X-ray satellite data extraction

xisextract

problem: Can't locate common_functions.pm in @INC (@INC contains: /data/system/software/headas/heasoft-6.13/
solution: common_functions.pn are useful functions used by xisextract and originate in XMM's science analysis software (SAS) that has to be sourced via source $SOFTDIR/sas_init.csh

xmmprepare / xmmextract

problem: No eventfile found in /home/user/.../obsid/pn/raw -- aborting
solution: In some cases an Observational Data File (ODF) is split into more than one observation which makes our scripts fail. See [1] for the solution!! And never forget to source $SOFTDIR/sas_init.csh!

ISIS

fits_save_fit

problem: fits_save_fit writes too long string (exceeding allowed ASCII length) especially in case of many loaded datasets
solution: internally, fits_save_fit gets the binning infos from get_data_info(idx).rebin and converts it to a human readable string stating each interval that is binned differently. In case of a simple rebin_data or group command on the current grid, that will create a huge string as every bin of the current grid will be rebinned separately. You can avoid that by defining a custom grid (example by Matthias Kuehnel):

(eb,)=log_grid(.5,10,5); % energy grid (.5-10 keV, 5 bins)
mc = int(sqrt(eb*100)); % number of channels in each energy bin (factor 100 somehow is the binning "strength")
group(all_data; min_chan = mc, bounds = eb, unit = "kev");

The resulting string will now only have 5 stated intervals

Firmware 50cm Telescope

problem: Pointing in RA is very bad
solution: Check if the time, set in the Handpad, is still correct. The built-in quartz-clock isn't accurate at all and a time difference of up to 30sec in two weeks is possible. I recommend the website "uhrzeit.org" to get the right time. Please note, that the Handpad is still set (and will stay set) to "Daylight Saving"

problem: startrails, even with short exposure times
solution: It seems that the tracking speed of the mount has a temperature dependance. Especially at cold temperatures, the normal speed ist no longer accurate enough. A coorection factor can be set in the Handpad (DRIVE → Tracking cor.). To calculate the correction factor one has to take an exposure with startrails (dual tracking off) and calculate the difference between the normal tracking speed an the speed the mount uses. For this purpose, a Python3 programm is available (Schindewolf).

Guiding with the 50cm Telescope

Always use a crossover ST4 cable for guiding the 10Micron mount with the ST-i Guider or the internal guiding chip of the STX. As the internal wiring of the ST4 ports of camera and mount is different, a normal ST4 cable could cause trouble. With a crossover cable, the correct pins are connected with each other! The cable in the St-i case is crossover for example. If you are unsure theck the coloring of the pins, visible through the clear connector.

CCD Ops

problem: Ghost images on darks or flats with the STX 16803
solution: The Ghost images are caused by the architecture of the CCD (Fullframe). They occur when electrons are not "moved away/deleted" after the readout but stay in the pixel. One possibilityis to wait about 10-20 min or do a "NIR-Preflash" (NIR=Near Infrared). This option can be found in the Camera Menu → STX → properties. But be careful: Once you use it for one picture, you have to use it for every picture of one night. Otherwise the darks and flats would not work correctly anymore as the value of the noise and the response of the pixel changes.

Trouble shooting

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