Hi, so I hope you all don’t mind the new topics, but as I read more and more the more questions I think of 
. My setup is a 750mm Newtonian telescope and the camera I’ll be using is the ASI 6200 Color camera. All of the manuals I see on the AAVSO site always mention and specify using monocrhome…First of all why is monochrome preferred? and Can color images still be used to produce light charts?
I also have Pixinsight and photoshop so does anything need to be done extra to the color images ?
Here is a link to the AAVSO DSLR photometry guide. This is the publication relevent to colour cameras.
Hi. I have been recently using a ZWO ASIAir 585 Duo colour camera and have gotten some decent results.The light curves below, (the star YZ CMi), were captured with a 130mm Newtonian at 200 gain with 30s exposures and were calibrated with flats and darks. The colour images were split into the three channels by Vphot, then analyzed. The upper Red curve is transformed into standard magnitudes whereas the lower curves are the transformed data for the V and B bands. The differences emphasize the need for the data to be transformed to standard magnitude, although the V band is a small transformation. For certain types of observations transforming the data may not be crucial (timing eclipsing binaries for example).
So photometry can certainly be done with a colour camera, but I also use a mono setup which would be my main unit.
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Thanks so much! Is “Standard magnitude” a specific value?
Thanks for the response, I did see this, but Does it matter though that I’m not really using a DSLR? it’s a dedicated CMOS astro camera
The same principles apply to photometry with a dedicated astro camera as those that apply to photometry with a DSLR camera.
Standard magnitude is the magnitude of an object within a standard photometric system, such as Johnson-Cousins. Contrast this with instrumental magnitude, calculated as
-2.5 x log(a)
Where “a” represents the raw counts of star minus background sky. Note the minus sign.
Instrumental magnitude is converted to standard magnitude by the formula
Vvar = Vcomp + vvar - vcomp
Where
Vvar is the calculated standard Johnson V magnitude of the variable star
Vcomp is the catalogue standard Johnson V magnitude of the comparison star
vvar and vcomp are the instrumental magnitudes of the variable and comparison stars respectively.
Clarification: we usually refer just to “Johnson V magnitude” not “standard Johnson V magnitude”.
Further clarification: standard magnitude also signifies that the measurement is a “true” magnitude in contrast to differential magnitude, calaculated as
vvar - vcomp
It is not recommended that differential magnitudes be submitted to the AAVSO International Database. However, they are useful if, for example, you want to do a quick check on the precision of your measurements or a quick check on the shape of a light curve from time series photometry taken over a few hours.