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Jeff Young
Post Laureate
   
Reged: 08/04/05
Posts: 4330
Loc: Ireland
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A bunch of Arps and an Abell
10/12/09 06:32 PM
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I've gotten a little behind in logging my observations, so here's 3 reports in a single thread.
Quote:
Arp29 NGC6946 8/24/2009 22:16 UT; Pickering 7, NELM 5.5, SQM 20.5 400mm Mak-Cass @ 150x
Moderately bright, large circular patch with just the vaguest hint of condensation to the center. Somewhat improved surface brightness at 110X, where the location of the core is also easier to pin down. Hints of one heavier arm to the NE, and a less dense but larger arm to the NW.
375X reveals a couple more foreground stars superimposed, but no clumping or other features in the arms.

Quote:
Arp38 NGC6412 8/24/2009 23:46 UT; Pickering 7, NELM 5.5, SQM 20.5 400mm Mak-Cass @ 225x
Pretty much invisible at 150X but a bit of motion brings it out. Very poor condensation with a suggestion of a core perhaps 20% of the time in averted.
(Interestingly, both the GSC and the DSS image put the core brighter than some of the field stars, but I guess the contrast loss with the galaxy around it is significant. Transparency also seems to have been deteriorating by this time as I failed to record many stars in the high 13's / low 14's in the sketch.)

Quote:
Arp81 NGC6621 8/25/2009 00:11 UT; Pickering 7, NELM 5.5, SQM 20.5 400mm Mak-Cass @ 225x
Another one barely visible under these conditions. Two poor condensations in an elongated (NNW-SSE) smudge.
Quote:
Arp30 NGC6365A 8/25/2009 00:21 UT; Pickering 7, NELM 5.5, SQM 20.5 400mm Mak-Cass
Suspected a couple of times to the NE border of a kite asterism, but nothing definite. Transparency has gone to hell, though, struggling to even make NELM 5.
[Turns out to be a string of mV14+ field stars. Galaxies off other side of kite.]
With the transparency continuing to worsen I called it a night.
A few days later conditions were quite favorable so I thought I'd give a few Abell PNs a go:
Quote:
Abell78 PK 081-14.1 8/28/2009 22:31 UT; Pickering 7, NELM 6, SQM 20.8 400mm Mak-Cass
Not seen.
Quote:
Abell81 PK 117+18.1 8/28/2009 23:11 UT; Pickering 7, NELM 6, SQM 20.8 400mm Mak-Cass @ 150x, OIII
Averted vision at 335X and 150X, but difficult. Easy averted and moderately-difficult direct vision when the OIII is added at 150X. Also direct at 235X with UHC (OIII slightly overpowers). 335X gets rid of distracting field star, but even UHC overpowers a 1.2mm exit pupil. 450X not really any help.
Unfiltered views show two involved stars, one right on the edge and one a bit farther off. Unfiltered also looks a bit flared, but I think that's just a contrast effect with the two close field stars. Shape very round filtered, with suggestions of annularity. The minima also pops out from time to time unfiltered at high magnification (335X and 450X).

Quote:
Abell68 PK 060-04.1 8/28/2009 23:40 UT; Pickering 7, NELM 6, SQM 20.8 400mm Mak-Cass
Not seen.
Quote:
Abell46 PK 055+16.1 8/28/2009 23:55 UT; Pickering 7, NELM 6, SQM 20.8 400mm Mak-Cass
Not seen.
Well, that wasn't going terribly well, so I went back to the Arp I failed to find the first night:
Quote:
Arp30 NGC6365A 8/29/2009 00:06 UT; Pickering 7, NELM 6, SQM 20.8 400mm Mak-Cass
Did a quick and dirty field sketch of the SW side of the kite. I included 4 very dim field stars, one of which appeared somewhat elongated.
[Field stars around mV14; elongated one turns out to be a mV13.5 double star. Galaxies in between 3 of the 4 sketched. I'd say this one's out of reach.]
No dice there either, but still, the Arps are considerably easier than those dang Abells.
Quote:
Arp124 MCG+10-25-003 8/29/2009 00:16 UT; Pickering 7, NELM 6, SQM 20.8 400mm Mak-Cass @ 225x
Easy averted vision at 150X. 235X and 335X much the same, with 235X being just a little bit easier. 4:1 elongation NE-SW; limited condensation to center but no core visible.
Didn't get the companion, but a couple of field stars in the sketch are only marginally brighter. Still, conditions were quite good, suggesting that barring an exceptional night (and a bit more altitude), it's going to be out of reach.

Quote:
Arp330 MCG+09-27-095 8/29/2009 00:30 UT; Pickering 7, NELM 6, SQM 20.8 400mm Mak-Cass
Some of these were suspected, but never nailed down. I suspect they could be with an image/chart at the scope.
Quote:
NGC6951 8/29/2009 00:45 UT; Pickering 7, NELM 6, SQM 20.8 400mm Mak-Cass @ 150x
Well-condensed direct-vision bar running E-W, with nearly stellar nucleus. Much greater extent in averted, also elongated E-W, going out to bright foreground star to E and an equal distance to W. 150X lacks scale, but galaxy brighter than at higher mags.
I've got a few more from last night that I'll post later.
Cheers, -- Jeff.
-------------------- Nikon 18x70s / UA Millennium Colorado:
Solarscope SF70 / TV Pronto / AP400QMD Coronado SolarMax40 DS / Bogen 055+3130
APM MC1610 / Tak FC-125 / AP1200GTO Tak Mewlon 250 / AP600EGTO
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