In the period from August 2024 to March 2026, 52 H-alpha observations were carried out using a Sol’Ex spectroheliograph on a TLAPO60/360 and later a TLAPO80/480. Processing via INTI results in superior resolution, meaning the calculated prominence relative number (Rp = 10H + E) is systematically higher than the VdS reference. This is reflected in a k-value of 0.76 with a strong correlation (R2 = 0.88). Furthermore, the data confirm the time-lag effect of the chromosphere: the H-alpha prominence maximum occurs later than the sunspot maximum in the photosphere. This is logically explained by the fact that prominences are often residual phenomena of active regions that are already decaying underneath. The methodology used follows the standard from "Die Sonne beobachten" by Reinsch and Völker.
Determination of the H-alpha Relative Number for the solar limb (Rp or RHa)
The formula is defined as follows (1)
Rp or RHa = 10 H + E
With:
Rp or RHa: the H-alpha relative number
H (Herde): the number of activity centers on the solar limb
E (Einzelerscheinungen): the number of individual limb phenomena, individual phenomena such as separate prominences or limb flares.
(1) Die Sonne beobachten - Reinsch, Beck, Hilbrecht and Volker
Conclusion:
My observations follow those of VdS and Kanzelhohe.
My observations are systematically higher, which may indicate a difference in equipment resolution, cf. traditional H-alpha versus Sol’Ex.
The k-value is 0.76 with a reliability (R2) of 0.88.
Observations confirm the "time-lag" effect of the H-alpha maximum relative to the sunspot number. This is logically consistent, given that sunspots occur in the photosphere and prominences in the chromosphere.
