From: "milton_aupperle" <milton@outcastsoft.com>

Date: September 26, 2009 9:22:40 AM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: Online Asteroid Resources

--- In Astro_IIDC@yahoogroups.com, Mark Gaffney <markgaffney@...> wrote:

Hi Milton,

I`ve been looking at them & both Sky Tools 3 Pro & The Sky X SAE for  

Mac have the facility to import asteroid databases. 

So do other apps like Equinox or SNP. Those online resources generally give you a lot more more information, like rotational period and magnitude variations for the rotation, real magnitude and phase angle which the apps I use don't have. If an asteroid is very round (like Ceres), you get minimal magnitude change due to rotation, so it's a poor target when starting out doing light curve capture. You want an Asteroid with lots of variation, like Eros which had variations of up to 1.4 magnitudes over 5 hours, which is easy to detect.

Sky Tools will  

display the optimum ones for your observing position for the night (&  

you can generate current lists) then you can find the object on the  

Interactive Atlas & presumably slew to them. Such objects as Io,  

Metis & Lutetia (ones I`ve recorded on my sheet of paper here) are on  

your list & are amongst the 11 objects displayed on my ST list.

You might want to check the magnitude of them, as most asteroids are 11th to 15th magnitude or fainter and are generally not visually detectable. I've also seen discrepancies between the Apps expected magnitude and the one that NASA came up with too. My C8 under perfectly dark skies can theoretically reach down to Magnitude 14, but that doesn't mean my eyes (or yours or anyones) are that sensitive.

I`ve  

only briefly looked at it but the magnitude, constellation & rise  

transit & set times are there also. None of the objects on the list  

are described as being visually detectable in with my C9.25. I guess  

that`s a matter for using a time exposure of some kind.

With the Grasshopper EXHAD camera, brightness / gains cranked up quite high and binned 4x4 I can easily capture Mag 14 to 15 stars with 1 second exposures on the C8, unguided.

Does your  

Starry Night app. have something along these lines?

I use either Equinox or SNP for determining what asteroids are up at specific times. I like the way SNP is set up for selecting guide stars down to magnitude 9 in relation to my field of view of the Camera and the OAG. Then I use the online resources to determine if they are worth generating a light curve for. I'm still learning what exposures I need to gather the best data, how good my tracking needs to be, what sorts of skies (turbulence, haze, smoke etc.) can I tolerate to still generate good data from and how to process the data to get good information out.

I'm also going to have to start connecting up the HEQ5 hand controller to the mount with the Keyspan adapter and let SNP or Equinox move my mount to the target now too, as entering coordinates in manually with the hand controller is a PITA.

TTYL..

Milton Aupperle