Frequently Asked Questions

How does the archive work?

The first step is to obtain scientifically useful observations of Venus as described in the observing instructions. When the data is prepared, you upload the image (TIFF or FITS format) through the image submission form on this website. If you have not already done so, the image submission page will ask you to login or register as a user.

After you successfully uploaded the image, the system will request you to enter a set of mandatory and optional keywords that describe your observations in a way that is useful for scientists (see the list of keywords). During this process, the keywords will be validated automatically to prevent errors. Once the proper keywords have been entered and validated, you may submit the observation and your image will appear in the Recent Submissions Gallery.

Within a couple of days after submitting the observation, your data will undergo an initial review by an administrator. The administrator will verify if the data meets the minimum criteria and then move the submission to the official Active Archive Gallery. You will be notified of this event by e-mail.

What image formats are accepted?

To ensure that your data is suitable for scientific analysis, we ask you to submit your image in a format without lossy compression (e.g. JPEG-compressed images are not allowed). Two formats are currently accepted:

  • FITS (.fit, .fits)
    FITS is the standard and preferred format for storing astronomical data. FITS-files can be exported from astronomical software such as Registax, Giotto, K3CCDTools and Iris. Free plugins are available for other software such as Photoshop and Irfanview.
    Note that a FITS file may contain multiple data units with different dimensions. Your image of Venus should be the first data unit and have exactly 2 dimensions (i.e. a grayscale image). Archiving keywords may be embedded in the data unit.
     
  • TIFF (.tif, .tiff)
    When it is not possible to submit your data as a FITS file, you may also use TIFF. However, make sure that your TIFF-files don't use a lossy compression scheme (i.e. don't use JPEG-compression inside TIFF!)
    After submission, the archive will automatically convert your TIFF file to a grayscale FITS image.

What are the minimum data criteria?

The data must have been obtained as described in the observing instructions. The most important criteria are:

  • The file should be an uncompressed TIFF or FITS file.
  • The file should contain just one image of Venus (no mosaic).
  • The image should not be a composition of different filters (no advanced post-processing).
  • No text should be added to the image.
  • Values for the mandatory keywords must be provided.
  • Attempt to keep the setup and post-processing steps identical to your other images.

If a problem is spotted, do not worry. We will get in contact with you to help you correct the problem.

 

What image post-processing steps are allowed?

Image processing generally includes the selection of sharp frames from video, followed by alignment & stacking of individual images to reduce noise. This is typically performed using software like Registax or Giotto. It is important to note that you may only stack exposures that were obtained using an identical filter and telescope setup. It is not allowed to submit images where exposures from different filter setups have been stacked or otherwise combined, as such images are difficult to analyze in a scientific way.

Other post processing steps such as wavelets or unsharp masking may be used to reveal fine detail. However, care should be taken to prevent introduction of processing artifacts (e.g. artificial bright edges). Any of these post-processing steps should be mentioned in detail during the submission of an image.

 

What about my mosaic product or color composition?

As mentioned above, we aim for non-composed images. We recognize that mosaic products and (color) compositions offer interesting insights, but the original images are required for proper scientific analysis. However, we do allow you to upload processed results after uploading the original images (see the "Processed Images" gallery) and also encourage you to submit processed results to the Amateur Gallery at the University of Wisconsin-Madison , the Venus section of the British Astronomical Association coordinated by Dr Richard McKim and the Association of Lunar and Planetary Observers.

 

When should the data have been obtained?

We welcome all observations taken from 2005 onwards. By uploading this part of your archive, you allow your ground-based results to be compared with the observations made by the Venus Express spacecraft in the same period.

 

Can I edit or withdraw my data?

Yes, you can edit your data while it is in the Recent Submission Gallery. Make sure you are logged in, click on your image and click the "Edit keywords" or "Withdraw image" buttons to the right of the image. If the image has already been moved to the Active Archive Gallery, you can no longer edit the data. In this case, you must contact the administrator.

 

I cannot find an answer to my question?

Please contact us at vaa@rssd.esa.int. We are happy to assist you!