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19th March 2014 - More doubles for the list


philjay
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Extract from my log of last nights session:

A surprising clearish spell tonight 20:00hours, but a little windy with high thin cloud/mist and the prospect of lunar rising gave me at least a 2 hour window to have a play in.Due to the conditions I decided to go for some double/multiple stars.

Scope - Meade 127 ED Triplet Refractor.
Eyepieces used were Vixen LVW 22mm (43x), 13mm (73x), 5mm (180x), 3.5mm (272x)

I just had to have a look at Jupiter before starting on the doubles though and was greeted with the sight of Callisto right adjacent to the planets limb.  20:30 hours. As I watched the dark space between the two bodies widened.

On Jupiter despite the atmospherics the image wasn’t too bad at all with the major banding easily visible and the  pole darkening. 5mm was the max mag smaller than that lost detail. A good example for how the altitude of an object makes a difference to the views. Because Jupiter was so high the wind and atmospherics were less obviously messing the image.

 

OK so on to the doubles, Continuing with the SAC Catalogue of Double stars (Saguaro Astronomy Club), I picked on Cancer as I have not really done this constellation justice before.

All these doubles tonight were on the west of the constellation

 

STF1162
7.9 primary with easy 9.8 secondary at a 9.1â€separation. 20mm shows separation nicely, 13mm really opens it up, can I detect a slight redish tint to the secondary???? This double forms a nice triangle with 2 background stars fitting comfortably in the central fov.
        
STF1170,
Very close to 1162,. A nice test for conditions this one. Equal mag components at 8.5 with a separation of 2.4â€. The 5mm shows a slight space in between and this opens up nicely with the 5mm to a good clear gap. I like this double, two little eyes in space.
        
STF1173
Again in the same neighbourhood. Primary of 7.9 mag and apparently green but I could not discern any colour with a secondary of 9.6 mag at 10†of an orange colour. Now this I could discern every so often in still conditions. A nice double.

 

STT 186
Up on the Gemini border a 7.5 and 6.2 at a close 1†this pair. A good test of conditions. Hmmm, right on the cusp of seeing conditions, there is an easily discernible elongation at 5mm with an occasional split effect every so often. But its not easy tonight. I must revisit this one during better conditions

 

STF 1179      
Back down near the others, a nice wide pair to refresh my visual pallet this one. Another equal mag pair at 9.7 with a wide 22†separation. Easy in the 22mm no colour discernible.

 

STF 1181      
At the bottom left of the crab not too far from Beta CNC this 8 and 9.5 pair has a separation of 5.2. Easy split with the 13mm, is that blue in the secondary???? Too indistinct to be sure but catalogue has no colour association.

 

STF 1177      
Up near Gemini again, this 6.6 and 7.5 mag pair have a nice close 3.5†separation. These are nice and bright and look to be white and stand out well in a fairly clear background in the 13mm eyepiece. Nice.

 

STF 1196
Zeta CNC, (Tengmine) a multiple with 4 components.
The triple section is a difficult one and one which I have not been able to split before tonight but despite the wind I finally managed it. The components of the triple are mags 5.6, 6 and 6.2 with the 5.6 and 6 really close at 1", so close that only my 3.5mm would part them at times of steady seeing. The 3rd 6 mag component sits a comfortable 6†away. The 4th component is mag 9.7 a whopping 287†away. Great stuff being able to split this one. No colours apart from a slight yellow to the triple components.

 

STF 1186      
Blimey there's a few doubles near the Gemini border. This one at6.9 and 10.2 mags with a separation of 3.2 required some mag to separate using the 5mm and a lot of concentration a faint component flicks into view every so often at the 9 o clock position at my orientation. 

 

STF 1188      
Just above 1186 at 9 and 9.7 with a nice 16.1†separation this pair is easy compared to some of the others. The 22mm showing the pair nicely in a sparse background.

 

STF 1187      
Just above STF1188 is 1187 a nice bright 7.1 and 8 pair at a tight 2.9 separation.  13mm splits this easily

 

Conclusions, conditions were against fine separations with 1" the limit tonight. This scope on good seeing can resolve sub 1" easily at high mags but tonight 1" was the limit.

 

 

Having to pace myself these days health wise so a quick look at Jupiter, had a laugh at a very low Mars then packed up. At least I've looked at Mars now, couldn't see anything due to the conditions but I did it.

Edited by philjay
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Lovely. I've still not looked at mars through the scope since November when it was a morning object. I do find doubles are becoming more and more interesting as time goes by.

Sounds like you had a good night.

Jd

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