For each photograph I added a finder chart, using a variety of planetarium software for field generation. There is at least one master chart for each constellation as a whole and individual finder charts for every object printed at a scale of five arc minutes/inch with stars to the limit of the GSC. These were all hole punched and matched to the photos on facing pages. I then went back to the planetarium programs (MegaStar, SkyMap Pro, and Deep Sky 1999 & 2000) and pulled up any information each had on the individual objects, as well as any field objects or companions. I decided to use the information from the LEDA database in SkyMap Pro, as it seemed to be the most accurate and up to date in its information, probably as a result of it being frequently compared to the extensive NASA Extragalactic Database for accuracy. I took the basic information from the database and copied it to each object printout. I included catalog numbers, Arp number, magnitude, surface brightness per square arc minute, size, galaxy morphological type, position, and redshift corrected to the 3° Cosmic Microwave Background. Because it seems to have the best positional and object orientation data, the individual finder charts are printed from MegaStar.
The notebooks were hauled out to the field and used, at first, to star hop my way to the objects. After about a year of this, I upgraded from a 12.5" JMI NGDob to a 16" AstroSystems Telekit with encoders and the Tangent DSCs. This made object location much more efficient, although my observing friend on this project still star hops with his 20" Obsession and bags as many targets as I do each night. This has more to do with how we observe each object, rather than with finding them. More recently, we have been using a laptop with MegaStar and Real Sky in the field since the GSC alone does not have all the field stars needed to positively identify some objects. Very recently, we added the USNO A2 to the MegaStar stellar database. Since that catalog contains field stars to 23rd magnitude, lack of them is no longer a problem. My observation notes were first jotted in the margins and on the finder charts of the printouts. With more emphasis on using a laptop in the field, I have begun using a standard spiral bound notebook for field notes. These primarily serve to jog my memory the next day so that I can try to make coherent observation notes in digital format. Believe me, it can be a challenge to make some of my notes coherent! So, having finally located and recorded the objects, this leads me to...
First and foremost, be patient. This is a marathon, not a sprint. If you just dash from object to object with a quick glance to confirm that there is something in the eyepiece, you end up not really seeing anything but the gross impression of the field. As a good friend would say, "you're looking, but you're not seeing". It is not unusual to spend anywhere from 20 minutes to over an hour on each object teasing out more and more detail. Just about every object in the Atlas that I have observed has rewarded my attention with more detail. If you do not finish that constellation this year, there is a very good chance that the object you missed will be in the same place next year.
Second, do not be afraid to use moderate to high magnification. The night's seeing will dictate what you can use, but it still is amazing to me how much more detail I can pull out of each target with that next shorter eyepiece. With what I have learned while doing this project, I find that I am constantly going back to previously observed targets, trying them at higher power than I would have thought that I could use on them, and finding that I had missed some faint details. If you have an observing buddy with larger aperture, don't hesitate to bug him or her to point at the same target. They might get hooked on viewing Arp Objects, and you can get still more detail in your observations. The only way to detect the dimmer galaxies, let alone see any detail, is with fairly high magnification. I used to think that a 9mm Nagler giving 233x in my scope was adequate. Now I no longer think that way, bumping things up to the 8mm Radian or the 7mm Nagler (or even higher.) There was a night, not too long ago, that we found ourselves all the way up to the 3mm Radian in the 20" f/5, but those nights are unfortunately rare.
Third, and probably as important as any other step, have fun. Most of us do this for enjoyment. If it becomes work, then you are going at this the wrong way.
Arp 185 - NGC 6217 - m11.8 sb 12.9 3.0'x2.4' SBb - 16h32.7m +78°12'. Arp Classification - Galaxy with narrow filaments. This is the only Arp object in Ursa Minor, but is worth seeking out. A fairly bright and large object, it is easily visible in any scope over 6-8" in size. In my 12.5" at 119x (N12) it is elongated NS about 2'x1.5' with a bright nucleus. At 159x (N9) it showed a bar on the W side running NS. This bar seemed to be off center to the W. In a 20" f/5 at 212x (N12) the off center appearance becomes very obvious, looking like a backwards "D". The arm to the east has a mottled appearance from the N side curving around to the east.
Moving on to Draco...
Arp 30 - NGC 6365 A&B - 6365A m14.6 1.1'x1' SBc - 6365B m14.8 sb 14.2 1.1'x.2' Sd 17h22.8m +62°10.3'. Arp Classification - Galaxy with one heavy arm. In this there seems to be some contradiction, as this system in the Arp Image is obviously an edge-on spiral seen projected against a face-on spiral. One arm of 6365A is slightly more predominant, so maybe this is what Dr. Arp is referring to. In the 16" at 233x this is a very faint system barely detectable with a magnitude 10.2 field star lying 1.4' to the NE. At 298x there is a faint 14th magnitude double star 1' to the NE and a 14th mag star 1' to the SW with the galaxies between them. 6365A is a small very faint round glow about .5' in diameter. Occasionally a stellar nucleus would pop into view, and when it did 6365B would then appear as a small bar to the N elongated to the NNE about .4' in length.
Arp 38 - NGC 6412 - m12.3 sb 13.4 2.5'x2.1' Sc 17h29.6m +75°42.3'. Arp Classification - Galaxy with low surface brightness companion on arm. In the 12.5" at 119x it was a faint oval glow elongated NS about 2'x1.5' in size with a brighter non-stellar nucleus. There are magnitude 8 and 10 field stars in the field that made it hard to see. At 159x there was still no sign of the companion. With the 16" at 233x (N9) there was a slight brightening at the N end of the main galaxy in the position of the companion that exhibited some central brightening.
Arp 81 - NGC 6621 & 2 - 6621 m13.6 sb 14(?) 2'x.7' Sb/p 6622 m 13(?) sb 13(?) .4'x.2' S/p 18h12.9m +68°21.8'. Arp Classification - Galaxy with large high surface brightness companion. In the 16" at 298x (N7) this is a nice double system elongated NW-SE about 2'x.5' in size. 6621 has a small bright almost stellar core with a small nuclear region surrounding it. It has small bright arms extending NW-SE from the core about .4' in length. There is a very faint haze starting from the NW arm sweeping around to the SE that pops in and out with averted vision. 6622 is in contact with 21 at the end of the SE arm and is slightly elongated perpendicular to the axis of the main galaxy and has fairly even brightness with very little central brightening. The arms of 21 are almost as bright as 22.
Arp 124 - NGC 6361 MCG +10-25-3 - 6361 m13.9 sb 13.5 2.2'x1.6' Sb - MCG +10-25-3 m15.6 .5'x.3' E 17h18.7m +60°36.4'. Arp Classification - Spiral Galaxy with close perturbing Elliptical. In the 16" at 298x 6361 is an elongated edge-on about 2'x.5' extending NE-SW. There is a group of faint stars surrounding the galaxy. The one of them located 1' W of the SW tip of the galaxy is actually the MCG elliptical. Closer examination shows it to be barely non-stellar with just a tiny amount of fuzz surrounding it.
Arp 293 - NGCs 6285&6 - 6285 m13.5 sb 15 1.3'x.6' Sa/p - 6286 m13.3 sb 14.7 1.3'x1.1' Sc/p 16h58.5m +58°56.3'. Arp Classification - Double galaxies with wind effects. In the 16" at 233x these two are a small faint pair with 6286 about 1.5' to the SE of 6285. 6285 shows only a small .5'x.2' central bar with just a hint of central brightening. The arms were not visible in the eyepiece. 6286 is an edge-on that was elongated NE-SW about 1'x.3' in size. The core region is slightly broader than the disc with no central brightening.
Arp 310 - IC 1259 - PGC 60323 & PGC 60325 - PGC 60323 m15.9 .8'x.6' S? - PGC 60325 m14.3 .3'x.3' SO/p 17h27.5m +58°30.9'. Arp Classification - Double Galaxy. The catalogs and various sky charting software seem to be a bit confused about this system. The IC 1259 designation is applied to both PGC 60323 and 60325. The discoverer in the IC saw the system as a whole and it was later observers who discovered the duplicity of the system while examining POSS plates, as it is listed as two galaxies in the PGC, MCG and the CGCG. In the 16" at 298x they are a nice sight with two stellar nuclei separated by 13" in a common envelope about 1' in diameter. There is a mag 14 star on the east side of the envelope that makes this object look like it has a triple nucleus. A mag 12 star lies about .5' to the NE. Also in the field are three other galaxies, IC 1259, IC 1260 and KAZ 140. These are m14.6 .8'x.7', m15.7 .4'x.2' and m15.8 .6'x.5' respectively. IC 1258 lies about 2.5' to the SSW of 59, IC 1260 is 2.4' to the ESE of 58 and KAZ 140 is 2.5' to the SSE of 58. The four of them make a pretty diamond of faint galaxies all within a 4' diameter circle. All four of them combined are also ARP 311, so you get two Arps for the price of one.
Moving south to Boötes brings us several interesting systems...
Arp 42 - NGC 5829 & IC 4526 - 5829 m13.4 sb 14 1.7'x1.5' Sc - IC 4526 m16.6 .4'x.3' S 15h2.7m +23°19.5'. These two along with PGCs 53702, 53703 and 53720 make up Hickson 73. Arp Classification - Spiral with low surface brightness companion on arm. In the 16" at 233x 5829 shows a small core about .3' in diameter surrounded by a very very faint haze about 1' in diameter. IC 4526 is an extremely faint barely non-stellar point of light that would only pop into view occasionally with averted vision. There is a mag 12.2 field star that forms a 70° angle with these two that makes this a difficult field in the 16. This seems to be common with quite a few Arp galaxies, they can be so faint that it does not take much of a stellar presence to mask detection. With the sky conditions this night I was not able to detect the other members of this group. This group is located on the N edge of AGC 2017, so there are quite a few faint galaxies available in the near area for those with large aperture scopes.
|Arp 49 - NGC 5665 - m12 sb 13.6 2.1'x1.3' SBc 14h32.5' +8°4.5' . Arp Classification - Spiral galaxy with small high surface brightness companion on arm. In the 16" at 233x this object has a triangular irregular shape with no apparent core about 1.2'x.7' in size, with the longer dimension running NS. There is a faint extension about .5' in size running E with a very faint stellar object at the end of the extension. In June 2001 I was lucky to receive a four night observing run at the Meyer Womble 28.5" binocular telescope run by the University of Denver on top of Mt. Evans west of Denver at 14200'+ altitude. This was one of several Arp galaxies that I both observed and imaged during this run. The 28.5" twin tube telescope is an f/21 classical Cassegrain system on an English yoke type mount. We would image with one tube while guiding with the other. Using a 55mm plössl yielded 278x. It made this galaxy much more apparent, but there still was no obvious core. The companion on the extension to the east was very easy visually, but was still stellar in appearance. The faint extensions to the south that are in the Arp photograph were not seen visually, but do show up on the CCD images that we took. It would be interesting to see a spectrum of the stellar companion since, according to Dr. Arp, this is possibly a QSO that is in the process of being ejected by the host galaxy.|
Arp 69 - NGCs 5579 & 80 - 5579 - m13.6 sb 15.4 1.9'x1.4' Sc 14h20.5m +35°10.9' - 5580 - all the catalog information says that these two galaxies are the same object. However, when giving the Arp photograph a careful scrutiny, it becomes apparent that there are two face-on spirals superimposed. They are interacting, with many HII regions. Arp Classification - Spiral galaxy with small high surface brightness companion. In the 16" at 233x 5579 & 80 are a faint oval about 1'x1.5' aligned NS. They have a bright non-stellar nuclear region that appears to be slightly oval NE-SW. About 2' S there is a mag 13 field star. In the Arp photo there is a small edge-on galaxy just south of the field star, but I did not detect it this night. Gives me something to shoot for next time.
Arp 90 - NGC 5930 & 29 - 5830 m13 sb 11 1.8'x.8' SBb/p - 5829 m13 sb 13.9 .9'x.8' Sab/p 15h26.2m +41°40.2'. Arp Classification - Spiral with large high surface brightness companion. In the 16" at 233x 5930 is a large oval about 1.5'x.6' aligned NS with a bright oval nuclear region around .6'x.4' brightening to a almost stellar core. The faint outer arms merged with the faint outer regions of 5929 on the west side of 5930. 5929 has a very bright stellar core surrounded by very faint nebulosity about .6-.7' in diameter.
Arp 117 - IC 982 & 3 - 982 m14 sb ? 1.3'x1.3' SO 14h10m +17°41.8' - 983 - m12.5 sb 14? 5.3'x4.6' SBa. Arp Classification - Spiral with companion galaxy close to and perturbing spiral. With the 16" at 233x there is a very bright field star (m8.8) 1.5' SE of the core of 983 making this pair extremely difficult. The core of 983 is evident, elongated EW about 1'x.6' in size. The surrounding arms are vvf due to the field star, but can be seen as a very faint haze. 982 is small, round about 1.2' in diameter brightening to a stellar core. 8' S of 983 in the field is NGC 5490C, AKA Arp 79, a m14 SBc spiral 1.1'x.07' in size. The Arp classification on this is a spiral with a large bright companion, but it looks in the eyepiece like a small core with a heavy arm on the south side. NGC 5490 is also in the field, 4' SW of 5490C.
Arp 136 - NGC 5820 - 5820 m12.4 sb 14.9 1.6'x1' SO/p 14h58.7m +53°53.2'. Arp Classification - Galaxy with nearby fragments. At 233x 5820 is a bright oval lying EW about 1.5'x.7' in size. It brightens rapidly to an oval core. At 298x there is a very faint stellar point about 1.5' to the south that would occasionally appear elongated. This was the only fragment that I was able to definitely detect. There are a pair of bright field stars about 8' to the east that have to be moved outside the eyepiece field in order to be able to see anything around this object. NGC 5821 is 4' NE of 5820, a magnitude 14.5 very faint oval. UGC 9632 is 9' to the SW of 5820, a very faint m14.9 bit of fluff with a stellar core. All three fit nicely in the field of a 7mm Nagler.
Arp 178 - NGC 5614 & 15 - 5614 m11.7 sb 12.7 2.4'x2' Sab/p 14h24.2m +34°51' - 5615 m15 .2'x.2'. Arp Classification - Galaxy with narrow counter tail. In the 16" at 262x 5614 is a 2' diameter glow with a .4' diameter nuclear region noticeably offset to the northern part of the galaxy. About .5' to the NW of the core of 5615 is a faint stellar point within the envelope of 5614. 2' N of 5614 is 5613, a small .5' mag 16 very faint bit of fuzz with a slightly brighter core. The published redshift of this shows that it should be twice as far as 5614, 8929kps vs 4066kps for 5614 & 15, but the deep photograph from the Arp Atlas shows a very faint outer ring surrounding 5613 that makes one wonder about interaction between all these systems. In the 28.5" at 276x (55mm plössl) there were hints of the tail that stretches from the N to the W of 5614, but there was no definite visual detection of this feature.
|Arp 199 - NGC 5544 & 5 - 5544 m13.2 sb 14 .9'x.9' SBO-a 14h17.1m +36°33.9' - 5545 m14 sb 14 1'x.3' Sbc. Arp Classification - Galaxy with material ejected from nucleus. I wonder about this classification, as the Arp photo clearly shows a pair of superimposed galaxies. In the 16" at 233x 5544 is small, round .5' diameter with a brighter non-stellar nucleus. There were hints of very faint outer arms, but no definite detection. 5545 is elongated to the NE of 44, in contact with the core region. It is 1'x.3' in size with the inner .3'x.3' core region brighter than the outer arms. The arms were easily held with averted vision as rounded arcs to the NE and SW. In the 28.5", 44 was much easier with the outer arms visible as a faint haze surrounding the nucleus about .8' diameter. The arms of 45 showed some brightening with the arc to the NE having the end towards the nucleus visibly brighter.|
Arp 297 - NGC 5755 - m15.1 sb 15.2 1.3'x1' SB/p 14h45.4m +38°46.8'. Arp classification - Double galaxy with extensions. Actually, in this field there are a pair of foreground galaxies that also seem to fit the Arp classification of Galaxy with large high surface brightness companion at the end of arm. These are NGCs 5754 & 52 located 3.1' S of 5755, so my description will also include these two and 5753. In the 16" at 300x 5755 was visible as a small faint irregular shape about .5' in size. It appeared slightly brighter on the N side of the object. In the 20" at 423x (6mm Radian) it was still faint, but was almost triangular in shape. NGC 5753, m15.1 sb 13.3 .4' diameter, was a small faint round spot with a brighter almost stellar core about 2' to the NW of 55. NGC 5754 lies 3' to the SW of 55. It is m14.1 sb 15.5 2'x1.8' SBb spiral. At 300x it is a 1' diameter object with a faint bar NW-SE about .5' in length, with a brighter core. The outer arms of this galaxy were not detected. About 1' to the SSE of the core of 54 is NGC 5752, a m14.1 sb 12.6 .5'x.2' Sb galaxy that on the Arp image is crossed by one of the arms of 54. In the 16" it is the brightest of the four, looking like a small dash aligned with the bottom edge of 54. All four of these galaxies fit into the eyepiece field of a 6mm Radian on the 20" scope.
Moving south to Serpens...
|Arp 72 - NGC 5996 & 5994 - 5996 m12.8 sb 13.8 1.7'x.9' SBc/p - 5994 m13.2 sb 14 .4'x.2' SBbc 15h47m +17°52.3'. Arp Classification - Galaxy with small high surface brightness companion. In the 16" at 233x 5996 is small about 1.5'x.7' with faint arms. It has a brighter bar about .4' in length running E-W. The arm on the W end of the bar curves to the N. It has a patchy appearance between the arm and the bar. The arm on the E end of the bar curves to the SW and is visibly longer than the other arm. 5994 is about 1' to the W of the end of this bar, being a small, faint averted only object about .3' in length. Both systems appear to be surrounded by a very faint haze.|
Arp 91 - NGC 5953 & 4 - 5953 m13.3 sb 14.1 2'x1.6' Sa - 5954 m13.7 sb 12.6 1.1'x.5' SBc/p 15h34.6m +15°11.6'. Arp Classification - Galaxy with large high surface brightness companion on arm. In the 16" at 233x 5954 is an oval about 1'x.5' elongated NS with a slightly brighter core. 5953 is small about .5' in diameter with a bright non-stellar core. there is a very faint haze surrounding it for about another .5'. 5954 is the easier of the two to see with direct vision, but the outer extremities need averted vision to be seen.
And a short skip over the border to Hercules...
Arp 71, 122, 172 and 272. These four objects are all in the Great Hercules Cluster, Abell 2151. An observing friend and I spent one entire July evening just exploring the small section of sky that contained these objects along with many other very faint galaxies. Every eyepiece field displayed a multitude of NGC, IC, PGC, and MCG galaxies. It is hard to express the awe we felt observing this area of the sky. In MegaStar AGC 2151 is given a dimension of 56' in diameter containing 87 galaxies, but given sufficient aperture you can trace faint fuzzies all the way to Abell 2197 and 2199 in the northern part of the constellation . This is considered to be the eastern portion of the Great Wall, which itself can be traced to Leo and beyond. But that is a subject for a future observing project, so back to the Arps.
Arp 71 - NGC 6045 and LEDA 84720 - 6045 m13.9 sb 13.3 1.3'x.3' SBc - LEDA 84720 m16.7 .6'x.4' SO 16h5.2m +17°45.4'. Arp Classification - Galaxy with small high surface brightness companion. In the 16" at 262x it is a faint edge-on streak about 1.2'x.3' aligned EW. It is very faint but easily held with averted vision. In a few moments of good seeing (about three times in 10 minutes) the companion would pop into view hanging down from the E end. At these moments it would look like the photo. To the NW 1.9' away is NGC 6043, a magnitude 15.5 small elliptical .7'x.4' in size. It has a stellar core surrounded by a very faint oval fuzz. 1.7' to the south is NGC 6047, a relatively bright magnitude 13.5 EO galaxy about .8' in diameter with a brighter non-stellar core. 3.7' due east is NGC 6050 and IC 1179, a contact pair of face-on spirals that look like the Siamese Twins in Virgo in miniature. They glow at magnitude 14.7 and 16.1 respectively. They will be discussed in more detail further below. Another 2' ENE from them is NGC 6054, a magnitude 15.2 elliptical bit of fuzz .8'x.4' in size. All these and more were in the field of the 8mm Radian.
Arp 122 - NGC 6039 & 40 - 6039 m14.5 sb 13.4 .8'x.7' E-SO - 6040 m14.5 sb 14 1.3'x.7' SBc 16h4.5m +17°45'. Arp Classification - elliptical galaxy close to and perturbing spiral. This is another interesting field located 10' W from Arp 71. At 262x in the 16" 6040 is oval about 1'x.5' aligned NE-SW. It has a very small occasionally stellar core. There is a faint haze extending S from the SW end that envelopes 6039. 6039 is about .5' in diameter brightening to a non-stellar core. 2.9' SE from 6040 is NGC 6041A, a magnitude 13.7 SBO galaxy that is 1.3'x1.1' in size. It was a small round glow about .7' in diameter brightening to it's core. About .7' W of 41 is IC 1170, a faint 15.5 magnitude bit of fluff about .4'x.2' in size. This barely visible speck of a galaxy was visible about 50% of the time. Much closer to the core of 41 is 6041B, a tiny magnitude 16.6 stellar bit that is located 18" SW from 6041A's core. This one would only pop into view for brief instants in either the 16" or the 20" scope, but it was detected in both instruments. 1.5' further SE from 6041A is NGC 6042. This E-SO galaxy is magnitude 13.9 and .8'x.7' in size. It appears much smaller in the eyepiece, about .4' in diameter increasing evenly in brightness to its nucleus. All in all, very pretty. Six galaxies in a line less than 5' in length.
Arp 172 - IC 1178 & 81 - IC 1178 m15.1 sb11.5 1.1'x.8' E-SO - IC 1181 m15.9 sb 13.5 1'x.8' SO-a 16h5.6m +17°36'. Arp Classification - Galaxies with diffuse counter tails. This pair is located 11' SE from Arp 71, and just keeps adding to this great field. At 262x in the 16" these two are a tight pair separated by 30". The nucleus of 78 is very much brighter than 81 and slightly larger with 78 being about 20" in diameter and 81 about 10 to 12" in diameter. The tails shown in the Arp photo were very definitely not visible in the eyepiece. The beauty of this field lies in the amount of faint galaxies visible at one time. With this pair on one side of the field and Arp 71 on the opposite side, there were 12 galaxies visible in the field of an 8mm Radian. MegaStar shows 14 galaxies centered on UGC 10190 and SkyMap Pro shows 19 for an 8mm 60° fov eyepiece.
Arp 272 - NGC 6050 & IC 1179 - 6050 m14.7 sb 14.5 .9'x.6' SBc - 1179 m16.1 .6'x.4' SBc 16h5.5m +17°45.4'. Arp Classification - Double galaxies with connected arms. This is the third Arp pair visible in the same 8mm eyepiece field. At 262x they are a pair of very small objects in an oval haze about 1'x.7' in extent. There were two nuclear brightenings in this haze but not very much detail. Still, I guess that the overall field more than made up for the lack of detail, especially considering that I spent more than 6 hours staring at four objects (and multiple other galaxies) in a cluster of galaxies more than 750MLY distant. I'm happy.
I will see you with the fall batch, and until then, Happy Hunting.....