Spectrum: Comet ISON

The spectrum below of the comet ISON shows how easy it is for amateurs to study astronomical spectra. This wonderful spectrum of ISON using a just an 80 mm refractor, simple Star Analyser grating, and a DSLR. It clearly shows the green glow from glowing Carbon (the so-called “Swan bands” – Wikipedia link) This image was captured from a rooftop in Rajasthan, and then processed in the RSpec software.

Comet C/2013 X1 PanSTARRS

We carried out the spectroscopy of Comet C/2013 X1 PanSTARRS (Vmag = +9.67) as on 2016.01.09, using LHIRES-III spectrograph (23µm long slit, R=700, Angstrom /Pixel (A/P) =3.0) fixed on 0.20m SCT. The spectral image captured using Atik460ex cooled monochrome CCD coupled with LHIRES-III spectrograph. The image guided over spectrograph slit using Atik 383L+ monochrome CCD to get better S/N ratio. Comet seems enriched with C2,C2,CH+ & CN.
The spectral data corrected for instrument response and normalized. We used following software for different purposes.
APT Tool: LHIRES guiding/Histogram/Capture
Telescope control: Starry Night pro7 + EQMOD
CCDstack2.0: Image calibration
RSpec: Spectroscopy
Cepheids Astronomy Group, RBT, India.

Comet C/2013 US10 Catalina

We carried out the spectroscopy of comet C/2013 US10 Catalina (Vmag = +6.1) as on 20th December-2015, using LHIRES-III spectrograph (23µm long slit, R=700, Angstrom /Pixel (A/P) =3.0) fixed on 0.20m SCT. The spectral image captured using Atik460ex cooled monochrome CCD coupled with LHIRES-III spectrograph. The image guided over spectrograph slit using Atik 383L+ monochrome CCD to get better S/N ratio. Comet seems enriched with C2,C2,CH+,CO+ & CN.
The spectral data corrected for instrument response and normalized. We used following software for different purposes.
APT Tool: LHIRES guiding/Histogram/Capture
Telescope control: Starry Night pro7 + EQMOD
CCDstack2.0: Image calibration
RSpec: Spectroscopy
Cepheids Astronomy Group, RBT, India.

Nebular Spectroscopy and extinction

After posting result related to Nebular Density Ratio of M42 “Orion Nebula” The results for Nebular Density Ratio without Interstellar Redding correction were c(Hb) = 0.0:
Ha/Hb = 5.17
Hy/Hb = 0.35
OIII5007/OIII4959 = 3.0
We have corrected data for interstellar extinction using formula:
c(Hb)= 3.08Xlog(I(Ha)-7.55, Ic=IoX10^(c*f).
We found c(Hb) equal to 0.81. In continuation, the paper said the IS extinction in between 0.0 to 1.6 for M42, but most of the places it is near to value 0.8.
The results for Nebular Density Ratio with Interstellar Redding correction c(Hb) = 0.81:
Ha/Hb = 2.79
Hy/Hb = 0.49
OIII5007/OIII4959 = 2.92
See paper link https://iopscience.iop.org/article/10.1086/301429/fulltext/
The corrected data are shown by dotted points:
If We follow paper given in link https://www.aanda.org/…/2011/01/aa14464-10/aa14464-10.html
and use IS extinction formula given by then
The results for Nebular Density Ratio with Interstellar Redding correction c(Hb) = 0.73:
Ha/Hb = 2.97
Hy/Hb = 0.48
OIII5007/OIII4959 = 2.93
Doing this exercise We guess, the slit was exposed in a place where IS extinction was in between 0.81 to 0.73.