fivemack: (iguana)
[personal profile] fivemack
This is the twenty-inch Newtonian reflector at the Centre for Observational Astronomy in the Algarve, where I have just spent five nights

big-scope

And this is roughly what you get if you point it into the middle of the Virgo galaxy cluster, attach my nice camera, leave the shutter open for 90 seconds at ISO1600, and tidy up a bit in Photoshop afterwards.

galaxies

I think there are six and a half galaxies visible here; M84 and M86 are the big ellipticals top and bottom respectively, NGC4387 is the little one in the middle, NGC4388 is the interestingly-shaped one on the right, NGC4402 is the dim fuzzy one on the bottom left, IC3303 is the teeny faint one you get to if you start at M86, go to 4387 and keep going, NGC4413 is the half-cut-off one right at the bottom on the right. I'm not at all sure what the name of the tiny companion galaxy about a centimetre at clock-7:30 from M86 is.

Date: 2015-05-28 04:47 am (UTC)
From: (Anonymous)
well done!

Date: 2015-05-31 04:33 am (UTC)
From: [identity profile] tau-iota-mu-c.livejournal.com
There's more than 6½ there. Lots more fuzzy nonstarlike blobs quite a bit above the noise floor.

Date: 2015-05-31 09:54 am (UTC)
From: [identity profile] fivemack.livejournal.com
With the slight differential focus across the field, and auto-guiding against a strong wind giving me stars with an FWHM of about five arc-seconds, I'm not sure I can confidently tell a fuzzy non-starlike blob from a fuzzy star.

I did a plate solution with http://nova.astrometry.net/user_images/687126#annotated to get to six and a half; I don't know of an on-line tool where I can say '36x24 arc-minute image around 12 25 39 +12 49 12, east is up, superimpose the whole PGC catalogue'; if I ask SIMBAD for ten arc-minute radius around NGC4387 http://simbad.u-strasbg.fr/simbad/sim-plot?ident=NGC++4387&coo=12+25+41.715%2B12+48+37.29&radius.unit=arcmin&x=69&y=58&radius=10 it takes several minutes to return me a tiny image which could well be the Wikipedia title image for 'source confusion'.

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