August 2006 - Utah-Astronomy - mailman.xmission.com

Eyepiece recommendations?
by Seth Jarvis 29 Aug '06

29 Aug '06

Last weekend's star party at Capitol Reef was fantastic. Many heartfelt thanks to the SLASers who got it organized and for extending the invitation to join the event. Susie and I took our C11 to the star party and we were amazed by what that ultra-dark sky did for the telescope's views. I'm so used to doing star parties under so-so seeing conditions along the Wasatch Front that I'd forgotten what can be accomplished under a truly dark sky. I played around with the few relatively inexpensive eyepieces I own and found that by far the best views of the evening were achieved with a 1.25" 30mm Ultrascopic. Looking through Lowell's 10" Meade with his amazing Pentax eyepiece got me to thinking that perhaps I need to look into optimizing my C11's performance by getting better quality eyepieces. My problem is that there are a zillion eyepiece choices and I don't know what types of eyepieces are best-suited for a C11 and the sort of general-public viewing that dominates my use of that telescope. Anyone care to offer wisdom and/or opinions on the subject? (Any chance I can do this without going broke?) Thanks, Seth Jarvis

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Re: [Utah-astronomy] Eyepiece recommendations?
by Michael Carnes 29 Aug '06

29 Aug '06

Hi Seth, I heard your joyous exclamations throughout the evening at Capitol Reef, but I don't believe you ever made it to my scope. You do know you've asked a variant of the most dangerous question in astronomy---what should I buy? First, here are a couple of good online review sites: http://www.cloudynights.com/ http://www.scopereviews.com/ Second, you should determine what it is you want to see -- widefield deepsky, lunar, planetary nebula, planets, etc. There's a different ideal eyepiece for each application. Lowell's Pentax is indeed a great eyepiece. You'll notice if you go onto any online sales site that there are many different types of Pentaxes--each with a different (ahem) focus. You'll also find Televue Naglers which are equivalent in quality. But if you're looking for strong detail on the lunar surface, you'll find that many people will recommend something with less glass -- a simple plossl or even an orthoscopic. Third, the C11 is a pretty forgiving scope in terms of eyepieces. Its F/10 focal ratio means that you can use a pretty long focal length eyepiece. WARNING: SIMPLE MATH. Take the focal length of the eyepiece and divide by the focal ratio of the scope. That will give you the exit pupil--that's essentially the size of the image. If the exit pupil is larger than your own pupil, you're just wasting light. A "mature" person may have a maximum dilation of 6 or perhaps 7 mm under very dark skies. So a 35mm eyepiece with an F/10 scope will give you a 3.5mm exit pupil. Nominally that sounds OK. But with a Schmidt-Cassegrain scope, you may begin to see the central obstruction (which is manifested as a difficult-to-hold image) at less than the maximum exit pupil. I experienced a little of this looking through Lowell's scope. Guess I just need new eyes. On the other hand, if you throw a 7mm eyepiece in a C11, you're almost never going to have a night that gives you a decent view at such high magnification. Fourth, you've got plenty of time. Make a nuisance of yourself at SLAS star parties. Try out different eyepieces, though your scope or a similar scope. See what you like. It's a real pity to load up on expensive eyepieces and then find out you only use one or two of them. Finally, I will throw in my 2-cents' worth. A good widefield eyepiece in the 20-21 mm range will give you excellent views and will work in just about any scope. Another good range will be the 13-14 mm range. Once you get under 10mm or so, you enter the high-power world and will have to do some serious investigating of your needs and preferences. Once you get up past 30mm, you really need to try the eyepiece in your scope. Michael -----Original Message----- >From: Seth Jarvis <SJarvis(a)slco.org> >Sent: Aug 29, 2006 12:52 PM >To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> >Subject: [Utah-astronomy] Eyepiece recommendations? > >Last weekend's star party at Capitol Reef was fantastic. Many heartfelt >thanks to the SLASers who got it organized and for extending the invitation >to join the event. > >Susie and I took our C11 to the star party and we were amazed by what that >ultra-dark sky did for the telescope's views. I'm so used to doing star >parties under so-so seeing conditions along the Wasatch Front that I'd >forgotten what can be accomplished under a truly dark sky. > >I played around with the few relatively inexpensive eyepieces I own and >found that by far the best views of the evening were achieved with a 1.25" >30mm Ultrascopic. > >Looking through Lowell's 10" Meade with his amazing Pentax eyepiece got me >to thinking that perhaps I need to look into optimizing my C11's performance >by getting better quality eyepieces. My problem is that there are a zillion >eyepiece choices and I don't know what types of eyepieces are best-suited >for a C11 and the sort of general-public viewing that dominates my use of >that telescope. > >Anyone care to offer wisdom and/or opinions on the subject? (Any chance I >can do this without going broke?) > >Thanks, > >Seth Jarvis > >_______________________________________________ >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://www.utahastronomy.com

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New Nova on line
by Patrick Wiggins 29 Aug '06

29 Aug '06

The SEP/OCT 2006 issue of Nova is now on line. Look for it to show up on the SLAS site soon but for now it's located at http://utahastro.info/slas/nova/so2006/NOVASO2006.HTML. Provided no one reports any typos I plan to have the paper copies in the mail by the 31st. Editor Patrick

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"Xena" picture
by Patrick Wiggins 29 Aug '06

29 Aug '06

I was surprised to learn that despite dwarf planet "Xena" being so much further away than Pluto that it actually shines at a relatively bright magnitude 18.5. Pretty bright for something 97 AU out there and further than any other known solar system object. 18.5 is well within the reach of many amateur set ups so this morning I decided to give it a go. I only had a few minutes between the time it cleared my roof and slid behind the trees so I didn't even have time do do much focusing. But still, in just 2 minutes I was able to get a so-so image: http://www.trilobyte.net/paw/slas/patrickw/PATRICKW1006.JPG If the weather holds I'm going to try to be a bit better prepared tomorrow morning and try for a better shot. pw

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Re: [Utah-astronomy] Having trouble with UA posts
by Patrick Wiggins 29 Aug '06

29 Aug '06

Canopus56 wrote: > Patrick, Do you have the 2007 star party schedule > approved at the last meeting. (I'm updating my astro > calendar and would like to get the dates in.) - Kurt Hi Kurt, Yep, it's in the new Nova: http://utahastro.info/slas/nova/so2006/NOVASO2006.HTML And also posted near the top of: http://utahastro.info pw

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Having trouble with UA posts
by Patrick Wiggins 28 Aug '06

28 Aug '06

I am not receiving copies of messages posted to UA (not even copies of my own posts). It looks like the problem started sometime Friday. I'm not sure if the problem is with the list or my ISP. I've reported the problem to Listmeister Cynthia but, in the mean time, if anyone posts some witty piece of repartee to the list they'd like me to see they'll need to cc me a copy. pw

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They were right! (Moon Mars last night)
by Patrick Wiggins 28 Aug '06

28 Aug '06

Image caption: Excited observers watched and pointed last night (27 AUG 2006) as the Moon and Mars put on quite a show: http://utahastro.info/temp/MOONMARS.JPG pw

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More Pluto humor
by Patrick Wiggins 27 Aug '06

27 Aug '06

It's nice ot see that some are actually having fun with what came out of Prague. CAUTION: Conservatives will not want to go here (Siegfried, Guy, you've been warned <grin>): http://www.borowitzreport.com/archive_rpt.asp?rec=6574&srch= pw :)

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Sore losers? (humor)
by Patrick Wiggins 26 Aug '06

26 Aug '06

Pluto Loses Designation, Sues IAU In a move that surprised many legal observers, one of Pluto's leading public-interest groups yesterday sued the International Astronomical Union after the IAU declassified Pluto as one of the nine "classical" planets that circles the Sun. It is not yet known where venue for the case ultimately will be placed or precisely which judge eventually will hear the case. "The IAU isn't the end-all, be-all for the solar system," said a public relations spokesperson for Pluto, appearing on CNN's Larry King Show. "You can't just un-designate a planet without giving folks on the planet an opportunity for due process, and the right to be heard, and to challenge the facts upon which the decision is based." The complaint alleges that the IAU violated key provisions of the Administrative Procedure Act, federal constitutional law, and certain Plutonian legal principles that are too complicated to set forth here. "We reject the downgrade from classical planet to 'dwarf planet'," the Plutonian flak told King. "We have a right to self-identity, to call ourselves whatever we want to call ourselves and not allow some pointy-headed scientists on Earth to label us. We feel confident that a jury on Earth or on Pluto or on any other planet will see through the IAU's discrimination and in the end give us celestial justice." Apparently, Pluto has contacted Mark Geragos to see if he will take the case. Quoted from: http://blog.washingtonpost.com/benchconference/2006/08/pluto_loses_designat…

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Nectarines -- especially for Patrick
by Joe Bauman 25 Aug '06

25 Aug '06

Patrick (and all others who care), what my very educated mother just served us is -- nectarines! I was getting a haircut this afternoon at Great Clips in Foothill Village, and Susan, the woman who was doing the honors, asked me what I do. I told her I'm a reporter, covering science and the environment, and naturally the discussion went in the direction of Pluto. I told her about your quest for a substitute with three syllables that starts with N, and she came up with nectarines. She then supported the choice by saying nectarines are healthy, and an educated mother would serve nectarines. So that's a pretty good one, I think. Best wishes, Joe

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