SH2-132

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Date
2019/07/26

Observation place
My permanent observatory in Longueuil
in white light pollution zone

Technical

TelescopeOrion 80ED refractor - Diameter 80mm, focal length 480mm, f / 6
MountCelestron CGEM
Imaging cameraAtik 383 L + monochrome regulated at -20o Celsius
Autoguiding cameraZWO ASI 120MM with one optical splitter
Auto Guidance Accuracy (RMS)1,05 '' arc RMS (2,10 '' arc total)
Image typeHa (Ha-OIII-OIII)
ExhibitionHa (10 x 10 'bin 2 × 2), OIII (10 x 10' Bin 2 × 2)
Image acquisition softwareMaxim DL
Guidance softwarePHD Guiding 2
PretreatmentMaxim DL
TreatmentPhotoshop and PixInsight

Object description

Object typeEmission nebula "The Lion Nebula"
ConstellationCepheus
Visual magnitudeunknown
Distance10400 light years
DiameterOver 250 light years
Dimension seen from Earthapprox.60 x 65 arc minutes, official data 30 x 20 arc minutes
Nebula SH2-132, called the Leo Nebula for its resemblance to this terrestrial animal, is an extended nebula in the constellation Cepheus. It is distant about 10400 light years from Earth and its diameter covers more than 250 light years. The stars responsible for the ionization of its gases are very hot and massive; in particular, two Wolf-Rayet stars have been identified, known under the letters HD 211564 and HD 211853. They emit their radiation mainly in hydrogen (Hydrogen-Alpha) and also very weakly in oxygen (OIII). The dark patches inside the nebula's head are caused by soot blocking light. There are also prominent dark nebulae that block starlight behind them outside the main area of ​​Sh2-132.

The Lion Nebula, due to the light signal practically absent in the light spectrum visible to the human eye, is very difficult to see visually, even in a large telescope and in a sky without light pollution. It is therefore observable especially in long exposure astrophotography. To see the nebula properly in the photos, it is imperative to use an H-Alpha luminance image which will bring out the hydrogen gases that make up most of the radiation from this nebula. Without the use of this filter, the nebula will remain inconspicuous and will be obstructed by the large number of stars that compose it. This H-Alpha filter also has the particularity of effectively combating light pollution.

Looking at my image and considering the very low luminosity of the SH2-132 nebula, it is still astonishing to have managed to get so much detail and depth in the luminosity of the nebula by photographing it from my site of extreme light pollution (white zone) which is located in Longueuil, a suburb of Montreal, Quebec, Canada. To take the entire SH2-132 nebula, do not rely on its official dimension seen from Earth which is 30 'x 20' of arc (a little smaller than the dimension of the Moon seen from Earth ). Its full dimension is approximately 60 'x 65' of arc, twice the size of the Moon! By taking it in full, we can see its resemblance to a lion, hence its nickname. Look at my picture, the lion's head is on the top left, its tail on the right, and its four paws below. Do you see it?
Richard Beauregard
Sky Astro - CCD
My impression "We cannot be alone in this gigantic universe"