Archive for January 2, 2021

IC 348 – Open Star Cluster Plus Nebula – Perseus – January 2021 Observer’s Challenge Report #144

January 2, 2021

Compiled by:

Roger Ivester, North Carolina 


Sue French, New York

January 2021

Report #144

IC 348 – Cluster plus Nebula in Perseus

Sharing Observations and Bringing Amateur Astronomers Together

This month’s target

During his term as the first director of Dearborn Observatory, Truman Henry Safford discovered IC 348 on December 1, 1866, with the observatory’s 18.5-inch refractor. Safford published his observation in a table of objects found at Dearborn in the years 1866–1868. The table uses the alphabet-soup notation common to the era, which decrypted means: very large, very gradually brighter in the middle, pretty bright. Additionally, a note below that section of the table describes the object as “A loose cluster with nebula.” The combo appeared in the First Index Catalogue.

IC 348 has the dubious honor of bearing two IC designations. Edward Emerson Barnard independently discovered the nebula in 1893, and it was placed in the Second Index Calalogue as IC 1985, without anyone tumbling to the fact that it was already in the previous IC catalog. Unlike Safford, Barnard didn’t note the existence of the cluster within the nebula. 

IC 348 is thought to be roughly 1000 light-years away and a youthful 2–3 million years old. It holds about 500 stars, with brightest being hot, blue-white stars on the main sequence. The cluster’s visual magnitude is 7.3. By Sue French

Sue French: Observer from New York

Through my 105-mm refractor at 153×, the little star cluster IC 348 shows 10 stars mostly gathered into a 5′ oval ring. If I keep Omicron (ο) Persei out of the field, I can faintly see nebulosity enveloping the brightest star and the two stars closest to it. A third star sits on the nebula’s western edge. The brightest star (magnitude 8.8) and the one to its northeast (magnitude 10.3) form the visible Σ439 AB-C pair. The A and B components are only 0.6″ apart, which is too snug for my little refractor to split. Σ437 sits a short distance west-southwest of the oval ring in the same field of view, its stars closely matched at magnitudes 9.8 and 10.0. 

Through my 10-inch reflector at 115×, the blended AB component of Σ439 looks white, and its wide companion appears yellow. The stars of Σ437 seem white and pale yellow to my eyes. The brightest and largest piece of nebulosity is visible around Σ439 and a small, dimmer patch cocoons the southernmost star in the cluster. Very faint nebulosity envelopes and connects these patches, extending farther east than west.

Mario Motta: Observer from Massachusetts

This is 90 min, about 30 mins each Red/green/blue through the 32-inch scope, asi6200 camerainteresting in that I thought was mostly a reflection nebula, but the nebula is both red and some blue, so must be both reflection and some emission.

I intentionally put bright star Omicron, to the north, just out of the field to prevent it from overwhelming the image. That star is very blue and bright, and it must be ionizing some of the nebula.

Click on photos, images and sketches to enlarge:

Roger Ivester: Observer from North Carolina

IC 348, open cluster in Perseus enveloped with nebulosity:  

Just to the south of bright star Omicron Persei (apparent visual magnitude 3.8) lies the sparse and scattered open cluster IC 348, which contains about 10 mostly dim stars.   

When using my 10-inch reflector at a magnification of 114x with averted vision, and much patience and field motion (lightly tapping the telescope) I could see some faint nebulosity surrounding areas of the cluster.  This effort required over an hour of careful observing to finally see sections of the nebula.  

It’s was necessary to move Omicron out of the field to see the nebulous areas within the cluster.  

The nebulosity was extremely difficult with the most concentrated area being in the NE region, surrounding the wide and uneven double star, Struve 439.  This double is actually a triple, but the third component is far too close for most back yard telescopes.   

Another double, Struve 437 is a beautiful equal pair of white magnitude 10 stars located on the SW edge of the cluster. 

 Glenn Chaple: Observer from Massachusetts

IC 348 is a star-forming region in Perseus, located just 7 arc-minutes south and slightly east of the magnitude 3.8 star omicron (ο) Persei. It contains several hundred stars, most of which are too faint to be seen with typical backyard scopes. The cluster illuminates the surrounding reflection nebula VdB 19. Visually, a small-aperture scope will capture a dozen or so of the brighter cluster members, while the nebulosity mandates medium to large apertures and a dark-sky location.  

In her book Deep-Sky Wonders, Sue French mentions a triple star, Σ439, and a double star, Σ437, that are associated with IC 348. In most scopes, Σ439 appears as a magnitude 8.8 and 10,3 double separated by 23.4”. The brighter star is actually a tight binary system (BD+31°643) whose magnitude 9.3 and 9.5 components, both hot B5-type main sequence stars, are just 0.6” apart. Σ437 is a near twin system comprised of magnitude 9.8 and 10.0 stars separated by 11.4”.

IC 348 is a young open cluster, perhaps no more than 2 million years old. Cluster and nebula are 900 to 1000 light years away.

Uwe Glahn: Observer from Germany

IC 348

27-inch reflector @ 172x

NGC 1893, IC 405, IC 410

20 x 125 Binoculars

3º Field of View

IC 410 (NGC 1893)

27-inch reflector @ 172x

Larry McHenry: Observer from Pittsburgh, Pennsylvania

January:  IC 348 – Cluster & Reflection Nebula – Perseus; Mag. V=7.3;  Size 8′ 

RA:  03h 45m  Dec.  +32° 10′  

IC 348 is located in the fall constellation of Perseus – ‘The Hero” near +3.8 mag Omicron Persei (Atik).

This 7th magnitude deep-sky object is a sparse open star cluster embedded in a faint reflection nebula cataloged as Vdb19. The nebula is difficult to observe visually due to the nearby bright star. The star cluster, also known as Collinder 41, contains around 12 stars visible to amateur astronomers, but has close to 288 stars in total with over 20 identified as brown dwarfs.  It is about 1,028 light years distant, and about 2 million years old. 

Video-Capture:  10/08/2010 from rural location near Mansfield, OH at the Hidden-Hollow star party, using an 8-inch SCT optical tube @ f/6.3 on a CG-5 mount, using a StellaCam-3 analog video-camera @ 45 seconds, unguided single exposure.

The visual screen sketch as following was made in January 2021 from Big Woodchuck Observatory, backyard in Pittsburgh, PA.

Using an 8-inch SCT optical tube @ f/6.3 on a Atlas HQ6 mount, with a ASI294MC color camera and L-Pro filter @ 30-second guided exposure live-stacked for 2 minutes.

Barry Yomtov: Observer from Massachusetts

Here is my most recent image of IC 348. I am located in Marblehead, MA. The transparency started off ok (Jan 10, 2021), but deteriorated about two-thirds though my imaging session so I was able to only use 71 images. My equipment is the RASA 11 (f/2.2) with the Astrodon light pollution filter, and the ZWO ASI-183MC Pro CMOS camera. The total exposure was 41 minutes.