January 2009 - Utah-Astronomy - mailman.xmission.com

Gallery news
by Patrick Wiggins 07 Jan '09

07 Jan '09

I just heard from Cynthia. She says she's searched and can find no images that survived the U-A Gallery's server crash. patrick

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Re: [Utah-astronomy] 13.1 inch Coulter Carcass, free
by JayLEads 07 Jan '09

07 Jan '09

A lot to think about. I want at some point to make my own scope and yes, grind my own mirror. See, as a teacher I get these LONG three week breaks throughout the year (one basically in each season) and after getting done with the honey do's and my own do list, I get really bored and have a couple of weeks to kill (I do sub and that pays for this hobby). Anyway, I think this would be a really interesting project to tackle and as others have said, it won't be one the first time I want to do alone. So I'll wait. Good things always result from waiting. Thanks for the advice. Also, when I do it, I want to build it for me, and not go in with others on one scope. I would go in on purchasing materials if it means we got to get going. Guess we or I would need a teacher first. Jay On 2009-01-08 00:53, Chuck Hards wrote: > The wrong ladder in the dark can definitely be hazardous, but that's not > exactly a problem with a long-focus telescope; it's the wrong choice of > ladder. The right choice might not be easily transported, or even easily > used at the eyepiece, so that's one of those choices people make. > > I think the original context of the question was short focal- length mirrors > as a first effort at mirror grinding. They do take more work and can be > more difficult to figure, but it's not out of reach of the average person, > given the proper guidance. If, however, one is purchasing a > commercially-made mirror, all the caveats of fabrication can be ignored. > > I don't agree that deep-sky observing is better at f/4, as a blanket > statement. My little RFT is an f/5 and the coma is noticeably less than > otherwise identical telescopes I built at f/4, yet the field isn't much > smaller using the same eyepiece. > > I also don't weigh my equipment choices against their fit at a public star > party. I'm kind of selfish with my astro-time- my personal enjoyment is my > prime motivation. I'll blow-off being "star-party correct" in a heartbeat > if I feel I can get some kind of advantage by doing so. On nights when I'm > specifically doing the public outreach job, then convenience and safety > will trump imagery out of necessity. > > The telescope must be designed for it's intended use. One person's > trade-off list will probably not correspond one-for-one with someone elses. > > On Wed, Jan 7, 2009 at 1:59 PM, <zaurak@???> wrote: > > > The narrow steps on a ladder can take a toll on your feet in the course of > > a night. The classic dobson is long focal length, but there are many > > companies that do a good job on fast optics in the 4f range. Deep sky > > observing is better with f 4's. > > > > Tall ladders seem a liability for public star parties. > > > > > > >

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Re: [Utah-astronomy] Utah-Astronomy Digest, Vol 71, Issue 19
by Robert Taylor 07 Jan '09

07 Jan '09

In my case the 16" F/4.45 was my first attempt at making a telescope and mirror and it turned out very well. I had a lot of help from John Zeigler and made it as part of his class a few years ago. The best planet views I've ever had were with that scope so it not just a great deep sky scope. It has served and continues to serve me well. Coma is visible but Naglers solve the problem, a Parracor is another option to handle Coma and will provide more flexibility on eye pieces but I used it as a justification to get some good eye pieces. I don't have a parracor, the coma just doesn't bother me that much. I still use lesser EPs and just ignore the coma. I have used big Dobs with ladders and am very glad I don't have to deal with it, it makes observing much more pleasurable. I agree with Erik, 10x per inch is about the optimum magnification for most telescopes in my experience, reflectors anyway, and I find myself drifting back to that magnification after going to higher or lower powers. I've had a total of 3 reflectors and would use the 10x magnification the most with each. I might say that for a good refractor the optimum might be a bit higher than 10x per inch, maybe 15x per inch. Bob ------------------------------ Message: 5 Date: Wed, 7 Jan 2009 17:53:04 -0700 From: "Chuck Hards" <chuck.hards(a)gmail.com> Subject: Re: [Utah-astronomy] 13.1 inch Coulter Carcass, free To: "Utah Astronomy" <utah-astronomy(a)mailman.xmission.com> Message-ID: <2541d8030901071653m4de8dbd8vff7c6c0ab9a5f6de(a)mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1 The wrong ladder in the dark can definitely be hazardous, but that's not exactly a problem with a long-focus telescope; it's the wrong choice of ladder. The right choice might not be easily transported, or even easily used at the eyepiece, so that's one of those choices people make. I think the original context of the question was short focal-length mirrors as a first effort at mirror grinding. They do take more work and can be more difficult to figure, but it's not out of reach of the average person, given the proper guidance. If, however, one is purchasing a commercially-made mirror, all the caveats of fabrication can be ignored. I don't agree that deep-sky observing is better at f/4, as a blanket statement. My little RFT is an f/5 and the coma is noticeably less than otherwise identical telescopes I built at f/4, yet the field isn't much smaller using the same eyepiece. I also don't weigh my equipment choices against their fit at a public star party. I'm kind of selfish with my astro-time- my personal enjoyment is my prime motivation. I'll blow-off being "star-party correct" in a heartbeat if I feel I can get some kind of advantage by doing so. On nights when I'm specifically doing the public outreach job, then convenience and safety will trump imagery out of necessity. The telescope must be designed for it's intended use. One person's trade-off list will probably not correspond one-for-one with someone elses. On Wed, Jan 7, 2009 at 1:59 PM, <zaurak(a)digis.net> wrote: > The narrow steps on a ladder can take a toll on your feet in the > course of a night. The classic dobson is long focal length, but there > are many companies that do a good job on fast optics in the 4f range. > Deep sky observing is better with f 4's. > > Tall ladders seem a liability for public star parties. >

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Re: [Utah-astronomy] Utah-Astronomy Digest, Vol 71, Issue 17
by zaurak＠digis.net 07 Jan '09

07 Jan '09

I have always felt 10 power per inch is ideal magnification for most deepsky objects. --- robtaylor3661(a)comcast.net wrote: From: "Robert Taylor" <robtaylor3661(a)comcast.net> To: <utah-astronomy(a)mailman.xmission.com> Subject: Re: [Utah-astronomy] Utah-Astronomy Digest, Vol 71, Issue 17 Date: Wed, 7 Jan 2009 13:22:24 -0700 Nice to hear from you again Jim. I built my 16" as a f/4.45, I was shooting for F/5 but the grind went a little deep and we ended up at 4.45 or 71" (1800 mm). This allows me to stand on my feet nearly all the time and I need about a 6" lift when the scope is straight up, no ladders - ever. This makes the scope a lot easier and faster to use as I never have move a ladder. I understand the benefits of longer focal lengths but in practice the fast f/4.45 works very well and I would not discourage anyone from going that route. Yes you need to use good eyepieces, Naglers work very well. Yes you have to carefully collimate, I sometimes do this twice a night, you get good and fast at it. The grind has to be good but can be done. The 1800m focal length means you have a reasonably wide filed when you need it and it powers up very nicely, remember this is a Dob, how high are you going to go with magnification? As always the best telescope is the one you'll use. Build one that will meet your needs and personal preferences. Bob ************ Message: 1 Date: Wed, 7 Jan 2009 10:04:09 -0800 (PST) From: Jim Gibson <jimgibson00(a)yahoo.com> Subject: Re: [Utah-astronomy] 13.1 inch Coulter Carcass, free To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> Message-ID: <791947.73037.qm(a)web30701.mail.mud.yahoo.com> Content-Type: text/plain; charset=windows-1252 When I took the class from Brent Watson he wanted all of us (about 5 or 6 in the class) to make f8 or better scopes.? Brent loved long bugger scopes and rightfully so I would say.? Someone more qualified than I can tell you all the benefits of a long scope beside increased contras and increased power, but I recall there a lot of benefits?oh yeah collimation is easier too.? Most everyone in our class wanted to make short (fast) scopes mainly because nobody wanted to use a ladders. ? I went with an f7 (the longest focal length in class) so with a 12.5? mirror which would be 87.5? focal length plus some extra I? believe my sono tube was about 96? long. How do you get?96" in the car you ask?? Can you get 48? in your car?? I could deal with 48? so I cut the sono tube down so I had 2 48? sections. I still had sono tube left over because if I remember right it was about 12? long when I bought it. From the extra piece I cut a 1 foot section then slit it down length wise, took some extra material out till I could get it to fit inside one of the 48? sections forming a sleeve. ? ? I went to the hardware store and got some of those clampy thingys like on a metal tool box and put 3 of them on to fasten the 2 scope ?pieces together.? It worked great! ? I have a ladder and a step stool with long hold onto bars, but a lot of the time I use nothing or the step stool.? Yeah, right now I would need the ladder to see M31. ? I love the way my scope performs. I have never been sorry about going f7, but sometimes I do think I should have listened to Brent and gone f8. ? Chuck Hards or someone can tell you stories about Brent fastening his like f10 to the top of his car and having it come off the tope while heading down the freeway?hehe.? The mirror was just fine. ? Brent had a couple of 12.5? f12 or something scopes ?in his hanger where we took the class. ? The good old days. ? jg _______________________________________________ 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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Milky Way Equal to Andromeda
by JayLEads 07 Jan '09

07 Jan '09

Well I was l looking over the news today and found a link to the Harvard-Smithsonian Center for Astrophysics. This is the link: http://www.cfa.harvard.edu/press/2009/pr200903.html The article there states that "astronomers making high-precision measurements of the Milky Way say our Galaxy is rotating about 100,000 miles per hour faster than previously understood." Basically the article states that the increase speed means the mass of the Milky Way is 50 percent greater, which brings the Milky Way even with Andromeda. Their is also an article over at CBS News at http://www.cbsnews.com/stories/2009/01/06/tech/main4700861.shtml? tag=topHome;topStories Mark Reid, the study author states that the Milky Way is no longer the little sister of Andromeda, but the fraternal twin of Andromeda. Also of interest is they now believe the Milky Way has four arms, not just two. Anyway, I found it interesting and though I would share. Enjoy and Clear good skies (sometime?). Jay

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Re: [Utah-astronomy] Utah-Astronomy Digest, Vol 71, Issue 18
by Robert Taylor 07 Jan '09

07 Jan '09

I think cheap telescopes with good optics has taken it's toll on telescope making. Bob Message: 4 Date: Wed, 7 Jan 2009 12:53:56 -0800 From: <zaurak(a)digis.net> Subject: Re: [Utah-astronomy] 13.1 inch Coulter Carcass, free To: "Utah Astronomy" <utah-astronomy(a)mailman.xmission.com> Message-ID: <20090107125356.A97D6D63(a)resin09.mta.everyone.net> Content-Type: text/plain; charset="UTF-8" dinosaur carcass to boot. Seriously SLAS used to have a good number of people building telescopes. What happened to that? I wonder if Amateur Telescope Making is on the decline. Erik

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Re: [Utah-astronomy] 13.1 inch Coulter Carcass, free
by zaurak＠digis.net 07 Jan '09

07 Jan '09

The narrow steps on a ladder can take a toll on your feet in the course of a night. The classic dobson is long focal length, but there are many companies that do a good job on fast optics in the 4f range. Deep sky observing is better with f 4's. Tall ladders seem a liability for public star parties. Erik --- jimgibson00(a)yahoo.com wrote: From: Jim Gibson <jimgibson00(a)yahoo.com> To: Utah Astronomy <utah-astronomy(a)mailman.xmission.com> Subject: Re: [Utah-astronomy] 13.1 inch Coulter Carcass, free Date: Wed, 7 Jan 2009 10:04:09 -0800 (PST) When I took the class from Brent Watson he wanted all of us (about 5 or 6 in the class) to make f8 or better scopes. Brent loved long bugger scopes and rightfully so I would say. Someone more qualified than I can tell you all the benefits of a long scope beside increased contras and increased power, but I recall there a lot of benefits…oh yeah collimation is easier too. Most everyone in our class wanted to make short (fast) scopes mainly because nobody wanted to use a ladders. I went with an f7 (the longest focal length in class) so with a 12.5” mirror which would be 87.5” focal length plus some extra I believe my sono tube was about 96” long. How do you get 96" in the car you ask? Can you get 48” in your car? I could deal with 48” so I cut the sono tube down so I had 2 48” sections. I still had sono tube left over because if I remember right it was about 12’ long when I bought it. From the extra piece I cut a 1 foot section then slit it down length wise, took some extra material out till I could get it to fit inside one of the 48” sections forming a sleeve. I went to the hardware store and got some of those clampy thingys like on a metal tool box and put 3 of them on to fasten the 2 scope pieces together. It worked great! I have a ladder and a step stool with long hold onto bars, but a lot of the time I use nothing or the step stool. Yeah, right now I would need the ladder to see M31. I love the way my scope performs. I have never been sorry about going f7, but sometimes I do think I should have listened to Brent and gone f8. Chuck Hards or someone can tell you stories about Brent fastening his like f10 to the top of his car and having it come off the tope while heading down the freeway…hehe. The mirror was just fine. Brent had a couple of 12.5” f12 or something scopes in his hanger where we took the class. The good old days. jg --- On Wed, 1/7/09, Tyler Allred <tylerallred(a)earthlink.net> wrote: From: Tyler Allred <tylerallred(a)earthlink.net> Subject: Re: [Utah-astronomy] 13.1 inch Coulter Carcass, free To: "'Utah Astronomy'" <utah-astronomy(a)mailman.xmission.com> Date: Wednesday, January 7, 2009, 10:17 AM Warning--- Please don't take this toungue-in-cheek comment the wrong way. WOW! Who would have thought that an offer of a "dismembered carcass" would generate so much discussion? I love this list! :) Tyler _____________________________________________ _______________________________________________ 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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Re: [Utah-astronomy] Bird on Io
by zaurak＠digis.net 07 Jan '09

07 Jan '09

Don't we have one of those at Quantico and Twenty Nine Palms? --- David.Dunn(a)supervalu.com wrote: From: "Dunn, David" <David.Dunn(a)supervalu.com> To: "Utah Astronomy" <utah-astronomy(a)mailman.xmission.com> Subject: [Utah-astronomy] Bird on Io Date: Wed, 7 Jan 2009 12:51:07 -0700 I just read an article from the AP that seems to say that there is a bird living on Io. The article is about Bush designating some Marine Sanctuaries. Quote: Each location in the new national marine monuments harbors unique species and some of the rarest geological formations on Earth, including a bird that incubates its eggs in the heat of underwater volcanoes and a sulfur pool - the only other one exists on Jupiter's moon Io. Dave _______________________________________________ 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] 13.1 inch Coulter Carcass, free
by zaurak＠digis.net 07 Jan '09

07 Jan '09

dinosaur carcass to boot. Seriously SLAS used to have a good number of people building telescopes. What happened to that? I wonder if Amateur Telescope Making is on the decline. Erik --- tylerallred(a)earthlink.net wrote: From: "Tyler Allred" <tylerallred(a)earthlink.net> To: "'Utah Astronomy'" <utah-astronomy(a)mailman.xmission.com> Subject: Re: [Utah-astronomy] 13.1 inch Coulter Carcass, free Date: Wed, 7 Jan 2009 10:17:18 -0700 Warning--- Please don't take this toungue-in-cheek comment the wrong way. WOW! Who would have thought that an offer of a "dismembered carcass" would generate so much discussion? I love this list! :) Tyler _____________________________________________ _______________________________________________ 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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Bird on Io
by Dunn, David 07 Jan '09

07 Jan '09

I just read an article from the AP that seems to say that there is a bird living on Io. The article is about Bush designating some Marine Sanctuaries. Quote: Each location in the new national marine monuments harbors unique species and some of the rarest geological formations on Earth, including a bird that incubates its eggs in the heat of underwater volcanoes and a sulfur pool - the only other one exists on Jupiter's moon Io. Dave

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