[X] My Assistant

[elakdawalla]

Hi everybody,

I was talking with Amanda Hendrix at JPL today about the upcoming icy satellite encounters, and she asked me if I had any way of getting in touch with amateur observers. They are looking for people to do photometric observations of Hyperion for several days on either side of the flyby. She said: "Ground-based observing will help to constrain the current state of rotation of Hyperion, whose spin axis changes. The visual magnitude of Hyperion is 16.5, so serious photometry would require at least a 24-inch telescope."

Gulp. That's a big telescope, and short notice, with the encounter only 6 days away. I'm not an observer so I don't know how to get in touch with lots of amateurs with big scopes except for the couple of people I know personally. Can anybody on this board help get the word out?

--Emily

[tedstryk]

Hi everybody,

I was talking with Amanda Hendrix at JPL today about the upcoming icy satellite encounters, and she asked me if I had any way of getting in touch with amateur observers.  They are looking for people to do photometric observations of Hyperion for several days on either side of the flyby.  She said: "Ground-based observing will help to constrain the current state of rotation of Hyperion, whose spin axis changes. The visual magnitude of Hyperion is 16.5, so serious photometry would require at least a 24-inch telescope."

Gulp.  That's a big telescope, and short notice, with the encounter only 6 days away.  I'm not an observer so I don't know how to get in touch with lots of amateurs with big scopes except for the couple of people I know personally.  Can anybody on this board help get the word out?

--Emily

I wish I could, but I have only a 10 inch scope and no equiptment that could do photometry anywhere close to 16.5 magnitude.

[hendric]

Emily,
One place to try is the Minor Planets Mailing List on Yahoo! Groups. There are quite a few semi-pro (I would classify anyone with a 2 foot mirror semi-pro!) there, and they some are very familiar with photometry:

http://groups.yahoo.com/group/mpml/

[um3k]

I only have a 3.5 inch telescope.

[elakdawalla]

Emily,
  One place to try is the Minor Planets Mailing List on Yahoo! Groups. 

Thanks for the suggestion, I've sent a message to Richard Kowalski. --Emily

[odave]

You could also try contacting amateur astronomy clubs - some of them have pretty advanced equipment. I'm not a member, but the University Lowbrow Astronomers in Ann Arbor have a 24" scope and certainly have the experience with photometry...

[tfisher]

I sent a request to get this posted at hohmanntransfer.com, which is a site listing news especially related to amateur observers of minor objects. The moderator is currently at a low pace of updates, but hopefully this gets posted quickly.

Emily, can you find out what the best way for people to submit photometry results back to Dr. Hendrix?

[elakdawalla]

Emily, can you find out what the best way for people to submit photometry results back to Dr. Hendrix?

I am checking! Thanks!

For those of you whose scopes aren't big enough -- you're still one up on me. I don't even own a telescope. And I am deeply ashamed to admit that I have gazed through a telescope at a planet only three times in my life.

--Emily

[djellison]

I trained the world-leading power of my 114mm reflector-with-a-dent-in-the-tube on Mars last night.

Conclusions from the exercise "ooo -it's all beige"



Doug

[scalbers]

I am checking!  Thanks!

For those of you whose scopes aren't big enough -- you're still one up on me.  I don't even own a telescope.  And I am deeply ashamed to admit that I have gazed through a telescope at a planet only three times in my life. 

--Emily

You might also try the American Lunar and Planetary Observers (ALPO), perhaps at their minor planet section.

http://www.lpl.arizona.edu/~rhill/alpo/minplan.html

I also have to admit I've been slacking off the past few years with planetary observing. Hope you get a chance to do some more, as the skies on So. Cal are generally steadier than here in Colorado. There was one interesting opportunity a year and half ago, at the Sommers-Bausch observatory after a talk by Carolyn Porco. The group was anticipating taking a look at Saturn - too bad it was cloudy!

[elakdawalla]

Emily, can you find out what the best way for people to submit photometry results back to Dr. Hendrix?

Here's what Amanda said:

We need closely spaced, reduced apparent R magnitude vs time, starting now through the Cassini flyby (Sept 26), until ~mid October. The photometry results will be used to ultimately derive the current period of Hyperion, which will help with interpretation of the Cassini data. Reduced results can be sent to Bonnie Buratti (Bonnie.J.Buratti@jpl.nasa.gov).

I'll forward the information on ALPO to her.

[elakdawalla]

It turns out there's hope for people with smaller telescopes after all. I got this in an email from Anne Verbiscer yesterday (she's the U. of Virginia planetary astronomer who did those Earth based opposition effect studies of Saturn during Earth's central transit across the Sun as seen from Saturn in January):

I took a look at your online entry calling for observations of Hyperion and found that you might be discouraging some potential observers by saying that they need to have a telescope 24-inches or larger.  One may need a substantial telescope in order to see Hyperion through an eyepiece with your own eye, but a CCD on even a modest (~ 8") telescope can make a long exposure and observe Hyperion quite easily.

Also, not to nitpick about numbers, but a quick check (i.e. Google) on the V magnitude of Hyperion comes up 14.2, not 16.5. That is an estimate of its magnitude at opposition (which we are nowhere near... the phase angle now is more than 6 deg.), so it will be dimmer than 14.2, but not by more than 2 magnitudes.

--Emily

[odave]

That's true, but I wondered if the eposure length would impact the data, and if having something bright like Saturn nearby would saturate the camera. I've never tried to image any of the moons by themselves - anyone else?

I may give it a shot, though my camera dates from those ancient days when a 640x480 CCD was considered "good" amateur equipment (1998).

[tedstryk]

That's true, but I wondered if the eposure length would impact the data, and if having something bright like Saturn nearby would saturate the camera.  I've never tried to image any of the moons by themselves - anyone else?

I may give it a shot, though my camera dates from those ancient days when a 640x480 CCD was considered "good" amateur equipment (1998). 

Other than being hard to aim, 640x480 really isn't a problem, since Hyperion will be a point source anyway! In fact, in planetary imagery, it is best to not magnify the image beyond the point that maximizes your telescope's resolution in the seeing conditions, because any enlargement beyond this simply spreads the light over more pixels, leading to a fainter image, and hence requiring a longer exposure time, allowing more impact from atmospheric seeing conditions.

[malgar]

Paolo Tanga
post-doc at Observatoire de la Côte d'Azur, France
Laboratoire Cassiopee, CNRS
Equipe Planétologie et systèmes dynamiques (Planetology and Dynamical Systems) reports this:

"Saturn is not very far from conjunction, at 50 degrees from Sun, that seems a lot but they are quite littles to observe it in the sky.
Hyperion, in these geometrical conditions, doesn't reach 2' of elongation from Saturn. They are very littles to don't be disturbed by the planet's light.
Photometric precision required is high and not easy with little diameters.
BTW, those with a really good equipment (cooled CCD, big and good telescope) could try."

Sorry for my very bad translation...
Bye,
Ale.