May 2021 TSS DSO Challenge

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May 2021 TSS DSO Challenge


Post by kt4hx »

Okay, here is a partial submission from me of my visual experiences with the May objects. The below notes are from an observing session at our dark site house with the 17.5 inch dobsonian the evening of 01 May. These are the five northern objects for May, plus the northernmost southern object, M68. I have observed all these previously with various instruments from various locations, but this is the first time I have targeted them from our dark site with the large scope. Some are easy and some are more challenging, but all are fun and tools by which we learn to become better observers. The below is all part of a larger report that is still a work in progress and will be posted in the Reports forum at some point. I hope you enjoy reading along, and I encourage all to post your results whether visual descriptions, sketches or images in the Submissions sub-forum of the TSS Monthly DSO Challenge forum. Good luck friends. :)

Messier 3 / NGC (Canes Venatici, globular cluster, mag=6.3, size=18.0’, SBr=12.3, class=6):
Already knowing the cluster is located almost halfway between Arcturus (Alpha Bootis) and Cor Caroli (Alpha Canum Venaticorum) I aimed the scope using the Rigel Quikfinder. Moving to the RACI the cluster was easily visible as a tiny diffuse spot not too far off the cross-hairs in the view. Centering it, I moved to the Ethos 21mm (94x) and my eyes were treated to a beautiful sight. Bright and large, the cluster appeared slightly out of round to the eye. A large number of stars were resolved in its halo, as well as across the face of the disk. The core was a bright hazy glow providing a backdrop for the stars that were resolved.

Dropping in the Ethos 13mm (152x) it was a grand visual treat. Not quite symmetrically round in shape, it was a huge glowing ball of stars, with countless resolved at its fringes into the core area. The core itself was an intensely bright glow that underpinned the whole visual experience. I noticed several strings of stars emanating from the cluster’s body. In particular I noticed one curving flow coming off the northern side and turning to the northeast. Another that I took note of was one that was thicker closer to the core and thinned out as it strung out to the east. This cluster is a perennial favorite, and it is easy to see why. Give it a try yourself and enjoy the view!

NGC 5466 (Bootes, globular cluster, mag=9.0, size=9.2, SBr=13.7, class=12):
A short 5° star hop to the east of M3 is this more challenging globular. Easily passed over if you are not looking for it, its lack of any significant core concentration means its light is spread out evenly across the disk, reducing its visibility. I easily spotted it at 94x as a large ghostly orb lacking any concentration of brightness across its face. As the weak seeing was changing, various member stars would pop in and out of view across the disk, with a persistent hazy backdrop of the unresolved constituency. Viewed at 152x it presented a large and subtly bright ball that seemed a little ragged around the edges. Countless stars were again popping in and out of view across the disk with the constant backdrop of a hazy glow. I did notice a strand of dim stars flowing from the northeast side and wrapping around to the south. While not a showpiece, its eerie appearance is nonetheless attractive and curious.

Messier 53 / NGC (Coma Berenices, globular cluster, mag=7.7, size=13.0, SBr-13.0, class=5):
Next up was this nice cluster about 57’ northeast of Alpha Comae (Diadem). The cluster was just picked up in the RACI finder and of course quickly found using 94x. It presented a large and bright round glow with a very intense core blazing at its center. The core was tight, but numerous stars were resolved in its outer halo and across the face. Viewed with 152x it was a real showpiece. Large and bright within the field, its core was exceedingly strong, with its well resolved halo extending outward. I noticed about three or four short chains of stars trickling outward from the core into the halo. While not the rival of M3, it still holds up well visually and is well placed near a bright star.

NGC 5053 (Coma Berenices, globular cluster, mag=9.0, size=10.0’, SBr=13.7, class=11):
As NGC 5466 was the antithesis to M3, so too is this globular to M53. Nearly 58’ southeast of M53, it is another one that must be specifically targeted or it could easily be overlooked. As a class 11 cluster, it lacks any significant core concentration, which lowers its surface brightness. Thus it suffers greatly from the impact of light pollution, struggling to push through the sky glow. But from our dark site, it was easily seen at 94x, though admittedly it was merely a smallish diffuse dusting against the black sky. Perhaps 10 stars were resolved across its disk. Moving up to 152x, it remained a low surface brightness round glow. I picked up about 20 stars that drifted in and out of view across its disk, but its dominant characteristic was its low surface brightness hazy glow. This one presents a ghostly ethereal personality in the eyepiece, diaphanous and delicate.

NGC 4147 (Coma Berenices, globular cluster, mag=10.4, size=4.4’, SBr-13.4, class=6):
The final of three globulars in this constellation is a small little thing. Found almost 6.5° northwest of Denebola (Beta Leonis), using 94x it displayed a tiny concentrated brightness in the core, with perhaps four or five stars resolved in its outer fringes. When viewing with 152x and even 199x, it was bright but quite small visually. Upwards of 10 stars were being seen in its outer halo and across its face. Interestingly, my last observation was from our typical suburban backyard about eight years ago with my 10 inch. In that case, it did not appear clearly as a globular cluster, but brought to mind a small elliptical galaxy as no stars were resolved. This one is challenging because of the combination of its visual magnitude, small angular size and moderately weak surface brightness.

Messier 68 / NGC (Hydra, globular cluster, mag=7.3, size=11.0’, SBr=12.2, class=10):
After finishing with the first portion of my galaxy hunting, the sky had shifted enough for me to pursue one of the southern globular clusters in this month’s TSS Monthly DSO Challenge. About 3.5° southeast of Beta Corvi (Kraz), it was easily found lying next to a triangle of three field stars (two of 8th and one of 9th mag). With 94x it presented a bright and slightly small irregularly round glow. A few stars drifted in and out across its disk, which displayed a modest central brightness. Viewed with 152x perhaps a dozen stars were now seen overlaying a slightly dense core brightness and general haziness of the cluster’s unresolved members.

Astro Sky 17.5 f/4.5 Dob || Apertura AD12 f/5 Dob || Zhumell Z10 f/4.9 Dob
ES AR127 f/6.5 & ED80 f/6 on Twilight-II || Apertura 6" f/5 Newtonian on Twilight-I
TV Ethos 100° 21mm, 13mm || ES 82° 24mm, 18mm || Vixen LVW 65° 22mm
Pentax XW 70° 10mm, 7mm, 5mm || barlows
DGM NPB Filter || Orion Ultra Block, O-III and Sky Glow Filters || Baader HaB Filter
Primary Field Atlases: Interstellarum and Uranometria All-Sky Edition
"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)
"The eternal silence of these infinite spaces frightens me...." (Blaise Pascal)
"No good deed goes unpunished." (various)
"I have become comfortably numb." (Roger Waters)
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