Chuck Hards was kind enough to offer to make a custom fitted white-light solar filter for SPOC's Bogdan refractor so I brought that up at last evening's SLAS board meeting. There was some discussion about whether any such filter should be make of mylar or glass (to be determined) but one thing that I'd like discussed here is the size of the filter itself. Usually when it comes to telescopes I think "bigger is better" but in this case I'm wondering if it would be better to go full aperture (200mm) or would we really gain that much by going full aperture over something smaller. Opinions? patrick
Patrick,
From my experience, you get finer resolution with the full aperture. I have no problem in using a Baader film filter on the refractor as long as the filter is carefully inspected before each use.
Thanks Rodger C. Fry -----Original Message----- From: utah-astronomy-bounces@mailman.xmission.com [mailto:utah-astronomy-bounces@mailman.xmission.com] On Behalf Of Patrick Wiggins Sent: Friday, March 15, 2013 3:39 AM To: utah astronomy listserve utah astronomy Subject: [Utah-astronomy] Sun viewing question Chuck Hards was kind enough to offer to make a custom fitted white-light solar filter for SPOC's Bogdan refractor so I brought that up at last evening's SLAS board meeting. There was some discussion about whether any such filter should be make of mylar or glass (to be determined) but one thing that I'd like discussed here is the size of the filter itself. Usually when it comes to telescopes I think "bigger is better" but in this case I'm wondering if it would be better to go full aperture (200mm) or would we really gain that much by going full aperture over something smaller. Opinions? patrick _______________________________________________ Utah-Astronomy mailing list http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Send messages to the list to Utah-Astronomy@mailman.xmission.com The Utah-Astronomy mailing list is not affiliated with any astronomy club. To unsubscribe go to: http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Then enter your email address in the space provided and click on "Unsubscribe or edit options".
Make it a printed, hard and fast rule, Rodger. That rule should apply to optical glass solar filters as well. The coating is evaporated metal, just as thin and delicate as that on any first-surface mirror. On Fri, Mar 15, 2013 at 8:20 AM, Rodger C. Fry <rcfry@comcast.net> wrote:
Patrick,
From my experience, you get finer resolution with the full aperture. I have no problem in using a Baader film filter on the refractor as long as the filter is carefully inspected before each use.
On Fri, Mar 15, 2013 at 3:39 AM, Patrick Wiggins <paw@wirelessbeehive.com>wrote:
Chuck Hards was kind enough to offer to make a custom fitted white-light solar filter for SPOC's Bogdan refractor so I brought that up at last evening's SLAS board meeting.
There was some discussion about whether any such filter should be make of mylar or glass (to be determined) but one thing that I'd like discussed here is the size of the filter itself.
Usually when it comes to telescopes I think "bigger is better" but in this case I'm wondering if it would be better to go full aperture (200mm) or would we really gain that much by going full aperture over something smaller.
Opinions?
Patrick, I was thinking about the aperture question, myself.
Mornings are usually the best time for large, full-aperture solar viewing. By afternoon, daytime seeing almost always degrades to the point where large apertures don't result in increased resolution. Also, 5 or 6 inches of aperture is usually enough for high-powered views of small solar detail. So I would recommend a solar filter of about 6 inches for the Bogdan refractor, but I could easily make it full-aperture if desired. As to mylar vs. glass, my offer is for a Baader filter only. If the board wants a glass filter, they will have to purchase a commercial one using SPOC funds, or have one donated by someone else. I own both types. I use Thousand Oaks glass as well as Celestron glass, but I prefer the Baader filter material. The sun is "white" to our eyes, and only the Baader filter is a true "neutral" density filter. I consistently see finer detail with the Baader filter than through the orange-tinted glass filters (or any color glass filter, for that matter). Baader solar film is the best made, is true optical-quality mylar, and is 100% safe. I know some people don't like mylar but it's come a long way since Tuthill's "Solar Skreen"- which was utter crap, no offense intended to the late Mr. Tuthill. It also lasts a long time if properly taken care-of. I just replaced the mylar on one of my filter cells that was 15 years old. Glass filters with their evaporated metal coatings are delicate too. If dropped, they shatter, and are just as susceptible to pinholes in the coating. If damaged, you buy a whole new filter and have to wait for it. A Baader filter can be replaced the same day. I'll even donate an extra piece of filter material that can be kept in a large envelope in the SPOC equipment bay, and will show the telescope operators how to replace it in the field if it's ever necessary. I have to laugh when people state that an orange-tinted sun looks more natural. They are responding to a lifetime of conditioning, from art and photographs taken through tinted filters. We evolved under sunlight and to our eyes, the sun is most definitely "white", or neutral in tint, spectral classification aside. If the board wants to take me up on my offer, I will also make a filter for the refractor's finder.
Hi Chuck, Too bad you could not have been at the meeting. I brought up your offer and was surprised at the negative reception the idea of using non-glass filters received. You could have set them straight. :) Rodger Fry and I would be happy with a full aperture Baader. Rodger is e boss so his vote wins. I'll be at SPOC this evening so while there I'll get some measurements and pass them on to you. Thanks again, patrick
The best views I have had of the sun is with a 50mm scope and 90mm scope. I think the issue is you have to come have something that people cannot damage. The H-alpha is good example, if you make it widely available it has to be done with an optical system that will not damage it. Personal and group use are 2 different animals.
Hi Chuck,
Too bad you could not have been at the meeting. I brought up your offer and was surprised at the negative reception the idea of using non-glass filters received. You could have set them straight. :)
Rodger Fry and I would be happy with a full aperture Baader. Rodger is e boss so his vote wins.
I'll be at SPOC this evening so while there I'll get some measurements and pass them on to you.
Thanks again,
patrick _______________________________________________ Utah-Astronomy mailing list http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy
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People can damage anything. There is no such thing as "damage proof" optical equipment. I'll address the subject of club-owned solar equipment more fully tomorrow. I'm beat. Worked all day in the yard. Feels good. Good night folks! On Mar 15, 2013 3:50 PM, <erikhansen@thebluezone.net> wrote:
The best views I have had of the sun is with a 50mm scope and 90mm scope. I think the issue is you have to come have something that people cannot damage. The H-alpha is good example, if you make it widely available it has to be done with an optical system that will not damage it. Personal and group use are 2 different animals.
Hi Chuck,
Too bad you could not have been at the meeting. I brought up your offer and was surprised at the negative reception the idea of using non-glass filters received. You could have set them straight. :)
Rodger Fry and I would be happy with a full aperture Baader. Rodger is e boss so his vote wins.
I'll be at SPOC this evening so while there I'll get some measurements
and
pass them on to you.
Thanks again,
patrick _______________________________________________ Utah-Astronomy mailing list http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy
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_______________________________________________ Utah-Astronomy mailing list http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy
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You can take steps to minimize the chances of damage.
People can damage anything. There is no such thing as "damage proof"
optical equipment. I'll address the subject of club-owned solar equipment more fully tomorrow.
I'm beat. Worked all day in the yard. Feels good.
Good night folks! On Mar 15, 2013 3:50 PM, <erikhansen@thebluezone.net> wrote:
The best views I have had of the sun is with a 50mm scope and 90mm scope. I think the issue is you have to come have something that people cannot damage. The H-alpha is good example, if you make it widely available it has to be done with an optical system that will not damage it. Personal and group use are 2 different animals.
Hi Chuck,
Too bad you could not have been at the meeting. I brought up your
offer
and was surprised at the negative reception the idea of using non-glass filters received. You could have set them straight. :)
Rodger Fry and I would be happy with a full aperture Baader. Rodger is e boss so his vote wins.
I'll be at SPOC this evening so while there I'll get some measurements and pass them on to you.
Thanks again,
patrick _______________________________________________ Utah-Astronomy mailing list http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy
Send messages to the list to Utah-Astronomy@mailman.xmission.com
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_______________________________________________ Utah-Astronomy mailing list http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy
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Hi Chuck, Looks like most are saying to go full aperture so please do that if possible. I went over to SPOC last evening and took a picture and got some measurements. Taking the picture got me a good look at the objective and reminded me that it really needs to be cleaned. http://users.wirelessbeehive.com/~paw/temp/BOGDAN.JPG The diameter of the glass is 200mm. The outside diameter of the cell is 250mm. That, BTW, surprised me as I machined the cell to fit the piece of irrigation pipe that now serves as the scope's dew shield. I figured that since I bought the pipe here in Utah it would have been manufactured in American units. But, no, it's exactly 250mm. Speaking of American units, anyone care to guess the significance of this display of American units (image taken in my truck yesterday)? http://users.wirelessbeehive.com/~paw/temp/almost20.JPG But back to the filter, thanks for doing that Chuck. Much appreciated. patrick On 15 Mar 2013, at 08:21, Chuck Hards wrote:
On Fri, Mar 15, 2013 at 3:39 AM, Patrick Wiggins <paw@wirelessbeehive.com>wrote:
Chuck Hards was kind enough to offer to make a custom fitted white-light solar filter for SPOC's Bogdan refractor so I brought that up at last evening's SLAS board meeting.
There was some discussion about whether any such filter should be make of mylar or glass (to be determined) but one thing that I'd like discussed here is the size of the filter itself.
Usually when it comes to telescopes I think "bigger is better" but in this case I'm wondering if it would be better to go full aperture (200mm) or would we really gain that much by going full aperture over something smaller.
Opinions?
Patrick, I was thinking about the aperture question, myself.
Mornings are usually the best time for large, full-aperture solar viewing. By afternoon, daytime seeing almost always degrades to the point where large apertures don't result in increased resolution. Also, 5 or 6 inches of aperture is usually enough for high-powered views of small solar detail. So I would recommend a solar filter of about 6 inches for the Bogdan refractor, but I could easily make it full-aperture if desired.
As to mylar vs. glass, my offer is for a Baader filter only. If the board wants a glass filter, they will have to purchase a commercial one using SPOC funds, or have one donated by someone else.
I own both types. I use Thousand Oaks glass as well as Celestron glass, but I prefer the Baader filter material. The sun is "white" to our eyes, and only the Baader filter is a true "neutral" density filter. I consistently see finer detail with the Baader filter than through the orange-tinted glass filters (or any color glass filter, for that matter). Baader solar film is the best made, is true optical-quality mylar, and is 100% safe. I know some people don't like mylar but it's come a long way since Tuthill's "Solar Skreen"- which was utter crap, no offense intended to the late Mr. Tuthill. It also lasts a long time if properly taken care-of. I just replaced the mylar on one of my filter cells that was 15 years old. Glass filters with their evaporated metal coatings are delicate too. If dropped, they shatter, and are just as susceptible to pinholes in the coating. If damaged, you buy a whole new filter and have to wait for it. A Baader filter can be replaced the same day. I'll even donate an extra piece of filter material that can be kept in a large envelope in the SPOC equipment bay, and will show the telescope operators how to replace it in the field if it's ever necessary.
I have to laugh when people state that an orange-tinted sun looks more natural. They are responding to a lifetime of conditioning, from art and photographs taken through tinted filters. We evolved under sunlight and to our eyes, the sun is most definitely "white", or neutral in tint, spectral classification aside.
If the board wants to take me up on my offer, I will also make a filter for the refractor's finder.
That truck has been around the world - more than 6 times. ________________________________ From: Patrick Wiggins <paw@wirelessbeehive.com> To: Utah Astronomy <utah-astronomy@mailman.xmission.com> Sent: Saturday, March 16, 2013 1:04 AM Subject: [Utah-astronomy] Bogdan solar filter Hi Chuck, Looks like most are saying to go full aperture so please do that if possible. I went over to SPOC last evening and took a picture and got some measurements. Taking the picture got me a good look at the objective and reminded me that it really needs to be cleaned. http://users.wirelessbeehive.com/~paw/temp/BOGDAN.JPG The diameter of the glass is 200mm. The outside diameter of the cell is 250mm. That, BTW, surprised me as I machined the cell to fit the piece of irrigation pipe that now serves as the scope's dew shield. I figured that since I bought the pipe here in Utah it would have been manufactured in American units. But, no, it's exactly 250mm. Speaking of American units, anyone care to guess the significance of this display of American units (image taken in my truck yesterday)? http://users.wirelessbeehive.com/~paw/temp/almost20.JPG But back to the filter, thanks for doing that Chuck. Much appreciated. patrick On 15 Mar 2013, at 08:21, Chuck Hards wrote:
On Fri, Mar 15, 2013 at 3:39 AM, Patrick Wiggins <paw@wirelessbeehive.com>wrote:
Chuck Hards was kind enough to offer to make a custom fitted white-light solar filter for SPOC's Bogdan refractor so I brought that up at last evening's SLAS board meeting.
There was some discussion about whether any such filter should be make of mylar or glass (to be determined) but one thing that I'd like discussed here is the size of the filter itself.
Usually when it comes to telescopes I think "bigger is better" but in this case I'm wondering if it would be better to go full aperture (200mm) or would we really gain that much by going full aperture over something smaller.
Opinions?
Patrick, I was thinking about the aperture question, myself.
Mornings are usually the best time for large, full-aperture solar viewing. By afternoon, daytime seeing almost always degrades to the point where large apertures don't result in increased resolution. Also, 5 or 6 inches of aperture is usually enough for high-powered views of small solar detail. So I would recommend a solar filter of about 6 inches for the Bogdan refractor, but I could easily make it full-aperture if desired.
As to mylar vs. glass, my offer is for a Baader filter only. If the board wants a glass filter, they will have to purchase a commercial one using SPOC funds, or have one donated by someone else.
I own both types. I use Thousand Oaks glass as well as Celestron glass, but I prefer the Baader filter material. The sun is "white" to our eyes, and only the Baader filter is a true "neutral" density filter. I consistently see finer detail with the Baader filter than through the orange-tinted glass filters (or any color glass filter, for that matter). Baader solar film is the best made, is true optical-quality mylar, and is 100% safe. I know some people don't like mylar but it's come a long way since Tuthill's "Solar Skreen"- which was utter crap, no offense intended to the late Mr. Tuthill. It also lasts a long time if properly taken care-of. I just replaced the mylar on one of my filter cells that was 15 years old. Glass filters with their evaporated metal coatings are delicate too. If dropped, they shatter, and are just as susceptible to pinholes in the coating. If damaged, you buy a whole new filter and have to wait for it. A Baader filter can be replaced the same day. I'll even donate an extra piece of filter material that can be kept in a large envelope in the SPOC equipment bay, and will show the telescope operators how to replace it in the field if it's ever necessary.
I have to laugh when people state that an orange-tinted sun looks more natural. They are responding to a lifetime of conditioning, from art and photographs taken through tinted filters. We evolved under sunlight and to our eyes, the sun is most definitely "white", or neutral in tint, spectral classification aside.
If the board wants to take me up on my offer, I will also make a filter for the refractor's finder.
_______________________________________________ Utah-Astronomy mailing list http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Send messages to the list to Utah-Astronomy@mailman.xmission.com The Utah-Astronomy mailing list is not affiliated with any astronomy club. To unsubscribe go to: http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Then enter your email address in the space provided and click on "Unsubscribe or edit options".
Or to the Moon and part way back. Actually the original plan had been to take the image right at 310,685.6 but I forgot until 20 past that. patrick On 16 Mar 2013, at 13:39, Brent Watson wrote:
That truck has been around the world - more than 6 times.
________________________________ From: Patrick Wiggins <paw@wirelessbeehive.com> To: Utah Astronomy <utah-astronomy@mailman.xmission.com> Sent: Saturday, March 16, 2013 1:04 AM Subject: [Utah-astronomy] Bogdan solar filter
snip
Speaking of American units, anyone care to guess the significance of this display of American units (image taken in my truck yesterday)?
Bigger is still better. On Fri, Mar 15, 2013 at 3:39 AM, Patrick Wiggins <paw@wirelessbeehive.com>wrote:
Chuck Hards was kind enough to offer to make a custom fitted white-light solar filter for SPOC's Bogdan refractor so I brought that up at last evening's SLAS board meeting.
There was some discussion about whether any such filter should be make of mylar or glass (to be determined) but one thing that I'd like discussed here is the size of the filter itself.
Usually when it comes to telescopes I think "bigger is better" but in this case I'm wondering if it would be better to go full aperture (200mm) or would we really gain that much by going full aperture over something smaller.
Opinions?
patrick _______________________________________________ Utah-Astronomy mailing list http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy
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-- Siegfried
participants (6)
-
Brent Watson -
Chuck Hards -
erikhansen＠thebluezone.net -
Patrick Wiggins -
Rodger C. Fry -
Siegfried Jachmann