Paddy
07-10-2012, 03:02 PM
Due to the ongoing nature of my obsession with the Magellanic Clouds and encouraging other folk with scopes to become similarly obsessed, I present my latest project - cluster hopping tours of the Clouds.
This is no.1, the northeast section of the SMC. I'd appreciate any feedback about the clarity and usefulness of the "tour" instructions. I will be loading the tours onto the site as well.
Charts can be downloaded at
cloudsofmagellan.net.au (http://cloudsofmagellan.net.au/)
SMC Tour #1 – Northeast
As the SMC changes it’s orientation as it circles the South Celestial Pole (SCP), I will us the terms preceding (p) and following (f) instead of West and East respectively. Preceding is the side of the field of view that objects move towards, following is the side they move from. I use the term North to mean away from the pole and South to mean towards the pole.
It will also help if you know the field of view of your eyepieces. This will help you find the angular distance between the object in minutes. If you’re not familiar with how to calculate this, it is the apparent field of view of your eyepiece (eg 80 degrees for a Nagler) divided by the magnification in your scope and multiplied by 60 to give the result in minutes. The magnification is the focal length of your scope divided by the focal length of the eyepiece.
This first “tour” covers objects in the north east (Nf) area of the SMC. A magnified finderscope will be very helpful in getting started, but otherwise a wide-field eyepiece should suffice. These notes have been made using a 16” F4.9 telescope under dark skies. Some of the fainter objects may not be visible using smaller scopes or with light-polluted skies. A 10-12” scope under good conditions should be enough to see just about all of these objects and an 8” will see most.
SMC charts 1 & 2 from cloudsofmagellan.net.au cover the objects in this tour.
These descriptions don’t include observations with a nebula/UHC filter. As many objects include emission nebulae, they are well worth viewing with filters as well as without.
Getting started. If you look at the SMC with a magnified finder or binoculars, you will see that the brighter parts of the galaxy look a bit like a comma, with the tail to the east (following) and the round smudge of 47Tuc to the north of the head of the comma. Looking at the tail with a finderscope, you will see 2 bright knots. Centre the scope on the innermost (preceding) knot. This is our starting and reference point, NGC 346. If you’re using a low power eyepiece, you will find a p-f string of objects in the tail of the SMC, most likely the smallest bright one at the p end is NGC 330. Centre your scope on the one to the f side and you are at NGC 346.
NGC 346 is a complex open cluster and emission nebula, reminiscent to me of a barred spiral galaxy in appearance. There is a 5’x2’ N-S central bright core embedded in a circular disc which is itself embedded in a 6’ N-S x 10’ p-f fainter haze, which is Henize emission nebula N66. NGC 346 is the largest and most active star-forming region in the SMC, as NGC 2070, the Tarantula nebula, is the most active star forming region of the LMC.
25’ f of NGC 346 is NGC 371, another large open cluster and emission nebula, not quite as bright as NGC 346, but still very obvious in a magnified finder as the bright knot just following NGC 346. It looks to me about 7’x12’ and is littered with resolvable stars.
10’ f of NGC 371 is the smaller and fainter, but again still quite bright, is NGC 395 another open cluster and emission nebula which looks about 3-4’ across. More challenging for smaller scopes is emission nebula IC 1624, a small but distinct glow 3’ S of NGC 395 and following a bright foreground star.
Come back to NGC 371, the second bright nebula that we visited. 7’ to the south of it is a N-S line of 3 stars. Just preceding this line of stars is the small glow of open cluster Kron 50, which forms the apex of a triangle with the row of 3 stars as the base.
Now return to NGC 346, our starting/reference point. You might want to have chart 2 ready. 30’ to the S-p of NGC 346 is the lovely, very bright small open cluster NGC 330. This is one of the SMC’s gems – a 2’x1’ lens shape of myriad tightly packed and still resolvable stars. Draw a line from NGC 330 back to NGC 346 and about halfway along and 2’ to the north of the line is the faint, small glow of open cluster Lindsay 56.
Come back to NGC 346 again. 14’ to the S is a flattened triangle of three small round glows, the apex of the triangle to the p side. The brightest of the 3 and closest to NGC 346 is IC1611, the next brightest (the apex) is IC1612 and the one furthest from NGC 346 is Kron 42. All of these are open clusters.
Get chart 1 out again.
From NGC 346, return to NGC 371. Imagine a line drawn from the centre of NGC 371 through the fainter, following NGC 395 and extend it for 25’ where you will find a bright foreground star. 10’ to the north of this star is the very round small glow of open cluster NGC 411. 10’ following the aforementioned bright star and forming a triangle with the star and NGC 411 is the very faint NGC open cluster NGC 412. This may well be beyond small scopes and poor skies. Also on the faint side is the larger 4’ open cluster Lindsay 84 which forms the S apex of a triangle with NGCs 395 and 411 as the base. Lindsay 84 is a soft glow with a brighter centre and several resolved stars.
Come back to NGC 411. 20’ Np is a bright foreground star. A further 25’ Np is the 3’ dia. circle of open cluster NGC 361, just before another bright foreground star.
This is no.1, the northeast section of the SMC. I'd appreciate any feedback about the clarity and usefulness of the "tour" instructions. I will be loading the tours onto the site as well.
Charts can be downloaded at
cloudsofmagellan.net.au (http://cloudsofmagellan.net.au/)
SMC Tour #1 – Northeast
As the SMC changes it’s orientation as it circles the South Celestial Pole (SCP), I will us the terms preceding (p) and following (f) instead of West and East respectively. Preceding is the side of the field of view that objects move towards, following is the side they move from. I use the term North to mean away from the pole and South to mean towards the pole.
It will also help if you know the field of view of your eyepieces. This will help you find the angular distance between the object in minutes. If you’re not familiar with how to calculate this, it is the apparent field of view of your eyepiece (eg 80 degrees for a Nagler) divided by the magnification in your scope and multiplied by 60 to give the result in minutes. The magnification is the focal length of your scope divided by the focal length of the eyepiece.
This first “tour” covers objects in the north east (Nf) area of the SMC. A magnified finderscope will be very helpful in getting started, but otherwise a wide-field eyepiece should suffice. These notes have been made using a 16” F4.9 telescope under dark skies. Some of the fainter objects may not be visible using smaller scopes or with light-polluted skies. A 10-12” scope under good conditions should be enough to see just about all of these objects and an 8” will see most.
SMC charts 1 & 2 from cloudsofmagellan.net.au cover the objects in this tour.
These descriptions don’t include observations with a nebula/UHC filter. As many objects include emission nebulae, they are well worth viewing with filters as well as without.
Getting started. If you look at the SMC with a magnified finder or binoculars, you will see that the brighter parts of the galaxy look a bit like a comma, with the tail to the east (following) and the round smudge of 47Tuc to the north of the head of the comma. Looking at the tail with a finderscope, you will see 2 bright knots. Centre the scope on the innermost (preceding) knot. This is our starting and reference point, NGC 346. If you’re using a low power eyepiece, you will find a p-f string of objects in the tail of the SMC, most likely the smallest bright one at the p end is NGC 330. Centre your scope on the one to the f side and you are at NGC 346.
NGC 346 is a complex open cluster and emission nebula, reminiscent to me of a barred spiral galaxy in appearance. There is a 5’x2’ N-S central bright core embedded in a circular disc which is itself embedded in a 6’ N-S x 10’ p-f fainter haze, which is Henize emission nebula N66. NGC 346 is the largest and most active star-forming region in the SMC, as NGC 2070, the Tarantula nebula, is the most active star forming region of the LMC.
25’ f of NGC 346 is NGC 371, another large open cluster and emission nebula, not quite as bright as NGC 346, but still very obvious in a magnified finder as the bright knot just following NGC 346. It looks to me about 7’x12’ and is littered with resolvable stars.
10’ f of NGC 371 is the smaller and fainter, but again still quite bright, is NGC 395 another open cluster and emission nebula which looks about 3-4’ across. More challenging for smaller scopes is emission nebula IC 1624, a small but distinct glow 3’ S of NGC 395 and following a bright foreground star.
Come back to NGC 371, the second bright nebula that we visited. 7’ to the south of it is a N-S line of 3 stars. Just preceding this line of stars is the small glow of open cluster Kron 50, which forms the apex of a triangle with the row of 3 stars as the base.
Now return to NGC 346, our starting/reference point. You might want to have chart 2 ready. 30’ to the S-p of NGC 346 is the lovely, very bright small open cluster NGC 330. This is one of the SMC’s gems – a 2’x1’ lens shape of myriad tightly packed and still resolvable stars. Draw a line from NGC 330 back to NGC 346 and about halfway along and 2’ to the north of the line is the faint, small glow of open cluster Lindsay 56.
Come back to NGC 346 again. 14’ to the S is a flattened triangle of three small round glows, the apex of the triangle to the p side. The brightest of the 3 and closest to NGC 346 is IC1611, the next brightest (the apex) is IC1612 and the one furthest from NGC 346 is Kron 42. All of these are open clusters.
Get chart 1 out again.
From NGC 346, return to NGC 371. Imagine a line drawn from the centre of NGC 371 through the fainter, following NGC 395 and extend it for 25’ where you will find a bright foreground star. 10’ to the north of this star is the very round small glow of open cluster NGC 411. 10’ following the aforementioned bright star and forming a triangle with the star and NGC 411 is the very faint NGC open cluster NGC 412. This may well be beyond small scopes and poor skies. Also on the faint side is the larger 4’ open cluster Lindsay 84 which forms the S apex of a triangle with NGCs 395 and 411 as the base. Lindsay 84 is a soft glow with a brighter centre and several resolved stars.
Come back to NGC 411. 20’ Np is a bright foreground star. A further 25’ Np is the 3’ dia. circle of open cluster NGC 361, just before another bright foreground star.