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A tree is growing tall enough to interfere with Three Point Polar Alignment

Acquisition Deep Sky
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AmyWarble avatar
AmyWarble avatar
The first two capture points are still fine, but a tree has grown enough to occlude about 1/3 of the final frame. 

I have tried to google this but I just don't understand what I'm reading and how to apply it.  I've found forum posts saying you can polar align almost anywhere in the sky.   My south sky is completely open, no trees, and is where PHD2 wants to point for calibration, anyway.

I don't know if this matters, but my focal length is 840mm and I'm operating in the northern hemisphere.

I'm feeling a little overwhelmed in trying to solve this myself.  Can someone help me? 


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bigCatAstro avatar
bigCatAstro avatar
AmyWarble:
The first two capture points are still fine, but a tree has grown enough to occlude about 1/3 of the final frame. 

I have tried to google this but I just don't understand what I'm reading and how to apply it.  I've found forum posts saying you can polar align almost anywhere in the sky.   My south sky is completely open, no trees, and is where PHD2 wants to point for calibration, anyway.

I don't know if this matters, but my focal length is 840mm and I'm operating in the northern hemisphere.

I'm feeling a little overwhelmed in trying to solve this myself.  Can someone help me? 



You should be able to select the toggle switch for “Start from current position?” to “on” and that will allow you to run the routine from any star in the part of the sky you’ve pointed to. I do this all the time since Polaris is completely obstructed from my home. I have Stellarium set up to load coordinates to NINA.

i hope this helps!
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AmyWarble avatar
AmyWarble avatar
Really?  That's all I would have to do?

Okay, I will try this.
AmyWarble avatar
AmyWarble avatar
That worked!  I can't believe it was that simple.  I think I can figure out how to automate this.  

Thank you so much, big kitty!
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bigCatAstro avatar
bigCatAstro avatar
AmyWarble:
That worked!  I can't believe it was that simple.  I think I can figure out how to automate this.  

Thank you so much, big kitty!

You’re welcome!  Glad it worked.
Ejo Schrama avatar
Ejo Schrama avatar
AmyWarble:
The first two capture points are still fine, but a tree has grown enough to occlude about 1/3 of the final frame. 

I have tried to google this but I just don't understand what I'm reading and how to apply it.  I've found forum posts saying you can polar align almost anywhere in the sky.   My south sky is completely open, no trees, and is where PHD2 wants to point for calibration, anyway.

I don't know if this matters, but my focal length is 840mm and I'm operating in the northern hemisphere.

I'm feeling a little overwhelmed in trying to solve this myself.  Can someone help me? 



You should be able to select the toggle switch for “Start from current position?” to “on” and that will allow you to run the routine from any star in the part of the sky you’ve pointed to. I do this all the time since Polaris is completely obstructed from my home. I have Stellarium set up to load coordinates to NINA.

i hope this helps!

The solution is to start from the current position and to stop asking your housemates, spouse, etc whether that tree could be trimmed.
AmyWarble avatar
AmyWarble avatar
@Ejo Schrama I don't know why you would suggest that I need to "stop asking your housemates, spouse, etc whether that tree could be trimmed."  That comment seems wholly unnecessary when I made no suggestion that trimming the tree was ever being considered.
Phil Bordelon avatar
Phil Bordelon avatar
In one of my imaging locations on my very small patio, I have a view of the sky that is clear horizon-to-horizon east to west, but the north-south view is only about 45° wide directly overhead.  I have better views elsewhere, but it's the only place I can leave my rig unattended all night long.

In order to complete TPPA in that predicament, I simply toggle Manual Mode on and slew to an initial sky location.  In manual mode, NINA solves the first image, then continues imaging while I manually slew to the 2nd location, wait for that solve, then go to the 3rd location to complete TPPA.  The 2nd and 3rd locations need to be at least 10° apart.



TPPA might work my restricted view in  "Start from current position" mode, but I'm not absolutely sure, NINA's choice for points 2 and 3 would be within my very restricted sky view.