#155: A Few Useful Websites, and Messier 3

 I use a handful of websites to aid in my astronomy planning.  To me the most useful one is any weather app that shows past, current and future cloud cover.  I want to see for myself where the clouds are and what they are up to.  Astropheric is good, and their app is pretty decent, too.  Next in importance for me is Telescopius.  I use this to prepare myself for faint galaxy searches, drawing by hand the area around a faint object in the hopes of getting there easier with the scope.  My push-to computer gets me in the vicinity, but to pinpoint the exact location of a 14th mag. galaxy requires a lot more than being in the vicinity.  The site is also useful for providing info on the degree above the horizon an object is at any given time.  Those are my top two websites.  However, when I am preparing a new constellation to observe I use Stelle Doppie to prepare my double star list.  Users can customize which stars to try splitting (my way) or use their own prepared lists.  My 12" list of double stars often numbers in the hundreds for a given constellation (say Cassiopeia, for example).  Next I find Cseligman very helpful, especially when confusion arises regarding errors in the NGC or IC.  I also like to use TimeandDate to get my accurate moonrise and moonset times.  I use a host of other sites, but not as often as the ones above, which I find indispensable.

 

Moving on towards Messier 3 in this ongoing series, I should say here that I like to observe the area around bright deep sky objects to see if any other worthy sights are just a short hop away.  In the case of M 3, there is.  24' following M 3 sits faint gc 5466.  First seen in late July 1992, I was unable to see it earlier from suburban skies with my 8" Edmund reflector.  But from Lake Penage west of Sudbury in northern Ontario it was easily swept up at 36x.  It appeared as a large and faint round haze, with no resolution.  However, 59x and 72x showed some resolution with averted vision.  No bright center was seen; just a uniform dim haze.  At 112x the cluster was dimming and fading, with higher magnifications being useless.  Jump to early June 2013.  Looking at the specs this sounds like a showpiece (Mag. 9.2, 9').  It isn't, even in a 12" scope.  It is very faint, but very large.  The bigger scope resolves the cluster fairly well, and it was observed at 60x, 100x and 120x.  Stars were resolving well beyond the hazy ball itself, especially south.

 

Turning now to Messier 3 it was in late May of 1998 I viewed the globular cluster with the 8".  This is a real treasure of the sky!  Especially if one tackles the much fainter gc 5466 first.  M 3 is an amazing and brilliant object.  At 36x outliers were resolving.  At 59x dozens of stars, mostly outside the ball of bright haze, resolve.  At 112x stars were resolving to the core.  169x and 200x show countless stars, and a tantalizing sphere of unresolvable haze in behind.  This is a showpiece for 4" and higher!  

 

M3 (NGC 5272) is one of the finest globulars in the sky, and makes a very refreshing sight after viewing so many galaxies, my most frequent visual targets. Finding M3 is easy. Locate Arcturus, and then nearby Eta (just south preceding it, mag. 2.5). Make Arcturus and Eta the east-west baseline for a right-angle triangle, shooting north twice the distance of that baseline (see map: note M53 and M 64 are also shown, but are not part of this discussion). At a visual mag. of 6.3, even in binoculars M3 is impressive. It resolves nicely in a 6” mirror, and in my 12” at 170x I’m beginning to get that Hubble feeling. The main body spreads out over 18’, though outliers go well beyond. The brightest star is mag. 12.7, so in a really dark sky smaller scopes will partially resolve this cluster nicely.  This is a cluster not to be missed, enhanced greatly by its high declination.

 

 

There is also a small 13 mag. galaxy just preceding M3 (not on map) which I have not observed.  It will be added here in the future.

 

Messier 3.  Photo by Steve Mastellotto from the Windsor center of RASC. 

 

Mapman Mike

 

#45 Two Spring Globular Clusters

          Any seasoned observer knows that Spring is galaxy season.  The skies are rich with bright galaxies, and armed with a 6” telescope the best and brightest can be enjoyed.  With our club’s 14” scope (RASC Windsor), most of the fainter NGC list can be picked off, too.  Uranometria 2000 lists over 26,000 galaxies and/or galaxy clusters in its charts, a daunting task for any one person to observe or photograph.  Until summer constellations begin to rise later in the night, there is not much to see in the way of clusters.  In a future Spring post, I would like to discuss in greater detail some of the galaxy wonders of Leo, and not just the one famous triplet, but a number of other “triplets” as well.

            This time, however, I am turning to a pair of globular clusters, one of them a highlight of the entire flock.  Uranometria 2000 plots 170 globulars, including those inside the Magellenic Clouds.  I’m not certain how many are observable from northern latitudes, but it seems reasonable to assume that observing the entire viewable list is not too daunting a task.  We all know that the summer sky is crowded with globulars, though after seeing too many in short order they can tend to look somewhat similar, at least in smaller scopes. 

If you did not catch the recent Hubble view of M5 published in APOD on April 25^{th 2014} you should stop reading now and go take a look ("Astronomy Picture of the Day").  Hubble’s view of M5 is the perfect image of this object type, and the image we are all seeking when we go to the eyepiece, whether with a 6” mirror or a 36”.  I am convinced that globular clusters alone are responsible for most of us wanting bigger and bigger mirrors at our disposal.

            M5 is not well placed in early spring skies, but a worthy competitor is.  M3 (gc 5272) is one of the finest globulars in the sky, and makes a very refreshing sight after viewing so many galaxies.  Finding M3 is easy.  Locate Arcturus, and then nearby Eta (just south preceding it, mag. 2.5).  Make Arcturus and Eta the east-west baseline for a right-angle triangle, shooting north twice the distance of that baseline (see map, below: note M53 is also shown, but is not part of this discussion).  At a visual mag. of 6.3, even in binoculars M3 is impressive.  It resolves nicely in a 6” mirror, and in my 12” at 170x I’m beginning to get that Hubble feeling.  The main body spreads out over 18’, though outliers go well beyond.  The brightest star is mag. 12.7, so in a really dark sky smaller scopes will partially resolve this cluster nicely.

            By comparison, the second globular is much harder to see and resolve.  GC 5466 can be located 25’ following M3, and looks impressive enough on paper.  Its combined visual mag. is 9.2.  However, it is spread out over 9’ and the brightest star is only mag. 13.8.  In a great sky this one is barely visible in a 6” scope, and I have swept past it with the 12”.  Once located, it provides another wonderful lesson in interstellar distances.  In the larger scope the centre shows a slow burn, rather than the hot intensity of M3.  Resolution of stars is more ephemeral.  Patience is needed to begin to see the wonders of this large but very faint object.  Still, it is a gem and would be worth a trek to the club observatory’s 14” to see.  In fact, it would be better to begin with gc 5466, as our observatory scope will track right to it.  After observing the fainter object for a time with different eyepieces, moving to M3 will be guaranteed to give the viewer a rush.

            Amidst a night of viewing Spring galaxies, I always enjoy stopping for a break and viewing these two globulars.  Even after dozens of times I still enjoy the contrast and quiet spectacle they provide.

Mapman Mike

Monthly Summary #3: May/June 2013

     With one of the worst clear-sky time periods during new moon I have ever experienced, there almost was no report this time.  Then, finally, along came one clear night near new moon, and I found I would be able to write up a very brief report, at least.  Then came two more clear nights as the moon was waxing.  Now, finding those faint NGC objects from my area is never a walk in the park.  But when the moon is up high in the west, it makes the job even more difficult.  On that third clear night, to add insult to injury, the humidity was 85%.  It was like trying to look through an aquarium to see the deep sky!  Of course once the moon reaches first quarter, effectively ending my deep sky search for two weeks, along came some of the best night skies I have ever seen.  Four of them.  Sigh.

     Anyway, despite most of the gods on Olympus conspiring against astronomers in my area, I was able to add 14 new NGC/IC objects to my life list.  All, without exception, were faint to very faint galaxies.  Only one recorded object was a non-galaxy, the lone globular cluster in Bootes which I had observed years ago with the 8".  Some of these objects were not only very difficult to see, but also difficult to locate at all.  None of them projected enough photons into my eye to really impress me, so after tiring later on in the nights, I turned my eyepiece on some of the more splendid glories of the heavens.

     Here is a list of new objects added to my list.  12 are NGC and 2 are IC.  All but one are located in the vicinity of Arcturus, which became my home base for the three deep sky observing nights.

eg 5490-C:  Seen last month but not fully recognized as the partner to 5490.

eg 5492:  At mag. 12.8, one of the brighter objects this term.  A dim slash (1'.6 x 0'.4).

eg 5498:  Mag. 13.7.  Oval and very very faint, only seen with a.v.

eg 5508:  Mag.13.65. Within a very faint star cluster.

eg 5509:  Mag 13.95.  Paired with 5513 at 150x.

eg 5513:  Mag. 13.25.  Paired with 5509.  Not difficult.

eg 5518:  Mag. 13.65.  Occasional stellar core seen.

eg 5628:  Mag. 13.6.  Seen with a bright moon just west.

eg 5702:  Mag. 13.25.  Just a tiny bit north of 5710 and 11.

eg 5710:  Mag. 13.2.  Paired with much fainter 5711.

eg 5711:  Mag. 13.75. Both objects seen under a 5-day old moon.

eg 6646:  Mag. 13.  In Lyra.  2 IC galaxies nearby not seen yet.

IC-0982:  Mag. 13.25.  Paired with 983 near a bright star, north of 5490 and 90-C.

IC-0983:  Mag. 12.4.  Brighter pair member, easily seen.  Largest of the month.

gc 5466:  This large, very faint globular is a real tease.  Seen years ago with the 8" under ideal skies, a few stars could be resolved.  With the 12" I could not even see it at all from my backyard.  From my dark sky sight south of here, the cluster at first resembles a very large, very faint galaxy.  Then a few stars begin to resolve at low power.  Too much magnification spoils the view, as stars seem to be about mag. 13 and fainter.  I achieved resolution to the core at 150x, though certainly not a rich amount of stars.  And they are very, very faint.  Don't try this object in less than ideal conditions.  And just for fun, have a look at M 3 afterwards.

Mapman Mike