Hoping for help from the LHiRes community: I noticed some trouble with strange line profiles. After a long time of observational absence I finally started w/ some work using LHiRes. It is used w/ a 2400l/mm grating and a 23µ slit. A Nova 402 ME is used as the CCD.
The raw image containing the two Neon lines around Ha looks like
TestatHa_5.png [ 395.01 KiB | 412 mal betrachtet ]
A profile taken in IRIS (y=190) is shown here
TestatHa_5_zeile190.png [ 19.33 KiB | 412 mal betrachtet ]
A quick line scan, wavelength calib and Gaussian fits are done in VSpec
TestatHa_5_zeile190_vspec.png [ 64.13 KiB | 412 mal betrachtet ]
I think the issue is easily visible: extremely large "foot" of the lines and - at the same time - a resolution of 6500/0.75=8700 far lower than expected.
I expect something is not properly adjusted, but what?
For sake of completeness two more photos of the distance cam to spectrograph (back focus topic?)
IMG_20180401_174257a.jpg [ 44.1 KiB | 412 mal betrachtet ]
and the position of the doublet.
IMG_20180401_174443a.jpg [ 35.9 KiB | 412 mal betrachtet ]
I am grateful for any advice in advance.