June 2011 - Utah-Astronomy - mailman.xmission.com

Grace satellites measure subsurface groundwater from orbit
by Canopus56 01 Jun '11

01 Jun '11

This is an interesting article from yesterday's New York Times Science section on the use of gravimetric satellites in orbit to make maps of subsurface ground water. NYT article http://tinyurl.com/43m6xjo NASA Grace satellite site http://grace.jpl.nasa.gov/information/ Clear Skies - Kurt

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NASA Image of Endeavor Docked
by stormcrow60＠xmission.com 01 Jun '11

01 Jun '11

Jay, Assuming this is the Northern Hemisphere, it appears to be Gygnus the Swan. Jon

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Endeavour Landing Quote
by Troy Davidson 01 Jun '11

01 Jun '11

I like to read the "Bad Astronomy" blog. I love Phil's views on things and the way he words things. This was very touching to me: "As I wrote when Discovery touched down for the last time: I’d say "Welcome home", but the ground is not a spaceship’s home." That is a great quote. http://blogs.discovermagazine.com/badastronomy/2011/06/01/endeavour-sets-wh… ++++++++++++++++++ Troy Davidson, KF7MTE www.istroyworking.com

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NASA Image of Endeavor Docked
by Jay Eads 01 Jun '11

01 Jun '11

I thought this was a pretty cool NASA image: http://www.nasa.gov/multimedia/imagegallery/image_feature_1961.html Anyone recognize the constellations or the location on Earth below? -- Jay Eads

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Tweet on Comets Win a Trip to Germany by ESO
by Jay Eads 01 Jun '11

01 Jun '11

The ESO is going to award a trip to their German headquarters to one lucky comet tweeter. This is from their site: "On 15 June, ESA will mark a quarter-century of comet science and say (temporarily) 'good night' to Rosetta with a special event at ESOC in Darmstadt, Germany. One talented Twitter user will be selected to join us as our guest at the event. Between now and 9 June, you're invited to tell us, via Twitter, why comets are cool. To take part, simply tweet your entry. It must include the "* #coolcomet*" hashtag<http://support.twitter.com/entries/49309-what-are-hashtags-symbols>, leaving you a mere 130 characters, so brevity is important. Your tweet may also include a single URL, or weblink, that links to a 'non-text' submission, such as a picture, image, photo, animation, video, audio file or any other sort of digital content. Maybe you can sing a song about comets, and submit a link to a video of you singing in YouTube? (The judges will look unfavourably on any content that takes longer than 3 minutes to view). We'll review all submissions and our expert judging panel will grade tweets for clarity, wit, humour, scientific accuracy and originality (and, yes, spelling counts)." Here is a link to the announcement: http://webservices.esa.int/blog/post/5/1332 Here is a link to the rules and details: http://www.esa.int/SPECIALS/ESOC/SEMB6UNSNNG_0.html There is also a second and third prize. - First: travel to ESOC, Darmstadt, Germany, and special guest invitation to comet event on the evening of 15 June (max value limited to €1000) - Second: Rosetta tee-shirt, poster, ball cap and coffee mug - Third: ESA memory stick Just thought since some members of the board are into comets this might be interesting. -- Jay Eads

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Re: [Utah-astronomy] couple of questions regarding CCD imaging
by Canopus56 31 May '11

31 May '11

> How do you achieve focus with a CCD camera since > there is no live focus mode? As Patrick and Joe note, all cameras come with some driver software that displays the current camera view with an option to change the length of exposure. Generally, again as Patrick and Joe note, it boils down to three cases: 1) There is bright star (mag. > 8.0) in the DSO image frame (occurs infrequently) Focus on the bright star with a short exposure time (e.g. 5 - 15 secs). The DSO will not exposure. Turn your focus knob in and out focus taking repeated images. When the bright star is a pinpoint, then you are at focus. Now up your integration time to expose the DSO. 2) There is no bright star in the DSO image frame but there is a faint star (mag. 11 to mag. 9) in the DSO image frame (most frequent case). Use the procedure above, but find _one of the faintest stars_ in the image field. When you are out of focus, the faintest star disappears. When the faintest star is out of focus it is a blurred disk, the star's disk brightness decreases, and the star merges with the background brightness of the image's field. You can see this effect with a telescope or binoculars by rolling the scope in or out of focus and watching what happens to the visibility of the faintest stars in the eyepiece. Now here's where motorized focuser controls come into play, if you are using a short focal length optical tube. Images are less forgiving to being out of focus as compared to visual observing. (The mind's wetware compensates for the blurred image.) Short focal length tubes have a very thin focus play - sometimes measured in less than one millimeter. Your hand cannot turn the focus knob accurately enough to get an ultra precise focus. The gear reduction ratio on a motorized focus controller can turn the number in 10ths of a millimeter and really gets the focus adjustment set exactly. 3) There is no faint star, just the DSO in the image (occurs infrequently). Slew off center until you find a faint star. Use the case no. 2 procedure to focus, then slew back to the target. Hope that additional explanation helps. Clear Skies - Kurt

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Re: [Utah-astronomy] couple of questions regarding CCD imaging
by Canopus56 31 May '11

31 May '11

Steve wrote: > My Crayford Type(Moonlite for SCT) will be here this week > and I can't wait to mess with it. Yep, it's still a time consuming process. Steve, I also own a single stage Moonlite focuser for a Newt. One thing to remember for all focuser types is the pressure plate or lock down setting. A camera can be relatively heavy, and depending on the angle of the optical tube in altitude, the camera can continually drag the focuser out of the precise focus point. I found this out the hard way with my Moonlite, and eventually I discovered the two recessed Allen wrench heads underneath the focuser's knobs. The Allen bolts push a pressure plate that ups the default tension on the Crayford rollers. Once I had added some more base pressure on the Crayford's plate, I had less trouble getting and keeping a camera in focus. But, it looks like the Moonlite SCT focuser has a simplier thumb-screw on the bottom to do the lock-down function. Clear Skies - Kurt

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