The center plate

[Patrick]

Hello,
In script functions, for example Image.EstimateRaDec what is defined as "the center plate"?
Regards,
Patrick.

[AlessandroMaitan]

Hi Patrick,
"center plate" is a geometrical definition of the coordinates (x/2,y/2) where x and y are the numbers of the pixels of the sensor.
Regards.

Alessandro Maitan

[Patrick]

Alessandro,
Thank you. Very clear.
Regards,
Patrick.

[Patrick]

Hello again,
Further to the response above,Is the central plate the center of the sensor, or perhaps could it be also the center of an image or a rectangle?

What is the function of the Center plate selectors in the Astrometry window?
Regards,
Patrick.

[AlessandroMaitan]

Hello Patrick,
the answer to the first question is yes, it could be also the center of an image. According to my understanding the always a geometrical definition (i.e. an image, either cropped or not, is centered at coordinates x and y).
The center plate selection is not in the Astrometry window but you can always select it with View -> Grid.
I hope to have understood your question.

Regards

Alessandro

[Patrick]

Alessandro
Thanks for the answer to the first question.
The Center plate details I referred to is seen if i follow the Tutorial on Plate Solving (AA8 SP4 User's Guide p. 16) then select Astrometry from the Tools menu.

Patrick.

[AlessandroMaitan]

Hello Patrick,
in the Astrometry panel of the Tool Menu the item "Center Plate", as far as I have understood, indicates the precision in pixel (0.5 is the suggested precision) of the position of the center plate once the Astrometry calculation have been done. It is indicated by a red inclined cross in the image you are analysing.

Regards

Alessandro

[Patrick]

Alessandro,
Thanks for the response.
This all seems outside my level and is best left alone by me.
Regards,
Patrick