Posted 10 March 2013 - 05:30 PM
Posted 11 March 2013 - 09:03 AM
Posted 11 March 2013 - 10:16 AM
Posted 11 March 2013 - 01:01 PM
Posted 11 March 2013 - 03:27 PM
Posted 11 March 2013 - 03:28 PM
Your big aperture could potentially get you Mimas - quite the difficult prize. But you have high res so....
Posted 11 March 2013 - 05:32 PM
Posted 11 March 2013 - 08:07 PM
Posted 12 March 2013 - 12:44 AM
In fact, given the eight moons plus Saturn I wonder whether this is the maximum number of extraterrestrial, solar-system objects that can be recorded by an amateur astrophotographer in a single photo. Can anyone suggest a subject that would total more than these nine?
Posted 12 March 2013 - 06:27 AM
Posted 12 March 2013 - 10:16 AM
Posted 12 March 2013 - 03:45 PM
Wikipedia says the following about Amalthea:
"Amalthea was discovered on September 9, 1892, by Edward Emerson Barnard using the 36 inch (91 cm) refractor telescope at Lick Observatory. It was the last planetary satellite to be discovered by direct visual observation (as opposed to photographically) and was the first new satellite of Jupiter since Galileo Galilei's discovery of the Galilean satellites in 1610."
So, it sounds like a pretty difficult target even visually.
As far as I can recall, I've never seen an amateur-made photo that has shown more than the four Galilean moons of Jupiter. The maximum I've seen on Saturn is eight moons in a single photo (which I was able to do once with some difficulty, and I've seen a few who have done the same).
One additional issue to consider is that it is also possible for a moon to be effectively too far away from Saturn/Jupiter to be photographed in the same field as the planet itself (since you'll need a fair amount of magnification to see the inner moons). For example, Saturn's moon Phoebe has a magnitude of 17 but it is currently almost one half degree from Saturn and its orbital period is about 1.5 earth years so you'll have to wait maybe another three or four months before it will be close enough to capture with the other moons.
I've attached my annotated copy of the eight moons around Saturn, this was done with a 5 inch refractor and a series of five second exposures at ISO 6400 (it's been reduced in size to meet the Cloudy Night guidelines)
Posted 20 March 2013 - 03:12 AM
Being able to see the moons can be done even in very unsteady seeing if one is patient. Part of the reason I like them.
Posted 20 March 2013 - 03:43 AM
Posted 20 March 2013 - 12:09 PM
Yeah the moons can dance, but since they are point sources, they can be seen steadier at low magnifications.
At its current magnitude of over 11, it would be questionable but I don't think impossible. I never did a test to see what my deepest magnitude is at this site.
Posted 20 March 2013 - 12:12 PM
From the looks of it we may well have had more difficulty if mostly the light side was facing us. Perhaps it then may have been more like similarly sized Rhea which I have several times caught as a light spot against the darker limb shading in very good conditions and, with more difficulty, Tethys & Dione but soon lost further into the disk.
Someone later sent me a link to an image by a French observer, Christophe Guillou, on this report page 15/16 (scroll!): http://www.astrosurf...ix-Oppositio...
Due to its orbital geometry these events for Iapetus occur some two years before the edge-on rings and are very hard to catch. Phoebe’s orbit is currently closing and will be edge-on in 2016 but being considerably smaller than any of the above-mentioned – forget it; even if we caught it in going front/behind Saturn at the right time! Going to the JPL Solar System Simulator site and experimenting with the various settings you can find that, for instance, it is behind Saturn 2016 May 22. As I say beyond us; but the site will prove useful for those with ambition to catch and image it amid the other satellites. http://space.jpl.nasa.gov/
Posted 02 April 2013 - 01:29 AM