It is about the solar eclipse that will be happening in the days to come – during the eclipse, usually adiyen will purify and recite Sri Vishnu Sahasranam, chant Ashtakshra mantra japam and after eclipse, perform tharppanam. Have heard that during this period, one can continue to perform the daily Tiruvaradhanam for the Salagrama murthi; is it correct? Is there any special method to perform Tiruvaradhanam during the eclipse? In the Tiruvaradhanam during the eclipse, can we restrict the offering for Perumal to milk, fruit and rock candy (Kalkandu)?

Daily Tiruvaradhanam can be performed for Salagrama murthi during the eclipse.
Yes, there is a special procedure to perform Tiruvaradhanam during an eclipse. Like how during the sankalpam we say ‘ijyaknena’, for the Tiruvaradhanam during the eclipse, we either include ‘somoparaga punya kala aradhana’ or ‘suryoparaga punya kala aradhana’. There are no other differences than these.
Because cooking food is not allowed during an eclipse, for Tiruvaradhanam during the eclipse, only milk, fruit, and rock candy be offered. Particularly, it is a practice to offer fruit and rock candy only.