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My 1,000th NGC

acey

By acey
in The Astro Lounge

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acey

acey

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Last night I passed a personal milestone by viewing my 1,000th NGC object. It was NGC 1046, a small galaxy in Cetus. Actually I was more concerned about trying to stop my flextube and maps blowing away in the wind to notice I'd scored my millennium - I only realised it this morning while spreadsheeting my observing notes. I logged my first (NGC 2287, or M41) on Christmas Day 2001 and my 900th in August this year.

Only another 6840 to go....

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celestron8g8

celestron8g8

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Congrats to you for some fine observing ! I have always advised ppl to not let imaging get in the way of using your scope . Observing is as or more important than imaging cause it allows you to get to know the night sky and all the DSOs' . I use to observe alot more than i imaged mainly because i'm not a very good imager and i have basic equipment but now i do less because the LP has doubled here as to what it use to be 5 yrs ago :eek: .

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acey

acey

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OK, now tell us why you do it ;-)

"Because they're there!" :)

I do wish I could up the pace a bit: I won't be able to lug a big scope forever. Would help if I didn't have a 40 minute drive to my dark site every time I use it. Just as well I haven't been logging my petrol consumption! :eek:

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acey

acey

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must have took alot of dedication

Or madness! Cheers Mick and best of luck for your own observing odyssey - I was very pleased to add G1 to my "non-NGC" list the other night thanks to your tip.

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mdstuart

mdstuart

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Amazing..makes my 400 galaxies seem like only a few...I will go back and try your Andromeda NGC 68 group..I think I cannot see them with my 10 inch as they would be beyond me.

I like NGC404 next to Mirach in Andromeda though..

Really well done. Do you log how bright the galaxies are to you on a scale like just wirth averted vision, held with direct vision etc..If you have data I would love to compare to my recordings and then share it with you?

Mark

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acey

acey

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Well done on yours Mark and I'm sure you'll soon catch up at the rate you're going. My records are hand-written notes; these days I record each session on loose A4, then copy my notes and any sketches more neatly into a (dry!) notebook afterwards, entering the date of the observed object into Excel, and into my copy of the NGC:

Ngc 2000.0: The Complete New General Catalogue and Index Catalogues of Nebulae and Star Clusters by J.L.E. Dreyer: Amazon.co.uk: Roger W. Sinnott: Books

From the book or spreadsheet I can work back to my notebook, and if necessary to the original A4 sheet (which gets kept in a folder). For each galaxy I record its brightness on a scale of my own making. In what follows, "sweepable" means that the object would be noticed even if you weren't looking for it, but simply swept through the field (a subjective judgment). "Low power" in my case means x47 (a 32mm Plossl in my 12" f4.9), "high power" means anything above x188 (the top power of an 8-24mm Baader zoom; I also use a 6mm TMB planetary and 4mm Nirvana) and "medium power" is anything in between (for which I use the zoom). I view all objects with both direct and averted vision; if the object is visible only with averted vision then I note this.

Extremely Easy (EE): sweepable at low power

Very Easy (VE): not seen at low, but sweepable at medium power

Easy (E): sweepable at high power

Moderate (M): once found in high power, can be held steadily (with direct or averted vision)

Difficult (D): object sometimes lost from view

Very difficult (VD): object mostly lost from view

Extremely difficult (ED): seen only in fleeting glimpses - but definitely there.

This of course assumes observations under equal conditions: I use a single scope at a single site that typically has a sky brightness of 21.1-21.3 mag/sq-arcsecond (I record measurements with a Sky Quality Meter during each session). If the moon is present then I record its phase; its elevation can be recorded using a Wixey, and if the DSO in view is low in the sky (hence weakened by atmospheric extinction) then I may record its elevation too. If overall transparency is impaired then I note this (though I do not use a formal scale). My brightness scale suits the sort of objects I currently look at (typical NGCs); I've been using it for about a year and am considering modifying it from a 7- to a 6-point scale (as used by John Herschel for the General Catalogue), so that I could make some concordance between my observations and the GC/NGC. Doubtful or negative sightings are recorded thus:

P (possible): a suspected object that couldn't be confirmed (I sketch its position and check afterwards with DSS images; sometimes it turns out to be a valid sighting, sometimes it becomes an X).

X: object not seen - and not counted! But worth noting that it has been attempted.

I also record any unusual features where applicable: apparent foreground stars, mottling, uneven brightness etc. With regard to other galaxy data I've not been particularly systematic, but I plan in future to use a graduated scale analogous to that used for visibility. To this end I've been looking at John Herschel's paper on his re-observation of William Herschel's catalogue; that paper gives diagrams showing exemplars of bM, mbM, etc. Basically the problem is to account for the "two-zoned " appearance of many galaxies, where there is a variable relationship of brightness and extent between inner and outer zones. An easily memorised and applicable scale for these parameters would be useful to me: I've never been able to get along with the NGC scale (which was in any case variably applied by the NGC observers).

In recording the size and elongation of galaxies I have likewise been vague. Herschel etc used micrometers to measure galaxy sizes and position angles. I attempted to use a Meade illuminated reticle eyepiece but this failed for 2 reasons: 1) the LED was too bright (and the etching too small to be used without illumination); 2) it's very hard to use with a dob, especially at high power. I admit I find it very hard to distinguish galaxy sizes in any consistent way. I note things such as "large", "small" etc, but other than extreme cases, I know that I'm not consistent. I've considered the method used by Galileo (and revived in a different way by W Herschel with his lamp micrometer) of comparing the object in view with one seen near at hand using the other eye. Another possibility would be to use cross hairs on the eyepiece. Experts such as Luginbuhl and Skiff recommend judging size from the proportion of filled field, but I'm hopeless at it - and wide-angle eyepieces make it all the more difficult. Similarly with orientation, the old masters used instruments to find position angles while modern dob users generally rely on judgement. I know from my sketches that even in judging West (the direction in which objects are moving across the field of view) I can have large errors, so I judge elongation no more accurately than NE-SW etc - and often get it wrong (especially at 3a.m. when I'm tired!). Again, cross-hairs could be a good idea here. The NGC compilers were often very terse in their descriptions (the other night I noticed that one object about which I had jotted a few details was described in the NGC simply as "F"). When moving through a rich field of galaxies I will sometimes content myself merely with its brightness, as the professionals once did. I try to keep my notes (unlike this post) as short and to-the-point as possible. In that way I can spend more time observing, less time note-taking.

Everyone has their own interest and approach; for me, the question of galaxy classification is of particular interest, which is one reason for wanting to systematically survey large numbers of objects (plus it's fun!). I don't have any system for other DSOs; I note with clusters if they're large, compressed etc, and if there is any notable shape, but I haven't attempted any detailed classification; similarly with nebulae. Those objects in any case constitute the minority of observations: the NGC is heavily dominated by galaxies.

My observing list currently consists of the following:

Objects in the Herschel catalogue, minus classes II and III (chosen because of relatively high brightness and great historical significance)

Objects in the Hickson catalogue (chosen for aesthetic appeal)

Objects in the Arp catalogue that are in the NGC (chosen for their potentially unusual features)

Objects in the Arakelian catalogue that are in the NGC (chosen for their high surface brightness)

Objects in the Revised Shapley-Ames catalogue (chosen for their high brightness).

I have them printed out and ordered by Uranometria chart number, so that when I begin an observing session I can simply choose a well-placed chart and start working through them. If there are NGCs marked in the vicinity of my listed objects then I have a go: in this way I pick up many Herschel class II or III, plus other objects.

I am of course always happy to share my observations with anyone; though there are far better and more authoritative sources. For anyone seeking visual DSO data, the principal (online) source is the NGC itself: The NGC / IC Project - Home of the Historically Corrected New General Catalogue (HCNGC) since 1993 An invaluable reference book for bright DSOs is: Observing Handbook and Catalogue of Deep-Sky Objects: Amazon.co.uk: Christian B. Luginbuhl, Brian A. Skiff: Books.

Good luck and clear skies,

Andrew

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mdstuart

mdstuart

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Thank you for the amazingly detailed description of how you record galaxies. My main facination has been "brightnes" as clearly magnitude gives no real inticator. Even sbr can be misleading as I can see some 13.5's but not others..

So I devised a scale and have classified all the objects I have seen from M31 right down the messiers then the bright NGC's like 2841 and 7331 and then on to the fainter ones..

6 on my scale is very easy with direct vision and low power, probably your sweepable?

7 is just held with direct vision, so not to challenging but reasonably hard to pick up. Probably visible at low power when you know where you are looking etc...

8 is for all those tough ones that you can only see with averted vision..This accounts for about half those I have seen...

So looking at my November log, 1161,410 are both 8..1052 & 1084 are both 7 and 936 was a 6..How does this equate with your observations..

Mark

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