Hints, bugs, and recovering from errors

Several bugs remain in JObserve version 1.7.4, some of which are mentioned in this document and can be worked around until they are fixed in a future version. Other known bugs are listed at http://www.aoc.nrao.edu/software/jobserve/Known_Bugs/.

Some of these bugs may commonly affect users:

1. JObserve version 1.7.4 does not interpret TIP scans correctly. If Tipping procedure is specified as the Observing Mode on the Source Page, then the positions entered in the Right Ascension and Declination fields are interpreted by the VLA online system as azimuth (in "hh mm ss.sss" format) and elevation, respectively. However, JObserve takes these to be R.A. and Dec., calculating slew times erroneously, listing incorrect azimuths and elevations on the Scheduling Page, and possibly reporting other errors. There are several ways to work around this problem, and perhaps the most straightfoward is to experiment with a Right Ascension and Declination on the Source Page to give the desired starting azimuth and elevation on the Scheduling Page so that the calculated slew times are correct, and then to edit this scan in the final observe file replacing the R.A. and Dec. with the desired starting azimuth and elevation in the correct format.

2. When making changes or updates to a scan in the User Default List, the changes do not propagate to the scans in other lists that use this User Default. The best way to work around this problem is to create a new, updated, User Default and insert this into the relevant scans, or to try Global or Block edits.

3. Qualifiers and Comments on the Source Page are "sticky," in that once they have been set it is not possible to reset them to blank by editing the relevant field on the Source Page. They can be replaced with different text, but not with blank spaces. The only way to remove completely a Qualifier or Comment from a scan is to save the environment files, exit from JObserve, edit the relevant environment file, and restart JObserve with the edited environment files.

4. The Special Instructions on the Starting Conditions Page is limited to 4 lines of comments. If you attempt to exit the Starting Conditions Page with more than 4 lines of text in the Special Instructions field you will generate Java errors.

5. If the start date on the Starting Conditions Page is changed then Compute Observing schedule (from the Schedule menu) or Reschedule (on the Scheduling Page) needs to be run twice in order for the sky frequency on the Freq Calculations Page to be updated.

6. The calculation of the sky frequency in JObserve for Doppler tracked observations is slightly different from that of the VLA online system. A more accurate calculation can be found by using the Online Dopset Tool at http://www.vla.nrao.edu/astro/guides/dopset/.

7. Occasionally Java errors can occur when trying to exit a page by selecting Done. The origin of these errors have been difficult to track down to date, because they seem not to be reproducible. To exit the page you must select Cancel, although your edits on that page will be lost.

If you find other problems or errors with JObserve version 1.7.4 please first check that they are reproducible, then send email describing the problem to jobserve@nrao.edu.