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Equipment Discussions >> Mounts

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Moromete
professor emeritus


Reged: 02/15/12

Loc: Romania
Re: EQ6/Atlas Polar align issues... new [Re: WillCarney]
      #6062989 - 09/04/13 04:28 PM

Is the polar align routine in firmware v3.35 a copy of Alignmaster software routine consdering you have to adjust the mount separately in AZ and ALT?

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telfish
sage
*****

Reged: 11/17/10

Loc: Adirondack Mountains NY
Re: EQ6/Atlas Polar align issues... new [Re: Moromete]
      #6062998 - 09/04/13 04:31 PM

Quote:

Is the polar align routine in firmware v3.35 a copy of Alignmaster software routine consdering you have to adjust the mount separately in AZ and ALT?




It's pretty similar, for me the Alignmaster routine gives better repeatable results.


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Moromete
professor emeritus


Reged: 02/15/12

Loc: Romania
Re: EQ6/Atlas Polar align issues... [Re: telfish]
      #6063010 - 09/04/13 04:38 PM

I suppose Celestron ASPA is more accurate and easier to use because:
- you actualy center the star near the meridian once, not in 2 steps like with Skywatcher
- it computes the polar alignment error based on 4 callibration stars and not just 1 like Skywatcher does.

Has anyone compared in the field the Celestron ASPA and Skywatcher firmware v3.35 polar align routine?


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Zad
super member


Reged: 01/05/08

Re: EQ6/Atlas Polar align issues... new [Re: Foehammer]
      #6077661 - 09/12/13 08:08 PM

Quote:

Hi all

Spent the whole night trying to do the Polar re-align routine on my EQ6 mount with no success. I've just upgraded from a CG5 and was very familiar with ASPA (which was a breeze to get right and get great results!) but something seems off with Synscan! I'm running version 3.28 (upgrading today to 3.35). What I've failed to understand is: How can you ONLY use the AZ bolts or ONLY use the ALT bolts to align a star in the eyepiece without having to use BOTH AT THE SAME TIME??? I must have done 10 or 12 3-star alignments thinking I was off but each time when going into the polar routine my selected star (and I tried various from the very short list of maybe 5 stars available to you) would be off in both ALT and AZ by 3 or 4 degrees.

So to sum up: After doing a successful 3-star alignment and heading into the polar re-align routine, selecting a star and centering it (using reticle ep) the star then is positioned by synscan to where it should be based on the user's input (time/date/lat/long/3 star alignmt) and asks to correct ONLY in Azimuth first (which is what I find odd and impossible to do!) and then veers off again and asks to correct ONLY in Altitude... is this right? In my case when needing to correct for AZ the star would be off in both AZ and ALT by a good margin which was impossible for me to correct using ONLY one of the two axis...

...I miss ASPA...




According to the manual, you don't adjust the alt/az BOLTS, you adjust using the direction keys on the hand controller to slew to the target. Think of it this way: you are not adjusting the mount itself, you are training the computer as to how far off your mount is aligned, and in what direction, so it can compensate. As long as you are close to polar alignment, it shouldn't be a problem. That's why you can just rough align with the polar alignment scope.

If I am doing visual work, a 1-star alignment has worked well for me. I usually do a 3-star alignment when doing AP, and have no trouble.


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rmollise
Postmaster
*****

Reged: 07/06/07

Re: EQ6/Atlas Polar align issues... new [Re: Zad]
      #6077691 - 09/12/13 08:42 PM

Quote:


According to the manual, you don't adjust the alt/az BOLTS, you adjust using the direction keys on the hand controller to slew to the target. Think of it this way: you are not adjusting the mount itself, you are training the computer as to how far off your mount is aligned, and in what direction, so it can compensate. As long as you are close to polar alignment, it shouldn't be a problem. That's why you can just rough align with the polar alignment scope.






That isn't at all what is going on. The mount is not compensating for anything. The point is to allow you to easily adjust it in altitude and azimuth to get closer to the pole; that is all.


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Zad
super member


Reged: 01/05/08

Re: EQ6/Atlas Polar align issues... new [Re: rmollise]
      #6078024 - 09/12/13 11:49 PM

Quote:

Quote:


According to the manual, you don't adjust the alt/az BOLTS, you adjust using the direction keys on the hand controller to slew to the target. Think of it this way: you are not adjusting the mount itself, you are training the computer as to how far off your mount is aligned, and in what direction, so it can compensate. As long as you are close to polar alignment, it shouldn't be a problem. That's why you can just rough align with the polar alignment scope.






That isn't at all what is going on. The mount is not compensating for anything. The point is to allow you to easily adjust it in altitude and azimuth to get closer to the pole; that is all.




Here is a cut/paste directly from the manual:

3-Star Alignment
1. At the prompt of “Choose 1st Star,” use the scroll keys
to browse through a list of star names and choose
one you’re familiar with. Press ENTER. The mount will
then automatically slew the telescope toward that star.
2. After the mount stops, the hand controller will beep
and display “Use dir. keys to center object.” The
mount’s tracking function is also automatically turned
on to prevent the target star from drifting in the FOV of
the telescope.
3. Now use the direction keys to move the telescope to
center the star in the FOV of the finder scope.
4. Then look in the eyepiece and move the telescope
(using the directional keys) so that the chosen star is
centered in the field of view of the telescope eyepiece.
5. Press ENTER to confirm the star is centered.

As you can see from step 4, you use the directional keys on the hand controller to center the star, and then press the enter button. You are not adjusting the mount's physical alignment at all. You are compensating for pointing error. Here is another cut/past directly from the manual:

The SynScan hand controller divides the sky into 85 small
zones, and you can calibrate the pointing error for each of
these zones. The next time the SynScan controller tries to
locate an object in the calibrated zone (or a zone nearby), it
will automatically apply the recorded
calibration data to compensate
for the pointing error. This function is useful for locating
faint deep sky objects, and it is also helpful to obtain consistent
pointing accuracy for a permanent observatory.

Correct me if I'm wrong but reading things like "it will automatically apply the recorded calibration data to compensate for the pointing error." sure makes it sound like the software is compensating for the pointing error of the mount. Not to mention if you follow the directions, how are you further aligning the physical orientation of the mount by slewing? You aren't, because slewing doesn't do that. You are just showing the software how far off the physical orientation is to true polar alignment, and the software compensates. At least that is how I understand it.


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tclehman1969
sage
*****

Reged: 05/18/10

Loc: SF Bay Area, California
Re: EQ6/Atlas Polar align issues... new [Re: Zad]
      #6078113 - 09/13/13 01:10 AM

I might be wrong here, but there is another section about aligning the scope more accurately. If you follow the manual down to section 11.3 POlar Alignment Without A Polar Scope, it states in steps 5 onward, the following:

6. The mount will slew to a new position. When it stops, the screen will display “Adjust Altitude:”. By using ONLY the altitude control of the mount (do not touch the azimuth control), bring the reference star back to the closest point to the center of the FOV of the telescope’s eyepiece. Remember the reference star’s current position in the eyepiece for later adjustment. Press the ENTER key to confirm the centering operation.

7. The screen will now display the polar alignment error. Users can then use the data to determine whether or not to adjust the azimuth of the mount in the next step. Press the ENTER key again to proceed to the next step.

8. The mount will slew to a new position. When it stops, the screen will display “Adjust Azi- muth:” By using ONLY the azimuth control of the mount (do not touch the altitude control), bring the reference star back to the closest point to the previous position (at the end of Step 6). Press the ENTER key to confirm the centering operation.

9. The screen will display the polar alignment error again, press the ENTER button to end the polar alignment process.

10.Go back to the “Alignment” menu on the SynScan hand control and execute another 2-Star or 3-Star alignment, and then check the polar alignment error data reported at the end of the 2-star alignment or 3-star alignment.

Repeat Step 2 to Step 9 until the error is small enough and acceptable.Generally, users can get up to 1 arc-minute polar align- ment accuracy after repeating this polar alignment process 2 or 3 times.


I think this is what is being referred to, possibly.


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telfish
sage
*****

Reged: 11/17/10

Loc: Adirondack Mountains NY
Re: EQ6/Atlas Polar align issues... new [Re: Zad]
      #6078627 - 09/13/13 12:07 PM

You are talking about goto alignment. The Op and Rod are talking about POLAR alignment.

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telfish
sage
*****

Reged: 11/17/10

Loc: Adirondack Mountains NY
Re: EQ6/Atlas Polar align issues... new [Re: Zad]
      #6078629 - 09/13/13 12:09 PM

You are talking about goto alignment. The Op is talking anout POLAR alignment.

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Zad
super member


Reged: 01/05/08

Re: EQ6/Atlas Polar align issues... new [Re: telfish]
      #6078668 - 09/13/13 12:38 PM

Ahhhh... I knew that when I was correcting Uncle Rod, I must have something confused. Thanks for clarifying. So what would be the point of doing a polar alignment vs. a goto alignment? Unguided imaging? Or does the mount in question lack a polar alignment scope?

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rmollise
Postmaster
*****

Reged: 07/06/07

Re: EQ6/Atlas Polar align issues... new [Re: Zad]
      #6078672 - 09/13/13 12:41 PM

Quote:


Correct me if I'm wrong but reading things like "it will automatically apply the recorded calibration data to compensate for the pointing error." sure makes it sound like the software is compensating for the pointing error of the mount. Not to mention if you follow the directions, how are you further aligning the physical orientation of the mount by slewing? You aren't, because slewing doesn't do that. You are just showing the software how far off the physical orientation is to true polar alignment, and the software compensates. At least that is how I understand it.




Sorry, you are wrong: You referencing the go-to align procedure, not the polar align procedure ("resync") which includes the following:

6. The mount will slew to a new position. When it stops, the screen will display “Adjust Altitude:”. By using ONLY the altitude control of the mount (do not touch the azimuth control), bring the reference star back to the closest point to the center of the FOV of the telescope’s eyepiece. Remember the reference star’s current position in the eyepiece for later adjustment. Press the ENTER key to confirm the centering operation.

7. The screen will now display the polar alignment error. Users can then use the data to determine whether or not to adjust the azimuth of the mount in the next step. Press the ENTER key again to proceed to the next step.

8.The mount will slew to a new position. When it stops, the screen will display “Adjust Azimuth:” By using ONLY the azimuth control of the mount (do not touch the altitude control), bring the reference star back to the closest point to the previous position (at the end of Step 6). Press the ENTER key to confirm the centering operation.

9. The screen will display the polar alignment error again, press the ENTER button to end the polar alignment process.

And also, this procedure makes absolutely no adjustments to the go-to alignment model.



Edited by rmollise (09/13/13 12:43 PM)


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rmollise
Postmaster
*****

Reged: 07/06/07

Re: EQ6/Atlas Polar align issues... new [Re: Zad]
      #6078694 - 09/13/13 12:48 PM

Quote:

Ahhhh... I knew that when I was correcting Uncle Rod, I must have something confused. Thanks for clarifying. So what would be the point of doing a polar alignment vs. a goto alignment? Unguided imaging? Or does the mount in question lack a polar alignment scope?




You need to do both, to some extent anyway. You need at least a reasonably good polar alignment with this mount for good go-to accuracy in my experience. If you are imaging, you need as good a polar alignment as possible. If not, declination drift/field rotation will kill your images. AND you need to do as good a go-to alignment as possible to increase the accuracy of the SynScan polar alignment procedure.

Me? In most cases, for 5 minute or less exposures or for visual or video observing, I find the good old polar alignment scope good enough. It is nice to have the AllStar polar alignment procedure available, however.


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Zad
super member


Reged: 01/05/08

Re: EQ6/Atlas Polar align issues... new [Re: rmollise]
      #6078749 - 09/13/13 01:16 PM

Quote:


You need to do both, to some extent anyway. You need at least a reasonably good polar alignment with this mount for good go-to accuracy in my experience. If you are imaging, you need as good a polar alignment as possible. If not, declination drift/field rotation will kill your images. AND you need to do as good a go-to alignment as possible to increase the accuracy of the SynScan polar alignment procedure.

Me? In most cases, for 5 minute or less exposures or for visual or video observing, I find the good old polar alignment scope good enough. It is nice to have the AllStar polar alignment procedure available, however.




That makes perfect sense. With my setup and location, I rarely image more than 3 minute subs. I have had great success with just a polar alignment using the polar alignment scope, a 3-star alignment, and PHD Guiding. I guess I just haven't had the need for a more accurate polar alignment. I may try it out at home, just to see if my polar alignment scope needs any tweeking. On the other hand, if it ain't broke...


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neptun2
scholastic sledgehammer


Reged: 03/04/07

Loc: Bulgaria
Re: EQ6/Atlas Polar align issues... new [Re: Zad]
      #6079793 - 09/14/13 04:15 AM

I use the new polar align procedure since the first beta firmwares that support it (3.28). Here are some recommendations to get the best possible results:

1. Using the "polar finder" program or other way see where polaris should be in the polar scope.

2. Looking through the polar roughly place polaris where it should be according to the program using the ALT and AZ adjustment bolts.

3. Make good 3-star goto alignment centering the stars precisely. I use the live view of my DSLR with a grid to achieve that.

4. Start the polar align routine. When asked to select star from the list use one which was not used previously during the 3-star alignment.

5. when ready with the polar alignment routine park the mount, shut it down, power it back up, select not to start from parked and redo another 3-star alignment.

Using this technique with 3.35 i get good goto accuracy and polar alignment error in AZ and ALT not exceeding 30" (at least this reports the hand controller). This is only with one iteration of the polar align routine and i get 15 minute subs at 900mm focal length without any field rotation.


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