Date   

moderated Re: Setting up at Fremont Peak, California

dvjbaja
 

That was supposed to have had a photo with it. Oops. 



Sent via the Samsung Galaxy Note9, an AT&T 5G Evolution capable smartphone


-------- Original message --------
From: "KHursh via groups.io" <khursh@...>
Date: 1/23/21 4:10 PM (GMT-08:00)
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Setting up at Fremont Peak, California

I used to go there all the time when I was in the south bay. Great viewing especially when the fog rolls in to cover Salinas and Hollister.

Clear skies!


Re: Mach2 - Imaging in frigid night

Roland Christen
 

:RT8# is the command that starts the King rate. It will be in upcoming APCC and ASCOM driver updates.

Rolando



-----Original Message-----
From: Jim Fakatselis <pashasdad@...>
To: main@ap-gto.groups.io
Sent: Sat, Jan 23, 2021 11:15 pm
Subject: Re: [ap-gto] Mach2 - Imaging in frigid night

Excellent explanation.  I appreciate the tutorial.  
Would be interested in the CP4,5 command later on.  

Thank you,
Jim


On Jan 23, 2021, at 3:59 PM, Roland Christen via groups.io <chris1011@...> wrote:


The King rate is not based on a model. It is a calculated custom rate that is created inside the CP4/CP5 controller and is accessed thru a simple command, similar to what you would send to get Lunar or Solar rate. Although Sidereal, Lunar and Solar rates are fixed rates, the King rate is a variable rate. The rate is calculated inside the CP controller and depends on the position in the sky. The rate is accessed via a simple command sent to the mount from the keypad and I believe from APCC (although I don't know for sure). I don't remember the command right now but can get it from our tech guys on Monday.

The equation for the King rate works for most of the sky until you come close to the horizon, at which point it is limited. Here is a primer of what the King rate does:
https://canburytech.net/DriftAlign/DriftAlign_3.html

This one allows you to compare King and Sidereal rates for any point in the sky:
http://www.bbastrodesigns.com/equatTrackingRatesCalc.html

I do want to point out that this does not compensate for polar misalignment and Dec drift. Dec drift is normally a small fraction of RA drift, and it can be mostly nulled out by proper alignment of the azimuth axis. In the case where I was shooting down low in the east to image the Rosette early on, the RA drift rate was around 30 arc sec per hour, the Dec drift was only 5. If you're going to guide, it is nice to have the RA rate close to what is actually happening in the sky so that the guider is loafing along.

If you want to do unguided, then you can do a quick model of the path that the object will follow. 5 or 6 points will do nicely. In my case I'm taking 20 minute exposures at 1200mm focal length and I wanted to see how well the system guides at 1200mm on a bitter cold night, with about 70lb of scope and equipment attached.

Rolando



-----Original Message-----
From: Jim Fakatselis <pashasdad@...>
To: main@ap-gto.groups.io
Sent: Sat, Jan 23, 2021 2:31 pm
Subject: Re: [ap-gto] Mach2 - Imaging in frigid night

So there is no easy selection for King rate without a model?
Is this perhaps a possible opportunity to add it as an option button in APCC?

Jim


On Jan 23, 2021, at 12:10 PM, Roland Christen via groups.io <chris1011@...> wrote:


Yes, that is correct.

Roland



-----Original Message-----
From: Worsel via groups.io <bryancashion@...>
To: main@ap-gto.groups.io
Sent: Sat, Jan 23, 2021 10:41 am
Subject: Re: [ap-gto] Mach2 - Imaging in frigid night

Roland

Jim's question prompted a related thought.  I assume there is no need even to bother with King rate, if using an APPM model with MGBox for environmental conditions to correct for refraction.  Is this correct?


TIA

Bryan

--
Roland Christen
Astro-Physics

--
Roland Christen
Astro-Physics

--
Roland Christen
Astro-Physics


Re: Tracking rate keeps reverting to zero

Ray Gralak
 

> The tracking rate in APCC on the 1200 keeps reverting to zero after I set it to sidereal. SGP says wrong tracking

> rate when I attempt to center.

>

> https://www.dropbox.com/s/ju5snz98x0n2tol/ApccZip-Peter_Bresler-2021-01-24-003203.zip?dl=0

 

You configured the mount to stop tracking at the meridian limit:

 

0033646 2021-01-23 23:37:01.904:       Info, Meridian Limits, Limit reached - stopping mount tracking - Dec=8.83611111111111, MeridianAngle=63.5347222222222, Hour Angle=-1.1034482717514

0033647 2021-01-23 23:37:01.905:      Debug,  Command Thread, TX (High Priority) = ':RT9#'

 

You can either reconfigure the Flip Offset in APCC with more time, or enable the option in the ASCOM driver to ignore applications that don’t check and reenable tracking when needed. The option is called “Auto enable tracking…” in The ASCOM Driver’s Setup window in the “Other Options” group box.

 

https://www.gralak.com/apdriver/help/index.html?other_options.htm

 

-Ray Gralak

Author of PEMPro

Author of APCC (Astro-Physics Command Center): https://www.astro-physics.com/apcc-pro

Author of Astro-Physics V2 ASCOM Driver: https://www.siriusimaging.com/apdriver

 

> -----Original Message-----

> From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Peter Bresler via groups.io

> Sent: Sunday, January 24, 2021 12:53 AM

> To: main@ap-gto.groups.io

> Subject: [ap-gto] Tracking rate keeps reverting to zero

>

> The tracking rate in APCC on the 1200 keeps reverting to zero after I set it to sidereal. SGP says wrong tracking

> rate when I attempt to center.

>

> https://www.dropbox.com/s/ju5snz98x0n2tol/ApccZip-Peter_Bresler-2021-01-24-003203.zip?dl=0

>

>


Re: Mach2 - Imaging in frigid night

Pete Mumbower
 

On an iPhone, you can access the Clear Sky Clock via the Safari browser, then hit the icon at the bottom with the arrow coming out of the box, then pick "Add to Home Screen". Then you have a icon on the phone screen that launches the browser based CSC. Works great.


Re: Mach2 - Imaging in frigid night

Roland Christen
 

I access Clear Sky Clock on my desktop computer at work: https://www.cleardarksky.com/c/AstrPhyILkey.html
I think there is a way you can set it up, but you would probably have to contact the author, Attilla Danko. I don't remember how we did it so many years ago. danko@...

Roland



-----Original Message-----
From: Steve C. Mitchell, Sr., O.D. <smitchell@...>
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Sent: Sat, Jan 23, 2021 11:37 pm
Subject: Re: [ap-gto] Mach2 - Imaging in frigid night

Hey Rolando,
 
I know this is a bit off topic for AP stuff and this thread, but since it’s part of your original post and you brought it up! 8>)
 
I used Clear Sky Clock for several years, until it failed to work for me as I worked up higher in the Samsung Galaxy phone line. I believe when I hit the S10 model  is when it quit working for me and I was forced to try other apps, but have always liked it the best. As I go back to the Google Play store now to see if they’ve done an upgrade, it’s not even an option any more. I know it’s a Canadian weatherman that wrote the app and supported it and perhaps you know him so…. Sometimes it’s not what you know, but WHO you know. 8>) And since I see you are still using it, I have a few simple questions.
 
Do you know Allen, the author, and he’s supplying you with a special AP option? (Sweet) 8>)
Have you simply had it a long time and still using an older Android phone and he still supports it?
Or are you using an Apple device and that’s where it’s at now and no longer available for Android us users? (My luck)
 
Inquiring minds want to know.
 
Steve
Proud owner of an 1100 mount for almost a year now. I love to just see and hear it operate in the observatory; in my opinion it is of upmost quality of craftsmanship and approaches a work of art. Best mount I’ve ever had!
 
 
 
On Friday, January 22, 2021, 07:42:18 PM CST, Roland Christen via groups.io <chris1011@...> wrote:
 
 
Hi Astronuts,
 
First clear night in a month, fired up the 160 EDF on the Mach2 mount at the AP observatory. There's also a 155 EDF riding piggyback, but not being used tonight. It's 5 deg F (-15C) right now with very clear air. The temperature is dropping like an anvil off a cliff. Seeing is, well see below (poor - 2 out of 5). The mount is tracking with MaximDL, multi-star tracking mode and averaging 0.15 rms arc sec. This is the first time in a year that I've operated this mount in such cold conditions. My fingers are freezing after only 5 minutes of operating out there. But for clear skies, it's worth it.
 
Shooting the Rosette in Ha with the Moon straight up.
 
Rolando
 

Current forecast for Astro-Physics Clear Sky Chart

--
Roland Christen
Astro-Physics

--
Roland Christen
Astro-Physics

--
Roland Christen
Astro-Physics


Re: Mach2 - Imaging in frigid night

Steve C. Mitchell, Sr., O.D.
 

Hey Rolando,

 

I know this is a bit off topic for AP stuff and this thread, but since it’s part of your original post and you brought it up! 8>)

 

I used Clear Sky Clock for several years, until it failed to work for me as I worked up higher in the Samsung Galaxy phone line. I believe when I hit the S10 model  is when it quit working for me and I was forced to try other apps, but have always liked it the best. As I go back to the Google Play store now to see if they’ve done an upgrade, it’s not even an option any more. I know it’s a Canadian weatherman that wrote the app and supported it and perhaps you know him so…. Sometimes it’s not what you know, but WHO you know. 8>) And since I see you are still using it, I have a few simple questions.

 

Do you know Allen, the author, and he’s supplying you with a special AP option? (Sweet) 8>)

Have you simply had it a long time and still using an older Android phone and he still supports it?

Or are you using an Apple device and that’s where it’s at now and no longer available for Android us users? (My luck)

 

Inquiring minds want to know.

 

Steve

Proud owner of an 1100 mount for almost a year now. I love to just see and hear it operate in the observatory; in my opinion it is of upmost quality of craftsmanship and approaches a work of art. Best mount I’ve ever had!

 

 

 

On Friday, January 22, 2021, 07:42:18 PM CST, Roland Christen via groups.io <chris1011@...> wrote:

 

 

Hi Astronuts,

 

First clear night in a month, fired up the 160 EDF on the Mach2 mount at the AP observatory. There's also a 155 EDF riding piggyback, but not being used tonight. It's 5 deg F (-15C) right now with very clear air. The temperature is dropping like an anvil off a cliff. Seeing is, well see below (poor - 2 out of 5). The mount is tracking with MaximDL, multi-star tracking mode and averaging 0.15 rms arc sec. This is the first time in a year that I've operated this mount in such cold conditions. My fingers are freezing after only 5 minutes of operating out there. But for clear skies, it's worth it.

 

Shooting the Rosette in Ha with the Moon straight up.

 

Rolando

 


Current forecast for Astro-Physics Clear Sky Chart


--
Roland Christen
Astro-Physics


--
Roland Christen
Astro-Physics


Re: Mach2 - Imaging in frigid night

Jim Fakatselis
 

Excellent explanation.  I appreciate the tutorial.  
Would be interested in the CP4,5 command later on.  

Thank you,
Jim


On Jan 23, 2021, at 3:59 PM, Roland Christen via groups.io <chris1011@...> wrote:


The King rate is not based on a model. It is a calculated custom rate that is created inside the CP4/CP5 controller and is accessed thru a simple command, similar to what you would send to get Lunar or Solar rate. Although Sidereal, Lunar and Solar rates are fixed rates, the King rate is a variable rate. The rate is calculated inside the CP controller and depends on the position in the sky. The rate is accessed via a simple command sent to the mount from the keypad and I believe from APCC (although I don't know for sure). I don't remember the command right now but can get it from our tech guys on Monday.

The equation for the King rate works for most of the sky until you come close to the horizon, at which point it is limited. Here is a primer of what the King rate does:
https://canburytech.net/DriftAlign/DriftAlign_3.html

This one allows you to compare King and Sidereal rates for any point in the sky:
http://www.bbastrodesigns.com/equatTrackingRatesCalc.html

I do want to point out that this does not compensate for polar misalignment and Dec drift. Dec drift is normally a small fraction of RA drift, and it can be mostly nulled out by proper alignment of the azimuth axis. In the case where I was shooting down low in the east to image the Rosette early on, the RA drift rate was around 30 arc sec per hour, the Dec drift was only 5. If you're going to guide, it is nice to have the RA rate close to what is actually happening in the sky so that the guider is loafing along.

If you want to do unguided, then you can do a quick model of the path that the object will follow. 5 or 6 points will do nicely. In my case I'm taking 20 minute exposures at 1200mm focal length and I wanted to see how well the system guides at 1200mm on a bitter cold night, with about 70lb of scope and equipment attached.

Rolando



-----Original Message-----
From: Jim Fakatselis <pashasdad@...>
To: main@ap-gto.groups.io
Sent: Sat, Jan 23, 2021 2:31 pm
Subject: Re: [ap-gto] Mach2 - Imaging in frigid night

So there is no easy selection for King rate without a model?
Is this perhaps a possible opportunity to add it as an option button in APCC?

Jim


On Jan 23, 2021, at 12:10 PM, Roland Christen via groups.io <chris1011@...> wrote:


Yes, that is correct.

Roland



-----Original Message-----
From: Worsel via groups.io <bryancashion@...>
To: main@ap-gto.groups.io
Sent: Sat, Jan 23, 2021 10:41 am
Subject: Re: [ap-gto] Mach2 - Imaging in frigid night

Roland

Jim's question prompted a related thought.  I assume there is no need even to bother with King rate, if using an APPM model with MGBox for environmental conditions to correct for refraction.  Is this correct?


TIA

Bryan

--
Roland Christen
Astro-Physics

--
Roland Christen
Astro-Physics


moderated Re: Setting up at Fremont Peak, California

KHursh
 

I used to go there all the time when I was in the south bay. Great viewing especially when the fog rolls in to cover Salinas and Hollister.

Clear skies!


moderated Setting up at Fremont Peak, California

dvjbaja
 

Great night's observing ahead. 

-bs


Re: Ap1200 / TheSkyX jog runaway

Roland Christen
 


You mentioned the APCC buttons.  Are you referring to the ones on the AP hand controller?
There are move buttons in both. I was confused by what you were posting about the Jog function, I mixed it up with the move buttons on SkyX.

Yes, it's supposed to move a certain amount of arc seconds in Jog. I don't know why it would not, that's something the Bisques will have to investigate.

Rolando


-----Original Message-----
From: Allen Gilchrist via groups.io <gilchrist.allen@...>
To: main@ap-gto.groups.io
Sent: Sat, Jan 23, 2021 5:06 pm
Subject: Re: [ap-gto] Ap1200 / TheSkyX jog runaway

Roland,

I think the operation you describe is what the TSX MOVE buttons do.  You first select a rate, 1x, 12x, 64x, etc. and then press the desired direction button.  The mount moves at the selected rate until the button is released.  With the JOG function, you select a distance in arc-seconds or arc-minutes and then press and release the button for the desired direction.  The scope is supposed to move the correct ancular distance and then stop.  Unfortunately, last night, the scope moved and then took off slowly to the southwest.  The star I was trying to center left a streak on the image display.  It took me a moment to realize what was happening.  Rather than try to regain software control, I went out and unplugged the scope power.  I then started everything back up and reconnected.  As a test, I repeated the process with the same result.  This same procedure worked fine with an older version of TSX.  I recently "upgraded" to add camera control functions to replace my old CCDSoft V5 software.  For now, I'll  steer clear of the JOG buttons, but hopefully the guys at Software Bisque will be able to fix the problem. 

You mentioned the APCC buttons.  Are you referring to the ones on the AP hand controller?

Allen  

--
Roland Christen
Astro-Physics


Re: Ap1200 / TheSkyX jog runaway

Worsel
 

Allen

Both APCC and AP Driver have "Move Scope" buttons on the GUI.  See attached.


Bryan


Re: Ap1200 / TheSkyX jog runaway

Allen Gilchrist
 

Roland,

I think the operation you describe is what the TSX MOVE buttons do.  You first select a rate, 1x, 12x, 64x, etc. and then press the desired direction button.  The mount moves at the selected rate until the button is released.  With the JOG function, you select a distance in arc-seconds or arc-minutes and then press and release the button for the desired direction.  The scope is supposed to move the correct ancular distance and then stop.  Unfortunately, last night, the scope moved and then took off slowly to the southwest.  The star I was trying to center left a streak on the image display.  It took me a moment to realize what was happening.  Rather than try to regain software control, I went out and unplugged the scope power.  I then started everything back up and reconnected.  As a test, I repeated the process with the same result.  This same procedure worked fine with an older version of TSX.  I recently "upgraded" to add camera control functions to replace my old CCDSoft V5 software.  For now, I'll  steer clear of the JOG buttons, but hopefully the guys at Software Bisque will be able to fix the problem. 

You mentioned the APCC buttons.  Are you referring to the ones on the AP hand controller?

Allen  


Re: Ap1200 / TheSkyX jog runaway

Roland Christen
 

Jog buttons work like this: Press on the E button and the software sends a MoveEast command. As long as you hold the button down, no other command is sent and there is no traffic between the software and the mount. When you let go of the button, the software in SkyX is supposed to send a STOP command. If that command is not sent for some reason, the mount will continue to move. If you are holding the button down and you yank the USB connection to the mount, there is nothing to tell the mount to stop moving, and it will continue on its path.

If you use APCC buttons instead of SkyX, they will work in a fail-safe manner.

Rolando



-----Original Message-----
From: Allen Gilchrist via groups.io <gilchrist.allen@...>
To: main@ap-gto.groups.io
Sent: Sat, Jan 23, 2021 3:02 pm
Subject: Re: [ap-gto] Ap1200 / TheSkyX jog runaway

This is interesting.  Apparently this issue is not new, nor is it completely resolved.  I experienced the same thing last night.  I'm using the latest TSX Imaging Edition, and tried to use a jog command to center a star on my CCD chip.  The mount ran off to the west.  Interestingly, the motion buttons in the autoguider window and the move buttons in the telescope window of TSX work just fine.  I'm in contact with Software Bisque.  

--
Roland Christen
Astro-Physics


Re: Ap1200 / TheSkyX jog runaway

Allen Gilchrist
 

This is interesting.  Apparently this issue is not new, nor is it completely resolved.  I experienced the same thing last night.  I'm using the latest TSX Imaging Edition, and tried to use a jog command to center a star on my CCD chip.  The mount ran off to the west.  Interestingly, the motion buttons in the autoguider window and the move buttons in the telescope window of TSX work just fine.  I'm in contact with Software Bisque.  


Re: Mach2 - Imaging in frigid night

Roland Christen
 

The King rate is not based on a model. It is a calculated custom rate that is created inside the CP4/CP5 controller and is accessed thru a simple command, similar to what you would send to get Lunar or Solar rate. Although Sidereal, Lunar and Solar rates are fixed rates, the King rate is a variable rate. The rate is calculated inside the CP controller and depends on the position in the sky. The rate is accessed via a simple command sent to the mount from the keypad and I believe from APCC (although I don't know for sure). I don't remember the command right now but can get it from our tech guys on Monday.

The equation for the King rate works for most of the sky until you come close to the horizon, at which point it is limited. Here is a primer of what the King rate does:
https://canburytech.net/DriftAlign/DriftAlign_3.html

This one allows you to compare King and Sidereal rates for any point in the sky:
http://www.bbastrodesigns.com/equatTrackingRatesCalc.html

I do want to point out that this does not compensate for polar misalignment and Dec drift. Dec drift is normally a small fraction of RA drift, and it can be mostly nulled out by proper alignment of the azimuth axis. In the case where I was shooting down low in the east to image the Rosette early on, the RA drift rate was around 30 arc sec per hour, the Dec drift was only 5. If you're going to guide, it is nice to have the RA rate close to what is actually happening in the sky so that the guider is loafing along.

If you want to do unguided, then you can do a quick model of the path that the object will follow. 5 or 6 points will do nicely. In my case I'm taking 20 minute exposures at 1200mm focal length and I wanted to see how well the system guides at 1200mm on a bitter cold night, with about 70lb of scope and equipment attached.

Rolando



-----Original Message-----
From: Jim Fakatselis <pashasdad@...>
To: main@ap-gto.groups.io
Sent: Sat, Jan 23, 2021 2:31 pm
Subject: Re: [ap-gto] Mach2 - Imaging in frigid night

So there is no easy selection for King rate without a model?
Is this perhaps a possible opportunity to add it as an option button in APCC?

Jim


On Jan 23, 2021, at 12:10 PM, Roland Christen via groups.io <chris1011@...> wrote:


Yes, that is correct.

Roland



-----Original Message-----
From: Worsel via groups.io <bryancashion@...>
To: main@ap-gto.groups.io
Sent: Sat, Jan 23, 2021 10:41 am
Subject: Re: [ap-gto] Mach2 - Imaging in frigid night

Roland

Jim's question prompted a related thought.  I assume there is no need even to bother with King rate, if using an APPM model with MGBox for environmental conditions to correct for refraction.  Is this correct?


TIA

Bryan

--
Roland Christen
Astro-Physics

--
Roland Christen
Astro-Physics


Re: Best way to connect power cables in remote observatory

Woody Schlom
 

Eric,

 

I like the fact that each power line in the RIGrunner is individually fused.

 

In my mobile observatory, I use traditional marine (plastic, stainless steel and brass) screw terminals, switches and fuse blocks to move 12v around in the observatory, but then switch to RIG runners as I get near my telescope and video gear.

 

The marine stuff is quite expensive (I use Blue Seas and Marinco – different divisions of the same company), but it’s most definitely made for harsh environments.

 

Woody

 

From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of Eric Claeys
Sent: Friday, January 22, 2021 10:25 PM
To: main@ap-gto.groups.io
Subject: [ap-gto] Best way to connect power cables in remote observatory

 

Prior to finishing my remote observatory I'd been using PowerPoles and a Rigrunner to distribute 12V to my filter wheel, focuser, etc.  12 V from power supply connected to a Rigrunner via a PowerPole connector, and then PowerPole connectors on through-the-mount cables to the devices.  Pretty straightforward and I'm sure the same as many of you.

Now that I have a remote observatory and am not plugging things in and out all the time, I'm wondering if I should continue to use PowerPoles or use something like a barrier strip with cables screwed into it, or something else.  What are the pro's and con's of the various connectors in an observatory?  It's in the mountains of NM so is pretty dry, gets into the 90's in the summer and teens in the winter.

Eric


Re: Mach2 - Imaging in frigid night

Jim Fakatselis
 

So there is no easy selection for King rate without a model?
Is this perhaps a possible opportunity to add it as an option button in APCC?

Jim


On Jan 23, 2021, at 12:10 PM, Roland Christen via groups.io <chris1011@...> wrote:


Yes, that is correct.

Roland



-----Original Message-----
From: Worsel via groups.io <bryancashion@...>
To: main@ap-gto.groups.io
Sent: Sat, Jan 23, 2021 10:41 am
Subject: Re: [ap-gto] Mach2 - Imaging in frigid night

Roland

Jim's question prompted a related thought.  I assume there is no need even to bother with King rate, if using an APPM model with MGBox for environmental conditions to correct for refraction.  Is this correct?


TIA

Bryan

--
Roland Christen
Astro-Physics


Re: Best way to connect power cables in remote observatory

Barry Megdal
 

I would suggest running whatever devices are sharing the same power (perhaps main and guide camera and focuser (and maybe dew heater depending if the controller you use generates noise) from a RigRunner mounted on top of the scope, and then you only need one power cable up through the scope to the RigRunner.

 

-        Barry

 

Dr. Barry Megdal

 

President

Shb Instruments, Inc.

19215 Parthenia St.  Suite A

Northridge, CA 91324

www.shbinstruments.com

(818) 773-2000  (818)773-2005 fax

bmegdal@...

 

Faculty (retired)

Dept. of Electrical Engineering

Caltech

 


Re: Flexure or tracking? (Another "cold night" from northern Indiana)

Joel Short
 

That's a good idea Ray.  I'll check collimation throughout the sky next time I'm out.
joel


On Sat, Jan 23, 2021 at 12:02 PM Ray Gralak <groups3@...> wrote:
Joel,

> However I now wonder about tilted optics. My collimation tests look good with round stars in the corners across a
> full frame sensor.

You might want to verify that collimation holds throughout the sky by taking short images in different parts of the sky and checking the images for star roundness.

-Ray Gralak
Author of PEMPro
Author of APCC (Astro-Physics Command Center): https://www.astro-physics.com/apcc-pro
Author of Astro-Physics V2 ASCOM Driver: https://www.siriusimaging.com/apdriver


Re: Flexure or tracking? (Another "cold night" from northern Indiana)

Ray Gralak
 

Joel,

However I now wonder about tilted optics. My collimation tests look good with round stars in the corners across a
full frame sensor.
You might want to verify that collimation holds throughout the sky by taking short images in different parts of the sky and checking the images for star roundness.

-Ray Gralak
Author of PEMPro
Author of APCC (Astro-Physics Command Center): https://www.astro-physics.com/apcc-pro
Author of Astro-Physics V2 ASCOM Driver: https://www.siriusimaging.com/apdriver


-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Joel Short
Sent: Saturday, January 23, 2021 9:48 AM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Flexure or tracking? (Another "cold night" from northern Indiana)

Ray,
I use this same focuser (Feathertouch) on another scope with the same camera setup and I don't see this same
effect so I doubt it's focuser sag.
However I now wonder about tilted optics. My collimation tests look good with round stars in the corners across a
full frame sensor. However I have noticed that the diffraction spike on very bright stars has one spike (of 4) that
is much longer than the other 3. If I remember, next time I'm out I'll save an image of this. Any idea if that
indicates a mirror tilt issue? Again, collimation tests look good.

Rolando, I might look around for a replacement low vibration fan for the camera. That's an inexpensive and easy
thing to do so it can't hurt.
joel

On Sat, Jan 23, 2021 at 11:39 AM Ray Gralak <groups3@gralak.com> wrote:


Hi Joel,

> Guiding was quite good. I saw an average RMS RA of 0.4", Dec of 0.3".
> Also, I use an OAG for guiding.

Since auto-guiding looked good, that eliminates mount tracking as the problem. You need to look
elsewhere.

My first thought was tilted/moving optics, a sagging focuser, or a non-orthogonal camera sensor. Or some
mixture of these.

-Ray Gralak
Author of PEMPro
Author of APCC (Astro-Physics Command Center): https://www.astro-physics.com/apcc-pro
Author of Astro-Physics V2 ASCOM Driver: https://www.siriusimaging.com/apdriver


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