I. How do I find regions of the sky that have been observed in optical
wavelengths more than once?
1. Using the NOAO-Sky viewer, click the "archive" called "Repeats"
- You will see a gray-scale image under the sky grid. Each pixel is
color-coded in order to indicate the number of times that region has
been observed (there is a key on the bottom right of the viewer).
2. Choose a location (by holding down the mouse-button and dragging the
map in any direction) and a zoom level (via the slider at the top
left of the viewer).
- As you zoom in on a region of interest (in this case, a region of
the sky with bright pixels) and drag the mouse (with the button
pressed), the map should slowly move across the viewer. You may need
to wait a few seconds for additional map images to load into your
viewer.
3. Choose to Display Wireframes from any of the other ground-based
(NSA/SDSS/CNOC) archives on the list (at the bottom of the viewer).
- You will see wire-frames for those archives appear in the viewer.
4. Once you reached zoom level 6, you can click the "New Search" button
(at the bottom right of the viewer).
- You will see a list of available images within the RA/Dec range and
for the given archives selected (those with a check in the box).
5. Double Click your mouse over the wireframes.
- You will see a list (below the viewer) of the available image data.
6. If you are beyond zoom level 6, choose a different archive from the
list and click "New Search".
- You will see a list of data products below the viewer. Only those
archives selected will appear.
7. Zoom in far enough such that the region of interest encompasses most
of the viewer.
- Each time you zoom in, you will need to click the "Search" again to
see the metadata of the available images. If you do not wish to see
these metadata, turn search off using the List On/Off box.
8. Click here for a step-by-step pictorial example.
II. On what dates were these images taken?
1. Make sure you are at zoom level > 6 and click the "New Search" button
(at the bottom of the viewer).
- One of the columns in the list is the DATEOBS (if provided by the
archive). You may sort on DATEOBS by clicking on the column header.
2. Once you have the NOAO-Sky positioned and zoomed where you like
it, click on the check-box next to NOAO-Sky (on the top far-left).
- This will turn on "Persistence" in the sky. This means that
the RA/DEC range of the viewer is carried over (persisted) to
the other views (e.g., Time, Access, Analyze).
3. Now, click on the NOAO-Time link (on far left).
- You will switch screens to a Calendar view (a monthly timeline
at the top and a daily calendar view in the rest of the screen.
Blue months/days are those which contain date in the RA/DEC
regions of your NOAO-Sky view.
4. You can choose a month and year in the form (top of the page). For
example, type 2000/05 in the box next to the Go to Month, then click
the button "Go to Month".
- Your calendar will "zoom" to that year and that Month. You should
see data from the First Look Survey.
5. Click Next to an Archive (located at the top of the calendar)
- Since you have Sky "Persistence" turned-on, your data-product
view shows metadata for all images using the RA/DEC range from
your previous view on the Sky. Since you are in the time view,
an additional constraint on the time is also included on the search.
Finally, by specifying an archive, only data from that archive
will appear on the Calender.
6. Click on an individual Archive/Survey link on any given day.
- You will see this specific data taken on this specific data. Since
you have Sky "Persistence" turned on, an additional constraint
in RA/DEC from your last NOAO-Sky view window is applied.
7. Click months (or arrows) to move forward or backward in time.
- Each time you move forward or backwards, you will see
days and months with data. Days in the calendar also indicate
which Archive/Survey they are from.
8. Un-check the box next to NOAO-Sky
- This turns Sky "Persistence" Off. Your searches no longer
include the constraints from your last NOAO-Sky view. Your
calendar should automatically reset to the current month/year/
III. How do I download those images to my local machine?
1. When you find an image you want to access FITs, click "Search".
- You will see a list of data products below the NOAO-Sky.
2. Add it to the Shopping Cart by checking the box.
- The option to add this image to the Cart will disappear.
3. Once you have the image(s) you want to download in your Shopping
Cart, Click the "Access" button.
- You will be able to simply click on the link to any image to download
4. OR: Click "Stage" to stage all of the images in your shopping cart.
- The NOAO VO Portal will download all of the files you selected to a
staging area at the Portal. These files will be accessible via FTP to a
location specified by the Portal with instructions.
5. OR: Click on the Aladin Link and view/download through Aladin
6. Click here for a step-by-step pictorial example.