YENRA — COMET PLANNING AND OBSERVING LOG
Guide: https://yenra.com/comets/
Version: September 10, 2026

Open this file in a text editor. Save a separate copy for each session.
Keep the original ephemeris output and its header beside your saved log.
Blank entries mean unknown, not zero. Predictions are not observations.
This log is for night-sky observing. Never sweep near the Sun with optics.
Safety context: https://science.nasa.gov/eclipses/safety/

1. IDENTIFY THE SESSION
Comet's full designation:
Observer/site:
Latitude and longitude (degrees; state N/S and E/W):
Elevation above sea level (meters, if entered):
Local date and intended time range:
UTC date and time range:
Local UTC offset (including daylight-saving time, if applicable):

2. PRESERVE THE PREDICTION
Ephemeris provider: https://ssd.jpl.nasa.gov/horizons/app.html
Settings reference: https://ssd.jpl.nasa.gov/horizons/manual.html
Target selected / solution identification:
Observer location selected:
Output time scale and sampling interval:
Date/time the ephemeris was generated:
Saved output filename:
Predicted azimuth (degrees clockwise from north):
Predicted elevation/altitude (degrees above horizon):
Solar elongation (degrees; distinct from altitude):
Predicted total magnitude and exact field label:
Moon phase and altitude / source:
Twilight and Sun status:
Local obstruction in that direction:
Forecast clouds, haze and source:

3. OBSERVE
Actual start/end times (state time scale):
Equipment, aperture and magnification if applicable:
Sky transparency / light pollution / seeing:
Chart and identifiable reference stars:
Directly observed position and appearance:
Coma, central condensation and tail description:
Detection, uncertain candidate, or unsuccessful search:
Sketch or photograph filename:
Photo exposure/processing details if relevant:

4. CHECK AND LEARN
Did the clock, location and field orientation agree with the chart?
Was the target above the actual obstructed horizon?
Follow-up position and time, if used to confirm motion:
Possible reason for an unsuccessful search:
One change for the next session:

DECISION EXAMPLE — INVENTED, NOT A FORECAST
A: magnitude 5.0, altitude 8 degrees, bright twilight.
B: magnitude 5.5, altitude 25 degrees, darker sky, Moon down.
B is more promising despite being fainter in total magnitude.
Visibility still depends on coma size, sky conditions and equipment.