Kim, have you tried a Hartmann mask? -----Original Message----- From: Kim Hyatt <kimharch@cut.net> Sent: Jun 29, 2005 3:36 PM To: Utah Astronomy <utah-astronomy@mailman.xmission.com> Subject: [Utah-astronomy] nothing serious BlankHi all. Some of you know that I recently moved to Mt. Pleasant (and many of you probably don't care). I have a home a few miles east of town, with very DARK skies and great views of the valley and mountains. Our elevation here is about 6400 feet and there's very little light pollution, even from Mt. Pleasant itself, just three miles away. Hope some of you may be interested in visiting sometime. I've been experimenting with my Nikon D70 and I've captured some successful wide-angle images. Shortly I'll post them to the gallery. I have also recently tried some prime-focus pics, but I have trouble getting the focus correct. Anyone out there know some cool trick to focus accurately with a digital SLR? Keep in mind that you can't remove the camera back for a knife-edge focus. I also may try imaging with my 8-inch SCT, so tips would be helpful. Hope to rendezvous with y'all sometime. How about a star party at the old Skyline Drive site? Also, is Wolf Creek the pick for July's SLAS private star party? Kim A. Hyatt, Architect P.O. Box 124 Mt. Pleasant, Utah 84647 T: 435.462.9207 F: 435/462.5013 M: 801.631.5228 kimharch@cut.net
I was going to ask, "What is a Hartmann mask?" but then I saw Rob's post. (Thanks Rob - great pics, too.) I still have a couple of questions: Does hole size matter? Distance from center? Distance of mask from refractor objective, or SCT corrector plate? Oh, and thanks for the help all. ----- Original Message ----- From: "Michael Carnes" <michaelcarnes@earthlink.net> To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Sent: Wednesday, June 29, 2005 4:23 PM Subject: Re: [Utah-astronomy] nothing serious | Kim, have you tried a Hartmann mask? | | -----Original Message----- | From: Kim Hyatt <kimharch@cut.net> | Sent: Jun 29, 2005 3:36 PM | To: Utah Astronomy <utah-astronomy@mailman.xmission.com> | Subject: [Utah-astronomy] nothing serious | | BlankHi all. Some of you know that I recently moved to Mt. Pleasant (and many of you probably don't care). I have a home a few miles east of town, with very DARK skies and great views of the valley and mountains. Our elevation here is about 6400 feet and there's very little light pollution, even from Mt. Pleasant itself, just three miles away. Hope some of you may be interested in visiting sometime. | | I've been experimenting with my Nikon D70 and I've captured some successful wide-angle images. Shortly I'll post them to the gallery. I have also recently tried some prime-focus pics, but I have trouble getting the focus correct. Anyone out there know some cool trick to focus accurately with a digital SLR? Keep in mind that you can't remove the camera back for a knife-edge focus. I also may try imaging with my 8-inch SCT, so tips would be helpful. | | Hope to rendezvous with y'all sometime. How about a star party at the old Skyline Drive site? Also, is Wolf Creek the pick for July's SLAS private star party? | | | Kim A. Hyatt, Architect | P.O. Box 124 | Mt. Pleasant, Utah 84647 | T: 435.462.9207 | F: 435/462.5013 | M: 801.631.5228 | kimharch@cut.net | | | | | _______________________________________________ | Utah-Astronomy mailing list | Utah-Astronomy@mailman.xmission.com | http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy | Visit the Photo Gallery: http://www.utahastronomy.com | | ______________________________________________________________________ | This e-mail has been scanned by Cut.Net Managed Email Content Service, using Skeptic(tm) technology powered by MessageLabs. For more information on Cut.Nets Content Service, visit http://www.cut.net | ______________________________________________________________________ | |
Oops - Rob's email was to me, personally. Sorry to all. Rob described the Hartmann mask for me, "cardboard disc same size as OTA w/ 3 evenly spaced holes, placed over the front, focus till all 'holes' align." I think that I "get it" generally, but my questions posted earlier still apply. ----- Original Message ----- From: "Kim Hyatt" <kimharch@cut.net> To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Sent: Wednesday, June 29, 2005 5:00 PM Subject: Re: [Utah-astronomy] nothing serious |I was going to ask, "What is a Hartmann mask?" but then I saw Rob's post. | (Thanks Rob - great pics, too.) I still have a couple of questions: Does | hole size matter? Distance from center? Distance of mask from refractor | objective, or SCT corrector plate? | | Oh, and thanks for the help all. | | | ----- Original Message ----- | From: "Michael Carnes" <michaelcarnes@earthlink.net> | To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> | Sent: Wednesday, June 29, 2005 4:23 PM | Subject: Re: [Utah-astronomy] nothing serious | | || Kim, have you tried a Hartmann mask? || || -----Original Message----- || From: Kim Hyatt <kimharch@cut.net> || Sent: Jun 29, 2005 3:36 PM || To: Utah Astronomy <utah-astronomy@mailman.xmission.com> || Subject: [Utah-astronomy] nothing serious || || BlankHi all. Some of you know that I recently moved to Mt. Pleasant (and | many of you probably don't care). I have a home a few miles east of town, | with very DARK skies and great views of the valley and mountains. Our | elevation here is about 6400 feet and there's very little light pollution, | even from Mt. Pleasant itself, just three miles away. Hope some of you may | be interested in visiting sometime. || || I've been experimenting with my Nikon D70 and I've captured some | successful wide-angle images. Shortly I'll post them to the gallery. I have | also recently tried some prime-focus pics, but I have trouble getting the | focus correct. Anyone out there know some cool trick to focus accurately | with a digital SLR? Keep in mind that you can't remove the camera back for a | knife-edge focus. I also may try imaging with my 8-inch SCT, so tips would | be helpful. || || Hope to rendezvous with y'all sometime. How about a star party at the old | Skyline Drive site? Also, is Wolf Creek the pick for July's SLAS private | star party? || || || Kim A. Hyatt, Architect || P.O. Box 124 || Mt. Pleasant, Utah 84647 || T: 435.462.9207 || F: 435/462.5013 || M: 801.631.5228 || kimharch@cut.net || || || || || _______________________________________________ || Utah-Astronomy mailing list || Utah-Astronomy@mailman.xmission.com || http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy || Visit the Photo Gallery: http://www.utahastronomy.com || || ______________________________________________________________________ || This e-mail has been scanned by Cut.Net Managed Email Content Service, | using Skeptic(tm) technology powered by MessageLabs. For more information on | Cut.Nets Content Service, visit http://www.cut.net || ______________________________________________________________________ || || | | | | _______________________________________________ | Utah-Astronomy mailing list | Utah-Astronomy@mailman.xmission.com | http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy | Visit the Photo Gallery: http://www.utahastronomy.com | | ______________________________________________________________________ | This e-mail has been scanned by Cut.Net Managed Email Content Service, using Skeptic(tm) technology powered by MessageLabs. For more information on Cut.Nets Content Service, visit http://www.cut.net | ______________________________________________________________________ | | ______________________________________________________________________ | This e-mail has been scanned by Cut.Net Managed Email Content Service, using Skeptic(tm) technology powered by MessageLabs. For more information on Cut.Nets Content Service, visit http://www.cut.net | ______________________________________________________________________ | |
Hi Kim: Last time we spoke, you were considering moving in the next 'year or two', what moved-up the timetable? Is the rural location everything you hoped-for? I still have a model kit for you! The number of holes in the mask isn't critical. Two holes, diametrically opposed, are sufficient. C. --- Kim Hyatt <kimharch@cut.net> wrote:
Oops - Rob's email was to me, personally. Sorry to all.
Rob described the Hartmann mask for me, "cardboard disc same size as OTA w/ 3 evenly spaced holes, placed over the front, focus till all 'holes' align." I think that I "get it" generally, but my questions posted earlier still apply.
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--- Kim Hyatt <kimharch@cut.net> wrote: <snip>
Rob described the Hartmann mask for me, "cardboard disc same size as OTA w/ 3 evenly spaced holes, placed over the front . . .
My camera Hartmann mask looks like this - it's not very precise - http://www.astropix.com/HTML/I_ASTROP/I08/I0817/I0817.HTM See also Reeves trick of using a bright wide-double to focus using the Hartmann mask and a star trail exposure. http://www.astrofoto.org/tips/focus/ You can also use a magnifier. Nikon makes (made) a proprietary magnifier. I use a hand-loupe per Lodriguss - http://www.astropix.com/HTML/I_ASTROP/TOC_AP.HTM More difficult is the star trail test - I haven't done this one - http://www.astropix.com/HTML/I_ASTROP/I08/I0818/I0818.HTM See Jerry Lodriguss's focusing pages - http://www.astropix.com/HTML/I_ASTROP/I08/I0812/I0812.HTM Enjoy - Canopus56 (Kurt) ____________________________________________________ Yahoo! Sports Rekindle the Rivalries. Sign up for Fantasy Football http://football.fantasysports.yahoo.com
Mahalo Kurt for all the good sites to check focus. Aloha Rob
--- Rob Ratkowski <ratkwski@hawaii.rr.com> wrote:
Mahalo Kurt for all the good sites to check focus.
Aloha kâua astro - back at you. It wasn't clear to me whether Kim was talking about focusing his camera piggyback on the telescope or coupling the camera to the telescope. If so, then we're also talking digital fine tuning the focus using FWHM. I have less experience with that. - Kurt ____________________________________________________ Yahoo! Sports Rekindle the Rivalries. Sign up for Fantasy Football http://football.fantasysports.yahoo.com
Hi Kurt I think Kim was talking about focusing the camera while at prime focus, tough w/o any help. The Hartmann mask works great and is easy to construct and the there are the programs ............ aloha from Maui Rob
I have no problem focusing piggyback - my lens is accurate enough at infinity. I asked about focusing at prime focus (camer mounted to telescope as eyepiece). But, I have to admit my ignorance...again...what's FWHM? ----- Original Message ----- From: "Canopus56" <canopus56@yahoo.com> To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Sent: Wednesday, June 29, 2005 6:39 PM Subject: Re: [Utah-astronomy] nothing serious | --- Rob Ratkowski <ratkwski@hawaii.rr.com> wrote: | > Mahalo Kurt for all the good sites to check focus. | | Aloha kâua astro - back at you. It wasn't clear to me | whether Kim was talking about focusing his camera | piggyback on the telescope or coupling the camera to | the telescope. If so, then we're also talking digital | fine tuning the focus using FWHM. I have less | experience with that. | | - Kurt | | | | | ____________________________________________________ | Yahoo! Sports | Rekindle the Rivalries. Sign up for Fantasy Football | http://football.fantasysports.yahoo.com | | _______________________________________________ | Utah-Astronomy mailing list | Utah-Astronomy@mailman.xmission.com | http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy | Visit the Photo Gallery: http://www.utahastronomy.com | | ______________________________________________________________________ | This e-mail has been scanned by Cut.Net Managed Email Content Service, using Skeptic(tm) technology powered by MessageLabs. For more information on Cut.Nets Content Service, visit http://www.cut.net | ______________________________________________________________________ | |
Kim You probably can find some DIY info http://www.cloudynights.com/howtos2/hartman/hartman.htm http://www.google.com/search?biw=769&hl=en&ie=ISO-8859-1&q=Hartmann+mask) on line. Almost any size (w/i reason) hole works spaced 120 apart. Small holes for bright objects, somewhat larger holes for dim objects. I do believe there are some Hartmann masks commercially available also Have fun Rob
participants (5)
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Canopus56 -
Chuck Hards -
Kim Hyatt -
Michael Carnes -
Rob Ratkowski