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Old 03-04-2011, 03:20 PM
Rob_K
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LMC small-scope report for Paddy

Well, finally got some free time to write up my report from Snake Valley! Hope it makes sense - it was a while ago and I had to decipher & interpret my rough field notes taken at the time. For anyone who wishes to read the report, this chart from Patrick's web-site will help:
http://www.cloudsofmagellan.net.au/lmcinseta.htm

Observing the LMC with a 4.5" telescope.

Observer: Rob Kaufman
Date/time: 9pm-midnight (various), 6 March 2011 (UT+11).
Location: Snake Valley, Victoria, Australia. 37.6S, 143.6E
Telescope: Tasco 4.5" f8 reflector (114x900mm)
Eyepiece: 21mm Celestron X-Cel (43x)
Transparency: 7/10
Seeing: 6-7/10

Session Notes: This observing session was planned as a fair test of what Large Magellanic Cloud objects could be viewed through a small telescope under good conditions, using the Clouds of Magellan charts. Only a small area around NGC 2070 Tarantula Nebula was chosen. This area has an abundance of catalogued objects of varying type, visual magnitude and size. Sky conditions were good but not perfect, thanks to an on-going La Nina weather pattern which has placed so much moisture in the atmosphere over SE Australia. Ideal eye adaptation was not gained over the first part of the session, working backwards and forwards from eyepiece to the charts under red light illumination. Later, some of the fainter objects were revisited without recourse to charts, and considerably more detail gained. All of the objects described below fitted in little more than one field of view at 43x. After the session, I was able to view some of the small objects at higher power through a 12" SDM telescope under the same sky conditions, and occasional reference is made to these observations.

General Notes: Observing faint deep sky objects in a small aperture telescope requires three things in order of importance they are DARK sky, good eye adaptation and for objects with very faint fine detail, good seeing. Aperture limits you to low powers in my case 43x with a 21mm eyepiece suits for most deep sky viewing. Dont listen to people who tell you that increased power gives increased contrast which can make faint things easier to see. Firstly, you should be observing from a dark site so there is little contrast to be gained, and secondly while it might apply to telescopes with aperture to burn, increasing power on faint objects through a small telescope is generally like switching the lights out! You just run out of light.

OBSERVATIONS:
NGC 2093 open cluster: At first, nothing there, then a tiny faint glow less than an arcminute in diameter became apparent in averted vision. Two very faint stars were visible perhaps an arcminute apart, one associated with the glow and one to the west. Later with better eye adaptation the cluster showed a tight graininess in the centre, only in averted vision and very faint. Fairly settled seeing helped I hadnt seen this from home in darker skies, but chronic poor seeing.
HS397: Large roughly oval glow about 5 arcminutes long, with a few faint stars.
NGC 2108 open cluster: Tiny faint glow in averted vision, no stars resolved.
NGC 2100 open cluster: Lovely object, like a small centrally-condensed globular cluster about 2 or three arcminutes in diameter. Quite bright, easily held in direct vision. No stars resolved at first, but later with better eye adaptation the cluster showed definite graininess. Beautiful afterwards in 12" reflector, with many stars clearly resolved.
NGC 2092 open cluster: As with 2093, nothing showed at first, then a tiny faint glow less than an arcminute in diameter became apparent in averted vision. Later with better eye adaptation the centre of the cluster showed a tight graininess, at the very limit of averted vision. Viewed through the 12" at higher powers afterwards (c 100x ?), this was a nice but small object with several stars resolved.
NGC2070 Tarantula Nebula: Didnt spend a long time on this object, but it is one of the wonders of the sky even in a small scope at low power. Bright interwoven streamers from a brighter core, about 15 arcminutes in diameter. Not the best view Ive had of it.
NGC2069 nebula: Easily visible as a reasonably bright tail-like object streaming northwards from the Tarantula Nebula in a slight arc.
NGC 2060 open cluster/nebula: Just appeared as a small tuft of nebulosity on the south-west side of the Tarantula Nebula.
SL607 open cluster: As with the similar nearby clusters, nothing showed at first, then a tiny faint glow less than an arcminute in diameter became apparent in averted vision. No resolution or graininess, even with better eye adaptation.
SL585 open cluster: As above, but the faintest tight graininess visible in averted vision with better eye adaptation.
NGC2042 open cluster: Appeared as a large very faint glow almost 10 arcminutes in length. A faint wide arc of stars could just be seen in averted vision, giving the cluster a slight boomerang shape.
NGC 2044 open cluster/LH90: A broad patch of mottled dim nebulosity perhaps 10-15 arcminutes long appears here. Few stars of the cluster 2044 are visible the area of the cluster is dominated by a line of three faint stars. Interesting that the bright star shown on the chart could not be seen.
NGC 2050 open cluster/LH93: Nothing much showing other than a small triangle of faint stars.
NGC 2081 open cluster/nebula: This object was rewarding with a little patience. Not much seen at first except a dim semicircle of nebulosity in averted vision. With more intent staring and averted vision, the faintest glow of a complementary arc of nebulosity came into view to the west, not quite linking to form an oval shape. A patch of tiny stars was visible within the arcs, but only in averted vision. The stars were against a black background and as opposed to the other clusters viewed, the stars were tiny well-defined pinpricks. 2081 appeared to be 7-8 arcminutes long and about 5 arcminutes wide.
NGC 2074 nebula: Strong patch of nebulosity maybe 3 arcminutes in diameter. No real detail visible.
NGC 2055 open cluster/LH94: A faint tiny background glow about an arcminute in diameter in averted vision. Two faint stars visible within the cluster.
NGC2048 open cluster/LH87: Very faint tiny background glow in averted vision, did not resolve at all.
NGC 2052 nebula: Very difficult, but eventually got a tiny extremely faint glow in averted vision with better eye adaptation. The view was not that much different to a number of the smaller open clusters near the Tarantula Nebula, only fainter.
NGC 2077/2078/2079/2080/2083/2084/2085/2086/IC2145 nebulae: Effectively one object at this scale, and shows as a slightly mottled bright patch of nebulosity 3 or 4 arcminutes in diameter, strongest at the south-east end (2084). Two brighter stars on the west side marked the positions of 2078/2079. The gap between 2083 and 2084 was not visible.

Cheers -
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Old 03-04-2011, 03:42 PM
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Paddy (Patrick)
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What a stunning report, Rob. A fine example of you skills at observing and recording what you've observed and a great example of what can be seen with a very modest telescope and some careful attention!

Many thanks!
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Old 04-04-2011, 08:23 PM
Rob_K
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Thanks Patrick. Would have liked to have done more, but.... "short attention span, easily distracted". Great exercise though, especially on so many tiny objects.

Cheers -
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Old 05-04-2011, 06:43 AM
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see

Proves you can see quite a lot with a small aperture telescope.
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Old 05-04-2011, 11:12 AM
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Fabulous report and an enjoyable read.
Many thanks for sharing it with us Rob.
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Old 05-04-2011, 12:44 PM
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Octane (Humayun)
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That was a great report, Rob. Very interesting! Wish I had the aperture to image those barely-resolvable objects.

Well done!

H
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Old 09-04-2011, 06:44 PM
Rob_K
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Thanks all. I'm away in far west NSW - brilliant skies for the last week and I don't have my scope with me...

Cheers -
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Old 25-04-2011, 04:42 PM
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orestis
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Sorry for not seeing this earlier.

Great report Rob,Great stuff.

Shows what small scopes are capable under dark skies.

Thanks for posting
cheers orestis
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