Polar Align with RA/DEC or Alt/Az slew controls?

[Linwood]

I'm feeling stupid, like this should be really easy.

I just bought the pro version in preparation for a new mount that is coming that lacks an innate polar align. I have now a Paramount MyT which does nicely with tPoint, but I wanted to find out how this works.

The Sharpcap polar align seems oriented toward non-Goto scopes. Or I'm just missing something.

How do you get a goto scope to a counterwieght down, DEC 0 position? I've tried for about 30 minutes picking slew positions either in A/A format (no, 0 + latitude did not work), or ra/dec. There's no azimuth/hour angle.

Am I just missing the obvious? How do you GET to the position that sharpcap insists on?

And then once there, how do you rotate the RA axis 90 degrees? Do you put in something 6 hours different? That might work. (The manual joystick buttons in TSX just seem to move, even at 512x, just a fraction of a degree or so, I would wear out my finger with it. This would be the obvious solution, it just didn't work.).

I guess I just expected to hit a button, it would automatically slew to a couple stars, solve, and tell me what to do? Did I miss a wizard somewhere?

Or is this really only suitable for standing out with a hand controller by the mount? (My new mount won't even have a hand controller. I have one somewhere for the MyT, but it's still in the box I think).

I feel like I'm just missing the obvious... please tell me I'm being stupid, but tell me where the button is I'm missing.

Linwood

[JohnAstroFun]

Aloha Linwood,

Congrats on that new mount. I think a couple mounts (including my Mach 2) refer to that counter weight down position (and DEC 0) as a 'home position.' In my case, that home position is also defined as Park 3 (which makes it convenient). So there might be a way to define a new park position for your mount.

Here's what I do for polar align with Sharpcap Pro

Level the tripod/mount
Mount is at Park 3 (home position)
I do a manual rough/general polar align with the polar scope
Start Sharpcap
Unpark the mount (tracking turned off)
Start the Polar Align routine in Sharpcap
When Sharpcap prompts you to slew the RA 90 degrees, use your hand controller of software to slew the mount (either East or West) 90 degrees
(I use 600x as the slew speed)
So, basically slew the mount until the counter weight shaft is horizontal to the ground
At this point, Sharpcap will display a small yellow box which has to be adjusted by using the mount's AZ knobs and ALT wheel. I usually adjust the AZ first and then the ALT last. You might have to zoom in or out to see the yellow box. Once you get it aligned you're done. But here's another trick....

With the CW shaft still horizontal to the ground, close the Sharpcap Polar Align Routine
Open the Sharpcap Poalr Routine again and start it again
Eventually SharCap will tell you to rotate the RA axis 90 degrees. If you have that home position defined (as a park position), just send your mount to that home position and you' can see what your polar align error is going from CW horizontal to CW vertical. Hopefully the polar align error won't change that much (usually I don't adjust the mount again) Hope this makes sense! John

[Linwood]

I guess that's part of my problem, is I am mixing two mounts. Right now I have a MyT and don't really need Sharpcap for polar align as tPoint works fine. But I'm learning with it because it is what I have.

I have an AP1100 coming where I will need something, as TSX will go with the MyT.

I did not even order a keypad with the AP1100, as 99% of my use is imaging.

With the MyT as best I can tell there's only one park position, and I have it set where I load the OTA (I set up and tear down nightly), and because of Paramount's way of building dovetail clamps I have to slide it in carefully.

Anyway, the result is I'm trying to figure out how to guide the mount to the required positions by specifying slew coordinates (A/A or R/D either). I just can't seem to get a combination that actually do the motions Sharpcap requires. That's why this seems like I am missing something -- if I were doing this by hand it is so very simple. But I'm not.

I still do not understand why setting dec=90 and RA=current zenith did not work. I'm going to experiment again today in daylight, though obviously cannot actually run sharpcap (unless one of the simulators has an adequate sky survey download).

I also need to look more in TSX -- it just seems like their GUI joystick should really be able to ACT like a joystick, and just hold the button down. It just plain did not work that way last night. But things are more clear in daylight -- I think my brain shuts down in the late hours.

Maybe this becomes easier with the AP software, it sounds like it has multiple park positions I could use.

So just to be clear -- there's no automated (i.e. it controls the scope) way to get the initial plate solves in Sharpcap, right?

But shouldn't there be a RA/DEC coordinate I can use (adjusting for each night's position of course)? I still do not get why that did not work, it just kept saying "rotate further".

[admin]

Hi,

As long as you are at DEC=90 (or close) then the starting RA position doesn't really matter - start anywhere and rotate through ~90 degrees in either direction and it should all be fine.

The reason the instructions read the way they do is that most people prefer instructions that give them exact steps to carry out - it also helps that the starting point is the default park position for most mounts. Some people who only just have a view of polaris due to obstructions nearly blocking it start at 45 degrees left of upright and move to 45 degrees right - that keeps the OTA just a bit higher than going upright to horizontal.

I should also point out that the 90 degree rotation doesn't need to be exact. Just let SharpCap connect to your ASCOM driver, set a high speed of movement and hold down either the E or W buttons until you reach a large enough rotation.

You can find more guidance on polar alignment problems here : https://www.sharpcap.co.uk/sharpcap/fea ... leshooting

cheers,

Robin

[Linwood]

OK, that's new... I need to look. I looked through the menus and never saw a place to slew manually with sharpcap. That will help a lot. Guess I need to read more of the manual.

Thanks.

[JohnAstroFun]

I'm pretty sure the AP 1100 has 4 pre-defined park positions (one of them being the special home/Park 3 position). You can probably add one more park position in APCC, but I don't think the other ones can be changed...

I just looked at the MyT user manual real quick and it looks like that mount might have only one pre-defined park position. And it sounds like the park position that you are using is needed for mounting the scope to the mount's dovetail bar. So probably not best to mess with that!

If the MyT mount doesn't have any DEC clutch knobs and RA clutch knobs that can be loosened (to manually rotate the dec and ra axis), then it I guess it could be a little tricky getting the mount pointed to what some call the zero home position (CW shaft vertical and DEC axis pointed North). But, as long as you're pointed fairly close to Polaris and have enough stars showing up, and can still see those stars after rotating the axis RA 90 degrees, Sharpcap will find the NCP for you.

This link has some screen shots for the polar align routine
https://www.sharpcap.co.uk/sharpcap/fea ... -alignment

[Linwood]

Yeah, I can unlock the axes. I'm just trying to do the initial plate solves from inside the house where a computer is. What I do now is go out with a phone where I can see a looping image and crosshairs, and move the azimuth and elevation to make them align. It sounds like I'm doing something similar here. Maybe I'm focused too much in doing the plate solve stuff inside. I could try a phone next time outside, and just unlock and move it.

Or maybe I just wait for the AP110 and figure it out with that software.

I guess it was just such culture shock to go from tPoint which is so automated for the polar align (i.e. touching the scope physically only at the last moment) that I was looking for the same. I'm not sure there is a good reason to.

Thanks for the pointers.

[JohnAstroFun]

Aloha Linwood,

I thought I saw something in the MyT user manual about defining a 'home position' while used in conjunction with the SkyX... Not really sure if that helps. Maybe that home position could be configured and used some how. I'm have zero experience with the MyT, but it seems like a nice mount (as well as the ap 1100)!

[Linwood]

Home in MyT is a specific location (kind of west and up) that it uses as an initial calibration so it knows where it is pointing. I don't think it can be changed. Park can be set, but I see only one park position.

I think I've really made my approach too MyT oriented, since I have no need in MyT. It's the AP1100 I don't have yet which will be an issue, with all different software yet to learn.

[JohnAstroFun]

I hear ya!

The APCC user manual is pretty good, but there's still a learning curve there. The AP forums are usually pretty good at responding to any questions you might have. I had my mount set up in the house for a couple weeks while going thru some of the setup stuff. I just connect the laptop to the mount with an Ethernet cable and that seems to work pretty good. I also got it to work with Stellarium.

Now I'm going to try some plate solving with Sharpcap. Your mount will probably be using JNOW coordinates and I think Sharpcap will convert any J2000 coordinates (that comes from all the plate solvers) to JNOW which should be a big help. Good luck with that 1100 !!