- This topic has 5 replies, 6 voices, and was last updated 8:13 am on 2021-05-30 by sheakev.
January 13, 2016 at 7:06 am #113034
Richard S. Wright Jr.Senior Moderator
I'm spending the week in it's entirety down at my observatory in South Florida. My neighbors and I are having a “closed star party” kind of event where some invitees from the industry and fellow imagers are camped out around the grounds of our little astronomy enclave. This means I can get some work done, but also that I'm interacting with a lot of other imagers, many of which have Paramounts and/or use TheSkyX for imaging. I have three Paramounts here, and in total we have 9 Paramounts here. There's also a good scattering of white AP mounts, Celestron, and others. None of us give the others a hard time about their hardware choices… it's a great group of well adjusted adults
. Some in observatories, many on piers setup portably. I'm learning a lot this week and listening to feature request “suggestions”. I can also see first hand how people are using the software and mounts and if they are struggling with anything. We made several “tweaks” to the daily build the came out after the Chiefland star party for the same reasons.
My friend Buddy has a plot here and has a Paramount MX+. He has a little dome just like mine, but also takes his Paramount “on the road”. I've worked with Buddy and walked him through all the setup steps and we've gone over it a few times. Never-the-less, Buddy asked me to put together a checklist for him. I thought this would make a great blog, and I may even do a video showing all these steps.
As they say, there is more than one way to skin a cat.. or make brownies. This is my “Recipe” if you will for chocolate brownies… your brownies may be made a little different (this is an analogy okay?). This is pretty much my routine and it works well for Buddy too, and who knows just having a check list may help solidify everything you need to do to get going too. There are a lot of judgment calls in this list… so don't take it as canon.
1. Make sure you have Daily Build 9332 or later.
2. Make sure your location is accurate if you’ve moved your scope from home to your dark sky site, camping location, etc.
3. Fire everything up. Connect to camera, mount, etc. Take a test exposure, just to make sure camera is communicating, etc.
4. Home the mount if you didn’t when you first connected to it.
5a. From the Tools menu, select “Rough Polar Alignment”. Follow the on-screen instructions. The better a job you do at leveling your mount, the less extreme your initial mount adjustments will need to be when you’ve done your first TPoint run.
5b. So, here’s the thing; just sight down the Versa-Plate to line up the star with where the mount is pointing. This is close enough. Use the sun or the moon if you want. One thing to be careful with is that the versa plate is shiny, and you might end up lining up the Versa-Plate with a reflection of the star or sun. As a thought experiment, this sounds impossible, but in practice it’s not that hard to get confused in the dark. Especially if it’s the sun because… well, you’re not supposed to be looking at the sun anyway and it gets uncomfortable quickly even if you’re trying to “glance” towards it.
6. From the main menu under Telescope, select TPoint Add-On. Click the Setup Tab, then the “TPoint Add On Settings” drop down. Select New, and when it asks to confirm tell it yes, you want to clear all the old data. This is just to make sure sure sure, you’re not adding to a previously unfinished model.
6. Okay, take a photo. Technically anywhere, but don’t take one near the meridian or the pole just because of some technical mumbo-jumbo. Image Link the photo, and click on it. Now, on the telescope Tab, click the “Add Pointing Sample” button. You should get the “Star Calibration Run” dialog. There are some radio buttons up top, make sure “Full” is selected.
7. Slew somewhere else now, on the other side of the meridian. Take another photo, image link the photo, click on it, “Add Pointing Sample”. Now you have two samples manually added, one on each side of the meridian. Adding two points manually ensures your image link settings are correct, and having one on either side of the meridian give’s TPoint a head start on the automated calibration when it does the first meridian flip.
8. Bring up the TPoint Add-On dialog again, and click the “Calibration Run” tab. Near the top is the “Automated Calibration” button. Work your way through the tabs, left to right. On the “Setup” tab, set your exposure time to 5 to 10 seconds, make sure the image scale matches for your binning mode (this should be the same as when you did the two manual image links). Set search area to the maximum of 8 if not already there. Next click “Create Pointing Targets”, and use the GUI to setup your samples all over the sky. I like to have “Randomize” off (Note that Patrick Wallace recommends that the positions of calibration points should be non-uniform, so you may choose to leave this on). Go down to about 30 degrees in altitude, and do 50-60 points if your setting up the dome, 25 if your more portable and just in a hurry.
9. Click “Acquire Pointing Samples” tab, and then the Run button. Watch it and make sure the images are linking okay. If not, you may need to either add some more samples manually, or turn on the all sky image link. If so, you were really quite far off on your rough polar alignment and you may need to start over if the mount adjustments (coming later) are too large. To turn on all sky for automated runs, go to Tools on the main menu, and select “Image Link”, then click the All Sky tab, and look for the check-box “Use All Sky Image Link for automated pointing runs”.
10. When the automated run is completed (do not worry about a few failed samples). Bring the TPoint add on dialog back up. Click Finish on the Calibration run tab, then click the Model tab, and then the “Super Model” button. Let it crunch for a few seconds, and then click Accept to take the model.
11. Now click the Polar Alignment Tab, and see what your altitude and azimuth adjustments need to be.
I do the Accurate polar alignment procedure a little out of band here…
12. Pick a brighter star low in the north or south, say 30 degrees or so above the horizon and perform a closed loop slew to it. I like to do this in advance of using the accurate polar alignment, it saves time. Turn on the cross hairs of the fits viewer, and then select the focus tab of the main camera dialog. Setup a repeating exposure of a second or two. The star should be in the middle of the cross hairs, and ideally no other nearby bright stars are in the view to confuse things.
13. Make the recommended adjustments from the polar alignment report to the mounts azimuth and altitude.
14. Start the “Accurate Polar Alignment” Wizard, by clicking the button on the polar alignment report screen. Click through when it tells you to slew to a star and/or closed loop slew, you’ve already done that. Don’t click too fast through, watch and see where it tells you it’s moved the mount and you need to adjust the azimuth and altitude to center the star. Since we’ve already made the coarse adjustments, we should be close and the bright star should be in the field of view at least, if not near the center.
15. Watching (or having a friend help) the star on the cross hairs, adjust the mount and center the star up in the cross hairs (you should still have this video-like focus loop going). Click commit.
16. You’re done. You should have a good polar alignment and good pointing. Calibrate your guider if you need to, focus if you need too, and start imaging.
17. If pointing is not quite what you’d like, you have two options. First, just use closed loop slew to center your objects. Or…
18. Perform a recalibration. You might should do this on subsequent evenings anyway if the mount may settle at a campsite on the grass/ground. Simply, go back to the “Automated Calibration” (on the TPoint Add-On Dialog/Calibration Tab). On the “Create Pointing Targets” tab, you don’t need so many points, say 12 or so. Click the “Acquire Pointing Targets” tab, and then the run button. It should pop up a dialog, and make SURE you select the radio button at top that says “Recalibrate Portable Telescope”. Let her rip…19. Image all nightJanuary 15, 2016 at 8:05 am #224756
Your polar alignment routine is very interesting. Thanks for throwing that idea out. Now that Accurate Polar Alignment has the suggested star feature, would you also be able to finish the TPoint run and make the polar alignment adjustments based on the PA report. Then start APA, closed loop slew to one of those stars and finally have APA make the offset slew which I assume would be tiny?January 24, 2016 at 8:05 pm #225078
I just tried that variation on the accurate polar alignment. I like it. Thanks for sharing!January 29, 2016 at 10:20 am #225297
Great article Richard. I've been working for a couple of weeks trying to master APA for remote use (I hate trying to figure stuff out in the field). What is the advantage of performing the calibration run before you start the APA tool?
NickApril 10, 2016 at 4:00 am #228297
Very nice write up Richard. For those that conduct portable setups, which is not me, maybe some screen shots would help if that is easier than making a video. Either way, your list will be a good tool for the portable imagers.
GlenMay 30, 2021 at 8:13 am #323722
Just found it, and as a person new to astronomy and new to an MX+ it was helpful but would love if it were to be updated.
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