Archive for the ‘Observer’s Challenge Reports’ category

M41- Open Cluster in Canis Major-February 2018 Observer’s Challenge Report #108

March 9, 2018


Pencil sketch:  6-inch reflector @ 46x and 1.3º field of view: 

M41 Adjusted

Inverted colors

Rogers M-041 Inverted

Messier 41 (NGC 2287) at magnitude 4.5 is visible without optical aid. I often enjoy viewing this cluster with a pair of 7 x 21 mini-binoculars. It is easily located at about 4º south of Sirius, and NW of 6.0 magnitude 12 Canis Majoris.

A beautiful, but sparse cluster, very irregular shape, with several small chains of stars. The most noticeable star chains are on the SW and NE.

When using a 6-inch reflector, I can count ~60-70 stars. A small circlet of stars envelope the central region of the cluster. M41 contains the famous red star, known as the Espin star (HD 49091) magnitude of 6.9 and a K3 spectrum. The star was named after Rev. T.E. Espin (1858-1934.) I normally see this star as a deep-orange in color.    Roger Ivester


M41 image by James Dire:  

102mm (4-inch) f/7.9 refractor using a 0.8X focal reducer field flattener with an SBIG ST-2000XCM CCD camera. The exposure was 30 minutes. North is up, and east to the left.


M41 is a beautiful galactic star cluster located 4° south of the bright star Sirius. The cluster can be seen naked eye from a dark site. It’s mag. 4.5 and is 39 arcminutes in diameter. It lies 2,350 light-years away

Aristotle noted M41 in 325BC as being a cloudy patch in the sky. The cluster was first cataloged by the Italian astronomer Giovanni Batista Hodierna in 1654, and then John Flamsteed in 1702. Charles Messier added it to his catalog in 1765.

M41 has about 100 stars. The brightest is a mag. 6.9 red giant star near the apparent center of the cluster, cataloged as HD49091. This K3 star has the brightness of 700 suns. The cluster is estimated to be 190 to 240 million years old and has a chemical composition similar to the sun.

The brightest star in the image is near the bottom edge, left of center. That star is 12 Canis Majoris, or HK Canis Majoris. HK is a mag. 6 blue giant star with a surface temperature of 18,000K. HK is only half the distance of M41 and thus is not a member of the cluster. The next brightest star in the image is the red giant HD49091, the red giant star near the center of the cluster.   James Dire 



Planetary Nebula IC 418 in Lepus: February 2019 Observer’s Challenge Object.

February 14, 2018

Planetary Nebula IC 418, Lepus, magnitudes; nebula 9.3; central star 10.3

IC 418, also known as Spirograph Nebula.  The name derives from the intricate pattern of the nebula, which resembles a pattern which can be created using the Spirograph, a toy that produces geometric patterns (specifically, hypotrochoids and epitrochoids) on paper.  Source “wikipedia”

The following image:  Hubble Space Telescope


I had a telephone conversation with Glenn Chaple yesterday.  Glenn mentioned PN IC 418 as a potential object for the 2019 observer’s challenge report. This planetary had been suggested by Joseph Rothchild at the most recent meeting of the (ATMoB) Amateur Telescope Makers of Boston. Richard Nugent also of Massachusetts sent me an email, saying he had recently observed this very interesting planetary, using a 20-inch reflector.  

It was only after checking my notes “this morning” (February 14th 2018) did I realize I had also observed this planetary…..25 years ago on (February 14th 1993) which is very coincidental.  

My notes (verbatim) from February 14th 1993:  

10-inch reflector: ” Looks like a blurred star. I would focus on stars outside the telescope field and then sweep back. The nebula was very apparent and obvious when using this method. Nebula fairly bright, mostly round and featureless.  Bluish in color and very small.  No nebula filter was used.”     

Skiff & Luginbuhl:  “This planetary is clearly visible in a 6 cm, appearing as an undistinguished mag. 9 star.  In 15 cm the central star becomes visible, while 25 cm shows it clearly at 200 x.  The surrounding nebula has a high surface brightness, making a poor contrast for the central star.”

This will be the February 2019 observer’s challenge object.   RI 

NGC 1624 – Cluster (+) Nebula Perseus – January 2018 – Observer’s Challenge Report

January 12, 2018

Complete Observer’s Challenge Report:  Click on the following link.


Pencil sketch using a 5 x 8 note card with the colors inverted:  10-inch reflector at 200x.  Roger Ivester

Rogers NGC-1624 Inverted

Image by James Dire from Hawaii


Image by Mario Motta from Massachusetts using a 32-inch telescope


NGC 925 – Galaxy – Triangulum December 2017 Observer’s Challenge Report #106

January 11, 2018

Click on the following link for the complete Las Vegas Astronomical Society, Observer’s Challenge report: 


Pencil Sketch:

Rogers NGC-0925 Inverted

Photo by Mario Motta from Massachusetts:  32-inch telescope 



NGC 772 – Galaxy In Aries – November 2017 Observer’s Challenge Report #105

December 1, 2017

LVAS Observer’s Challenge:  Click on the following link. 


NGC 772, faint mag. 12 galaxy in Aries 

10-inch reflector at 104x, NGC 772 is faint, difficult with low surface brightness, elongated, but subtle, oriented NW-SE.  The middle is a bit brighter with little concentration.  A pin-point stellar nucleus was noted, however intermittently, and required averted version.  Very soft mostly even halo with the edges fading gradually outwards.  My observing location was from my my 5.0 NELM backyard.  

The last time I observed this galaxy was November 1993, from the same location and telescope.  My notes from that session were almost verbatim to my most recent observation.  A true dark site is necessary to see faint details and structure, especially when using a 10-inch telescope.    Roger Ivester

Pencil sketch 10-inch reflector with a 5.0 NELM


Image and notes by James Dire from Hawaii using a 10-inch Newtonian Reflector


Image by Mario Motta:  32-inch Telescope 



M15 Globular Cluster – Pegasus October 2017 – Observer’s Challenge Report

November 14, 2017

October 2017 Observer’s Challenge:  Click on the following link for full report. 


Easy to see in 7 x 50 finder.  10-inch reflector at 267x, M15 appears mostly round with a bright intense middle, and an excellent resolve of stars in the outer regions.  When using averted vision, an intermittent sprinkling of faint pin-point stars in the central region.  An impression of dark lanes extending outward from the core and a star chain around the SSW edge.  Bright field star to the north.

3.5-inch Maksutov, M15 appears circular with a very bright and intense center.  There is no resolution of stars with this aperture.  RI 

Pencil sketch 10-inch reflector at 267x 



Image of M15 by James Dire from Hawaii using an 8-inch f/8 RC telescope  

James M-015-2


M15 photo by Mario Motta of Massachusetts using a 32-inch telescope. 


NGC 6905 – Planetary Nebula – Delphinus – Observer’s Challenge Report – September 2017

October 11, 2017


Pencil sketch using a blank 5 x 8 note card with the colors inverted. 

Rogers NGC-6905