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Equipment Discussions / Re: acquired a celestron ci700 (losmandy g11)
« Last post by John Pierce on March 23, 2017, 04:55:39 PM »
hmmm, said coulter has a 65mm (minor axis) secondary, so rough calculations suggest that with a 12" OD tube, plus focuser minimum height plus the 44mm flange distance of a EOS DSLR, I'd only get a 16mm diameter image circle before the image starts to darken significantly.    not good enough for an APS-C DSLR!! (which has a 28mm or so image circle)
Equipment Discussions / acquired a celestron ci700 (losmandy g11)
« Last post by John Pierce on March 23, 2017, 02:04:02 PM »
so I just acquired a rather nice CI700 equatorial mount, this was a celestron branded 'cheapened' version of the Losmandy G11...   its a beast.  has alt and dec slo-mo motors but no goto.

I initially was thinking of using it for unguided piggyback as I don't really have a suitable scope for it, but now I'm wondering if I couldn't rebuild my Coulter 10" F/4.5 ... use one of Mark's Astrogoods alloy tubes, a better focuser than I now have, shorten up the tube enough that I can achieve focus with my DSLR (the secondary on the coulter is huge).  I have already replaced the coulter's primary mirror cell with one of Mark's creations, and the secondary spider with a curved vane spider from 1800destiny.

am I nuts for thinking this is a good idea?   the mount is rated for 60 lbs of instruments, 100 lbs total.   Celestron sold it with  C11 and C14 telescopes on it :-O

TAC Visual / Mars MRO Video
« Last post by pnatscher on March 21, 2017, 06:57:48 PM »
An inspiring video from the Mars Reconnaissance Orbiter to enjoy during our rainy weather.  View full screen!
TAC Visual / Re: Colliding Galaxies
« Last post by Marko on March 17, 2017, 04:33:34 PM »
Way to go Mr Steve!     For sure a keeper of a S&T issue.

TAC Visual / Colliding Galaxies
« Last post by sgottlieb on March 17, 2017, 02:39:48 PM »
I wanted to mention I have a featured observing article titled "Galaxies in Collision" in the May issue of Sky & Tel, which should be out shortly (the digital version is already available).  It includes a number of interacting Arp pairs including the Antennae (cover photo) and other interesting duos such as the Mice, the Tadpole, the Heron, the Grasshopper and more.  Some of these are fairly well known and others are pretty obscure.  If anyone would like more "info" on the article, let me know.

Joe, my anecdotal experiences may not be the best predictor, but here's been my experiences on two trips that time of year --

In mid-October '15, I observed at the Markdale site, along with John Hoey and Kemer Thomson.  I think the forecast was looking pretty bleak the day I flew to Sydney, so I was surprised the first half of the first night was clear (perhaps 4 hours).  The next day (Sunday) it rained all night, so not a great start at this point.  But then we had 5 consecutive all-nighters with very little or cloud-free conditions.  So, I ended the week exhausted from the number of hours of observing (6 out of 7 nights).  I check my notes again and SQM readings were consistently above 21.8 with several readings between 21.9-22.0.  I believe the star party last October/November had similar luck with the weather.  Locals Dennis Beckley and Bob Douglas attended, though you probably would have to contact them directly for their experiences.

In early November 2010 I observed at Coonabarabran, which is further from Sydney (perhaps a 6 hour drive).  The weather prospects looked dismal the few weeks leading up to the star party with consistently cloudy conditions and rain throughout New South Wales.  But although there were clouds during the daytime, it cleared by sunset on the first 4 days of the star party and I got in quite a bit of observing under impressive skies (SQM readings generally 21.85-21.89).   But we had clouds/rain for the last 3 nights, so we ended up with 4 out of 7 clear nights.

So, yeah, there is a risk with clouds/rains but I've rarely (if ever) returned from a trip to Australia bummed out by the weather (say with over half the observing time missed due to weather).  Conditions are drier further in the interior or perhaps on the west coast, but then you're really on your own in terms of planning a trip, and would have to lug along your own equipment.

Also, if you haven't been to southern hemisphere before and are only planning a single trip, then I would recommend going to the March/April star party as you get the full Milky Way overhead experience with lots of great nebulae/clusters that you haven't seen before.
what is the weather like there in october?? Looking at the Wiki page for sydney I see 11.1 rainy days in October.

Given how this rainy season has been here in the bay area...I'd hate if most of my days there were underneath clouds
I'll have to check it out.  I'm not sure how I got hooked on it, but I've actually watched a Australian melodrama (at least 3 seasons) that takes place in the 1950's called "A Place Called Home".  Full of stereotypes, prejudice and an over the top villain.  Nothing to do with astronomy, though.

By the way, the October event has been moved to a country sheep farm (Markdale) about 3 ½ hours west of Sydney.  Beautiful location that I observed at a year and half back.  SQM readings consistently above 21.8!  I know there's still openings if anyone has had a desire to observe in the southern hemisphere.

I posted this last year, I'll post it again,

stumbled onto this amusing Australian tv series, apparently it ran across Australia earlier this year.

the whole thing is on youtube,

Under the Milky Way is a 6 part (28 min each) Australian TV comedy/drama about an astronomical observatory in Coonabarabran NSW, thats being shut down because a fancy new larger observatory has opened nearby.     The whole thing was filmed on location at Siding Springs and Coonabarabran.
TAC Visual / Re: Moon and Aldebaran
« Last post by smigol on March 14, 2017, 09:28:39 AM »
Nice report.  Reminded me of the time I saw the moon occult the Pleiades back in 1992.
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