Yesterday the sky cleared after raining for a large part of the day. Rhys and I tried to take a spectrum of the Ring Nebula M57 using a new combined flip mirror/off axis guider/hand-guided on Manfrotto video mount. Unfortunately, the experience showed clearly that these nebulae are very faint and we will need to use GOTO power-driven mount to keep the object on the spectroscopy slip whilst taking spectra of these objects.
We did obtain a spectrum of Vega (for calibration), a spectrum of Arcturus and for the first time a spectrum of Sadr.
Sky Watcher Equinox Pro 80mm OTA, with finder scope with illuminated eyepiece, Teleskop Express combined flip mirror/off axis guider and astrometric eyepiece, CCDSPEC with Meade XY adjustable illuminated eyepiece. The experience last night indicated another XY adjustable illuminated eyepiece would be a better choice to the astrometric eyepiece on the combined flip mirror/off axis guider and in fact a flip mirror might be a better choice to the combined flip mirror/off axis guider as will direct more light to the eyepiece (below):
Calibrating spectrum of Vega (using know Vega lines):
Calibration information on Vega lines I have determined previously (see https://roslistonastronomy.uk/re-analysis-of-vega-spectrum-from-4-8-2018):
Vega from 8/6/2019:
Arcturus (spectral class K1.5IIIFe-0.5):
With an apparent visual magnitude of 2.23, Gamma Cygni is among the brighter stars visible in the night sky. The stellar classification of this star is F8 Iab, indicating that it has reached the supergiant stage of its stellar evolution.
We initially guided to Sadr using green lazer on finder show – carefully aligned so point of lazer coincided with CCDSPEC slit – this meant that we did not need to use illuminator on eyepiece – the green lazer was sufficient to show up the guiding reticule on the illuminated eyepiece and a lot fainter than the red light on that eyepiece – we demonstrated that this is an effective method for guiding to fainter stars.
Sadr – this time spectrum without using green lazer: