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A couple from Sunday night

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Big Dipper
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« on: March 03, 2009, 07:32:11 am »

Finally got around to butchering processing a couple of images from Sunday night folks. The first was taken with a 135mm lens set at f4, mounted on my AstroTrac and my Kenko 'Halpha' filter, a combination of four, 3-minute each, light frames

The view shows two bright stars (Mu Geminorum to the left & Eta Geminorum to the right). The open cluster M35 is uppermost with IC443 between the two bright stars & the often overlooked NGC2174 (in Orion) nearest to the bottom (often described as a mini Rosette nebula).





The second is a crop taken on Sunday night with a cheap Paragon 500mm f8 lens mounted on my AstroTrac and a combination of four, two minute each, exposures using a new set up I was experimenting with which allows me to mount a 6X30 finderscope and camera at the same time. There were some flexure problems which I have yet to perfect - but this set up certainly made locating & framing M13 a breeze!

The lens is a cheap one so the resolution wasn't as good as, say, a Takahashi.   Grin I therefore sharpened it a bit in PS.

No filter was used - not did I take any darks or flats.
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Andy

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brianb
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« Reply #1 on: March 03, 2009, 09:48:15 am »

Love the "twins foot"!

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The second is a crop taken on Sunday night with a cheap Paragon 500mm f8 lens mounted on my AstroTrac and a combination of four, two minute each, exposures using a new set up I was experimenting with which allows me to mount a 6X30 finderscope and camera at the same time. There were some flexure problems which I have yet to perfect - but this set up certainly made locating & framing M13 a breeze!
Yes, there is some "streaking" evident. However it should be fixable, I've managed 2 min subs with a 300mm f/2.8 on my Astrotrac, I guess my setup is much heavier than yours....

As for the finderscope, good idea; I got a cheap 8x21 monocular (ugh) and glued it to the top of a "dead" miniature flash gun. Stuff it in the hotshoe, problem solved! The alignment is "good enough" rather than great, and more light grasp would (as usual) be useful, but the idea seems to be OK. Actually the camera viewfinder shows quite a lot especially with a 300mm f/2.8 providing a narrow band filter isn't used.... but with a deep red filter it's hard to see anything through the VF. Accurate focusing is something of an art rather than a science as well, especially since my 300mm f/2.8 "drifts" with temperature changes.

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Big Dipper
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« Reply #2 on: March 03, 2009, 01:53:36 pm »

Appreciate the feedback Brian and yes, my set up is a pretty lightweight affair. It comprises an over-20-year-old Slik 88 tripod (a very good model in the mid 1980's - or so I was told). Next comes the Manfrotto 410 with its micro adjustments for polar alignment, followed by the AT & then the Slick pan head (which I much prefer to using a ball head). The pan head allows for coarse adjustments & attached to it I have an Orion Precision Slow Motion Adaptor which I could have used without the Slick pan head, if only the Slow Motion adapter also allowed for coarse azimuth adjustments to be made. The adapter then had an additional flash bracket attached for mounting the camera & finderscope, side by side.

Plenty of room for flexure problems in that little lot - so this new set up for relatively long focal length (lens-wise) will probably need refining/trimming somehow.

Yes, you can see quite a bit through the camera viewfinder with dark adapted eyes. I tend to get the intended target into view before finally screwing on the Kenko filter (mine has a 52mm thread for attaching to camera lenses).
« Last Edit: March 03, 2009, 01:56:18 pm by Big Dipper » Report Spam   Logged

Remember:- If all else fails, read the Instruction Manual! Grin
 


Andy


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