Required Information
Identification
We need your email address to send you your results.
Field to solve: select one of the following:
In order to solve your field, we need either an image of your
field (as a FITS, JPEG, GIF, PNG file or a URL); OR a list of star
positions (as a FITS binary table or text file).
Image file:
Your JPEG, GIF, PNG, or FITS image. Must be less than 250 MB!
Image URL:
The URL of a JPEG, GIF, PNG, or FITS image. Must be less than 250 MB!
FITS binary table:
Must contain a BINTABLE of detected objects, with X and Y
pixel positions in "D" (double) or "E" (float) columns, with
one object per row.
The rows must be sorted by brightness with
the brightest object first.
Text file:
A text file, containing two columns of digits separated by commas or whitespace,
listing the X,Y positions of sources, sorted with the brightest sources first.
Scale of the image:
If you provide an estimate of the size of your field, our search will be much
faster. Most digital-camera images are at least 10 degrees wide;
most professional-grade telescopes are narrower than 2 degrees.
Optional Settings
Parity of your image
Flipping an image reverses its "parity". If you point a digital camera at the
sky and submit the JPEG, it probably has negative parity. If you have a
FITS image, it probably has positive parity. Selecting the right parity
will make the solving process run faster, but if in doubt just try both.
Index to use
We use indexes to solve your fields;
an index contains "landmarks" for the sky.
The solving process works best when the "landmarks" are a little
smaller than the size of the field to be solved.
We can automatically choose a suitable index based on your pixel scale estimate,
or you can select one here.
Automatic (based on image scale)
90-degree Fields
60-degree Fields
45-degree Fields
30-degree Fields
25-degree Fields
15-degree Fields
10-degree Fields
8-degree Fields
5-degree Fields
4-degree Fields
2.5-degree Fields
2-degree Fields
1.5-degree Fields
1-degree Fields
40-arcmin Fields
30-arcmin Fields
20-arcmin Fields
15-arcmin Fields (eg, Sloan Digital Sky Survey)
10-arcmin Fields
8-arcmin Fields
Star positional error
When we find a matching "landmark", we check to see how many of
the stars in your field match up with stars we know about.
To do this, we need to know how much a star in your field could
have moved from where it should be.
Tweak
After we find a correct match, we can run a "Tweak" process
which tries to fine-tune the World Coordinate System transformation
by computing polynomial SIP correction terms.
Sometimes this process actually makes the solution worse - we are
working on an improved version.
