Assuming that you have a telescope, how do you look at the Sun? This is done by PROJECTION, using the telescope to project the image of the Sun onto a piece of white paper or other white surface. The amount of light coming from the Sun is considerable. The projection method allows us the means to observe the Sun in complete safety.
The first thing that you should do is make a projection box, or other means of supporting a white surface behind the eyepiece. A box is a better choice, because it will darken the surrounding area and increase contrast, so you can see smaller detail. But any type of carrier will do. It is best attached to telescope so it will remain behind the eyepiece if you move the telescope. Normally you can attach the projection equipment to the eyepiece, or to the mounting if need be. It must be securely attached and not able to fall off or impede the movement of the telescope. Some observers use home-made projection carriers, others use cardboard boxes - it's really up to you how you mount the white surface. But one thing that is good to know is that projection is easy and above all, cheap and safe! Using a projection screen will often require a second screen near the front of the telescope to darken and hence further increase the contrast of the image, otherwise the surrounding area will be bright and you will not see detail too well.
CAP THE FINDERSCOPE. Attach the projection box or screen to your telescope, then fit a low power eyepiece. Mask off the telescope if required, to take down the amount of light entering the system. Begin to point the telescope in the direction of the Sun. DO NOT LOOK AT THE SUN YOURSELF. Instead, watch the shadow of the telescope on the floor, etc. Once the shadow has become small the telescope will be pointing at the Sun, and this will be confirmed by a diffuse white disc of light within the range of the projected image from the eyepiece, called the THE FIELD OF VIEW. Now focus the telescope using the thumbwheels, or by pushing or pulling the tube, backwards and forwards, until the image has become clear. This is the image of the Sun, and you will, depending on what part of the solar cycle it is, see the darker sunspots somewhere on the white disc. The size of the projected image should be 6 inches (150mm), which is the standard size of image used by observers all over the world. Adjustment of the projection equipment should be made to obtain this size of disc. However, if you can obtain only a 4 inch image, which would be apparent on small focal length telescopes, it will do for a start. As said before, the image of the Sun will move due to the rotation of the Earth, and if you have an altazimuth, movement of the telescope will have to be made every two minutes or so, depending on what magnification is being used at that time. A high magnification will mean that you will have magnified the movement as well as the image. It is amazing how quickly the Sun moves! Try not to knock the telescope as this will require you to realign the telescope and you may miss the observation, especially on a very cloudy day when the Sun is very intermittent.
Try various magnifications to see the image. You can changed magnification of the telescope by changing the eyepiece, to one with a shorter or longer focal length: shorter focal length eyepieces increase magnification. Once you are confident in looking at the solar image then now is the time to record details. It is important that you GET TO KNOW WHAT YOU ARE LOOKING FOR ON THE IMAGE, but this TAKES TIME.
This is getting to the stage where you need to be fairly accurate when drawing the sunspots on the drawing sheets. This can be accomplished quite simply by drawing a grid inside your projection equipment. Using a 2H pencil draw a 6 inch circle on a piece of white card which can be inserted or put on your projection equipment. Onto this circle draw in faint lines, a grid of 1 inch squares. You should also draw another identical grid on a separate piece of card drawn in thick pencil or ink so that the dark lines can be seen through tracing paper or the drawing sheet. First, focus the image on the projection card, ensuring that the image fits the grid inscribed on the card or paper. Let the image of the Sun drift and watch the sunspots move. Turn the projection equipment until the SUNSPOTS FOLLOW OR MOVE PARALLEL TO ONE OF THE LINES. This indicates that the solar image is correctly orientated with N at the top. Finding west is easy, it is merely the direction of image travel. If you have an altazimuth mount you may have to move the telescope every couple of minutes, but with an equatorial mount you can move the telescope in polar axis and follow the Sun (providing that you have correctly pointed the polar axis to north and the axis is at the correct latitude). If you have a motor drive, switch on once the Sun is orientated. Draw onto your tracing paper or drawing sheet the activity you see. Faculae can be seen at the edge of the Sun as lighter patches, and should be marked by dotted lines or yellow crayon or pencil. Drawing sunspot activity can be difficult, especially when you have complex sunspot groups on the image, but practice makes perfect, and you must be patient. Mark the umbra in black and the penumbra in solid lines, then place a plain piece of white paper or card over the screen and look for very faint spots. Of course, if you have a box rather than a screen then fainter spots should show.
Once you have the activity on your drawing, then you should go onto a high magnification to see even fainter activity which you may have missed because it could not be resolved by the previous magnification. Put these on your drawing if you can.
Put on your drawing all the information you can about a spot/spot group ( AR ) if necessary. Then write on the normal information such as the day, date, etc.
If you make a separate larger scale drawing of an interesting AR for example, or photograph it, copies can be sent to the Director with the Monthly Report Form, The date and time ( in UT) must be entered on each one, PLUS the orientation, i.e., N. S, E and W points,
Use the Solar Section Monthly Report Form and on the date of the observation write the time of the observation and then looking at your drawing count the number of Active Regions ( AR's ) that you see, in the North, in the South, and then all together. Enter the numbers on the form, and repeat it each day you observe the Sun.
As well as recording accurately any Active Regions seen, it is a major part of the Section’s programme to count the number of individual sunspots seen in AR’s and add them to the observation record. If an umbra is split into smaller pieces with a clear bright gap between them, each part is classed as a separate spot. Do not count any pale grey areas,large or small. Sunspots show as black, ( their umbras, often surrounded by irregular lighter patcheds known as their penumbras ).
If you can only count the number of AR's that is all right. One point to watch is that an AR is classed as a separate entity if it is 10 degrees apart from another active area. This is measured from the centre of the AR.. AN AREA IS SEPARATE IF 10 DEGREES FROM THE CENTRE OF ACTIVITY. Each marking of longitude (lines going up and down on a Stonyhurst Disc) are 10 degrees apart, so you can, by using the disc, establish if the areas are within 10 degrees. If you cannot use the Stonyhurst Discs then leave the counting to the Director. But please indicate that you wish the Director to reassess your counting.
A copy of your completed Monthly Report Form is sent to the Director not later than the 10th.of the following month, by email or post.. A stamped addressed envelope must accompany all correspondence requiring a reply.
Going down the sheet are numbers which indicate the days of any particular month. Along the top of the sheet, are the various columns which are abbreviated as follows:-
D This is the day of the month. Please adjust according to if there are 30 or 31 days in the month.
UT This is the time of the observation. UT denotes Universal Time, or Greenwich Mean Time. In Summer, during the period when British Summer Time (BST) is in force, deduct one hour from BST to get GMT or UT.
NH This column is sub-divided into two. One is the AR's or ACTIVE REGIONS, S is the amount of SUNSPOTS within the group(s). N denotes the NORTHERN HEMISPHERE of the Sun.
SH As with NH but for recording sunspot activity for the SOUTHERN HEMISPHERE.
S is the total number of individual sunposts in all the AR's observed.
TOTALS This the total of the two columns (NH and SH ) added together (both AR and S added up.)
R This is the SUNSPOT NUMBER, and is found by the formula R=10g+S, where g is the number of groups, and S is the number of spots (example: if the total for a day's observations is 2 active areas and 5 sunspots R=20+5 = 25).
PR This is the number of prominences seen ( for observers with h-alpha filter systems )
To the bottom of the sheet are the TOTALS, which are the totals of each column added up and placed in the corresponding box. Below the totals on the active area columns are three other boxes for MDF. This means MEAN DAILY FREQUENCY. This is a figure which denotes your average solar activity which you have observed. For this to be calculated first count the numbers of observing days you have done and put this figure in the box: Observing days.. What you do now is divide the TOTAL at the bottom of the Active Region columns by the number of observing days and put the result in the respective box. R is calculated by adding up the R nos. column and dividing by the number of observing days.
Place your name, month and year in the boxes above the columns.
ROTATION NUMBERS: . These are the Carrington Rotation Numbers. If you do not know them, leave the boxes blank.
AP This is the the DIAMETER of your telescope lens or mirror.
Px This is magnification of the eyepiece used for the observation.
If the telescope being used is on an altazimuth mounting ( not equatorial ) the N-S axis of the Sun's image will only be correct at noon. Before that the N-S axis will bear to the left, altering from sunrise to noon, after noon in the opposite way.
Also, during the year because of the tilt of the Earth's axis as it orbits the Sun, the Sun's angle will vary, as indicated on this diagram :
Using digital cameras of various types, excellent photographs of solar activity can be obtained. The range of webcams, specialist astronomical cameras, and other digital cameras, software programmes, PC processing programmes etc., now available is now so wide as is their use, attachment to telescopes, settings etc., that instruction on taking solar photographs is not possible in this guide to solar observation. The Director can give details only of the cameras used by Section members.
The SPA Astro Imaging adviser may well be able to offer advice.
Several good books are available that give detailed instructions on all the various aspects of solar observing. The SPA Bookshop gives a selection, and the Director can also give advice about them.
Chapter 4 of this Guide gives further advice on solar observing and recording, plus some solar website suggestions,