From: "cosmicrock2001" <ursamajor_1@mac.com>

Date: September 30, 2009 3:03:13 PM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: [IOTAoccultations] Video Recording planning and preprations for the LCROSS i


There are good guides and image-maps here:


http://groups.google.com/group/lcross_observation/web/observing-how-to


and


http://home.comcast.net/~dave.dockery/Imaging%20%20the%20LCROSS%20Impact%20Event.pdf


I havent had a chance to read through all this yet. But due to suggested magnitudes and nebula like form, I'm thinking maybe I should use my DSI-Pro monochrome camera which is 16 bit and more sensitive than the DBK.  I can run it with Nebulosity on my Mac. Using an IR pass filter with it may help the seeing and the help separate the 'nebula' plume from the background moon in near IR or longer red wavelengths the camera is sensitive to.  I normally just use the DSI for guiding.


The LCROSS amateurs guide suggests setting exposures to capture nebula so that might mean 2 seconds or more? I think it might depend if the plume is seen against a bright lunar background or black shadow or black space above the limb.  Definitely need to run some tests and trials over the next few nights.  


Ron


--- In Astro_IIDC@yahoogroups.com, "milton_aupperle" <milton@...> wrote:


Hi Folks;


One issue I'm running into a lot is that the perspective images don't really show where "Cabeus" is. They all show "Cabeus A" or "Cabeus A1" or "Cabeus B", but not "Cabeus" proper. And the flat maps don't indicate what direction is North or where the south pole is for a point of reference.


I just found a decent shot of it here (scroll to the bottom of the page for crater names):


http://www.lpod.org/?m=20070106


which shows "Cabeus" in profile and in relation to Moretus, Short and Newton. So now we have a reference.


I'd also suggest that tonight or tomorrow anyone who wants to image the event to try a quick and dirty practice shoot with different exposures and focal lengths of this area. At least you have some idea what to expect when on October 9.


The maximum height the plume will be is about 18 arc seconds (35 km) from the crater floor and estimated brightness will be in the Mag 3 to Mag 9 per square arc second. So they expect the plume to be more like a nebula and in the range of M42 to M27 in brightness. Even if you can't "see" the plume, it may cast a shadow or even partially obscure the brightly lit crater rims and look like a dark moving curtain (relative to the surrounding landscape that is).


Note that these are all "guesses" by Nasa. They don't know the depth of the dust in the crater, it's reflectivity (if it's all anorthosite / highland material, it would be a lot brighter than say volcanic ash or crushed mare material) how high it will be thrown or how fast it will disperse. They also don't know exactly where the impactor is going to land yet either on the crater floor.


So we may see absolutely nothing or we might get lucky and capture something like what happened when they whacked that comet with the impactor and it spewed up a tonne of material.


It will be interesting to capture it anyhow.


TTYL..


Milton Aupperle


--- In Astro_IIDC@yahoogroups.com, "cosmicrock2001" <ursamajor_1@> wrote:


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?