Vedic Astrology Excel Chart Builder

I need a single, well-structured Excel workbook that lets me generate astrological charts based strictly on Vedic principles. The flow is simple: I type in birth details (date, time, latitude, longitude, time-zone) and, with one click, the sheet calculates planetary positions, displays an accurate Rashi chart, and produces the full Vimshottari Dasha timeline.

Core functions to build
• Planetary positions: longitudes for Sun through Ketu, automatically adjusted for ayanamsa.
• Rashi (Lagna) chart: clear North or South Indian layout, rendered directly in cells or via a lightweight VBA userform.
• Dasha calculation: full table of Mahadasha, Antardasha, and Pratyantardasha with start-end dates.

I am fine if you rely on native Excel formulas where possible, but feel free to add VBA for astronomical algorithms, ephemeris interpolation, and button-driven refresh. Performance should stay snappy without external add-ins.

Deliverables
1. Unlocked Excel workbook (.xlsx / .xlsm) with the above features fully wired.
2. Brief read-me sheet explaining input fields, calculations, and any macros used.
3. A quick test run showing results for a known horoscope so I can cross-verify accuracy.

Accuracy and clarity take priority over fancy graphics. If you have previously coded planetary algorithms or can cite an ephemeris source you trust, mention it in your proposal so I know the maths is sound.