Tips for creating new PE curve?


Jeffc
 

I’m finally getting around to upgrading an AP1200 CP3 to the V2 chip. I’m pretty sure there is a pre Q version in there now. So, it is going to need a new PE curve.

I’ll use PemPro of course.

I’m probably over-thinking this but …
Are there any tips for getting a good curve?
Eg given seeing conditions and camera/OTA options?
(For example, a 12” ACF SCT is normally used with this mount, and I don’t think the SCT would be a good OTA for recording a PE curve. I’m thinking of enlisting one of the refractors for this task and keep the setup as simple as possible.)

I’m guessing the OTA camera combo doesn’t matter much as long as the image scale is appropriate.

That said , can I use a short focal length OTA / small pixels resulting in undersampled stars? (Eg I presume PemPro does sub pixel calculations for determine PE.)

The easiest / most convenient thing I could do is use the AP92 stowaway with the BARDAV (2x barlow) and the ST-I mono. This would be 1.26 arcsec/pixel.
(I would need to manually focus tho as the focus motor is not on the AP92).

How important is a flat field?
I would think this is fine if a star near the center of the FOV is used.

What about flexure? I’m thinking a physically short OTA would be better tho I have some options (eg AP92 vs 130GT.)

I presume any Tilt wouldn’t be an issue if I focus on the center of the FOV. Correct?

Orthogonality? I thought orthogonality was only critical for gotos.
I could do some shimming if i really really need to.

I could go with smaller pixels if it helps. Specifically the QHY268M. But then there’s more bulk. (Sure it can handle it. It’s also a hassle borrowing the 268 from the another setup.)
In this case I might consider using the 268 with a 130GT resulting in 0.95 arcsec/pixel.

Thx for any suggestions.

-jeff


Roland Christen
 

See below in red:
That said , can I use a short focal length OTA / small pixels resulting in undersampled stars?  (Eg I presume PemPro does sub pixel calculations for determine PE.)

Certainly you can use a short focal length such as the 92 Stowaway. Will work perfectly.

How important is a flat field? 
I would think this is fine if a star near the center of the FOV is used.

Flat field is not important at all.

What about flexure?  I’m thinking a physically short OTA would be better tho I have some options (eg AP92 vs 130GT.)

Flexure would not really be a factor when using either refractor.

I presume any Tilt wouldn’t be an issue if I focus on the center of the FOV.  Correct?

Tilt is not an issue regardless of which star the program uses.

Orthogonality?    I thought orthogonality was only critical for gotos. 
I could do some shimming if i really really need to. 

Orthogonality does not come into play.
Rolando

-----Original Message-----
From: Jeffc <jeffcrilly@...>
To: main@ap-gto.groups.io
Sent: Sat, Feb 12, 2022 1:58 pm
Subject: [ap-gto] Tips for creating new PE curve?


I’m finally getting around to upgrading an AP1200 CP3 to the V2 chip.  I’m pretty sure there is a pre Q version in there now.  So, it is going to need a new PE curve. 

I’ll use PemPro of course. 

I’m probably over-thinking this but …
Are there any tips for getting a good curve? 
Eg given seeing conditions and camera/OTA options?
(For example, a 12” ACF SCT is normally used with this mount, and I don’t think the SCT would be a good OTA for recording a PE curve.  I’m thinking of enlisting one of the refractors for this task and keep the setup as simple as possible.)

I’m guessing the OTA camera combo doesn’t matter much as long as the image scale is appropriate. 

That said , can I use a short focal length OTA / small pixels resulting in undersampled stars?  (Eg I presume PemPro does sub pixel calculations for determine PE.)

The easiest / most convenient thing I could do is use the AP92 stowaway with the BARDAV (2x barlow) and the ST-I mono.  This would be 1.26 arcsec/pixel. 
(I would need to manually focus tho as the focus motor is not on the AP92).

How important is a flat field? 
I would think this is fine if a star near the center of the FOV is used.

What about flexure?  I’m thinking a physically short OTA would be better tho I have some options (eg AP92 vs 130GT.)

I presume any Tilt wouldn’t be an issue if I focus on the center of the FOV.  Correct?

Orthogonality?    I thought orthogonality was only critical for gotos. 
I could do some shimming if i really really need to. 

I could go with smaller pixels if it helps.  Specifically the QHY268M.  But then there’s more bulk.  (Sure it can handle it.  It’s also a hassle borrowing the 268 from the another setup.)
In this case I might consider using the 268 with a 130GT resulting in 0.95 arcsec/pixel. 

Thx for any suggestions.

-jeff







--
Roland Christen
Astro-Physics


Jeffc
 

Thx very much for the quick confirmation!

-jeff


On Sat, Feb 12, 2022 at 12:16 PM Roland Christen via groups.io <chris1011=aol.com@groups.io> wrote:
See below in red:
That said , can I use a short focal length OTA / small pixels resulting in undersampled stars?  (Eg I presume PemPro does sub pixel calculations for determine PE.)

Certainly you can use a short focal length such as the 92 Stowaway. Will work perfectly.

How important is a flat field? 
I would think this is fine if a star near the center of the FOV is used.

Flat field is not important at all.

What about flexure?  I’m thinking a physically short OTA would be better tho I have some options (eg AP92 vs 130GT.)

Flexure would not really be a factor when using either refractor.

I presume any Tilt wouldn’t be an issue if I focus on the center of the FOV.  Correct?

Tilt is not an issue regardless of which star the program uses.

Orthogonality?    I thought orthogonality was only critical for gotos. 
I could do some shimming if i really really need to. 

Orthogonality does not come into play.
Rolando

-----Original Message-----
From: Jeffc <jeffcrilly@...>
To: main@ap-gto.groups.io
Sent: Sat, Feb 12, 2022 1:58 pm
Subject: [ap-gto] Tips for creating new PE curve?


I’m finally getting around to upgrading an AP1200 CP3 to the V2 chip.  I’m pretty sure there is a pre Q version in there now.  So, it is going to need a new PE curve. 

I’ll use PemPro of course. 

I’m probably over-thinking this but …
Are there any tips for getting a good curve? 
Eg given seeing conditions and camera/OTA options?
(For example, a 12” ACF SCT is normally used with this mount, and I don’t think the SCT would be a good OTA for recording a PE curve.  I’m thinking of enlisting one of the refractors for this task and keep the setup as simple as possible.)

I’m guessing the OTA camera combo doesn’t matter much as long as the image scale is appropriate. 

That said , can I use a short focal length OTA / small pixels resulting in undersampled stars?  (Eg I presume PemPro does sub pixel calculations for determine PE.)

The easiest / most convenient thing I could do is use the AP92 stowaway with the BARDAV (2x barlow) and the ST-I mono.  This would be 1.26 arcsec/pixel. 
(I would need to manually focus tho as the focus motor is not on the AP92).

How important is a flat field? 
I would think this is fine if a star near the center of the FOV is used.

What about flexure?  I’m thinking a physically short OTA would be better tho I have some options (eg AP92 vs 130GT.)

I presume any Tilt wouldn’t be an issue if I focus on the center of the FOV.  Correct?

Orthogonality?    I thought orthogonality was only critical for gotos. 
I could do some shimming if i really really need to. 

I could go with smaller pixels if it helps.  Specifically the QHY268M.  But then there’s more bulk.  (Sure it can handle it.  It’s also a hassle borrowing the 268 from the another setup.)
In this case I might consider using the 268 with a 130GT resulting in 0.95 arcsec/pixel. 

Thx for any suggestions.

-jeff







--
Roland Christen
Astro-Physics


Jeffc
 

It seems to be working....  here's a pempro run after loading the new curve.... 


PE-with-PEC-on-after-programming.jpg


On Sat, Feb 12, 2022 at 12:45 PM Jeffc via groups.io <jeffcrilly=gmail.com@groups.io> wrote:
Thx very much for the quick confirmation!

-jeff


On Sat, Feb 12, 2022 at 12:16 PM Roland Christen via groups.io <chris1011=aol.com@groups.io> wrote:
See below in red:
That said , can I use a short focal length OTA / small pixels resulting in undersampled stars?  (Eg I presume PemPro does sub pixel calculations for determine PE.)

Certainly you can use a short focal length such as the 92 Stowaway. Will work perfectly.

How important is a flat field? 
I would think this is fine if a star near the center of the FOV is used.

Flat field is not important at all.

What about flexure?  I’m thinking a physically short OTA would be better tho I have some options (eg AP92 vs 130GT.)

Flexure would not really be a factor when using either refractor.

I presume any Tilt wouldn’t be an issue if I focus on the center of the FOV.  Correct?

Tilt is not an issue regardless of which star the program uses.

Orthogonality?    I thought orthogonality was only critical for gotos. 
I could do some shimming if i really really need to. 

Orthogonality does not come into play.
Rolando

-----Original Message-----
From: Jeffc <jeffcrilly@...>
To: main@ap-gto.groups.io
Sent: Sat, Feb 12, 2022 1:58 pm
Subject: [ap-gto] Tips for creating new PE curve?


I’m finally getting around to upgrading an AP1200 CP3 to the V2 chip.  I’m pretty sure there is a pre Q version in there now.  So, it is going to need a new PE curve. 

I’ll use PemPro of course. 

I’m probably over-thinking this but …
Are there any tips for getting a good curve? 
Eg given seeing conditions and camera/OTA options?
(For example, a 12” ACF SCT is normally used with this mount, and I don’t think the SCT would be a good OTA for recording a PE curve.  I’m thinking of enlisting one of the refractors for this task and keep the setup as simple as possible.)

I’m guessing the OTA camera combo doesn’t matter much as long as the image scale is appropriate. 

That said , can I use a short focal length OTA / small pixels resulting in undersampled stars?  (Eg I presume PemPro does sub pixel calculations for determine PE.)

The easiest / most convenient thing I could do is use the AP92 stowaway with the BARDAV (2x barlow) and the ST-I mono.  This would be 1.26 arcsec/pixel. 
(I would need to manually focus tho as the focus motor is not on the AP92).

How important is a flat field? 
I would think this is fine if a star near the center of the FOV is used.

What about flexure?  I’m thinking a physically short OTA would be better tho I have some options (eg AP92 vs 130GT.)

I presume any Tilt wouldn’t be an issue if I focus on the center of the FOV.  Correct?

Orthogonality?    I thought orthogonality was only critical for gotos. 
I could do some shimming if i really really need to. 

I could go with smaller pixels if it helps.  Specifically the QHY268M.  But then there’s more bulk.  (Sure it can handle it.  It’s also a hassle borrowing the 268 from the another setup.)
In this case I might consider using the 268 with a 130GT resulting in 0.95 arcsec/pixel. 

Thx for any suggestions.

-jeff







--
Roland Christen
Astro-Physics