Sandhavandana normally times normally goes upto 9am in morning and 9pm in evening in India (with prayaschitta arghya). But when outside India, for example in Europe, the sun rise and sun setting times are completely different. Sun comes out at 4am and sets at 9:30pm. Whereas in winter sun comes at 8am and goes down at 4pm. Similarly for Vratas like Sankatahara Chathurthi it says after moon rise but in summer the moon comes after midnight!
Should the local sun rise/sunset timings be observed or can do with prayaschitta? It not possible/practical to wait for sun rise at 8am in winter.