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Old 05-01-2009, 01:36 PM
Coen
"Doc"

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Location: Adelaide, Australia
Posts: 180
70mm Refractor - Col Tour

Hello All,

Continuing on some of the smaller constellations I decided to have a look at the dove - Columba. I compiled a list of objects to look at and got started. Given various circumstances the viewing was spread over a number of nights and I have a few more double stars to check out yet.

24 December 2008 to ?? local time +10.5 to UT

Telescope is 70mm Skywatcher Refractor with the 25mm Plossl, 25mm basic, 15mm GSO, 10mm basic and 6mm Plossl.

In the documentation if unspecified the eyepiece is 60x 15mm GSO.

Tour of Columba - the dove

Due to daylight savings and changing weather objects viewed over a number of sessions with variable seeing/transparency.

Maps are Taki's double star atlas maps 27/28

Tri-Atlas Hybrid (M) 159-161, 184-186
Tri-Atlas (B) 78,79,95,96

Observing list compiled from CNebulaX, Taki's double star list and consultation with the WDS database.

24 December, times not recorded, took opportunity of small window of time. Notes written a number of days after viewing.

NGC 1891
Non-descript small group of stars, more of an asterium than anything else.

NGC 2061
As with NGC 1891, small group of stars, more compact than NGC 1891.

HJ 3760
Nice triple star that is worth looking at again. The fainter third component is readily seen and reasonably straight forward.
Documented: Magnitudes 7.7 & 10.6 at 29.1", 7.8 & 8.4 at 7.4"

NGC 1851
Globular cluster that has a bright glowing circular core, no resolution but pretty none the less.
Documented: Magnitude 7.3, 11'

NGC 1792
Sausage shaped faint glow, nice stars nearby.
Documented: Magnitude 10.2, 5.6'x2.9', SBbc, Surface Brightness 12.9

NGC 1808
Near NGC 1792, appears to be more circular than NGC 1792 but is seemingly harder to see although its magnitude is brighter. Might be something coming off the edges but unclear.
Documented: Magnitude 9.9, 6.5'x3.9', SBa, Surface Brightness 13.3

NGC 2090
Galaxy near alpha Col, not seen.
Documented: Magnitude 11.2, 5'x2.5', Sc, Surface Brightness 13.7

27 December

HJ 3858 (2230)
Triple star arrangement, main is orange and bright, secondary is a close pair that is widely separated from the bright main. The fainter pair are perhaps pale yellow and light green.
Documented: Magnitudes 6.4 & 7.6 at 132" and 7.6 & 8.2 at 3.8"

HJ 3830 (2250)
Nice almost equal pair both pale orange close together, PA close to 0deg
Documented: Magnitudes 8.1 & 8.4 at 6.2"

HJ 3825 (2300)
Wide and very unequal, main is very bright and has second bright star nearby. Secondary is faint, see with averted at 60x and somewhat in line with the other bright star, see with 90x averted also.
Documented: Magnitudes 7.2 & 10.4 at 33"

HJ 3823 (2330)
Two equal stars that are very close together - hard to split with the poor seeing conditions, maybe at 60x, clearer but tough at 90x has another star nearby and somewhat analogous to HJ 3825.
Documented: Magnitudes 8.9 & 8.9 at 2.4"

30 December

Dun 28 (2155)
Two components easily visible, faint star from secondary, perpendicular to main pair (magnitude 11.3), averted clear at 60x, 90x no averted needed. 3rd component might be visible with 90x but not definitive, not visible at 150x, seeing does not sustain 150x.
Documented: Magnitudes 5.7 & 9.8 at 13.1"; 5.7 & 6.9 at 63.6"

B 755
No split.
Documented: Magnitudes 5.8 & 6.9 at 1.5", 6.0 & 11.5 at 21.4"

CPO 6
No split.
Documented: Magnitudes 8.2 & 8.2 at 1.1"

Dun 29
Took some effort to find, once found easy split of an almost equal double.
Documented: Magnitudes 7.7 & 8.0 at 64.6"

HJ 3860 (2230)
Nice unequal double orange and green/blue.
Documented: Magnitudes 7.3 & 8.8 at 8.6"

HJ 3849
Nice, wide, choice double that is unequal with pale orange and dull orange components.
Documented: Magnitudes 6.7 & 8.1 at 39.5"

COO 34
Nestled as the middle star in a string of 3 with a fainter set of 3 stars nearby. This double is challenging and can just get secondary at 60x.
Documented: Magnitudes 9.0 & 10.2 at 5"

HJ 3831
Two equal, very tough, just split at 60x, looks like a peanut most of the time.
Documented: Magnitudes 8.7 & 8.8 at 2.3"

HJ 3827
Same FOV as HJ 3831, easier but fainter almost equal.
Documented: Magnitudes 9.4 & 9.6 at 23.7"

CPO 5
No split.
Documented: Magnitudes 8.4 & 8.8 at 1.6"

HJ 3807
No split.
Documented: Magnitudes 8.2 & 10.1 at 4.5"

HJ 3781 (2315)
Unequal double, choice, secondary faint, strong aqua colour, main orangish.
Documented: Magnitudes 8.0 & 9.4 at 16"

Dun 22
Nice almost equal pair, hint of yellow (primary) and green (secondary) but hint only.
Documented: Magnitudes 7.2 & 7.8 at 7.3"

Clouds at 2320 closed session down.
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  #2  
Old 05-01-2009, 01:48 PM
Rob_K
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Great report Coen, a lot of interesting things there! Like your work on the doubles, something I have never really got into...

Cheers -
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  #3  
Old 05-01-2009, 02:58 PM
Smirnoff
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nice work there Coen! Doubles make good targets during moon periods, something I really should get into coz there's lots of nice colourful pairs out there
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  #4  
Old 05-01-2009, 03:30 PM
Coen
"Doc"

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Join Date: Oct 2008
Location: Adelaide, Australia
Posts: 180
Thanks for the comments. Never know when you write notes whether they of any interest either to someone else or even yourself a few days/years later.

There are doubles and there are doubles. There are plenty of lists around and the WDS database is available and readily searchable. Unfortunately the lists are often Northern Hemisphere focussed although the is a list of 110 Southern Doubles compiled somewhere on the web.

At this stage I am using the doubles as a way of:
- getting familiar with a constellation
- training myself
- getting comfortable with the telescope arrangements i.e. techniques, what I do and don't need and other such things
- star hopping
- and lots of other little bits and pieces

I'll ultimately get a bigger scope, something around the 4 to 6 inch in a refractor or 8 to 12 inch in a reflector/cass/mak; we'll see.
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  #5  
Old 06-01-2009, 03:01 PM
Coen
"Doc"

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5 Jan 2009 Average seeing, bit over quarter moon.

Finish off (mostly) my list for Columba.

HJ3760 (2215)
Revisit this triple and it is easy to split the main pair making a pleasing view. The fainter 3rd of the system has a hint at 60x averted and jumps out
with averted at 150x.
Documented: Magnitudes 7.7 & 10.6 at 29.1", 7.8 & 8.4 at 7.4"

HJ3740 (2220)
Cleanly split and a nice uneven pair, initial impressions of colour were pale yellow and orange but after viewing the secondary takes on a greenish hue.
Documented: Magnitudes 6.8 & 8.3 at 23.7"

HJ3728 (2230)
Star hop from HJ3740 to the nice globular NGC 1851 and from there to
HJ3728.
The magnitude difference between these two makes them a challenge with a hint at 60x averted, stronger at 90x in the correct orientation and at the correct
distance. Primary a yellow-orange.
Documented: Magnitudes 6.8 & 10.1 at 10.1"

Daw 38 (2240)
Very faint sky is bright, saw on map, tried it, looked it up afterwards and well, no hope.
Documented: Magnitudes 10 & 10.4 at 1"

HJ3735 (2245)
Two almost identical little orange orbs cleanly separated and very nice with a bright star nearby.
Documented: Magnitudes 8.2 & 8.4 at 7.2"

HWE 12 (2255)
Faint and impossible to say as conditions not too good.
Documented: Magnitudes 8.9 & 10.0 at 2.3"

HJ3745 (2310)
Very hard to say.
Documented: Magnitudes 8.5 & 10.5 at 13.3"

COO 32 (2315) (also INN 740)
No split.
Documented: Magnitudes 8.6 & 10.6 at 13"

Conditions too poor.

Skywatcher refractor a nice telescope, tend to find colours are often hard, could be my aging eyes.
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