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classic dso equipment eyepieces LP observing observing report refractor sketching
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#326 Vondragonnoggin

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Posted 14 February 2019 - 06:53 AM

Allan, I agree with your philosophy on separation completely. Users can visit the EAA forum for equipment info as it is readily available there. I have removed my posts on equipment as I really feel it detracts from this thread which, as you stated, concentrates on Observing.

 

Much appreciation for using an extended toolkit in your observations though. Having an abundance of observational data by knowledgeable members here puts a big weight behind acceptance of that extended toolkit as a useful means of data collection.

 

I have a wealth of new targets to try and match observations on now!

 

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#327 AllanDystrup

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Posted 01 March 2019 - 04:24 AM

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The Crimson Pirate

 

     In this previous post I tried to observe the Gum-8 Bubble (Sh2-310) close to Tau-CMa, -- but I did not succeed: https://www.cloudyni...ield/?p=9144117.

 

     This past night I tried again, -- ahh but but still "no cigar"... On the other hand, I made a good observation of the largest known star in our Milky Way: the crimson hypergiant VY-CMa, so I thought I'd share that with you instead.

 

     This Crimson Pirate is sailing in the southern seas as seen here from Denmark; I caught him tonight at 6dg Alt. towards the SE horizon, cruising between the trees, aerials and chimneys:

 

VY CMa 01.jpg

VY CMa 02.jpg
*click*
[as usual: N is up and W to the right]

      -- Allan


Edited by AllanDystrup, 01 March 2019 - 04:46 AM.

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#328 AllanDystrup

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Posted 02 March 2019 - 01:06 AM

.    

A charm of powerful trouble --
Spring galaxy Sheets, Spurs and the Leo-I & Leo-II groups.

    

    

     As spring advances, my plan is to get some wide field views of the (relatively) close by galaxies in our Local Supercluster. As you know, the basic elements of the cosmic large-scale structures are galaxy clusters (knots), which are pushed out by areas of void into structures of walls/sheets and filaments. In our own galactic neighborhood, the Local Sheet defines the equatorial band of the Super Galactic Coordinate system (SGC), stretching on the night sky from UMa in the N through CVn, Coma and Virgo, further down S to Centaurus.

 

     The Leo Spur is the nearest distinct large-scale structure outside the Local Sheet. For an overview I refer you to this previous post on: Step 2 (6 Mpc ~ 20 Mly) : The Local Supercluster (https://www.cloudyni...ield/?p=8509435).

 

 

Local Sheet.jpg
*click*

 

     In the Local Supercluster reference frame, the Virgo Cluster is practically at rest, while the galaxies in the Local Sheet are being pushed down from the Local Void above the Supergalactic plane (Cyg-Her on the night sky), streaming towards the Virgo attractor; At the same time the galaxies in the Leo Spur at the border of the Virgo infall zone are being weakly attracted to Virgo and also being pushed upward by the Gemini-Leo Void (Tau-Gem to Mon-Leo on the night sky) below the Supergalactic plane:

 

LocalSheet-LeoSpur'.jpg

*click*

 

To-Be-Continued...

     -- Allan


Edited by AllanDystrup, 02 March 2019 - 01:31 AM.

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#329 AllanDystrup

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Posted 02 March 2019 - 01:10 AM

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Leo Spur, LEO-I Galaxy Group
“Leo Triplet – East”: M66 – M65 – NGC3628

    

    

     It’s an early morning on the last day of winter (2019-02-28, 01:30 CEST, UT+2). It’s unseasonably warm for this time of year here past midnight (5⁰C, 90% Hum. with the DewPt at 3⁰C), and we’ve had temperatures over 20⁰C in late February this year, – a winter record for the country! The 23-day (34%) moon is in Sagittarius well below the SE horizon, --which is great, but the observing conditions are only so-so due to high cirrus, and the forecast says increasing low stratocumulus in a couple of hours, so I must be on my way... (Trsp.: 1-3/7, Seeing 5-6/10, LP.: SQM ~17 / NELM 5).

    

     I’ll start my spring galaxy wide-field observations with a look at the galaxy groups in the Leo Spur below the Supergalactic Equator:

     LeoSpur.jpg
*click*

    

     Using NV on my small 60mm finder scope (7x in a 5½⁰ FOV), the three main galaxies in the Eastern Leo Triplet (M65, M66 and N3628) are seen as a group of “faint fuzzies”, just E of the “sitting man” asterism S of Theta Leonis. The central bulge and main orientation of the galaxies can be glimpsed, but no further details are visible.

 

Leo-I Triplet-E.jpg

*click*
 

     Zooming in on the two Messier galaxies (21x in 2⁰ FOV), I start to see some details: the central core and almost N-S oriented ellipse of tightly wound spiral arms of M65, and the bright nucleus of M66, that is embedded in spiral arms forming a warped NE-SW oriented envelope. The reason for the warping of M66 is of course close encounters with the NGC 3628 “Hamburger galaxy", as is revealed by the distribution of neutral hydrogen in the intergalactic space of the galaxy group:

 

Leo-I Triplet-E IGM.jpg
*click*

 

To-Be-Continued...
     -- Allan


Edited by AllanDystrup, 02 March 2019 - 01:43 AM.

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#330 AllanDystrup

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Posted 03 March 2019 - 02:16 AM

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Leo Spur, LEO-I Galaxy Group
“Leo Triplet – West”: M96 – M95 – M105 - (NGC3384)

 

    

     Tonight is the first night of spring (2019-03-01, 20:30 CEST UT+1), and I've set up my classic 4” refractor with a 41mm wide field eyepiece for 17x magnification in a 2½⁰ FOV.  The temp. and dew.pt. are both down at 2⁰C, and falling, so with a humidity of 100%, there’ll soon be an icy coating on the dew shield of my telescope; So long as the objective and eyepieces are not dewing up though, I’m fine. The moon is down, transparency is medium, the seeing is above medium, and the LP is controlled at 5.7 NELM. I’m good to go!

jump.gif 

    

    The Messier galaxies M96-M95-M105 (also known as the Western Leo Triplet) are located together with N3384 plus 36 fainter galaxies in the M96 galaxy group. The M66 (E Triplet) plus the M96 (W Triplet) groups are then aggregated in the Leo-I association, located in the foreground at 10 Mpc (~33 Mly) in the Leo Spur of galaxies.

    

      I find the easiest way to frame the M96 galaxy group is to start from the ”foot” of the Sitting Man asterism below θ Leonis, and then just pan the telescope ~8⁰ due W, till I have the M96-M95 galaxy pair in the FOV. Looking through an NVD with a red longpass filter, I can easily see M95 as a round “faint fuzzy”, and M96 with a brighter stellar core in a faint tight envelope of galaxy arms, tilted a bit SE-NW. In the NE part of the field, the pair of bright elliptical galaxies M105-N3384 (=N3371!) are also clearly seen: M105 larger and round, while N3384 somewhat fainter, slightly elongated and slanting a bit towards NE.

    

Leo-Triplet-W.jpg
*click*

    
     As described in the previous post, there’s a large ring of intergalactic neutral (HI) gas surrounding the M105-NGC3384 galaxy pair, possibly an expanding density wave of stripped gas from a head on collision of two primordial spiral galaxies, merging and leaving the two ellipticals (M105 + NGC3384) near the center of this Leo Ring. Currently M96 is drawing a tidal plume from the Leo Ring, accreting gas onto its warped outer disk.

    

Leo-Ring.jpg

 

To-be-continued...

     -- Allan

    


Edited by AllanDystrup, 03 March 2019 - 02:30 AM.

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#331 AllanDystrup

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Posted 04 March 2019 - 01:30 AM

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Leo Spur, LEO-II Galaxy Group
“Leo Cloud” N3607 Group:   N3607 – N3608 – N3626

    

    

     Having observed the M66 and M96 galaxy groups at 10 Mpc (33 Mly) distance in the Leo-I association, I now pan my 4” refractor 9⁰ NE to a position right between δ and θ Leonis. This opens a window to a much more distant group of galaxies: the Leo Cloud aka the Leo-II association at 22 Mpc (73 Mly).

    

     Leo-II-Map.jpg
*click*

    
     The 3 brightest of the 19 galaxies in the N3607-group of the Leo Cloud are easily seen at 17x in the 2½⁰ wide field view of my 4” classic refractor: close together are the N3607-N3608 pair of lenticular galaxies, while 45’ up NE from N3607 we find the tight Sa spiral N3626. Two fainter galaxies can also be glimpsed in the field: N3605 plus N3599.

 

N3607-Group  LEO-II.jpg
*click*

    
     The pair of lenticulars N3607-3608 are closely gravitationally bound (in the group PGC 34426), together with the Sa spiral N3626, all at ~22 Mpc distance [SGY]. N3505 and N3599 are a bit closer at ~19 Mpc [SGY], but whereas N3599 is still in the PC 34426 group, N3505 is just beyond the infall region of N3607-3608, and is thus in its own one-galaxy-group (PGC 34415) in the Leo Cloud.

    
     The NGC 3626 (aka NGC 3632) btw is an interesting “multispin” galaxy with counter-rotating molecular gas, possibly from a recent merger with an intergalactic cloud of neutral hydrogen (Patrick Moore included this member of the Leo Cloud in his Caldwell list as: C40). This morphology cannot of course be studied with direct or averted vision, -- you must use the refined knowledge and imagination of your inner “third eye” …

 

 

     Here's an overview of the Leo galaxies I have studied wide field the past couple of nights:

 

LeoSpur-Map.jpg

LeoSpur-Lists.jpg
*click*

 

     -- Allan


Edited by AllanDystrup, 04 March 2019 - 01:33 AM.

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#332 AllanDystrup

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Posted 06 March 2019 - 02:19 AM

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The Local Sheet of Galaxies
(Supergalactic Equator)

    

     I’ve now had look at the galaxies in the Leo Spur below the Supergalactic plane, which is preceding the Local Sheet that defines the equatorial plane of the Supergalactic Coordinate System on the night sky.

 

     The Local Sheet stretches as a “Spring Milky Way of galaxies” from north to south on the night sky, encompassing both close by (~5 Mpc) galaxy groups such as the M81/82 Group in UMa, the CVn-I Group in Canes Venatici and the M83 Group in Centaurus, but also in the background more distant (~15 Mpc) galaxy groups such as the M108/109 UMa Group, the Coma and Virgo galaxy clusters plus the remote Centaurus Cluster (A3526). Our own Local Group of galaxies with the large Milky Way and the Andromeda spirals with their associated satellites and dwarf galaxies (diameter ~3 Mpc) is also a member of the Local Sheet, located per definition at origo (coordinate 0,0,0) in the SG reference frame.

 

     On a wider scale, the Local Sheet and the Leo Spur are both central members of the larger Local Supercluster, which reaches out to ~40 Mpc, and has the Virgo Cluster as the major group in the structure. The region of gravitational attraction for the Virgo Cluster is easily seen on a plot of cosmic galaxy flows as defined by back-tracing the peculiar radial velocities of the galaxies:

    

Local Sheet.jpg
*click*

 

     I’d like to get some wide-field views now of the galaxy groups in the Local Sheet, along the Supergalactic equatorial plane. I’ll start with the main attractor: the Virgo Cluster:

 

The Virgo Cluster.jpg
*click*

 

Now just for some clear skies...

     -- Allan

 


Edited by AllanDystrup, 06 March 2019 - 03:37 AM.

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#333 AllanDystrup

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Posted 11 March 2019 - 06:22 AM

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The Virgo A Cluster
M86-M84 subgroup, with Markarian’s chain.

 

 

     It’s closing in on midnight here in the start of March (2019.03.10, 23:30 CEST, UT+1). A row of low-pressure cyclones has swept from the N. Atlantic across Scandinavia the past weeks, dragging along endless showers of rain and sleet, but tonight there’s a transition between two of them. The weather has suddenly cleared up nicely, with a fresh temperature of -2⁰C and a humidity of 84% (Dew.Pt. -4⁰C). Both transparency (5/7) and seeing (8/10) are well above medium, and the 18% / 4.7day Moon is out of the way below the NW horizon, yielding a bright suburban night sky with a NELM of 5.8 (SQM 19.5). I’m ready to start my wide-field survey of the Virgo Cluster! smile.gif

    

    

     As mentioned previously, the Virgo Cluster is composed of ~2000 galaxies located in three distinct substructures, each centered on old massive “early” spherical/elliptical systems:

  • Virgo A: M87 E0-1 plus M86 E3 - M84 E1, the largest subgroup that also includes:
    M89 E0, M84 E1 - M85 S0,  and the spirals M58 SBb, M88 Sb - M91 SBb, M90 SBab, M100 SBbc.

     
  • Virgo B, M49 E2
     
  • Virgo C, or E: East: 60 E1, including M59 E5
     

     The 3 large Virgo subclusters are surrounded by smaller clouds of mostly “late” spiral galaxies, known as the S: South Cloud (N4636 E, M61 SBbc), N: North Cloud (around M98 SBb - M99 Sc), and LVC: Low Velocity Cloud (around NGC 4216). All Virgo subclusters and clouds are in the process of merging and will eventually form one single vast cluster.

 

     Besides these substructures in the Virgo Cluster proper, there are several distinct galaxy groups (M towards the NE, W-W’ towards the SW) which are currently in the far background as observed from our Milky Way galaxy but are streaming together with the Virgo Association and our whole Local Sheet towards the Great Attractor in Centaurus.
 

     Virgo Subclusters.jpg
*click*
    

     

     My first target tonight is the galaxies in the M86/84 subgroup of the Virgo A cluster.  The two giant elliptical/lenticular Messier galaxies dominate this subgroup, that also includes a string of old massive elliptical/lenticular members stretching out from M86 to the E and further up N: Markarian's Chain. 

 


Virgo A M86-84 B.jpg
Virgo A M86-84 W.jpg
[as always N: is up, and W is right]
*click*

    

     M86 is the main local gravitational attractor, and it is surrounded by several smaller spiral galaxies, including the pair NGC 4435-38 (“The Eyes”) and NGC 4402.  The constellation of galaxies around M86 is especially interesting because it shows clear evidence of interaction between the massive elliptical M86 “mothership” and the surrounding smaller spiral satellites.  Already in my small 60mm finder scope I can see the NNE-SSW elongation of the N4438 spiral in “The Eyes”, and with averted imagination I can also glimpse the warping of the disk caused by a recent collision with M86 – marvelous!

 

Virgo A M86-84 Zoom-In.jpg
*click*

 

      -- Allan


Edited by AllanDystrup, 11 March 2019 - 06:49 AM.

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#334 AllanDystrup

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Posted 11 March 2019 - 09:11 AM

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Virgo A Cluster
Wide Field

    

     And to place the M86/84 galaxy subgroup in context, here's a wide field view of the central Messier galaxies in Virgo A, still using my 60mm finder but with a 41mm eyepiece + the PVS14 IIT -- quite an overwhelming sight being able to frame most of the central Virgo A group in one field of view smile.gif :

    

Virgo-A WF B.jpg

Virgo-A WF W.jpg
*click*

    

     -- Allan

 


Edited by AllanDystrup, 11 March 2019 - 09:16 AM.


#335 Jeff Morgan

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Posted 11 March 2019 - 09:39 AM

  On a wider scale, the Local Sheet and the Leo Spur are both central members of the larger Local Supercluster, which reaches out to ~40 Mpc, and has the Virgo Cluster as the major group in the structure. The region of gravitational attraction for the Virgo Cluster is easily seen on a plot of cosmic galaxy flows as defined by back-tracing the peculiar radial velocities of the galaxies:

    

attachicon.gif Local Sheet.jpg
*click*

 

  

 

The backtrace pattern is very interesting, Looks like field lines and reminds me of an old article from Sky & Telescope, mid 90's on Plasma Cosmology.


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#336 AllanDystrup

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Posted 12 March 2019 - 07:35 AM

Jeff,

 

     Yes indeed, cosmography of the local universe is developing fast these years, -- here are a couple of refs. to recent discoveries in this area:

 

https://arxiv.org/abs/1710.08935

http://irfu.cea.fr/laniakea
https://www.youtube....h?v=1mQr6mzmzbU

 

--- oOo --- 

    

     I was out this early morning for some follow-up studies of the Virgo A subgroup, using my 4" refractor; Here's a couple of views of the base of Markarian's Chain of galaxies, which I find esp. interesting due to the backbone of evolved ellipticals with an entourage of younger, infalling spirals:

 

Markarian-Base 01.jpg

Markarian-Base 02.jpg
*click*

    

     -- Allan

 

 


Edited by AllanDystrup, 12 March 2019 - 07:39 AM.

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#337 AllanDystrup

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Posted 13 March 2019 - 06:13 AM

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M 87
The Mothership

   

    

     From the M86/M84 subgroup in the Virgo A sub-cluster, I now pan my telescope a good 1⁰ SE where I find the gravitational center of the Virgo A sub-cluster, the Virgo cluster at large, and indeed of our whole local Super Cluster:  the supergiant elliptical galaxy Messier 87

    

M87-16x.jpg
*click*

 

     This galaxy is a spheroid ball with a total mass ~200x the Milky Way and a supermassive black hole of ~7 x 109 solar masses in the center.  In my telescope, M87 looks like a peaceful, perfectly round fuzzball with a bright center gradually fading out to a dim halo, -- but the center is an active galactic nucleus that is sucking ionized gas into an accretion disc, rotating at 1000 km/s and shooting out a pair of 5000 light years long light sabers in the shape of two jets of electrons spinning along the magnetic poles of the singularity, while strongly radiating in the high energetic gamma, X-ray and radio parts of the spectrum.

 

M87-Inf.jpg
*click*

 

     I looked for traces of the jet, but was not able to see it (position marked on my snapshot above). I’ll try again later with a higher magnification.

 

     -- Allan


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#338 AllanDystrup

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Posted 14 March 2019 - 06:55 AM

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The Butterfly,
and other tales...

 

     
     From M87 at the center of the Virgo A subgroup, I now pan my 4” refractor a further 2⁰ ESE, where I first encounter the large barred spiral galaxy M58 at the E border of the Virgo A subgroup, and then, continuing another 1⁰ ESE, I hit upon the pair of large ellipticals: M59 and M60 at the center of the Virgo C (or E:Eastern) subcluster. My normal route to the Virgo C subcluster btw. would be from the “Lambda Asterism” SW of 34 Vir (this being my main anchor for galaxy hopping in Virgo), but tonight I'm sailing in from the west....

    

    

     M58 is an “anemic” galaxy deficient in hydrogen gas due to passing through the dense inter-cluster medium. Close to M58 (a good ½⁰ SW), I can spot the pair of unbarred SA spiral galaxies NGC 4567 + 4568, that is in the early phase of colliding and merging, as revealed by shock compression of the gas and dust into a filament of molecular clouds between the galaxies, and also by the induced star formation in the areas bordering the overlapping galaxy parts. The colliding “Siamese Twins” (N4467/68) form an interesting butterfly shape, that is easily seen in my small refractor... Wonderful!

         

Virgo A-C Butterfly.jpg

SiameseTwins.jpg
*click*

    

      M60 and M59 are both giant elliptical galaxies at the center of the Virgo C sub-cluster. M60 is in the process of gobbling up a much smaller spiral galaxy: N4647, which I can just glimpse NW of M60 in a wide field view of the area.  The M60-N4647 pair is also known as Arp 116. I'll need to take a closer look at this pair at a higher magnification...

    

Virgo C.jpg

*click*

    

     -- Allan


Edited by AllanDystrup, 14 March 2019 - 07:03 AM.

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#339 AllanDystrup

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Posted 25 March 2019 - 06:48 AM

.

Messier M49
(NGC 4472)

    

    

     It’s two hours past midnight in the middle of March (2019-03-19, 02:00 CEST, UT+1) and I’m out with my small 60/360mm finder scope.  The conditions for DSO this early morning are unfortunately quite bad, with a 93% moon close by in Leo, combined with a transparency of only ~3/7 due to condensing high humidity and rags of low, drifting clouds.

    
     My main target tonight is M83 (the Southern Pinwheel galaxy), but with a culmination height of only 4⁰20' Alt. here from 56⁰ N in Copenhagen, the NELM towards the horizon is abominable, and so I can *just* barely spot this object (observation described here: https://www.cloudyni...sier/?p=9236376)

    

    
     Instead I decide to have a wide field view of the Virgo B subcluster, with the giant elliptical galaxy M49 at its center. This part of the Virgo cluster is found ca. 5⁰ S of the major subcluster Virgo A, centered on the other giant elliptical M87.

    


Virgo B - M49 Inf.jpg
*click*
    

     As seen in my small 2” finder scope, M49 shows up as a round, well-defined nebula with a brighter central nucleus, and a 12½m star close by to the E:

 

Virgo B - M49 Obs.jpg
*click*

    

    
     High resolution images of M49 reveal a fleet of surrounding dwarf galaxies plus a swarm of ~6000 globular clusters, all caught in the gravitational web of this huge galaxy spider. M49 is currently interacting with the UGC7636 dwarf close by to the SE (=ARP 134), and it has probably previously gobbled up several similar dwarf galaxies, as is indicated by the bimodal distribution in metallicity of its GC population (a byproduct of mergers). I’ve indicated the position of the 14½m dwarf companion N4467 on the snapshot above, though I didn’t see this companion with certainty; I did however spot a couple of other small galaxies in the Virgo B group: the E3 elliptical N4464 and the SA spiral N4492.

 

     -- Allan


Edited by AllanDystrup, 25 March 2019 - 06:54 AM.

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#340 AllanDystrup

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Posted 26 March 2019 - 06:16 AM

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Virgo A-B-C
Closer up

    
     It is close to midnight in the end of March (2019-03-25, 23:30 CEST, UT+1). A weak high pressure has settled over Ireland, guiding cool polar air from the N past the Norwegian mountainsides and down over Denmark, resulting in an exceptionally calm and clear night. The temp. is a fresh and cool 2⁰C, with a humidity of 87%, and the dewpoint is close by at 0⁰C. Both seeing (8-9/10) and transparency (5-6/7) are way above medium, and with the 71% (21dy) Moon tucked well away at the horizon towards the SE, the LP is a respectable suburban value of NELM 5.8 (SQM 19.6) at zenith.

    
     This will be a great spring night for deep sky studies, so I start setting up my 4” f/6.4 refractor to have a closer look at the major giant elliptical galaxies in the Virgo A, B and C subgroups, which I have observed previously in extreme “wide field mode”, using my small 2” f/6 finder scope (as described in the posts above). I start from the lambda asterism around Rho Virginis, then pan the refractor straight up 1½⁰ due N in DEC, where I immediately spot the two giant elliptical galaxies M59 and M60 in the Virgo-C (eastern) subcluster. At 30x magnification, these galaxies show up as faint fuzzies when I observe them using “glass only”.

    
     For a better view that blocks out the suburban LP and enhances the contrast, I now add a red longpass filter plus my image intensifier monocular. The colliding galaxy pair NGC 4649 (M60) + 4647 (= Arp 116) is now clearly seen, and other galaxies also start to pop up in the field, notably: N4638 (edge on S0 lenticular), N4606 (Sa spiral) and N4641 (S0 lenticular). Wonderful to get an impression of the Virgo C subcluster with these smaller galaxies swarming around the two giant Messier ellipticals in the ~1½⁰ FOV!

    

M60-59 Obs.jpg
*click*

    

To-be-continued...

     -- Allan


Edited by AllanDystrup, 27 March 2019 - 01:41 AM.

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#341 AllanDystrup

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Posted 27 March 2019 - 03:41 AM

.

     Virgo A

M58 & the Twins

 

     It’s now just past midnight, as I gently sweep my 4” refractor from the M60-59 giant elliptical pair, 1½⁰ due W in RA, where I get the eastern part of the Virgo A subcluster in the field, with M58 towards the NE and the “Siamese Twins” towards the SW.

     

     In the 13mm Ethos eyepiece (50x @ 40’ FOV), the M58 SAB spiral shows up as a bright elongated nucleus (the core + short bar) with an obvious NE-SW orientation, embedded in a fainter halo of the two spiral arms (which I cannot distinguish).

    

     The pair of colliding SA unbarred spirals NGC4567/68 (the “Siamese Twin”) are beautifully seen, both with a bright nucleus surrounded by a fainter haze of the unresolved spiral arms; The eastern ends of the twin galaxies are clearly overlapping in their silent slow-motion collision, -- what a marvelous sight!

    

Virgo A cu.jpg
*click*    

 

To-Be-Continued...

----- Allan


Edited by AllanDystrup, 28 March 2019 - 03:31 AM.


#342 AllanDystrup

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Posted 28 March 2019 - 03:01 AM

.

Virgo B
M49 and companions

 

     One way to galaxy hop from M58 to Virgo B is panning the scope a good 2⁰ W in RA to M87, then straight S 4½⁰ in DEC to M49; So that’s what I do now, when I’ve finished observing the NGC4567/68 spiral pair flapping their cosmic butterfly wings.

    
     The giant galaxy M49 (NGC 4472) is seen in my 4” refractor as a very bright elliptical core in a gradually fading, outer halo. I look for the irregular dwarf galaxy UGC 7636 SE of M49, but I am not able to detect it (I’ve marked its position on my snapshot). Research has discovered a bridge of neutral hydrogen with a HII region being pulled from the dwarf galaxy towards M49, -- a result of ram pressure stripping. (The pair M49-UGC7636 is also known as ARP134).

    
     As with the giant elliptical galaxies in other Virgo Subgroups, M49 is surrounded by several other smaller galaxies in Virgo B, the brightest being a couple of ellipticals: N4488 (lenticular SB0) and N4464 (E3) plus a couple of SA spirals N4492 and N4470. These are clearly seen in my 4” scope, while other fainter cluster members are at the limit of resolution tonight. Still a very satisfying wide field view of Virgo B!

 

Virgo B cu.jpg
*click*

 

To-be-continued...

     -- Allan

 

PS:
The Lenticular galaxy N4488 has an interesting warped shape, probably from gravitational interaction with another galaxy; I looked for this in my observation, -- but failed to detect it with certainty:

 

N4488.jpg


Edited by AllanDystrup, 28 March 2019 - 03:36 AM.


#343 AllanDystrup

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Posted 29 March 2019 - 05:19 AM

.

M87 (NGC 4486)

Well it's Saturday night / You're all dressed up in blue
I been watching you awhile / Maybe you been watching me too...

    

    
     I’ll end this wide field sweep of the Virgo Cluster with a closer up view of the mothership at the gravitational center of this galaxy group: the supergiant elliptical M87. With a density of 2.7 trillion solar masses (more than 4½x the Milky Way) it’s quite possible that, when we’re watching it here from our galaxy, we are at the same time being watched from up there too...

    
     At the heart of M87 is a 3.5 billion solar mass black hole, with an accretion discs that shoots out a gigantic jet of hot plasma. The jet extends >1.5 Kpc (4.9 Kly) from the galaxy core and glows with the optical blue light of electron synchrotron radiation as well as in the radio and X-ray spectrum (the Virgo A radio source, and Virgo X-1, respectively).

    

     M87 (N4486 is surrounded my many satellite galaxies, including a close pair of dwarfs (UGC 7652 1 and 2) as well as several larger elliptical/lenticular galaxies, notably: N4478 (E2), N4476 (SA0) plus N4486 a and b.

         

    

M87 cu.png
*click*

    
     I did look for the jet as well as the close by UGC dwarfs (not to be confused with the jet) – but I was not able to detect either of these (their position marked on the snapshot above). Oh yes, M87 is definitely way tougher than the rest...  cool.gif

 

     -- Allan


Edited by AllanDystrup, 29 March 2019 - 05:27 AM.


#344 AllanDystrup

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Posted 31 March 2019 - 08:46 AM

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“Powerful you have become, the dark side I sense in you.” (- Yoda)
M87 – The Jet

    

    
     It’s the end of March, closing in on midnight (2019-03-29, 23:00). The temperature is a comfortable 6⁰C, with a medium humidity (84%) and DewPt (4⁰C). The 34% (24 dy) Moon is way down -40⁰ Alt below the horizon, so the LP is a controlled NELM 5.6 (SQM 19) suburban. All set for my quest tonight: the M87 Jet.

    
     I have brought out my Vixen FL-80S f/8 refractor, and have zoomed in on M87 with my Zeiss O-10mm eyepiece (108x, 0.4⁰ FOV); With glass only, the giant elliptical galaxy is seen as a relatively bright and round nebulous spot, like a mottled fuzzball, reminiscent of a globular cluster (much as described in my obs report here: https://www.cloudyni...sier/?p=7170052).

    
     For more detail, I now switch to live video using my R2 ccd/lcd, yielding approximately the same magnification (110x in ½⁰ FOV) as the Zeiss O-10mm, but with improved brightness and contrast. Both seeing and transparency tonight are just above medium (6-7/10 & 4-5/7 respectively), and a light wind and high atmospheric haze do limit the resolution somewhat. In moments of good seeing, I am however able to spot the jet shooting like a Jedi lightsaber out NW from the "dark side": the powerful central supermassive black hole in the giant elliptical galaxy core. WOW!

    

    

M87 lightsaber.png
*click*

    
     I remember that Rod Mollise wrote somewhere on his Astro Blog that traditional glass eyepiece observation of the M87 jet in his experience requires a 20” or larger scope under dark skies, -- but also that he had caught the jet using his C8 scope with a Stellacam-II and a 10s exposure under suburban skies. So not bad I think, glimpsing the jet live video with my 3” refractor + an entry level R2 video cam. smile.gif 

 

     -- Allan


Edited by AllanDystrup, 31 March 2019 - 09:49 AM.


#345 AllanDystrup

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Posted 04 April 2019 - 12:50 AM

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M81 Galaxy Group.

     
     I'm moving on now in my project viewing the Spring Milky Way groups of galaxies in a wide field setup. I started with the galaxies at the deep gravitational well of the Virgo Supercluster (~15 Mpc - 50 Mly distance), and before that, I observed the infalling galaxy associations Leo-I (10 Mpc – 33 Mly) and Leo-II (22 Mpc – 73 Mly) in the Leo Spur of galaxies, preceding the Local Sheet on our night sky.

    
     Tonight, I’d like to focus on the nearby galaxy groups in our own Local Supercluster, much closer by (~5 Mpc - 15 Mly), starting from the north with the M81 Group in UMa, then moving south to the M101 and the CVn-I Galaxy Groups in Canes Venatici, and finally ending up deep south with the M83 Group in Hydra. Being ~3x closer to our Milky Way than the Virgo Attractor, the galaxies in these local groups show up more widely scattered on the night sky, but they also offer greater detail in structure as compared to the more distant galaxy groups.

    

    
     So tonight is 2019-04-01, 23:00 CEST DST UT+2, i.e. the first night in April this year, and we have moved from normal astronomical time to summer time (aka DST: “Daylight Saving Time”). The temp. is a fresh and cool 2⁰C, the humidity is relatively low ~78%, and the DewPt is down at -2⁰C. The 11% - 26dy Moon is buried way down 48⁰ below the N horizon, so the LP is quite good for my suburban backyard (NELM 5.8 - SQM 19.6). We’re still in the wake of a weak high pressure, guiding clear polar air down over Denmark, resulting in another exceptionally transparent (5-6/7) and calm night (seeing 8-9/10). Such perfect DSO nights are rare at our latitudes, but hey! -- here is one waytogo.gif

 

     The Great Bear (UMa) is culminating right at this time in the late evening, jumping so to speak over the Lion (Leo) directly towards the South.  In fact, Merak (Beta Uma) is passing close to Zenith right now, so observation of the M81 Group does not get better than this for my 56⁰N latitude. (I’m happy though for my 90⁰ Zeiss Amici diagonal, without which observations in UMa tonight would be quite neck straining...). Well then, better get on with it!

    
     I point my 4” refractor with a 41mm ETH eyepiece towards M81, the largest galaxy in the group. The M81 Group counts 41 members, including 4 NGCs: 3031 (M81), 3034 (M82), 3077 and 2976. The two large Messier galaxies (M81-M82) are clearly seen using glass only, and the main structure of both galaxies can be glimpsed with AV. With my image intensifier on top of the 41-ETH, all four mentioned NGC galaxies can now be studied in greater detail (though I can only frame 3 galaxies in the 2⁰ FOV @ 15x magnification).

    

M81-82-N3077 TV41PAN.png
*click*

To-be-continued...

     -- Allan


Edited by AllanDystrup, 04 April 2019 - 07:25 AM.

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#346 AllanDystrup

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Posted 04 April 2019 - 01:12 AM

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M81 Group -- continued.

         

M81-M82 TV21ETH.jpg
*click*

         

     M81 (NGC 3031 aka Bode's Galaxy) is a SA spiral with a bulge that is significantly larger than the one found in our Milky Way. The bulge has an active galactic nucleus (AGN) with a supermassive black hole ~15x the mass of the black hole in our Milky Way. M81 is surrounded by two prominent spiral arms with large quantities of dust as well as starburst regions. Observing M81, the large central bulge is evident, and already at 15x I can glimpse the pair of closely wound spiral arms. At higher resolution some small H-II regions should be visible in the spiral arms (position indicated on my snapshot), but I’m not able to spot these with the 610nm longpass; Maybe I’ll try later with a 12nm Hα filter, but my guess is I’ll need more aperture than my 4” for this. (A better option will probably be to do a live video observation of this object).

    

M81-M82 TV13ETH.jpg
*click*

    

    
     Gravitational interactions of M81 with the smaller, surrounding NGCs in the group have stripped hydrogen gas from all galaxies into gaseous filamentary structures in the group. Some of this gas has subsequently fallen into the centers of M82 and NGC 3077, leading to vigorous starburst in these companions. M82 (NGC 3034 aka the Cigar Galaxy) has been classified as an I0 irregular, and I can see the bright starburst core divided in two by dark gas and dust filaments. Recent research has however shown M82 to be a nearly edge-on spiral galaxy with a bright central bar plus two spiral arms that both have a bright starburst knot at the point where they emerge from the bar; Looking for this morphology, I can indeed identify the bar plus the two knots where the arms connect to the bar, all embedded in the fainter glow of the pair of closely wrapped spiral arms. Interesting!

    

     --Allan


Edited by AllanDystrup, 04 April 2019 - 07:26 AM.

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#347 AllanDystrup

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Posted 04 April 2019 - 07:38 AM

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NGC 3077

    

    

N3077 TV13ETH.png
*click*

 

     -- Allan


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#348 AllanDystrup

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Posted 07 April 2019 - 06:55 AM

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The M101 Galaxy Group

    

    
     The M101 galaxy group in the extended sense includes the M101 subgroup (with NGC 5457 Pinwheel) plus the M51 subgroup (with NGC 5194 Whirlpool and NGC 5055 Sunflower), both subgroups at a distance of around 25 Mly.

  • Besides the Messier Pinwheel Galaxy (N5457), the M101 subgroup contains the two NGC dwarfs: N5474 (peculiar Sc) and N5477 plus 6 smaller galaxies.
     
  • The M51 subgroup contains 4 galaxies around the Messier Whirlpool (pair M51a-b, aka N5194-5195) including NGC 5229 (edge-on spiral), while another 6 galaxies are grouped around the Messier Sunflower (N5055), including NGC 5023 (edge-on spiral).

    

          We’re in the start of April, closing in on midnight (2019-04-04, 23:00 CEST DST, UT+2). The temp. is very mild at 8⁰C, with a relatively low 73% humidity and the dew point down at 4⁰C. The transparency is an OK 4-5/7 with a slight high haze still hanging around from the warm spring day, and the seeing is calm and steady at 8/10. There’s a new moon out of the way -30⁰ Alt. below the NW horizon, so the LP is a good suburban NELM 5.5 (SQM 19.0 @ zenith).

    
     I start my galaxy sweep of the M101 galaxy group from the North with the M101 Subgroup; In my 4” refractor at 16x in 2½⁰ FOV, the mixed SAB face-on spiral NGC 5457 (M101 itself, the “Pinwheel” galaxy) shows up using glass only as an E-W elongated hazy splotch with a small brighter nucleus. Using image intensification, I can glimpse the 3 main spiral arms: two branching out and down from the NW side, and one coming out and up from the SE side. Also, in the same field SE of the “mothership”, I can spot the companion NGC galaxy 5474 as a N-S elongated faint hazy spot, with a somewhat brighter core at the N tip.

    

M101-41mm.jpg
*click*

    

    
     For higher magnification, I now switch from the TV 41mm PAN to a TV 21mm ETH eyepiece, yielding 30x @ 2⁰ FOV (still with IIT). The Pinwheel galaxy structure is now more easily seen, with the large disc (1.7x the size of our Milky Way) and the three far-flung main arms that are sprinkled with large knots of star-forming H-II regions, several of which have received their own NGC numbers (I’ve tentatively labelled three on my snapshot). The asymmetric spiral arms with intense star formation in M101 is caused by tidal gravitational interaction with its four prominent NGC companion galaxies:  N5474 (the one closest to M101) plus N5477, N5204 and N5585. As mentioned, the dwarf Sc spiral NGC 5474 is easily observed S of M101, and I can even glimpse its distorted shape with the brighter nucleus displaced N (towards M101) and the fainter haze of the arms offset to the SW. Interesting!

    

M101-21mm.jpg
*click*

    

To-be-continued...

     -- Allan

    


Edited by AllanDystrup, 07 April 2019 - 07:20 AM.

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#349 AllanDystrup

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Posted 08 April 2019 - 02:26 AM

.    

The M101 Galaxy Group
M51 Subgroup

    

    

   M51 (the Whirlpool) is the brightest galaxy in the M51 Subgroup, that also includes M63 (the Sunflower); This subgroup in turn belongs to the elongated galaxy association that includes the M101 (the Pinwheel) Subgroup towards the NE .

    
     The large face-on SA spiral M51a (N5194) plus its peculiar SB dwarf companion M51b (N5195) form a conspicuous colliding galaxy pair connected by a dust rich tidal bridge. The galaxy interaction has enhanced the spiral structure of M51a while significantly distorting the shape of M51b. The bright bulges of the two M51 galaxies are evident, and both harbor an active supermassive black hole with accretion discs (AGN) that contribute to the brightness in visual as well as in X-ray emission.

        

      
     In my 4” refractor at 16x (TV 41 PAN, with IIT), I can glimpse the two main spiral arms of M51a curving around the core, and I can also easily see the amorphous hazy spot of M51b, but I can’t identify the tidal bridge between them. I can however glimpse the faint dot of the edge-on SB galaxy N5229, which is a more distant member of the M51 Subgroup to the NE of the Whirlpool, and I can also identify the E1 elliptical N5198 due S of the Whirlpool. The latter has a tidal tail towards the W from disruption of a smaller satellite, but this is way too faint to see with my equipment.

         

     M51-TV41.jpg
*click*
    

         
     Bumping up the magnification to 30x (TV 21 ETH+IIT), I can now study the galaxy arms of M51a and the disc of M51b in quite more detail, and with averted imagination I can at times think I detect the faint bridge between the pair of galaxies. I won’t call this a positive observation though...

    

 M51-TV21.jpg   
*click*
    

To-be-continued...

     -- Allan


Edited by AllanDystrup, 08 April 2019 - 09:07 AM.

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#350 AllanDystrup

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Posted 11 April 2019 - 01:35 AM

.

The M101 Galaxy Association
(M51 Subgroup)
M63 Galaxy Group (the Sunflower)

         

    

     As mentioned in the previous post, the M51 Subgroup has two gravitational centers: one around M51 (the Whirlpool) plus one around M63 (the Sunflower); And together the M51 Subgroup in CVn + the M101 Pinwheel Subgroup in UMa form the extended M101 Galaxy association. 

    

     After having observed the M51 galaxy pair with their smaller companions, I now pan my 4” refractor a bit further SW to the M63 galaxy with its satellites. M63 (NGC 5055, the Sunflower) is a SA flocculent spiral galaxy with an active galactic nucleus (AGN). In  a wide-field view using my 4" refractor at 16x (TV 41 PAN+IIT) the nucleus is seen as a bright, slightly E-W elongated core, embedded in a pale outer elliptic halo.

    

M63-41PAN.jpg
*click*

    

     Switching to a higher magnification of 30x (TV 21mm ETH+IIT), I can now see a hint of a ring around the central core plus some mottling in the faint outer disc, -- but these details are fleeting and hard to pinpoint.

    

M63-21ETH.jpg
*click*

     
     M63 is surrounded by 6 smaller companion galaxies, including the edge-on spiral NGC 2023 ~2⁰ NNW of M63 (this satellite is however outside the 2½⁰ FOV of my snapshot above taken at 16x magnification).

 

     -- Allan


Edited by AllanDystrup, 11 April 2019 - 01:43 AM.

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