NAOS Preparation Software: FAQ and Bug Reports

This page contains information about the Preparation Software (PS) which is used to define the optimal NAOS configuration, estimate performance and provide input to P2PP and the CONICA ETC.

To install the the PS software, please visit the PS web page .

To learn how to use the PS software, please consult the NAOS/CONICA Documentation.

Release Notes

Here are the release notes for the NAOS PS. We are currently working on fixing the known bugs for later releases of the PS.

v1.102 - The interaction with the ETC is now improved, and works in both directions. That is, the ETC and NAOS-PS interact
- by loading the NAOS-PS-generated HTML file into your favorite web browser, or
- when calling the ETC directly (the ETC now queries the NAOS-PS server for on-the-fly performance estimates).
v1.97 - The user now has the ability to enter the visual extinction towards their AO reference target. Other minor changes were made.
v1.93 - The proper motions, epoch, and equinox are now properly handled. In addition, the LGS is implemented.
v1.78 - Checksum in NAOS parameter files now correctly computed for non-Linux java platforms.
v1.77 - NAOS parameter files now include a checksum parameter to prevent accidental corruption of the data contained in the .aocfg files; server modifications now preclude rare nonsensical filter/dichroic optimal choices.
v1.75 - fixed possible problems for systems with default language other than English.
v1.74 - A bug in v1.73 has been repaired.
v1.73 - A lot of news.
v1.73 - Session, AO config, PSF, ETC files can have user defined names, not necessarily equal to the target name.
v1.73 - A problem with characters present in tracking tables, was fixed.
v1.73 - N90C10 dichroic can be selected with VIS WFS.
v1.73 - Wind speed default value changed to 12 m/s to reflect real conditions in Paranal over last years.
v1.73 - Tracking table format is displayed consistently in HHMMSS.SS format.
v1.73 - A warning message is sent when N90C10 + VIS WFS is selected by the user, telling that CONICA transmission is very low for that configuration.

v1.62 - In case a very red reference object is selected (for example: K=13 mag, T=1200 K), the PS will return an invalid configuration for the K band filter, using the JHK dichroic. An easy check is the transmission to CONICA: it should always be higher than 3%.

v1.55 - Missing data for some filters and spectral types in the "Reference Objects" sub-panel. For example, the L and M bands and all spectral types. If you wish to use L and M band magnitudes, then use the black body temperature as an alternative to the spectral type.
v1.55 - If the LW filters are chosen in the Target and instrument setup field, then the following message appears in the dialog box "Choice for Dichroic/WFS is not optimal (considering constraints on these elements and/or required minimum transmission". This message can be ignored.
v1.55 - Non-symmetric PSF for on-axis Strehl Ratio. No solution at this stage. For the purpose of using the PSF for exposure time estimates with the CONICA ETC, this bug can be ignored.

FAQ

Is it necessary to set both the 'Dichroic' and the WFS, or even just one ?
Can I select a wrong configuration ?
How does the PS server select the dichroic when I choose the 'FREE' option ?
How can I get the PS to work for reference objects that are fainter than V=16.5 ?
How can I get PS to work for reference objects that are further than 55 arcseconds from the target ?
How can I force the use of a specific WFS or dichroic (for instance: IR)?
Can I put an additional neutral density filters into the WFS light path (for instance to make observations of a PSF reference star) ?
What is the minimum transmission to CONICA possible to use?
I would like to generate automatic .aocfg files without using the Preparation Software tool...
I forgot to save my session (.jnps file), I only have the .aocfg file and I would like to modify it without doing all again...
I would like to use the Laser Guide Star even though I didn't propose to use it. Is that possible?

Question: Is it necessary to set both the 'Dichroic' and the WFS, or even just one ?

Answer: No. In general, the user will leave these options to FREE (see next questions). However, it is now possible to force the use of a dichroic, a WFS, or both. Usually one does not want to do that, but there may be a good reason to want it done. For instance, to observe an extremely red target, without the use of the Neutral Density filter for CONICA, one may select the N90C10 dichroic so that transmission to CONICA is only ~10%. It is possible to use this dichroic with both WFS.

Question: Can I select a wrong configuration ?

Answer:

Question: How does the PS server select the dichroic when I choose the 'FREE' option ?

Answer: First, the PS server will select from only those dichroics compatible with the selected CONICA filter. Then the PS server will return the configuration of dichroic and WFS giving the maximum Strehl ratio. This means that since the selected configuration depends on the flux incident on the WFS, the PS server will never choose a dichroic which favors CONICA (like the N20C80). To use such a dichoic, one must select it explicitly.

Question: How can I get the PS to work for reference objects that are fainter than V=16.5 ?

Answer: You cannot. Although we can sometimes close the loop on objects fainter than V=16.5, it is on the border of feasibility. If you wish to use objects fainter than V=16.5 as references, then use 16.5 as the magnitude of the reference and put a note in your README file that you have done this. We will try to close the loop, but we cannot guarantee that we will be successful. Furthermore, the Strehl ratio the PS then predicts will be an overestimate. The absolute limit is V=18.

Question: How can I get PS to work for reference objects that are further than 55 arcseconds from the target ?

Answer: You cannot. You can cheat by entering a target co-ordinate which keeps your target in the field of view. However, the Strehl ratio the PS then predicts is an overestimate. Additionally, you will have to pay very special attention to where the object may land on the array and this will depend on the camera you choose to use and the offset sequence of the template. If you choose this method, we cannot guarantee the success of your observations.

Question: How can I force the use of a specific WFS or dichroic (for instance: IR)?

Answer: In most cases you should not need to do this. However, in the case of standard star OBs, where one should observe the standard and the science target with the same dichroic, one can force the PS to use the IR dichroic by setting the spectral type of the star to one that is either very red or very cool. In this case, it is very important that the correct IR magnitude is used.

Question: Can I put an additional neutral density filters into the WFS light path (for instance to make observations of a PSF reference star) ?

Answer: You cannot. Although there are two neutral density filters for the visible WFS (only), they are automatically setup by the system for a given configuration. The best solution is to find a PSF reference star which gives a similar correction to that obtained with the science object, using the same dichroic and WFS.

Question: What is the minimum transmission to CONICA possible to use?

Answer: It is 5.1% with N90C10 and filter Ks, 4.2% with N90C10 and filter H, 3.7% with N90C10 and filter J. To reduce the transmission to CONICA if the object is too bright, two neutral density filters are available.

Question: I would like to generate automatic .aocfg files without using the Preparation Software tool...

Answer:You cannot. Users must use the Preparation Software to generate correct .aocfg files.

Question: I forgot to save my session (.jnps file), I only have the .aocfg file and I would like to modify it without doing all again...

Answer: You cannot modify the .aocfg file manually, because it may become corrupted. But there is a solution: suppose your file is named saturn.aocfg then copy it to saturn.jnps and then load this file into the Preparation Software. Don't forget to redo the optimization before you export to P2PP if you apply any change. That's it.

Question: I would like to use the Laser Guide Star even though I didn't propose to use it. Is that possible?

Answer: Sorry, but this is not possible. If you want to use the Laser Guide Star Facility you must specify it in the proposal.