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Constellation Crux and Coalsack Nebula (C99) (Re-Work)

In April 2021 I posted here a new version of a capture made in July, 2020. Well, I was not entirely happy.

Then, I decided to do a new version. This means that the picture I’m posting today is at least the 3rd version of the same data. Ok, ok, sorry. I won’t be stalling. Here is the new (And hopefully the last) version:

Crux and Coalsack Nebula (C99)

Also, I made an annotated version, with the astrometric solution. What are your thoughts?

Crux and Coalsack Nebula (C99) with astrometric solution
Crux and Coalsack Nebula (C99) with astrometric solution

EXIF

This is the equipment I used to capture this image:

No autoguiding this time!

And the lights:

  • 142x30s (Total of 1.2h of exposure);
  • ISO 1600;
  • Bortle 6 skies;
  • Moon: 81% illuminated;
  • No darks, flats or BIAS;
  • Data captured on July 9, 2020;
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Constellation Crux and Coalsack Nebula (C99)

This image of the Constellation Crux and the Coalsack Nebula (C99) uses one of the first light captured with my Canon T6i, back in July, 2020, with a 135mm lens. I just totally forgot to proccess this one! Shame on me.

These are two objects really close on to each other on the southern hemisphere. And although they’re very close to each other, they’re also very different. Let’s talk about them?

The Crux constellation

The constellation Crux is one of the easyests constellations we can identify on the southern hemisphere. In a shape of a crux (You don’t say??), it is located inside the constellation Centaurus and next to constellation Carina.

The alfa of the constellation Crux is also knowed as Acrux or “The Magellanic Star”. It is very bright and easy to identify. Through a telescope, though, Acrux shows itself as a incredible double star.

On the left arm of constellation crux is located the Jewel Box, a very beautiful open cluster, visible with naked eyes but gorgeous through a telescope or a binoculars.

The Coalsack Nebula (C99)

The Coalsack Nebula, or Caldwell 99, is the biggest dark nebula of the entire sky. On a dark sky location, is visible through naked eyes, obscuring the milky way stars next to the constellation Crux.

When I say that it’s the biggest dark nebula, is because it is big. Really big. Even through my 135mm lens I can’t get it’s full extension. And it’s so big as it’s beautiful.

My first capture with the Canon T6i

When I bought my Canon T6i (Canon 750D), the skies cleared up for 1 or 2 days, and I managed to capture about 1h of the constellation Crux and Coalsack Nebula. But, for some sort of a reason, I totally forgot to proccess those lights captured.

Some time later, with clouds on the sky for months, the abstinence made me search for some light frames to process, and bang! I found 142 frames of 30 seconds with my Nikon 135mm f2.8 Ai.

After some time processing it, here is the result:

Constellation Crux and Coalsack Nebula (C99) at 135mm
Constellation Crux and Coalsack Nebula (C99) at 135mm

What are your thoughts?

EXIF

This is the equipment I used to capture this image:

No autoguiding this time!

And the lights:

  • 142x30s (Total of 1.2h of exposure);
  • ISO 1600;
  • Bortle 6 skies;
  • Moon: 81% illuminated;
  • No darks, flats or BIAS;
  • Data captured on July 9, 2020;
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Crux and Coalsack Nebula (C99)

The Crux constellation and the Coalsack Nebula (C99) are so close to each other that we can shot it through a 135mm and a cropped APS-C sensor.

And I finally did it! Let’s see how it ended.

The Crux constellation

The Crux constellation is probably the most known constellation of the southern hemisphere, and it’s easy to understand why. There are 4 stars, being the less brighter yet on magnitude 2.75, and disposed on a “cross” shape very easy to locate.

This constellation is full of surprises. Just to the left of the star called “Mimosa” (Beta Crucis) is the Jewel Box (NGC 4755), a beautiful, bright open cluster with stars of many colors.

The star Alfa Crucis, also known as “Magellanic Star”, is the brightest one, with 0,8 mag. This is also a multiple stelar system, with at least 3 stars.

The Coalsack Nebula (C99)

I don’t know why, but I just love dark nebulas. And the Coalsack is awesome! C99 is the biggest one seeing from earth, with dimensions of 7×5 degrees! It is HUGE!

I first discovered C99 a few years back, while I was on the firsts steps with astrophotography. I pointed my D5000 to the Crux with a tripod and toke some 15s shots. When I saw this huge shadow I couldn’t believe.

The picture itself

Shot it was pretty easy, to be fair. I started just after the sunset, but the first 4 frames was lost due to the INTENSE traffic of artificial sattelites. I should have thinking on that, right?

Then I made more 96 frames of 60 seconds with my D5000 and my Nikon 135mm f2.8 at f4.

This was the result:

Crux and Coalsack Nebula (C99)

Setup:

Nikon D5000
Nikon 135mm f2.8 AIs at f4
iOptron CEM25P

Exif:

96 x 60s ISO 400

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Conjunction of the Moon and Venus

I’m a simple guy, with some rules in life. Equalizate wine and beer. Don’t be a douchebag. Go sleep late. Don’t wake up sooner than the needed. Don’t miss any astronomical ephemerid, specially a conjunction of the Moon and Venus.

On June 19 I woke up at 5h30am just to shoot the conjunction of the Moon and Venus, in a clear conflict between my precious rules. My intention was to shot this ephemerid with my Long Perng S400M-C 66mm f/6 refractor , but the moon was to low in the sky to be reached by my iOptron CEM25P equatorial mount. My setup kept resting. Then I decided to give a try to my Nikon Nikkor 135mm f2.8 Ai.

How lucky am I? A lot. There was some beautiful clouds near the moon, which gave to the picture a fine touch of colors.

Here it is:

Conjunction of the Moon and Venus on June 19
Conjunction of the Moon and Venus on June 19

Setup:

Exif:

  • ISO: 200
  • Exposure: 1s
  • F-stop: 4

The Conjunction of the Moon and Venus was a beautiful event. The moon was a little more than 2 degrees from Venus, and just to the right was the Taurus constellation.

To give a final touch of beautifulness, the earthshine on the moon was awesome, and I managed to shot it right.

I hope you liked it!

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Eta Carinae (NGC 3372) in wide angle

Finally, on January 7, I was able to try my “new” old Nikkor 135mm f2.8 AI, that promises to be a great wide angle lens. I chose as a target Eta Carinae Nebula, or NGC 3372.

This nebula is one of the most beloved targets of the south hemisphere. It is located on the Carina constellation, and just the main nebula itself (NGC 3372) have 2 degrees of aparent size. It is huuuuuge!

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