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Object of the Week May 28, 2023 - NGC5669 in Boötes
Let's talk about Boötes first: it's a bit of a troubled constellation. And not just because it is the only one with a diaeresis in its name.
In springtime at mid-northern latitudes, the constellation does not approach the meridian until the early morning hours. Requiring either a long observing session while battling fatigue, or an alarm set to leave the bed at a time when our circadian rhythm is approaching its natural low. Closer to summer, it transits around midnight. The time of year that requires us stargazers to sit out the evening until the skies are finally darkening, inconveniently coinciding with the prime hours for beer & BBQ. By the time darkness is upon us at more reasonable times, the constellation is already well past the meridian and much lower in the western sky.
Yet, for those of us who have the patience to focus on a summer session starting close to 0:00 hours, the Herdsman has a lot to offer. Galaxies aplenty. Still, the constellation's reputation - to many - is it being "Quite empty. A not-too-bright-globular and less than a handful of moderately bright galaxies, that's it", as I have often heard.
Yes, it may not pack a plethora a bright fuzzies as the preceding neighbors do, but any 8"+ scope will be able to bag a lot more than, for instance, only NGC5248, 5557 & 5676.
One of the nicer galaxies in Boötes is NGC5669, this week's Object of the Week. It lives close to the constellation's southern border @ 14:32:44 +09d53m30s. That's exactly 10 degrees south-southwest of Arcturus.
Discovered in the year 1784 by William Herschel, who catalogued it using his designation / classification of II-79 (II for "faint nebula"), it made it into Dreyer's catalog with the summary description of "F, L, R, lbm, r": Faint, Large, Round, little brighter middle, resolvable (mottled, not resolved).
The description "mottled" is fitting to this galaxy. As images show, it contains a lot of little specks that ought to reveal themselves in larger apertures.
From left to right: 15' POSS2 Blue, Red, SDSS & PanSTARRS.
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What will stand out in smaller scopes, is the elongated core, orientated NE to SW.
The overall shape of the galaxy is more oval than roundish, but the brightest parts may give it the appearance of being slightly elongated north to south whenever the fainter outer regions remain out of sight due to lack of aperture, transparency, or both.
My log contains a single observation for NGC5669, 10 years ago in the French Alps using my 12" SCT. Back then, in that aperture, the galaxy did indeed reveal irregular structure. No nucleus was observed. However, SSW of the elongated core, I did note a faint, stellar 'dot' resembling a mag. 15 star, as I described it. As can be determined in the images, that's one of the brighter HII regions in the galaxy's southern arm.
As always, there is an observing guide for the OotW. Click here to download.
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Enjoy and be sure to report back!
