[vsnet-chat 5906] Re: (fwd) Re: ResSkySurvey and PIXY

["Sebastian Otero" <varsao@fullzero.com.ar>]

Dear all,

> As I said Sebastian check a big amount file from night
> 8/9 January and reejected some variables. Strange he
> observed that errors linear changing from -0.3 mag at
> 5 mag to 0 mag at 7.3-7.8 mag and >+0.4 at >9 mag, Maybe
> we can apply some corrections to to my Survey values ;)
> But Sebastian must write about this conclusions itself.

Yes, it was surprising to find a relation between V magnitude measured and
actual V magnitude of the star.
And also interesting that there is no color-dependence in this relation.
I won't try to explain it (maybe some of you can do it), but only show the
numbers:

This relation can be at first look be expressed by this table:

(Vm= V mag. measured)

Vm                        Vm-V

Brighter than 4.8    -0.25

4.8 - 6.0               -0.2

6.0 - 6.8               -0.15

6.8 - 7.2               -0.1

7.2 - 7.5               -0.05

7.5 - 7.8                 0

7.8 - 8.0               +0.05

8.0 - 8.2              +0.1

8.2 - 8.3              +0.15

8.3  - 8.4             +0.2

8.4 - 8.5              +0.25

8.5 - 8.65            +0.3

8.65 - 8.8            +0.35

8.8 - 9.0              +0.4

<9.0                     >+0.45

Beyond 9.0 it all gets very noisy and useless.

Corrections and wrong ID's have been sent to Maciej for his use.

I think it would be a ggod idea to make a filtering by magnitude. It would
help the identification and solve most of the wrong ID's to put a limitting
magnitude to the survey.
For instance if no star fainter than 9.0 mag. is included , there wouldn't
be dozens of stars of mag. 14, 15, 16. misidetified with 5th or 6th mag.
stars nearby....;-((
The Orion Nebula and its faint flare stars is a annyong example on "how to
kill visual observers@!"

Cheers,
Sebastian.




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