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

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

07 Jan '09

I would not want to discourage anyone from grinding own mirror, but as I recall the 13.1 Coulter was an f 4.5, maybe to fast for first attempt. The Coulter mirror was outstanding, the tube assembly not so much. I think someone recommended using it for a planter. I would also recommend thinking long and hard about where the focuser will be place for comfortable viewing. I have come to the conclusion that a 16" f5 would be my ideal. I would also not recommend building a large scope with another person. Make out a written contract if you do. 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 03:51:27 -0800 (PST) Jay, If Brent Watson was still around he could probably tell you exactly, but I think Chuck’s amount was probably about right. I took a class from Brent about 6 – 7 years ago and as I remember it cost like $350 - $400 for the mirror kit, another couple hundred for the Craford (sp?) focuser, $75 - $100 for either the 1/4th or 1/8th wave secondary, and of course you will need at least 1 lens. But lenses are like potato chips; you can’t eat just one. We started our class in January and ordered our stuff. I got a 12.5” mirror. It took a few weeks for delivery and came with all the materials for grinding accept the grinding wheel which we made ourselves. We ground our mirrors one night a week (7 -10 pm) under Brent’s tutelage and finished our mirror and scopes, which we built at home (Carcass part), by May. Oh yeah we also made our own Ronchi (sp?) tester which you need to complete the figuring of the mirror. I kept copious notes, but like most things, there are stored away in a box somewhere…lol. I guess my point is, if you have never made a mirror before, don’t do it alone. The other point is that making your own is a very rewarding experience. If it costs you about the same either way, making a scope at least once in your armature career, I think, is very worth it. But you need the right guidance. jg --- On Tue, 1/6/09, Jay Eads <jayleads(a)gmail.com> wrote: From: Jay Eads <jayleads(a)gmail.com> Subject: Re: [Utah-astronomy] 13.1 inch Coulter Carcass, free To: "Utah-Astronomy" <utah-astronomy(a)mailman.xmission.com> Date: Tuesday, January 6, 2009, 7:47 PM How hard and how long would it take to make the mirror (yes, I'm attending the SLAS meeting this month) for someone who hasn't done it before? What would the estimated cost be for the materials for the mirror? Is there anyone here or in SLAS who would be available for advice? I'm interested in making my own mirror but it depends on cost (you know, the wife/CFO). If all these add up I'd take the dob tube and the rocker box. I would assume the first step would be to make the primary mirror, then to get a secondary and a focuser. So I guess if this is a project that I can assemble over time as money comes up, I'd try it. Thanks, Jay On 2009-01-06 22:56, Patrick Wiggins wrote: > I understand the "how to make a mirror" video that we were not able to > screen at the solstice party last month is going to be shown at this > month's SLAS meeting. > > Perhaps after watching that several people will want the carcass to > use with their new homemade mirror. > > Grins, > > patrick > > > On 06 Jan 2009, at 09:48, Josephine Grahn wrote: > > > We have the empty carcass of a 13.1 inch blue Coulter dob, if anyone > > would like it. No optics, no focuser, just the empty tube and rocker > > box. It does have the mirror cell, but no primary mirror, and it does > > have the support for the secondary, but no secondary mirror. Free, > > you just have to pick it up. Located East side SLC. > > _______________________________________________ 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] Utah-Astronomy Digest, Vol 71, Issue 17
by Robert Taylor 07 Jan '09

07 Jan '09

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

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

07 Jan '09

How hard and how long would it take to make the mirror (yes, I'm attending the SLAS meeting this month) for someone who hasn't done it before? What would the estimated cost be for the materials for the mirror? Is there anyone here or in SLAS who would be available for advice? I'm interested in making my own mirror but it depends on cost (you know, the wife/CFO). If all these add up I'd take the dob tube and the rocker box. I would assume the first step would be to make the primary mirror, then to get a secondary and a focuser. So I guess if this is a project that I can assemble over time as money comes up, I'd try it. Thanks, Jay On 2009-01-06 22:56, Patrick Wiggins wrote: > I understand the "how to make a mirror" video that we were not able to > screen at the solstice party last month is going to be shown at this > month's SLAS meeting. > > Perhaps after watching that several people will want the carcass to > use with their new homemade mirror. > > Grins, > > patrick > > > On 06 Jan 2009, at 09:48, Josephine Grahn wrote: > > > We have the empty carcass of a 13.1 inch blue Coulter dob, if anyone > > would like it. No optics, no focuser, just the empty tube and rocker > > box. It does have the mirror cell, but no primary mirror, and it does > > have the support for the secondary, but no secondary mirror. Free, > > you just have to pick it up. Located East side SLC. > >

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Re: [Utah-astronomy] 13.1 inch Coulter Carcass, free
by Jay Eads 06 Jan '09

06 Jan '09

Patrick, sorry I didn't pick up on the joke . . . Chuck, you answered my question. I have the time, I would like to do it, but at a $1000 I know what the wife would say . . . . go buy a 10 or 12 inch pre-made dob after you have the cash and save us some cash, or save up for that new refractor I want. I'll have to pass since we don't have an extra $1000 around . . . an extra $400 I have saving toward another scope, so I'll just keep saving. Sounds like I should place my ambition on getting SPOC certified come April when I'm eligible. I looked at Steve Dodds' Nova Optical and for a 12.5 inch he wants $1000. Though I wouldn't have to worry about shipping since I live in Herriman I think for now I'll just wait to do something like this. Thanks, Jay On 2009-01-07 05:00, Chuck Hards wrote: > On Tue, Jan 6, 2009 at 8:12 PM, Patrick Wiggins <paw@???>wrote: > > > > > And maybe Chuck Hards here on the list (Chuck have you made any > > mirrors recently?). > > > Not recently...not in this century, lol! > > These days, it's not really cost-effective to make a small mirror, but a 13" > home-made mirror could be made at tremendous savings. For example, you can > get finished 8" Chinese mirrors of decent quality for under a hundred bucks, > but a full-thickness (6:1 diameter-to-thickness) 12.5" mirror could run you > a thousand dollars, easily. Larger than that, and some serious cash can be > saved- like the price of a used car! That said, figuring a large diameter, > "thin" mirror isn't generally a good first project, although having said > that, some people have done it and done it well. With all of > the ATM experts in the SLAS and OAS clubs, I'm sure anyone seriously > contemplating grinding their own mirror could easily get all the help they > need. >

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Society for Astronomical Sciences newsletter
by Jerry Foote 06 Jan '09

06 Jan '09

Happy New Year, Everyone! The latest newsletter from the Society for Astronomical Sciences is now available on our web site http://www.SocAstroSci.org Featured are some details about this year's Symposium on Telescope Science, which will be a joint meeting with the AAVSO, so we're expecting a bigger crowd and lots of interesting papers and off-line discussions. Now that the holidays are over and, I hope, things are settling down, I thought I'd add another item to your New Year's resolutions: to start thinking about a paper for the Symposium, to be held May 19-21 in Big Bear, CA. The deadline for abstracts is March 13, 2009. I know, two months away but with the hectic lives we lead, those eight weeks will be come and gone before you know it. Final papers MUST be in by May 3. Please review the newsletter regarding submissions. Things have changed this year. If you have _any_ questions, please let us know at the email given below. Remember that your paper doesn't have to be about some startling new discovery. It can be about work in progress that you're doing in just about any field of interest related to doing astronomy science with your telescope. If you have some results, preliminary or final, we'd be interested to hear about them. Talks about techniques, getting the most out of equipment and/or software, are just as welcome, providing they are of general interest and don't get "too commercial." You'll find an MS Word sample document that has formatting styles and guidelines. If at all possible, please follow this for your final paper so that editing the final proceedings can go smoothly. N.B. The style guide has not been updated yet to follow this year's submission "rules." For one, it talks about how to embed figures into the document. Figures should be sent as separate files, GIF or PNG are preferred for generic plots and figures and JPG for photos. JPG can make line art fuzzy" due to its compression algorithm. If you have any questions, please let us know - sooner than later. You can send an email to the program committee at program_at_socastrosci_dot_org (anti-spam mangled) All abstracts and papers should be sent to that email address to assure that at least one person on the committee receives it. Sending it to a personal email may send it into the black hole of cyberspace. We look forward to seeing you in May and to a great meeting. Jerry Foote ScopeCraft, Inc. 4175 E. Red Cliffs Dr. Kanab, UT 84741 435-899-1255 jfoote(a)scopecraft.com

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Wyorock?
by Chuck Hards 06 Jan '09

06 Jan '09

Anybody know what happened to Wyorock? Their Website is gone.

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2008 hydrazine cloud reference sought
by Canopus56 05 Jan '09

05 Jan '09

I am looking for a reference to a 2008 event where amateurs observed a hydrazine cloud from a satellite. I'm thinking it may have been the USA 193 satellite destruction in Feb. 2008? Any guesses? - Kurt

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First Light Image with ASA N8 - M81 and M82 in Ursa Major
by Tyler Allred 05 Jan '09

05 Jan '09

Hello all. I managed to get everything to work last night and, despite the poor viewing conditions, I got a few frames with the Astro Systeme Austria N8 astrograph that I have been struggling with in recent weeks. Here is a link to the first light image: M81 and M82 in Ursa Major. I choose them because they were bright enough to show through the high haze that seemed to be everywhere last night. This is a combination of 10 3-minute luminance frames, and 3 each 5-minute RGB frames. The camera is also new to me: it is an older Finger Lakes CM-10, which has the same chip as the SBIG ST10 (KAF-3200XME). The camera is very sensitive, which I really like. but it blooms, which is a real pain! I used a new autoguider from Orion through a Borg 60 guide scope, and the guiding setup seems to work well. Everything in this imaging train is new for me, except the old standby Losmandy G-11 mount, which I have had for years. Here is the link: http://71.18.228.62/images/M81LRGB.jpg Be sure to click on the image to view the full sized version. I am pretty happy with this for a first light image, but I am hoping to get the stars much tighter on a better viewing night. Questions, comments and suggestions are always welcome. Happy New Year!! Tyler _____________________________________________

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Meteor Shower
by Rodger C. Fry 04 Jan '09

04 Jan '09

Did anyone get up and see the meteor shower? After the U of U victory, I just went to bed and forgot to set the alarm. Bumber! Thank You, Rodger C. Fry Consulting Geologist

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Gerrish mount
by Chuck Hards 02 Jan '09

02 Jan '09

While going through the basement, putting-away the Christmas decorations, I found an elliptical flat I've had for years, with a 9-inch minor axis. I've thought about using it for an 8" telescope mounted like the 9" Harvard refractor on the "Gerrish" mount. In this type of mount, the optical axis is co-axial with the polar axis and different declinations are observed with a flat mirror in front of the telescope. The telescope is pointed "down", or facing the south celestial pole. This means that, if using a refractor or Cassegrain, the eyepiece remains in a fixed position. It can be on the inside of a heated building, with the flat on the exterior. Only the flat needs to rotate in RA to keep an object centered, but typically the entire optical train is made to rotate with the flat, to make some engineering details a tad easier. Either way works fine. DSC's make finding objects relatively easy, since an optical finder would be quite a complication on this design. Has anyone built such a design? I've seen it in S&T over the years but never a locally made version. S&T even had a 16" Newtonian version featured about 20 years ago, IIRC.

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