[bojan]

After a long time I tried some spectroscopy with my "new" spectrometer, based on Star Analyser and 4° prism, obtained from BXoptic (China) for less than half the price of Edmund Optic, but similar/same quality (will post the construction detals later).


Balmer series and He line are very easy to identify as they are dominant emissions in the etaCar spectrum.
Interesting detail is the Helium emission (or, at least the wavelength if the "bump" between Halpha and Hbeta suggests it is He).
This spectrum is quite different from spectra obtained by others in different time.... it seems eta is very volatile place.

Relatively low resolution is probably the consequence of the grism place (between MTO lens and Canon camera), where the beam diameter is relatively small (~5mm only). Placing it further away from sensor would increase the resolution, but this will be difficult to achieve because of the diameter of the prism (38mm).
Also, MTO 10_1100 is probably not the sharpest lens there is... my 10" Newtonian would be a better choice for this job. Unfortunately, I haven't finished yet the modification I started some time ago.

Spectrum attached was extracted from 16x10sec stack, ISO400, taken by Canon 450D (FSM) through MTO 10_1100, all on EQ6 mount from my backyard in MtWaverley.