salutations celestial sight seers I'm David fuller welcome to eyes on the sky
what's up this week well how about a top 20 globular cluster
that's almost right overhead for a lot of us and isn't that hard to find
because it's fairly close to one of the brightest stars in the night sky I am
talking about Messier 56 which is a rather interesting globular I think it
gets overlooked a little bit in favor of things like M 22 or M 13 but here are
some cool facts about it it's about 33,000 light years away it's 84 light
years across so the light takes over a full average human lifetime to go from
one side to the other it is 13.7 billion years old so it's nearly the age of the
universe itself now here's what is also interesting
about that because it's so old and it also has a very low metals content which
means it doesn't have a lot of elements other than hydrogen and helium in it
they are some of the oldest stars out there so when you go to look for this
cluster you'll be looking at some of the oldest stars that exist so how do we
find this cluster well I'm gonna back out here and show you where we are in
the sky when we take off some of these markers we don't have quite so many
labels floating around here we can look and see we've got the summer triangle
so there's Vega there's Deneb there's Altair we are generally looking just
about overhead somewhat east ish I lost my cardinal point somehow
cardinal points by the way you can turn on using that and then there they are
so east to overhead at least for where I am at 40 degrees north latitude Vega is
one of the brightest stars in the sky it's a zero magnitude star so kind of
hard to miss especially when it's overhead like that where Messier 56 is
is kind of halfway in between a halfway point so if we look
Vega and Altair about halfway we can find Albireo which on its own is an
amazing double star to definitely take a look at but if you can see Albireo then
m56 is just about halfway in between there
I'm not sure I'm gonna be able to pick it out and it's right there
excuse me it is halfway in between actually where Albireo is and this star
right there which is Sulafat so we need to get to Sulafat at minimum just
to be able to help us find this so let's focus in on Vega we'll go to the
binoculars and in binoculars we can see quite a few things there's the
double-double and if we move this direction just a little bit we start to
see the top part of where the parallelogram is so Nasr al Waki and
along with Delta Lyrae Delta Lyra is actually a very cool colorful double
star to take a look at but we want to go down into that parallelogram shape and
I'm gonna bring that up really quickly with our constellation lines and you can
see there's our parallelogram and of course in between Sheliak and Sulafat
is the ring nebula which a lot of people are apt to try and find I've covered
that a couple times here with eyes on the sky but we're gonna go a little
further than that so we're gonna use Sulafat which is your furthest point
away from Vega in Lyra so when you have Sulafat and this is where it's
really gonna help to have a magnified finder scope because we're gonna be
using fifth and sixth magnitude stars to point the way to find our globular
clusters so with Sulafat there you can move in this direction because remember
we're halfway in between there in Albireo if you still have Sheliak and
Sulafat in your field of view you've already got Messier 56 there so you know
that it's there and you can even see the spot that it's at now it's just a matter
of looking at the shapes and determining how we find that so how do we
stop there well these stars this one and this... oops, excuse me - this one I'm gonna take off
the line so we don't get too confused and think that those lines appear in the
sky cuz they don't so these are largely fifth magnitude stars this one is
actually right here that's a sixth magnitude star but if we head back down
here we got another fifth this one right here is a five point six so it's were
technically a six magnitude star and then this one is five point nine so a
six magnitude star but look at the shape that that forms and I'm gonna use my
measuring tool to kind of show you this so there's this and then there's this it
goes outside of Sulafat so we got this nice kind of arrow shape thing with sula
fat off to the side but these are not very far there's only like two degrees
or so but if we take this line of stars the one that's further away from Sulafat
and then just kind of continue on that star right there that's what we're
aiming for so we can find these other ones because they're all gonna be about
the same now by the way sulla that's about a third magnitude star so it's
definitely a couple points brighter but what you should be able to see the fifth
and sixth magnitude stars to most finder scopes in most locations so we're
looking for that star right there which is a five point nine magnitude star very
similar to this one I would definitely suggest that you have a large field of
view or go just a little farther when you are centering things because if you
don't and we don't do that and we kind of zoom right in even if you've got a
one degree field of view watch what happens so there's a one degree field of
view and fifty six is just on the outside edge of that so if you're not
perfectly centered it might look like it's actually gone a little outside of
there and then you may be like well but Dave where's m56 I didn't see it so just
go just a little further than that star if you need to if you can't see the
cluster in there go a little further that way you'll have that cluster in the
field of view with this star at the same time and by the way that looks like it
appears to be a double star so we got a five point nine right
and the one right next to it is a ten point six so you may be able to split
those so look for M56 that way and then push up your magnification I've got
this at 200 times your telescope may not support that depending on how large your
aperture is so if you've got anything under a four inch or 100 millimeter
aperture don't go up to 200 times you're gonna want to limit that to about 50
times per inch of aperture or less depending on your sky conditions but and
remember that that's really the practical max maximum on that go less
than that especially if it looks better if you're only at 25 30 40 times
magnification that's okay but larger aperture is gonna show you more stars
because this particular cluster does have some 13th magnitude stars you won't
see those probably in a 60 70 80 millimeter telescope but if you have
something like 6 or 8 or 10 inch telescope you have a good shot at
resolving some of those brightest stars in this cluster and it's one of a very
very old set of stars out there in the universe that you can see from your
backyard so check it out this week while we have the moon out of the way M56
is a superb globular cluster to take a look at that's all for this week keep
your eyes on the sky and your outdoor lights aimed down so we can all see
what's up I'm David fuller wishing you clear and dark skies
you