Which is more realiable: NED or SIMBAD?

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NED and SIMBAD provide differing luminosity values for M33, with NED listing 6.27 and SIMBAD 5.27, raising questions about reliability. The discrepancy of exactly 1 prompted a comparison of both databases for Z or luminosity values. It was clarified that both databases agree on the B band magnitude, but the reliability of luminosity values remains uncertain. The integration methods for measuring brightness over extended objects like M33 may vary between databases, contributing to the differences. Ultimately, the choice between NED and SIMBAD may depend on specific research needs and the context of the data used.
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I'm doing some research on M33. NED lists the luminosity as 6.27. SIMBAD gives it as 5.27. First, it looks odd to me that the difference is exactly 1. Second, I've seen other differences comparing identical extragalactic bodies, so which database is more reliable?

Note: it appears I misread the band data. NED and SIMBAD show the same value for the B band magnitude. However, the question still remains: is there a preference between the two for Z or luminosity values?
 
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Depends. How do they integrate the brightness over the surface of an extended object, like M33? There are probably as many answers as there are databases.
 
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