Final answer:
Rukmani uses visual images related to stars, the moon, and the contrast between dark and light to describe her memories of the night Nathan died, emphasizing the beauty of the celestial and its interplay with the landscape during the transition into night.
Step-by-step explanation:
In the passages provided, the visual images Rukmani uses to describe her memories of the night Nathan died are predominantly related to stars, the moon, and transitions from darkness to light. She vividly portrays the night, utilizing metaphors and descriptive language that invoke the beauty of the celestial and its interplay with the landscape.
The excerpts mention a 'golden-red haze of the afterglow of sunset', the 'shades of twilight', and the 'searching gaze she had kept steadfastly upon the purple slope', with the valley deepening into twilight and awash in the glow of a rising moon.