Friday 12 August 2016

#99-Vulpecula: Deep Sky Adventures

2016 continues to be a banner year for my observing program.  Even if it were cloudy from now till December, I would still have completed one of the most successful years of observing I have ever had!  The July/August session that just ended saw me out at the club observatory 8 times, for a total of over 29 hours at the eyepiece.  This summer I managed to begin and complete my Vulpecula project.  That consisted of 14 NGC objects, 2 IC objects, and 5 objects from other catalogues, along with about 150 double stars.

The NGC breakdown is as follows: 7 open clusters, 2 planetary nebula, 2 galactic bright nebula, and three galaxies.  Both IC objects are bright nebula, and the 5 other objects were all open clusters.  In addition, I searched out and observed over 150 double stars (including triples and multiples).  In this report I will only discuss the deep sky objects, but be assured that there are many fine double stars to see also.  The vast number of doubles to seek out certainly helped me become more expert at star hopping, and I'm pretty certain I got to at least glimpse every part of this wonderful constellation.

Most people know Vulpecula through its famous Messier object, #27, the Dumbbell Nebula.  Beyond that they may know it as the location of the Coat Hanger cluster (Cr 399).  I hope readers will be encouraged to seek out all of the other wonders this rich area of sky provides.

oc 6723:  7'; 15*s:  It seems fitting that I began my observations in Vulpecula with this small, obscure cluster.  Observed first at 83x, it is a striking little group.  A triangle of bright stars precedes it; an 8.5 mag. star at the apex (furthest away from the cluster), and 9 and a 9.5 mag. star closer to the cluster.  On the preceding end of the cluster are two tiny stellar triangles, with their apexes (or apices, if you prefer) pointing to the clusters following end.  The northern-most small triangle's northern-most star is a tiny double star.  These two triangles give the cluster a unique appearance to this minor gem.  At low power about 10 brighter, easy to see stars are noted.  Everything resolves at 136x, with most members near the two triangles.  There are now about 15 easy to see stars, and perhaps 5 more that are very faint.  The cluster sits amidst a glorious star field.  This is worth a stop with an 8" scope or greater.  In Deb's 6" it could be viewed and studied, but it was not very impressive.
 http://www.astrophoton.com/images/N6793-1.jpg

oc Cr 399, "Coathanger:"  90'; Vis. mag. 3.6; 40*s; Br. * mag. 5.2:  Because of a direct connection to oc 6802, this cluster is discussed here, rather than below in "Other Objects".  This giant cluster (it's not a true cluster, but rather an asterism, or chance arrangement of stars) is perfect for our 4 1/4" Astroscan scope, but tonight it got the 12" treatment.  It almost fits into my 42x field of view, but not quite. At 60x it's fun to trace the dozen or so bright stars.  Most of them are white.  However, star 4, the most southerly one, is yellow.  The bright double star north preceding star 4 is a beautiful gold colour.  It's a rewarding area to sweep at low power.  Four double stars were observed within the boundaries of the cluster.  These are HJ 2871 (actually a triple), Stf 2523, Stf 2527, and Stf 2530.  Visiting this group is one of the highlights of the constellation.  It even looks pretty grand in Space Eye, my 2" refractor.
http://images.fineartamerica.com/images-medium-large/coathanger-star-cluster-celestial-image-co.jpg

oc 6800:  5'; 20 *s; Br. * mag. 10:  Dreyer says "cluster, very large, pretty rich, very little compressed, stars from 10th magnitude"Why, then, do modern sources like Uranometria give the size as 5'??  20' would be more appropriate.  The cluster appears as a roughly circular group of about 20 bright stars (mag. 10 and down), showing well at 60x.  At 100x and 136x, two small, dense knots of fainter stars appear, one each at the north end and the south.  Each knot is about 4'.  It is an interesting group, and fun to observe up to 187x.  The surrounding area is rich in field stars.
 http://cseligman.com/text/atlas/ngc68.htm#6802

oc 6802:  5'; Vis. mag. 8.8; Br. * mag. 14; 201 *s.  First of all, let me say that I love the fact that the guide to Uranometria says that there are 201 stars in the cluster, and not just 200!  Anyway, back in early July, 1992 I observed this cluster with my trusty Edmund 8" scope.  My notes from then say "It appeared like a large, faint galaxy.  169x showed some resolution..."  Though not that impressive in an 8", it is beautiful in a 12"!  Noticed at 60x, it is elongated N/S, barely resolving at this power.  It already looks amazing!  At 100x the north end is easier to resolve.  The center is more difficult, and the south end is still mostly haze.  136x gives good resolution all across the cluster.  It is a gorgeous object!  It sits midway between two pairs of wide double stars, but south of them.  Follow the east end of Cr 399 and you will come to it.  It can be glimpsed in the photo, above, in the upper left.  At 187x there is still some haze in the south.  250x gives a remarkable view, with full resolution.  A minor classic!  I also had an opportunity to view this cluster a few nights later in a good friend's 22" scope.  Absolutely beautiful!  Like looking at M 11!!
 http://astro-kooperation.com/wp-content/uploads/2012/06/ngc6802_A.jpg

gn 6813:  3' x 3'; Emission:  This tiny bit of haze surrounding a faint star is more in size like 1'.2 x 0'.9.  Lying in a rich and bright stellar field, the nebula is just south preceding a 9.5 mag. star.  Noted as suspicious at 60x, it appeared as a very small blob of haze surrounding a faint star.  136x gives a good view of a somewhat rectangular hazy patch.  Using averted vision and a Skyglow filter, the nebula brightens considerably.  Up to 375x was used (no filter), still giving satisfactory views.  A very faint star is just north.
http://www.astrophotos.net/images/nebula/ngc%206813-lrgb-f07.jpg
gn 6820:  40' x 30'; Emission Nebula:  This area reminds me a bit of the Rosette Nebula in Monoceros.  An open cluster lies at the center (see below), surrounded by wispy and faint nebula.  Though prominent in photos, visually there is little to see.  Using 60x and an O111 filter, some thinly spread haze is noted preceding the cluster.  The cluster itself appears devoid of an nebula.  My Skyglow filter actually showed the nebula somewhat better.
oc 6823:  7'; 79 *s;Br. * mag. 8:  Located at 60x, a few bright stars are prominent, and a hazy white background of unresolved ones.  100x and 136x show a bright group of 4 stars in the center, in a close diamond shape.  A bright pair of stars sits south of center.  The brightest star is on the north preceding edge, being a bit brighter than the central stars.  187x resolves almost 50 countable stars, though fainter ones are winking in and out.  A notable dark area is north of the cluster.  200x and 250x give detailed inside views.  The central quad star now has 6 members!  A really nice group in a 12" scope.
 http://www.lafterhall.com/atk16_sv102ed_ngc6820_ha_003.jpg
oc 6823 surrounded by gn 6820.  I tried really hard to see the dark cone, with no luck.

oc 6827:  4'; 30 *s; Br. * mag. 13:  Spotted at 136x between two bright stars, preceding it.  It is very small and very faint.  It is just a hazy patch with one star showing on the preceding end.  Viewed at 187x, 200x, and 250x, and 272x it is still mostly unresolved haze.  A few stars resolve at 250x and 272x.  This is a challenge to locate in the busy star field, and probably needs a 16" or greater to resolve fully.
 http://martingermano.com/Images/N6827lredsg.jpg

oc 6830:  6'; 82 *s; Br. * mag. 10:  This is quite a beautiful cluster at 60x and 100x, and especially at 136x.  There is a 4-star diamond shape at its heart.  The cluster is somewhat "+" shape at low power, reminding me of what a smaller town looks like from an airplane at night at 30,000'.  A curving line of stars connects the south and the preceding stars.
 http://www.univie.ac.at/webda/dss/ngc6830.png

pn 6842:  57"; Vis. mag. 13.1; Cent. * mag. 15.9:  I had to make several attempts with the 8" in years past (1991), before glimpsing this large but elusive object.  Even with a 12" it is not easy to locate, using Uranometria's pinpoint guide.  It is pretty large and pretty faint at 100x, though using the Skyglow filter and 120x gives a pretty good view.  It is round and ghostly gray.  Using 136x with the filter also gives good views, though a fellow astronomer, relatively new at the game,  had considerable difficulty seeing it.  272x showed it a bit oval in shape, with one edge indented.  A curious object, but seen well in a 12" scope.  I did not see the central star.
http://www.astrosurf.com/mcianci/images/NGC6842AO7.jpg

pn 6853, Messier 27, "Dumbbell Nebula:"  402";  Vis. mag. 7.4; Cent. * mag. 13.9:  With certain deep sky objects I have processing problems--call it sensory overload.  M 27 is the result of a star shedding its outer layers of gas.  Knowing this does not help with the incredible view provided by any modest telescope.  In a 12" at 136x and using an O111 filter, there are few words that come to mind.  Perhaps Benjamin Britten's 1st String Quartet, Op. 25, 3rd Movement entitled "Andante Calmo" says it best.  In a more mundane verbal description, it seems to float past like a giant interstellar grayish-green football.    The north end appears rounder than the south.  The N/S ends are very bright.  The E/W sides are much fainter, with the following end (east) seemingly cut off suddenly.  Without any filter, several stars seem to be embedded in the nebula, though not really.  The central star is, though, and should be easy in an 8" mirror or higher.  M 27 seems more like poetry to me, rather than an interstellar object of great force and violence.  Visible at higher powers in a 12" are many swirls, shadings, and other fascinating and unexpected details.  This nebula repays frequent revisits.  Even in Space Eye, my 2" refractor, this is a memorable object.  It is certainly the deep sky highlight of Vulpecula.
Messier 27, by RASC Windsor club member Ted Gervais.

oc 6885:  20':  Vis. Mag. 5.6; 34 *s; Br. * mag. 5.9:  Vulpecula Star 20, mag. 5.6, is at the heart of this large, loose NGC cluster.  At 60x the group features many bright stars, and the cluster is eye-catching.  A denser and fainter part of the cluster is on the north preceding end, and is called Collinder 416 (see below).  100x and 136x fills the eyepiece with bright stars, though my preferred view of this modestly rich cluster is at 83x.
 https://upload.wikimedia.org/wikipedia/commons/0/02/NGC_6885_large.png

eg 6971:  0'.9 x 0'.2; Vis. mag. 13.4; Sur. Br. mag. 11.4:  There are only five galaxies plotted on  Uranometria Chart 66, and this is the lone NGC one.  It was surprisingly easy to spot at 136x, lying within a triangle of fairly bright stars.  187x shows a nice slash, not too small.  250x and 272x both show a bright center.  This actually turned into a fun find!
 http://www.ngcicproject.org/dss/n/6/n6921.jpg 

oc 6940:  25'; Vis. mag. 6.3; 170 *s; Br. * mag. 11:  Every once in a while, using a 12" scope to observe the deep skies pays off in big dividends.  Even with an 8" back in 1991 this cluster was a jaw dropper.  Tonight it was a breathtaking showpiece, by far the finest cluster in Vulpecula.  Along with Messier 27 and Cr 399 it is that constellation's best deep sky object.  60s gave an amazing view,though 83x was even better!  There are seemingly countless brighter stars filling the field of view,  This is a huge cluster, too!  It contains 5 very bright stars, including the superb double star Stf 2698, located in the south end.  FG is a deep golden variable star that sits smack in the middle of the cluster.  An interesting tail of stars breaks away from the main group, following it.  At 136x, the cluster must be swept to be viewed in its entirety.  Despite being so tired at this point that I could barely stand (it was my 3rd long night of observing in a row!), this object revived me and gave me a lot to think about on my drive home afterwards.
 http://jthommes.com/Astro/images/NGC6940_ZSFRWO30_PS3.jpg

eg 7052:  2'.1 x 1'.1; Vis. mag. 12.2; Sfc. Br. 13.4:  This is a pretty amazing galaxy in a 12"!  Easily spotted at 60x, it is close to a bright star.  It is already oval and pretty large.  Views were good to very good at all powers up to 272x.  It is bright, very elongated, and always easy to view.  At 250x a 15 (?) mag. star sits between the galaxy and the brighter nearby star (10.5?).  The galaxy is unusually bright, and worth seeking.
http://www.ngcicproject.org/dss/n/7/n7052.jpg

oc 7080:  1'.8 x 1'.7; Vis. mag. 12.3; Sfc. Br. 13.4:  This was the final NGC object in Vulpecula, and the last thing I observed in my Vulpecula studies.  It was spotted at 100x.  At 136x and 187x it was very bright and easy to observe.  It was round, with a very bright middle.  Views are still good at 250x and 272x, where the shape became oval.
http://www.ngcicproject.org/dss/n/7/n7080.jpg

gn I. 4954:  3' x 3'; Reflection Nebula:  There are two small patches of nebulosity in and around
gn I. 4955)  the small open cluster Ro 4 (see below).  One patch is on the north preceding edge of the cluster, and appears to be involved with a faint star just north of it.  Views are good up to 250x.  The 2nd patch is even smaller and fainter, and is located in the southern area of the open cluster.  Both objects are pretty small, but easily noticed.
http://cseligman.com/text/atlas/ic49a.htm#ic4954, 55

Objects From Other Catalogues

oc Be 83:  2'; 20 *s; Br. * mag. 17:  A very faint, small hazy patch was detected preceding a group of r fairly bright stars, three in a line and one about the central star.  Nothing much else to see here.  Nothing could be seen of oc Be 52, an even fainter group.

oc Cr 416:  8'; Vis. mag. 8.1; 40 *s;  Within the boundaries of much larger NGC 6885, it is just north preceding the bright central star of that cluster (see image, above, with NGC oc 6885).  This group is condensed and more open to views at higher magnifications.  Part of a double cluster!

oc Cz 40:  4'; 30*s: Located between two stars, mag. 9 (south following) and mag. 9.5 (north preceding).  The cluster is mostly haze at moderate power, but a few stars resolve at 250x.  It's a bit tricky to located, but Uranometria is correct in its placement.  Good luck!

oc Cz 41:  8'; 30 *s:  Centered around a mag. 9.5 star, it lies 2 degrees south of oc 6830.  It is first seen as a cloud of faint stars.  Best viewed at 187x and 250x, there are 6 stars north of the brighter central star, which hampers our view of most of the fainter members in this area.  The cluster is fairly large and scattered, though not of primary interest to lovers of open clusters.  However, it is in a lovely star field.

oc Ro 2:  45'; 20 *s; Br. * mag. 7.1:  The center of this giant cluster, somewhere in size between M 6 and M 7, is a 7.1 mag. golden star.  Uranometria shows 9 scattered stars within the boundary.  42x shows the entire group quite well.  A main group of stars runs N/S, becoming more dense near the center, especially just preceding the gold star.  Another dense pocket is immediately north of this star.  60x also shows the cluster well.  It is pretty rich but scattered.  Worth a stop at low power, and located immediately north following the gn 6820/oc 6823 complex.

oc Ro 4:  6'; 30 *s: The most interesting aspect of this little cluster in the presence of two puffs of bright nebula, I. 4954 and 4955 (see above). The cluster itself consists of about 15 brighter stars and several that are much fainter.  Views are good from about 136x to 150x.  See image under the IC discussion, above. 

Clear skies!
Mapman Mike