Rahu kalam, Yamaganda and Gulika
Rahu kalam is one of the eight equal parts of the daytime from sunrise to sunset: the 8th on Sunday, the 2nd on Monday, the 7th on Tuesday, the 5th on Wednesday, the 6th on Thursday, the 4th on Friday and the 3rd on Saturday; so it moves with the place's own sunrise and sunset.
The windows of the day the panchang names.
| Weekday | Rahu kalam (part of 8) |
|---|---|
| Ravivara (Sunday) | 8th |
| Somavara (Monday) | 2nd |
| Mangalavara (Tuesday) | 7th |
| Budhavara (Wednesday) | 5th |
| Guruvara (Thursday) | 6th |
| Shukravara (Friday) | 4th |
| Shanivara (Saturday) | 3rd |
Rahu kalam is a South Indian almanac table: no verse was found for it, so the app labels it a regional convention. Yamaganda and Gulika are the eighths ruled by Guru and Shani, counting the day's eight parts from the weekday's lord in weekday order, the eighth part lordless (Brihat Parashara Hora Shastra ch. 3; Kalaprakasika chs. 33-34). Checked against BOB-Nakshatra at three places on ten days, within two minutes.