Small Wonders: Ursa Major
Posted 29 March 2006 - 07:09 PM
Posted 30 March 2006 - 11:38 AM
I also want to say, thanks for taking the time to write the Small Wonders. I can't tell you how many times I have used them as a nights guide.
Posted 30 March 2006 - 11:44 AM
Posted 30 March 2006 - 01:57 PM
How soon can we expect a PDF format on this one? I was hoping that you would include Palomar 4 as a REAL challenge item. I suppose, really, that it is TOO difficult. It happens to be my #1 prioirity target this spring.
Posted 30 March 2006 - 02:59 PM
I've attached a finder chart from SkyTools in a PDF format to this post. You can DL it if you like. I'll post a DSS image immediately following.
The following information is from SkyMap Pro 10
Information about Pal 4
Basic object information
Object name: Pal 4
Object type: Globular cluster
Apparent RA: 11h 29m 39s
Apparent Dec: +28° 55' 54"
Constellation: Ursa Major
Names and designations
Star atlas chart numbers
Herald-Bobroff Astroatlas: Chart C-30
Millennium Star Atlas: Charts 657-658 (Vol II)
Sky Atlas 2000.0: Chart 6
Uranometria 2000: Chart 106, Vol 1
Harris Globular Cluster Catalog Data
A catalog of parameters for globular clusters on the Milky Way, Harris W.E., Astron. J. 112, 1487 (1996, rev. 15 May 1997)
Names and designations
Cluster identification number: Pal 4
Distance from the Sun: 99.6 kpc
Distance from the galactic centre: 102.2 kpc
Posted 30 March 2006 - 03:05 PM
Ironically, I was just out Tuesday night looking at this object in my 18" - I had poor transparency that night. I used moderately high powers to make it out, and even with averted vision found it difficult - a mere haze with no central brightening. Via SkyMap Pro, the nearby marker star is GSC 1984-1301 and is listed at 13.87 mag.
A good resource on the PAL's is here:
This article was written by Barbra Wilson (who is a forum member here).
Posted 30 March 2006 - 04:03 PM
Posted 30 March 2006 - 05:24 PM
You're a wonderful tour-guide!
Posted 30 March 2006 - 06:19 PM
Posted 31 March 2006 - 12:54 PM
Looks as though I'm going to have to put my lens where my mouth (fingertips?) is! I DO plan to try it a bit later this spring, after Scott Horstman and crew finish my ROR observatory!
If I fail with the TMB, my newly ordered Discovery PDHQ 12.5" may allow me to pull my chestnuts out of the fire.
You all may wonder WHY this particular globular cluster: it is the most distant Milky Way object visible from mid-northern latitudes. The distance I have for it is 345,000 light years, second only to Arp-Madore 1 (AM 1). AM 1 is in Horologium--not visdible from my location. So far my distance record on globulars has been NGC 7006 in Delphinus. I still haven't bagged NGC 2419 as yet, but that WILL happen.
Thanks again, Tom, for sharing your knowledge with us.
Posted 31 March 2006 - 01:38 PM
And - You are most certainly welcome!
Now's the time to push for NGC 2419 (unless you want to wait till next fall). I've viewed this one several times in everything from a 4" to a 20" equipped with an I3. It was pretty much "just barely there" with the 4" and fairly resolved in the 20" w/ I3.
2419 is pretty cool too. It's about 300,000 light years away from us, twice as far as the LMC and is nicknamed the "Intergalactic Wanderer".
Posted 01 April 2006 - 12:00 PM
I've had some really spotty weather this year, and haven't had much observing time. I'm reluctant to set up the TMB 203 f/7 if there is any chance of precip or wind. I've sorta' relagated the observing duties to either my TOA 130 or my new Canon 15x50 IS binoculars. I should probably give 2419 a shot with the TOA. O'Meara was able to get it with the Genesis, so I should have a chance with 30 mm more aperture.
You are right, though about trying things. You just never know when you just might have a rare set of conditions that allow maximization of the aperture available.
Last night I went out at 21:00 to check the skies--it had been cloudy almost all day. Wonderful-it had cleared all except a low cloud bank over the western horizon, which was obscuring my worst horizon light dome. There was a brief window of opportunity, so I checked the sky with my new Sky Quality Meter: my best reading to date: 21.68 was my highest reading, and an average of 5 determinations was 21.65. By the time I started setting up, the clouds were scudding in too fast to do anything. That's the way it has been all year.
Keep up the Small Wonders, too. I enjoy them alot. I also have the SkyMapPro ver. 11. I happen to like it better than either of my 2 other software programs (Autostar and The Sky-Serious Astronomer version).
Posted 01 April 2006 - 04:47 PM
I should probably give 2419 a shot with the TOA. O'Meara was able to get it with the Genesis, so I should have a chance with 30 mm more aperture.
2419 isn't all that bad, really. You should be able to pull it down from a dark site with few problems in a 5" apo. I know a couple of other folks that have got it in 4".
Keep up the Small Wonders, too. I enjoy them alot. I also have the SkyMapPro ver. 11.
Thanks. I've missed writing them. I'm probably going to do fewer product reviews (only one a month or so) and concentrate more on these and the Behind the Scenes articles. I just got caught up in all the stuff several manufacturers sent.
I looked at SMP11 - at the moment I'm not too inclined to upgrade from version 10 - at least for what Chris lists. I'm tempted to just wait till version 12 or so. Are there any significant improvements you can think of that would make me want to upgrade?
Posted 01 April 2006 - 05:37 PM
Wishing clear skies for all,
Posted 01 April 2006 - 06:58 PM
Posted 01 April 2006 - 07:21 PM
Posted 01 April 2006 - 08:11 PM
So how many of these galaxies do you think I can see with my 80mm Megrez in the light polluted skies of the W burbs of Chicago? Hmmm - first I need a clear night, I guess. I'll let you know how I do.
Posted 02 April 2006 - 09:50 AM
(Ursa Major) ...and is itself an open cluster. Designated Collinder 285...
Learned something new #1. I did not know that.
some 32767 galaxies brighter than mag 20 (on a more realistic limit, there are 812 at mag 15 or brighter, and 56 brighter than mag 12), 7 Hickson groups, 327 Abell Galaxy Clusters, 641 quasars (MKN 421 @ 11h05, +38 deg 11 min and mag 13.5 is the brightest), two planetary nebula, 9 diffuse nebula, and one globular cluster (Palomar 4)
More stuff I did not know. The part about "9 diffuse nebulas" caught me by surprise. I had no idea UMa had that many nebulae. Learned something new #2.
...M108 and...M97 in the same frame...in low power wide field views...both can easily be caught in the same field of view.
Learned something new #3. M108 and M97 can be seen in the same 25x100 binocular field. Good to know.
M81 and 82 are a spectacular pairing of galaxies visible even through small binoculars.
From NELM 4.4 skies (my backyard), both of these objects are invisible...even on the darkest, moonless nights. It takes more than 100mm binoculars or a 60mm scope to bring these in through moderate-heavy light pollution.
...While a friend of mine in Arizona with access to a 30 inch telescope describes seeing red or pink (M81)...
Pink in M81!? Learned something new #4.
M101 is a large, loose face on object that can be decptively difficult in small telescopes. Keep in mind when searching you are looking for a large object - around 2/3 the size of the full moon, but the surface brightness is very faint so keep your eyes peeled for a gradual lightning of the sky background.
Something I tend to forget since I am a total noob when it comes to bagging galaxies. I'm a cluster and nebula freak, so sometimes I forget how BIG galaxies are and how this effects their Surface Brightness (Sb) ... thanks for the reminder!
So I learned 4 new things, got a good reminder/tip, and now I have some good little finder charts for UMa.
Thanks again Tom! I have a space on my bookshelf reserved for the printed edition of Small Wonders when you get it published.
Clear dark skies to you...