Create a PEM curve with a camera?


David Enck
 

Hello All, This may be a silly question, but can I use an ASI 290 mini guide camera (2.9 pixel size) through my guide scope (162 mm focal length) to create a PEM curve for my AP1100  when the day comes? Or should  it be through the   main scope.  It is a  Meade lx850 14 inch SCT..  Thinking the guide scope would avoid any mirror shift and such.. My main imaging  camera is a Canon T2i.. 

Thank you,  David


Stuart <stuart.j.heggie@...>
 

Hey David, I'm sure you're right to be wondering about the guide scope approach. Have you used this guide scope / main scope together before and confirmed there is no flexure? If you haven't I'd be worried that you'll build a PEC curve for the guide scope only. 


On Wed, 20 May 2020 at 20:06, <davidenck@...> wrote:
Hello All, This may be a silly question, but can I use an ASI 290 mini guide camera (2.9 pixel size) through my guide scope (162 mm focal length) to create a PEM curve for my AP1100  when the day comes? Or should  it be through the   main scope.  It is a  Meade lx850 14 inch SCT..  Thinking the guide scope would avoid any mirror shift and such.. My main imaging  camera is a Canon T2i.. 

Thank you,  David


--

Stuart
http://www.astrofoto.ca/stuartheggie/


Roland Christen
 

I think so if you have a good pixel scale.

Rolando



-----Original Message-----
To: main@ap-gto.groups.io
Sent: Wed, May 20, 2020 7:06 pm
Subject: [ap-gto] Create a PEM curve with a camera?

Hello All, This may be a silly question, but can I use an ASI 290 mini guide camera (2.9 pixel size) through my guide scope (162 mm focal length) to create a PEM curve for my AP1100  when the day comes? Or should  it be through the   main scope.  It is a  Meade lx850 14 inch SCT..  Thinking the guide scope would avoid any mirror shift and such.. My main imaging  camera is a Canon T2i.. 

Thank you,  David


Bill Long
 

Should work fine, IIRC Ray has a special version of PHD just for PEMPro usage.


From: main@ap-gto.groups.io <main@ap-gto.groups.io> on behalf of Stuart <stuart.j.heggie@...>
Sent: Wednesday, May 20, 2020 5:08 PM
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Subject: Re: [ap-gto] Create a PEM curve with a camera?
 
Hey David, I'm sure you're right to be wondering about the guide scope approach. Have you used this guide scope / main scope together before and confirmed there is no flexure? If you haven't I'd be worried that you'll build a PEC curve for the guide scope only. 


On Wed, 20 May 2020 at 20:06, <davidenck@...> wrote:
Hello All, This may be a silly question, but can I use an ASI 290 mini guide camera (2.9 pixel size) through my guide scope (162 mm focal length) to create a PEM curve for my AP1100  when the day comes? Or should  it be through the   main scope.  It is a  Meade lx850 14 inch SCT..  Thinking the guide scope would avoid any mirror shift and such.. My main imaging  camera is a Canon T2i.. 

Thank you,  David


--

Stuart
http://www.astrofoto.ca/stuartheggie/


Roland Christen
 

The PE curve will apply to the mount, and has no bearing on what happens to the main scope flexure. By definition the PE curve cannot store flexure and making a PE curve automatically throws out any flexure component because it is not periodic.

Rolando


-----Original Message-----
From: Stuart <stuart.j.heggie@...>
To: main@ap-gto.groups.io
Sent: Wed, May 20, 2020 7:08 pm
Subject: Re: [ap-gto] Create a PEM curve with a camera?

Hey David, I'm sure you're right to be wondering about the guide scope approach. Have you used this guide scope / main scope together before and confirmed there is no flexure? If you haven't I'd be worried that you'll build a PEC curve for the guide scope only. 


On Wed, 20 May 2020 at 20:06, <davidenck@...> wrote:
Hello All, This may be a silly question, but can I use an ASI 290 mini guide camera (2.9 pixel size) through my guide scope (162 mm focal length) to create a PEM curve for my AP1100  when the day comes? Or should  it be through the   main scope.  It is a  Meade lx850 14 inch SCT..  Thinking the guide scope would avoid any mirror shift and such.. My main imaging  camera is a Canon T2i.. 

Thank you,  David

--

Stuart
http://www.astrofoto.ca/stuartheggie/


David Enck
 

Ok, great!  Thanks all for the information.  

David 

On May 20, 2020, at 5:18 PM, uncarollo2 <chris1011@...> via groups.io <chris1011@...> wrote:


The PE curve will apply to the mount, and has no bearing on what happens to the main scope flexure. By definition the PE curve cannot store flexure and making a PE curve automatically throws out any flexure component because it is not periodic.

Rolando


-----Original Message-----
From: Stuart <stuart.j.heggie@...>
To: main@ap-gto.groups.io
Sent: Wed, May 20, 2020 7:08 pm
Subject: Re: [ap-gto] Create a PEM curve with a camera?

Hey David, I'm sure you're right to be wondering about the guide scope approach. Have you used this guide scope / main scope together before and confirmed there is no flexure? If you haven't I'd be worried that you'll build a PEC curve for the guide scope only. 


On Wed, 20 May 2020 at 20:06, <davidenck@...> wrote:
Hello All, This may be a silly question, but can I use an ASI 290 mini guide camera (2.9 pixel size) through my guide scope (162 mm focal length) to create a PEM curve for my AP1100  when the day comes? Or should  it be through the   main scope.  It is a  Meade lx850 14 inch SCT..  Thinking the guide scope would avoid any mirror shift and such.. My main imaging  camera is a Canon T2i.. 

Thank you,  David

--

Stuart
http://www.astrofoto.ca/stuartheggie/


 

Generally people build PEC using their main scope, provided it's 0.5"/pix or less resolution. 



On Wed, May 20, 2020 at 6:29 PM David Enck <davidenck@...> wrote:
Ok, great!  Thanks all for the information.  

David 

On May 20, 2020, at 5:18 PM, uncarollo2 <chris1011@...> via groups.io <chris1011=aol.com@groups.io> wrote:


The PE curve will apply to the mount, and has no bearing on what happens to the main scope flexure. By definition the PE curve cannot store flexure and making a PE curve automatically throws out any flexure component because it is not periodic.

Rolando


-----Original Message-----
From: Stuart <stuart.j.heggie@...>
To: main@ap-gto.groups.io
Sent: Wed, May 20, 2020 7:08 pm
Subject: Re: [ap-gto] Create a PEM curve with a camera?

Hey David, I'm sure you're right to be wondering about the guide scope approach. Have you used this guide scope / main scope together before and confirmed there is no flexure? If you haven't I'd be worried that you'll build a PEC curve for the guide scope only. 


On Wed, 20 May 2020 at 20:06, <davidenck@...> wrote:
Hello All, This may be a silly question, but can I use an ASI 290 mini guide camera (2.9 pixel size) through my guide scope (162 mm focal length) to create a PEM curve for my AP1100  when the day comes? Or should  it be through the   main scope.  It is a  Meade lx850 14 inch SCT..  Thinking the guide scope would avoid any mirror shift and such.. My main imaging  camera is a Canon T2i.. 

Thank you,  David

--

Stuart
http://www.astrofoto.ca/stuartheggie/



--
Brian 



Brian Valente


Tom Blahovici
 

Hi . Does this mean that if I use an stl11000 that gives 3.6" that I should not bother?
Tom