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A Hunt for Spiral Arms and Bars

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#1 Araguaia

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Posted 10 August 2019 - 01:51 PM

Tomorrow is likely to be my last session for a while.  The Moon will set at 3:20 AM, and the sky is very clear.  After that the Moon will be out most of the night, and by the time it starts to set early enough for an evening session, the smoke is sure to be covering the sky.

 

I decided it will be a stroll through bright(ish) spiral galaxies I haven't seen yet this season.  Most of them are to the SE, and will be fairly high only just before first light.  It will be a bit of a race to get them all in between about 4:30, when they'll start to get high enough, and 5:15, when the Sun will be 18 degrees below the horizon - astronomical twilight, it is said, though the other night I thought the sky to the NE was already washed out by 5:00 AM, mostly due to the zodiacal light.

 

The plan is:

 

- NGC 1300 at 4:15 (60 degrees alt) - should see the bar, hope to see at least a hint of the arms.

 

- NGC 1433 at 4:30 (45 degrees), a new target for me - it is said to show arms to the patient.

 

- NGC 1566 at 4:45 (35 degrees) - usually shows a nice loose S shape.

 

- NGC 1672 at 5:00 (30 degrees) - logged last season as a TIE fighter shape, with much detail.  It was a bit higher, but the sky might be more transparent now...

 

I'll start with Uranus while sipping coffee and waiting for the last moon glow to fade. Between moonset and 4:30 I'll warm up for spiral arms with M33 and NGC 1365, which I have already observed the past few nights, stroll around the Fornax Cluster for a bit, and probably have a look at the eery Eye of Cleopatra.   I'll close with the rising Orion Nebula, of course, and enjoy the reds and greens just to spite the deniers... grin.gif


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#2 KidOrion

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Posted 10 August 2019 - 02:58 PM

NGC 7479 in Pegasus is a classic barred spiral. 

 

NGC 157 in Cetus will also show some spiral structure.


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#3 Araguaia

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Posted 11 August 2019 - 07:57 AM

A beautiful session!  12" Dob, 30mm, 14mm, 5.5mm, and 3.5mm EPs.

 

After Uranus, I started the hunt for spirals with NGC 157 - thanks for the tip, KidOrion.  It was right in Dobson's Hole.  At 51x I found a bright oval, slightly teardrop-shaped.  At 277x it would show a core with averted vision, and when the core appeared so did a swirl pattern in the halo, going clockwise.  I couldn't hold it in direct vision but it was quite clearly spiral.

 

NGC 1300 showed a bright bar right away, and soon showed the fainter stubs of its arms as well.  Not as easy to see them as with NGC 1365 - about as hard as the arms of M101.

 

NGC 1433 was an elongated patch, which only showed a hint of wisps around it after prolonged observing at 277x and 435x.  The toughest arms of the night.

 

NGC 1566 was spectacular, just as I remember.  A bright extended core with a superimposed S, trailing off a long way.  Almost as evident as the arms on M51.

 

NGC 1672 took a few minutes of observing to show the TIE fighter shape - it was rather low in the sky.  It must be very nice seen from further south.

 

I ended with a look at M42, the Double Cluster, and the Pleiades, awash in zodiacal light.

 

Five face-on spirals, besides M33.  A few years ago, I would have never imagined that I could see arms in so many galaxies if I gave it enough time...


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