I have been getting my new g11t mount out as often as possible and have had some success using it, but it isn’t consistent. The thing I am not sure about is the sequence of polar alignment and pointing accuracy procedures.?If I want to get a good polar alignment, for auto guiding, and have good pointing accuracy, what do I do first? If I am getting these sequences correct, then the pointing accuracy is a four star sequence, starting west for three stars then going east for the last star. Polar alignment is staying west for all four stars, with the last star giving me a PAC option to center the last star with alt/elevation knobs being used instead of the hand controller.?
Should I doing both procedures, one after the other? If I am doing both procedures, then which do I do first? Can I do the pointing accuracy thing first then go to a bright star and center it?

I have watched the videos a number of times and I have not put it all together yet.

Hi Jeff,

Are you using the Gemini-2 Hand Controller by itself???
You mentioned autoguiding, so can we presume you have a camera(s) and software ?
The best choice options kinda depend on your available camera and software resources...

Like many of the others, I have found that Sharpcap's polar alignment routine is really easy and fast, requiring no hand controller interaction except for a single RA slew (or from the Gemini.Net interface).
If you haven't tried it, you might want to...

It gives you near real-time errors to adjust out in arc seconds for mount adjustments and getter yet, gives you what direction to make the adjustments, can't get much easier than that...
At first, I was using the Polemaster camera with Sharpcap, but found I got better results with my main imaging camera (1.4 arc seconds per pixel).
I'm sure others will either confirm or offer alternatives...

When I start, I do the Sharpcap polar alignment first, then start modeling until I get the PAC option, then switch and build the model for the other side until I get the PAC option.
By then my pointing is more than accurate enough...
I know that I don't have to model at all if plate solving, but I enjoy doing it and it only takes about 5 minutes, and I then have the peace of mind to know everything is right...

I struggled with cone error for awhile, as it really seems to affect polar alignment from my imaging camera's perspective (some slews it was excellent, others not so good),
and my results became much more consistent when I minimized it (with shimming).

Astronut Tim

PS: I usually also check the orientation of my cameras using Sharpcap's reticle and alternating between E and W movements using the Center speed.
I rotate the cameras (if needed) until the star stays on the reticle line when nudging E and W.
I check this on both my main and guiding camera, as well as my EAA camera on my finder.
I know that I don't have to do this for PHD2, etc. But I believe that it makes everything easier when East = East and not East = North East (or worse).

I know that all the major software out there claims they don't care about this orientation and will compensate for it, but all I know is that?I have gotten consistently better results overall after this step...

Astronut Tim

HI Jeff

If I recall correctly you have a C14 and a DSLR, and I think you are moving out the scope each nigth?

You definitely have your work cut out for you - it's a demanding pixel scale.?

If you are doing polar alignment via the polar scope(?) you will want to do that first. I sent you a video on how to do polar alignment via the scope. If you are doing it another way, you'll want to nail down polar alignment first. Visual polar align will get you a rough polar align, so your exposure lengths may be more limited.?

next you'll do your alignments. Ideally three on the east and three on the west. It's best to choose stars that are significantly different in both RA and DEC.?

you can do GOTO, choose a bright star, slew to it, then using your hand controller on Move or Center speeds, center the star in your guidescope, then your DSLR's frame.?
then choose Menu->Align->alignment

repeat for 3 stars on east and 3 stars on west

that should get you reasonable sky model

If and when you move to a true astro camera, you'll be able to ditch all this and use software-assisted polar alignment and plate solving and all this will be moot

hth

Brian

Like Tim I'm now using Sharpcap to Polar Align. Here is a video that helped me get it down pat:?
Unlike Tim, once I have Polar Aligned with Sharpcap, the Polar Alignment is done, and it needs no other corrections.

Consistencies are a matter of routine. I have 3 boards I set my HD tripod on that I made to adjust the tripod as level as possible. Lot's of folks have told me it doesn't matter, I've proven to myself it does. So I begin with as level a base as possible.
Once my tripod is level and plumb, I tend to leave it so it is roughly polar aligned. I just cover it after the rest is hauled back inside, so I have my base for the next night.
Each night, I like to check the level of my HD Tripod. I use my Smart Tool digital level, which has proven accurate over the years I've had it and used it. So I always know my base platform is level and pointing as straight into outer space as I can humanly set it. Then I assemble my "Chunks" of my mount. The RA on the EX 12, The Dec on the RAEXT, Then my Telescope from the clamp up. Everything stays in balance, because there is only the consistent "Chunks" being assembled.

I DO NOT turn on the Gemini until I have my Sharpcap PA routine completed. Polar Alignment is a function of mechanical alignment to get your assembled equipment aimed at the North Celestial Pole. As such, we don't want the Gemini powered up and the mounts natural tracking function messing up our Polar Aligning steps.
So the Gemini stays Off until the PA is completed. At that point, when your PA is as good as you can humanly get it, you power up the Gemini and it's home position is at your Polar Alignment.
(I personally take it as a challenge to get my PA to be all zero's. The Altitude I can get with my GM811G fairly easily, the Azimuth is a little trickier. Az wants to dilly-dally from 0 to 3. I believe the atmosphere has some influence)

Once I'm satisfied I cannot do better with my Polar Alignment, I turn on my Gemini and begin my Modeling. And those results are really satisfying as I find the Aligning Stars come in when the telescope completes a slew.
I've been using a laser lately to aim my telescope during Modeling. It shows as a green line reaching towards the Star in the view. So it confirms what star needs to be centered. Presently I'm using a Z-Bolt astronomy laser mounted at about an 08:00 alignment to my Main Telescope.
Incidentally, I do all my PA and Alignment (Modeling) through my MOT. Because my Main Optical Tube is what matters. So it is what I need to be accurate.

That is my routine and method. Adopt any of it that fits for your needs.

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SonnyE


(I suggest viewed in full screen)

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For polar alignment I use "drift align" within PHD2. It works really well, and you don't need to see the north star to do it. I've pounded in three threaded pipes with a flange on the end, into the ground to make a sort of permanent tripod locator. I'm able to take in my mount every night, but re-locate it back to a pretty precise location, and keep my polar alignment, sometimes for months. This means that I save a lot of time only needing to do polar alignments once in a while. Look at the tripod feet to see what I mean about the flanged pipe:??Here's an image I found of threaded pipe with a flange attached.?

I set my Gemini to do a cold boot everytime. There may be a better way, but that's what I do. I then use Kstars/Ekos to do a couple plate solves. Next I make sure the focus is good using a?bahtinov mask pointing at a bright star. Finally I point to my target and start capturing images.?

Jamie

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