From: "cosmicrock2001" <ursamajor_1@mac.com>
Date: September 30, 2009 11:29:01 AM MDT
To: Astro_IIDC@yahoogroups.com
Subject: Re: [IOTAoccultations] Video Recording planning and preprations for the LCROSS impact plume
A better source of info (answers all your questions) for amateurs planning to observe/image the event is this webpage set up for amateurs:
http://lcross.arc.nasa.gov/observation/amateur.htm
I hope to use my 12.5" f/6 newt and DBK camera/AstroIIDC. As noted on the webpage the plume is expected to be roughly half the size of Saturn. It'll be tough if the seeing is bad (as usually is at my foothills location) but doable. I like to think of it as capturing an occultation of Mars on the limb, so we oughta see something!
Ron
--- In Astro_IIDC@yahoogroups.com, Milton Aupperle <milton@...> wrote:
Hi Terrence;
See:
http://lcross.arc.nasa.gov/observation.htm
and more recently:
http://www.nasa.gov/mission_pages/LCROSS/main/rss_feed_collection_archive_1.html
for details. They changed which crater they will hit (switching to
Cabeus proper isntead of Cabeus A) on September 28 too.
As to picking anything, It's pretty doubtful.
The previous impact event of kaguya was only captured using the Anglo-
Australian monster big professional scopes (I think it's 3.92 meter
aperture) and completely in the narrowband infrared with 1 second
exposures and got 2 frames. Also that impact was in the dark
terminator and plume showed up against the black shadowed space.
http://www.space.com/news/090610-kaguya-moon-impact.html
http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=44977
This time around it's not clear if we will see anything above the
horizon at all. That area is fully illuminated and a long way from the
east terminator. To separate from the lunar surface, the it's going to
have to be kilometers high up plume or it won't make it over the rim.
With my C8 at 4 meter focal length, 1 kilometer is about 2 pixels on
my Flea or Grasshopper cameras.
I put together an image of what the moon will look like from Calgary
at 5:30 am MST October 9th :
http://groups.yahoo.com/group/Astro_IIDC/files/Other/Cabeus_Impact_MJA.jpg
and labelled some of the craters, including Cabeus. For me the moon
will be at zenith then and about 64° above the horizon, so it's as
good as it gets for observing. I also put up FOV indicators to give
you some idea of scale too. Those pink boxes are what I get with the
Flea (640x480 7.4 micron pixels) and Grasshopper (1384x1036 6.7 micron
pixels) in arc minutes using a 2x barlow on my C8 (effectively 4,000
mm focal length).
To even begin to resolve it, your going to need a 2x to 5x barlow, and
that means longer exposures which increase the square of the
magnification. So if you shoot with a 2x barlow, then you need 4x the
exposure time and with a 5x barlow, you need 25 times as much exposure
time.
HTH..
Milton J. Aupperle
President
ASC - Aupperle Services and Contracting
Mac Software (Drivers, Components and Application) Specialist
#1106 - 428 Chaparral Ravine View SE.
Calgary Alberta T2X 0A5
1-(403)-453-1624
milton@...
www.outcastsoft.com
On 28-Sep-09, at 8:04 PM, Terrence Redding wrote:
Tom, I am glad you have started this thread. I too plan to record
this event and have the same concerns.
What would be the best filter to use from the east coast of the USA?
How aperture dependent is this event?
I assume most of us will attempt at 30 FPS. But would 60 or 120 FPS
be better? I have a firewire camera capable of 120 FPS recording
direct to disk.
What would the optimum setup be for a 3", 4", 5", 6", or larger
scope? What would the minimum scope be for visual observation?
Should one consider a blue filter, red filter, or an infrared cut
filter as optimum. If we don't have an infrared cut filter what
other filters should be considered?