November 2021 TSS Monthly DSO Challenge

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November 2021 TSS Monthly DSO Challenge

#1

Post by kt4hx »


We were over at the dark site for a couple of nights and I revisited the northern objects for this month using the 17.5 inch scope. Here are my notes, which are part of a larger report for the first night, which I link here: viewtopic.php?f=6&t=21696

NGC 869 (Perseus, open cluster, mag=5.3, size=30.0’, class=I3r):
NGC 884 (Perseus, open cluster, mag=6.1, size=30.0’, class=I3r):

Facing the northeast, I could easily see the infamous Double Cluster with the naked eye. While my 17.5 inch isn’t the best instrument to use for these showpieces, I dropped in the 21mm Ethos (94x) and quickly aimed the scope their way using the Rigel unity finder. What greeted my eye in the 1.1° TFOV was an explosion of stars. Too much so actually, as my true field could not contain all these clusters have to offer. That is why they are much better fare for binoculars and smaller wide field instruments, in the same manner as M44 and M45. Wider, lower magnification views give one a much better perspective in these larger cluster fields within the surrounding sky. Nonetheless, my eye was dazzled by myriad stars curving and streaming in all directions, with countless little patterns formed among their number.

Messier 33 / NGC 598 (Triangulum, spiral galaxy, mag=5.7, size=66.0’x41.41.6’, SBr=14.1):
Aiming my scope using the Rigel unity finder to the galaxy’s approximate location, I quickly scooped it up in the 8x50 RACI optical finder. Again at 94x, as my eye relaxed and adjusted to the field in which it swims, the galaxy began to take shape. After a few moments its delicate and diaphanous spiral structure became readily apparent, with the soft low surface brightness arcs of its light unwrapping from a noticeable broadly brighter core. The arms were curdled with countless pockets of light and dark structure as the eye moved outward. The large and bright H-II region NGC 604 was an obvious punctuation to one of the arms as it trailed off to the northeastern edge of the galaxy. Though conditions were not superb, they were more than good enough to let this true beauty of the Local Group strut its stuff for my pleasure.

NGC 7789 (Cassiopeia, open cluster, mag=6.7, size=25.0’, class=I2r):
Aiming the scope now at mag 2.3 Beta Cassiopeiae (Caph) I drifted nearly 3° SSW of the star and quickly scooped up this fine open cluster in the 8x50 RACI optical finder between Rho (mag 5.1) and Sigma (mag 4.9) Cas. In the finder it presented a small and round diffuse glow with no stars resolved. However, it was clearly evident and invited closer inspection. Moving to the eyepiece (94x), the sight was a stunning round mass of stars, far too many to count with any reasonable accuracy. In fact, the amount of stars visible was dizzying and confusing – but beautiful all in the same moment. As I studied the cluster’s field more, I began to get a sense of darker voids of less stellar density within its structure. I could trace flowing curves of these voids as they wound their way throughout the cluster body. This lent a very curious maze-like appearance to this wonderful cluster. While I have seen it previously with smaller apertures, the view in this scope was simply overwhelming.
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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kt4hx United States of America
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Re: November 2021 TSS Monthly DSO Challenge

#2

Post by kt4hx »


I also had the following observation of M33 in September of last year at the dark site with the 17.5 inch in which I specifically targeted some of its brighter H-II regions:

Messier 33 / NGC 598 (Triangulum, spiral, mag=5.7, size=1.1°x41.6’, SBr=14.1):

Observed at 110x and 152x it presented a large oval that filled the field of view (0.7°) in both eyepieces (ES 82 18mm and Ethos 13mm). It was seen as a very obvious and bright oval that revealed diaphanous spiral structure. Its appearance was heavily mottled and uneven across its dimension. The core was bright and quite diffuse in appearance, being slightly elongated in the major axis.

Numerous HII regions were noted, ranging from bright to very dim. These are the ones I could identify based on a chart that I had printed out. I then studied the galaxy’s structure for a while and picked out a few of its HII and star cloud regions.

NGC 604 - Observed previously, this emission nebula presented a bright and very obvious small knot of concentrated light near the end of a spiral arm. It was in your face obvious in the eyepiece.
IC 143 - Just WSW of NGC 604 I picked up this dim, but not a difficult small knot. (New)
IC 142 - Following the chart I spotted this very small and weak concentration southwest of IC 143. (New)
NGC 595 - About 6’ southwest of IC 142 I found this small knot fairly obvious. (New)
NGC 592 - About 5.5’ further to the southwest from NGC 595 I easily picked up this small knot of brightness within one of the interior arms. (New)
NGC 588 - Nearly 6’ west of NGC 592 I picked up this small knot of brightness in the next arm out from that containing the previous object. (New)
IC 139 and IC 140 -This pair of HII knots lie south of the bright diffuse core in an inner portion of their resident arm. Aligned north-south they were both fairly subtle to the eye but definitely seen. (New-2)
IC 136 - Just east of the previous pair, I noticed this larger mostly circular patch about 1.5’ in diameter. It was not visually strong, but still easily seen. (New)
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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