Observing Session 11/07/2006

[lunator]

Had a short observing session last night. (22.00 UT-23.30 UT)

Seeing 3-4/5 Started as a 3 and improved.

Transparency 3/5 - High cloud making the skies about Mag 4 at ZLM.

I had set the scope out to cool at 8.00pm (7.00 UT) and settled down to watch the Tour de France Highlights on on Eurosport.

When this was finished I set up my old laptop with Cartes du Ciel.

My main aim was to get a final set of timings for HJ258. I took 11 measures too give me 33 measures over 3 nights.

Night 1

Raw Timing 1 Timing 2 Timing 3 Timing 4 Timing 5 Timing 6 Timing 7 Timing 8 Timing 9 Timing 10 Timing 11 Mean

1.4 1.68 1.56 1.22 1.44 1.52 1.34 1.47 1.02 1.42 1.44 1.41

Separation 1.41 17.8"

Night 2

Raw Timing 1 Timing 2 Timing 3 Timing 4 Timing 5 Timing 6 Timing 7 Timing 8 Timing 9 Timing 10 Timing 11 Mean

1.09 1.41 1.1 1.1 1.44 1.28 1.09 1.4 1.25 1.15 1.44 1.25

Separation 1.25 15.8

Night 3

Raw Timing 1 Timing 2 Timing 3 Timing 4 Timing 5 Timing 6 Timing 7 Timing 8 Timing 9 Timing 10 Timing 11 Mean

1.34 1.12 1.38 1.44 1.28 1.31 1.41 1.35 1.29 1.41 1.44 1.34

Separation 1.34 16.94

Average PA 254 / Sep 16.85"

My next stop was HJ1277 more commonly known as Alpha Ser.

Thsi had not been measured since 1911 and the difference in Magnitude is imense. The primary is Mag 2. The secondary Mag 12. It is a wide pair of around 60". I could observe the pair fairly easily but totally accurate measurement was difficult due to the faintnest of the Secondary.

My observations gave a PA od 340/345 degrees and a separation of 65-75". These are only preliminary observations and will need to be refined. Looks like I'm going to have to buy a 12" scope....

I moved South West down to 5 Ser which is also known as STF1930. I had no plans to measure this pair but was interested to see if I could get the Globular M5 into the same FOV.

In my 18mm Ortho which has a true FOV of about 2/3 of a degree I was able to frame STF1930 and M5. The piar is about 11.5" part which at x67 is a fairly tight split.

M5 was a soft glow in the lower part of the view (North) and had couple of 11th Mag stars to the South that became more prominent with averted vision.

If you have a eyepiece scope combination that will give you 2/3-1 degree true FOV and about x70 Mag then I would recommend this as a target.

I finished the night with a split of Zeta Herc. Tight but split at x233.

Cheers

Ian

[Kain]

Wow that looked complicated!

I'm glad you have a productive night mate

Kain

[FLO]

Its great to have you aboard Ian

[lunator]

Thanks guys

The maths isn't that difficult.

I have the formula and a calculator.

The basic principle is just trigonometry. (all about right angle triangles)

I love doing this as I can make a contribution to professional astronomers with nothing more than a home made micrometer and a cross hair eyepiece.

Cheers

Ian

[daz]

A great report as always, and a productive one too!!

[The Warthog]

Always glad to see people doing interesting and productive astronomy, and having fun, too!

[OXO]

Excellent Report Ian, maybe you could share the formula with the members?

James

[lunator]

Excellent Report Ian, maybe you could share the formula with the members?

James

James

There are several versions depending on the process used. I'll write up a small taster and post.

I finally managed to glimpse the secondarry of HJ1269. It's listed as 11.6 but it's more like 12.5!!

Cheers

Ian