open clusters – Page 33 – Astronomy Sketch of the Day

Phil’s Sax

The Alpha-Persei cluster caught my attention during a naked eye observation in
Austria. Melotte 20 is very large: 3°! The brightest star in the sketch is Mirphak
(Alpha Persei). I used the ETX 70 at the lowest power of 8.75. The FOV is 4.8°. A
total of 88 stars are captured. The limiting magnitude at that power is mag 9.5. A
higher power would reveal more stars, but then the cluster-look is lost. This
cluster also has a nickname : the Saxophone Cluster. Mel 20 is not a famous target.
But the view is very rewarding. I made a naked eye observation of Mel 20 last year,
so a powered view was the next logical step. Here is an observation of the cluster
at a power of 8.75 with the little ETX 70. Melotte 20 has also a Collinder number,
but I like the Melotte designation (patriotic feelings rise, due to the fact that
Philibert Jacques Melotte had Belgian parents )
(North is up, West is right)

Location : Bekkevoort, Belgium
Date: February 4, 2007 , 19.00UT
Seeing: 2 on a scale of 5, Transparency : 2
Scope : ETX 70
Eyepiece : TV 40mm

Rony De Laet

http://www.geocities.com/rodelaet, my personal website.

Sword of the hunter

One of the most majestic places to visit with a small scope or binocular might be
the sword of Orion. With every new magnification this fascinating complex of
clusters and nebulae shows more hidden treasures. So here is a 4° Fov impression of Orions Sword.

Place : Bekkevoort,
Date : Feb 21, 2007
Time : 21.00UT
Seeing : 3 (of 5)
Transp. : 2 (of 5)

Scope : ETX 70 with 26mm SP, no filter.
Power : 14x
Fov : 3,9°

North is up (bino orientation)

The sketch is digitally ‘drawn’ with Photopaint, based on a raw EP-sketch. I hope
you like it.
Rony De Laet

http://www.geocities.com/rodelaet, my personal website.

Glowing triangle

Observing M 103 requires a good deal of magnification, in binoculars or
at low powers, the cluster is only visible as a more or less bright
nebula or a small and distant group of stars. At higher powers, its
specific triangular shape becomes visible, three stars forming its
corners with two brighter stars in its center, one of them with a
striking reddish tone. Its catalog number is BD+59 274, a class M1Iab
star, a Red Supergiant. The double star at the cluster’s Northern-most
point is Struve 131.

Date: November 16, 2006
Location: Erbendorf, Bavaria, Germany
Instrument: Dobsonian 8″ f/6
Constellation: Cassiopeia
Seeing: II of VI
Transparency: II of VI
NELM: 5m0
Magnification: 200x

Sebastian Lehner

Diamonds at the feet of the twins

Open cluster M35 in the constellation Gemini

Here’s my first observation with the SkyWatcher 102/500. This 102mm rich field scope gives a whole new perspective on deep-sky objects. With a SP 26mm EP, I get a whopping 2.7 degrees field of view at a power of x19. I hope you like the view.

Date : March 8, 2007
Time : 20.30 UT
Seeing :2.5/5
Transp. 3/5

Digital sketch made with Photopaint, based on a raw pencil sketch made behind the EP.
N down, W left orientation.
Rony De Laet

http://www.geocities.com/rodelaet, my personal website.

Busy bees

Praesepe, Messier 44

Here is an encounter with an old friend, M44, visited with a new scope. The Skywatcher is a nice low power scope to enjoy large objects, like in this case : Praesepe. I tried to sketch the overall low power view, combined with the fainter stars visible at 33x. The higher power allowed me to separate ADS 6921 (in the Northern arm of the V shape) into four components : mag 6.4,7.6,9.2,10.4. You might need to squeeze your eyes to notice the fourth star in the sketch. When the sketch was finished, I counted (just for fun) the numbers of stars I’ve drawn. The number is 147.

Rony De Laet
http://www.geocities.com/rodelaet, my personal website.

Date : March 14, 2007
Time : 21.30UT
Scope : Skywatcher 102/500
Eyepieces : TV SP 40mm, SP 25 mm, SP 15 mm
Power : 12.5x to 33x
FOV: 3.3°
Filter : none
Seeing : 2.5/5
Transp. : 2/5
Sketch Orientation : N down, W left.
Digital sketch made with PhotoPaint, based on a raw pencil sketch.

Resplendent raptor

M16 Eagle nebula

This nebula was drawn with graphite pencils on
white paper and then inversed after scanning.
The main field stars (until about magnitude 11)
was printed with a charting software and the
fainter stars and nebula were added during the
observation. It took about an hour to lay all the
details on paper.

17.5-inch dobsonian, F/4.5, 74 &125x, OIII filter
used for the fainter parts; 15/august/2004,
22h00UT, good transparency (visual limit of 6.31
in UMi); from La Clapière in the french alps at
an elevation of 1650m.

Yann Pothier

A rose by any other name

The Rossette nebula, NGC 2237-8, 46

Here is a challenging object. It was at the threshold of visibility for me and my gear. The nebulae was visible at a power of 12.5 (40mm EP) and at 19x (26mm EP). It vanished at any higher power!! The sketch was made with help of a lumicon UHC filter. But the most significant aid in detecting the ghostly glow was wobbling the scope left and right. The eye is more sensitive to moving ghosts than to steady
ones. As a result of the UHC filter, the fainter stars are lost. But I wanted to concentrate on the nebulae. The sketch was made in Photo-Paint, based on a raw pencil-sketch behind the scope. I hope you like the view.

Rony De Laet

Sketch data:

Date : March 9, 2007
Time : 21.00UT
Scope : Skywatcher 102/500
EP : 26mm SP
Power : 19x
FOV: 2.7°
Filter : Lumicon UHC
Seeing : 3/5
Transp. : 2.5/5
Sketch Orientation : N down, W left.