Archive for November 2019

IC 1805 – “Cluster + Nebula” In Cassiopeia – December 2019 – Observer’s Challenge Report #131

November 23, 2019

 

MONTHLY OBSERVER’S CHALLENGE

DECEMBER 2019

Report #131

IC 1805 Open Cluster in Cassiopeia

Observer’s Challenge Report Final:  Click on the following link

DECEMBER 2019 OBSERVERS CHALLENGE – IC-1805

 

Note:  The following are mostly original notes, with very little if any editing, to preserve the feelings and thoughts of the observer during the observation.  This is not the “official” Observer’s Challenge report, but what I call a “work-file” just to organize the entries.  Roger Ivester

     IC 1805 is a 6.5-magnitude cluster about 62 stars that spans about 20 arcminutes. It’s nearly centered on the group’s brightest member, HIP 11832 shining at magnitude 7.1. The cluster is young at only 2.5-million years and we see it at a distance of roughly 6,500 light-years. IC 1805 is enveloped in and associated with the emission nebula Sharpless 2-190, commonly called the Heart Nebula, which sprawls across 1.6 º of sky.

     Edward Emerson Barnard discovered IC 1805 photographically and included it on the first two plates of his wonderful Photographic Atlas of Selected Regions of the Milky Way.  The atlas can be viewed online at:

https://exhibit-archive.library.gatech.edu/barnard/     Intro by Sue French  

 

IC 1805, December 2019, Observing Report by Mario Motta: 

Color Image:  This was combined with 1 hour each of Oxygen 2 filter and Sulfur filter:  See attached.

IC 1805 (the Heart Nebula), North is to the right on this image, rotated to show the “heart” shape more readily.

Of course…to a cardiologist the Right heart (on the left, person facing you), is very “enlarged” so this is a rather sick heart, with what I would call right heart failure.    Mario Motta 

 

 

IC1805

 

Sue French: Observer from New York:

14×70 binoculars:

IC 1805 is a fairly large, loose open cluster of six to eight moderately bright stars, depending on the borders, plus about 15 more stars on the backdrop.

105/610mm (4.1-inch f/5.8) refractor

     17×: Nebulosity is faintly visible without a filter, a little better with a UHC filter, and very nice with an O III filter. The brightest areas include: the IC 1805 cluster; a wide arc that runs between clusters IC 1805 and NGC 1027 and then loops around north of the IC 1805 cluster; and a small patch in the position of the nebula complex NGC 896/IC 1795. A fainter arc starts between the two clusters, loops around south of cluster IC 1805 and then northward on the western side of this cluster.  Both loops are quite patchy with very uneven brightness. Nebulosity also stretches from cluster IC 1805 to the eastern loop.

     87×: About 40 stars are visible in cluster IC 1805. Its brightest member is a double star, residing in a rough circlet of fainter suns at the cluster’s heart. Arms of stars starting north and south of the circlet curve westward. Two fairly bright stars northeast form a faint star with the lucida.  A broad scattering of stars straggle east through southeast from the circlet, while extremely faint specks of light can be seen within the circlet and rounding out the group.

     The double star is Stein 368 AB (STI 368 AB), PA 97º, separation 9.9″, component magnitudes 8.0 and 10.1. NGC 1027 displays about 50 stars centered on the group’s central lucida. Starting north-northwest of the star, its brightest attendants spiral outward from it for about 1½ turns.

     These observations were made in the northern Adirondack Mountains of New York, where my naked-eye limiting magnitude near Polaris was 6.3.

 

Roger Ivester:  Observer From North Carolina 

     In November I used a 6-inch f/6 reflector in an attempt to see the nebula in IC 1805. My eyepiece of choice for this night was a 2-inch-barrel 26mm with an O III filter. This gave me a field of view of 2º. 

     Scanning the area before using the O III filter, I first saw open cluster NGC 1027. A bright cluster at magnitude 6.7, consisting of about 20 stars with one brighter member located in the center. This cluster is located just to the east of IC 1805. 

     Now to IC 1805: I could easily see the cluster of stars located in the central region of the IC 1805 nebula. When adding an O III filter, I scanned the area for more than an hour; however, I cannot say definitively that I could see any nebulosity.

     On December 15, 2019, I used an 80mm f/5 refractor, with a 24mm eyepiece and a UHC filter. I was a bit dubious before beginning my observation that I’d be able to see the IC 1805 nebula based on my results using a 6-inch reflector only a month earlier, and with similar sky conditions. 

     After about thirty minutes, I could not see any of the nebula, but the central stars were easy and bright. However, when I began using my “manual” slow-motion controls, I began scanning across the IC 1805 area, and to my surprise, I began seeing very faint brightenings in the area. I scanned one section at a time, and was able to sketch extremely faint tentacles and fingers of nebulosity, only marginally brighter than the background. After more than two hours of “slow-motion” scans, well over two hundred crossings, I was able to sketch some of the brighter sections, encircling the central cluster. 

Telescope: 80mm f/5 achromatic refractor 

Eyepiece: 24mm + UHC filter 

Sketch Magnification: 17× 

Field of View: ~3.5º 

Roger IC 1805

 

James Dire:  Observer From Illinois 

     The Heart Nebula, IC 1805, is part of a vast complex of nebulae located in the constellation Cassiopeia. The nebula is located five degrees southeast of the star Segin and eight degrees east of the star Ruchbah. Segin and Ruchbah are the two easternmost stars making up Cassiopeia’s “W” asterism. 

     The brightest part of the Heart Nebula is separately known as NGC 896. NGC 896 was discovered by William Herschel in 1787 using his 18.7-inch reflector. NGC 896 measures 27 x 13 arcminutes and is estimated to be magnitude 10.

     The Heart Nebula itself extends about one degree in both right ascension and declination. The Heart Nebula lies 7500 light years away in the Perseus arm of the Milky Way Galaxy.

     IC 1805 is also the designation of an open star cluster in the middle of the Heart Nebula. This cluster is also known as Melotte 15. This loose open cluster is estimated to be a mere 1.5 million years old and contains several bright stars 50 times the Sun’s mass. These stars are responsible for exciting the hydrogen gas in the Heart Nebula resulting in the red glow as seen in photographs.

     My image of IC 1805 was taken with a 71 mm f/4.9 apochromatic refractor using an SBIG STF-8300C CCD Camera. The exposure was 140 minutes. In the image north is up and east to the left.

     The second image has labels pointing out the location of NGC 896 and the central star cluster in IC 1805. Two more open clusters are labeled in the image. The first is NGC 1027 located on the east side of the heart. NGC 1027 is a bright rich cluster of approximately 50 stars all within a 20 arcminute circle. The cluster has a total magnitude of 6.7. The other cluster is called Markarian 6 and is located southwest of the heart. Markarian 6 is magnitude 7.1 and is 6 arcminutes in diameter. All three star clusters contained in the nebula are worthy of inspection with any telescope at medium to high powers.

     My best view of the Heart Nebula was with my 14-inch f/6 Dob using a 26mm eyepiece (82x). This combination provides a one-degree true field of view. While the view comes nowhere close to my image, it was possible to see many of the brighter regions of the nebula, especially NGC 896 and the three above-mentioned star clusters.    

fullsizeoutput_122f

fullsizeoutput_1230

 

NGC 246 – Planetary Nebula – Cetus November 2019, Observer’s Challenge Object

November 22, 2019

NOVEMBER 2019 OBSERVERS CHALLENGE – NGC-246

 

 

NGC 7448 – Galaxy in Pegasus – Observer’s Challenge Object – October 2019

November 9, 2019

The complete Observer’s Challenge report link as following: 

OCTOBER 2019 OBSERVERS CHALLENGE – NGC-7448_

My first observation of galaxy NGC 7448, came on the night of October 24, 1994, using a 10-inch reflector.   Roger Ivester 

October 24th 1994: 

“10-inch @ 57x, can vaguely detect with direct vision, situated between two two dim stars, which are oriented ESE-NW of the galaxy.  When increasing the magnification to 190x, the galaxy appeared elongated, still fairly difficult, but could be seen with direct vision.  However, averted vision allowed a clear view of the elongated shape, oriented N-S, with a brighter stellar core.” 

It would be almost twenty five years before I would observe this galaxy again, on September 26th, 2019.  

An astronomy friend, Richard Nugent from Massachusetts, visited both my wife Debbie and I, and were fortunate to be able to observe the galaxy that night.  We estimated the NELM at about 5.0, which is actually pretty good for my back yard this time of the year in the foothills of North Carolina. 

Using a 10-inch reflector, the galaxy was fairly easy to see with direct vision, at 114x.  When increasing the magnification to 174x, using a 12.5 mm eyepiece and a 1.9x Barlow, the galaxy appeared elongated and oriented N-S, with a brighter core.   

However, for a faint galaxy such as this, and using a 10-inch reflector in a moderate-plus light polluted location….just being able to recognize and see a few minor details can be an accomplishment or considered a success.  

I was pleased to be able to see the very faint double star, magnitudes, 13.5 and 14.0 located to the NNW of the galaxy.   (Magnitudes from NOMAD, and provided by special advisor to the Observer’s Challenge, Sue French)  

The double is actually a triple, but the third component is very faint at magnitude 15.7, which is far too faint for my 10-inch reflector.  I’m hoping that others using much larger telescopes were able to see this third star.  

Roger Ivester 

Pencil sketch:  10-inch reflector @ 174x 

Rogers NGC-7448 Inverted

Notes and pencil sketch by Sue French:

NGC 7448 is the brightest of five NGC galaxies that mark the corners of a nearly equilateral triangle with 28′-long sides. It sits at the triangle’s western corner. I first logged NGC 7448 in 1988 for the Astronomical League’s Herschel 400 observing program. Since then I’ve visited it a number of times, along with its buddies, through a few different scopes. My Observer’s Challenge sketch was done with my 254/1494mm (10-inch f/5.8) reflector at magnifications of 187× to 299×.

NGC 7448 appears fairly bright and elongated at 68×, with a 10th-magnitude star in attendance 2½′ east by south of the galaxy. At 115× NGC 7448 presents a moderate-size oval glow, twice as long as wide, that grows gently brighter toward the center. At 187× the galaxy shows a south-by-east tilt. Its large, elongated core looks brighter in the north. At 213× I estimate a size of about 1.7′ × 0.8′.

NGC 7465 shares the field of view with NGC 7448 at 68×, but it’s dimmer and roundish with a tiny, bright center. The galaxy sits 4′ east of an 8th-magnitude star and is tucked inside the western corner of a ¼° trapezoid formed by that star and three others, magnitudes 9 and 7. At 115× the small glow of the galaxy is easily viewed. Its core is tipped NNW and harbors a tiny bright nucleus. At magnifications of 187× to 299×, the core grows brighter toward a stellar nucleus and the faint halo is just a thin coating of fluff that slightly rounds out the galaxy’s profile.

NGC 7463 emerges as an east-west glow at 115×, dwelling just 2½′ WNW of NGC 7465. At 213× it shyly offers an elusive stellar nucleus and has a very elongated façade. At 299× NGC 7463 maintains an almost uniform surface brightness.

NGC 7464 is a tiny little thing dangling south of the eastern half of NGC 7563. I was only able to spot it during one of my observing sessions. With averted vision at 299×, I could catch repeated glimpses of the galaxy as a round dot. It was difficult to see, and I couldn’t hold it steadily in view.

Together NGC 7463, NGC 7464, and NGC 7465 hold down the western corner of the galaxy-pinned triangle. 

NGC 7454 is parked on the triangle’s northern point and is visible even at 43× as a tiny smudge off the ESE side of a 11½-magnitude star. A 9th-magnitude star lies 4½′ east by north. The galaxy is faint and somewhat oval at 68×, and 115× reveals a relatively large, bright, oval core. In addition to the 11½-magnitude star near the galaxy’s WNW side, the higher power captures a 13½′-magnitude star a little farther away to the NNW. NGC 7454 grows gently brighter toward the center at 187×, and at 213× I estimate the visible size as about 1′ × ⅔′.

I’d hoped all the galaxies would fit in my 187×, 32′ field of view, but that wasn’t big enough, so I cheated and nudged the scope north to get NGC 7454. I also used higher magnifications to add some of the details. Sketching stars, I began with those near the galaxies and brighter field stars. For three nights it kept clouded up before I could try to get the rest, so I decided leave the sketch as is. North is to the left and west is up. 

NGC 7488 group c inv

Mario Motta image:  32-inch telescope

See attached, 90 mins exposure on NGC 7448. Wiki says it is 80 million LY away, about 60,000 LY across. Notable for “detached spiral arm segments” which I think you can easily see in my image. Interesting object.

Taken with 32 inch scope SBIG STL 1001E camera, 500 seconds subs, 90 mins total exposure.  Processed in pixinsight. 

NGC7448

The Importance of Taking Notes and Making Sketches For Future Reference

November 7, 2019

I wanted to share information concerning an observation I made on April 20, 1993.  It’s a testament that documenting and taking good notes is indeed a good thing!   

Forward to February 1994: 

While reviewing my logbook, I discovered that I’d not followed up on an object viewed on 20 April 1993.  The primary object was NGC 3893, an 11th magnitude galaxy in Ursa Major.  While making my sketch of this galaxy, I noticed a smaller, much fainter object, SE of NGC 3893.  

So, while browsing through my logbook, I saw my notes that said:  “follow up on this observation.”  However, it would be ten months later (February 1994) before going back and checking data.   

I checked Burnham’s Celestial Handbook, Tom Lorenzen’s 1000+, and the Tirion Sky Atlas 2000.0 only to find that none of these sources listed a companion galaxy.  I then went to the NGC-2000.0 Catalog by Roger Sinnott, and found the companion listed as NGC 3896, a very faint and small 14th magnitude galaxy.  

If I had not sketched NGC 3893, most likely I would have missed NGC 3896.  And, if I had not noted  the companion, I probably would never have checked any reference material.  

This might be a good story in favor of being sure to document your observations.  

Roger Ivester

A newer pencil sketch of the galaxy pair, made April 1st 2014 

My original pencil sketch from the night of April 20th, 1993, which spawned my  interest in this galaxy pair.