Monthly Archives: September 2016

Cygnus-Sadr Region – 2016-09-26

Friends of mine had a star registered with the name “MadVic” as a gift for their 60th wedding anniversary. So i decided to followup with an image of the region that showed the actual star.

Cygnus-Sadr Region - 2016-09-26

Cygnus-Sadr Region – 2016-09-26

The region around the centre of Cygnus is known as the “Gamma Cygni Nebula” (IC 1318); named after the bright star Gamma Cygni – Sadr. The nebula is a  large region filled with ionized hydrogen which shows up as the red background glow in the long exposure image above. The image is just a small section of the nebula. The bright stars also overwhelm the fainter background. The star Sadr in the lower right is particularly bright and it’s glow obscures the hydrogen cloud behind it.

Visually the region looks more like the image below. The star “MadVic” is marked with the green bars.

Cygnus-Sadr Region as it would look visual

Cygnus-Sadr Region as it would look visual

The star name was registered with the “International Star Registry” (ISR) as “MadVic”. While naming a star with the ISR isn’t quite the same thing as having the star name officially recognized by the “International Astronomical Union” (IAU), it is still fun.

ISR MadVic corresponds with official star catalog designations GSC 3160:00031 (Hubble Guide Star Catalog – GSC V1.2) and also USNO J2021000+412939 (the United States Naval Observatory – USNO-B1) . It is a magnitude 12.75 star in the constellation Cygnus at coordinates 20h 20m 59.95s D 41° 29′ 39.27″ (J2000). That’s about 1deg NW of the bright star Sadr at the centre of the cross in Cygnus.

The Constellation Cygnus

The Constellation Cygnus

While binoculars are great for finding constellations and large star clusters, MadVic is too faint to be seen even with binoculars. You can get a pretty good idea of where it is in the sky though.

MadVic Location in a 7x50 Binocular FoV

MadVic Location in a 7×50 Binocular FoV

A magnitude 12.75 star is just at the visual limit of a 4″ refractor even from a dark site.  The image below shows the view using a 4″ refractor with an 8mm eyepiece which translates to a magnification of 86x. The line of three stars just below “MadVic” will show up nicely and provide a guide to locating MadVic.

MadViv View using a 4" refractor and 8mm Eyepeice

MadViv View using a 4″ Refractor and 8mm Eyepeice

An 11′ scope would be better and then the star could be seen even from a moderately dark location. With a 8mm EP, the three “locator” stars are still in the field of view but much more obvious. MadVic is also easily identified as the corner star of a right angle triangle formed by three stars of similar magnitude.

MadVic using an 11" SCT and 8mm EyePiece

MadVic using an 11″ SCT and 8mm EyePiece

From a site with a limiting magnitude a little under 5, the 11″ SCT with 8mm eyepiece showed more or less the same stars indicated in the finder image above. The magnitude 12 stars were very faint though and at the limit of being visible. A darker site would make finding MadVic much easier.

MadVic sketch from the Eyepeice (redrawn to scale and flipped)

MadVic sketch from the Eyepiece (redrawn to scale and flipped)

The next two images show the precise location of MadVic. (Sorry, no fancy mouse overs.) Click on the next image to get the full sized version and then zoom in to see MadVic as photographed. The image at the bottom is a diagram highlighting the main objects in the camera field.

MadVic Locator in Image

MadVic Locator in Image

Cygnus-Sadr 2016-09-26 Annotations

Cygnus-Sadr 2016-09-26 Annotations