[vsnet-survey 76] RES: Nova hunting

[Cristovao Jacques Lage de Faria <Cristovao@agnet.com.br>]

Hello W. Liller and T. Kato


>First of all, I wish Cristovao the very, very best of luck.  


>Then used with 35mm film, the 85mm lens provides a field of 15.3 x 23.5
>degrees, and I center my Sagittarius field on Gamma Sgr which sits very
>early at the "center of mass" of the coordinates of galactic nova. 
>Likewise, Lambda Aql is cdentered to get the Scutum Cloud, and 26 Oph to
>pick up some of the novae that seem to frequent that part of the Southern
>Milky Way.

I really apprecciate all the advices coming from Bill. I really thank you as
I'm an admirer of your work.


>One other thought: it's quick and relatively easy to take a dozen or so CCD
>frames; I do it all the time -- but not for nova searching.  The part that
>is time consuming is inspecting the frames.  The process of selecting a
>matching archival frame with similar limiting mag, sky brightness, and star
>shapes, and then aligning the two frames for blinking or subtraction takes
>time.  And finally one has to check out the cosmic ray blemishes,
>asteroids, and known variable stars before spreading the word that you've
>found a nova suspect.

We are on the very beginning of our experience with CCD related to Novae
survey. All that I can tell you, is that we use software that can align and
regulate the sky brightness automaticaly for blinking,so there's no time
consuming issue here.Cosmic rays are a problem, but as the time that  we
acquire the images we can check and re-do them almost imediately. We begun
also a supernovae survey in last september with another scope deticate to
this task, and we use the same principle that we plan to use with the Novae
Survey, although the plate scales are very different.
We acquire and put WCS astrometry information in the header of the fits
files.Plates are solved in real time yielding residuals from 3" to 5" in a
25"/pixel scale. All this is automated. As we go for checking,the WCS
information is used to automatically align the images.We acquire aprox. 500
images of galaxies in a good  night and we spend another 3  to 3 and 1/2
hours analysing them.

This goes to Mr  Kato.

>    Would someone try to use Yoshida-san's PIXY(-2) system to automatically
>check everything on CCD images?  I don't have a firm idea how effective
>PIXY would be for short focal length images, but the software is confirmed
>to be very effective for at least for a longer lens.  The software
>automatically identifies known variables and other catalog objects, so
>the human intervention is minimal.
  
I've already downloaded the PIXY2 system 15 days ago and now I'm learning
how to use it. I'll check it effectiveness for short focal lenght and tell
my results.

>Again, good luck Cristovao.      Bill Liller

I'll really need it.

Regards,

Cristovao Jacques
Wykrota Observatory-CEAMIG
Belo Horizonte - Brazil

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