April 2008 - Utah-Astronomy - mailman.xmission.com

Visit the Footes Friday?
by Patrick Wiggins 29 Apr '08

29 Apr '08

Anyone interested in a flight down to visit Cindy and Jerry Foote in Kanab this coming Friday afternoon? Leaving from SLC International's Executive Terminal (east side of the airport) in early afternoon, touring the Foote's two observatories and having lunch mid afternoon and back to SLC by early evening. Clear skies! patrick

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Re: [Utah-astronomy] SPOC tonight (last Saturday)
by Canopus56 28 Apr '08

28 Apr '08

Patrick wrote: > I'm looking forward to seeing Saturn through the big refractor. Saturn was particularly good last Saturday. With anal retentive collimation I was able to bump up a 10" Newt to 300 power using a 4 mm TMB ep and see a great level of detail on Saturn's disk - many cloud bands on the disk and the major divisions in the rings. Didn't notice the Saturn "white spot" refered to in this April 20 image taken by Greek uber imager George Tarsoudis, but the spot could have rotated out of view. http://www.lunar-captures.com/saturn2008/080420_saturn_spot_tar.jpg - Kurt PS - (I didn't get around to resetting the cone error adjustment after recollimating over the winter, so the GOTO pointing of the mount was not useable on the Virgo galaxies. Reset the cone error on Sunday afternoon.) ____________________________________________________________________________________ Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now. http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ

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SPOC laser
by Chuck Hards 28 Apr '08

28 Apr '08

A few of us were at SPOC last night; Chris Clark was giving a refresher course for the 32" (many thank, Chris!). It was the first time I've had a chance to use the big scope since Bruce installed the laser pointer. It is installed inside the telescope "cage" such that the general public can't easily access it. The remote switch is conveniently located near the eyepiece, and Bruce has installed a long tube on the front to eliminate glare. I actually used it as a "finder" on two objects and it worked very well for that purpose. It's primary purpose is to show guests where the telescope itself is pointing. The only way anyone could be exposed to the beam is if they were on the top of the observatory wall and the telescope happened to be pointing directly at them. The public and telescope operators can't be exposed to the beam on-axis. Many thanks to Bruce for a thoughtful, safe, and functional installation!

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Re: [Utah-astronomy] When laser operators go wild
by Canopus56 28 Apr '08

28 Apr '08

Australia reacts, bans GLPs for amateur astronomy - http://news.yahoo.com/s/nm/20080421/tc_nm/australia_lasers_dc Australia is not kidding. - Kurt ____________________________________________________________________________________ Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now. http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ

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Re: [Utah-astronomy] kudos to "Killer Ken" Warner
by Gary Vardon 27 Apr '08

27 Apr '08

The idea of distributed computing as exemplified by SEIT has a lot going for it. Difficult computing challenges can be tackled by this approach. Sincerely, Gary Vardon see my website www.wealthbuilder.wwdb.biz use gary1234 as the access code -----Original Message----- From: Chuck Hards Sent: Friday, April 25, 2008 9:49 PM To: Utah Astronomy Subject: Re: [Utah-astronomy] kudos to "Killer Ken" Warner Not to take anything away from Ken's or other's dedication, but seti@homehas been off my radar for a few years, since I heard they were sending out old, already processed data as "make work" due to too many volunteers and not enough fresh raw data. Is this still the case? Any probable hits yet? On Fri, Apr 25, 2008 at 6:19 PM, Ken Warner <killerken(a)killerken.com> wrote: > Thanks Rich. It helps when you have several high end computers at your > disposal. I'm currently ranked 2998 in the world and 809 in the United > States. I also surpassed 1 million recently in PrimeGrid too. Now for the > next million, September 13, 2008 at my current rate. :-) > > _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy(a)mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://gallery.utahastronomy.com Visit the Wiki: http://www.utahastronomy.com

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Re: [Utah-astronomy] Color images
by Jerry Foote 27 Apr '08

27 Apr '08

One thing I failed to mention is that many of us use only scientific filters (UBVRI) in our cameras yet these same filters can still produce very nice images. Again it is how you expose the images through the filters and how you combine them into the final image. Patrick you can have your cake and eat it to. Also the reason for median combining is to eliminate any cosmic ray hits that occur in the flats. As for the number of flats or darks that will be combined to form a "master" flat or dark, remember the noise reduction that occurs with using multiple images decreases as the square root of the number of images used. Thus using 15 images reduces the noise by 3.87 (16 images would reduce it by 4). Jerry Foote ScopeCraft, Inc. 4175 E. Red Cliffs Dr. Kanab, UT 84741 435-216-5450 jfoote(a)scopecraft.com

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Color images
by Jerry Foote 27 Apr '08

27 Apr '08

Hi Patrick, Ok, some basics. Since we humans have been pre-conditioned to see in a particular spectral band of the E-M spectrum, ie., everything we see with our eyes has been illuminated by the light from a G2 type star, the usual approach is to do a color balance of images to reach a "pleasing" image as if was illuminated by a G2 type source. A G2 star should be "white". Now to reach this balance the best thing is to take a series of images through your filters at a G2 star and then determine the ratio of exposures for each filter which leads to a "white image of the G2 star. Using the inverse of these ratios referenced to one of them, usually the red filter leads to the correct exposure time for each filter. But wait there's more. There must be sufficient signal of the object being imaged to attain an image that isn't overrun by noise. So this means that the filter that produces the least signal must be exposed sufficiently to attain the detail needed for the final composite image. Many use stacking and dithering to attain this signal and to also average out the noise in the individual images. However be careful as stacking only works if there is sufficient signal to add that will arise above the noise. Remember the signal increases as the number of images increases but the noise only increases as the square root of the number of images. But you gotta have signal! So where does this lead in the real world. Looking at the response curves of the combined CCD and RBG filters, there will be more signal in Red than in Green and than in Blue. The ratios go back to the G2 images and you must do the math to work out the precise numbers, or use AIP4WIN which has a nifty calculator. Getting back to our eyes however, it turns out that our eyes are much less sensitive in resolution in color than in illumination. So this leads to LRGB images in which an object is exposed at as high a resolution (1x1 binning) as possible in "luminance" (no filter) and lower resolution (2x2 binning) in the RGB filters. Bringing all of the resolutions to the same level (1x1) and then combining them leads to a pleasing image to our eyes. The 2x2 binning also helps with the exposure times through the filters. Narrow band filters are handled much the same however one must "assign" particular visual colors to each filter pass band. Think of radio telescope images, the composite image has had the particular pass band assigned to a particular visual color. In the final analysis the "beauty is in the eye of the beholder". Pretty astronomical images are really art and not science so working with the individual images to reach a pleasing composite is really the work of the artist. Consider the differences between observing the Giant Red spot on Jupiter and images taken with space craft. Jupiter has been illuminated equally by our Sun and the light reflected has come through empty space with only a small amount of attenuation by our atmosphere, yet the Red Spot is much better defined after the images have been enhanced by the "artist" (NASA). Jerry Foote ScopeCraft, Inc. 4175 E. Red Cliffs Dr. Kanab, UT 84741 435-216-5450 jfoote(a)scopecraft.com

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solar videos
by Gary Vardon 27 Apr '08

27 Apr '08

Fellow SLASers, Google living in the atmosphere of the Sun. You'll see awesome videos of solar phenomena. Sincerely, Gary Vardon see my website www.wealthbuilder.wwdb.biz use gary1234 as the access code -----Original Message----- From: erikhansen(a)TheBlueZone.net Sent: Saturday, April 26, 2008 10:11 AM To: Utah Astronomy Subject: Re: [Utah-astronomy] OT: Parachutes and rocket packs again >James Bond had that years ago. On 25 Apr 2008, at 18:38, Canopus56 wrote: > >> Something to make the commute a little easier and more >> entertaining: >> >> Attack Wing: Glider Makes Waves With Stealth and Speed >> http://www.foxnews.com/story/0,2933,352477,00.html >> >> Attack wing glider video: >> http://www.foxnews.com/video2/video08.html?videoId=0ce238b2- >> cc7d-4c94-9b94-0cda51193130&sMPlaylistID= >> >> - Kurt > > Ok, as long as we're going on about crazy things in the sky: > > Man skydives with turbine engines strapped to his feet. > http://video.google.com/videoplay?docid=-5417019303200331106 > > Catapult Skydiving > http://www.toxicjunction.com/get.asp?i=V3586 > > pw :) > > _______________________________________________ > Utah-Astronomy mailing list > Utah-Astronomy(a)mailman.xmission.com > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy > Visit the Photo Gallery: http://gallery.utahastronomy.com > Visit the Wiki: http://www.utahastronomy.com > _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy(a)mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://gallery.utahastronomy.com Visit the Wiki: http://www.utahastronomy.com

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Color CCD picture question
by Patrick Wiggins 26 Apr '08

26 Apr '08

To those here that shoot tri-color CCD images: Is there a rule of thumb for how much time to be spent imaging through each filter (red, green, blue, clear)? patrick

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SPOC tonight
by Patrick Wiggins 26 Apr '08

26 Apr '08

A reminder that SPOC will be open tonight from dusk to 11:00 p.m. I'm looking forward to seeing Saturn through the big refractor. http://slas.us/maps/SPOCMAP.HTM patrick

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