July 2021 TSS DSO Challenge
Posted: Sat Jul 31, 2021 1:56 am
I have had the good fortune to observe all this month's challenge objects. Since all of the northern and half of the southern objects are from the Messier list and have been observed countless times over the decades with various apertures and under widely varying conditions, I will abstain from posting my observations for them. However, since I've only seen the most southern objects in this month's list three times during my business trips closer to the equator, I will focus my submission on them. The following observation was from five years ago from 5° south latitude under skies that were Bortle 5 at best. I was using my ED80 refractor at the time.
NGC 6188 (Ara, bright nebula, mag=unk, size=20.0’x12.0’):
During the session two nights ago, this object was difficult and elusive. Given how bad seeing had been this evening, I was hoping transparency had picked up just a little bit and that maybe this nebula complex would be a little easier to pin down. So I slowly moved south a little more than 1° fromNGC 6200 until I located the bright cluster NGC 6193. Staying at 27x for the 3.2° TFOV, I moved my eye around in all directions from the cluster. As with the previous session I was getting a sense of very subtle haziness. I inserted the Ultra Block filter and the haziness picked up just a little more. I noted some haze particularly around the brighter stars in NGC 6193, and got a sense of a little more density to the north and to the west of the cluster. I then put in the O-III filter. This time the O-III did make a noticeable difference. Though its presence still remained subtle, it was more discernible in the O-III particularly to the north and west of the cluster. The view just gave an overall impression of looking through a thin haze of dusty air. You can see, but things seem ever so slightly unclear. So it would seem my guess about the transparency was correct, and it was most definitely was more visible this time. Though granted, in the 80mm it was still a diaphanous presence.
NGC 6193 (Ara, open cluster, mag=5.2, size=15.0’, class= II3p):
At the southern end of theNGC 6188 complex, this cluster is responsible for both illuminating the reflective portions and energizing the emission portions of the nebula. At its heart is a dazzling pair of stars at magnitude 5.6 and 6.9. Using the 18mm for 27x, I saw about seven or eight stars, with the brightest of them showing some haziness around them (the nebula). At 43x, about 10 stars were seen with most being east and southeast of the dominant pair. At 71x and 102x, I counted upwards of 15 stars scattered to the eastern side of the central pair. These peripheral stars formed a “C” pattern, like Pacman trying to swallow up the bright pair. The whole time the central pair remained enveloped in a dim haze of nebulosity.
During the session two nights ago, this object was difficult and elusive. Given how bad seeing had been this evening, I was hoping transparency had picked up just a little bit and that maybe this nebula complex would be a little easier to pin down. So I slowly moved south a little more than 1° from
At the southern end of the
