Just thought to say hi in here.. so.. hi
Just thought to say hi in here.. so.. hi
Wow! Thanks for joining and welcome to DSF, Hanny!
Clear skies,
Alvin
#26
22" f/4 reflector plus assorted smaller and larger telescopes, but listing the one I use most.
faintfuzzies.com
Hello Hanny.
Hiya and thanks for the welcome
From the details Alvin has brought out about the red-shift to about 530nm it would seem the Johnson/Cousins V filter may offer improved contrast for this object over the Sloan G given a large scope. The Sloan G is 150nm wide at that point with near 100% transmittance so it wins with transmitted light (important here of course). The Astrodon version of the V filter is by far much narrower in the 530 area and is tapering off in this range. The V is about 50nm wide but sloping off from it's peak of 94% at 520nm, 91% at 530nm, 86% at 540nm, 83% at 550nm where Sloan G drops like a rock. At 10% transmission the V is 140nm wide which approaches the Sloan G bandwidth of 50nm but is well down.
Marko
Last edited by Marko; May 6th, 2012 at 06:45 PM.
Let me roam the deep skies and I'll be content.
Mark Johnston
18" StarMaster f/3.7
12" Meade LightBridge f/5
Jerry and Jimi, I tried for Hanny's at the 2011 TSP with my 32"f4 with no filter at 361X, about 2345 CDT. It was only 22 degrees above the horizon, and conditions were obviously not ideal. This was a negative observation, and I would like to try for it higher in the sky. The Astrodon filter sounds like it would help quite a bit. I heard of several people at the 2012 TSP that were able to view it in Larry Mitchell's 36".
Dave Tosteson
Dave,
That is correct. Jimi and I were among that group who observed it with Larry's 36". It was tough, but there. Also it was pretty high up as well in April versus June in TSP 2011.
Clear skies,
Alvin
#26
22" f/4 reflector plus assorted smaller and larger telescopes, but listing the one I use most.
faintfuzzies.com
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