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Old 08-04-2009, 11:58 PM
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ngcles
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Observing Report 29 March 2009 - NGCLes

Hi All,

Well its nearly a fortnight ago but I thought I'd post some observations made from my nearly-dark site at Bargo in highlands southwest of Sydney on the night of th 28th and morning of 29th March 2009.

There was hardly a cloud in the sky all day which only made me suspicious given the bad run of cloud we've endured over the last several months, it kinda looked like a trap -- to entice me 100km away and then when I was all set-up and ready; call in the clouds. This time there was no deception, trickery or teasingon the part of mother-nature. Particularly as it was Earth-Hour.

And, while we're on the subject of Earth-Hour, the SQM readings for the night started out at 21.1 and ended at 2am at 21.4 with a linear improvement in-between. No bumps up or down between when the lights went off or on. Just like every other Saturday night. It seems Earth-Hour made no apparent difference at all as compared to any other moonless Saturday night there.

On the other hand the seeing was wonderful -- the best I've seen from Sydney and its environs for 2 to 3 years which made Saturn a real treat
at x247, x317 and x371. We observed a shadow transit of Titan which was exquisite. With Titan sitting low in the glare of bright Saturn Titan was occasionally seen as a disc and was a clear reddish-fawn colour. I could also still see long glimpses of the Cassini division despite the rings being closed right-down.

The Homunculus was stunning at x465 with all the gross detail in the iconic Hubble image clearly visible and some of the fine detail too. Besides the dusky blobs in the brighter lobe, the edges of the brighter lobe had all sorts of lumps and dings in it -- its boundary is really quite irregular in shape.

One other surprising observation was of NGC 3918 -- the "Blue Planetary" in Centaurus nr Crux which is detailed below. I managed to get through about 40-odd galaxies in the end -- less than I expected but I 'wasted' a lot of time gawking at Saturn!


x185 27' TF

IC 2532 Galaxy *
RA: 10h 00m 05.4s Dec: -34 13' 41"
Mag: 13.9 (P) S.B.: --- B-V: --- Size: 1.5'x1.2'
Class: (R')SB(rs)a P.A.: 38 Inclination: --- R.V.: +2900

NGC 3087 Galaxy *
RA: 09h 59m 08.8s Dec: -34 13' 30"
Mag: 11.6 (V) S.B.: --- B-V: +1.05 Size: 2.1'x1.9'
Class: E+: P.A.: 45 Inclination: --- R.V.: +2673 Source: RC3 *

IC 2532 is found about 10' E of NGC 3087. -87 is a small, round mod bright eg in the middle of a small tri of mag 12-13 *s. Around about 1' diameter growing slightly at first to centre and then at centre steepening to a considerably brighter core zone. IC 2537 is 10' E near a small group of faint *s. For mag 13.9 it seems to be faint and LSB. Difficult to see structure, seems round, 30" diameter with a slight central brightening and has a 10th mag * just outside the N - NE halo. Possible faint spot or faint stellaring in the centre.



x185 27' TF

IC 2536 Galaxy *
RA: 10h 03m 29.8s Dec: -33 57' 04"
Mag: 14.5 (P) S.B.: --- B-V: --- Size: 1.9'x0.4'
Class: SBc pec sp P.A.: 45 Inclination: --- R.V.: +5384 Source: RC3 *

ESO 374-23 PGC 29109 Galaxy *
RA: 10h 02m 49.9s Dec: -33 57' 12"
Mag: 15.2 S.B.: --- B-V: --- Size: 0.9'x0.3'
Class: L P.A.: 39 Inclination: --- R.V.: --- Source: PGC *

-36 is a pretty small, edge on eg which is found in a mod well-populated field. There is a small oblong or rectangle of of mag 12 & 13 *s to the NE of the eg and the long sides of that point in the direction of -36. There is a mag 14 * not far off the S flank. Can't quite hold it consistently with DV., probably 1.5' x 15" in about PA 45 with a weak brightening to the centre.

ESO 374-23 is a similar 1/2-'scale eg in the same PA 10' westward but fainter.



x185 27' TF

IC 2539 Galaxy *
RA: 10h 04m 16.1s Dec: -31 21' 45"
Mag: 14.0 (P) S.B.: --- B-V: --- Size: 1.9'x0.4' Class: SA(s)bc:
P.A.: 25 Inclination: --- R.V.: +2850 Source: RC3

A faint but beautiful eg, small elong lens-shaped 1.25' x 10" in about PA 30 and has not far off the SW tip ...

then see the optical transient. Exact transcript:

I've just seen something highly unusual in the eyepiece and I've got to describe it I've just seen a star brighten and fade in just a few seconds. There are three stars near the EG on the W flank at the SW end. Nearest the core is a mag 15 star, then an even fainter perhaps mag 15.5 * which is intermittently visible, and then the 12th magnitude one at the SW tip. The first of these which is visible nearly all of the time AV brightened over two or three seconds to be almost as bright as the 12th mag * at the tip. Est Mag 122.6 12.7, Stayed that brightness for a few seconds and then faded back to "normal" in about 1/2 the time it took to brighten. (see below the post on IIS). Total time for the event is slightly uncertain, I'd estimate 6-7 seconds, 10 at most 5 at least.

Back to the eg, it is in PA 30, with a slight broad concentration to centre but no evidence of nucleus.

The following thread here:

http://www.iceinspace.com.au/forum/s...ad.php?t=43028

refers to this apparent optical transient and the text below appears there:

Hi All,

I'm hoping for your help on this one.

Last night I was observing the small faint nearly edge-on galaxy IC 2539 in Antlia at about 9.30pm local time (10.30 UT) on 28032009 at Bargo NSW. The conditions were very good. I'd rate the seeing at 8/10 and somewhere around 0.7" or possibly slightly better. The transparency I'd rate as a 7 verging on 8/10 with a SQM-L showing a reading 10mins previous of 21.12 equating to a ZLM about 6.2. I was observing at x185 with a 12mm TII with an 18" f/4.9 with Argonavis DSC and Servocat drive and goto.

A POSS II red 5 arc-min square image of the galaxy which shows the position of the possible transient is here:

http://stdatu.stsci.edu/cgi-bin/dss_...e&fov=NONE&v3=

There were three stars near the galaxy that I could see while observing -- TYC 7170-1368-1 is on-axis with the galaxy to the SW -- about 1.4 arc-mins from a rough centre of the galaxy in PA 208 has a magnitude of 12.06. I could also see two very faint stars just off the W flank of the SW end of the galaxy. These were USNO 0525-12640582 at mag 15(??) and USNO 0525-1264033 at mag 15.75.These two are respectively -- 39" distant from centre in PA 238.9 and 56 arc-seconds in PA 225.Both of these were very faint in the eyepiece and averted vision. On the image, there is a further faint star between TYC 7170-1368-1 and USNO 0525-1264033. This is USNO 0525-12640453 (mag 16.95) and was not seen.

As I was observing the galaxy, I noticed the star USNO 0525-12640582, or at least at a position coincident with that star brightened quite a bit to become almost as bright as TYC 7170-1368-1. The apparent brightening ramped up evenly over about 3 seconds and remained apparently constant for about another 3 or 4 seconds and then faded somewhat more quickly back to "normal" in perhaps about a second. I'd estimate it reached mag 12.7 or thereabouts -- I didn't get long to make the estimate. Nothing else in the field or near the galaxy showed anything similar at the same time (or any other time) -- this was the only object to do this. No movement in the apparent transient was detected/observed while the event occurred.

I am a reasonably experienced observer. No alcohol consumed in the previous 14 days. Illicit drugs not involved. No prescription or non-prescription drugs for at least 14 days. The equivalent of 1 cup of normal strength tea consumed about 10 hrs before -- caffeine apparently not an issue. 8 hrs sleep the previous night. Had been awake just 11 hrs before making this observation. Not feeling tired at all. Had only just started "serious" observing 10 mins before.

I believe this apparent observation is of a non-spurious nature -- of course I have no back-up and there is no objective corroboration. I feel pretty confident in the observation. The event lasted at most 10 seconds, probably more like 6 or 7 and there was no time to gain confirmation from other observers. I am unable to say whether it was the star that brightened or something in the background or foreground at a coincident position caused the apparent observed brightening.

I've never seen anything like this before. Should this be reported somewhere? Is there an apparent and logical explanation?

Feel free to comment.

And including a response from Brian Skiff re this:

Hi All,

I have received a reply from the highly respected Amateur now professional astronomer Brian Skiff that was posted on AMASTRO and it seems I'm not the first person to see this type of event (not with this star though!)

"Les' star is a 4".5 pair of similar brightness on DSS and 2MASS images. The southeastern component is slightly brighter, and the2MASS colors are those of a garden-variety K0 giant or mid-K dwarf; statistically in this part of the sky it is somewhat more likely to be a dwarf rather than a giant---both very ordinary sorts of stars,
in either case, so nothing obvious about the star colour.

I have seen just this sort of phenomenon once, just as Les
has described: that is, a perfectly ordinary field star flaring up
by several magnitudes, then fading back to the previous brightness.
My event was shorter, lasting only a couple seconds total.
Looking at my observing records, the star was GSC 5706-10179 =
UCAC2 28786920 (18 54 34.75 -08 49 55.6 [J2000, UCAC2]),
which is the mag 13 star on the WSW edge of the large planetary
nebula IC 1295. My notes (1981 March 15) say the star flared by
2.5 magnitudes, then dropped back, followed by irregular flickering
for a few seconds. None of the other stars in the field (obviously
a lot of them!) did anything. I was using a 25cm Newtonian at
the time. The star has the colour of a slightly reddened K-giant,
which are ubiquitous in the Milky Way.
Back in 1981 I knew about ordinary flare stars, but knew they
didn't erupt that fast (the timescale violates light-travel-time
and simultaneity principles). But we know now about funny stuff
happening on very short timescales, but getting them to happen
around plain-vanilla stars is problematic.

Since we are only beginning to explore this time-domain in
astronomy, it is not surprising there's no ready explanation for
these sorts of observations. I dunno what's going on, but aside
from probably being more fatigued (Scutum in mid-March from the
northern hemisphere....that's 4am!), I am just as convinced as Les
of the reality of what I saw. If it was something new in the field,
you could readily invoke physio/psychological effects, but the event
occurred on an identifiable star.

Watch this space!

\Brian"

So I might not have been dreaming after all ...

It seems too short to be a flare from a flare-type star (many K-stars and most M-type stars are flare stars). They normally last many minutes and it is waaaaaaay to slow to be a micro-lens event. No explanation yet. Maybe it is a rare and as yet unknown type of event -- who knows

If you've got a suggestion, give a hoy!



x185 27' TF

IC 2538 Galaxy *
RA: 10h 03m 56.2s Dec: -34 48' 28"
Mag: 14.6 (P) S.B.: --- B-V: --- Size: 1.5'x0.7' Class: SA(r)c pec
P.A.: 9 Inclination: --- R.V.: +8412

This eg is in a mod well populated field to the N of a mag 8 * and almost between 2 *s of mag 122.5 to 13. very small amorphous round blob of consistent SB and no central brightening.



pt 2 & 3 to follow ...
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  #2  
Old 09-04-2009, 12:00 AM
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ngcles
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Pt 2 cont ...

Pt 2 ...

x185 27' TF

IC 2548 Galaxy *
RA: 10h 07m 55.0s Dec: -35 13' 47"
Mag: 13.9 (P) S.B.: --- B-V: --- Size: 1.9'x1.6' Class: (R')SB(r)b
P.A.: 65 Inclination: --- R.V.: +4691 Source: RC3 *

This eg is found almost due E of a mag 9 * that is about 4' away. Very small diffuse looking eg with irregular edges, may be slightly elong in PA 15. Seems to have a quite LSB outer halo maybe 1.25' diameter and a small somewhat brighter small core area with a tiny stellaring at centre. Not too hard too see.



x185 27' TF

NGC 2911 ARP 232 Multi-Galaxy Sys *
RA: 09h 33m 46.3s Dec: +10 09' 05"
Mag: 12.5 (B) S.B.: 14.1 B-V: +0.96 Size: 4.1'x3.1'
Class: SA(s)0: pec P.A.: 140 Inclination: --- R.V.: +3167 Source: RC3 *

NGC 2914 Arp 137 Galaxy *
RA: 09h 34m 02.9s Dec: +10 06' 34"
Mag: 14.1 (B) S.B.: --- B-V: +0.95 Size: 1.0'x0.6' Class: SB(s)ab
P.A.: 15 Inclination: 4 R.V.: +3301 Source: RC3 *

NGC 2919 Galaxy *
RA: 09h 34m 47.7s Dec: +10 16' 56"
Mag: 13.6 (P) S.B.: --- B-V: --- Size: 1.7'x0.6' Class: SAB(r)b:
P.A.: 159 Inclination: 6 R.V.: +2490 Source: RC3 *

MCG +2-25-4 PGC 27175 Galaxy *
RA: 09h 34m 00.2s Dec: +10 01' 46"
Mag: 14.9 S.B.: --- B-V: --- Size: 1.0'x0.4' Class: S
P.A.: 153 Inclination: 6 R.V.: --- Source: PGC *

-11 & 14 are in the same ep field. -11 is the dominant member of the two and is mod faint only. Fair-size, maybe 1.5' diameter, round, poss slight elong in PA 0 in the outer halo it grows slowly to centre and there is a definite somewhat brighter core zone which in turn grows more strongly to a stellaring in the centre. There is a small Tri of *s between it and -14 to the SE only a few arc-mins.

-14 is only 30-40" diameter, round reasonable SB growing broadly and mod to the centre. S by 5' from -14 is MCG +2-25-4 that is no more than a 20" diameter of ephemeral mist.

-19 is one field NE of these three and is a quite elong eg, seems 2nd brightest of the 4. A bit brighter that -14 but has slightly lower SB. Seems to be in PA 160, fairly consistent SB long oval 1.5' x 20" indefinite edges but grows broadly and slightly to centre without zones or apparent nucleus.



x185 27' TF

NGC 2918 Galaxy *
RA: 09h 35m 44.3s Dec: +31 42' 20"
Mag: 13.6 (P) S.B.: --- B-V: --- Size: 1.4'x1.0' Class: E
P.A.: 65 Inclination: --- R.V.: +6789 Source: RC3 *

Is a quite small eg, probably only 30" diameter, looks like a very distant elliptical eg in a very thinly populated star-field, just a few faint stars -- 12th - 14th none close. Grows broadly and moderately to the centre without zones or core or nucleus. Seems to be round.



x185 27' TF

NGC 2927 Galaxy *
RA: 09h 37m 15.0s Dec: +23 35' 25"
Mag: 13.7 (P) S.B.: --- B-V: --- Size: 1.9'x1.0'
Class: SAB(rs)b P.A.: 155 Inclination: 4 R.V.: +7556 Source: RC3 *

This is an extremely dim field with just a few odd faint stars in it but the eg is to the W of a 8th mag * by 1/2 a field -- 14' as a small round pretty dim splodge of pretty LSB gossamer with hardly any central brightening. Seems to be round, about 30-40" diameter and diffuse edges.



x185 27' TF

NGC 2929 Galaxy *
RA: 09h 3m 29.7s Dec: +23 09' 40"
Mag: 14.7 (P) S.B.: --- B-V: --- Size: 1.4'x0.3' Class: S?
P.A.: 144 Inclination: 6 R.V.: +7549 Source: RC3 *

NGC 2930 Galaxy *
RA: 09h 37m 32.7s Dec: +23 12' 12"
Mag: 15.1 (P) S.B.: --- B-V: --- Size: 0.6'x0.4' Class: S?
P.A.: 135 Inclination: --- R.V.: +6599

NGC 2931 Galaxy *
RA: 09h 37m 37.7s Dec: +23 14' 26"
Mag: 14.9 S.B.: --- B-V: --- Size: 0.8'x0.6' Class: Sb
P.A.: 62 Inclination: --- R.V.: --- Source: PGC *

-29 is the major member here. It is about 8' N of a very long I tri of mags 10 & 12 * that points southward. Very small somewhat elongated lens shaped object in about PA 135 and with consistent SB, maybe 50" x 15" and no real central brightening -30 & -31 are 3 and 6' northward and even fainter tiny spots of most about 15" diameter. Both are very faint.



x185 27' TF

NGC 2943 Galaxy *
RA: 09h 38m 32.9s Dec: +17 01' 52"
Mag: 13.4 (P) S.B.: --- B-V: --- Size: 2.2'x1.2' Class: E
P.A.: 130 Inclination: --- R.V.: +8377 Source: RC3 *

NGC 2941 Galaxy *
RA: 09h 38m 24.3s Dec: +17 02' 41"
Mag: 15.2 S.B.: --- B-V: --- Size: 0.8'x0.5' Class: S
P.A.: 163 Inclination: --- R.V.: --- Source: PGC *

NGC 2933 (NGC 2934) Multi-Galaxy Sys *
RA: 09h 37m 54.9s Dec: +17 00' 55"
Mag: 15.0 S.B.: --- B-V: --- Size: 1.2'x0.4' Class: Sbc
P.A.: 32 Inclination: 6 R.V.: --- Source: PGC *

NGC 2946 Galaxy *
RA: 09h 39m 01.5s Dec: +17 01' 32"
Mag: 14.9 (P) S.B.: --- B-V: --- Size: 1.4'x0.4' Class: SB?
P.A.: 13 Inclination: 6 R.V.: +8953

-43 is the largest and brightest of these 4 and is not far from a small faint pair -- a few arc-mins SW from them. Not too bad, fairly diffuse looking Lowish SB looking blob, 40-50" diameter looks a bit irregular in surface brightness but generally grows broadly and slightly to centre and there is a small slightly brighter spot. -46 is 5' E and is very faint elong spindle in about PA 0, very small, 20-30" long faint and of LSB.

A similar distance W of -43 is -33 which is a very, very faint tiny streak of hardly to be seen mist about 20" long in PA 0 -- only occasionally visible.

-41 is not far outside the halo of -43 to the NW as an almost stellar-sized spot of gossamer no more than 10" diameter -- if that.



x185 27' TF

NGC 2958 Galaxy *
RA: 09h 40m 41.5s Dec: +11 53' 17"
Mag: 14.0 (P) S.B.: --- B-V: --- Size: 1.0'x0.7'
Class: S(r)bc P.A.: 10 Inclination: --- R.V.: +6639 Source: RC3 *

This isn't too hard to see in a thin field. Immediately visible. Fairly small, probably nearly 1' diameter, round lowish SB brightening broadly and slightly to centre azonally without apparent nucleus. May have an intermittently visible stellaring in the centre Seems sound.



x634 8'' TF

NGC 3918 Planetary Nebula *
RA: 11h 50 18.1s Dec: -57 10' 58"
Mag: 8.4 (P) Size: 19.0" Class: 2b Mag
C. Star: 15.6 R.V.: --- Source: Str-ESO

Astonishing seeing -- never seen detail in this thing like this before. Unfiltered at this magnification the disc of this PNe is about 15" diameter and a pale steely blue -- different from low magnification view.

Never seen it other than round before. There are two nearby stars mag 10 to the E 4' and the SE 5' and from those the nebula is elong in PA 0, more correctly, it is round but has two small, low protrusions from the disc N and S that make it look slightly oval in PA 0. The protrusions from the disc are slightly lower in SB than the rest of the disc and *occasionally* there seems to be a hint of some mottling over the disc. No Central star still. Lots of mag 15 & 15 *s in the field. Fantastic seeing.



x185 27' TF

NGC 3776 Galaxy *
RA: 11h 38m 18.0s Dec: -03 21' 13"
Mag: 15.8 S.B.: --- B-V: --- Size: 0.4'x0.3'
Class: Sb P.A.: 155 Inclination: --- R.V.: --- Source: PGC *

This is a very tiny and faint eg that took a little while to pin down because of that and the blank nature of the field. Almost stellar, 10-15" diameter splodge of very LSB fog with no apparent central brightening.



x185 27' TF

NGC 3843 Galaxy *
RA: 11h 43m 54.7s Dec: +07 55' 33"
Mag: 14.5 (P) S.B.: --- B-V: --- Size: 0.9'x0.4' Class: S0/a
P.A.: 42 Inclination: 6 R.V.: +5908 Source: RC3 *

This is a very small elong eg in PA 30 in a pretty barren field. There's no stars visible within 5-6' of the eg. Elong oval about 40 x 20" in PA 30 with a broad slight central brightening and a hint of a large, weakly brighter core-zone.



x185 27' TF

NGC 3914 Galaxy *
RA: 11h 50m 32.6s Dec: +06 34' 04"
Mag: 14.0 (P) S.B.: --- B-V: --- Size: 1.1'x0.5' Class: (R')SB(rs)b
P.A.: 40 Inclination: 5 R.V.: +6141 Source: RC3 *

This is pretty immediately visible, no real difficulty to see. It is pretty small, 40 - 50" diameter, round reasonable SB and brightens broadly and slightly to centre without apparent core or nucleus or zones. There is a 12th mag * off the halo to the NW by about 2'.



x185 27' TF

NGC 3952 (IC 2972) Galaxy *
RA: 11h 53m 40.5s Dec: -03 59' 44"
Mag: 13.5 (B) S.B.: 12.1 B-V: +0.38 Size: 1.5'x0.6'
Class: IBm: sp P.A.: 78 Inclination: --- R.V.: +1595 Source: RC3 *

IC 2969 Galaxy *
RA: 11h 52m 31.2s Dec: -03 52' 18"
Mag: 14.0 S.B.: --- B-V: --- Size: 1.2'x0.7'
Class: SB(r)bc? P.A.: 108 Inclination: --- R.V.: --- Source: RC3 *

This is a fairly obvious but lowish SB eg, overall brightness is okay. Seems to be elong in about PA 90 and is round basically to the S (maybe slightly E of S) from a mag 8 *. Spindle shape, 1.75 x 20" with a broad, slight brightening to the axis near centre but no real core etc.. 20' NW is IC 2969 which is just off round in PA 90 and about 50" diameter with a similar surface brightness and overall brightness.



x185 27' TF

NGC 3979 (IC 2976) Multi-Galaxy Sys *
RA: 11h 56m 01.1s Dec: -02 43' 11"
Mag: 13.7 S.B.: --- B-V: --- Size: 1.4'x1.1' Class: SB0^ pec:
P.A.: 69 Inclination: --- R.V.: --- Source: RC3 *

This eg is obvious as a small maybe 40" diameter round splodge of mist with a broad moderate central brightening with a faint stellaring at the centre. With direct vision it almost appears stellar and the stellaring in the centre is of similar brightness to a 15th mag * not far to the NNE.



x185 27' TF

NGC 4006 (IC 2983) Galaxy *
RA: 11h 58m 05.8s Dec: -02 07' 11"
Mag: 13.6 (P) S.B.: --- B-V: --- Size: 1.6'x1.1' Class: E pec:
P.A.: 20 Inclination: --- R.V.: --- Source: RC3

MCG +0-31-7 Galaxy *
RA: 11h 58m 23.9s Dec: -02 16' 35"
Mag: 13.8 (P) S.B.: --- B-V: --- Size: 1.5'x1.2' Class: SAB(rs)bc
P.A.: 119 Inclination: 1 R.V.: --- Source: RC3 *

MCG +0-31-10 Galaxy *
RA: 11h 58m 33.6s Dec: -02 08' 07"
Mag: 14.2 (P) S.B.: --- B-V: --- Size: 1.0'x0.5' Class: SB(r)0+:
P.A.: 19 Inclination: --- R.V.: --- Source: RC3 *

Of these three 006 is the most easily visible and is immediately obvious without searching. Pretty small and within a N-S snaking line of faint stars stretching from one side of the field to the other. Small, round or off round in PA 0, 30" diameter growing mod and broadly to the centre to a stellar nucleus. Now about 10 SE is MCG +0-31-7. It is a somewhat lower SB object nearly 1' diameter, round with a consistently LSB halo, diffuse edges and no core or nucleus.

Back to 006, 6' E is MCG +0-31-10 which is a very tiny spot of haze about 15" diameter, slightly brighter in the centre.



x185 27' TF

NGC 4012 Galaxy *
RA: 11h 58m 27.5s Dec: +10 01' 15"
Mag: 14.3 (P) S.B.: 15.6 B-V: --- Size: 1.9'x0.5' Class: Sb
P.A.: 153 Inclination: 6 R.V.: --- Source: RC3 *

This is a small elong eg pretty much in PA 150 and is almost pointed at by a lengthened 6' long I tri of mag 11 *s to the NW. Squashed oval of quite LSB with diffuse edges and a weak brightening to the centre, no apparent core, zones or nucleus.



x185 27' TF

NGC 4029 Galaxy *
RA: 12h 00m 03.1s Dec: +08 10' 54"
Mag: 14.3 (P) S.B.: --- B-V: --- Size: 1.2'x0.7' Class: Sb:
P.A.: 150 Inclination: 4 R.V.: +6144 Source: RC3 *

This is pretty much immediately visible though faint and small. The field is very blank There is a Tri + 1 of mag 13 & 14 *s to the N of the eg by a few arc-mins. Appears to be slightly elong, perhaps in PA 30 about 40" x 20" growing broadly and slightly to the centre without zones and no core/nucleus visible.

Pt 3 to follow ...
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  #3  
Old 09-04-2009, 12:01 AM
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ngcles
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Pt 3 cont ...

Pt 3 ...

x185 27' TF

NGC 4043 Galaxy *
RA: 12h 02m 22.9s Dec: +04 19' 48"
Mag: 14.6 (P) S.B.: --- B-V: --- Size: 0.6'x0.4'
Class: (R)SB(r)0^: P.A.: 135 Inclination: --- R.V.: +6462 Source: RC3 *

MCG +1-31-14 PGC 38052 Galaxy *
RA: 12h 02m 55.5s Dec: +04 14' 05"
Mag: 14.5 (P) S.B.: --- B-V: --- Size: 0.5'x0.5' Class: E
P.A.: --- Inclination: --- R.V.: --- Source: RC3 *

MCG +1-31-18 PGC 38122 Galaxy *
RA: 12h 03m 48.7s Dec: +04 13' 18"
Mag: 15.2 (P) S.B.: --- B-V: --- Size: 0.9'x0.3' Class: S
P.A.: 138 Inclination: 6 R.V.: --- Source: RC3 *

This little chap isn't that hard to see and is NW from a longish straggling line of mag 10th & 11th mag *s. Very small, only 30-odd arc-secs diameter and at first looks like a 15th mag * surrounded but a little fuzz. Grows mod to centre where there is a very faint stellaring or *ar nucleus.

MCG +1-31-14 and MCG +1-31-18 are SE by 10 and 20arc-mins respectively and are little more than 15" diameter scraps of mist, a little brighter in the centre.



x185 27' TF

NGC 4044 Galaxy *
RA: 12h 02m 29.5s Dec: -00 12' 44"
Mag: 14.0 (P) S.B.: --- B-V: --- Size: 1.1'x1.1'
Class: E+: P.A.: --- Inclination: --- R.V.: --- Source: RC3 *

Looks quite similar to -43 (previous observation). It is a very small eg about 20" diameter and at a lower power would be easy to mistake for a very faint *. Just a small spot of mist growing mod to centre where there is a 15.5 or 16th mag stellaring or stellar nucleus. Thinly populated field, no stars immediately associated.



x185 27' TF

NGC 4058 Galaxy *
RA: 12h 03m 49.1s Dec: +03 32' 54"
Mag: 14.1 (P) S.B.: --- B-V: --- Size: 1.2'x0.6' Class: SAB(r)0+:
P.A.: 165 Inclination: 5 R.V.: +5800 Source: RC3 *

Is another very small, almost stellar and pretty faint eg. Again in a fairly blank field, there are no *s of note nearby. Seems at best 15" diameter growing to a faint almost *ar sub-stellar nucleus.



x185 27' TF

NGC 4075 Galaxy *
RA: 12h 04m 37.8s Dec: +02 04' 22"
Mag: 14.5 (P) S.B.: --- B-V: --- Size: 1.2'x0.6' Class: SA(r)0+
P.A.: 128 Inclination: --- R.V.: +6530 Source: RC3 *

Another very tiny eg found to the NE of a very long rectangle of mag 10th - 12th *s in about PA 75. Almost *ar, 10-15" diameter and at first looks like a faint star with a bit of fog around it. Round and grows mod and evenly to centre where there is a whiff of a sub-stellar nucleus.



x185 27' TF

NGC 4078 Galaxy *
RA: 12h 04m 47.7s Dec: +10 35' 46"
Mag: 14.2 (P) S.B.: --- B-V: --- Size: 1.3'x0.4' Class: S0?
P.A.: 18 Inclination: 6 R.V.: +2529

NGC 4083 Galaxy *
RA: 12h 05m 14.1s Dec: +10 36' 47"
Mag: 15.3 S.B.: --- B-V: --- Size: 1.1'x0.5' Class: L
P.A.: 44 Inclination: --- R.V.: --- Source: PGC *

NGC 4082 Galaxy *
RA: 12h 05m 11.5s Dec: +10 40' 14"
Mag: 15.4 S.B.: --- B-V: --- Size: 1.1'x0.3' Class:
P.A.: 74 Inclination: --- R.V.: --- Source: PGC *

NGC 4067 Galaxy *
RA: 12h 04m 11.4s Dec: +10 51' 13"
Mag: 13.3 (P) S.B.: --- B-V: --- Size: 1.4'x1.0' Class: SA(s)b:
P.A.: 35 Inclination: 2 R.V.: +2403 Source: RC3 *

-87, -82 & -83 are in a small group while -87is one med-power field away to the NNW. -78 is in a pretty lonely field and is a pretty small and faint eg. Almost stellar, only 15" diameter, round and grows to a faint stellaring in he centre. There is a faint star just outside the halo to the W 7' E is -83 and -82 is NE by 9'. Both a very tiny <10" diameter spots of weak LSB mist hardly to be seen.

-67 is a small mod faint eg, round and about 40" diameter with a broad moderate azonal brightening . A couple of 13th mag *s to the E nearly point at it.



x185 27' TF

NGC 4176 Galaxy *
RA: 12h 12m 36.8s Dec: -09 09' 37"
Mag: 15.8 S.B.: --- B-V: --- Size: 0.7'x0.5' Class: Sb
P.A.: 55 Inclination: --- R.V.: --- Source: PGC *

This is a very, very small and faint eg with nothing in its immediate vicinity. A bunch of faint *s to the W 13 & 14 are about 4-5' away. Probably only 15" diameter rising evenly and moderately to the centre where there seems occasionally to be a threshold mag stellaring.



x186 27' TF

NGC 4191 Galaxy *
RA: 12h 13m 50.4s Dec: +07 12' 04"
Mag: 13.8 (P)S.B.: ---B-V: ---Size: 1.1'x0.7'Class: S0
P.A.: 5Inclination: 2R.V.: +2634 Source: RC3 *

NGC 4191 is a very small round eg but not too hard to see. Forms a RA Tri with 2 *s to the NE and NW mags 12 & 11, 4 & 2' distant respectively. Small spot 30 - 40" diameter, round, grows mod and evenly to centre with a possible small slightly brighter core-zone but no real nucleus.



x185 27' TF

NGC 4201 Galaxy *
RA: 12h 14m 41.7s Dec: -11 34' 59"
Mag: 14.4 S.B.: --- B-V: --- Size: 0.9'x0.8' Class: S0
P.A.: 80 Inclination: --- R.V.: --- Source: PGC *

In a field with just a few scattered *s this is a very tiny, almost *ar eg perhaps 15" diameter. Reasonable SB. Forms a small RA tri with a couple of 15th mag *s to the SE and S <1' away. Round and grows mod and evenly to the centre and seems at times to have a stellaring in the centre.



x185 27' TF

NGC 4240 (NGC 4243) Galaxy *
RA: 12h 17m 24.3s Dec: -09 57' 04"
Mag: 13.7 S.B.: --- B-V: --- Size: 1.2'x1.1' Class: E+:
P.A.: 119 Inclination: --- R.V.: --- Source: RC3

This small eg is a very compact but has reasonable SB hitched up to a 13th mag * just on the edge of the halo to the SW. Small, 1' diameter round, grows slowly at first but in the inner regions more strongly to compact core zone that does not seem to contain a real pip.


Best,

Les D
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  #4  
Old 09-04-2009, 12:25 AM
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Chippy (Nick)
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Thanks for sharing again Les. Very interesting about that short period star brightening. Sounds like it was an exceptional night on all accounts!
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Old 09-04-2009, 09:31 AM
Coen
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Thanks for sharing the report on what sounds like a fantastic night.

Will be curious to see what theoretical explanations might come to explain the transient phenomenon that you saw.

Given the number of things that you covered in an evening and the volume of notes you took for each object there must be a technique you have honed over your time at the eyepiece. Have you ever written up your technique or shared it? I'd be most curious and grateful on any tips and pointers to keeping records to recall the enjoyment of the time at the eyepiece.
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Old 10-04-2009, 08:21 AM
Rob_K
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Excellent report again Les, very thorough and lots of interest there. Titan as a reddish fawn disc has me drooling, lucky if I see a pinprick (yes, I know the solution! ).
Cheers -
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Old 10-04-2009, 09:56 AM
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ngcles
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Appreciate the comments

Hi All,

Quote:
Originally Posted by Coen View Post
Will be curious to see what theoretical explanations might come to explain the transient phenomenon that you saw.

Given the number of things that you covered in an evening and the volume of notes you took for each object there must be a technique you have honed over your time at the eyepiece. Have you ever written up your technique or shared it? I'd be most curious and grateful on any tips and pointers to keeping records to recall the enjoyment of the time at the eyepiece.
Yep, I do find that keeping a record of what is seen is very useful for comparing notes with other observers, for your own satisfaction and there are one or two other uses as well ...

I don't know there is anything special about it to be called a technique -- it's just a way to keep notes so that they're all as consistent as possible and so that the log doesn't end up simply looking like this:

47Tucanae: Beautiful
M42: Very pretty
NGC 5128: Nice big galaxy.

There's nothing wrong with using superlatives and comparatives, it just that when the log is getting big and that's all it says, then it's not much use if everything is described simply as "pretty".

First off, for the purposes of the way I do it it is important to know the size of the field produced by the eyepiece. It's impossible to estimate sizes distances etc etc without knowing that. To estimate sizes, big things are easy and small things (like most of this lot) is harder and the smaller they are the more likely it is to be a best guesstimate. In my case the 12mm TII Nagler field with this 'scope is 27 arc-mins diameter. Half a field is [I]about[I]13 arc-mins, 1/4 is 7, 10th is about 3 etc etc -- so that is how I go on size. As for even smaller things, if there are a couple of faint stars in the field that are apparently separated by the same distance, or twice the distance, or half etc etc as the diameter of the object in question, then I use the planetarium software to give me that distance between those stars and use that accordingly. That is done in the field -- the heavily-reddened laptop is always running and showing the field I'm looking at usually with a DSS pic overlay from Realsky.

If it is elongated I make an estimate of the length of the long axis first and then compare the long to the short -- is it 3/4, 1/2, 1/4, 1/10th etc etc.

As to Position Angle, this is nowadays much harder with a Dobsonian/Newtonian than my old Newtonians which were mounted on GEM. Back then I'd just use the Dec control to move the 'scope exactly North-South. Not possible now. I used to be able to get PA down to about 10 deg but with the alt-axis motions of the dobsonian mount -- can't really do unless it's pointing exactly east or north etc etc. More often than not, what I do now is try to see a field star that the galaxy points at or nearly at and then find that in the image and work it out roughly from that.

As to all the other descriptors, I've copied and adapted those from the set of descriptors used by Skiff & Lughinbul in their observing guide -- which I personally think is the best around. The text in that book can be a bit dry at times (as is reading some of my observations) but it is very very functional.

As I observe I ask these sorts of questions: Does it brighten toward the centre or the axis. To what degree? What is the gradient etc etc and that ends up reading something like:

"It is pretty small, 40 - 50" diameter, round reasonable SB and brightens broadly and slightly to centre without apparent core or nucleus or zones."

If there are "zones" -- ie a sudden jump in brightness, I note them likewise the nature of any nucleus. "Stellaring" is a term I've adopted form Skiff & Lughinbul as it describes an almost stellar or stellar like type spot that is not a definite star or stellar nucleus.

Note any nearby stars, their brightness (guesstimate) and positions and any unusual characteristics of the field -- and that's about it really. Its all recorded on a small solid-state dictaphone. I start every entry with the ID of the object and the eyepiece used and later on at home it is digested down and typed up in my log which at present is kept with a data-base software "Deepsky".

The most important things I forgot to mention is this -- when I go to an object to observe it and this is in particular with faint objects like most of these galaxies in this report I first look at the map/pic on the laptop and try to see a star-pattern somewhere that will act as a guide to seeing it (assuming it isn't immediately visible). If it's really faint, this can mean one or two trips back to the laptop. After I've located it successfully and am as certain as to ID as I can be, I spend 5-odd minutes just looking before I start recording -- which usually takes about 90-secs-odd to record. I have ___ to ___ speak ___ slowly ___ because ___ I ___ don't ___ type ___ too ___ fast.

That's about it. I dunno whether you'd call it a technique its just what I do and in this way I can get through maybe 8-10 single objects per hour or if there are clusters (groups etc) of galaxies somewhat more -- but they slow you down working out how far this is from that and in what direction etc.

If you like it, by al means adopt it. If you lke some, adopt some or whatever or coe up with your own one that suits your needs. IN the end it's just a method and a set of common descriptors and there's no copyright or anything like that.

A couple of other thngs on these descriptors:

Weak, Slight, Moderate and Strong -- all describe the extent of a brightening trend.

Zones are sudden (in context) changes in a brightening gradient.

Broad (up-turned bowl shape), Even (conical) and Sharp describe the shape of any gradient (shape -- kinda) of brightening.

Words like, Ephemeral, Gossamer, Milky, Diffuse, Cottony, Hazy, Grainy describe apparent texture.

Combine something like slight and broad, and you get a picture of how much it brightens to centre and what the grade looks like. etc etc


Hope that is some help.


Best,

Les D

Last edited by ngcles; 10-04-2009 at 10:31 AM.
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Old 10-04-2009, 09:39 PM
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Excellent description of your techniques Les. Thanks to Coen for asking!
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Old 13-04-2009, 09:12 PM
Coen
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Thanks very much!
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