Towards the Galaxy’s Heart

2022-07-27 NGC 6520 OC in Sagittarius Stack_21frames_1835s
Image exposure:
30 minutes
Image size:
39.1 x 25.2 arcmin
Image date:
2022-07-27

There’s a lot going on in this image, so what are we looking at?

Constellation of Sagittarius in the general direction of the galactic centre
Milky Way star field, looking towards the central galactic bulge.
A countless star field of mostly old red stars, seemingly closely packed together.
◼ A dark nebula (Barnard 86) known as the “Ink Spot”

◼ Open star cluster (NGC 6520).
◼ Bright red star (HD164562) on the left of the dark nebula.

What’s that black blob?

Is it a hole in the star field? Are we peeking though a window to reveal an inky blackness beyond? Has Cosmic Focus Observatory discovered dark matter?

Actually no. That apparent “hole” is actually a dark nebula in front of the stars. It’s an opaque molecular cloud, an absorption nebula which is blocking our view of the numerous stars behind it.

To it’s right, the fifty bright blue/white stars of the cluster NGC 6520 contrast starkly against the immense background of red stars. Consisting of a group of recently formed hot young stars, it too, is located in front of the old red stars.

We know that stars are born in molecular clouds and astronomers assume that the open cluster of newly born bright stars formed out of part of the same molecular cloud. They are both reported to be at a similar distance of 5,500 light years.

Here is a cropped version of the same image, which shows remaining dark nebulosity near the open cluster which seemingly links to the Ink Spot on the left.

2022-07-27 NGC 6520 OC in Sagittarius Stack_21frames_1835s crop
NGC 6520 Open Cluster in Sagittarius & Barnard 86 Dark Nebula
Image size: 18.3 x 12.6 arcmin
(cropped)
2022-07-27

The star HD164562 seems to dominate and it looks like a whopper but (of course, you’ve guessed correctly) it is also in the foreground. It’s a ‘middle of the road’ K class star, a little cooler than our own Sun, with a magnitude of 6.7.

Cosmic Focus Observatory

The images were taken on my front driveway with the Schmidt-Cassegrain telescope which I’ve been using for the last ten months. I’ll be using it for a few more weeks before reverting back to my refractor, for wider field views.

Cosmic Focus Observatory
Meade LX-90 telescope on Skywatcher EQ6-R Pro mount
2022-07-27
Telescope:Meade LX-90 200mm Schmidt-Cassegrain
(deforked); 2000 mm f/l @ f/10.
Optics:Astronomik light pollution filter.
Mount & Guiding:SkyWatcher EQ6-R Pro mount.
Imaging camera:ZWO ASI 071 MC cooled.

Astrometry.net

Images © Roger Powell

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Cosmic Focus

ABOVE US ONLY SKY : amateur astronomy in australia

2 Comments

  1. The color makes it look like it’s a hole as opposed to something in front, so I’ll take your word for what I’m actually looking at . . . and, that’s a lot of stars. And here me thinking space is mostly empty.

    Liked by 2 people

    1. Those stars are not as close as they look but nevertheless as you get towards the bulge there are plenty more of them than there are here in the galactic suburbs. So when we look at other galaxies, they seem bright in the centre and tenuous out in the spiral arms.

      🙃

      Liked by 1 person

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