Some doubles and triples in Aquila

..... whenever we get some clear skies, John.

I wonder when are we going to have some clear skies.
There is so much high and medium hazy cloud over us constantly.
But that's a typical August.

By the way, I hope your focuser is equally as good as mine!
A 4" refractor is lovely and light to handle.

Kind regards from Aubrey.

Hello, everyone, once again.

On Monday 26th August I was out again with my William Optics 158 mm f/7 apochromatic refractor under Bortle 9 skies in my back garden.
There was no wind or turbulence throughout the whole night for 3.5 solid hours.

I had printed off a good map from my Guide 9.1 DVD.

The first 6 doubles are all north of the open star cluster NGC 6709 in Aquila.

It is my first time I have ever observed any of them.

1. Stta 174. A= 7.5. B= 8.3. The separation is very wide at 104.6". PA is 158 degrees. Easily split at 40X of course.
It is an optical double.

2. Stf 2396. A= 8.1. B= 11.3. Separation: 82". PA= 337 degrees. Because that secondary is extremely faint, I required 112X to see it. Optical double.

3. Stt 362. A= 8.3. B= 11.9. Sep: 7.8". Quite tough to see both stars. 167X was sufficient to see A and B with a decent amount of black space between them. Astronomers tell us they are uncertain if it is a true binary. But that's okay.

4. Stf 2402. We all love tight doubles. Here is one for you all. A= 8.9. B= 9.3. Sep: 1.4". PA= 208 degrees. It was not fully split at 112X. But at 140X and 167X, my scope split it alright. Gorgeous sight! -even though it is uncertain if it's a true binary. Never mind -what a grand but faint double. It is northwest of NGC 6709.

5. Stf 2408. A= 8.5. B= 9.4. Sep= 2.3". PA= 91 degrees. Super tight split at 112X. Uncertain double -but it definitely is worth seeking out.

6. BU 265. A= 7.4. B= 9.2. Sep= 1.4". PA= 231 degrees. So you want a real challenge. A full 1.8 magnitude difference in delta mag plus it is so tight. 167X was not enough. But I am very happy to say my 225X 5 mm Nagler saved the day (or night). A is white. B is yellow. What an achievement to an uncertain double!

7. 23 Aquilae. A=5.3. B= 8.3. Sep= 3.2". PA= 2 degrees. I read about this tough true double over on the sketches forum on Cloudy Nights. It has been about 10 years since I observed 23 Aql. My apochromatic refractor nearly had it split at 112X, and that is considering there is a full 3 magnitude difference. Sitting on top of the yellow primary was the faint secondary. At 140X I got the desired split. But I did increase up to 167X and 225X. It brought great pleasure to the eye.

8. Can I see all 3 components of 5 Aquilae? And at what power? The magnitudes are: A= 5.9. B= 7.0. C= 11.3. The separations are 12.6" and 21.8" with PA's of 122 and 156 degrees. Thankfully because of those decent separations I could see A and B split at 40X very easily. The C star was no problem either -seen at 112X and 140X. I increased my magnifications up to 167X and 225X to further prove to myself that all 3 stars were visible at all times.

It was one of my best observation nights of 2019.

Comments are very welcome.

Clear skies,

Aubrey.

Very impressive that you can split those tight and faint doubles in Bortle 9 skies Aubrey. Just shows what can be achieved with a good scope in unfavourable conditions, and that light pollution need not necessarily be a barrier to productive observing.

Finbarr.

Thank you for your kind comments, Finbarr.
All we need is a bit of patience and to stick with the desire to split even the tightest doubles.
Sometimes we will need that extra magnification to see the very faint.

What fun is to be had. NGC 6709 is a wondrous open cluster. It led be to many hidden binaries.
That double Stf 2404 has great charm. Easily wins me over.

Kind regards to all,

Aubrey.