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About Tranformations, VPHOT and Landolf comp stars

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astrolopitec's picture
About Tranformations, VPHOT and Landolf comp stars


I'm beginning to tackle the subject of Transformations so this weekend I took some nice VBR series of M67.

I uploaded one of the images into VPHOT and was surprised that it only found one comp star in the entire field. Even funnier it found 31 variables!

What gives? Am I doing something wrong?



astrolopitec's picture
So are all these stars in M67

So are all these stars in M67 really variables? Only one comp?

Makes no sense to me. But then again that's nothing new.



TCB168's picture
Landolt fields

It just means that the so called standard stars in the M67 field have not been entered into the database. The variables will be real at least at the level of "suspected" variable.

If you try an actual Landolt field rather than M67, the stars will be there.

Some time ago I formatted the data and they have been entered.

A page of the fields is here



Terry B

astrolopitec's picture
Thank you very much Terry.

Thank you very much Terry. That was most informative. In fact your link should be included in the CCD Resource and Reading List page

I would also like to thank you for your work entering all the data for the "official" Landolf fields.  

Juan Herrero

FJQ's picture
Landolt Standard Fields


Here 's a link we used for night to night all-sky photometric reduction from landolt fields:

James - FJQ

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