IAU Central Bureau for Astronomical Telegrams

Central Bureau for Astronomical Telegrams -- Image credits

How to Submit CCD Images in Support of a Discovery Claim

Please DO NOT send ANY images unless FIRST requested to do so by Bureau staff! It is preferable that you post your images on your own website and then send us the URL to view them.

The Central Bureau for Astronomical Telegrams can now accept CCD images in support of discovery claims. Details on how to accomplish this are given below, should you be requested to send such images. Please ensure that you read all these notes carefully before submitting images.

Note that the Minor Planet Center cannot accept images of new minor planets for measurement--it is the observer's responsibility to obtain accurate coordinates. Claims for new discoveries of minor planets are not accepted unless there are precise astrometric measures on two nights.

Images not sent in a fashion consistent with the following guidelines may be ignored. If you cannot be bothered to follow our guidelines, we will not waste our time decoding and examining your images.

How Do I Transmit The Images?

Images may be sent via e-mail, ftp or on diskette. Acceptable image formats are listed below. The type of image should be indicated in the accompanying text to avoid the possibility of confusion.

Images should not be sent by FAX, as the reproduction of images is generally very poor.

Via e-mail

Images sent via e-mail must be encoded to avoid the need to transmit 8-bit characters. Such images should be UUENCODEd. You are asked not to use other encoding methods, especially BASE64 encoding. Users of MIME-compliant mailers are asked to ensure that BASE64 encoding is disabled.

Each image file should be sent as a separate file--do not concatenate multiple image files into one e-mail message.

Via ftp

Images may also be ftp'd to our anonymous ftp server. Exactly how you would ftp an image file is dependent on your software. The general steps are as follows:

  • connect to cfa-ftp.harvard.edu (IP number
  • log in as anonymous and give your e-mail address as a password
  • change directory to "incoming/graff"
  • change transfer mode to binary
  • put the file
  • disconnect

Note that you cannot list the contents of the incoming/graff directory. The text of the discovery report should be sent via e-mail and should indicate there is an image file on the ftp site and note the file's name.

On diskette

Images may be sent on the following types and formats of diskette:

  • 3.5-inch diskettes
    • 800K Acorn ADFS
    • 640K Acorn ADFS
    • 720K Atari
    • 720K Atari
    • 720K MS-DOS
    • 360K MS-DOS
  • 5.25-inch diskettes
    • 320K MS-DOS

We cannot accept high-density diskettes as it is currently very difficult for us to read high-density diskettes of any format. We hope this restriction will be lifted in the near future.

We regret that we cannot return diskettes.

What Image Formats are Acceptable?

Images can be accepted in a variety of formats:

  • 8-, 16- and 32-bit integer FITS
  • SBIG ST-4
  • SBIG ST-x (i.e., ST-4x, ST-5, ST-6, ST-7 and ST-8)
  • Starlight Xpress SX8 and SX8L

Support for native formats of other makes of CCD camera (e.g., Meade Pictor, Axiom AX, HiSIS, Spectrasource Lynxx, etc.) will be added when documentation on their proprietary formats is made available to us. Manufacturers wishing us to support their cameras should use the feedback form to send us the necessary documentation and sample images (or tell us where to obtain such information on the WWW).

What Image Formats are Unacceptable?

Any formats not mentioned explicitly in the preceding section should not be used. However, due to their popularity the following formats are specifically noted as being NOT ACCEPTABLE:
  • GIF
  • TIFF
  • BMP

What About Image Size and Depth?

You should avoid sending very large files (2048 x 2048 32-bit FITS file = 16 MB). If necessary, reduce the depth of the image (reducing the example image to 16-bit FITS halves the size), extract only the relevant portion of the image or bin pixels. Please bear in mind that it is rarely, if ever, necessary to use 32-bit resolution files of any type.

How Many Images Should I Send?

As few as possible in order to make your point. Be very selective in what you send. In particular, our ftp space (which is on a machine that is not ours!) has limited space.

What Processing Should be Done on Images?

Processing of the images should be minimal:
  • images should be clean (i.e., unbiased and flat-fielded)
  • no other processing (e.g., smoothing, stretching, etc.) should be done.
  • positions of objects of interest (e.g., the subject of the discovery claim) should be noted as pixel x,y coordinates in an accompanying text message and should not be marked on the image.

What About Accompanying Documentation?

Accompanying documentations should include the information normally expected for a discovery report.

In addition, the orientation of the CCD image should be noted, specifically which direction in the image is north and which is east.

Indicate on how many images the suspect appears. This is very important as you should not report suspects on single images. Be selective in the images you send, e.g., for a nova/supernova suspect send one image from each night.


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