Central Bureau for Astronomical Telegrams

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Accessing Web Computer Services

We now offer access to the Web Computer Services by both username and password entry, and by IP address. A summary of the two access modes follows.


When you begin a subscription, you will receive by e-mail details on your username and password.
  • When you try to access a protected page, you will be prompted for your username and password. Both username and password are case sensitive.
  • The username/password mode of access is the only option if your IP address is dynamically (or semi-permanently) allocated by your ISP.
  • The subscriber should ensure that the username and password are stored in a secure and convenient location.
  • Your username and password are communicated to you by e-mail when your account is setup. The username is referred to as the WebCS id in older messages. The same username is used for the CS and the ECS, but each set of services has a different password.

IP Address

The advantage of using IP addresses to allow access is that the subscriber does not need to remember or enter a username and password. It is the subscriber's responsibility to inform us from which IP address(es) they want to access the services when the subscription begins or is renewed.
  • Use of this access mode requires that the subscriber has a permanent IP address.
  • It is a requirement of CS access that an e-mail delivery address for the circulars be supplied.
  • IP access will be available to both individuals and institutions.
  • IP access can be granted to a single IP address (i.e., a.b.c.d) or domains (i.e., a.b.c.* or a.b.*.*).
  • Granting access to domains requires the subscriber to have an appropriate license type: a type 1 license will not suffice.
    • If you wish "n" single-user machines to have access, you will require a license that allows at least "n" users.
  • An appropriate license type is also required for single IP addresses located in libraries or common-access areas.
    • Most institutions will require a type 12 license for common-access machines. Small institutions may only need a smaller license type. In such cases, the total staff/enrollment of the institution is to be treated as the "number of readers": e.g., a 15-member institution would require a type 3 license.
  • If domain-access is granted, then we will periodically audit the access from that domain. If the number of machines accessing the services is larger than the number allowed by the license, you will either need to obtain a larger license or we will restrict access to individual IP addresses (the number being determined by your current license).
  • The ECS is not currently accessible using IP address validation.
If you wish to take advantage of this access mode, you must send a list of IP addresses or domains (NOTE: not host names) that desire access, along with the account number, to iausubs@cfa.harvard.edu. In addition, a declaration of the nature of the machine for which access is being requested is required: either "This is a single-user machine" or "This is a public-access machine". Failure to include such a declaration will cause your request to be ignored, as will a failure to include the account number and desired IP address(es).

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