Having the star analyser installed in a filter wheel of my slow (f/9.4) and low budget imaging system https://www.cloudyni...-100/?p=9742246), I'm always in search for objects that are
1) astrophysically interesting,
2) bright enough (m<11 mag] and
3) are rewarding objects for doing low resolution slitless spectroscopy AND astrophotography (once the object is on the sensor, both aquisitions can be made consecutively without changing the system by simply turning the filter wheel)
The famous Blue Snowball (NGC 7662) is such an object: Low-ionisation emission regions and other microstructures can be imaged in this bright planetary nebula and a low resolution spectrum can be recorded due to its relatively small diameter:
For plasma diagnostics the [O III] lines around 5000 Angstrom should be resolved. However, in my spectrum this is not the case. Only a shoulder is visible. The first derivative of the spectrum reveals the overlaped lines (keeping well in mind that star analyser spectra of non stellar objects should normally not be processed in this way: https://www.cloudyni...tive/?p=9721131
After background and continuum subtraction the Balmer decrement was calculated. The excitation class was calculated by assuming that the area under the non-resolved [O III] lines can be used as a measure for the sum of N1 and N2:
The same object recorded with superior equipment:
Here are some other examples of rewarding objects:
Hubble's variable nebula NGC 2261 (no star analyser spectra found so far) - to be recorded
The Pleiades (B and Be stars) - to be recorded
Thor's Helmet with its central Wolf-Rayet star - to be recorded
More suggestions are highly welcome! I'm slowly running out of objects....
Edited by mwr, 11 January 2020 - 01:38 PM.