April 2021 DSO Challenge

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April 2021 DSO Challenge

#1

Post by kt4hx »


Since I do not have any access to the first southern object from my mid-northern latitude, I thought I would go ahead and post one of my best observations of the Eta Carinae Nebula more formerly known as NGC 3272. This was from a suburban location at around 5° south latitude using my 4.5 inch f/4.4 newtonian OTA. This particular evening there seemed to be much better transparency than was typical at that location.


NGC 3372 (Carina, emission nebula, mag=3.0, size=2.0°):

Just north of IC 2602 I of course located this amazing field with the 10x50 binoculars. Rich in nebulosity and clusters, it is, in my view, the premier bright nebula in the sky. As much as I love the Orion Nebula (M42), I still have a total preference for this delightful object. At 20x it was an elongated glow of varying intensity, with numerous small knots of stars within and without. The transparency in its direction seemed pretty good for here and that low to the horizon (about 32° elevation).

I brought out the DGM NPB filter to blink between eye and eyepiece, and the bright field came alive with nebulosity. It was large and one could make out the bold dark lanes between sections of the broader nebular structure. The gaseous clouds themselves seemed almost 3-D in appearance, with a decided curdled, turbulent appearance as the eye moved over them. Whereas I find M42 to be a delicate wispy nebula, I find the Eta Carinae Nebula to appear dense and uneven, which gives it a depth of field, seeming almost alive to the eye. They are both absolutely stunning objects, but to my eye nothing alike visually. They should be celebrated visually for their differences and what each brings to the table, observed slowly in order to get the most out of their respective presentations.



I hope to re-visit the other two southern objects and the Leo Triplet using the 17.5 inch at the dark site sometime this coming week. NGC 3132 in northern Vela culminates at a lowly 11° above the southern horizon, so that one will be a bit tougher, but should be doable. So I hope you all will get out there and pursue this month's targets and post your reports here as a new thread in this sub-forum. Hope to see you out there friends. :)
Alan

Scopes: Astro Sky 17.5 f/4.5 Dob || Apertura AD12 f/5 Dob || Zhumell Z10 f/4.9 Dob ||
ES AR127 f/6.5 || ES ED80 f/6 || Apertura 6" f/5 Newtonian
Mounts: ES Twilight-II and Twilight-I
EPs: AT 82° 28mm UWA || TV Ethos 100° 21mm and 13mm || Vixen LVW 65° 22mm ||
ES 82° 18mm || Pentax XW 70° 10mm, 7mm and 5mm || barlows
Filters (2 inch): DGM NPB || Orion Ultra Block, O-III and Sky Glow || Baader HaB
Primary Field Atlases: Uranometria All-Sky Edition and Interstellarum Deep Sky Atlas
---------------------------------------------------------------------------
"Astronomers, we look into the past to see our future." (me)
"Seeing is in some respect an art, which must be learnt." (William Herschel)
"What we know is a drop, what we don't know is an ocean." (Sir Isaac Newton)
"No good deed goes unpunished." (various)
Some people without brains do an awful lot of talking, don't you think?” (Scarecrow, The Wonderful Wizard of Oz)
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Re: April 2021 DSO Challenge

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Post by kt4hx »


Okay friends, we did get over to the dark site yesterday (06 April) for some observing. I was able to turn the 17.5 inch all the Leo Triplet and then NGC 3132 and NGC 3115. NGC 3132 was far and away one of the most difficult observations I have made from the dark site as it was only about 9° above the horizon. I had the seat of my Starbound chair way, way down and was down on one knee some as well. The scope was so low that I could not utilize the 21mm Ethos because its weight made the scope take a nose dive when it was almost horizontal. Unfortunately I had left my ES 82 24mm and 18mm EPs at home, so I had to start with the 13mm Ethos (152x). But that was okay as I knew the field where to find the planetary and it was more a matter of if it cleared the ridge lines miles to the south in the valley. Anyway, long story long, here is who it went as I re-visited these objects with the big eye in the sky! :) The remainder of my report (work in progress) will be filed in the Reports forum.


Messier 65 / NGC 3623 (Leo, barred spiral galaxy, mag=9.3, size=9.8’x2.9’, SBr=12.8):
Since some of my intended targets were still lurking near or behind the big tree at the southern end of the property, I needed to kill some time. So I began with the northern objects from the April TSS Monthly DSO Challenge. Aiming the scope at mag 3.3 Theta Leonis (Chartan), I then slipped south while viewing through the 8x50 RACI. I quickly found 73 Leonis (mag 5.3) just over 2° to the SSE. In the same view I could easily see mag 7.1 HD 98388 to its east. This star lie along the western side of the triangle formed by the Leo Triplet. South of the star I could just make out the presence of M65 in the finder as a tiny and very dim diffuse knot.

Moving to the eyepiece (94x) the triplet was seen easily all in the same 1.1° TFOV. M65 was a large and bright thin ellipse oriented north-south displaying an inner lens of brightness anointed with a stellar core. Its disk seemed uneven in illumination as the eye moved across its face. Moving to 152x the sense of a curdled visual affect seemed more noticeable and the northern side of the disk seemed slightly brighter than the southern portion. Taking a look at 199x, I picked up a subtly brighter section within its outer arm near the northern tip of the visible envelope. This galaxy was quite fetching in the 17.5 inch, and I wasn’t done yet!

Messier 66 / NGC 3627 (Leo, barred spiral galaxy, mag=8.9, size=9.1’x4.2’, SBr=12.7):
Sharing the same FOV with M65 and just to its east, I now concentrated on M66. It was slightly more apparent in the RACI view. Taking my first look at 94x, it presented a bright and large oval that was thicker in breadth than was M65. Similarly it was oriented north south and It seemed more evenly illuminated initially than did M65. Like the previous galaxy, it also sported a bright inner lens with a stellar core set within it. A 9th mag field star lay in close attendance to its northwestern edge. Checking it out with 152x it now appeared more uneven in illumination across its envelope. The southern portion of the disk seemed more extended than the northern, and it also seemed to be subtly hooked toward the southeast, inferring its spiral structure. There also seemed to be a tiny knot of brightness just north of the core, likely an HII region. Going ahead to 199x, the sense of the southern arm hooking away from the core to the southeast was more noticeable, while the apparent HII region just off the northern side of the core was also more apparent, though still quite tiny. Again, a beautiful galaxy, with similarities to M65 and noticeable differences as well.

NGC 3628 (Leo, barred spiral galaxy, mag=9.5, size=14.8’x3.0’, SBr=13.4):
North of the previous two objects and perpendicular to their major axis, I easily spotted this delightful ghostly object at 94x. It was large and bright, but in a dim sort of way. To clarify, it was quite obvious in the FOV, but it was more subdued than its neighbors to the south having lower surface brightness. Its disk was a thin edge-on orientation that seemed quite mottled to the eye. Going ahead to 152x it was quite a curious sight indeed, with glimpses of its central dark lane seeming to cross its disk at an odd angle to the major axis. This gave it a very uneven light distribution along the major axis. The northern half of the galaxy was much more prominent while the southern half was very weak, with only a modest amount of its envelope visible below the dark lane. This impression was significantly reinforced when viewing with 199x and even more so at 283x. The odd angle of the bisecting dark lane made split the light from the galaxy disk into very unequal halves with the northern portion along the major axis clearly dominant to what was seen below the dark lane. It was a most curious visual appearance, and added immensely to the allure of this triplet visually.

NGC 3132 (Vela, planetary nebula, mag=9.2, size=1.5’x1.4’, SBr=9.7):
With this one I was really digging down in the muck and mire of the horizon air mass at the Antlia-Vela border, as I dug it out at around 9° above the horizon. With the 13mm Ethos in the focuser (152x) I began back at mag 4.0 Beta Pyxidis and swept east and south until I located an asterism in northern Vela that I like to call the “Recognizer” from the old game Tron Deadly Discs, which I used to play as teenager. The shape of the grouping immediately reminded me of this character from the game the first time I saw it a few years ago. This group lies southeast of the planetary, so moving north from the western end of the “Recognizer” I located a small Bootes shaped group lying on its side, which pointed west to NGC 3132.

Putting eye to the eyepiece I slowly nudged west from the Bootes-like grouping and quickly swept up the bright planetary. It was more of an oval shape, large for a planetary and very bright. The mag 10.0 central star was readily apparent within its diffuse disk. Going to 199x I was seeing glimpses of an interior dark annulus surrounding the central star. The outer portions of the shell were quite diffuse and bright. Overall the disk was very uneven to the eye. I also applied the DGM NPB filter and the nebula responded well. The central star was tamed and the darker interior was more pronounced, while the overall impression was of an uneven and diffuse envelope. A much more impressive view, despite the very low elevation, than I had in a five inch from about 18° north latitude several years ago.

NGC 3115 (Sextans, lenticular galaxy, mag=8.9, size=7.2’x2.5’, SBr=11.9):
My last challenge object was this fine lenticular in the celestial sextant. Aiming the scope at mag 5.1 Gamma Sextantis I quickly located the field with the RACI finder west of a wide pair of stars (6th and 7th mag). I could just make out the presence of the galaxy in the finder as well as a tiny diffuse knot. Moving to the eyepiece, this time back to the Ethos 21mm (94x), the galaxy was a bright and large spindle of light. Its core shone brightly as a slightly elongated inner lens within the overall galaxy envelope. The ends tapered away from the slight central bulge of the disk, canted in a northeast-southwest orientation.

Dropping in the 13mm (152x) the galaxy was a true showpiece. Its disk was exceedingly bright sliver, its central bulge more pronounced and its ends extended further. I noted that its two ends did not extend evenly away from the core area. Rather the southwestern portion seemed to extend farther before fading into the sky than did the northeastern side, giving it a slightly uneven appearance. I have always found this a splendidly beautiful galaxy, and in the larger aperture it was indeed a true beauty.
Alan

Scopes: Astro Sky 17.5 f/4.5 Dob || Apertura AD12 f/5 Dob || Zhumell Z10 f/4.9 Dob ||
ES AR127 f/6.5 || ES ED80 f/6 || Apertura 6" f/5 Newtonian
Mounts: ES Twilight-II and Twilight-I
EPs: AT 82° 28mm UWA || TV Ethos 100° 21mm and 13mm || Vixen LVW 65° 22mm ||
ES 82° 18mm || Pentax XW 70° 10mm, 7mm and 5mm || barlows
Filters (2 inch): DGM NPB || Orion Ultra Block, O-III and Sky Glow || Baader HaB
Primary Field Atlases: Uranometria All-Sky Edition and Interstellarum Deep Sky Atlas
---------------------------------------------------------------------------
"Astronomers, we look into the past to see our future." (me)
"Seeing is in some respect an art, which must be learnt." (William Herschel)
"What we know is a drop, what we don't know is an ocean." (Sir Isaac Newton)
"No good deed goes unpunished." (various)
Some people without brains do an awful lot of talking, don't you think?” (Scarecrow, The Wonderful Wizard of Oz)
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