M44's doubles

[Talitha]

A few years ago I had a blast investigating the doubles in M44 and thought you might have some fun with it, too. Here's my write-up and two charts to use as road maps.

Heaven only knows if I'll get to see M44 again this year with all these clouds, but I'd like to make some sketches. It was too cold last time.

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M44's doubles, 5 February 2006

Location: 45°28'N // 89°43'W (Tomahawk Wisconsin, USA)

Date/Time: 6 February 2006, 02:00 UT

Scope: f/8.3 Sky Watcher 120 achro

Eyepieces: 32mm Meade super plossl (31x); 13.8mm Meade SWA (72x)

Conditions: 12°F (-11°C) with a 10mph wind

Seeing: 5/10

Transparency: 5/10 (60% illuminated 8 day Moon, at an altitude of 60°)

(Position Angles, Magnitudes and Separations obtained in 2006 from the Sky Tools program)

S 570 (HD 73449)

A/B __ 7.45 / 9.5 __ PA 84° __ Sep 57.50"

A/C __ 7.45 / 9.5 __ PA 345° __ Sep 178.00"

A= white

B= bluish-grey

C= light bluish-grey

13.8mm Meade SWA (72x)

I could tell visually that B&C were very close in magnitude and as it turned out, they were the same. C appeared to be a bit brighter than B, but I'm guessing it might have been an illusion caused by it's distance from A.

Struve 1249

A/B __ 9.5 // 9.5 __ PA 40° __ Sep 25.00"

A= bluish-grey

B= bluish-grey

13.8mm Meade SWA (72x)

This exquisitely delicate pair is located about a minute and a half NE of a magnitude 7.7 star (HD 73174). The star's brightness and the moonwash made it necessary to use averted vision for the best view, but it was still do-able.

S 571 (HD 73618)

A/C __ 7.29 // 7.2 __ PA 156° __ Sep 45.20"

A/D __ 7.29 // 6.7 __ PA 241° __ Sep 92.90"

A= white

C= bluish-white

D= yellowish

13.8mm Meade SWA (72x)

There are two more stars to the system (B&E), but I skipped over them because they were too dim or too close for me. (For the curious though, the A/B pair is 7.29 // 11.9 with a separation of 1.40", and the A/E pair is 7.29 // 9.87 with a separation of 0.49".)

A was visually dimmer than D, and I thought it odd that D was brighter.. isn't the A star usually the brightest? Oh well, it's a very pretty grouping anyway.

S 574 (Epsilon Cancri)

A/B __ 6.29 // 7.4 __ PA 249° __ Sep 134.90"

A= yellowish (looked like D in S 571)

B= white

13.8mm Meade SWA (72x)

Struve 1254

A/B __ 6.42 // 9.0 __ PA 54° __ Sep 20.50"

A/C __ 6.42 // 8.7 __ PA 342° __ Sep 63.20"

A/D __ 6.42 // 9.0 __ PA 43° __ 82.60"

A= yellowish

B= grey-blue

C= grey-white

D= grey-blue

13.8mm Meade SWA (72x)

B and D are the same magnitude, but B appeared much dimmer due to its closeness to A. However, B and D looked much the same with averted vision when A was placed outside the FOV.

39 Cancri

A/B __ 6.39 // 6.5 __ PA 151° __ Sep 149.80"

A/P __ 6.39 // 8.9 __ PA 309° __ Sep 134.10"

A/Q __ 6.39 // 9.2 __ PA 110° __ Sep 135.00"

B/R __ 6.5 // 10.4 __ PA 147° __ Sep 140.00"

A= white

B= white

P= grey

Q= grey

R= grey

13.8mm Meade SWA(72x)

This was by far the most spread-out system in the open cluster, and the dimmer components were pretty easy to see despite the moonwash.

[jgs001]

Thanks for the info Carol, looks interesting.

[lunator]

Carol

Very nice report

Doubles in clusters are one area of DS observing I haven't pursued as far as I might. When I look at doubles I get side tracked into looking at all the pretty patterns etc.

I hope you get a clear sky soon.

Cheers

Ian

[Talitha]

Thanks John and Ian! Just got finished setting up the windbreak for some lunar work with the SCT tonight and will try to get the sketches of M44's doubles done, too. The Moon's really close to the cluster, though... I'll see how things look.

[lunator]

I hope the session goes well.

It's raining here in London....

Cheers

Ian

[Talitha]

Well, it went pretty good considering the Moon was only 4° away. There was absolutely no hope of finding M44 with the red-dot, so I calibrated the LX-10's setting circles on Regulus and dialed my way in.

As expected, the moonwash bleached out the star colors, but unexpectedly, I squeezed out a mag 12 star in S 570 (GSC 01395-2098). It was difficult at best and required some OTA tapping, but the dim point of light consistently popped into my averted sweet spot when I looked down towards 4:00 from the target. Never thought it would have been possible with the Moon so close.. live and learn, I guess.

Anyway, here are the sketches. The groups overlap in a few, but I chose to include them as background stars in order to give an accurate rendering of what was in the fov while each group was centered.

[jgs001]

Excellent Carol. Must have been tough with the moon that close, but the are superb. :hello1:

[lunator]

Carol

Excellent drawing. Much neater than my double star sketches.

I recognised the field around S 571 immediately

Cheers

Ian

[Talitha]

Thanks!