well also start with it close by. That probably was the cause of the "too far" error that you got.

At least Santa and his sleigh won't be blocking your pole. It is weird though that Santa lives in the north where there is no land mass, while there is a large continent just to the south of you.

Chen

SabS

OK, here are some pictures.

The first represents what ZWO recommends. The green bar at the bottom is your horizon, the green blob is your tree to the south. The circles are constant declination lines, and the radial lines are constant RA lines.

The dotted rectangle is the plate that the ASIAIR takes before it rotates the RA axis of your mount by 60 degrees, and the solid rectangle is the position of the plates that the ASIAIR take after the 60 degree rotation.

With the ZWO recommendation, you start with the OTA that is pointed at the pole, after the 60º rotation, it simply tilts the camera angle, and you will never be able to Polar Align with an ASIAIR because the plates are obscured by the tree.

So, what you do is to point your OTA at a declination (in your case) that is not -90º. The RA axis itself is still mostly pointed at the pole (when you are done with polar alignment, the RA axis will be pointed precisely at the pole -- the whole point of polar alignment).

Notice that you do not have to start with the RA set so that your first plate is above your tree. If you have a slim tree (or chimney), you may be able to do better by starting at a different hour angle:

Chen