M33...Triangulum or Pinwheel???

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Boomer12k
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M33...Triangulum or Pinwheel???

Post by Boomer12k » Fri Sep 28, 2018 7:30 am

Thanks for visiting... this is my shot of M33... My Meade Autosuite software calls it.... "Pinwheel Galaxy"...But it is also called "The Triangulum Galaxy"... I guess both are correct.

This is 14, 30 second shots with my DSI II color camera, through my Celestron Evolution 6. I had a devil of a time finding the darn thing...wider field shots show a "notch" shaped nebula...or something. I found that...but could not find M33...I finally did a precision GOTO and saw these "Y" shaped stars...I had to look at a picture of it to tell that I was looking at nearly the center of the galaxy...it is so large, even my six inch can't take in the whole thing... not even HALF... but you can see some dust lanes, and star areas... and I thought it was pretty cool for my first time...

click picture for larger view...

It is hard to tell what you are looking at...with more exposures it might be better...I will try again. But the 3 stars in a triangle is the central core area... some of the "dark blotches" are camera faults, 10 year old camera now....but the dark areas around the 3 center stars are dust lanes. I darkened it up a bit for some better contrast...it was a near full moon out tonight as well...plus, I am in a mobile home park, with a yard light right in front of my scope about 8-9 feet away... not a good setup...and still got something.

Well...hope you liked it...
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Joe Stieber
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Re: M33...Triangulum or Pinwheel???

Post by Joe Stieber » Sat Sep 29, 2018 4:51 pm

I've tried to view your image Boomer, but unfortunately, the link is dead using both Firefox on my Windows laptop and Safari on my iPad. It currently indicates 35 views when I move my mouse cursor over the link, but I see that it records even the unsuccessful clicks (a number of which are mine). Oh well.

Indeed, the name Pinwheel has been applied to both M33 and M101 in the past since both of these face-on spirals do resemble a pinwheel. In recent years, Pinwheel has been applied more exclusively to M101, while M33 is now mostly called the Triangulum Galaxy. However, there's no formal naming authority for deep-sky objects, so current usage still varies for M33.

Both galaxies are relatively bright based solely on magnitude, but because they're face-on and large, the light is spread out, so surface brightness (magnitude per square arc second) is low. M33 is brighter, around magnitude 6, but I've never seen it with unaided eyes (and probably never will from here in New Jersey, where even the darkest sites just aren't dark enough for my eyes to see it). I wouldn't even try observing M33 under a nearly-full moon, let alone from a site with yard lights!

However, in NJ on clear night at a "dark" site, M33 is a fairly easy binocular object, and because of the low surface brightness, not as easy to spot in a scope (using just a reflex finder). However, a couple of weeks ago, we had a rare, exceptionally clear night, and after moonset with a friend's 12-inch scope and careful scrutiny, we could see dark and light bands of its spiral structure and ultimately, a couple of the NGC objects in it (604 was easy while 592 was more difficult).

Alan Whitman's interesting article from S&T magazine a few years back, Digging Deep in M33, has been posted online. There's a link to the PDF here...

https://www.skyandtelescope.com/observi ... ep-in-m33/

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Joe Stieber
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Re: M33...Triangulum or Pinwheel???

Post by Joe Stieber » Sat Sep 29, 2018 5:19 pm

That's weird. I posted my reply, and then the image appeared in the attachment box and the link to a larger version worked, but only in Firefox on the laptop, and only briefly. Before I could get a good look, it disappeared and could not be regenerated. I saw the Y-shaped asterism Boomer mentioned, but not for long enough to establish any context. Go figure!

I wonder if it will appear again after this reply?

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Joe Stieber
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Re: M33...Triangulum or Pinwheel???

Post by Joe Stieber » Sat Sep 29, 2018 6:12 pm

The image (and a working link to the larger version) reappeared after I posted my second reply and I was able to save a copy to look at more closely. I still don't understand what's happening with the link; regardless, I was able to match a couple of things in the image with other online images and the object guides in the S&T article.

Just above the base of the "Y" in Boomer's image, there's a triangle of stars. That's very close to the center of M33, marked by an adjoining fuzzy area in the image. Near the top, about a quarter to a third of the way across from the right edge, I believe the small fuzzy spot is NGC 595. Indeed, the field of view is too narrow to capture the full extent of M33 as Boomer noted, but it's a first try -- under less-than-ideal conditions.