This page lists your images taken with GRAS telescopes, most recent on top. This list is the staring point for analysis.
It can be filtered, and tools are available to perform various task on the images in the list.
List Contents
The information in the list is extracted from the FITS headers. It contains:
- G: The name of the telescope system
- Object name: This is the name as entered in ACP (or in the ACP script). Click the Object name to start analysing this image. More info here.
- Date/Time: The UT observation date/time of the image (the mid-point time of the exposure)
- R.A.: The R.A. of the true center of the image (corrected by the plate solve)
- Dec: The declination of the true center of the image (corrected by the plate solve)
- Exposure: The exposure time of the image in seconds
- Filter: The name of the filter used in the exposure
- WCS: Shows 'OK' if the image has been plate solved. If OK, Photometrica can import import catalog data and display R.A./Dec.
- Cal: Shows how the image was calibrated (B = bias corrected, D = dark subtracted, F = Flat fielded)
Tools
The following tools are available, which applies to all imags listed:
- Measure All Images: This time series tool lets you analyse
several images at once, for instance to create ligth curves of variable stars. All
images shown in the list that has been plate solved will be analysed. You
need to have one target only, and of one filter. However, the images can be of an
arbitrary time span and taken with one or several telescopes. Click
here for more info.
- Stacking images: Click 'Stack' to stack the images in the list. Note that all images must be of the same dimension.
The images will be averaged into a new image. This new image is shown in the list with bold font. The observation date/time
will be set to the mid-point of all stacked images. Before they are stacked the images are shifted in X and Y direction, but
rotation in not handled.
- Download: Click 'Direct Download' to download the images to your local computer. They will be zipped into a single ZIP archive before they are downloaded.
This method is based on the HTTP protocol, which might not work for large file transfers. It is recommended that you use
this method for files less that about 10 MB in size. Use FTP transfer for larger files.
- FTP Transfer: To download a large amount of files (more than
10 MB in total size), you need to transfer the images to the FTP server. This method
is much more reliable than direct download. You can then download the files from
the FTP server to your local machine. As in direct download, all images are zipped
into a single ZIP archive, so you will only have to download one file from the FTP
server. NOTE: you need Private FTP for this to work.
- Upload images: Click 'Upload Images' to upload old images for re-analysis. Images should be zipped
into a single file to minimize bandwidth load. They will automatically be un-zipped
on the server.
- Removing a single image from the list: Sometimes you might want
to remove a single image from the list. To do this, open the image for inspection
(by clicking the object name link), and then click the 'Exclude and Return' link
in the top menu.
If you check the checkbox 'Display new images as they are uploaded',
new images will automatically be displayed, ready to be analysed, once they are uploaded and available.
Filtering the list
- Filter by observation date: Observation date should be in the form YYDDMM. For instance, 2008-04-20 is entered as 080420.
If only 'From' is specified, all images from that date until today will be listed. If only 'To' is specified, all images up to that date is listed. Both to and from implies a period.
- Filter by object: Enter the object name. This should be exactly
as entered when staring the imaging session in ACP, or the name specified in the
ACP script.
- Filter by photometric filter: Choose between B, V, R, I and Clear
filter.
- Filter by telescope system: Choose GRAS system.
To apply the filter, or to view new files that might have been transferred to the server since last time the list was refreshed, click the 'Refresh list' button.
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