February 2005 - Utah-Astronomy - mailman.xmission.com

Re: [Utah-astronomy] the Pluto controversy continues
by astrodeb＠charter.net 15 Feb '05

15 Feb '05

When I saw Pluto in my 15" scope a few years ago I had to convince myself that I was looking at a planet in the solar system and not a speck of dust on my eyepiece. I feel now that Pluto is a large Kuiper belt object and not a true planet. Debbie > > From: Jim Gibson <jimgibson00(a)yahoo.com> > Date: 2005/02/15 Tue AM 10:34:02 MST > To: List <utah-astronomy(a)mailman.xmission.com>, > UVAA List <uvaa(a)mailman.xmission.com> > Subject: [Utah-astronomy] the Pluto controversy continues > > In light of discussions previously held on the list, here is another article on Pluto - Nothing new. > > http://www.cnn.com/2005/TECH/space/02/13/pluto.anniv.ap/index.html > > > > --------------------------------- > Do you Yahoo!? > Yahoo! Search presents - Jib Jab's 'Second Term' > _______________________________________________ > 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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Re: Re: [Utah-astronomy] the Pluto controversy continues
by astrodeb＠charter.net 15 Feb '05

15 Feb '05

Depends on how much Tequila one has drank. LOL. Debbie > > From: "Kim Hyatt" <kimharch(a)msn.com> > Date: 2005/02/15 Tue AM 11:20:25 MST > To: "Utah Astronomy" <utah-astronomy(a)mailman.xmission.com> > Subject: Re: [Utah-astronomy] the Pluto controversy continues > > So, how many angels can fit on the head of a pin? > > Kim > _______________________________________________ > 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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RE: [Utah-astronomy] Orion discounts
by Dale Hooper 15 Feb '05

15 Feb '05

Patrick, Any idea how long this discount is good for? I've had my eye on one of those little StarBlast scopes for awhile now. I might even let the kids use it occasionally. <g> But, I need a few more days to get the funds. Clear skies, Dale. -----Original Message----- From: utah-astronomy-bounces+dale.hooper=sdl.usu.edu(a)mailman.xmission.com [mailto:utah-astronomy-bounces+dale.hooper=sdl.usu.edu@mailman.xmission. com] On Behalf Of Patrick Wiggins Sent: Thursday, February 10, 2005 6:43 PM To: utah astronomy listserve Subject: [Utah-astronomy] Orion discounts I just received this from the folks that just acquired Orion Telescopes. Patrick As a special benefit to users of Starry Night, we are offering a one-time savings on select Orion telescopes, binoculars and accessories. Act NOW to take advantage of this introductory offer! http://www.telescope.com/coupon.jsp?code=IMN0251&URL=%2Fjump.jsp%3FitemI D%3D1%26itemType%3DHOME_PAGE Imaginova (parent company of Starry Night and SPACE.com) recently acquired Orion Telescopes & Binoculars. In celebration of this new partnership, we are offering 20% off select Orion telescopes, binoculars, and accessories. To receive your 20% discount, please enter coupon code IMN0251 in the coupon code field of the Orion shopping cart (the coupon code field appears on the Payment Information page of the shopping cart). If the coupon code already appears in that field, you do not have to reenter it. Discounted prices will appear in the Orion shopping cart, but not on product detail pages. _______________________________________________ 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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Re: Re: [Utah-astronomy] TeleVue 55 Plossl for sale
by astrodeb＠charter.net 14 Feb '05

14 Feb '05

A Celestron Super C8 Plus telescope, a Nikon Coolpix 4500 camera, Nikon MC-EU1 remote shutter control (brand new), and a Scopetronix 14mm eyepiece (brand new). Debbie > > From: Rob Ratkowski <ratkwski(a)hawaii.rr.com> > Date: 2005/02/14 Mon PM 03:21:58 MST > To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> > Subject: Re: [Utah-astronomy] TeleVue 55 Plossl for sale > > Hi Deb > > > I just forwarded your message to my friend Robert looking for a 55mm > TV. I have one and he loves that EP the most. What else you > selling?? I'll probably replace my EP's w/ Radians and Panoptics > over time, but as it stands I'm in good shape. > > It's cool here (only 70 w/ 15mph winds) and I'm just waiting for the > dark of the moon again. I have a couple simple projects in late > Feb/early March and I need dark. A few nights ago we were out and > got to see the Zodiacal Light, it looked like a sword thrust up into > the sky. Of course, no camera as this night out I was tired and > didn't want to drag more gear along (my MISTAKE!!) so I'll go shoot > the ZL and the Geigenshien (counterglow) and do a dark dark sky star > trail shot again. I keep having planes, boat and cars in the shot. > This place is getting too busy ....... > > > > Aloha > Rob > > _______________________________________________ > 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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TeleVue 55 Plossl for sale
by astrodeb＠charter.net 14 Feb '05

14 Feb '05

Time to clean out the closet so I thought I'd post it here before putting it on AstroMart. This eyepiece gives wonderful wide-field views. I saw the North American Nebula and the California Nebula with it last year. Debbie

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Re: Question on focus
by Canopus56 12 Feb '05

12 Feb '05

Brent Wilson wrote: > I have found that laser collimation is only a rough > alignment procedure. The final touch needs to be made > by eye, . . . As always - a final tweak to one's personal preference is done with eye. > . . . preferably using stars in the center of the field of view. A carefully marked mirror center and a peephole alignment . . . Nice trick with the star. I'll have to give it a try. I guess it's a matter of skill and experience. No matter what I do, laser collimation seems to get it that last bit that I can't do by eyeballing it. - Canopus56 __________________________________ Do you Yahoo!? Read only the mail you want - Yahoo! Mail SpamGuard. http://promotions.yahoo.com/new_mail

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Re: Question on focus
by Canopus56 12 Feb '05

12 Feb '05

Looks like that table on Sinnott's diffraction limited FOV width didn't go through listserv properly, so here it is in html: http://members.csolutions.net/fisherka/astronote/astromath/DiffractionLimit… - Canopus56 __________________________________ Do you Yahoo!? Meet the all-new My Yahoo! - Try it today! http://my.yahoo.com

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Re: Question on focus
by Canopus56 11 Feb '05

11 Feb '05

Patrick wrote, > If anyone is interested, I have S&T going back to > the first issue in my library. If y'all can come up > with the issue the article is in I'd be happy to > bring it to the next SLAS meeting The article I mentioned regarding the size of a scope's sweet spot was: Sinnott, Roger W. May 1991. Focus and Collimination: How Critical? Sky&Telescope pp528-531. Sinnott's equation for the diffraction limited field diameter for f/2 to f/10 scopes was - width_inches = 0.0007 * F^3 where F=focal ratio This works to the following for some common scopes at: In-focus sweet spot width F_ratio width_in width_mm %_1.25inFOV %_2inFOV 4 0.04 1 3 2 4.5 0.06 1 5 3 5 0.08 2 6 4 5.5 0.11 2 9 5 6 0.15 3 12 7 6.5 0.19 4 15 9 7 0.24 6 19 12 7.5 0.29 7 23 14 8 0.35 9 28 17 8.5 0.42 10 34 21 9 0.51 12 40 25 9.5 0.6 15 48 30 10 0.7 17 55 35 This also means that the fast mirrors scope have to be aligned within 1/10th of an inches or less or the image will degrade. Laser-aided collimation is a given. F/9 owners can drink heavily, horribly misalign their scopes by eyeballing and still have a passible image. -:) - Canopus56 __________________________________ Do you Yahoo!? Take Yahoo! Mail with you! Get it on your mobile phone. http://mobile.yahoo.com/maildemo

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Orion discounts
by Patrick Wiggins 10 Feb '05

10 Feb '05

I just received this from the folks that just acquired Orion Telescopes. Patrick As a special benefit to users of Starry Night, we are offering a one-time savings on select Orion telescopes, binoculars and accessories. Act NOW to take advantage of this introductory offer! http://www.telescope.com/coupon.jsp?code=IMN0251&URL=%2Fjump.jsp%3FitemID%3… Imaginova (parent company of Starry Night and SPACE.com) recently acquired Orion Telescopes & Binoculars. In celebration of this new partnership, we are offering 20% off select Orion telescopes, binoculars, and accessories. To receive your 20% discount, please enter coupon code IMN0251 in the coupon code field of the Orion shopping cart (the coupon code field appears on the Payment Information page of the shopping cart). If the coupon code already appears in that field, you do not have to reenter it. Discounted prices will appear in the Orion shopping cart, but not on product detail pages.

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RE: [Utah-astronomy] Question on focus
by Canopus56 10 Feb '05

10 Feb '05

David Dunn wrote, > I have seen this just looking at the moon itself. If > you are running much power, you will need to refocus > just to adjust for the curvature of the moon. If you are using a fast f/5-6 mirror, it may just be coma. The angular diameter of the in-focus "sweet" spot in the apparent field of view depends on focal ratio. The higher the ratio, the larger the in-focus sweet spot; the lower, the smaller the sweet spot. You usually do not notice the coma in deep sky fields because the dim stars do not provide a sufficient visual cue. The coma becomes easily seen with a large extended object like the Moon. For an f/9 mirror, the sweet spot can extend out to 3/4's of the apparent field of view. For a f/5-6 mirror in a DOB light bucket, the sweet spot may be less than 1/2 the apparent field of view. The coma problem inherent in fast f/5-6 light buckets is why the Teleview Paracorr "field flattener"/"coma corrector" is popular. http://www.cloudynights.net/lab/accessories/paracorr.pdf#search='corrector%20Paracorr' Suiter did a good article on the relationship between the size of the sweet spot to focal ratio in _Sky & Telescope_ in the late 1980s. I could not easily locate my copy but the article is referenced in the bibliography of Suiter's _Star Testing_ book. - Canopus56 __________________________________ Do you Yahoo!? Yahoo! Mail - Find what you need with new enhanced search. http://info.mail.yahoo.com/mail_250

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