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Tricolour G magnitudes / utility

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djswan2002's picture
Last seen: 22 hours 28 min ago
Joined: 20/04/2017 - 19:58
Tricolour G magnitudes / utility


Is there anyone out there who occasionally (or routinely) reports tricolour G magnitudes to the VSS? I'd like to hear from you whether the community regards the data as useful.

I have been submitting my observations of HS 0229+8016 via webobs to the AAVSO to see how my TG determinations relate to Johnson V mags reported by others - and they look OK so far.

I've been doing ensemble photometric solutions (Vmags of reference stars), as there are so few APASS gold-standard brightness determinations near to the variable in this case. I am including a check star brightness with each report. I figure 2dp is quite sufficient, as the error does not justify a 3dp precision.


David Swan


Andy Wilson's picture
Last seen: 8 hours 20 min ago
Joined: 29/03/2014 - 16:05
Tricolour G magnitudes

Hi David,

I know a bit about this but I would not call myself an expert.

There are a couple of important points to consider relating to the type of variable star.

First, if all you are interested in is timing, like eclipsing binaries, or detecting the outburst from an object, then a TG filter really should not matter.

When submitting observations to be compared with V filters, if the star has strong emission line features in the spectrum, then I think this can lead to larger differences between a TG and a V filter.

There is an option to submit TG filter observations in the BAA Photometry Database.