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View Full Version : Object of the Week October 11, 2020 - The Wizard



deepskytraveler
October 13th, 2020, 02:07 AM
Sharpless 142, Sh2-142, LBN 511
Constellation: Cepheus
Type: Diffuse Emission Nebula
RA: 22h 47.5m
DEC: -58° 03'
Size: 35.0’ x 18.5’

NGC 7380, Cr 452, Lund 1022, OCl 244, Mrk 48
Constellation: Cepheus
Type: Open Cluster
RA: 22h 47.3m
DEC: -58° 08'
Mag: 7.2
Size: 20’

Tucked away in the southeastern corner of the constellation Cepheus are this week’s Object of the Week pair, NGC 7380 and The Wizard. The open cluster, NGC 7380, was discovered by Caroline Herschel on August 7, 1787 on the occasion of being free from recording duties when her brother William was absent preparing for his marriage. To Caroline NGC 7380 was merely a coarsely scattered cluster of stars. She did not detect the faint nebulosity which engulfs the star cluster.

This nebulosity is The Wizard, commonly known as the Wizard Nebula, an emission nebula (HII) that surrounds the open cluster. Cataloged as Sharpless 142 or Sh2-142 for short, the name comes from a catalog of 312 emission nebulae compiled by Steward Sharpless. The first edition was published in 1953 with 142 objects (Sh1) and the second and final edition was published in 1959 with 312 objects (Sh2). Sh2-142 is a portion of the extensive Cepheus ΟB1 Association (http://galaxymap.org/drupal/node/106), an “old” star-forming region that extends some 2,000 light years wide. NGC 7380 has 125 members of 9th magnitude and fainter. Most are Type Ο and early Β stars that are still embedded in their natal cocoons of dust and gas. The nebula is ionized by the eclipsing binary star DH Cephei (HD215835), together with the many young energetic stars within the cluster.

4037
Image Credit & Copyright: Dean Jacobsen (www.astrobin.com/users/deanjacobsen (https://www.astrobin.com/users/deanjacobsen/))

NGC 7380 is a fairly easy object for amateur telescopes under moderately dark skies. However despite being fairly large, the Wizard Nebula is a challenging object to observe and requires an OIII filter and extremely clear, dark skies. But It can be seen in a small telescope. Visually, the nebula’s size is comparable to that of the Moon.

Sue French in Deep-Sky Wonders notes the following. “The cluster has a hazy background, but am I seeing unresolved stars or nebulosity? At 28x [105mm refractor] a green oxygen III filter seems to slightly enhance and extend the haziness with an unfiltered view.”

Christian Luginbuhl and Brian Skiff share their observations in the Observing Handbook and Catalogue of Deep-Sky Objects. “Though this cluster is involved with a faint nebulosity, none is easily discernable visually in amateur instruments. 15 cm shows the cluster nestled in a circlet of bright stars. It is 10’ diameter with 20 stars resolved over haze. About 40 stars are visible in 25 cm, including a distinctive V-shaped asterism pointing N. The brightest star (V=8.6) is on the SW at one end of the V. 30 cm reveals about 30 stars, including a bright pair about 10’ to the W (ADS 16260: V=7.6, 8.6; 31”; 117°).”

So why is Sharpless 142 commonly known as the Wizard Nebula? Visually, the interplay of stars, gas, and dust has created a shape that appears to some like a fictional medieval sorcerer. Perusing some of the many photos of the nebula I was unable to make the connection at first, until I came across this incredibly striking photo by J-P Metsävainio.

4036

Image Credit & Copyright: J-P Metsävainio (http://astroanarchy.zenfolio.com)
This image was created in HST-palette (HST=Hubble Space Telescope) from the emission of ionized elements, R=Sulfur, G=Hydrogen and B=Oxygen.


"Fillet of a fenny snake,
In the cauldron boil and bake;
Eye of newt and toe of frog,
Wool of bat and tongue of dog,
Adder's fork and blind-worm's sting,
Lizard's leg and owlet's wing,
For a charm of powerful trouble,
Like a hell-broth boil and bubble.

Double, double toil and trouble;
Fire burn and cauldron bubble."
--William Shakespeare, Macbeth (IV.i.12-21)


Happy Halloween!

Now it is your turn. Give it a go and let us know!

j.gardavsky
October 13th, 2020, 07:12 PM
Hello Mark,

a very nice choice, both on the appearance of the Wizard Nebula, and on its astrophysics!

The Wizard Nebula is on the south-eastern arc of the Cepheus Bubble, and visually, the second brightest object of the Cepheus Bubble nebulae.

The OIII filters reveal a condensed glow due to the collisional ionization, the HII glow is ionized by the binary DH Cephei.
The most impressive views have been through my favourite blue(RGB)CCD filter, revealing through the 6" F/5 achro a sort of "boomerang" form.
Other filters I have had on the filter wheel, have been the UHC and H-Beta.

I have seen this nebula through all my binoculars from 7x42 up to 25x100, with and without filters, and of course through my 6" F/5 achro. The total number of the entries in my observing logbook is 89, last entry of September 19th, 2020.

This is really a very nice nebula with an open cluster,
Jiri

Uwe Glahn
October 16th, 2020, 05:25 PM
I needed a long time to make peace with the "Wizard".

Starting 19 years ago with my former 20x125 binocular I suspected a large, bright nebula but saw something different. I wrote: OC stands out nicely in front of the interesting background; small and bright nebula which surrounded OC in a triangle shape, fainter nebula suspected east and west from the OC; King 18 0,5° east; beside King 18, three other nice star patterns surrounded OC

sketch: 20x125, 3° field, NELM 6m0+
4038
home (http://www.deepsky-visuell.de/Zeichnungen/NGC7380.htm)

So, in overall, no spectacular nebula. Beside the nice star field a disappointing observation.

Later I revisited the nebula several times with different apertures. Starting from the smallest aperture I wrote.

4" binocular, 55x, [OIII], NELM 6m5+
bright nebula even without filter in the central 10' region around the OC; [OIII] brings out some more nebula but darken the field immensely; second brightest part runs to the south around 10' long; faintest part to the north with also around 10' length

16", 51x, UHC, NELM 6m5+
very nice object for lower magnification; field dominated by the large, round OC; nebula started a little offset to the east and runs around 0,5° to the southwest

27", 113x, [OIII]/Hß, NELM 6m0+
loose OC, which forms a triangle; without filter a brightening at the W tip of the OC is visible; with [OIII] the center of the OC shining much brighter and shows a fainter bend brightening 20' to the south; Hß brings out another fainter glow to the east

27", 113x, [OIII], NELM 6m5+
large, bright and rich star field; even with poor seeing a detailed observation with [OIII] showed a very structured nebula with some dark structures within the center and fainter parts in every direction; Hß shows other parts but gave an overall less spectacular and darker appearance

sketch: 27", 113x, [OIII], NELM 6m5+
4039
home (http://www.deepsky-visuell.de/Zeichnungen/NGC7380_27.htm)

wvreeven
October 16th, 2020, 05:30 PM
Incredible observations. I visited the region once with my 20" and noted only the open cluster, which I described as resembling the Hyades. I didn't use any filter so no wonder that I didn't see the nebula. I will have to revisit this region at some point which will be hard with my 20" currently being located in Chile...

Steve Gottlieb
October 17th, 2020, 10:39 PM
This observation is from 21 years ago, so I'm about due for another look!

Using 100x (with both an OIII and UHC filter) a bright triangular-shaped nebulosity (Sh 2-142) of 8'-10' diameter is superimposed on a rich cluster of stars (NGC 7380). All within a rich Milky Way field. A wide strip of nebulosity is attached near the southeast vertex and extends to the southwest. A dark band appears to separate this strip from the triangular patch. The surrounding region appears weakly nebulous and the "edge" can be traced with some certainty further the north. The brightest star is mag 8.5 DH Cep at the west vertex of the cluster. This star is a very rare spectroscopic eclipsing pair of massive O5.5/O6.5-type stars and the main ionizing source.

Raul Leon
October 21st, 2020, 08:46 PM
Hi, here's my observation from 10/17/2020: Ngc 7380 is a combination open cluster with a nebula. Mag:7.2 ; size: 35'x18.5' ; open cluster dims when OIII filter is on, but the nebulosity becomes more apparent. The nebulosity is triangular shaped and has a dark lane separating some of the nebulosity. I used a 21mm Ethos at 75x with a Lumicon OIII filter with my 14.5 Starstructure Dob f/4.34050