Date   

Re: Polar Align, Zenith method

Roland Christen
 


So it appears that when using the 'zeni th' polar alignment method, the RA drift is corrected by adjusting the altitude and the DEC drift is corrected by adjusting the azimuth (?).
YES, that is correct.

Rolando


-----Original Message-----
From: craig.young.m8@... [ap-gto]
To: ap-gto
Sent: Fri, Aug 25, 2017 2:58 pm
Subject: [ap-gto] Polar Align, Zenith method



In another post, Howard recommended I try the 'zenith' method for final alignment.  Not being familiar with this I decided last night to give it a try.

Two nights ago I used TPoint to measure the error in Polar alignment and found azimith was perfect and altitude needed a small correction.  After a couple of passes I had the altitude within an arc-minute, good enough to try it.  I next used APPM to create a 30 point model in the eastern sky and then did several 10 minute unguided tests in various parts of the eastern sky.  All of the images showed nice round stars.

I then tried the zenith method.  I turned off APPM tracking and moved the telescope to -38 declination (my latitude) and -10 minutes HA.  A plate solve showed this was within a few minutes of the zenith.  My method was to move the scope to -10 minutes HA, take a 10 second image, wait 5 minutes then take another 10 second image.  Sure enough the star drif ted in the RA direction.  After a few iterations I determined the altitude had to be raised.  At the end I had no drift in RA but a slight drift in DEC which I left for now.

I then did another 30 point APPM model and tested it by moving the scope to 0 DEC and -1 hour HA.  A 5 minute exposure showed no drift in RA but a small drift in DEC so the stars were elongated.  The amount of elongation (drift in DEC) matched what I saw at the zenith when I finished the altitude adjustment.

To make sure nothing else had changed, I turned off the APPM model and went back to TPoint.  It showed the altitude was too high by 2.3 arc minutes, so I lowered it back down and ended up with <0.9 arc minutes which is about what I had two nights ago.  I then reloaded the APPM model from two nights ago and again tested using a 5 minute image at 0 DEC and -1 hour RA.  Stars were nice and round again.

So it appears that when using the 'zeni th' polar alignment method, the RA drift is corrected by adjusting the altitude and the DEC drift is corrected by adjusting the azimuth (?).  Unfortunately the clouds came in and I was not able to test this last night.  If indeed this is true then the 'zenith' method is a great way for polar aligning a mount.  There is no refraction involved since the scope is pointed precisely at the zenith.  And all sites should be able to see the zenith compared to those having trouble seeing the eastern sky (drift method) or a pole star (none down here in the southern hemisphere), or visibility of the celestial pole (polemaster).

So before I venture out on the next clear night and try this again, has anyone else tried this method?  Am I doing this correctly?  Is the drift in DEC that I observed actually corrected by adjusting the azimuth?  I was surprised that APPM was not able to correct this small error, which means polar alignment must be very accurate to do long period unguided imaging.

Craig





Re: APPC RA rate

Roland Christen
 

You can make the RA drift either slower or faster by raising or lowering the altitude axis. There is a point where the drift rate at the zenith is exactly zero. The RA will of course drift slightly as you move away from the zenith in any direction, and this is caused by the well-known atmospheric refraction effect. Thus there is no one setting of RA tracking rate that works everywhere in the sky, but can work nicely within +- 1 to 2 hours from the zenith.

Rolando



-----Original Message-----
From: craig.young.m8@... [ap-gto]
To: ap-gto
Sent: Fri, Aug 25, 2017 1:27 am
Subject: RE: [ap-gto] APPC RA rate



Hi Howard,

I am not familiar with using a star at the zenith for altitude adjustment.  Can you point me to a reference on how this is done.  For instance, how sensitive is the method to selecting a star that is not exactly at the zenith.  Or, can plate solving be used to determine the drift, e.g., move the scope to HA -10 minutes, take an image and solve, then 10 minutes later another image and solve, measure the drift, adjust the altitude and repeat as necessary.

And a quick note, I did get some clear weather last night and did a 30 point APPM model of the eastern sky.  I then used APPM model to set the tracking and it worked very well.  Previously, with the altitude off by a couple of degrees, the APPM model did not work for tracking, so it appears to be sensitive to this.  With the new alignment it works much better.  So the emphasis now is to tighten up the alignment to less than an arc minute in both axis.

Craig


Re: Luminos control of AP1100

Alan Agrawal <alancygnusx1@...>
 

Hi Roland,

Thank you for making these points.  I am coming from an alt-az world and for years used Polaris as one of my two alignment stars for the Argo Navis on my 24" Starstructure.  A clear case of serious user error to use it for alignment on a GEM :)

I have been successful now in getting  Luminos to work.  The goto now gets somewhat close to the target even with crude polar alignment.  Should be receiving your RAPAS this week, which will   improve accuracy.

A big thank you for putting out all this amazing equipment for us amateurs to use!  You could easily just make stuff for the professional world.

Best,

Alan



On Aug 28, 2017, at 2:09 PM, chris1011@... [ap-gto] <ap-gto@...> wrote:

 

Try not to sync on Polaris at start. You could be off by 3 to 4 hours in RA and still have Polaris in the eyepiece field. That is a recipe for a poor starting point. Start your mount well away from the pole as a first point of reference.


Rolando


-----Original Message-----
From: alancygnusx1@... [ap-gto] <ap-gto@...>
To: ap-gto <ap-gto@...>
Sent: Sat, Aug 19, 2017 12:45 am
Subject: [ap-gto] Luminos control of AP1100



Hi,

I just purchased an AP1100 mount for my TEC 180 FL (visual use for now), and some of my smaller scopes (eg TAK TOA 130 and Mewlon 210).

Although I have some AP accessories, like the excellent diagonal and 2x barlow, this is my first serious piece of AP equipment.

Well, I have to say the quality of the design and build of the 1100  is incredible.  I have the mount assembled now and was able to find one spot on my deck for the mount from which I can see Polaris.    The RAPAS was not available when I ordered, and mine will be arriving in September.  I have Polaris centered in the eyepiece of the scope (using a 12mm reticle eyepiece) with the RA and DEC axes set in a neutral (notches aligned on mount) position.

I want to run the mount from my planetarium software, and don't have the keypad.  I already have Sky Safari Pro, and just purchased Luminos as I read it may have be tter mount controls.

I initialized the mount with the PulseGuide software using the serial cable.  I have been able to successfully connect Luminos to the mount.  So that I don't crash my longer TEC 180 to start with, I have my Mewlon 210  (an amazing scope BTW) mounted.  Using Luminos I can manually slew, which is good.  The problem is using goto.  I have been syncing on Polaris, and then selecting an object to goto, and the mount will slew... but ends up nowhere near the object selected.  Obviously either some fields on the Pulseguide software or in Luminos are incorrect or incomplete, and the mount is completely disoriented.   I do have my location and time correctly in both the Pulseguide software and in Luminos.  This is my 3rd night out now,and now feel I need help from someone experienced.  

Any set of set up tips or trouble shooting advice to get Luminos working is greatly appreci ated.

Best,

Alan





Re: APPC RA rate

Roland Christen
 

The RA will drift if the altitude axis is too high or too low. That is basic polar alignment. The gears and the encoders are dead nuts accurate and are not the cause of any RA drift. Do your RA drift align near the zenith by adjusting the altitude axis until the drift is zero.

Rolando



-----Original Message-----
From: craig.young.m8@... [ap-gto]
To: ap-gto
Sent: Wed, Aug 23, 2017 8:49 pm
Subject: RE: [ap-gto] APPC RA rate



Hi Howard,

That was one of the first tests I did was to see if the RA correction was valid for other parts of the sky.  So far I have only tried in the Eastern side of the sky, but so far the correction is consistent at all hour angles and declinations.  If it was not consistent then the RA correction would be based on some other misalignment but should vary plus or minus.  But that it is consistent and always -0.00100 may point to a problem with the encoder rate or the master clock rate.  I can now do 10 minute unguided imaging in any part of the Eastern sky with nice round stars.  If I turn off the correction, or more often, forget to enable it, then I get elongated stars, always in RA direction and always the same (drive is running too fast).

In refining the polar alignment, using TPoint in SkyX, the azimuth was perfect, 0" error.  But altitude was off by 2 degrees.  I finally got this down to under an arcminute and all works much better.  So far I have not used APPM because of the inconsistencies in the past between the model rates and the actual rates required to track the stars accurately, but tonight, weather permitting, I will do an APPM model again and see if it is any better now.

If that doesn't work I will try your suggestion of setting the rate in both APCC and V2 ASCOM driver.  Hopefully it is persistent so each night I do not have to keep reentering it.

Craig


Re: Luminos control of AP1100

Roland Christen
 

Try not to sync on Polaris at start. You could be off by 3 to 4 hours in RA and still have Polaris in the eyepiece field. That is a recipe for a poor starting point. Start your mount well away from the pole as a first point of reference.

Rolando


-----Original Message-----
From: alancygnusx1@... [ap-gto]
To: ap-gto
Sent: Sat, Aug 19, 2017 12:45 am
Subject: [ap-gto] Luminos control of AP1100



Hi,

I just purchased an AP1100 mount for my TEC 180 FL (visual use for now), and some of my smaller scopes (eg TAK TOA 130 and Mewlon 210).

Although I have some AP accessories, like the excellent diagonal and 2x barlow, this is my first serious piece of AP equipment.

Well, I have to say the quality of the design and build of the 1100  is incredible.  I have the mount assembled now and was able to find one spot on my deck for the mount from which I can see Polaris.    The RAPAS was not available when I ordered, and mine will be arriving in September.  I have Polaris centered in the eyepiece of the scope (using a 12mm reticle eyepiece) with the RA and DEC axes set in a neutral (notches aligned on mount) position.

I want to run the mount from my planetarium software, and don't have the keypad.  I already have Sky Safari Pro, and just purchased Luminos as I read it may have be tter mount controls.

I initialized the mount with the PulseGuide software using the serial cable.  I have been able to successfully connect Luminos to the mount.  So that I don't crash my longer TEC 180 to start with, I have my Mewlon 210  (an amazing scope BTW) mounted.  Using Luminos I can manually slew, which is good.  The problem is using goto.  I have been syncing on Polaris, and then selecting an object to goto, and the mount will slew... but ends up nowhere near the object selected.  Obviously either some fields on the Pulseguide software or in Luminos are incorrect or incomplete, and the mount is completely disoriented.   I do have my location and time correctly in both the Pulseguide software and in Luminos.  This is my 3rd night out now,and now feel I need help from someone experienced.  

Any set of set up tips or trouble shooting advice to get Luminos working is greatly appreci ated.

Best,

Alan





Re: 1600gto dec gears "singing"

Roland Christen
 

Throw a bit of grease onto the spur gears and see if that helps. Lubriplate works nicely.

Rolando



-----Original Message-----
From: john astro@... [ap-gto]
To: ap-gto
Sent: Fri, Aug 18, 2017 4:42 pm
Subject: [ap-gto] 1600gto dec gears "singing"

Hi,

I've just done the prescribed gear mesh adjustments on my 1600GTO mount
which is about 3 years old. After storage and some shipping shakeups,
there was sone backlash. The adjustments worked fine from a backlash
perspective, but my dec axis has developed a metallic singing sound
which I expect is the worm gear resonating(?) maybe.......

Since the ringing only occurs in the final 20 degrees as the scope lays
down into park4, I thought it might be a balance issue, however, as I
apply more or less weight by hand, the sound does not change. I've
obviously adjusted this noise into existence...I'm wondering if this a
known issue and if there is guidance available to an adjustment that
satisfies the backlash needs AND doesn't create unusual noises. In my
limited experience, shrieking and howling gear trains are not a good
thing........

many thanks

John Collins

__________________________



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Re: Mach1 dec gear box backlash spec

Roland Christen
 


Anything under 1 second is normal for the spur gear. Guiding and calibration should always be done at 1x. The slower rates are for manual guiding only.

Rolando



-----Original Message-----
From: rusanovsadi@... [ap-gto]
To: ap-gto
Sent: Wed, Aug 16, 2017 5:57 am
Subject: [ap-gto] Mach1 dec gear box backlash spec



Hi Everyone,

Is there a spec for Mach1 dec gear box backlash in arc secs or time delay at 1x guide rate?

I am trying to understand if the backlash I experience can be reduced by any means.

The worm gear to worm wheel mesh is good, the backlash I see comes from spur gear box. The total time delay from the fastest gear to the gear on the worm gear shaft is 0.8 sec at 1x guide rate. Mostly the delay comes from the spur gear on  the worm gear shaft to the foremost spur gear transition (0.6 seconds).

Is that too much and an indication of a mechanical problem?

 Thanks!




Re: GTO1100 CP4: RA Limits issue

T. Hellwing <t.hellwing@...>
 

Any Ideas?

I know that especially Ray was busy with "hard stuff" from Italy! ;-)

Regards
Thomas

Am 28.08.2017 um 16:30 schrieb 'T. Hellwing' t.hellwing@... [ap-gto] <ap-gto@...>:

 

Hi Ray,

I want to set 3 hours in right ascension past the Meridian.

Regards
Thomas

> Am 28.08.2017 um 16:21 schrieb 'Ray Gralak (Groups)' groups3@... [ap-gto] <ap-gto@...>:
>
> 180 minutes is 3 hours in right ascension


Re : RE: Home position

Yves Laroche
 


Re: Home position

dave@...
 

Lets not go there.

Dave


Re: Home position

dave@...
 

I post from my iPhone and it cuts off my post.

Trolls and Golum came from the same place. deep in middle earth.


Re: Home position

dave@...
 

No, no troll. just someone trying to figure out their mount and compared to their long use mount, have some questions, concerns and is comparing the 2.

If I recall, I can bring up the posts, from just a few months ago, from someone having similar issues. complaining and whining about the differences between their new ap mount compared to there old mass produced mount and sgp. i could but why? that would be some trolling.

I have a 10micron and ap mount. both mounts permanent. I have no issues unparking my ap mount, tell it to go somewhere and the object is in the fov wothin a few arcsec. platesolve, rcal and go. I do the exact same thing with my 10micron. different slews to different parts of the sky will be plate solved and rcal'ed/sync refined. I guide both mounts and use pointing models on both mounts.

PS, 3000 and 4000 10micron mounts have through the mount cabling. An APmount with encoders is comparable in price to the same class 10micron. i've used both mounts, with and without encoders for ap, extensively in my backyard and remotely in NM for years. I think i have a unique perspective from both sides.

A troll and Golum came from the same place. deep in middle


Re: Home position

Worsel
 

GC

I have an A-P 1100.  I originally had the CP3,.  I upgraded to CP4.  The following observations apply to both.

I can do the functions you list using the free A-P ASCOM driver and the free AstroTortilla software for plate solving.  I was away for 10 days.  When I powered up the system, the mount was within 10 arc-minutes of where I wanted it after the initial slew.

Do you have a permanent installation?  If so, then good polar alignment should already be done, regardless of the mount.

While I use other software as well for various function, none of them are necessary to meet the criteria you list below.

Bryan


---In ap-gto@..., <gc.iaffaldano@...> wrote :

No i am not a troll, i am an astroimager who owns both mounts; My opinion is for a better use of AP mount; I'm interested to unpark, to park, to have and keep a good pole alignment with a good sky model; All the other less useful things do not interest me, the things that are still to do ACP make.
Best regards.


Re: Home position

Christopher Erickson
 

GC, to best help you and answer your questions, what model AP mount do you have, which model servo controller and have you tried the free trial of APCC?


-Christopher Erickson
Observatory engineer
Waikoloa, HI 96738
www.summitkinetics.com
   

On Aug 28, 2017 9:07 AM, "gc.iaffaldano@... [ap-gto]" <ap-gto@...> wrote:


No i am not a troll, i am an astroimager who owns both mounts; My opinion is for a better use of AP mount; I'm interested to unpark, to park, to have and keep a good pole alignment with a good sky model; All the other less useful things do not interest me, the things that are still to do ACP make.
Best regards.





Re: Home position

Carmine Iaffaldano
 

No i am not a troll, i am an astroimager who owns both mounts; My opinion is for a better use of AP mount; I'm interested to unpark, to park, to have and keep a good pole alignment with a good sky model; All the other less useful things do not interest me, the things that are still to do ACP make.
Best regards.


Re: GTO1100 CP4: RA Limits issue

T. Hellwing <t.hellwing@...>
 

Hi Ray,

I want to set 3 hours in right ascension past the Meridian.

Regards
Thomas

Am 28.08.2017 um 16:21 schrieb 'Ray Gralak (Groups)' groups3@... [ap-gto] <ap-gto@...>:

180 minutes is 3 hours in right ascension


Re: GTO1100 CP4: RA Limits issue

Ray Gralak
 

Hi Thomas,

180 minutes is 3 hours in right ascension. Is that what you meant to set?

Or did you want to set it to 180 arc-minutes? (12 minutes RA past the meridian).

Best regards,

-Ray Gralak
Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc
Author of PEMPro: http://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver
Author of PulseGuide: http://www.pulseguide.com
Author of Sigma: http://www.gralak.com/sigma

-----Original Message-----
From: ap-gto@... [mailto:ap-gto@...]
Sent: Monday, August 28, 2017 5:53 AM
To: ap-gto@...
Subject: [ap-gto] GTO1100 CP4: RA Limits issue



Hello to all,
I tried to set the RA limits at the Homing/Limits Tab but APCC pro ignore these setting (180 min.) and my
Telescope almost crashed into the pier.
Is there something I have to amend as well?

KR
Thomas




GTO1100 CP4: RA Limits issue

t.hellwing@...
 

Hello to all,
I tried to set the RA limits at the Homing/Limits Tab but APCC pro ignore these setting (180 min.) and my Telescope almost crashed into the pier.
Is there something I have to amend as well?

KR
Thomas


APCC site vs. AP-V2 site

Stelios
 

I installed AP-V2 *before* I bought APCC. I set up my sites  there. 


Then later, when I bought APCC, I installed my sites *there*. As I first fire-up APCC, that's where I change my site location.


However, I notice that AP-V2 does *not* inherit that information from APCC (I can see how that would be difficult) and displays as my site the 'wrong' one. It shows coordinates from site location and from mount (which are different.


My question is: Does this cause any problem? It doesn't seem to, but as it's AP-V2 which communicates with other software, I wonder if it would affect things like plate-solving (although that, too, seems to work great, within 1 pixel in two slews) etc. 


Incidentally, it *would* be great if the AP-V2 driver would get info from APCC when that's up and running. Something to work on on idle nights... 


Re: Home position

Stelios
 

10-Micron troll (ok, partisano) certainly came to my mind...

Actually I've seen very few "problems" discussed here. There are many questions for clarification, but few real problems. Usually those are quickly referred to support and taken care of. 

I don't know what can be so difficult or confusing about APCC. I bought (after vacillating for a while) the Standard version. It is, as it says, a control center. I can immediately set my location, change unpark positions, configure limits, etc, plus it provides me with a great slew-stop security blanket :-). But most of the time, here's what I do for an imaging session (and I strongly suspect the below could be simplified).

Fire up APCC.
Click on site (if changing sites).
Click on connect (I have it to auto-initialize)
Click on connect for the AP-V2 driver.
Minimize and fire up SGP (which automatically fires up PhD2 as needed unless for some reason you want to recalibrate). 
Do your imaging.
At conclusion, I disconnect from SGP.
I maximize APCC and park (I believe that could've been done from SGP as well, but haven't done so yet).
I disconnect (two clicks) and close. 

Now maybe this is all easier with 10 Micron, but I know that somehow I'm imaging *way* before the 10-Micron users in our club. As for polar alignment try Sharpcap. Yes, another software--and how does that hurt? 

I'm *not* putting down 10 Micron, a beautiful, clever (and *pricey* and heavy and lacking through-mount-cabling) mount which is a great solution if for some reason you *must* image unguided. But let's not invent non-existent issues. 

And as for integrated software, I see no reason when Stellarium and Cartes Du Ciel are free. What exactly does something like TheSky do for you? At least APCC will let you track asteroids and satellites via the Horizons module (which I should find to try someday...).