HOA Activity; Observing Delta Cephei

From most latitudes in the northern hemisphere in the autumn, delta Cephei is bright and high in the sky - away from the horizon and local light pollution. It is outside the Milky Way and in a fairly dark and uncluttered region of the sky.

1. Enter in your logbook the name of the star (delta Cephei), the date of the observing session, and the hour (later you will enter the minutes to the nearest quarter hour).
2. Using your planisphere or star charts, find the Big Dipper and Polaris using the pointer stars.
3. "Star hop" to Cassiopeia and then to Cepheus (see above).
4. Find the group of three stars near one corner of the rectangular portion of Cepheus. Here is delta Cephei and its comparison stars, zeta Cephei (magnitude 3.6) and epsilon Cephei (magnitude 4.2). This is the most difficult part and may take you several attempts, as you alternately look at the chart (above) and the sky.
5. Using averted vision, observe the variable star and its comparison stars at the center of your field of view. Averted vision is a technique in which you orient the star at the center of your field of view, and then gaze at the edge of the field. Peripheral vision is more sensitive to black and white, so the difference in magnitude will be easier to discern.
6. Estimate your variable star's magnitude to the nearest tenth by using the nearby comparison stars. Look quickly back and forth and ask yourself: Is it dimmer or brighter than this comparison star? Is it dimmer or brighter than the second comparison star? If it is brighter, by how many tenths? Make a note of it. Then estimate the magnitude of your variable star again, and do it a third time. Enter the three numbers and average them in your logbook; then record your result in the data table.
7. Record the names and magnitudes of the comparison stars used.
8. Record the time of your observation to the nearest quarter hour.
9. Place a colon [:] after your observation if you are unsure of your observations due to a bright Moon or possible cirrus clouds. Do not be discouraged if you initially cannot tell the difference between a star of 3.0 and 3.5 in magnitude. Remember, your observations are a valuable "part of the whole" even if you are not yet an expert observer. With experience, you will be able to make your observations much more accurately and quickly.