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Double Star Measurements

YPFA's picture
YPFA
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Joined: 2012-07-22

Suppose you want to do double star measurements by using "Measure PA / Sep" from the Tools menu ...

Prior to selecting "Measure PA / Sep", if one labels the primary as "Star 1" and the companion as "Star 2", will VPhot automatically centre the concentric circles on the centroid of each star?

If not, how does one do this - getting the circles accurately on top of the centroid would seem to be essential to get good measurements?

Cheers
Paul YPFA

Double Star Measurements
kge's picture
kge
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Joined: 2010-07-19

Hi Paul,

Yes, VPHOT will center on the centroid of the star. It always does when a star is selected (either by clicking on the image or importing from catalogs).

Geir

PA/SEP much different for various telescopes?
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BMAH
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Joined: 2014-02-15

Hello, I'd like to ask more about DS measurements using VPHOT. How much "Telescope setup" affects measurements, if any? Problem is, that my results differ very at a images from different telescopes. 

PA/SEP
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MZK
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Joined: 2010-07-23

Hi Marcin:

A couple of things come to mind, but if you could give a couple of specific examples and/or share images to (MZK), I could look at this? Image scale is necessary but it should be present in Telescope Settings info? If you attach a screen capture to this forum thread it might also help others to comment?

Ken

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BMAH
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Joined: 2014-02-15

This is a screen with the measurements out od iTelescope (T18 - plate scale 0.73) image. Second is a private telescope with a plate scale 1.652. Both images are solved with PinPoint and both show different PA. Both images shared with You. Thanks in advance for help.

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BMAH's picture
BMAH
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Joined: 2014-02-15

Hello, any luck with my images? I'm totally stuck with this problem. I tried also third source - images from different telescope and it is the same situation. Separation show proper result, PA doesn't.

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