As long as you can see your bubble and the celestial body you’re good to go, day or night. I use a professional bubble attachment on my marine sextant to take sights from my back porch. I reduce my sights from a GPS position using a non-programmable trig. calculator as it gives me instant feedback on the accuracy of my sight (intercept should be 0.0 with no plotting required). For a single observation, I can count on my LOP being within 10 NM. If I take the average of 5 sights I can count on a sub 5NM accuracy. This degree of accuracy is usually acceptable in aircraft celestial navigation.