Archive for November 2019

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, that spawned my  interest in this galaxy pair.