How to plot a transit curve of an exoplanet transit

[Forum_2015]

Do you know how it is easy to make batch photometry with Astroart? See this tutorial (with video) on how to plot an exoplanet transit.

http://www.pixelsoft.it/tut/qatar1b/QATAR1B.html

[Forum_2015]

mnico,

I have used the table of reference stars to measure the variables in my list. I assume I could just collect each star in its own folder each night and then generate the light curve at the end of the month. I will give that a try with the target and Reference star txt file.
But will that file work in batch? It works great for individual variables. Just load the preprocessed image and then select reference.txt and it finds and fills in all the mags of the check and variable star.

[Forum_2015]

Hi,

I have tried to use the same process on a set of variables.
The above process does not seem to use the reference stars to correct the mag of the variable in the plot. It seems to be plotting raw ADUs?
I have calibrated mags for all my reference stars. Why does the plot not have corrected magnitudes?

Regards,
John

[Forum_2015]

Hi John,

if I have correctly understand your question, you should take a series of images of the same field with variable and ref stars, then use the batch photometry tool to collect ALL the images in the "Preprocessing-batch photometry" window and selecting "Align -> Star pattern". It is clear that each image must have the same reference stars as those selected in the first images of the series.

Martino

[Forum_2015]

Hi,

Yes all understood.
but the individual mag calculated normally dont seem to relate to the differential ensemble mags?
my process uses the .txt ref star file to set the ref mags. All are within 0.02 O-C mag. when the text editor lists the ADUs They all match the individual star values done manually, however the Plot does not seem to relate to actual mag or mag error?

regards

John

[Forum_2015]

Files used for test...QQVul darks and a preprocessed Flat.

https://www.dropbox.com/sh/omqhgwn30...xgqqJkPEa?dl=0

The text file is my list of Variable targets and ref stars from AAVSO.

All the best

John

[Forum_2015]

Hi John,

the question of the corrected magnitude is more complex. Astroart can provide you an "instrumental magnitude" that you can correct with a "zero point" setting to calibrate it to a catalog magnitude, but it is still considered an instrumental magnitude because you should calibrate also for colour of the stars and sky extintion to obtain a "real" catalog magnitude in a proper band (B, V or R?)
The task of a software like Astroart is to provide a correct and precise measures of the FLUXES (that's why you read the raw ADUs) and a transformation of these fluxes in instrumental magnitudes.
To obtain a "catalog magnitude" you should use a proper spreadsheet like one of those provided by AAVSO here:
http://www.citizensky.org/content/finishing-analysis

Regards
Martino