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Orion Atlas Pro AZ/EQ - GT GoTo Issues

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#1 tclehman1969

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Posted 18 March 2019 - 06:30 PM

Good afternoon, all! Ive been away fro astronomy for a bit so I need a little refresher I think for getting my GoTos more accurate. Just had my scope and Atlas out the other night and I just could not get accurate gotos. Everything was off several degrees.

I polar aligned normally and I think it was on. Ran my 2-Star align and could not get it in at all. Using my C8 with a 36mm eyepiece, my targets were not even in the field of view. I looked through finder and in the 8x50 targets were off to the edge of view. At any rate, would use the hand controller and get star centered. Then go to second star and center it. Then, for giggles and grins, I’d view a star or other easily visible object in the list, used hand controller to select it and sure enough, still off be a huge bunch, not even in field of view of my main scope and way off to side in finder. So, repeated 2 star align using same stars as before. When doing this, it’s as if no star alignment had been done as stars appeared in exactly same spot in finder as they did when first aligning.

Am I skipping a step here? Any thoughts? Help!!🤪

#2 wrnchhead

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Posted 18 March 2019 - 06:44 PM

Is the time and location etc correct? Daylight saving time just started also.

#3 Astrolite

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Posted 18 March 2019 - 07:00 PM

I have an AZ-EQ5 and actually have never even used it in equatorial mode, so I am no expert for sure. But when I read about your problem I did do a quick read of my manual and the one thing that seemed to get mentioned quite often was cone error and how that will affect the mounts goto function. You might try a three star alignment, according to the manual this compensates for cone error. I assume you have entered the correct setup data and are using either a high power eyepiece or crosshair eyepiece for your alignment.



#4 tclehman1969

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Posted 19 March 2019 - 12:59 PM

Hey, thanks, all! Yes, data input correctly and I did enter in for daylight savings. Also got copy of Syndcan manual. I’ve been going through Atlas manual which doesn’t go into this at all. I forgot about the Synscal manual! One thing I’m getting is Caution previous NPE or something like that popping up. It seems as though doing a 3 Star will reset that? Naturally I didn’t bring manual with me to work and out so called WiFi is atrocious🤬 Something to check on.

#5 johnpd

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Posted 20 March 2019 - 04:15 AM

I have the AZ-EQ6 (also the AZ-EQ5) which I normally use in Alt-Az Mode. I assume you are starting from a proper Home position with relatively decent polar alignment. The first alignment star may be a little off, but the second should be better.

 

Look at the pages of the manual regarding the best alignment stars to use. The hand controller gives you a list of alignment stars starting with the brightest and going down in magnitude. If you chose the first two, these may not be the optimal pair to use. If you are doing the 2-star alignment, the difference in RA should be between 3 and 9 hours (optimal around 6 hours or roughly 90 degrees). The difference between the stars in Dec should be between 10 and 30 degrees. Although they do not say it under the 2-star alignment (they do mention it under the 3-star alignment), use two stars on the same side of the meridian. I have found this essential in Alt-Az Mode otherwise I can get very mixed pointing results if I cross the meridian for the second alignment star.

 

Also you should disable the Auxiliary Encoders as this can affect GoTos as well. I ignore that NPE message (just "ESC" out of it) as it gives me only a 1 second NPE value. I will have to set that to zero but it has not been an issue since I use Alt-Az.

 

Good Luck,

  JohnD



#6 Eric Seavey

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Posted 22 March 2019 - 04:21 PM

Have you updated the firmware?  Also the firmware for the motor drives need to be updated.  With mine I found it can be off a little. Using the Pointing Accuracy Enhancement, do can significantly improve the accuracy near your target.



#7 tclehman1969

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Posted 22 March 2019 - 07:09 PM

Have you updated the firmware?  Also the firmware for the motor drives need to be updated.  With mine I found it can be off a little. Using the Pointing Accuracy Enhancement, do can significantly improve the accuracy near your target.

 

Yes, running the latest, whatever that happens to be, but just updated a few weeks back. Good point on the motor firmware. I did do that a bit ago, but since then I was stupid and fried my controller in the mount -- don't ask, just know it was dumb! I received a replacement controller but haven't run the motor update. Might take a look at that. Thanks!



#8 tclehman1969

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Posted 22 March 2019 - 07:53 PM

OK, some updates on my issue, some might be equipment, but most likely me!

 

Had a chance last night to do a few things. First,

 

I checked to see if the main scope and the polar scope are aligned properly. Using Polaris, I centered Polaris in the polar scope. When looking through my C8, error there was pretty negligible, not dead on, but pretty darn close. 

 

Then moved on to next steps.

 

  • Powered on mount and did a polar alignment using the polar scope and app called PolarAlign. Moved mount accordingly and moved on.
  • Set out to do a 3 star alignment. Started to move scope to the first star, Procyon, and stopped it before it got there. I did that because I misidentified Procyon which was behind a tree. 
  • Selected to Park Scope. After parking, decided to do a "Reset to Factory" on the hand controller. Figured it couldn't hurt. 
  • Powered mount off, waited a bit, and then turned back on.
  • Entered Lat/Long, time zone (-08:00 for here in California), time on the clock, then selected Yes for Daylight Savings Time? question on the controller, so am assuming it adjusts the time accordingly. 
  • Started a 3 Star Alignment. Stars used were: Castor (might have been Pollux), Capella and Regulus. When selecting Castor or Pollux the star was in field of finder, so easy to find and adjust. Second star, Capella, was pretty close to being on, Regulus was also pretty good, but needed some adjustment like Capella. After completing this the Mel was -000* 08' 39" with the Maz at -000* 01' 02"
  • Once completing that, I then selected the Polar Alignment option on the hand controller. The scope through the option on the controller, selected Castor. It had me center it. Then it went off the star with the instructions to adjust using Altitude Boltadjustment only. Then it moved away from the star but only very slightly, if at all, stating using Azimuth Bolts Only center the star. There was essentially no adjustment needed. Upon completing this step the hand controller showed a Mel of -000* 00' 01" and a Maz of +000* 00' 01"
  • After this, I started going to objects, but still it seems to be off a bit. By off a bit, I mean that the object doesn't always get into the field of view of the C8 with 36mm eyepiece. With one exception, M44 (Beehive) when I moved to it was dead on perfect. It's these kind of inconsistencies that are troubling. Sometimes, there will be a camera hanging on the scope and I  won't be able to hunt around with it on, and many things as you are all aware, too dim for a 50mm finder. 

 

I'm thinking that I probably should have done a new 3 star alignment since I did make adjustments to the mount position per the Polar Alignment option. Also, since the Polar Alignment had me move the elevation bolt a bit, it would seem to me then that the polar scope reticle isn't aligned. Is that a fair guess? Strangely, however, I have checked its alignment by setting on a fixed point (top of a power pole) and rotated the RA access and it sits dead on the circle on the polar scope reticle. 

 

Any more thoughts? Of course, I know it will be a bit before I can get back out to use the scope -- rain and cloudy conditions for the next week here...of course, right?!


Edited by tclehman1969, 22 March 2019 - 07:59 PM.


#9 Eric Seavey

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Posted 22 March 2019 - 08:00 PM

Yes, the polar alignment on the HC is an iterative process, you need to do a 3 star alignment, then polar align, then 3 star alignment, check polar alignment again and finalize with 3 star alignment.  I will say the the polar alignment with this method does take a bit of time.  Now I just use Sharpcap polar align method with my autoguider system.



#10 tclehman1969

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Posted 14 April 2019 - 12:35 AM

OK, clear skies and free time have finally come together at the same time! Got my scope out and tried some stuff. First, just pointed polar scope at Polaris and centered it, nothing more. Then I conducted a 3 star alignment. Each star needed some adjustment to center.

 

Then I did a Polar Align using the hand controller. Did what I needed to do according to instructions on the controller. Redid a 3 star alignment. Again, stars were never centered. But did the alignment anyway. 

 

Then did a second Polar Align using the hand controller. Did that stuff. Then followed that up with this time a 2 star alignment. Again, stars only centered when I used the direction indicators. 

 

So, after three star aligns (2 X 3-star, and 1X2-star) I just tried to go to an object, selecting M 44, the Beehive. Nice and big and bright. Entered into the hand controller and - BAM! Dead on center. Awesome. Tried another object, I think M 13. Again, dead on in the middle. Tried another object, M 101. Again, dead in the middle. Everything I went to was at or very near the middle of the field of view. Shut down for the evening, but left scope outside, and got some shut eye for a couple hours.

 

Came back out, powered up, did a 3-star align, each star requiring adjustment to center, selected M 57, and again, right near the middle of my field of view. I stopped for the night after getting a few unguided images of the Ring as I had some high clouds coming in and seeing was not good this particular night.

 

Question for y'all: It was my belief that when doing a 2, or 3-star alignment that the stars should come pretty close to center, especially if repeating the alignment process. Is this not what happens?


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#11 Eric Seavey

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Posted 14 April 2019 - 07:56 AM

If you changed the ALT and/or AZ for the polar alignment, you will have some shift.  If you park your scope, you won't theoretically need to so another alignment.  Just turn on your scope, enter the time and unpark it, and it should be ok.



#12 cloudybruce

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Posted 14 April 2019 - 08:45 PM

Problems and solution with the Atlas Pro mount

 

I bought the Orion Atlas Pro mount June 2018.  I also own a Orion Skyview Pro mount.  The Skyview mount goto performance has been bulletproof.  I can't say likewise for the Atlas Pro

 

At times, I can get aligned within a few minutes of arc.  Other time: nada!  I have been unable to discern what made the difference.

 

I am very aware of the need for accurate time, lat, and long input and polar alignment using the finder scope circular reticule as a clock face, as well as having the scope and mount very well balanced.

 

A few times, of late, when aligning, and having the C11 telescope slew to a new alignment star, the mount made a hideous squawk, and quit turning.  The stepper drive motors were stalling (required torque exceed pullout torque).  I researched this subject and was surprised to learn that the pullout torque rapidly diminishes with stepper motor RPM.

 

Maximum motor torque relates to the square of the motor current, hence, the applied motor voltage.

 

If wiring resistance from the battery to the mount causes voltage drop under high motor current, the pullout torque may diminish to be lower than required for mount movement at the instant.

 

I measured the resistance of the wiring from the 12V 24AH jell cell battery to the connector tat mates with the mount.  It was about 1/2 ohm.

 

I have coiled the cords so they don't hang up when the mount slews.  An aside, coiling cords is easily done by winding straight around a 1/4" wood dowel, then heating them with a hot air gun until the wiring insulation gets shiny (almost melting).  After the cord cools, it retains the coiled condition.

 

Coiling cords can easily take a 6' straight cord and make it a 9" coiled cord.

 

Aha!!!  I replaced the motor wiring with 12-gauge outdoor wiring cable: 12' length

 

So much for this long-winded discussion.  I coiled about half 12' of the outdoor wiring cable, and spliced it to the mating connector cable on the mount.  The measured loop resistance of this new cable assembly was 93 milliohms (0.093 ohms)

 

Since then, I have had great alignment and no mount squawks when slewing.


Edited by cloudybruce, 14 April 2019 - 08:49 PM.



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