From: Mark Gaffney <markgaffney@me.com>

Date: September 26, 2009 2:40:41 PM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] Re: Online Asteroid Resources

Hi Milton, I looked at The Sky X SAE for Mac in more detail after writing also. It has a small & a large Database of asteroids. The large one will take you to 2 links; http://asteroid.lowell.edu/ & http://www.cfa.harvard.edu/iau/MPCORB.html which you can use to add data useable in the sky window. It has this ability which The Sky 6 also has of being able to draw rings around objects according to different offsets & make boxes for the size of your camera`s FOV for use with an OAG as you say SNP has also. I think the Pro version is out soon if not already (I haven`t checked it recently as I can`t afford the upgrade at present). The asteroids listed in ST3 for my location were all 11th magnitude or less I think. ST3 Pro`s exposure calculator will also be very useful. I was looking at the EC window for Io (I guess this is not the moon of Jupiter..?). You can calculate SNRs & different subexposure possibilities for it`s enormous DVD sized database of objects. I had the details for the  Flea 2 very kindly sent me by a Danish guy on the ST group which he`s read from the spectral sensitivity graph on the PGR technical manual I`ve obtained (Greg Crinklaw was getting around to doing it). I`ve had a look at it & may be able to do it myself in future. There`s probably more to it I`m not familiar with yet-I did find various asteroids on the Interactive Atlas & telescope windows as well as on The Sky X`s sky windows last night. You can have The Sky draw tracks for any number of asteroid orbits for example. Now I`ve got my PA to be quite respectable I hope to start experimenting with telescope controls for the above 2 apps & Carina Voyager as well, both with my Bluestar Adapter & with the apps on the iPod. I have a Tiger version of Equinox 6 on the iBook now too (I hope to be able to upgrade the HD to a larger size-it`s only 30 GB at present of which I have 11 left! as well as a RAM memory upgrade which will enable me to load Leopard. If bought with a Superdrive upgrade(DL) at MCE you can save some money. I think I`d pay the local Apple shop to install these upgrades-I`ve gained some confidence dismantling my telescope tube recently but the anti static wrist bands & fiddly sets of screws seem a bit daunting! Next week by the way I hope to be able to purchase my 2nd copy of Astro IIDC for the iBook...

Mark.

On 27/09/2009, at 1:22 AM, milton_aupperle wrote:

--- 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