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Old 19-01-2009, 12:59 PM
Coen
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70mm Refractor - Pic Tour

6 January to 16 January local time +10.5 to UT

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

If eyepiece unspecified it is 60x 15mm GSO.

Tour of Pictor

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

Tri-Atlas Hybrid (M) 185,186,205

Observing list compiled from CNebulaX (CNX), Taki's double star list and consultation with the WDS database. Sometimes star found on map by telescope and attempted.

Post observation checking also incorporating StarCalc (SC) and Cartes du Ciel (CdC)

6 January, seeing not too bad, just after 1st quarter moon

HJ 3822 (2220)
Lovely! Unequal wide pair, beautiful yellow and orange red within a pleasant star field. Faint star located not far from the pair. Later consultation with an atlas gives the faint star (when recorded) as either 10.6 (CdC), 11.3 (CNX) (not in SC) but not classed as a variable.
Documented: Magnitudes 6.6 & 7.6 at 56"

Dun 20 (2225)
Nice wide pair of almost equal magnitudes. Hint of yellow on main, secondary white with hint of pale blue. A bright pair that dominates the FOV.
Documented: Magnitudes 6.3 & 6.7 at 38"

Dun 18 (2232)
Another beautiful almost equal pair about 1/2 magnitude difference. White perhaps pale yellow & soft orange, dominates somewhat sparse field.
Documented: Magnitudes 5.6 & 6.2 at 13"

Inn 342 in Dor (2235)
Faint double in same FOV as Dun 18. Can just split as reasonable seeing. Looks like pair of faint orange almost equal orbs split clear at 90x. Unexpected nice pair.
Documented: Magnitudes 8.3 & 8.8 at 2.9"

Inn 274 (2245)
Attempted. Faint star reasonable distance away which hints at being a double, perhaps or an artifact of seeing. Attractive "Eiffel Tower" type grouping nearby. Sketch made. Later consultation is did not split Inn 274 and the faint star is indeed a double. However the documented magnitudes are 11.5 and 11.8 so perhaps I saw them but most likely not. Inn 274 itself was not split.
Documented: Magnitudes 8.5 & 10.1 at 3.4"

There is an attractive star field around eta 1 and eta 2

HJ 3715 (2255)
Very unequal pale yellow and dark blue pair that are clearly separated but the secondary is a challenge due to the magnitude difference. Double located in an attractive area around eta 1 and eta 2.
Documented: Magnitudes 7.2 & 9.1 at 10"

Unknown (2315) later consultation is most likely HJ 3681
Very unequal and very wide.,
Documented: Magnitudes 6.8 & 10.6 at 49"

COO 23 (Inn 740) (2325)
Took effort to find and confirm. Unable to resolve.
Documented: Magnitudes 9.0 & 9.5 at 0.6"

HJ 3793 (2340)
No resolution, took a while to confirm. Tried 60,90 and 150
Documented: Magnitudes 7.1 & 10.3 at 13"

Dun 21 (2345)
Bright and very wide pair almost equal yellow and white. Brightish star nearby has a faint companion orientation indicates Inn 62.
Documented: Magnitudes 5.5 & 6.7 at 198"

Inn 62 (2345)
Wide very faint companion. Did not split Inn 62. Faint companion documented at 11.8 magnitude.
Documented: Magnitudes 8.8 & 9.3 at 0.8"

HJ 3784 (2350)
Nice close unequal double, yellow and blue green, at 2355ish a satellite crosses the FOV.
Documented: Magnitudes 7.6 & 9.4 at 5"

HJ 3797 (2355)
Easy wide unequal double on fainter side, initial impressions are orange and deep blue.
Documented: Magnitudes 8.2 & 9.4 at 55"

HJ 3803 (0000)
Unequal wide pair, can just see the faint secondary.
Documented: Magnitudes 7.9 & 10.0 at 20"

11 January attempted but large moon and windy conditions meant abandon after 1 star seen.

HJ 3763 (2145)
Star hopped across from Columba. Bright sky. Easily split with 25mm basic, seeing is bad. Initial impressions are yellow and green. Tried 15mm wide. Nice pair that needs darker skies to enjoy.
Documented: Magnitudes 8.3 & 9.0 at 12"

15 January seeing and transparency seem to be good.

Not in Pic, started in Dor with:
Dun 26 near eta Dor (2245)
Nice uneven double, not very strong colours, maybe yellow and green. Nice star field with eta Dor very close.
Documented: Magnitudes 6.9 & 8.7 at 20.6"

NGC 2257
Very faint motely background, something there but what? Very large taking up, it seems, around 30' with some brighter stars super-imposed over it.
Documented as a 13.5 magnitude globular cluster that is part of the LMC although there is some confusion as to its size and whether it is indeed a globular cluster. It is unlikely I saw it so what did I see?

Now in Pic:
HJ 3843 (2300)
Tough unequal pair seen at 60x just, whilst separation is wide, 2nd faint easier at 90x maybe orange and blue. Nice star field.
Documented: Magnitudes 8.7 & 9.7 at 12"

LPO 6 (2305)
Faint double almost same field as HJ 3843. Not quite equal components. Located at the head of a kite-type arrangement of stars. Hint of a 3rd star not far with averted vision is it real? Almost in line with the other 2.
Documented: Magnitudes 9.4 & 9.9 at 11"

Dun 27 (2310)
Attractive unequal pair bright and wide, not much colour perhaps pale yellow and orange, flanked by friends.
Documented: Magnitudes 6.5 & 7.6 at 34"

JSP 101
More of an arrangement of stars that is nice. There is a faint star nearby (9.5) but the designated faint secondary was not viewed.
Documented: Magnitudes 6.5 & 10.6 at 16"

HJ 3874 (mu Pic) (2320)
No chance
Documented: Magnitudes 5.6 & 9.3 at 2.5"

R69 (2330)
Too hard, as in too faint for the conditions.
Documented: Magnitudes 9.8 & 10.2 at 6"

HJ 3861 (2335)
Very tought not at 60 or 90x.
Documented: Magnitudes 9.3 & 9.5 at 1.6"

NGC 2132 (2345)
Not much to see, a few stars - documented as a collection of stars rather than a cluster.

HJ 3802
On way to HJ 3787 and HJ 3777. Attractive grouping around this star. Saw some 11th magnitude stars that are nearby but not the secondary. Mistook one of the 11th magnitude stars as the possible secondary.
Documented: Magnitudes 8.4 & 10.6 at 7.6"

HJ 3787 (2350)
Wide pair with faint secondary, reasonably clear with averted but not so with direct at 60x. Similiar for 90x.
Documented: Magnitudes 7.8 & 10.0 at 25"

HJ 3777 (2355)
As with HJ 3787, wide and unequal can only see secondary averted when it then jumps out. Primary is bright.
Documented: Magnitudes 6.5 & 10.6 at 16"

Moon up, stop viewing program to do some general viewing in Carina region.

16 January very bad seeing conditions

HJ 3789 (2150)
Unequal pair that can just be split due to the poor seeing. Located in an attractive string of stars.
Documented: Magnitudes 8.6 & 9.0 at 9"

Viewing abandoned due to poor seeing, suspect not easily noticed high cloud.
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  #2  
Old 20-01-2009, 10:22 PM
Rob_K
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Another nice report Coen, well done! You certainly got a lot out of that session!

I've thought of doing a bit of doubles viewing, but in light of reports like yours I find it very confusing. There seem to be so many catalogues and designations that it just seems too hard. Why don't people use the actual star designations? LOL, I realise that there are several catalogues commonly used there too, but at least it is easy to do correlations. If I knew HIP66450 was a nice double, I could look in my copy of Starry Night and find it. HJs & COOs & JSPs mean nothing to me...

Is this a case of too many 'common names'? I'd very much like to hear ngcles' comments on this. Not trying to be contentious or anything on this, I really don't understand. Do the strange doubles naming conventions serve any useful scientific purpose, or are they simply observing conventions?

Cheers -
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  #3  
Old 21-01-2009, 08:41 AM
Coen
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I too find the various catalogues confusing especially when different atlases use different conventions.

I use CNebulaX to plan which doubles to look at but it too has multiple reference names to the individual stars and then the Tri-Atlas, made from the CNebulaX maps sometimes has a different label on the double. Makes tracking down some of them interesting. An issue with CNX is that multiple stars (i.e. 3 or more) are not neatly presented in the planning component.

The ultimate double star resource is probably the Washington Double Star catalogue - download in one of many formats including a MS Access database with queries, about 24MB or so. Doing a search of that gives many and varied naming conventions. Issue with the WDS is that it gives RA/Dec and then you have to go find it on your map set. CdC has WDS as a catalogue within it but searching that can be a pain i.e. not straight forward or at least not to me. CdC does have some other features that make it handy for subsequent reference.

In general it seems that you who discovered it and wrote it down - well your naming conventions became a guide. Or it is attributed to the person who grouped them. E.g. the Dun series, Dunlop did not discover all of them but he had a list that eventually became Dun 1, Dun 2, ... in general I like the Dunlop doubles. There is also Innes series and HJ seems to be based off John Herschel's records.

As you say it makes it interesting when you have other catalogues such as the Tycho Double Star, Hipparcos, etc. If your goto database only operates off SAO then that makes it fun too. Simbad/Vizer becomes your friend and the work load climbs.
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Old 21-01-2009, 09:27 AM
Rob_K
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Thanks Coen! I suppose my main point was that in an already complex hobby, we have to add further layers of complexity! In a sense, it also means that 'double star observers' have created their own little world that it is difficult to get into without arming oneself with the paraphernalia, while if the conventional star designations were used it would be 'open' to everyone!

Your point about the goto is taken - but of course co-ordinates are not much good if you haven't got goto. If you're using an undriven dob or other scope without goto you are much more reliant on accessing & recognising the field, usually with the popular planetarium programs. In Starry Night you can switch on a doubles (multiples) layer which can help in isolating the culprit. But you still have to undertake the 'conversion'.

So give me NGCs & HIPs & TYCs LOL, and I'll put the rest down to "doubles aren't meant to be easy"!

Keep up the good work anyway Coen - even if I'm too lazy to do the hard yards on doubles, I can still sit back and enjoy other people's doubles observations!

Cheers -
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Old 21-01-2009, 10:43 AM
Coen
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Even with DSOs it can be fun with NGC, RNGC, PPM, Col, IC, ...

There is a journal for doubles stars that folk might find interesting or even wish to contribute towards: http://jdso.org/
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Old 21-01-2009, 04:39 PM
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ngcles
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The desert blooms ...

Hi Coen & All,

Well it just shows to go ya -- I have long regarded Pictor as probably the most arid "desert" in the far southern sky. My total log entries for Pictor are just 10! (Mind you, Hydrus and Octans are hardly larger)

But you've made the desert bloom. Well done!

I must say, I was quite surprised how few pairs I've got observations of in Pictor. The sum total is -- 1 (that you also include in your notes) -- Dunlop 20 or Theta Pictoris (fairly nearby to Beta Pictoris).

My note of Dunlop 20 from 1997 using 25cm is:

x86 34' TF. Mags 6.3 & 6.8 Sep 38.2" PA 287. Wide and easy pair about 40-50" in PA 290. A is about 1/10th mag Br than B. Both are cold white.

So I saw the colours a little different to you -- but hey, colour is a very subjective thing when viewing through any 'scope. The spectral types are A0 (V) & A2 (V) indicating that both stars are similar to Sirus in nature -- ie as white as the driven snow. But remember always to say it how you see it! If that's how you see it, that's the way it is for you!

I've already commented about the NGC 2257 thing the other day, but just looking at your observing note, you indicate the object you saw was about 30 arc-mins diameter -- this certainly does not fit NGC 2257 which is only a bit over 1/10th that size. So it would seem likely you didn't see NGC 2257 I'd reckon.

As for the cattle-dog issue Rob K -- Coen has hit the nail on the head. As each observer makes discoveries he/she makes a new catalogue which is eventually published. Often we see one observer by accident include pairs previously discovered by others -- so there is quite a bit of cross-over. I'm not the double star expert (or any other sort of expert either I assure you) by any means -- to get a definitive (and comprehensive) answer the man to ask is Enchilada!

As noted the closest thing to a RNGC for double star observers is the WDS. Just use a search engine to locate a downloadable WDS and you will get a huge file!


Best,

Les D

Last edited by ngcles; 22-01-2009 at 01:23 PM.
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Old 22-01-2009, 09:01 AM
Coen
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Thanks for the info especially regarding Dunlop 20.

There are a few other doubles in Pictor but they were getting too faint for my little refractor and the light pollution. It seems, while I can see down to somewhere between 11.5 and 11.8 in magnitude, I think for pairs I would not want to go fainter than about 9.5 for the primary. Still that gives enough doubles outlast my lifetime.

I am still having fun getting the hang of estimating sizes of objects in the eyepiece - need to work on it a bit more.

Les, out of curiosity, and sorry if it has been addressed previously elsewhere on the forum, do you keep your observing entries electronically?

Regards,
Coen
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Old 22-01-2009, 01:43 PM
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ngcles
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Notes

Hi Coen & All,

Quote:
Originally Posted by Coen View Post
I am still having fun getting the hang of estimating sizes of objects in the eyepiece - need to work on it a bit more.

Les, out of curiosity, and sorry if it has been addressed previously elsewhere on the forum, do you keep your observing entries electronically?
Yep, the sizes, seperations etc can be tricky and really all you can do is a good guesstimate. Nearly all my observations of pairs are with the old 25cm any my 31cm which was mounted on a German equatorial. So, it was fairly easy to estimate the PA to within 10 degrees just by watching diurnal motion with the drive switched off and using the Dec slow motion. Separation is quite another thing and the best you can do (without a micrometer of some sort) is a good, honest estimate. Then note the colours you can see (if any) and the mags difference (if any).

As for an observing log, yes I keep mine electronically on a laptop and there are four backups made every month. One on the home P.C, one on a thumb-drive and another on C.D that is in the safe at my work. Yes I know I'm "retentive" in that respect but to me it is now more valuable than much of the equipment -- equipment can mostly be replaced.

I went over from hard-copy to electronic a bit over 4 years ago when I had a few months off due to a work-injury. I needed something to do so I bit the bullet, bought the software and typed in all it.

At that stage I had six lever-arch files full of paper with three entries per page -- cross-referenced and indexed. It was getting to the point that I couldn't take my log observing with me because it just wouldn't fit in the vehicle with the 'scope, books, guides etc etc. It took nearly three months to type in (worth every minute) and has obviously grown a little bigger since then! I am currently thinking about changing-over from one software to another (won't name names) that I think is better but not sure yet.

The one I'm thinking of changing to has said they will convert my log to their format as part of buying (if I go that way).

I'd encourage anyone observing to keep a log of some sort -- however you do it is up to you. It is great to look back on!


Best,


Les D

Last edited by ngcles; 22-01-2009 at 04:08 PM.
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Old 01-02-2009, 11:13 AM
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Another nice report Coen.

I aggree when it comes to estimating sizes of objects in the eyepiece, to achieve accuracy a reticle/astrometric eyepiece or something like that is neccessary. Knowing your eyepiece's TFOV is the key to getting a decent estimate of object.
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