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Old 19-05-2012, 08:25 AM
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madbadgalaxyman (Robert)
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Join Date: Mar 2011
Location: Brisbane
Posts: 936
Quote:
Originally Posted by boomstix View Post

Last on the list for the night was NGC5128 which was the most elusive thing to find. It was really hard as the light pollution really drowned out most of the stars I was trying to use as guides to find it. After about half an hour of scanning the general area it was in a faint smudge moved across my view. I centred in on
It has always been hard for amateur astronomers to make their way to NGC5128 using stars on the way, and I have always found that a magn. 8.5 limit Star Atlas shows way too few stars to enable a reliable acquisition of the object. I use the software star charts called Guide V.8 and Megastar, which show a lot more stars (plus over 100,000 deep sky objects). Guide is cheaper, but much less user friendly, however it has similar (or better) capabilities than Megastar.
Even with a magn. 12 or 13 limit, there are few stars on the way to N5128.

We have had very poor conditions for viewing deep sky objects in Brisbane, for quite some time.
I am unsure of the explanation for this, but it reminds me of the bad effects of the very high altitude aerosols from the 1991 eruption of the Mt Pinatubo volcano, which were particularly pronounced from my observing site near Darwin; it was virtually a waste of time to view all but the most prominent deep sky objects for at least 1-and-a-half years.

cheers, Robert

A third option for getting more stars to use for a difficult Star Hop to an object is to use the virtual sky at the Wikisky website, but a magn. 20 limit might be "too much of a good thing"

Oh, and Matt, in my view, the big jump in deep sky performance is between an 8 inch and a 10 inch. A ten inch has 1.56 times the light gathering power of an 8 inch. But a 12 inch has about 1.4 times the light gathering power of a 10 inch. I would certainly recommend an 8 inch for most adult beginners, but even the smallest 10 inch is a large and and unwieldy object, and 12s are invariably BIG telescopes.
(consider that, given the same design and the same materials, a 12 inch is 70 percent heavier than a 10 inch!!! No wonder a lot of 12 inch telescopes end up as infrequently used "white elephants")

Last edited by madbadgalaxyman; 19-05-2012 at 08:39 AM. Reason: more
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