THE ROYAL ASTRONOMICAL SOCIETY OF CANADA

STANDING COMMITTEE ON OBSERVATIONAL ACTIVITIES


                                    AURORA SECTION                      Bulletin No. 4


To obtain more information from our aurora observers and to establish an R.A.S.C. auroral
data file, this bulletin describes two stumnary forms. These can easily be duplicated
by Centres or individual observers and are intended as a supplenent to, not a replacement
for, the present N.R.C. aurora report form.

MONTHLY AURORA SUMMARY: At the top, the name of the observer, month and year, station
or location where the observations have been made, and the time used during the entire
month should be given. Below this, a list of standard symbols is found for use singly
or in combination.

In the main section, observational data should be entered - across the page ar columns
for the various hours of each night, down the page are tars for the days of the month.
For each hour of the night when an observation has been made, an appropriate symbol
should be entered along the daily rows.

Four examples are shown:

  - On July 5-6 the sky was clear between 22h and 02h. Twilight interfered with ob-
    servation until 23h, after that no aurora was seen during three consecutive hours
    of observing.

  - On July 10-U the sky was overcast between 22h and OOh. Between 00h and 01h the
    sky partially cleared but the northern sky was still clouded over. During the
    next hour the sky was partially cloudy aU over, and by 02h the sky had again be-
    came overcast.

  - On July 22-23 a weak aurora was observed prior to 23h and again after 00h. No
    observation was made between 23h and 00h.

  - On July 23-24 the sky was partially cloudy between 21h and 02h. The north was
    clear during most of this interval but no aurora was seen before 22h the to twi-
    light. After 22h no aurora wag observed in the north until 01h when a medium
    aurora was noted, After 02h the sky cleared and the medium aurora continued.


DAILY AURORA SUMMARY:  This is used only when an aurora has been seen and recorded on
the N.R.C. Visual Aurora Report form; the display is then summarized on the daily
summary form for use by an R.A.S.C. Centre Recorder or the National Co-ordinator.

At the top are spaces where the observer's name, location or station, and the time used
for the observations should be entered. A short list of preferred symbols for the
auroral forms and their intensities follows.

The main portion is for the summary of the observations. Elevations indicating the
position of the aurora relative to the northern horizon appear across the top. Angles
larger than 90° are south of the zenith, 180° is the southern horizon. Times of

Aurora Section, Bulletin No.14.                                                  -2-


observations should be entered in the left-hand column; four per hour should suffice.
Observations need not be made at the quarter hours, but these are preferred for ease
of cauparison among observers. The right-hand column is for remarks on colour,
motion, time of greatest activity and time of transition between forms. Examples follow:


-  Aurorae with lower borders at elevations between 00 and 100 are listed in the first
   column, as at 19:15 and 19:30 when a medium intensity glow was seen at the northern
   horizon.

-  Aurorae with lower borders between 100 and 14ø are listed in the second column. The
   only entry shows no aurora in this region at 19:15, at 19:30 the glow to the north
   had spread above 10ø but since the glow was listed in the 0° to 10° region, no
   separate listing of it is made in the 10° to 14° region.

-  Most of the display occupied the 14ø to 21ø region of the sky. A medium homogeneous
   arc was seen at 19:00. By 18:15 the arc had a red lower border. The homogeneous
   arc had changed into a rayed arc with short rays by 18:45. At 19:15 the homo-
   geneous arc reappeared, weakening and becoming very quiet by 20:00. After 20:30
   no aurora was observed in this region.

-  The sky between 21° and 32° contained the lower borders of several aurora. At 19:15
   a medium rayed arc with fainter rays occupied this region persisting past 19:30 and
   observed again at 20:30 when its colour was green; at this time motion was noted
   along the arc moving eastward. At 22:00 a medium green yellow quiet homogeneous
   arc was awarent in the sky between 21° and 32°.

-  At 19:30 long rays appeared in the north-eastern sky extending close to the zenith;
   since these rays originated near the extreme end of the rayed arc listed in the 21°
   to 32° region, they are noted only under the remarks column. On the other hand,
   rays were noted at 20:30 which were independent of all other listed forms. These
   separate rays are in the region 32° to 62° where their lower borders were noted.

The use of these forms should prove helpful to aurora observers, both as a personal
record of their work and also for supplying data to the Society. Most Centres should
be able to stencil their own versions of these; however, smaller Centres may wish to
procure copies from larger Centres such as Edmont on and Montreal where aurora programs
are well established.

Observers who experience difficulty with the format and use of these two Loins are
referred to the N.R.C. Bulletin "I.G.Y. Visual Aurora Program for Canada, General In-
structions". Copies may be obtained from the Auroral Centre, National Research
Council, Ottawa, or the National Co-ordinator for the Aurora Program.

                                      Earl Milton, National Co-ordinator,
                                      Aurora Section,
                                      Standing Committee on Observational Activities,
                                      2 Spence Street, Apt. 12,
July 1966.                            Regina, Sask.