Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - sgottlieb

Pages: [1] 2 3 ... 7
1
Observing Intents / Re: Observing Tuesday NIght?
« on: Yesterday at 06:31:20 PM »
I'm planning to also observe on Tuesday night -- either at Lake Sonoma (if the north bay forecast improves a bit) or else I'll head south to Fremont Peak or Deep Sky Ranch.

2
TAC Visual / Colliding Galaxies
« on: March 17, 2017, 02:39:48 PM »
I wanted to mention I have a featured observing article titled "Galaxies in Collision" in the May issue of Sky & Tel, which should be out shortly (the digital version is already available).  It includes a number of interacting Arp pairs including the Antennae (cover photo) and other interesting duos such as the Mice, the Tadpole, the Heron, the Grasshopper and more.  Some of these are fairly well known and others are pretty obscure.  If anyone would like more "info" on the article, let me know.



3
Joe, my anecdotal experiences may not be the best predictor, but here's been my experiences on two trips that time of year --

In mid-October '15, I observed at the Markdale site, along with John Hoey and Kemer Thomson.  I think the forecast was looking pretty bleak the day I flew to Sydney, so I was surprised the first half of the first night was clear (perhaps 4 hours).  The next day (Sunday) it rained all night, so not a great start at this point.  But then we had 5 consecutive all-nighters with very little or cloud-free conditions.  So, I ended the week exhausted from the number of hours of observing (6 out of 7 nights).  I check my notes again and SQM readings were consistently above 21.8 with several readings between 21.9-22.0.  I believe the star party last October/November had similar luck with the weather.  Locals Dennis Beckley and Bob Douglas attended, though you probably would have to contact them directly for their experiences.

In early November 2010 I observed at Coonabarabran, which is further from Sydney (perhaps a 6 hour drive).  The weather prospects looked dismal the few weeks leading up to the star party with consistently cloudy conditions and rain throughout New South Wales.  But although there were clouds during the daytime, it cleared by sunset on the first 4 days of the star party and I got in quite a bit of observing under impressive skies (SQM readings generally 21.85-21.89).   But we had clouds/rain for the last 3 nights, so we ended up with 4 out of 7 clear nights.

So, yeah, there is a risk with clouds/rains but I've rarely (if ever) returned from a trip to Australia bummed out by the weather (say with over half the observing time missed due to weather).  Conditions are drier further in the interior or perhaps on the west coast, but then you're really on your own in terms of planning a trip, and would have to lug along your own equipment.

Also, if you haven't been to southern hemisphere before and are only planning a single trip, then I would recommend going to the March/April star party as you get the full Milky Way overhead experience with lots of great nebulae/clusters that you haven't seen before.

4
I'll have to check it out.  I'm not sure how I got hooked on it, but I've actually watched a Australian melodrama (at least 3 seasons) that takes place in the 1950's called "A Place Called Home".  Full of stereotypes, prejudice and an over the top villain.  Nothing to do with astronomy, though.

By the way, the October event has been moved to a country sheep farm (Markdale) about 3 ½ hours west of Sydney.  Beautiful location that I observed at a year and half back.  SQM readings consistently above 21.8!  I know there's still openings if anyone has had a desire to observe in the southern hemisphere.


5
Observing Reports / Re: Some doubles around Gemini
« on: March 05, 2017, 06:38:15 PM »
Well done, Mark!  I'm guessing you were just running up against the mag limit of your scope/sky.  Also for some reason I often find the fainter companion of a close unequal, double appears dimmer than its magnitude suggests.

My notes on a several of these pairs are appended at the end, but here are a few more 2" or closer pairs in Gemini you might want to look at another time --

∑899 = ADS 4991
06 22 49.6 +17 34 27
V = 7.4/8.0;  Size 2.2"
18" (1/28/12): tight 2" white pair just cleanly split at 175x in fair seeing.  Crisper view using the 6" mask.

∑932 = ADS 5197
06 34 21.6 +14 45 08
V = 8.1/8.2;  Size 1.7"
18" (1/19/08): well-matched tight pair that at 1.65" that is just resolved at 175x.  Easy at 225x in good seeing.
18" (1/3/04): excellent evenly matched pair of mag 8 stars at 1.7" separation.  Splits at 160x and cleanly resolved at 215x.  Tangent airy discs with 6" mask at this power but easily resolved.

∑1037 = O∑166? = ADS 5871
07 12 49.1 +27 13 30
V = 7.2/7.2;  Size 1.1"

18" (3/10/04): clean split with 6" mask even at 220x!  This is a perfectly matched white pair.  This binary has a period of 119 years and is just past maximum separation (1.1").
18" (1/3/04): very close 1.1" pair of equal mag 7 stars.  Clearly double at 160x but not cleanly split.  Nicely resolved at 300x and with a 6" mask two nearly tangent airy discs are just cleanly resolved at 300x!
18" (3/24/03): very close, evenly matched pair (white/white) at 1.1".  Clean split in good moments at 300x.

∑1070 = ADS 5999
07 21 21.9 +34 01 36
V = 8.6/9.3;  Size 1.7"
18" (1/19/08): tight 1.7" pair but just cleanly resolved using 175x.  At 450x, tiny airy discs were resolved when the seeing was steady.

∑1081 = ADS 6038
07 24 08.9 +21 27 28
V = 7.7/8.5;  Size 1.8"
18" (1/19/08): fairly close 1.8" white pair is resolved at 175x.  Upping the power to 450x gave a wide split with clean star images.
---------------------------------------

Eta Gem = Bu 1008 = ADS 4841
06 14 52.7 +22 30 24
V = 3.3-3.9/6.5;  Size 1.6"
18" (4/10/03): Eta Gem is a challenging mag 3.3-3.9 (variable)/6.5 pair at 1.6" (slowly increasing).  Very large mag contrast with a yellow/orange primary.  Excellent at 300x and easy at 435x in good moments.  Supernova remnant IC 443 is close following.

∑942 = ADS 5258
06 37 40.6 +23 38 53
V = 10.1/10.1;  Size 3.5"
18" (1/28/12): perfectly matched 10th magnitude pair at 175x.  Fairly close (3.5") and nicely split at 175x.  Located 4' NW of mag 6.7 HD 47086.

∑981 = ADS 5570
06 55 28.4 +30 09 45
V = 8.8/9.0;  Size 1.1"
18" (1/19/08): this 1.1" pair was barely resolved at 175x and cleanly split at 225x.  At 450x, tiny airy discs were resolved and well separated.  This binary has a period of 5343 years and is still closing.

18" (3/7/04): very close 1.2" pair but cleanly resolved evenly matched duo.  Used both the 6" mask and at full aperture with a 9mm Ortho (250x).  Current separation at 1.2" is close to minimum.  Closing since discovery in 1831 (3.7").

Ho 342 = ADS 5725
07 02 50.5 +13 05 22
V = 8.0/8.7;  Size 1.2"
18" (1/19/08): very close 1.2" pair cleanly resolved at 300x.  Superb in good seeing at 750x with small airy discs.

∑1014 = ADS 5770
07 05 44.9 +26 08 25
V = 9.9/9.9;  Size 2.0"
18" (1/28/12): excellent perfectly matched 2" pair at 175x.  Cleanly split at this power but very close.

Weisse 14 = ADS 5875
07 12 48.2 +15 10 42
V = 7.8/8.9;  Size 2.1"
18" (1/19/08): this excellent 2" pair was just resolved at 175x and was beautiful at 300x.  Subtle colors.

∑1116 = ADS 6180
07 34 32.0 +12 18 17
V = 7.8/8.6;  Size 1.7"
18" (3/10/04): striking pair at 220x with the 6" mask.  Easily resolved at full aperture at 1.7".

∑1147 = ADS 6394
07 50 19.7 +24 31 56
V = 9.7/9.7;  Size 2.2"
18" (1/28/12): perfectly matched 2" pair just cleanly split at 175x.  Very similar appearance to ∑1014 = 9.9/9.9 at 2.0" observed a little earlier in the evening.

6
Registration is open for the 2017 OzSky "Southern Spring" star party in Coonabarabran ("astronomy capital" of Australia), which runs from October 15-22 (7 nights).  If you have any interest in observing in the southern hemisphere check out http://www.ozsky.org/spring.asp.  That's me on the ladder of a 30" in SQM 21.8-21.9 skies.

I'm planning to attend again (this is my 8th trip to Australia!), as this is a remarkable opportunity to see the Magellanic Clouds and more.  All equipment is provided (mostly 18" to 30" scopes) -- you basically just have to show up and enjoy the dark skies.  A number of bay area amateurs have participating in OzSky star parties including Bob Douglas, Peter Natscher, David Cooper, Dennis Beckley, James Webster.  If anyone has any questions or possible interest, let me know.

7
TAC Visual / Re: Double Star Epsilon Canis Majoris
« on: March 03, 2017, 09:18:07 PM »
Mark, here are two observations I've made.  I've split it in both 6" and 8" apertures -- even at a low elevation if the seeing was good.  I don't have a good quality small refractor, but I'm sure it can be resolved.  So, Wikipedia is certainly wrong.

6" (2/19/07): mag 1.5 Adhara is a challenging double with a 7.5-mag companion at 7.5" separation.  It was cleanly resolved in moments of steadier seeing (viewed at 15° elevation) at 175x using a 6" mask.

C8 (seen several times in the early 1980's) : difficult pair due to very large mag difference.  Visible with at least 100x and fairly easy at 165x in excellent seeing.

8
Observing Reports / Re: Dinosaur Point what a night, 23 February
« on: March 01, 2017, 02:20:51 PM »
I'll throw in my notes of NGC 2467 from Costa Rica on 30 Jan '06 using Ray Cash's 13.1" travelscope.  It looks like Jamie also observed it the same month from Dino, though methinks he may have the wrong day of that month.

Bright, large nebulosity at 75x using an OIII filter, ~4-5' diameter, surrounding a mag 7.5 star.  The main section is roughly mushroom shaped, extending generally south of the bright star.  The southern border is locally brighter along a strip oriented NW to SE.  There is a sharp light cut-off (apparently due to dust) passing to the north of the central star and oriented E-W.  Faint haze extends ~15' to the east.  To the north, fainter nebulosity extends 12' E-W, and brightens towards the east end at an elongated group of brighter stars (Haffner 18), oriented NW-SE.  Removing the filter this is a gorgeous low power Milky Way field with numerous faint stars peppered in the region of the nebula.

9
Observing Reports / Re: Frosti
« on: February 05, 2017, 11:16:25 AM »
Wow, a real Arp-fest!  Even NGC 2911, near the end of your report, is Arp 232.  Great report.

As Mark knows, I have an article coming up in a few months in Sky & Tel on Arp interacting galaxies and UGC 4881 = Arp 55 = The Grasshopper (last in the report) is one of the featured galaxies.


10
TAC Visual / Re: Venus/Neptune conjunction, Mars and 96 Aquarii
« on: January 29, 2017, 05:19:57 PM »

Later in the night I split doubles in Orion.  A highlight was STF 757: This was marked as a double star in my Cambridge Double Star Atlas but without designation.  It showed as a lovely double-double at 553x: All the stars were near equal magnitude at 8-9.  The pair to the east was well separated but another, to the west, was very tight, about 1 disk separation.  I stayed on this for a while since it was such a beautiful surprise.  After coming in and checking a double star catalog, I found it to be STF 757.  The AB pair is A mag 7.96, B 8.33 with 1.5”.  The other double is in fact two more pairs with A, AC (8.69 mag, 51.3”, PA 87°) and AD (8.52 mag, 41.9”, PA 79°).  There is an AE pair which I didn’t notice, and CD are listed as a pair.  Quite a sight.

I had a look at the STF 757/758 "double-double" last night while observing at Lake Sonoma.  This is a beautiful quadruple!  The seeing was good, so even at 200x I could cleanly split the 1.5" pair using an 8-inch mask on my 24" and of course the 11" pair just east was easy at any power.  Excellent recommendation, Mark!

11
TAC Visual / Re: Venus/Neptune conjunction, Mars and 96 Aquarii
« on: January 17, 2017, 05:23:22 PM »
STF 757 and 758 sounds like a very nice double-double!

I don't know which of these are plotted on the Cambridge Double Star Atlas, but here's a list of some more close doubles in Orion that I've observed in my 18" (often with an off-axis 6" mask) --

14 Ori = ADS 3711 (5.8/6.7 at 0.8").  Split at 450x (in my 18") at Willow Springs
32 Ori = ADS 4115 (4.5/5.7 at 1.2").  Clean split with 6" mask at 490x.
33 Ori = ADS 4123 (5.7/6.7 at 1.9").  Split at 175x with 6" mask
52 Ori = ADS 4390 (6.0/6.1 at 1.0").  Clean split at 300x with 6" mask.
STF 849 = ADS 4730 (9.1/9.5) at 0.9").  Clean split at 490x.
STT 517 = ADS 3799 (6.7/7.0 at 0.65").  Clean split at 450x.
Ho 22 = ADS 4823 (8.5/8.6 at 0.9").  Clean split at 450x.

12
Observing Intents / Re: OI - Fremont Peak Tuesday 1/17/2017
« on: January 15, 2017, 08:24:26 PM »
This week is looking bad as far as observing (unless you want to get out just a few hours on Monday night) and even long range forecasts don't look good until the end of the next week.

But Peter has the right idea -- it will probably have to be a last minute decision on the weather as well as the flexibility to get out on a weekday if that's the best opportunity.   It's difficult or hopeless to plan on a Saturday night this time of year.

--Steve

13
Equipment Discussions / Re: Fits In A Fit
« on: January 06, 2017, 06:34:04 PM »
Mark's adventures with his Honda Fit makes me nostalgic for my circa 1980 Civic CVCC. I used to drive it to Fremont Peak with my solid tube and beefy 13.1" Odyssey I as well as a C-8, tripod and of course all observing and camping paraphernalia.

14
Observing Reports / Blazers, Seyferts, Double Rings from Lake Sonoma
« on: January 06, 2017, 12:42:18 PM »

On two consecutive Wednesdays (21st and 28th of December) I observed under clear skies at Lake Sonoma, located 30 miles north of Santa Rosa just above numerous Sonoma county vineyards -- this is the Lake just before crossing the bridge along Rockpile Road.

On both evenings we had small groups at the Lone Rock lot, in the hills above the lake (the photo was taken as I arrived on the 21st). The first Wednesday I was joined by Bob Douglas with his 28-inch f/3.7 Starstructure and Carter Scholz with a homemade 16-inch with Zambuto optics. Conditions were excellent - perfectly clear, fairly good transparency for this site (SQM readings hit 21.4 by 11:00 PM), perfectly calm with no dew. I returned on the 28th with Bob and we were joined by Mark Toney (20” Teeter Dob) along with a friend. Again we had perfectly clear skies with SQM readings in the 21.3-21.4 range and good seeing. Both nights we started observing around 6:30 and closed shop by 12:30 and over those 12 hours were very productive – I logged a total of 90 different objects in my 24-inch f/3.7 Starstructure. My observing list in included a mix of interacting and other unusual galaxies as well as a few galaxy groups and I’ve highlighted several of these below.

I started off both evenings by taking a look at the amazing blazar CTA 102, which at a redshift z = 1.037 has a light travel time of 8 billion years! Normally this quasar shines dimly at 17-17.5 magnitude, but is known to be an OVV — an Optically Violent Variable quasar. In the past couple of months it experienced a historic outburst reading reaching mag 12.7-12.8 when I took a look in November. It’s been fluctuating wildly in the past few weeks — on the 21st I logged it at mag 12.7 and was impressed that it was easily seen when I added an 8-inch aperture stop to my scope. But on the 28th it appeared at least a half-magnitude brighter than a nearby mag 11.7 star, so was certainly mag 11.1-11.3 and has now been glimpsed in down to a 50mm refractor. Wow!! When I later checked on the AAVSO web site, I found that several observers measured magnitudes in the 11.2 range, so my estimate was accurate. This latest incredible outburst is over 300 times brighter than its “rest” magnitude. I just noticed the Fermi Gamma-ray Space Telescope also recorded an outburst of 135 times its average gamma-ray flux on the 28th, making CTA 102 the brightest gamma-ray source in the sky.



NGC 309 + IC 1602
00 56 42.8 -09 54 50
V = 11.9; Size 3.0'x2.5'; Surf Br = 14.0; PA = 175°

This beautiful grand-design galaxy is one of the largest (diameter ~225,000 light years) and most luminous known spirals (absolute blue magnitude = -22.52). Even at a distance of 260-270 million light years it has a V mag of 11.9! In fact Arp used this galaxy as an example of a discordant redshift — he felt it was just too large for its redshift and mentioned that M81 could comfortably fit in between its gargantuan spiral arms. It also appears to be something of supernova factory, hosting 4 in the past 17 years: SN 2014ef, 2012dt, 2008cx and 1999ge.

In my 24” it was fairly faint but moderately large, roundish, fairly low but uneven surface brightness, contains a brighter core that increases somewhat to the center. I noted hints of spiral arms in the halo (slightly brighter arcs) — this was before viewing an image. A mag 12.5 star is 2’ NNE and mag 15 star is off the west side, 1.5' from center.

Nearby is IC 1602, which lies 13’ WSW. This galaxy is the brightest member of Abell Galaxy Cluster (AGC) 117 with a redshift-based (z = .055) distance of ~738 million light years. I noted IC 1602 as fairly faint, round, 20" diameter, slightly brighter nucleus. AGC 117 is one of the galaxy clusters in the Pisces-Cetus Supercluster, one of the largest known structures in the universe (see http://www.atlasoftheuniverse.com/superc/psccet.html)





Arp 54 = VV 453
02 24 00.9 -04 41 42
V = 14.2 / 15.9; Size = 1.0’x0.55’ / 0.4’x0.3’

Arp 54 is a little-known interacting pair at a distance of ~570 million light-years. It shows up in infrared surveys, as a radio source as well as an x-ray source, so it apparently is experiencing very vigorous star formation or perhaps has an obscured active galactic nucleus (AGN) — both signs of an interaction. Arp placed it in his classification of "Spiral galaxies with high surface brightness companion on arm”, though it doesn’t appear that the arm from the larger galaxy reaches the smaller galaxy. The edge-on to the south is not related to Arp 54.

Using 375x the larger galaxy (PGC 9113) appeared fairly faint, elongated 3:2 E-W, 30"x20", fairly low surface brightness, weak concentration. Its interacting companion PGC 9107 is just 0.9' WSW. It was a very small faint glow, only 12" diameter. Although it easily popped into view with averted I couldn't hold continuously. A mag 14.4 star is 0.5’ SW.





NGC 7805/7806 = Arp 112 = VV 226
00 01 28.4 +31 26 16
V = 13.3 / 13.5; Size 1.2’x0.9’ / 1.1’x0.8'; Surf Br = 13.2 / 13.2; PA = 47° / 20°

Arp 112 is an interacting triple system consisting of NGC 7805/7806, along with KUG 2359+311, a strange arc-like galaxy. NGC 7806, the galaxy in the middle of the image, is also a gravitationally disturbed system with a thin tidal tail to the north. It’s not known whether KUG 2359+311 (Kiso Ultraviolet Galaxy) is a pre-existing third galaxy or the remains of one of the other galaxies — it looks like a detached spiral arm to me.

Through my 24”, NGC 7805 appeared moderately bright (V = 13.3), fairly small, compact, very slightly elongated SW-NE, 25"x20", small bright core and even brighter stellar nucleus. Forms a similar pair with NGC 7806 just 50" NE. A mag 13.5 star is 1' west. Other than a different orientation, NGC 7806 (V = 13.3) is a visual twin of 7805. KUG 2359+311 was only marginally glimpsed in the 24-inch (V = 16.3), so I asked Bob Douglas if we could look at Arp 112 in his 28-inch. By bumping the power to 427x we were able to glimpse a small narrow glow in his scope.





Markarian 1018 = UGC 1597
02 06 16.0 -00 17 29
V = 13.9; Size = 1.0’x0.5’; PA = 0°

Visually, there’s nothing remarkable about this galaxy, which appears to be a coelesced merger of two galaxies. Using 432x I logged it as "fairly faint, slightly elongated N-S, 25"x20". Two 13th magnitude stars are 50" NW and 1.0' W and a mag 14.5 star is 1.0' ESE."

But astrophysically Mrk 1018 is quite unusual. It’s a Seyfert galaxy, a type of spiral with an active galactic nucleus powered by a massive black hole and whose spectrum contains emission lines from highly ionized gas. Type 1 Seyferts contain extremely broad optical emission lines indicating the nucleus contains hot gas near the accretion disc that’s moving/expanding at very high speeds. Type 2 Seyferts display only narrow emission lines, while Seyfert 1.5, 1.8 and 1.9 are intermediate cases. The two main classes are thought to reflect different activity levels of black hole feeding, though possibly the viewing angle of the accretion disc is a factor.

Historically, Mrk 1018 has been classified as a type 1.9 Seyfert. But in the 1980s, prominent broad lines appeared in the optical spectrum and it changed its classification to a Type 1 AGN. In 2006, though, it was announced that in the past five years Mrk 1018 has returned to its original state type 1.9 state (see https://arxiv.org/pdf/1609.04423v1.pdf). This second transition is thought to be due to a decrease in the black-hole accretion rate.





Arp 200 = NGC 1134 + UGC 2362
02 53 41.2 +13 00 53
V = 12.1; Size 2.5'x0.9'; Surf Br = 12.8; PA = 148°

Halton Arp placed NGC 1134 in his category of “Galaxies with material ejected from nuclei”. Probably he is referring to the “tidal plume” off the upper right end of the galaxy generally extending in the direction of UGC 2362, the chaotic blue galaxy to the west. These two galaxies have identical redshifts so likely experienced a “close encounter” in the past with the arm of NGC 1134 pulled out by gravitational tides.

At 375x NGC 1134 appeared fairly bright, elongated 2:1 or 5:2 NW-SE, ~1.2'x0.6', sharply concentrated with a bright core and fairly bright, sharp stellar nucleus. It was slightly brighter along the east edge with averted vision — probably the bright section of the eastern spiral arm on Rick Johnson’s image. A mag 13.6 star is 50" NE of center. UGC 2362, 7’ to the west, appeared faint, very low surface brightness patch ~20" diameter (probably the brighter central part of this Magellanic system). A mag 14.8 star is 0.8' S.





IC 1767
01 59 59.4 -11 04 44
Size 1.7'x0.6'; PA = 75°

At 375x I called this galaxy "fairly faint, moderately large, elongated 5:2 WSW-ENE, ~1.2'x.0.5', large brighter core, no sharp nucleus. The halo brightens slightly at the WSW edge - perhaps a knot in the galaxy?"

I was pleased when I checked later and found the PanSTARRS-1 image above clearly shows a small galaxy (identified as 2MASX J01595678-1104533 in NED), at the position I noted. Although this galaxy appears to be superimposed, I don’t know whether the companion is actually at the same distance (no published redshift) or possibly in front of IC 1767.





NGC 1713 group = LGG 120 = WBL 110
04 58 54.5 -00 29 20
V = 12.7; Size 1.4'x1.2'; Surf Br = 13.3; PA = 45°

NGC 1713 is the brightest in a loose galaxy group called LGG 120 or WBL 110 at roughly 200 million light years. The group includes NGC 1709 and several fainter UGC and CGCG galaxies. NGC 1713 appeared fairly bright, oval 4:3 SW-NE, 0.8'x0.6', gradually increases to the center. NGC 1709, just 2.7’ WNW, appeared fairly faint, elongated 4:3 SW-NE, ~0.4'x0.3', very small or stellar nucleus. A mag 12.3 star is 50" NW. The following members of the group were tracked down (offsets given with respect to NGC 1713). Only the two closest are shown on the SDSS image above.

CGCG 394-055, 7.7’ SW: Fairly faint, fairly small, slightly elongated ~N-S, ~20"x15", slightly brighter core. Forms a close pair with CGCG 394-056 1.3' NNE.

CGCG 394-056, 6.6’ S: Faint, very small, round, 12" diameter. A mag 13.5 star is attached at the southeast end. Mag 8.9 HD 31724 is 5' W.

UGC 3221, 24’ S: Fairly faint, thin edge-on 6:1 NNW-SSE, ~30"x5", even surface brightness. A mag 14.5 star is superimposed at the south end. A mag 9.2 star is 4.7' S as well as a nearby mag 9.9 star.

UGC 3214, 26’ NW: Moderately bright, fairly large edge-on 4:1 SW-NE, at least 1.6'x0.4'. Contains a bright, elongated bulging core and much fainter extensions.

CGCG 394-053, 21’ NNW: Fairly faint, fairly small, elongated 2:1 NW-SE, 30"x15”.





NGC 741 group
01 56 21.0 +05 37 44
V = 11.1; Size 3.0'x2.9'; Surf Br = 13.5

This group (called WBL 061) resides in Pisces at a distance of ~250 million light years and is dominated by the NGC 741/742 double system. NGC 741 has an unusually large halo, sometimes indicative of galactic cannibilism and if you look carefully there’s a small stellar like object immediately to the left of the nucleus of NGC 741. Perhaps a former companion that strayed too close and is now falling into the nucleus of NGC 741? NGC 741 has a extended X-ray halo reaching a distance of 19’ from its center. Furthermore, twin radio jets emerge from the nucleus of NGC 742 and spread into a larger lobe that encircles NGC 741.

Visually, NGC 741 appeared bright, moderately large, round, sharply concentrated with a small very bright core that increases to the center. The halo increases with averted to over 1’ diameter. A mag 11 star is 2.4' NW. NGC 742 is just 0.8' E of center at the edge of the halo at a projected separation of ~55,000 light years. This is a small galaxy but has a high surface brightness. It was moderately bright, round, 15” diameter. The following half-dozen galaxies are within 15’ of NGC 741 and share the same redshift.

CGCG 413-006 (often misidentified as IC 1751), 1.5’ NW: Fairly faint, very small, slightly elongated N-S, 0.3'x0.2', sharp stellar nucleus. The mag 11 star lies 1.4' W.

CGCG 413-002, 3.3’ SW: Fairly faint, very small, round, 12" diameter.

CGCG 413-001, 9.5’ NW: Very faint, very small, elongated ~2:1 ~E-W, 18"x9”. Once picked up could just hold continuously with careful averted vision.

CGCG 413-010, 11’ NNE: Faint, very small, irregularly round, ~15"x12".

UGC 1425, 12’ NE: Moderately bright, small, roundish, 18" diameter, high surface brightness, occasional sharp stellar nucleus. Increases a bit in size with averted.

UGC 1435, 15’ E: Faint, oval 3:2 SW-NE, 30"x20", very low surface brightness patch, no core or zones. Collinear with two 14th magnitude stars 2' and 3' E.





ESO 474-026 = Arp-Madore 0044-243
00 47 07.5 -24 22 14
V = 13.7; Size 1.2'x0.8'; PA = 175°

ESO 474-026 is a unique double-ringed galaxy with two perpendicular rings -- both an equatorial ring and a polar ring surrounding a central nearly spherical galaxy (the only component that was visible). It is thought to be have resulted from the major merger of two similar mass haloes. There is no nearby “hit and run” collider galaxy in the vicinity. ESO 474-026 is on a list of the most luminous galaxies (Cappi et al. 1998) and a strong source of far-infrared and CO emission. Its nuclear spectrum indicates active star formation.

Visually it appeared fairly faint, irregularly round, 25" diameter, very small bright nucleus with a stellar peak. The Redshift-based (z = .0527) distance is roughly 700 million years so I wasn’t expecting to see anything of the ring structures. But it was fun to contemplate this blazing beacon that shines at a relatively bright mag 13.7 over this vast distance.


15
Observing Reports / Re: galaxies galore
« on: January 06, 2017, 12:17:24 PM »
Here's a recommendation to put NGC 2820 on your "To Do" list, Jamie.  The challenge is really the attached companion that Mark mentioned -- NGC 2820A.  I saw it ages ago in my 17.5", but never tried in a smaller scope.  It's really an attractive pair in my 24".

24" (2/22/14): fairly bright, very large, very thin edge-on 7:1 WSW-ENE, ~2.8'x0.4', very weak concentration, mottled appearance though the surface brightness is not high.  NGC 2820A dangles just south of the west-southwest edge.  It appeared faint, small, oval 3:2 SSW-NNE, 18"x12", occasional stellar nucleus.  NGC 2814, a smaller edge-on, lies 3.7' W.

Pages: [1] 2 3 ... 7