MANUAL
for GLORIA project TAD telescope users
Introduction – basic information on the telescope
The TAD [Generally Available Telescope - TelescopioAbiertoDivulgación] is used for solar photosphere observations and is located in Tenerife, the largest of the Canary Islands which are a Spanish Autonomous Region. The observatory, located on the hillside of the Teide volcano, has worked incessantly since 1964. Its location provides good weather conditions and perfectly clear air due to its high altitude (2400 m above sea level). A refractorLunt Solar System optic tube (using lens) with an aperture of 152 mm and a focal distance of 900 mm is installed on a German-type equatorial mount. It is equipped witha broadband objective lens solar filter and the images are recorded using a CCD camera with a resolution of 1280 x 960 pixels. But for the experiment, the images are taken with the finder which is a BORG 77ED of 77 mm in diameter, with a focal length of 500 mm, and a system of image acquisition using a CCD camera 1280 x 960 pixels. Since the diameter of the Sun's disc image in the telescope focus is 840 pixels, the angular resolution of the whole system is 1.45º (the diameter of the Earth seen from the Sun's distance would be about eight pixels). Every Internet user may gain access to the telescope by creating their account on the GLORIA project website. Each observation session (or "experiment") lasts 15 minutes and the users can make observations between 15.00 and 19.00 UT, which for us is afternoon and early evening. Output data formats are fits and jpg. Note: the system does not archive the images, so you should download them to your server immediately after taking the images.
Part one – general rules on the use of the TAD
Section 1 – creating an account, reserving experiment time
After entering the address: gloria-project.eu in the web browser, you will see the GLORIA project home page:
Select a language by clicking the appropriate flagin the top right corner. Open the "USER COMMUNITY" subpage to create an account:
Select "Sign In" to create a new account:
You are required to fill in four fields: name, user's name (login), Email address and CAPTCHA code.
The reply, i.e. the access password, is sent almost immediately; you should sign in using the received password, accept the rules and regulations. You absolutely must change the password to a password of your own:
We recommend using the "Remember Me" option, especially when you are using a dedicated computer.
From that moment, you have full access to the telescope, so you can reserve observation (experiment) time. To this end, enter the "Online Experiments" tab.
A reservation window will appear where you can see the dates of available 15 minute observation sessions. Before that, select "SOLAR" and "TAD" options from the drop down menu. At present, they are the only available options. Indicate the appropriate field with date and time (UT) to select the specific session, and click the "Reserve" button to confirm:
One user may reserve up to four sessions, and it does not matter if they are consecutive or take place on various days.
When you click "Update reservations", your current reservations log, i.e. list of reserved sessions, will appear at the top:
From now on you are a full user of the GLORIA TADand may carry out your own observations of the solar photosphere within the reserved time.
Section 2 – carrying out an observation session (experiment) and recording the results
Bearing in mind that the reservation times are expressed in UT (in summer, the difference between our local time and UT is two hours, and in winter it is one hour), sign in on the GLORIA project website at the correct time and select the Online experiments tab to display your observations log:
If you click the Actions button, two options will be shown:
You may give up on a session at any time by clicking Delete, but if you decide to go ahead with the session as planned, select Go to access the telescope steering window. However, if you do it too early, i.e. before your session starts, an appropriate message will appear:
You will only need to wait until the time comes and then click Go to access the telescope steering interface:
On the left side of the screen you can see two windows with images from web cameras. The top one shows an image of the telescope dome from the external camera - the roof will open when you clicktheWatch the SUN button. The second window is an image of the telescope from inside the dome against the sky background – you will see it move to target the Sun. The middle panel consists a view window – this is where the Sun's disc will appear, as well as rows showing the values of the following parameters: brightness, gain and exposure time. The last parameter is particularly important – selection of the proper shutter speed is prerequisite for taking a good photo.
Once the telescope has targeted the Sun, the image of the Sun's disk should appear in the Wide field window. This image comes from the seeker - a small Sun seeking telescope:
When you click the Narrow field button, the Sun's disc image should appear in the window. If there are heavy clouds present, the image will be blurred and vague. If this is the case, you should simply quit the session as the results will not be satisfactory anyway. If the weather is good, check whether you can see the whole image of the Sun (if not, use the green arrows, bearing in mind that the image will move in the opposite direction):
You have no guarantee that the previous user has left the telescope properly adjusted. Therefore, you should check the focus and exposure time. To this end, use the buttons of the "Focuser" window and enter new values in the "Exposure time" row, confirming them by clicking the Save button. The "Status" row informs you whether your action has been completed successfully:
After each change of focus or exposure time it is useful to carry out an observation by clicking theTake image button. A full-format image of the Sun's disc will appear on the screen:
If the exposure time has been set correctly, the Sun's disc should be yellowish without overexposure in the central part. You should also see clearly that the disc gets less and less bright towards the edges. Note: you should not be afraid of underexposure; overexposure of the image is much worse. If the focus has been set correctly, darker solar spots should stand out distinctly against the uniform background (provided that solar spots are present during the experiment). Visible umbra and penumbra are a good criterion of the image's quality. Visible lighter spots, i.e. faculae on the edge of the Sun's disc image indicate thehighest image quality.
Now it is time to decide - if the quality of the image taken is satisfactory, you should save it on the local PC. To this end, you have to choose the format: jpg or fits. We recommend that beginners choose the jpg format – the image saved resembles the one from the window and may be used to calculate the Wolf number or be published on the Internet without any additional processing.
Save the image using the appropriate button and you return to the observation session(experiment) - the number of remaining minutes of your session is shown in the top right corner of the telescope interface. When the session comes to an end, the system will move the telescope to stand-by position and the dome will close.
A proper observation session will result in a series of photos of the solar photosphere with details whose appearance and location keep changing all the time. For example, on May 15th 2013, the solar photosphere looked like this:
You can see the edge darkening and active regions with solar spots and faculae. In the largest spots, you can see umbra and penumbra areas. Such an image may be used to calculate the Wolf number on the considered day.
You may get the following messages when trying to access the telescope:
If this is the case, you should try again and if this does not help, you should sign out
and sign in again. The system is still being tested and errors are eliminated as soon as possible; however, they still happen from time to time.
Prepared by Grzegorz Sęk, Youth Astronomical Observatory in Niepołomice
Jolanta Olejniczak, School Complex No 5 in Stargard Szczeciński