A scalar rAgA, going like this :
Aro : S R3 G3 M1 P S
Avaro : S N2 D2 N2 P M1 R3 S
Although PMGMR and SMGM are also possible.
Thyagaraja has a kriti - idi samayamurA inakula tilaka in this rAgA (only known composition, do not confuse with Mysore Vasudevacharya's one in nATakapriya).
Here's MDR, singing it as only he can : https://www.youtube.com/watch?v=WPk4P4sT01M
And here's DKP's version : https://www.youtube.com/watch?v=1dgkKPwsVvM
There used to be a video of Lalgudi Jayaraman playing this for Jaya TV's MMU - but it looks like they've removed it along with the rest of the channel (damn!

Just a while back I had a thread opened on bhOgachAyA nATa and you might wonder what's the difference. They're both very very similar in name and form. And apart from the fact that that this raga is more scalar than Dikshitar's, all the phrases of chAyAnATa are possible in bhOgachAyA nATa, but not vice versa.
Actually they're most likely the same raga itself, just handled differently (just like nATa). Someone may confirm. If I had to evaluate them, I'd say they're the same.