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A probable GC has been announced quite recently from the Pan-STARRS survey. The object is designated Laevens 3, and the discovery paper (available on the arXiv at http://arxiv.org/pdf/1507.07564) came out end of Oct 2015. Here are the J2000.0 coordinates from SIMBAD:
Laevens 3
RA: 21 06 54.3
Dec: +14 58 48
The high-res image from the paper is below:
Attachment 2090
The POSS II Blue image is below:
Attachment 2091
Clear Skies
Regards
Akarsh
Early this AM right before 18 degree Akarsh and I gave this new found object a go. I was surprised how bright the glow was when I swept it up at 375X it was a direct vision glow
much easier than I thought it would be. The best view this night was at 610X. I did not resolve any stars this AM and only saw it as a small round direct vision glow. I did a eyepiece drawing and will post it below.
I think this globular suspect will be within reach of many scopes on this forum. I was really surprised how easy this object was.
Laevens 3
Attachment 2092
Dear DSF
Attached is my observation log. I concur with Jimi on almost all aspects, except I didn't see the glow as big as Jimi did. I should also mention that at lower power, I felt it looked a little elongated (as drawn) and at higher power, it felt more roundish -- Jimi saw it round both times.
I too think that it is accessible in smaller aperture given that it could be held steadily and was almost direct vision.
Attachment 2093
Clear Skies
Regards
Akarsh
Congratulations, Jimi and Akarsh, on snagging Laevens 3! I'd be surprised if this wasn't the first visual observation. I'm jealous as Howard Banich and I missed viewing it by one night (we were both observing at Jimi's during Texas Star Party week).
A minor correction -- the original pre-print announcement was posted on arxiv.org in late July 2015 and revised in late October.
For some reason, SIMBAD classifies this object as a GALAXY, although the Laevens et al paper concludes "The characterization of Lae 3 suggests that it is a GC, with properties similar to ‘young outer halo’ GCs."
Looking at the poss II Image of Laevens 3 Akarsh and I saw a rather large really faint glow near by. We enhanced the image below and you can see that it is some kind of faint nebula.
Attachment 2095
The first night we observed Laevens 3 the anonymous object was super faint and I was not sure it was there. Last night the 11th under excellent transparency and at 697X the object was barely visible with AV. I did a quick field drawing to confer my observation and my drawing was spot on. Akarsh also cold see the feeble glow and conferred with my observation.
I am not sure what this object is but I plan to contact DR. Laevens to see if they got a ID of it from the Pan Stars survey. Hopefully there will be more on this later.
OK - i give it a go with my 12" :DQuote:
Originally Posted by Jimi Lowrey
CS
Norman
Dear Steve,
I'm sorry we had so many poor nights. But last night was very good, indeed (second observation of Laevens 3). We had airglow problems the previous night (first observation of Laevens 3). I think astronomy-wise it might be better next year as we have ENSO-neutral / La Niña.
Regards
Akarsh
Dear Jimi,
Regarding the anonymous object, in my observation, I'd say "see" is an overstatement. But I certainly did feel the existence of a glow there. I got the N-S position down pretty accurately, but marked the glow's center slightly east of where it appears in the POSSII plate.
Regards
Akarsh
In my limited understanding, it seems like they came to this conclusion from the size-luminosity plane in Fig. 4 of the paper, where it seems like most dwarf galaxies lie in the band with absolute surface brightness less than 26 mag/sq arc sec. whereas most globulars have higher absolute S.B.. To quote the paper (Laevens et. al. arXiv:1507.07564v2 [astro-ph]):Quote:
Originally Posted by Steve Gottlieb
"The top panel shows the size-luminosity plane while the bottom panel focuses on the distance-luminosity plane. These parameters can already be a first indicator as to the nature of these objects..."
Their discussion of Laevens 3 has some interesting information too:
"The small half-light radius of Lae 3 (7 ± 2 pc) places it well within the regime of GCs. With a relatively young age (∼ 9 Gyr) and stellar populations that are not very metal-poor ([Fe/H] ∼ −1.9), it would be natural to classify Lae 3 as a “young outer halo” GC found in the outer region of the MW halo (Mackey & van den Bergh 2005). However, some caveats should be noted..."
Clear Skies
Regards
Akarsh
Congratulations Jimi and Akarsh on your visual observation. I guess this could very well be the first visual observation of this newly discovered object?!
I just quickly glanced through the paper. It says absolute visual magnitude -4.4 +/- 0.3 mag and distance modulus 19.14 +/- 0.1 mag. Thus, the visual magnitude must be 14.74 +/- 0.4 mag. That's not really faint. And the diameter is 0.8 arc minutes.
Those of you who succeeded in observing it, how would you compare this object with the faintest Palomar globular clusters?
Clear skies
Robin
Here's an observation of Laevens 3 from a week ago ---
Jimi Lowrey, Akarsh Simha and I took a look through my 24-inch f/3.7 at the Golden State Star Party (outside Adin, California)
It was seen at 322x as an extremely faint, very small, roundish glow, perhaps 12" diameter. I needed averted vision and it was seen only part of the time, but I noted the exact position with reference to some nearby field stars without knowing the location in advance. Specifically, a 14th mag star is 1' west; it's the third and faintest star in a string with a mag 13.6 star 1.6' north and a mag 12.4 star about 2' further north.
Has anyone else gone after this recent discovery?
On July 27, we had a more transparent than usual for July night, and I had a look at Laevens 3 in the 30". My notes:
"Tiny g.c. Seen at 296x as a diffuse glow, held with averted vision, detectable with direct vision. At 550x, held with averted vision presenting as a mottled glow, resolving sporadically for brief moments into a handful of stars (4-6) superimposed over the glow.
Nearby galaxy LEDA 1471211 held as a uniform glow, brighter in the center. LEDA 1471623 intermittent using averted vision at 550x."
Last night, July 29, I looked at it using the 82":
"G.C. detected even at low power as a fuzzy glow. With increased power and averted vision, a sprinkling of ~ two dozen stars consistently popped in and out, with a fairly large persistent glow in the background.
LEDA 1471211 and LEDA 1471623 both easily seen."
No popping of individual stars but a positive report with 27" under good transparency and seeing:
27", 293x, seeing II-III, NELM 7m+
not to difficult, round, a little bit concentrated glow which can be hold with averted vision repeatedly for several seconds, two other observers confirm detection
Hi folks,
Last night I observed some deep sky objects in the constellation of Delphinus, so I though I should give Laevens 3 a try. However, it was a negative sighting. But there's nothing to loose by trying to go for it, anyway. :-) I used my 12-inch Dobsonian, which probably isn't enough aperture. Naked eye limiting magnitude was 6.6. I could easily see the line of stars of 13th to 15th magnitude that can be seen on Akarsh's monochrome POSS Blue image at the lower left of the blue circle (this line of stars is actually a tangent to the blue circle). The faintest one of these is a 15.6 mag star which I could see with averted vision most of the time.
Has anyone observed this object with less than 24 inches of aperture?
Best regards,
Robin
Hi Robin,
nice that u tried - i will second that these nights with my 12" :-)
greets
Norman
Hello
I would expect that this object would need at least 16 to 18 inches of aperture and dark skies, but as we know well, any such assumption is against the spirit of this forum and of science in genberal. It's good to see the reports of attempts in 12"!
BTW, I recently noticed that SIMBAD has a system for pointing out errors in the database, so I have reported one saying that Laevens 3 must be Gl? (Possible globular cluster) and not G (galaxy).
http://cdsannotations.u-strasbg.fr/a...Object/9705361
Clear Skies
Regards
Akarsh
Hi Robin and all,
last night i had a try with my 12" too. My conditions might be very the same as Robin´s - around 6m5 NELM. But seeing was kind of poor. Star field was easy to locate - hopping from the globular cluster in Delphinus. My results are the very same as Robins too: i could see the faint star which Robin mentioned, especially at higher power. For me this star was a good mark too - it is a good indicator to compare conditions observing with 12" i´d say. Magnification was up to 270x in the rare moments of better seeing. Add to this there has been some wind - a bit too strong for objects at the visual limit. It disturbed a lot.
I won´t give up and give it another try under better conditions - better seeing, better transparency.
CS
Norman
Laevens to see if they got a ID of it from the Pan Stars survey. Hopefully there will be more on this later.
Hi everyone,
back in 2016 I tried to observe Laevens 3 with my 12" Dobsonian, after I had read about its 14.7 magnitude, but I didn't succeed. On Tuesday I gave it a try with 20" aperture and finally it was successful. I could glimpse a faint and diffuse patch at averted vision intermittently. It is located roughly in the center of a 3 arc minute triangle of 13 - 15 mag stars. Additionally I observed nearby galaxy PGC 1471211, which was fainter and more difficult than Laevens 3.
Anyway, now I understand why I was not able to observe it with 12". :-) It was not an easy object even with 20".
Clear skies,
Robin
Cool Robin, congrats!
I am still waiting for superb conditions to give it another try with my 12" :-))
CS
Norman
Hi everyone,
Started an attempt recently with my 14 inch and with a 21 inch newton. Although I tried several mangification 600x down to 180x (21 inch Newton) but could finally not see anything. Conditions were fair with SQM-L readouts around 21.4.
Oliver
Hi all,
Just right back from a recent Namibia trip. I gave Laevens 3 another try and I succeeded. At 178x & 278x I could spot a faint glow which I could successfully hold using averted vision. Relatively easy to see not extremely faint. Conditions where Bortle 1 sky, good transparency and fair seeing conditions.
Oliver
Was this with a 21" telescope?Quote:
Originally Posted by oliva
BTW, now that we have access to better imaging from the Legacy Survey, the mystery object near Laevens 3 that Jimi and I noticed and checked out in the eyepiece (marked "Anonymous" above) looks like a tidal extension from the interacting pair of galaxies nearby...
Attachment 4787
I forgot to mention the used telescope. It was a 25“ Dobsons.
Oliver
Another try of spotting Laevens 3 this time with a smaller scope, my 21” Dobson and the GC appeared at 231x relatively easily. Using averted vision the GC could be hold as a faint glow with increasing brightness towards the center. I was really surprised how easy it could be seen. SQM-L readouts around 21,5.
Oliver
Thanks, this is encouraging. Tells me I should perhaps try with my 18".Quote:
Originally Posted by oliva
Hi everyone again,
I tried to spot Laevens 3 with my smaller scope in my home region under Bortle 3 sky and interestingly I succeeded again. Scope was a 21 inch Newton. The GC could be hold using averted vision and was relatively easy to spot. Forgot to write down the used magnification, but I think it was 238x. SQM-L readouts were around 21.48 in the Delphinius constellation.
Oliver
From what I read here in your comments, you own (at least) three telescopes: a 14", a 21" (which you refer to as your "smaller scope") and a 25". Is that correct? Did you try to observe this GC with your 14" as well?Quote:
Originally Posted by oliva
Wouter
Hi Wouter,
The 25" was a rental at Tivoli Astrofarm. The 14" I owned myself in 2013, the 21" is a second hand home built Dobson which I use since last December. I tried Laevens 3 with the 14" in 2021 too but could not spot anything. But the star field is tricky and I used a screenshot from Aladin so I also didn’t succeeded with the 21 the first time recently because I accidentally observed a field nearby, which looks like that at the correct position. So, possibly I was with the 14" when I observed the GC in summer 2021 at the wrong position also even because I tried the same night with a friend’s 21", but could not see anything too. Ok, it’s a little bit complicated...
Oliver
This is actually a double post to those from 31. august. Didn’t notice that I already posted my observation.Quote:
Originally Posted by oliva
Oliver
Since I had access to a 36-inch telescope for one clear evening and was waiting for other objects to get higher, I took a look at Laevens 3. SQM-L reading was no better than 21.15 after darkness. Was surprised to be able to detect it at just 150x and it was easy at 334x! Now I will have to try for it in my 16-inch at 600x under my 21.4 skies at home. Pretty sure I've got a good shot at seeing it. Thanks to Akarsh for starting this thread since there isn't a similar thread on Laevens 3 on CN.
Scott
Okay, Akarsh was right. I could see it occasionally at 300x in my 16-inch as a tiny but nonstellar glow with averted vision. A tough but doable for GC that is 200,000 light-years distant and was discovered less than 8 years ago! I would predict that under optimal conditions, it could be glimpsed in a 14-inch.Quote:
Originally Posted by akarsh
Scott H.
Hi all,Quote:
Originally Posted by ScottH
I tried to spot Laevens with my 14 inch Newton (350 mm) in two different nights under Bortle 2 skies but I couldn’t detect the GC so far. I used 65x, 114x and 168x to reveal the glimpse of Laevens 3. But nevertheless it was not visible.
Oliver