While July is mostly warm and makes for some balmy nights in which to observe, the big downside is that it doesn’t get dark until around 11:30pm. We’ve had a huge high pressure area over us for the last 10 days, but despite a lot of clear nights, I’ve been too pooped to stay up till that late hour and do a couple of hours at the scope. However, last Thursday, I was sufficiently spritely to give it a go.
It still wasn’t completely dark at the start of the session, but by half way through, the Full Milky Way could be seen – stretching from Horizon to Horizon. Seeing was stable, but the transparency while cloudless, was quite hazy, so the record got a ‘Mostly Clear’ rating. I guess that 98% Humidity explains that, but looking at the airmass figures for this session, I see that observations were made through air masses ranging from 6.1 for M62 to 1.7 for M12 and M14. However the other observations were averaging 3 to 4 air masses, so coupled with the humid conditions explains the lack of clarity on some of my observations.
Still trying to bag the last few objects in Sagittarius while I have the chance, but a row of trees were perfectly placed over M24, M69, M70 and M55 to deny me that, so I continued the current bout of Globular observations, by moving into Ophiuchus.
- Date: 11/07/2013
- Time: 22:37 – 00:16 UT
- Temp: 11.0c,
- Air Pressure: 1018Mb,
- Humidity: 98%,
- Dew point: 10.8c,
- Wind Speed: 4.0 MPH .
- Seeing: I Perfectly Stable,
- Transparency: Mostly Clear.
West is to 10 o’clock. In Altair Astro 250mm, Delos 14mm, 145 X, 29.8′, Globular appears circular…averted vision makes no difference. Very low on the horizon and is too low to make a meaningful observation pointless. Just looked at the airmass for this observation – 6.1..Eak!
Through the Altair Astro 250mm, Delos 14mm, 145 X, 29.8′, is huge. Four stars form a rectangle lying on its side. Takes up a 1/4 to a 1/3 of the eyepiece. West is to the 10 o’clock. Globular is offset to the right of the rectangle.
Core is unresolvable and dense, except a few brighter stars scattered around. On closer examination a number of stars form a line running up/down. Another similar line of 4 stars form a ‘V’ with the first line, forming a point to the 7 o’clock and the open end of the ‘V’ to the 2 o’clock.
With the Altair Astro 250mm, Delos 10mm., 203 X, 21.3′, the ‘V’ is a little more detailed but the contrast drops off.
Altair Astro 250mm, UWA 18mm, 113 X, 43.6′, If you come at the eyepiece quickly, the Globular takes on a slight oval squashed from the top.
Background is nice and dark
West is to the 10 o’clock . It’s quite big and takes up about 20% of the FOV in Altair Astro 250mm, UWA 18mm, 113 X, 43.6′, As soon as you come the eyepiece the globular looks oval and oriented 1 to 7 o’clock. What’s really wierd is that as you examine it, that shape disappears. Unlike M12, the stars that make up this object are much finer. There are no brighter stars resolvable in the core, which looks almost nebulous. It sits on a nice dark sky.
n Altair Astro 250mm, Delos 14mm, 145 X, 29.8′. Doesn’t add much to the view. Except now you can start to make out a few brighter stars scattered randomly within the core area. The core now takes on that oval shape seen in the Altair Astro 250mm, UWA 18mm, 113 X, 43.6′, except now the direction is 10 to 4 o’clock – really wierd.
Altair Astro 250mm, Delos 10mm., 203 X, 21.3′, gives the same view, you just lose contrast.
TMB 80 f/6, Plossl 26mm, 18 X, 2.7°, Very small and if you were scanning the FOV quickly, you would miss it.
Wayhay. Getting nice and dark and i can now clearly see the Milky Way from Horizon to Horizon.
Altair Astro 250mm, UWA 18mm, 113 X, 43.6′ Very faint and diffuse. West is to the 11 o’clock . Only one resolvable star in the cluster core.
Altair Astro 250mm, Delos 14mm, 145 X, 29.8′ Much the same with a few more resolvable brighter stars. Core still very soft. Quite small, taking up about 10%- 15% of the FOV.
Altair Astro 250mm, Delos 10mm., 203 X, 21.3′ More resolvable brighter stars start to appear.
In TMB 80 f/6, Plossl 26mm, 18 X, 2.7° hardly seen and only in Adverted vision.
Altair Astro 250mm, Delos 14mm, 145 X, 29.8′. very faint, but conditions look as though they are deteriorating, although Milky Way is still visible. Core very diffuse with a few solitary brighter stars. Size about 10% of the FOV. Background still quite dark and you do get a sense of it being an island on a black sea.
Altair Astro 250mm, Delos 10mm., 203 X, 21.3′ . the view goes tits up with contrast dropping through the floor and becoming difficult to focus on.
Altair Astro 250mm, UWA 18mm, 113 X, 43.6′ Very small fuzzy blob…Yuk
Very faint and diffuse. It almost looks like nebulosity, rather than stellar. West is to the 9 o’clock
Globular seems to be embedded in a crucifix of stars oriented 2 to 7 o’clock. Of all the star asterisms seen this evening, these are the only only ones that are identifiable on the star chart.
West is to the 9 o’clock . Defuse and very small, although it is possible to resolve a few stars within the core area. Size about 10% of the FOV of Altair Astro 250mm, Delos 14mm, 145 X, 29.8′,
It’s at this point, the voice recorder packed up, so ended session. Reading through James O’Meara’s ” The Messier Objects’ I was pleased to see I’m recording a number of features that he also mentions – a sign that at least the more obvious characteristics are being seen the same way. Where this didn’t happen, was his recording of various colour shades in these globulars. Either conditions are poorer, or I’m so busy recording shapes, orientation and size, that I’m missing this aspect.
Another enjoyable session.