This is a little late getting posted, but the following is a recap of my session from last Friday night:
2023-02-10
Start Time: 19:15 local time (EST); 00:15 UT (02-11)
End Time: 21:45 local time (EST); 02:45 UT (02-11)
Length of Observing Session: 2h 30m
Cloud Cover: None
Wind: Light
SQM Measurement: 20.62
Temperature: -5C/23F
Relative Humidity: 77%
Transparency: Good (4/5)
Seeing: Good (4/5)
Instrument: Zhumell Z12 (fl1500, f4.9)
Mount: Dobsonian
Eyepieces: Explore Scientific and Meade PWA/UWA
Abstract: The main goal during this session was to observe the comet. Afterwards, to perhaps hit a few deep sky objects. The chosen instrument was the Zhumell Z12; this would be the first session since recollimating the scope again.
Comet C/2022 E3 (ZTF): A quick scan with binocular confirmed that the target was in the area anticipated. At 40mm (37x), the comet was easily located, not too far to the north-northeast of Mars. Even though the sky was not yet fully dark, the target appeared as a faint haze, resembling a nebula or galaxy at first glance. Careful viewing, however, showed that more of the nebulous haze appeared on the target’s northeast side than its southwest. A definite bright nucleus was visible, but not resolved. At 28mm (53x), the nucleus appeared more pronounced—almost stellar. Two or three background field stars could be seen shining through the wispy tail of the comet. The uneven distribution of the haze around the nucleus also appeared more pronounced. Averted vision showed a moderately well-defined, broad, fan-shape to the tail. This seemed to sweep along approximately 70 degrees along the circumference of the nucleus to the northeast. The sky continued to darken, making the broad sweep of the tail easier to see. At 20mm (75x), the target appeared reminiscent of an egg-shaped cocoon with a bright concentration near its internal southwestern edge. The resolution of the nucleus appeared slightly degraded for some reason. The curve of the “bow-shock” where the solar wind was pressing against the nucleus appeared to cover an angle of approximately 90 degrees. With averted vision, this appeared to widen to approximately 120 degrees. At 14mm (107x), the target appeared very bright. The hazy tail and bow-shock were brighter in the view. The nucleus regained its previous resolution. At moments, the solar wind shock appeared composite, with an outer and inner contour, but this impression (though repeated) was fleeting. The sweep of the tail and bow-shock appeared to stretch around approximately 150 degrees. Incredible. At 8.8mm (170x), the target began to soften in the view, but the bright nucleus remained very well resolved. The leading edge of the bow-shock was blurred and very difficult to delineate. The overall view was somewhat degraded. At this point, I reinstalled the 28mm ocular (53x) and conducted two quick and dirty sketches.
NGC 2420 (Gemini): Gemini appeared well-positioned in the sky, so I swung the scope into that region to hit a couple targets. At 28mm (53x), this open cluster was readily located. The target appeared to be composed of dimmer stars, with brighter field stars arranged around it—almost as if they were hemming it in or keeping watch to ensure that none escaped! The overall appearance of the cluster was that of a compact and dim arrangement. At 20mm (75x), the cluster members appeared more clearly defined. Perhaps 15-20 of the brightest members were easily resolved. Averted vision provided no improvement. At 14mm (107x), the cluster appeared mostly unchanged when viewed directly. Averted vision, however, revealed a fine sprinkling of dim points underneath. The cluster also showed an irregular overall shape. At 8.8mm (170x), the first signs of image darkening were noted. Averted vision still showed some of the underlying stars in the cluster, but the visible number was reduced.
NGC 2392 (Gemini): Beginning at 14mm (107x), I began scanning for this planetary nebula. This took some time, and I ultimately discovered why: I was holding the star chart in the wrong orientation! Ugh. After correcting this (and looking in the correct area!), it was finally located. At first glance, it appeared as nothing more than a bloated star with a uniform circular halo. Averted vision showed a homogeneous milky-white circle; it was easy to see the target was not stellar. At 8.8mm (170x), the direct view showed the “stellar” bright center, but this impression was lessened from that of the lesser magnification. The surrounding halo, however, appeared filled with swirls of nebulosity that outlined variations in brightness or concentration. Averted vision did not completely remove the “stellar” central spot, but it did allow glimpses of internal darker areas or gaps of lower concentration. The target’s overall shape remained circular. At 5.5mm (272x), the swirls in the nebulosity became visible directly, with some areas of lesser concentration apparent along the inner circumference. Averted vision revealed fine tendrils throughout the plantary—spectacular view! A slight central brightening was still noted. At this magnification, the target appeared slightly out-of-round. At 4mm (375x), I expected a view degraded beyond usefulness, but the target bore the magnification excellently. The tendrils noted earlier were now resolved into a complex texture, resembling white felt or fur—hence the planetary’s common name (the Eskimo Nebula). Despite this, no sign of a “face” was present in the view, as the slight central brightening noted earlier still remained, even though reduced. Beautiful view!
NGC 2331 (Gemini): At 40mm (37x), numerous attempts were made to obtain a positive identification on this cluster. (And, yes, I made certain I was holding the atlas in the correct orientation!) The cluster is very loose and easily blends in with the field, so it is no surprise that I was unable to positively acquire it.
M42 (Orion): At this point, the cold was numbing my feet (despite multiple layers of clothing). But, I could not end the session without a quick look at the Orion Nebula. At 40mm (37x), the target was nothing short of glorious! The nebulosity was amazing, with bright streaks and puffy concentrations within. The Trapezium stars were already resolved. NGC 1973 and NGC 1980 fit into the same field.
NGC 1973 (Orion): At 40mm (37x), the dim nebulosity of this cluster north of M42 was visible. The dark dust lanes within could be seen outlining the Running Man. This was only *just barely* visible, but definitely there. Awesome view!
NGC 1980 (Orion): South of M42, this cluster also showed some minor visible nebulosity. Very nice.
Conclusion: At this point, my feet were literally throbbing with the cold, so the session had to end. I regretted not being able to stay out longer, but the session was an unmitigated success. Also, the recollimation of the Z12 appeared to pay off, as this session provided the best views obtained with it so far.
Until next time!