Some of the specific items for this month's challenge included:

   - Noticing the difference in appearance of the extreme ends of the galaxy - how are they different?

   - Looking for and describe the object that is between the Whale and its Calf.

   - Describing the texture of the galaxy - does it have a consistent or mottled texture?

   - Describing the areas that seems to animate this object.

   - Describing the star pattern that is southeast of the Whale.

   - Looking for a 13.5 mag star just north of the tail.

   - Describing NGC 4627, the Calf, and its position and relationship to the Whale.

NGC 4631 is a magnitude 9.8 edge-on spiral galaxy in Canes Venatici. The streak of the galaxy is distorted with a wedge at one end. In photos, it resembles a blue whale and is known as “The Whale.” A large number of stars in the central core have gone nova and are ejecting mass amounts of gas from the core, creating a superwind. Unfortunately, this wind can only be seen in X-ray photos. For visual observing, there is no indication this is happening. The galaxy is approximately thirty million light years away and is part of the NGC 4631 galaxy group. Its closest companion is magnitude 13.1 galaxy NGC 4627, an elliptical dwarf also known as “The Calf.” Together, they are known popularly as “The Whale and Calf.”

Although not technically part of the challenge, it is hard to view just the Whale and Calf without seeing NGC 4656/4657, the “Hockey Stick”, in the same field of view. Using a wide-field eyepiece, both pairs of galaxies can be squeezed into the field. NGC 4656 is another edge-on galaxy that has a companion. This companion, NGC 4657 interacts with NGC 4656 and distorts one end of the streak, giving the impression of a hockey stick. They were discovered by William Herschel in 1787. This magnitude 10.4 galaxy is a nice addition to the challenge.

Observations/Drawings/Photos

Roger Ivester: LVAS Member from North Carolina

The Observers Challenge for May 2010 includes two very unusual galaxies. These are NGC 4631 and its faint companion NGC 4627. They are easily seen in the same low-power field with another interesting galaxy, NGC 4656.

All observations were made from my moderately light polluted backyard, located in Boiling Springs, North Carolina, twenty minutes south of the southern rim of the South Mountains.

All observations were made using a 10-inch f/4.5 reflector. It is difficult for me to observe NGC 4631 and NGC 4627 without also observing NGC 4656. All galaxies will easily fit into the same low power field of view. Just off the NE edge of NGC 4656 is a brighter section that juts off toward the east and is designated NGC 4657. Many do not consider NGC 4657 to be a companion galaxy, but a part of NGC 4656.

The 10-inch presents NGC 4631 as large, highly elongated, with an uneven texture and a much brighter middle. The entire galaxy is very mottled throughout, and it is oriented E-W, with the western end fading gradually to a very thin point. The eastern section has greater concentration and is much broader with a blunted end. A magnitude 12 star lies just off the north edge of the center section. Approximately three arc minutes NW of this galaxy is the faint and small 12.3M companion galaxy, NGC 4627. It can be very difficult, even with the 10-inch from a suburban location.

NGC 4627 appears very small, mostly round, with low surface brightness. Averted vision is most often required.

NGC 4656 is elongated, with a slightly bulged and brighter middle. The NE section is brighter and has much greater concentration. The SW part is very faint, and fades outward very gradually, but has a very faint brightening on the tip. Averted vision is required to see the full extent of the SW section.

NGC 4657 can be difficult. It is a slightly brighter part that is attached to the NE end of NGC 4656, and curves toward the east. Averted vision is required. A good night and higher magnification is necessary to see this most interesting and unusual object.

Fred Rayworth: LVAS Member from Las Vegas

On May 7, 2010, I had my first chance to observe these two objects. However, it was not at an ideal site and I was less than thrilled with the results. On May 15, 2010, I had a better night from what started out as a disappointing one.

I opted to skip the Cathedral Gorge Spring Fling because I didn’t think the weather would pan out. However, it did and at first I was upset I didn’t go. I had decided to go local and joined a group of friends at Redstone Picnic Area on the north side of Lake Mead. As I drove out there, the sky started to close in with high thin cirrus clouds. I was almost convinced to turn around but was glad I didn’t. As it got dark, the sky opened up and was surprisingly dark and clear. I couldn’t complain about the wind or temperature either, as I stayed in a short-sleeved shirt the whole night.

Using my 16” f/4.5 LightBridge, with 26mm Q-70 (70X) and 17mm Hyperion (101X) eyepieces, I had my best view yet of these two fine galaxies.

NGC 4631 presented a fat elongated streak with a wedge shape at one end. This wedge shape gave it the vague outline of a gray whale, hence the name. Within the thickest part of the bulge and around the wedge, I detected mottling, a mix of light and shadow, though it didn’t always come through with direct vision. The 26mm showed it framed nicely with just a vague hint of detail. By far, the best view was with the 17mm Hyperion. With the higher power and smaller field, it framed the galaxy along with its companion at the right setting to be comfortable. It was at this power (101X) that I saw the most detail.

Just off the edge of the central bulge (for what it is) there was a star which sat between it and the Calf, NGC 4627. Also, in the “tail” of the whale was another dimmer but still noticeable star just off the edge and before the tip of the tail. There may have also been a tiny star just off the tip of the tail and on the same side of the tail as the other star.

NGC 4627 was a very small medium-bright oval tilted at an angle to the plane of NGC 4631. It had no real distinguishing features except that it was definitely oval shaped. I spotted no core and no other features to speak of.

Within the same field of view in the 26mm Q-70, I was able to squeeze in NGC 4656 and NGC 4657, also known as the “Hockey stick.” This unusual pair of galaxies take on the hockey stick shape in the way they interact. NGC 4656 is the larger of the two and presents as a nice streak, a bit smaller than NGC 4631. However, visually, one end of the streak is bent and that bent part is NGC 4657. It is a smaller and much dimmer galaxy that is interacting with NGC 4656. NGC 4656 appeared a bit mottled around the thicker area of the core but NGC 4657 was just a bend in that flat streak. It showed no detail at all and looked like part of the other galaxy. I could not separate them visually. The center bulge of NGC 4656 showed brighter and gave the impression of a central core, though it was not stellar.

Rob Lambert: LVAS Member from Las Vegas

NGC 4631 and its companion NGC 4627 are interesting objects that can inspire imagination in the mind of a celestial observer, especially an avid one that has deprived himself of sleep during a couple of all-nighters. I remember the first time I observed this object in February 2009. They made me think of the Seaview, the futuristic submarine from the TV series Voyage to the Bottom of the Sea, and its flying mini-sub hovering overhead (Google SSRN Seaview to see what I mean). The eastern end of the Whale is larger and wider than the more narrow tapered western end, giving it somewhat the appearance of a shovel-nosed shark, as viewed from the side. (See the Mallincam image of NGC 4631 at the top of the article.)

The Whale appears to be at least 20 times larger than the Calf and its overall texture is quite mottled, with several bright spots along its length. One of the dimmer spots near the eastern end lends itself to be the eye of the Whale, while another brighter one between the nose and the center can be imagined to be the Whale's heart. Other spots in the center of the Whale's body make its center brighter and larger than its extremities. Letting your imagination loose, you can even imagine the black and white color patterns of an Orca (Killer Whale).

The much smaller elliptical-shaped galaxy, the Calf, hovers over the back of the Whale, just to the north and slightly west of the magnitude 12 star that almost touches the Whale's back. The smaller galaxy's brightness is about the same as the dimmer regions of the Whale's body.

There is a dim, probably magnitude 13 or magnitude 14 star, or maybe even double star, just north of the western tip of the Whale's tale. An interesting star pattern is located southeast of the galaxy's eastern end. It looks like a slightly distorted backwards version of the Big Dipper with Mizar and Alioth missing out of the handle.

NGC 4656/4657, the Hockey Stick, is located approximately 45’ southeast of the Whale. Because of the almost right angle formed by these two objects, I believe these are two interacting galaxies, rather than part of the same galaxy, as some believe. In any case, the combination makes for quite an irregular-shaped object with an uneven texture or distribution of matter across its length. To the east of NGC 4631 and NGC 4656, there is a relatively straight chain of at least six mixed-magnitude stars that stretch almost equidistant from the tip of NGC 4631 to a point the same distance above NGC 4656. The Whale almost appears to be chasing this string of stars.

The images I captured are not intended to be pretty magazine pictures, but rather video enhanced versions of what one might see at the eyepiece of a larger telescope. Only a couple of image frames are stacked with a dark frame to remove hot pixels. No additional enhancement or processing of the images was done. The images depict what was seen on my monitor at the time the images were captured. The wide field view containing NGC 4631 and NGC 4656 is a 20-second exposure captured through my Orion ST120 at f/2.5, which depicts a 1.5-degree FOV. The larger image of NGC 4631 was captured on my 10” LX200GPS at F/5.0 and depicts a 0.3-degree FOV.

David Blanchette: LVAS Member (Outreach Director) from Las Vegas

I captured these images from Dante's View in Death Valley, May 14, 2010. The first one just has the Whale and Calf while the second one includes NGC 4656/4657 (colliding galaxies) in the opposite corner of picture.

I hope people don't get the wrong impression of Death Valley, i.e., the most wonderful, darkest, perfect place to photograph the stars. The place can drive one to drink! One can usually find the Las Vegas glow off to the southeast during the club’s twice-yearly star parties at the Furnace Creek airport (190 feet BELOW sea level.) Of late, the skyglow of Los Angeles is noticeable to the south. The skies overhead can be quite black, but often contain just that touch of gray that washes out the contrast between the object and the background.

Last Friday, when I took the photos, I was at about 5,200 feet above sea level. A weather front had just passed through, and there had been some daytime-heating pop-up clouds, and so there were still some thin clouds lurking around. Las Vegas was surprisingly bright. However, about 11pm, the light dome suddenly shrank, and the overall brilliance declined, as if 30% of the lights had been turned off. Knowing this to be ridiculous, I realized that there had been some clouds over Las Vegas. Being at 5,000 feet and looking over the low hills and mountains that normally protect the view from the airport, the clouds really served to reflect the Vegas lights to the top of Dantes View.

I would like to try the spot again, when there are no clouds anywhere near the site. I'd like to see how the elevation and the clouds caused trouble.

Dr. James Dire: LVAS Member from North Carolina

The Whale Galaxy, NGC 4631, is a magnitude 9 edge-on spiral galaxy in the constellation Canes Venatici. The galaxy can be found approximately five degrees south and three degrees west of the third magnitude star, Cor Caroli. There is a faint galaxy, NGC 4627, located 2’ northwest of the center of the Whale. NGC 4627 is a dwarf elliptical galaxy affectionately called the "Pup" (or Calf). The Whale Galaxy is approximately 14.4’ by 2.2’ in size, while the Pup is 2.2’ by 1.8’.

The Whale Galaxy is asymmetrical, the distortion thought to be caused by gravitational interactions with the Pup. Distance estimates for the pair range from 10 to 30 million light years, which shows the uncertainty in astronomical calculations.

I first saw the Whale and Pup at a star party in the winter of 2006-7 in Bob Eskirdge's Dob at a dark site location in Rutherford County North Carolina, known to local Piedmont astronomers as "The Slab". Soon thereafter, it was one of the first galaxies I shot using a CCD camera. The attached image was taken with an SBIG ST-2000XCM CCD camera on an 8” f/7 Newtonian. This 15-minute exposure clearly shows the dark lane structure along the edge of the spiral galaxy and many HII regions where ongoing star formation is probably occurring. Note how much more extended the visible edge of the galaxy is on the side where the Pup resides.

Sue French: S&T Columnist from upstate New York

This month's Observing Challenge was for NGC 4631 and its little companion NGC 4627. However, I've always enjoyed viewing these two together with NGC 4656/57, so I decided to sketch the combination.

I first logged these galaxies in 1985 while looking through a 36-inch Cassegrain under beautifully dark skies at MIRA (Monterey Institute for Research in Astronomy). Needless to say, they were gorgeous.

This time, I used my 130mm f/6.3 refractor at my semi-rural home in upstate New York. The sky is hardly pristine so close to Schenectady. A light pollution map places me in an orange zone, but I have the decided advantage of no glare from local lights.

The seeing and transparency high in the sky were good during my sketch, but only fair at the altitude of the targets at around 10 PM EST in early March. I chose a magnification of 117X with a wide-angle eyepiece. This is the highest power at which the galaxies would share the field of view.

NGC 4631 is very, very pretty and highly textured. It's brightest at its widest part, which is a little east of center, and along most of its northern flank. A faint star is plainly visible resting on the Whale's back. NGC 4627 can be seen with direct vision but shows up better with averted.

NGC 4656 is considerably fainter and has two bright patches, one at the northeast end and a much larger one northeast of center, both mottled. The latter has a bright spot on its west-southwestern edge. The galaxy's hook, including NGC 4657, is faintly visible with averted vision.

More and more stars popped out as the galaxies slowly climbed the dome of the sky, but I only added a few of them to the sketch. The sketch is mirror-reversed and done with sketching pencils on a blank 5 X 8 index card. I used Microsoft Picture Manager to change the image to white on black and made small adjustments to the contrast and brightness so that all four objects would show on my monitor.

I wanted a closer look, so I boosted the power to 164X, but the galaxies no longer shared the field. NGC 4627 was then easily visible with direct vision as a small oval tipped north-northeast. NGC 4657 was also a bit more apparent and elongated north-northwest to south-southeast.

Frank Barrett: LVAS Friend from North Carolina (www.celestialwonders.com)

NGC 4631 is the Whale while NGC 4627 is the Pup (Calf). I took this image on 4/6/2010 from my observatory in Gastonia, NC.

I used a Meade 10-inch LX200R, with a 2,800mm focal length giving it a focal ratio of f/11. I took a luminance exposure of 270 min, a color exposure of 180 min and combined the images. I used a SBIG STL-11000M camera. My mount was a Losmandy G11 w/Ovision worm upgrade.

Buddy L. Barbee: LVAS Friend from North Carolina

When I first learned about the LVAS Observers Challenge and the list of objects for 2010, I was excited because I have never tried to observe many of the objects on this year's list. This was true of May's challenge objects, NGC 4631 and NGC 4627, the Whale and Calf galaxy system. While camping Easter week, I got my first look at these galaxies. They looked beautiful in my 4-inch TV-102 with NGC 4656/57 in the same field-of-view at 67X. I wanted to use more aperture for a better view to sketch these galaxies, so I didn't sketch them while camping.

I recommend that when the opportunity presents itself, seize the moment and sketch because I didn't know that I would be trying to observe this group five more times without success over the next month, due to haze. Little did I know that this was going to be my best view of them for a month. Finally some club members and I made a trip up to the Blue Ridge Parkway for an evening of viewing. We sat up at the Mt. Airy Granite overlook, near mile post 203 in southwestern Virginia. This site is approximately 60 miles north west of his house, has a good view of the horizon, and magnitude 6 skies on a good night. It turned out to be a short night, though. With the sun setting at 8:06 PM and an almost full moon rising at 10:56 PM, we only had about an hour of really dark sky. It was worth it. This was my sixth attempt to view this galaxy since camping. The trip was well worth it because I finally had a good view of NGC 4631 and its companion.

I was using my wife's C-6 telescope. The C-6 is a great little 6” SCT. I am always impressed with the views this scope gives. Using my 24mm Panoptic eyepiece for a magnification of 67.5X, NGC 4631 is a bright galaxy that is easily seen with direct vision. The galaxy is oriented almost in an east-west direction with the brightest part just east of center. The eastern end of the galaxy is noticeably blunter than the western end that fades to a point. There is a magnitude 13 star that is just north of the galaxies core, which is best seen with averted vision. NGC 4627, the companion galaxy known as the Calf, is very faint and seen about half the time with averted vision.

Once again this was a wonderful night observing with friends under a beautiful sky.

Other Notable Observations

David J. Eicher, Galaxies and The Universe, An observing guide from Deep-Sky magazine, The Galaxies of Canes Venatici, by Max Radloff

NGC 4631, it is an edge-on spiral without a nuclear bulge or dust lane. Irregular dust patches and star clouds can be seen along its length as areas of varying brightness, especially at higher magnification. There are also irregularities in the outline, similar to but not as prominent as those in M82. NGC 4627, can be seen just slightly NW of the center of NGC 4631. Between the center of NGC 4631 and NGC 4627, and just off the edge of the larger galaxy (NGC 4631) is a foreground star.

Tom Lorenzin, 1000+ The Amateur Astronomer's Field Guide to Deep-Sky Observing

NGC 4631, mag. 9.7, 13' X 1' extent; very large, bright, ENE-WSW-oriented slash with little center brightening; edge-on spiral! EL GAL NGC 4627 (13M; 2' diameter) 1.5' W and a little N of NGC 4631's center; good supernova prospect; 30' NW of DBL GAl NGC 4656-7

Observing Handbook and Catalogue Of Deep-Sky Objects, by Christian Luginbuhl and Brian Skiff, Cambridge University Press

NGC 4631 is visible as a smooth, weakly concentrated bar in 6 cm (2.4”), elongated in pa 85°. Only NGC 4631 is visible in 15 cm (6”). It is a 10' x 1'.5 streak with a mag. 12 star on the N edge of the brightest part of the mottled spindle. 25 cm (10”) shows NGC 4631 as 13' x 1'.5 overall. NGC 4627 is faintly visible 2'.7 NW of the brightest part. The W end of the halo tapers to a thin, long point; the E end fades out more abruptly. The mag. 12 star lies on the N edge near the broadest part; a mag 13.5 star lies 8' W of this star on the N flank. A small knot is visible 20" S of the fainter star; the halo extends 2'5 W of this star. Moving E, the bar grows wider, and several bright and dark markings are visible with stellarings among them. About 1' SE of the mag 12 star is the brightest blob, which exhibits some concentration. A beautiful galaxy! Next to this exceptional object NGC 4627 is small and faint. The poorly concentrated halo extends only to 50" x 30", elongated NNE-SSW.