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Messages - sgottlieb

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1
Observing Reports / Re: Lake Sonoma 10/21/17
« on: Yesterday at 07:08:53 PM »
Glad to hear you and Ray are out observing again!  I hope to join you in the next couple of months.

I just got back from the OzSky star party in Australia.  We had 5 clear nights out of 7, so needless to say I'm exhausted and it'll take awhile before entering all my notes.  But I'll post a report as soon as I can.

Steve

2
Observing Reports / Re: Globular Cluster hunting -- in Barnard's Galaxy!
« on: August 06, 2017, 03:36:48 PM »
NGC 1049 = Fornax 3 is the brightest globular, then Fornax 4 and 5 a bit smaller and fainter.  Fornax 2 is the faintest of the main 4, which are all visible in a 10-inch or 12-inch.

I would be surprised if you could pick up Fornax 6 as I called it "extremely faint" in the 48-inch, but Uwe Glahn writes that he glimpsed it a 18" from Namibia.  My full description was "extremely faint, small, very low surface brightness spot, ~0.3' diameter.  Located 7' due north of globular Fornax 4.  Pinpointing the location, a mag 15.8 star is 1.6' W and a mag 16.5 star is 2.1' WNW."   But Fornax 6 isn't a globular anyways -- it's either a group of extremely faint stars (~21st mag) or even distant galaxies!

There is a 5th globular, though -- Fornax 1, which is much fainter than the other 4 (perhaps close to 16th mag).  Perhaps this is the one you looked for?

3
Observing Reports / Re: Globular Cluster hunting -- in Barnard's Galaxy!
« on: August 05, 2017, 09:49:00 PM »
For next fall, I was just approved for an observing article in Sky & Tel on Local Group globular clusters, so I certainly hope to get a look at SC 6!

4
Thanks Mark and Marko for the comments and posting the finder chart.  SC 6 is already on my observing list as it's only a 1/2 magnitude fainter than SC 7, but I didn't take a look at Grandview.  Maybe next month.  For the record, here are the coordinates of these two exotic objects.

SC 6   19 45 37.0 -14 41 10.8
SC 7   19 46 00.7 -14 32 35.0

A 2005 study titled "The Globular Cluster System of NGC 6822" (https://arxiv.org/pdf/1506.00951.pdf) gives the following magnitudes (rounded to nearest tenth):

SC 6  15.4V
SC 7  14.8V

Let us know if anyone gives these a try.


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Observing Reports / Globular Cluster hunting -- in Barnard's Galaxy!
« on: July 28, 2017, 06:01:55 PM »
For the July new moon I observed for 4 nights in the White Mountains above Bishop (Grandview Campground at 8500 ft), just below the Ancient Bristlecone Pine Forest.  Our group included Paul and Debbie Alsing, Kemer Thomson, John Hoey (all from the San Diego area), Jimi and Connie Lowrey (from west Texas but drove from Florida) and bay area locals Carter Scholz and Rick Linden.  The weather turned out great and the Detwiler fire southwest of Yosemite didn't impact us, though I drove through the smoke in Yosemite to reach the site.  SQM readings were generally in the 21.6-21.8 range, though occasionally below 21.5.  The largest scope was Rick's 32", which nearly dwarfed my 24" Starstructure.

Instead of posting a long list of observations (I logged 125 objects), I'll mention just one -- a Sagittarius globular that actually resides in Barnard's Galaxy (NGC 6822).  Edwin Hubble was the first to investigate Barnard's Galaxy in detail in 1925 (http://cdsads.u-strasbg.fr/full/1925ApJ....62..409H).  His study included a table of 10 nebulous objects within Barnard's Galaxy.  Most of these turned out to be HII regions (including 2 great visual targets), but Hubble VII turned out to be the first confirmed ancient globular in this galaxy.  The location, though, creates a problem -- its a tiny 16th magnitude speck superimposed on the glow of the galaxy and a very nasty visual target.  I was successful observing it twice from GSSP back in 2010 with my 18", though it was quite challenging (barely non stellar and lost in a maze of other dim stars within the galaxy).  I figured that was the last GC I'd see in Barnard's Galaxy

Four new globular discoveries in this dwarf galaxy were announced in 2011 but these seemed too faint for visual targets.  Then in 2013 three more were identified (so the current total is 8 ) and globular #7 (coincidentally the same number as Hubble's object) seemed a reasonable target for my 24".  When I added it to my observing list, I had no idea what to expect as I've never read of amateur observations of these globulars. You can read the discovery paper at http://adsabs.harvard.edu/abs/2013MNRAS.429.1039H, where it's called SC 7 (Star Cluster 7)

SC 7 is in the outskirts of Barnard's Galaxy, 22' NE of the center of the galaxy and well outside the visual extent -- that makes identification much easier!  Once the general field was centered using the 6mm Delos (375x), both Jimi Lowrey and I were surprised to quickly notice a non-stellar glow without first examining an image of the galaxy.  SC 7 was faint in my 24-inch, but clearly non-stellar, roughly 6"-8" diameter and 15-16th magnitude.  The globular could be held steadily when we backed the magnification down to 282x and possibly had a brighter stellar nucleus.

If you're curious about the distance, Barnard's Galaxy is ~1.6 million light years away.  For comparison, the most distant Milky Way globulars are 300 to 400,000 l.y. away, so this one is at least 4 times that distance!  I believe an 18" scope should catch this object from a dark site, if you know the precise location.

-- Steve 



6
Observing Reports / Re: Speaking of subtle...
« on: July 27, 2017, 10:22:09 PM »
Great set of targets, Mark!!

As far as GN 18.32.5 = PNG 27.0 +1.5, it's definitely a planetary neb and not a reflection nebula -- SIMBAD is wrong, wrong, wrong.

Check out this page from the MASH catalogue:  http://vizier.cfa.harvard.edu/viz-bin/vizExec/.show?V/127A&G027.0%2b01.5.  Perhaps I mentioned this one to you before?

I made two observations 9 years back with my 18" ---  I noted the planetary wasn't symmetric around the central star (as you also commented).

18" (7/31/08 and 8/1/08): At 175x unfiltered a mag 13 star was visible and a small ill-defined halo was highly suspected surrounding the star knowing the exact location.  Adding an OIII filter, the halo brightened nicely and the edge sharpened to a 20" disc.  The involved star appeared offset to the north side.

For comparison, here are a few more observations ---

Alvin Huey (22" @184, 255 and 328x): Considerably faint round glow with defined edge with a very bright central star.   Estimated magnitude of the central star is about 11.5.  Not visible without filter.  Ultrablock brings it out pretty well and a similar response with O-III filter.  About 0.5' across.

Kent Wallace (20" @134X and 169X): could see the star superimposed on the northern side of the PN as shown in the SuperCOSMOS blue image. Using the O-III filter and averted vision, a blob forms on the southern side of the star. Good response to the O-III filter. Fair response to the UHC filter. No response to the H-Beta filter. The image is best at 169X. At 254X, the image isn't very good. Identified the field in the AP finder chart. This is a first known visual sighting.

Kent Blackwell (25"): Easy to find because of its involvement with an 11.4 magnitude star.   Even in bright moonlight I could still see it. Once I sighted the nebulosity with the filter I could see it without a filter. It responds so well to the OIII the nebula nearly outshines the involved 11.4 magnitude star.

-- Steve




7
Observing Reports / Re: First time Lake Sonoma 7/24/17
« on: July 25, 2017, 07:52:33 PM »
Glad to hear you had a good time at Lake Sonoma.  I've observed there on 150 nights and feel the skies are surprisingly good (generally SQM 21.3-21.45) -- particularly to the west of the meridian -- for so close to the bay area.

8
I plan to observe this upcoming week (July 18-22?), along with several other northern and southern California amateurs, at Grandview Campground at 8500 feet in the Pinyon Juniper slopes of the White Mountains, just a half hour paved drive from Big Pine into the Inyo National Forest.  It's roughly a 7 hour drive from Berkeley, but the skies can be magnificent.

If you're interested in more info, contact me at <astrogottlieb at gmail dot com>.


9
Rants and Off Topic / Re: Welcome Back Brad Franzella!
« on: July 13, 2017, 08:56:45 AM »
Yep, rain and clouds but we did have one night of viewing -- the first night, which on July 30th (Wednesday).  My notes say I looked at a number of Barnard dark nebulae.  In any case, a lot of fun.

10
Observing Reports / Re: Legitimate Peak observations
« on: June 29, 2017, 11:12:11 PM »
Fascinating list of pretty obscure summer targets!  The double to the south of STF 2606 is Ho 290, discovered by Herbert Howe in 1895 with the 20" Clark refractor at the Chamberlin Observatory in Denver.  The current separation is 3.5", which of course is quite easy, but the Delta is 3 mags.  Struve never observed it, but has the designation ADS 13628 (Aitken Double Star catalogue).

I've seen KjPn 1, but not 2 or 3 -- KjPn 2 is listed at V = 17.6 in SIMBAD, which is awfully faint, and I believe KjPn 3 is even fainter.  If you caught these, I'm pretty sure it would be the first visual observations!

Steve

11
Equipment Discussions / Re: Help Upgrading Argo Navis firmware?
« on: June 19, 2017, 07:24:09 PM »
I'm also interested in updating my AN firmware, as well as the Servocat firmware.  Has anyone performed this update?

-- Steve

12
TAC Visual / Re: Triple double with Cor Caroli
« on: June 19, 2017, 07:20:23 PM »
Cor Caroli was cleanly resolved at 25x using my 80mm finder and even 13x split the pair.  Here's another approach -- what's the lowest magnification to resolve this gorgeous duo?

-- Steve

13
Observing Reports / Re: Making the most of it from the Peak
« on: May 31, 2017, 08:33:59 PM »
Perhaps, but it's also possible he misinterpreted some scattered light around the central star as nebulosity.  I've observed LoTr 5 in the 48" and I wouldn't call it a "Very easy object" even in that scope.


14
Observing Reports / Re: Making the most of it from the Peak
« on: May 30, 2017, 09:14:44 PM »
Nice set of mostly bright galaxies, but that one planetary -- LoTr 5 -- is a nasty faint shell surrounding a bright central star!

Bob King called it "easy" in this Sky & Tel online article, but I disagree -- http://www.skyandtelescope.com/observing/hunting-giant-planetary-nebulae/

15
TAC Visual / Lake Sonoma OR from Saturday May 20th
« on: May 21, 2017, 01:52:49 PM »
I decided to go to head to Lake Sonoma yesterday afternoon (Saturday) as the predicted conditions were excellent.   Only two others showed up -- Matt Marcus and Shneor Sherman, which was surprising as this was the best weather in terms of temperature/humidity/wind, etc. that we've had in awhile.  It turned out to be a dark night with pretty good seeing.  I made a SQM reading of 21.45, which beats most locations close to the bay area, though the Milky Way wasn't that impressive, so the transparency wasn't ideal.

Unfortunately, we were interrupted for at least an hour and a half by a parade of cars/pick-up trucks that drove into the large Lone Rock lot every few minutes, apparently looking for the rowdy party that took place in the equestrian area just below Lone Rock.  There was also an unusually high amount of road traffic on Rockpile Road, so not a very relaxing evening.  Around 12:30 it finally quieted down and fortunately stayed that way.

One highlight was the type IIP supernova SN 2017eaw in NGC 6946 -- the appropriately named Fireworks Galaxy, which was discovered a week ago on May 14th.  It was easily visible (close to mag 12.5) in the halo of the galaxy, 1.0' west and 2.4' north of the center, and formed a wide pair with a fainter star.  This is the 10th supernova in the past century in the NGC 6946 (I believe I've viewed 4 of these) and it holds the record for the most prolific SN producer: SN 1917A, SN 1939C, SN 1948B, SN 1968D, SN 1969P, SN 1980K, SN 2002hh, SN 2004et, SN 2008S, and now SN 2017eaw.  It may still be on the rise -- in any case it was easy to see in Matt's C-8 and certainly a 6" (or smaller) will do the trick.  Check it out if you view in the next week!!

I also viewed Comet C/2015 V2 (Johnson) in Bootes, which was a bright 7th magnitude (visible in binoculars) and displayed a faint but obvious tail that extended through much of the 13mm Ethos eypeiece field.  It displayed a large coma and an intensely bright nucleus.  This is easy to find and well placed mid-evening, so another one not to miss.

As far as deep-sky objects, I took notes on about 3 dozen galaxies -- mostly working on two projects.  One is to pick up very faint companions to NGC galaxies.  The companions are sometimes in the IC, but often just carry a PGC designation.  The other project is galaxy mergers -- where two nuclei can be resolved within a single common halo.  A good example is NGC 5259, a faint galaxy in Canes Venatici, which I viewed around 1:30.  The second nuclei, labeled in this image as Holmberg 533B (Eric Holmberg studied double galaxies as part of his doctoral thesis in Sweden in the 1930's), was tough at 375x but definitely visible most of the time.

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