#53 Sagittarius Deep Sky Plans

If you had to nominate one constellation as "best of" for northern deep sky observers, which would you choose?  Virgo, with all of those bright galaxies and Messier objects?  Scorpius, with its clusters and nebulae?  Or perhaps Orion, with the most amazing nebulae available.  I would argue Sagittarius. It has a reasonable number of NGC and IC objects (77), a consistently fine background when star hopping, plenty of worthwhile objects from other catalogs, and perhaps the widest variety of objects in any one constellation. There are open clusters galore, along with nearly as many globular clusters. There are planetary nebulae, galactic nebula, and even a few galaxies.  Double and variable stars are positively glorious.  I have yet to mention that there are no less than fifteen Messier objects!

Best of all, Sagittarius is a summer constellation and on view during the best observing weather for us northern folk.  Trying to choose favourite constellations is a totally subjective exercise, as is choosing a favourite object in such a rich area.  I won't even try, at least until I have viewed all of them.  This may take a few seasons.  The one disadvantage of observing in Sagittarius is its relatively low position in the southern sky.  My latitude is 42 N.  I can comfortably observe stars and clusters to about -35 degrees on excellent nights, and on occasion, for certain objects, I can reach -42 degrees. However, finding nights in the humid summer when I can clearly see the southern sky is difficult, and a rare occurrence.  For that reason, I always have other, higher constellations on the go.  I am working in Aquila, Delphinus and Sagitta most nights. However, if and when the southern sky is worthwhile, off I go to Sagittarius.  So far I have barely begun my re-exploration of this amazing motherlode of deep sky treasures.  For now, I am concentrating on the sky in and around M 23.

Here is a simplified list of what I will be observing in Sagittarius.  Firstly, the fifteen Messier objects are:  8, 17, 18, 20, 21, 22, 23, 24, 25, 28, 54, 55, 69, 70, and 75.  Have I missed any?

In the NGC list there are:

19 open clusters

21 globular clusters

03 galactic nebulae, plus 2 more involved with clusters and having the same designation

06 galaxies (from my latitude--there are several more, but too low for me to attempt)

11 planetary nebulae

In the IC catalogue are:

01 globular cluster

10 galactic nebulae

06 planetary nebulae

From other catalogues of interest to me are:

33 open clusters

04 galactic nebulae

I am also seeking a minimum of 15 doubles, some of which I have seen previously with the 8" and recorded as worth viewing again, along with a few I could not split with that instrument.  Combined with my work in three other summer constellations, I am happily awaiting the last quarter moon phase and the next clear night closest to it.

Mapman Mike

#52 Summary #6: Mid-July to July 31st, 2014

     The two-week session from last quarter moon to first quarter moon brought us out to the observatory five times, with just over 17 hours of observing logged.  My work continued in Hercules, as I finished up two significant Abell searches there.  Last month it was Abell 2197, while this month it was Abell 2199.  This detailed but difficult work using the close up maps in the Uranometria appendices is one of my very favourite things to do.  I really wish that more of these detailed maps would be published!  I also added a few more galaxies in Bootes before calling off observations there until next Spring.  I really got to work in Aquila, and though most of the objects have been seen before using the old 8", it really is like seeing them anew with a 12".  I also began work in Sagittarius, something that will take several seasons to conclude, as my south skies are not my best skies.

Only two nights of the five had superior skies, and on the first one it clouded over by midnight.  However, the 2nd fine night stayed great, and we logged 5 hours of observing that night.  The biggest highlight of July? It would have to be getting back into observing in the summer milky way!  The richness of the background sky from a dark site is unbeatable, and there are distractions aplenty.  Here, then, is what I have been doing for the last two weeks.

HERCULES
I managed to observe Abell 2199 in one session.  I was after a total of 10 galaxies here, 7 of them from the NGC.  5 of them have the same NGC number!

Abell 2199--SkyView Images

In the center of the above image is eg 6166:  1'.9 x 1'.4:  V. 11.8; SB 12.8:  This large, bright galaxy lies near the center of Abell 2199.  Very close to it is eg 6166A, immediately south and in the 5 o'clock position.  Beside it on the left is tiny eg 6166D.  These two objects were easy to see at 150x, in the same field with 6166.  A bit further away and in the 2 o'clock position is eg 6166C.  Best seen at high power with averted vision, it was not difficult either.  For me, the challenge was seeing eg 6166B, in the 9:30 o'clock position.  It looks stellar in the photo, above.  Indeed, it is only 0'.4 x 0'.3, and V. 14.9 (sb 12.4).  Without such a good sky I doubt I would have found this one, but after a while it was glimpsed with a.v.  Many other small galaxies can be seen in the photo, but I was only after the 6166 group.

Very close by, in the 5 o'clock position and just outside the range of the photo is eg 6158:  0'.9 x 0'.6:  V 13.7; sb 13.1:  Compared to 6166A, B, C, and D, this one was a piece of cake!  It is in the same 100x field with 6166, though I could not see the smaller companions at this magnification range.  It is distinctly oval, faint but with a brighter middle.  I finished up here with UGCs 10349. 10367, and 10381.  All three were easy targets for the 12", and of some interest to observers.  U10381 was especially notable, a medium long, very thin slash.  When I finally found eg 6129  (actually in Corona B.) this completed my work with Uranometria Chart A3! (also see last month's summary for Abell 2197).

oc DoDz 5: 27':  This large open cluster of bright stars is half on Chart A3 and half off.  I observed it at 43x and 60x.  It lies just south of Abell 2199.  About 15 bright stars were counted.  A similar sized group is preceding.  It has about 20 stars, all much fainter than the actual cluster ones.

BOOTES
eg 5536:  1'.2 x 1':  V. 13.6; sb 13.6:  This pair of galaxies was seen easily at 125x, and then up 
eg 5541:  0'.8 x 0'.6:  V. 12.7; sb 11.8) to 200x.  Though 5541 is spotted first, it is 5536 that appears to have a bright middle.
eg I. 990:  This tiny, faint galaxy is not far from the pair just mentioned.  As it was a great night sky I gave it a try.  Success!
eg 5497:  1'.2 x 0'.7:  V. 14.1; sb 13.8:  Impossible without a great sky, though I did glimpse it on a night of bad transparency.

AQUILA
I have seen most of the deep sky objects here in previous years with the 8" scope.  I am redoing them all, plus adding several NGC objects not labelled on my earlier maps as well as several clusters from other catalogues.
oc6709:  15': V. 6.7; Br * 9:  This is the showpiece open cluster within Aquila.  Fond memories of this group in the 8".  It also looks fine in Deb's 6".  Three nice doubles in there, too.  Quite wonderful in the 12".  Recommended.
oc 6724:  3'; V 10; Br * 12:  Next door to 6709, though quite disappointing.  200x shows 8 stars in a tight group.
oc 6738:  15'; V. 8.3:  Bright and straggly at 60x, located north preceding a bright double star.  40 stars counted in the central area.  Another faint group following.  Decent cluster.
oc 6755:  15'; V. 7.5; Br.* 11:  An unusual cluster, and worth a look.  Ringed by brighter stars, there are three dense sections.  100x resolves most of the haze.  About 75 stars were counted.  Very nearby is oc 6756, which makes a good contrast with 6755.  This is a tiny, compressed and faint group.  Up to 300x was used to resolve it.
oc 6775:  13'; 10 *s:  A small, faint group of stars is noted in a busy field.  12 stars at 200x in a very small area.  20 more in a wider area.  Seen well at 150x.
oc Be 43:  5'; Br * 15:  6 very faint stars seen at 187x and 200x.  Sky conditions were not very good.
oc Do 35:  7'; asterism?:  125x is just high enough to block out star 31 from the field.  About 20 stars counted, including a faint, very close double noted just south of the 9.5 mag. star at the cluster's center.
oc King 25:  5':  Several tiny comites seen near a much brighter, white star.
oc Poole J1855.0+1047:  Just north following 6709.  Small, very dense knot of somewhat bright stars.  North of a bright triangle of stars that includes V 913.  15 stars counted at 250x.
gc Pal 11:  10'; V. 9.8:  Noted at low to medium power.  Large area of very, very faint stars in behind brighter ones.  Just south of a mag. 8.5 star, it reminded me of a large Be cluster.  Don't expect to see a "globular."
eg 6814:  3' x 2'.8:  V. 11.2; sb 13.4:  Easily spotted at 100x, large and round.  Central area bright and large, surrounded by fainter haze.  Very very faint in 6" scope.
eg 6821:  1'.1 x 1'.1:  V. 13.1; sb 13.1:  Spotted at 100x, round and faint, pretty large; best with averted vision.
pn 6772:  86"; V. 12.7:  Ghostly apparition spotted easily at 60x.  Up to 200x used.  Uniform shape and brightness (round).  Fun to view in the 12".
pn 6778:  37"; V. 12.3:  Less than half the size of 6772, though considerably brighter.  Noted well at 120x with sky glow filter.  375x used successfully.  Oval shape, with 2 bright knots.  Bright, distinct middle section and a small, much fainter outer area.
pn 6781:  114"; V. 11.4:  Huge and bold, I had great views of this object from 150x up to 200x.
Recommended.
pn 6790:  10"; V. 10.5:  Use a very good pinpoint atlas for these nearly stellar planetaries.
pn 6803:  10"; V. 11.4:  Again, nearly stellar.  Use high magnification and a filter.
pn 6804:  66"; V. 12; Central * 14.3:  Another minor showpiece!  Central star viewed at 187x, though much easier at 250x.  Another faint star on the very edge, making it harder to see the central one.
pn 6807:  8"  V. 12:  At 250x a tiny bit of bluish haze was noted, using the Skyglow Filter.
pn I. 4846:  11"; V. 11.9:  Confirmed at 250x with a filter.

CYGNUS
oc Be 56:  3'; Br * 16:  Left over from last summer, I finally found it.  A few very, very faint stars resolved in behind some faint foreground ones.  Not much to see in a 12".  In a very rich area for sweeping.

SAGITTARIUS
oc 6494--M 23:  25'; V. 5.5; Br * 10; 150 *s:  Looking good in any telescope, I had not studied M 23 in detail in many years, as it tends to get overshadowed by all those Messier nebulae around there.  A major showpiece in the 12", I found it looked its best at 83x, where it fully resolves.  There are nearly 100 brighter members, and nearly as many fainter ones.  It resembles a city at night as seen from an aircraft.  Chains of stars, strings, circlets, crescents and lines.  Fun!
gc 6440:  4'.4; V. 9.3; Br * 16.7:  Spotted with ease at 60x, this is a bright globular in a 12" with a very bright center and a large area of surrounding haze.  It seems to glow like a lamp, though no stars resolve.  The first of 21 globular clusters I will observe in Sagittarius.
pn 6445:  44"; V. 11.2:  One of the "Little Gem" nebulae, it was spotted at 60x, though it improved a lot with a filter.  Lies close to a 7.5 mag. star; there is also a very faint one just N.  The N end is brighter, too, as if a faint star were embedded.
oc 6507:  15'; V. 9.6; Br * 12:  It was not a very good night of seeing in the south when I observed this, and will take a second look on a better night.  Just north following M 23, it was spotted at 60x.  I noted a large sprinkling of  faint stars following WX, a variable star.  About 30 stars were counted tonight, and I used up to 187x.  I also looked at 100x with the aperture stopped down to 8".  The stars were very faint but resolved.

CASSIOPEIA
oc 1027:  15'; V. 6.7; Br * 9:  We have been up pretty late, and this autumn constellation is in prime position after about 2 am.  The cluster is lovely in the 12" at 60x, with a 7 mag. white star near the center, and a 9.7 mag. pair further out.  Large, fairly scattered.  100x gives an impressive view of about 60 stars, mostly white.  Much less impressive in the 6".
oc Be 65:  5':  Studied at 125x and 150x, 12-15 stars were resolved just north of a somewhat brighter group that has a dipper shape involved.
oc Cz 13:  4'; Mag. 10.4; Br * 12.8:  Spotted at 100x as a very faint cluster of tiny stars.  The group is still resolving at 200x and 250x.
Mapman Mike