Mount is "lost"


Michael Hamburg
 

I am the 2nd owner of an AP900 that is permanently mounted in my observatory. When I got it I did a preliminary PA, 2-star calibration, and then a Quick Drift Meridian Delay. First session imaging seemed to go well. I use the hand controller which I initialized as per instructions. The only external program connected to the mount is PHD2. After a too long hiatus, the next session was a disaster. The mount wouldn't point in the correct spot- all the GoTos were way off. Last weekend I tried to recalibrate startingfrom the Park 3 position using the 2- star method. I could get the scope to get close to the 2nd star, but when slewing back to the 1st star it was off. I went back and forth. (In this case between Arcturus and Spica.) I faithfully followed the instructions in the manual but too no avail. Then theclouds came. I must be doing something very wrong. I would appreciate any and all help. (One of my hurdles is that I am 160 miles from my observatory during the week but here in Brooklyn, the internet is great. At the western MA site, the internet stinks so it is difficult to communicate on site.) Thanks again.


Roland Christen
 

I believe you have 2 issues which you may not be understanding.

1st issue is "Mount is lost". This can happen for a number of reasons, but you can recover by simply sending the mount to one of the park positions. If the mount ends up being off from that position, simply loosen the clutches and physically move the mount until it is in the correct position.

2nd issue - being off when slewing from one star to another is not an indication that the mount is lost. I'm not sure of what methods you are using for polar alignment, but if your slews are off it is an indication that your polar alignment is off. Doing polar alignment using the quick Drift alignment or 2 star alignment is only approximate and works for short focal length wide field scopes. When you have substantial focal length scopes, such as your SCT, then mount polar alignment has to be much more accurately done in order to get any kind of pointing accuracy. If you are off by 1 degree in a wide-field refractor, the object would probably be in the field, but with a long focus SCT it would not appear. That does not mean that the mount is lost, or that you have done something very wrong.

Pointing a long scope very accurately requires excellent polar alignment, but even that is not enough. The sky itself is not uniform due to atmospheric refraction. SCTs can have mirror flop which causes star positions to be misplaced due to gravity from one part of the sky to another. Then there is the issue of optical and mechanical orthogonality when going from one side of the sky to another.

All these things can add up, but the largest contributor to poor pointing is polar misalignment. There are a number of tools available, software and hardware, that can point your polar axis very accurately to the NCP. Since you have a permanent setup, that only has to be done once. I recommend drift alignment using PEMPro. With this program you have a number of tools that will not only get your mount properly polar aligned, but also will spiff up your tracking accuracy. Very useful tool.

Rolando



-----Original Message-----
From: Michael Hamburg via groups.io <michael_hamburg44@...>
To: main@ap-gto.groups.io
Sent: Wed, Jun 3, 2020 10:06 am
Subject: [ap-gto] Mount is "lost"

I am the 2nd owner of an AP900 that is permanently mounted in my observatory. When I got it I did a preliminary PA, 2-star calibration, and then a Quick Drift Meridian Delay. First session imaging seemed to go well. I use the hand controller which I initialized as per instructions. The only external program connected to the mount is PHD2. After a too long hiatus, the next session was a disaster. The mount wouldn't point in the correct spot- all the GoTos were way off. Last weekend I tried to recalibrate startingfrom the Park 3 position using the 2- star method. I could get the scope to get close to the 2nd star, but when slewing back to the 1st star it was off. I went back and forth. (In this case between Arcturus and Spica.) I faithfully followed the instructions in the manual but too no avail. Then theclouds came. I must be doing something very wrong. I would appreciate any and all help. (One of my hurdles is that I am 160 miles from my observatory during the week but here in Brooklyn, the internet is great. At the western MA site, the internet stinks so it is difficult to communicate on site.) Thanks again.


Jodi McCullough
 

George at AP is a big help.  I suspect the battery in the hand paddle is bad.  We had to replace the wired in one then it was fine.  Gave us similar problems.


On Jun 3, 2020, at 11:10 AM, Michael Hamburg via groups.io <michael_hamburg44@...> wrote:

I am the 2nd owner of an AP900 that is permanently mounted in my observatory. When I got it I did a preliminary PA, 2-star calibration, and then a Quick Drift Meridian Delay. First session imaging seemed to go well. I use the hand controller which I initialized as per instructions. The only external program connected to the mount is PHD2. After a too long hiatus, the next session was a disaster. The mount wouldn't point in the correct spot- all the GoTos were way off. Last weekend I tried to recalibrate startingfrom the Park 3 position using the 2- star method. I could get the scope to get close to the 2nd star, but when slewing back to the 1st star it was off. I went back and forth. (In this case between Arcturus and Spica.) I faithfully followed the instructions in the manual but too no avail. Then theclouds came. I must be doing something very wrong. I would appreciate any and all help. (One of my hurdles is that I am 160 miles from my observatory during the week but here in Brooklyn, the internet is great. At the western MA site, the internet stinks so it is difficult to communicate on site.) Thanks again.<20200529_165904.jpg>


Roland Christen
 

I don't believe the battery is bad. If the stars are close and off just a small amount, it points to a poor misalign. If the battery is bad, you will get no pointing whatsoever, all data is scrambled and the mount will not go anywhere even close.

Rolando



-----Original Message-----
From: Jodi McCullough <jmccul@...>
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Sent: Wed, Jun 3, 2020 11:34 am
Subject: Re: [ap-gto] Mount is "lost"

George at AP is a big help.  I suspect the battery in the hand paddle is bad.  We had to replace the wired in one then it was fine.  Gave us similar problems.


On Jun 3, 2020, at 11:10 AM, Michael Hamburg via groups.io <michael_hamburg44@...> wrote:

I am the 2nd owner of an AP900 that is permanently mounted in my observatory. When I got it I did a preliminary PA, 2-star calibration, and then a Quick Drift Meridian Delay. First session imaging seemed to go well. I use the hand controller which I initialized as per instructions. The only external program connected to the mount is PHD2. After a too long hiatus, the next session was a disaster. The mount wouldn't point in the correct spot- all the GoTos were way off. Last weekend I tried to recalibrate startingfrom the Park 3 position using the 2- star method. I could get the scope to get close to the 2nd star, but when slewing back to the 1st star it was off. I went back and forth. (In this case between Arcturus and Spica.) I faithfully followed the instructions in the manual but too no avail. Then theclouds came. I must be doing something very wrong. I would appreciate any and all help. (One of my hurdles is that I am 160 miles from my observatory during the week but here in Brooklyn, the internet is great. At the western MA site, the internet stinks so it is difficult to communicate on site.) Thanks again.<20200529_165904.jpg>


Dale Ghent
 

You have a photography setup, so why not just skip over messing with star syncs and just do a plate solve + sync using whichever astrophotography app that you employ?

/dale

On Jun 3, 2020, at 11:06 AM, Michael Hamburg via groups.io <michael_hamburg44=yahoo.com@groups.io> wrote:

I am the 2nd owner of an AP900 that is permanently mounted in my observatory. When I got it I did a preliminary PA, 2-star calibration, and then a Quick Drift Meridian Delay. First session imaging seemed to go well. I use the hand controller which I initialized as per instructions. The only external program connected to the mount is PHD2. After a too long hiatus, the next session was a disaster. The mount wouldn't point in the correct spot- all the GoTos were way off. Last weekend I tried to recalibrate startingfrom the Park 3 position using the 2- star method. I could get the scope to get close to the 2nd star, but when slewing back to the 1st star it was off. I went back and forth. (In this case between Arcturus and Spica.) I faithfully followed the instructions in the manual but too no avail. Then theclouds came. I must be doing something very wrong. I would appreciate any and all help. (One of my hurdles is that I am 160 miles from my observatory during the week but here in Brooklyn, the internet is great. At the western MA site, the internet stinks so it is difficult to communicate on site.) Thanks again.<20200529_165904.jpg>


Steven Panish
 

First thing is to get good polar alignment, as Roland says.  I find the quickest method is in SharpCap Pro ($15/yr).  Very easy to use and unaffected by orthogonality error.

Steve

On Wed, Jun 3, 2020 at 1:47 PM Dale Ghent <daleg@...> wrote:

You have a photography setup, so why not just skip over messing with star syncs and just do a plate solve + sync using whichever astrophotography app that you employ?

/dale

> On Jun 3, 2020, at 11:06 AM, Michael Hamburg via groups.io <michael_hamburg44=yahoo.com@groups.io> wrote:
>
> I am the 2nd owner of an AP900 that is permanently mounted in my observatory. When I got it I did a preliminary PA, 2-star calibration, and then a Quick Drift Meridian Delay. First session imaging seemed to go well. I use the hand controller which I initialized as per instructions. The only external program connected to the mount is PHD2. After a too long hiatus, the next session was a disaster. The mount wouldn't point in the correct spot- all the GoTos were way off. Last weekend I tried to recalibrate startingfrom the Park 3 position using the 2- star method. I could get the scope to get close to the 2nd star, but when slewing back to the 1st star it was off. I went back and forth. (In this case between Arcturus and Spica.) I faithfully followed the instructions in the manual but too no avail. Then theclouds came. I must be doing something very wrong. I would appreciate any and all help. (One of my hurdles is that I am 160 miles from my observatory during the week but here in Brooklyn, the internet is great. At the western MA site, the internet stinks so it is difficult to communicate on site.) Thanks again.<20200529_165904.jpg>
>





Michael Hamburg
 

Thanks for the replies. SharpCap seems intriguing; however, it only works with certain cameras not DSLRs. I have a Lodestar hooked up to an OAG for my Edge 11HD - way too long a focal length. My imaging camera is a Canon 6D.  My finder scope is a Celestron 9 X 50mm RACI. I don't think I can use SharpCap with that. There is Astrotortilla, but I haven't learned how to use that. I may be able to use PHD2's drift align, but it all seems a bit daunting.
 
Best wishes, Michael


On Wednesday, June 3, 2020, 03:21:27 PM EDT, Steven Panish <scpanish@...> wrote:


First thing is to get good polar alignment, as Roland says.  I find the quickest method is in SharpCap Pro ($15/yr).  Very easy to use and unaffected by orthogonality error.

Steve

On Wed, Jun 3, 2020 at 1:47 PM Dale Ghent <daleg@...> wrote:

You have a photography setup, so why not just skip over messing with star syncs and just do a plate solve + sync using whichever astrophotography app that you employ?

/dale

> On Jun 3, 2020, at 11:06 AM, Michael Hamburg via groups.io <michael_hamburg44=yahoo.com@groups.io> wrote:
>
> I am the 2nd owner of an AP900 that is permanently mounted in my observatory. When I got it I did a preliminary PA, 2-star calibration, and then a Quick Drift Meridian Delay. First session imaging seemed to go well. I use the hand controller which I initialized as per instructions. The only external program connected to the mount is PHD2. After a too long hiatus, the next session was a disaster. The mount wouldn't point in the correct spot- all the GoTos were way off. Last weekend I tried to recalibrate startingfrom the Park 3 position using the 2- star method. I could get the scope to get close to the 2nd star, but when slewing back to the 1st star it was off. I went back and forth. (In this case between Arcturus and Spica.) I faithfully followed the instructions in the manual but too no avail. Then theclouds came. I must be doing something very wrong. I would appreciate any and all help. (One of my hurdles is that I am 160 miles from my observatory during the week but here in Brooklyn, the internet is great. At the western MA site, the internet stinks so it is difficult to communicate on site.) Thanks again.<20200529_165904.jpg>
>





Roland Christen
 

PHD drift align is so easy, even I can do it. It's totally automatic and very intuitive.

Rolando



-----Original Message-----
From: Michael Hamburg via groups.io <michael_hamburg44@...>
To: main@ap-gto.groups.io
Sent: Wed, Jun 3, 2020 5:23 pm
Subject: Re: [ap-gto] Mount is "lost"

Thanks for the replies. SharpCap seems intriguing; however, it only works with certain cameras not DSLRs. I have a Lodestar hooked up to an OAG for my Edge 11HD - way too long a focal length. My imaging camera is a Canon 6D.  My finder scope is a Celestron 9 X 50mm RACI. I don't think I can use SharpCap with that. There is Astrotortilla, but I haven't learned how to use that. I may be able to use PHD2's drift align, but it all seems a bit daunting.
 
Best wishes, Michael


On Wednesday, June 3, 2020, 03:21:27 PM EDT, Steven Panish <scpanish@...> wrote:


First thing is to get good polar alignment, as Roland says.  I find the quickest method is in SharpCap Pro ($15/yr).  Very easy to use and unaffected by orthogonality error.

Steve

On Wed, Jun 3, 2020 at 1:47 PM Dale Ghent <daleg@...> wrote:

You have a photography setup, so why not just skip over messing with star syncs and just do a plate solve + sync using whichever astrophotography app that you employ?

/dale

> On Jun 3, 2020, at 11:06 AM, Michael Hamburg via groups.io <michael_hamburg44=yahoo.com@groups.io> wrote:
>
> I am the 2nd owner of an AP900 that is permanently mounted in my observatory. When I got it I did a preliminary PA, 2-star calibration, and then a Quick Drift Meridian Delay. First session imaging seemed to go well. I use the hand controller which I initialized as per instructions. The only external program connected to the mount is PHD2. After a too long hiatus, the next session was a disaster. The mount wouldn't point in the correct spot- all the GoTos were way off. Last weekend I tried to recalibrate startingfrom the Park 3 position using the 2- star method. I could get the scope to get close to the 2nd star, but when slewing back to the 1st star it was off. I went back and forth. (In this case between Arcturus and Spica.) I faithfully followed the instructions in the manual but too no avail. Then theclouds came. I must be doing something very wrong. I would appreciate any and all help. (One of my hurdles is that I am 160 miles from my observatory during the week but here in Brooklyn, the internet is great. At the western MA site, the internet stinks so it is difficult to communicate on site.) Thanks again.<20200529_165904.jpg>
>





 

you might consider polemaster, it's a couple hundred, but so incredibly simple and will work with your DSLR setup


On Wed, Jun 3, 2020 at 3:23 PM Michael Hamburg via groups.io <michael_hamburg44=yahoo.com@groups.io> wrote:
Thanks for the replies. SharpCap seems intriguing; however, it only works with certain cameras not DSLRs. I have a Lodestar hooked up to an OAG for my Edge 11HD - way too long a focal length. My imaging camera is a Canon 6D.  My finder scope is a Celestron 9 X 50mm RACI. I don't think I can use SharpCap with that. There is Astrotortilla, but I haven't learned how to use that. I may be able to use PHD2's drift align, but it all seems a bit daunting.
 
Best wishes, Michael


On Wednesday, June 3, 2020, 03:21:27 PM EDT, Steven Panish <scpanish@...> wrote:


First thing is to get good polar alignment, as Roland says.  I find the quickest method is in SharpCap Pro ($15/yr).  Very easy to use and unaffected by orthogonality error.

Steve

On Wed, Jun 3, 2020 at 1:47 PM Dale Ghent <daleg@...> wrote:

You have a photography setup, so why not just skip over messing with star syncs and just do a plate solve + sync using whichever astrophotography app that you employ?

/dale

> On Jun 3, 2020, at 11:06 AM, Michael Hamburg via groups.io <michael_hamburg44=yahoo.com@groups.io> wrote:
>
> I am the 2nd owner of an AP900 that is permanently mounted in my observatory. When I got it I did a preliminary PA, 2-star calibration, and then a Quick Drift Meridian Delay. First session imaging seemed to go well. I use the hand controller which I initialized as per instructions. The only external program connected to the mount is PHD2. After a too long hiatus, the next session was a disaster. The mount wouldn't point in the correct spot- all the GoTos were way off. Last weekend I tried to recalibrate startingfrom the Park 3 position using the 2- star method. I could get the scope to get close to the 2nd star, but when slewing back to the 1st star it was off. I went back and forth. (In this case between Arcturus and Spica.) I faithfully followed the instructions in the manual but too no avail. Then theclouds came. I must be doing something very wrong. I would appreciate any and all help. (One of my hurdles is that I am 160 miles from my observatory during the week but here in Brooklyn, the internet is great. At the western MA site, the internet stinks so it is difficult to communicate on site.) Thanks again.<20200529_165904.jpg>
>






--
Brian 



Brian Valente


Christopher Erickson
 

It looks like you have done a careful job with cable management but any new, temporary cable that is snagging on anything can result in the symptoms you describe.

Or maybe despite your best efforts, your umbilical is catching or snagging somehow.

Or thirdly, you have a chain of optical bits stacked on the back of that scope. Any chance that any of the interconnected components is slipping, sagging or shifting? Any loose set/lock/thumb screws anywhere back there?

No mirror shift problems? Are you using the mirror locks or is the primary unlocked? I can't tell for sure if you have an electronic focuser in that optical stack in the back.

Are your secondary collimation screws snug? No unstable secondary mirror issues?

I hope this helps.


On Wed, Jun 3, 2020 at 5:09 AM Michael Hamburg via groups.io <michael_hamburg44=yahoo.com@groups.io> wrote:
I am the 2nd owner of an AP900 that is permanently mounted in my observatory. When I got it I did a preliminary PA, 2-star calibration, and then a Quick Drift Meridian Delay. First session imaging seemed to go well. I use the hand controller which I initialized as per instructions. The only external program connected to the mount is PHD2. After a too long hiatus, the next session was a disaster. The mount wouldn't point in the correct spot- all the GoTos were way off. Last weekend I tried to recalibrate startingfrom the Park 3 position using the 2- star method. I could get the scope to get close to the 2nd star, but when slewing back to the 1st star it was off. I went back and forth. (In this case between Arcturus and Spica.) I faithfully followed the instructions in the manual but too no avail. Then theclouds came. I must be doing something very wrong. I would appreciate any and all help. (One of my hurdles is that I am 160 miles from my observatory during the week but here in Brooklyn, the internet is great. At the western MA site, the internet stinks so it is difficult to communicate on site.) Thanks again.


willsonjared
 

I suspect your mount initially got “lost” because of the differences between a sync and a recal.  You mentioned using the meridian delay function. This is where people occasionally get into trouble on the differences between the two. Look through the user manual—I seem to recall it does a good job of explaining the difference and how to use them effectively.

As to the current pointing issues... You have a lot of focal length in your SCT, a movable primary mirror, and it sounds like you have not yet done a careful polar alignment. I would start there—doing the careful polar alignment. It won’t change the fact that you have a movable primary and a lot of focal length, but it will improve things. 

Long term, though, you may always have challenges with pointing accuracy. Between the focal length (which results in a small field of view), atmospheric refraction, mechanical imperfections in the mount, flexure, and, especially, the shifting primary it may not be possible for slews to always put your subject in the field of view.  You could look at building a solid pointing model using APCC Pro (not free), but you would need some way to do plate solves, and I’m not sure that is possible with a DSLR. Someone else may have relevant experience on that. Were you planning on sticking with the SLR?


Michael Hamburg
 

Thanks for the reply. So far I have been happy with my Canon 6D.

Best wishes, Michael


On Thursday, June 4, 2020, 01:54:27 PM EDT, willsonjared via groups.io <willsonjared@...> wrote:


I suspect your mount initially got “lost” because of the differences between a sync and a recal.  You mentioned using the meridian delay function. This is where people occasionally get into trouble on the differences between the two. Look through the user manual—I seem to recall it does a good job of explaining the difference and how to use them effectively.

As to the current pointing issues... You have a lot of focal length in your SCT, a movable primary mirror, and it sounds like you have not yet done a careful polar alignment. I would start there—doing the careful polar alignment. It won’t change the fact that you have a movable primary and a lot of focal length, but it will improve things. 

Long term, though, you may always have challenges with pointing accuracy. Between the focal length (which results in a small field of view), atmospheric refraction, mechanical imperfections in the mount, flexure, and, especially, the shifting primary it may not be possible for slews to always put your subject in the field of view.  You could look at building a solid pointing model using APCC Pro (not free), but you would need some way to do plate solves, and I’m not sure that is possible with a DSLR. Someone else may have relevant experience on that. Were you planning on sticking with the SLR?


Worsel
 

Michael

I have a 6D on a 2500 mm f.l. scope and AP 1100 - non-AE.  APPM (part of APPC Pro) has no problem building good pointing and tracking models with a DSLR.  APPM does require plate solving, but that is true regardless of the camera.  I use astrometry.net (Local) under SGP.  The 6D is connected via SGP.

SGP function with APPM is to take an image, plate solve, and send image coordinates to APPM.  There are other apps that can do this with APPM, but SGP is the least expensive and many people use it anyway.

See Section 13 in the APPC Pro manual

I learned (likely obvious to most people already) that a good PE correction before APPM is important.  PEMPro V3.  While you can use a DSLR for this via SGP, I used a guide camera, OAG, and Ray's "Enhanced PHD2."

I have been able to do 10-minute unguided images (although not repeatably...still working on that.) with the above...no AE, no HC.

Bryan


Leszek
 

+1 for polemaster.  BTW polemaster will work with sharpcap's polar alignment and that's what I use for my AP900.  It literally takes less than 3 min to be polar aligned with polemaster/sharpcap combo.


 

>>> BTW polemaster will work with sharpcap's polar alignment and that's what I use for my AP900.  It literally takes less than 3 min to be polar aligned with polemaster/sharpcap combo.

interesting!

i will have to try that out.

On Fri, Jun 5, 2020 at 12:00 PM Leszek <leszek@...> wrote:
+1 for polemaster.  BTW polemaster will work with sharpcap's polar alignment and that's what I use for my AP900.  It literally takes less than 3 min to be polar aligned with polemaster/sharpcap combo.



--
Brian 



Brian Valente


Leszek
 

A word of caution though.  Once you try sharpcap with polemaster you will never go back to the QHY polemaster app. :)  I only use the polemaster app on my android phone if I'm in a remote location without my computer.


Bill Long
 

I have only used SharpCap Pro via my main imaging camera, but it does work exceptionally well. Here is a snip of the model properties from APCC on the last model I built using the 1100AE with nothing more than SharpCap Pro alignment. 




From: main@ap-gto.groups.io <main@ap-gto.groups.io> on behalf of Leszek <leszek@...>
Sent: Friday, June 5, 2020 12:47 PM
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Subject: Re: [ap-gto] Mount is "lost"
 
A word of caution though.  Once you try sharpcap with polemaster you will never go back to the QHY polemaster app. :)  I only use the polemaster app on my android phone if I'm in a remote location without my computer.


 

I'm already not going back to the polemaster app!

the main problem i found with polemaster is that it's just not that accurate. around 30 arcsec but with my main camera/ota and sharpcap i can usually get 5-10arcsec

On Fri, Jun 5, 2020 at 12:47 PM Leszek <leszek@...> wrote:
A word of caution though.  Once you try sharpcap with polemaster you will never go back to the QHY polemaster app. :)  I only use the polemaster app on my android phone if I'm in a remote location without my computer.



--
Brian 



Brian Valente


Peter Nagy
 

I also use Sharp Cap Pro with PoleMaster. The software just could not be any easier!!!!!

https://peternagy.smugmug.com/Telescopes/PoleMaster-on-A-P1100GTO/

My mount is the first run of A-P1100GTO. The two placeholder bolts were part of the motor gear box. Newer mounts do not have placeholder bolts anymore.

Peter


Leszek
 

The nice part about AP900 and Mach2 is the fact that you can order the polemaster with the AP adaper that allows you to screw it in directly into the mount (picture from AP web site)