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Main
Date: 03 Nov 2006 01:42:39
From: Florian
Subject: Solar eyepiece projection safe for scope?
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I feel i should know the answer to this but the more i think about it =
the more unsure i am. Is it safe to point a Tele Vue 76 at the sun to =
project the image on a white card? (Of course i know it's NEVER safe to =
look directly into the eyepiece of an unfiltered scope.) Is there any =
chance of damage to the internal workings of the scope, like the =
baffles, or to the eyepiece or field stop? I'm planning to take my TV76 =
to work next Wednesday to share the Mercury transit and was thinking to =
project the image on a card. I also have a Baader solar filter so i may =
use both methods. The advantage of the projection method is that many =
people can view at once.
.Florian
Stargazing.com
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Date: 02 Nov 2006 19:57:53
From: Starlord
Subject: Re: Solar eyepiece projection safe for scope?
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I don't know about that EP, but I've been using a meade 25mm EP to projet
the image of the sun onto a white cardboard for viewing.
--
The Lone Sidewalk Astronomer of Rosamond
Telescope Buyers FAQ
http://home.inreach.com/starlord
Sidewalk Astronomy
www.sidewalkastronomy.info
The Church of Eternity
http://home.inreach.com/starlord/church/Eternity.html
"Florian" <saa@seeyouinthedark.com > wrote in message
news:j8x2h.10874$zy2.3995@tornado.socal.rr.com...
I feel i should know the answer to this but the more i think about it the
more unsure i am. Is it safe to point a Tele Vue 76 at the sun to project
the image on a white card? (Of course i know it's NEVER safe to look
directly into the eyepiece of an unfiltered scope.) Is there any chance of
damage to the internal workings of the scope, like the baffles, or to the
eyepiece or field stop? I'm planning to take my TV76 to work next Wednesday
to share the Mercury transit and was thinking to project the image on a
card. I also have a Baader solar filter so i may use both methods. The
advantage of the projection method is that many people can view at once.
.Florian
Stargazing.com
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Date: 02 Nov 2006 19:31:14
From: RMOLLISE
Subject: Re: Solar eyepiece projection safe for scope?
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Florian wrote:
> I feel i should know the answer to this but the more i think about it the more unsure i am. Is it safe to point a Tele Vue 76 at the sun to project the image on a white card? (Of course i know it's NEVER safe to look directly into the eyepiece of an unfiltered scope.) Is there any chance of damage to the internal workings of the scope, like the baffles, or to the eyepiece or field stop? I'm planning to take my TV76 to work next Wednesday to share the Mercury transit and was thinking to project the image on a card. I also have a Baader solar filter so i may use both methods. The advantage of the projection method is that many people can view at once.
>
> .Florian
> Stargazing.com
Hi Florian:
My advice? Don't do it. Stick with the filter. While it _probably_
wouldn't hurt the scope...temperatures inside the tube will get high
very quickly, and if there's anything in there that can be harmed by
heat, it will be. An eyepiece can also be damaged...field stops and
cemented elements being vulnerable. Also, I NEVER like to have an
unfiltered scope pointed at the sun if there are non-amateurs around
who might, when you're distracted, put an eye to the eyepiece. Stick
with the filter.
Peace,
Rod Mollise
Author of:
Choosing and Using a Schmidt Cassegrain Telescope
and
The Urban Astronomer's Guide
<http://skywatch.brainiac.com/astroland >
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Date: 02 Nov 2006 18:55:59
From: Mark D
Subject: Re: Solar eyepiece projection safe for scope?
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Hi Florian,
It should not cause any damage to your TV Refractor, but the best person
who can answer this, would be "Uncle" Al Nagler himself, and you can no
doubt pose this same question to those folks on the televue Website.
Since you have a Baader Filter though, this would be IMO a better way to
view the sun, and it also makes your scope a lot safer, (provided it's
attached securely) in that nobody can perhaps accidently take a peek
through the scope while it's pointed at the Sun.
Sounds perhaps unlikely, but all it takes is for you to turn your back
for two seconds to speak with someone else at the gathering, while a
unattended child decides to take a peek.
It's also wise to never have any other type of finderscope, etc attached
to the main Tube.
I'm sure you know to zero-in on the sun by looking at the scope's shadow
on the ground.
Mark
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Date: 03 Nov 2006 10:08:26
From: Brian Tung
Subject: Re: Solar eyepiece projection safe for scope?
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Florian wrote:
> I feel i should know the answer to this but the more i think about it
> the more unsure i am. Is it safe to point a Tele Vue 76 at the sun to
> project the image on a white card? (Of course i know it's NEVER safe to
> look directly into the eyepiece of an unfiltered scope.) Is there any
> chance of damage to the internal workings of the scope, like the
> baffles, or to the eyepiece or field stop? I'm planning to take my TV76
> to work next Wednesday to share the Mercury transit and was thinking to
> project the image on a card. I also have a Baader solar filter so i may
> use both methods. The advantage of the projection method is that many
> people can view at once.
It should be OK for the scope. Be sure not to use a diagonal. (Most
people don't, with projection, but it's best to make sure.) Use a cheap
eyepiece. The downside with projection is that there's less detail to
be seen in most cases than with a direct view through a filter; the
corresponding upside, as you say, is that if you have a lot of people,
you can have them all see it at the same time. Still, I've led an
entire class of 30 fifth-graders through a direct view with the H-alpha
filter, so I'd generally go with the direct view, myself.
--
Brian Tung <brian@isi.edu >
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.html
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Date: 04 Nov 2006 02:28:52
From: Florian
Subject: Re: Solar eyepiece projection safe for scope?
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Thanks for all the replies. I think i'll go with the Baader filter and =
just have ppl take turns viewing.
.Florian
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Date: 05 Nov 2006 10:27:00
From: Mij Adyaw
Subject: Re: Solar eyepiece projection safe for scope?
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Good idea, however, I wonder if it is possible to use the Baader filter and
attach a webcam and then display the real-time solar image on a laptop
screen... Of course you will need to shield the laptop from the sunlight so
that you can see the screen. It may be a better solution when many folks
want to view.
"Florian" <saa@seeyouinthedark.com > wrote in message
news:EVS2h.11068$zy2.1579@tornado.socal.rr.com...
Thanks for all the replies. I think i'll go with the Baader filter and just
have ppl take turns viewing.
.Florian
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Date: 05 Nov 2006 10:35:57
From: Mij Adyaw
Subject: Re: Solar eyepiece projection safe for scope?
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In thinking more about this, it most likely will not be possible to use a
webcam to image the sun because of the very small ccd in the webcam. The
resultant magnification will be excessive and it will only be possible to
view a small portion of the Sun. I wonder if there are any low-cost imaging
device on the market what will allow the entire disk of the sun to be
presented on a laptop screen?
"Mij Adyaw" <mij@TheBitBucket.com > wrote in message
news:U1q3h.11160$_k7.7869@newsfe07.phx...
> Good idea, however, I wonder if it is possible to use the Baader filter
> and attach a webcam and then display the real-time solar image on a laptop
> screen... Of course you will need to shield the laptop from the sunlight
> so that you can see the screen. It may be a better solution when many
> folks want to view.
>
> "Florian" <saa@seeyouinthedark.com> wrote in message
> news:EVS2h.11068$zy2.1579@tornado.socal.rr.com...
> Thanks for all the replies. I think i'll go with the Baader filter and
> just have ppl take turns viewing.
>
> .Florian
>
>
>
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Date: 03 Nov 2006 13:56:54
From: Alan French
Subject: Re: Solar eyepiece projection safe for scope?
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"Florian" <saa@seeyouinthedark.com > wrote in message
news:j8x2h.10874$zy2.3995@tornado.socal.rr.com...
I feel i should know the answer to this but the more i think about it the
more unsure i am. Is it safe to point a Tele Vue 76 at the sun to project
the image on a white card? (Of course i know it's NEVER safe to look
directly into the eyepiece of an unfiltered scope.) Is there any chance of
damage to the internal workings of the scope, like the baffles, or to the
eyepiece or field stop? I'm planning to take my TV76 to work next Wednesday
to share the Mercury transit and was thinking to project the image on a
card. I also have a Baader solar filter so i may use both methods. The
advantage of the projection method is that many people can view at once.
Florian,
I used my 60mm Unitron for years for solar projection, and never had any
problems. Just make sure to keep the sun centered so the converging light
cone does not strike the inside of the tube somewhere.
Clear skies, Alan
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Date: 03 Nov 2006 21:51:10
From: William Hamblen
Subject: Re: Solar eyepiece projection safe for scope?
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On Fri, 03 Nov 2006 13:56:54 GMT, "Alan French"
<adfrenchremoveallthis@nycap.rr.com > wrote:
>I used my 60mm Unitron for years for solar projection, and never had any
>problems. Just make sure to keep the sun centered so the converging light
>cone does not strike the inside of the tube somewhere.
Three inches probably is the biggest telescope he would want to do
eyepiece projection with. He would want to stop down larger ones. He
should use an eyepiece he wouldn't miss much if it popped. Ramsden
eyepices were good for the purpose because of no cemented lenses, but
noone has them any more. He could make his own from surplus simple
lenses. Viewing the projected Sun only a minute at a time would be a
good idea. He could throw a white towel over the telescope between
looks.
Bud
--
The night is just the shadow of the Earth.
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Date: 04 Nov 2006 03:45:32
From:
Subject: Re: Solar eyepiece projection safe for scope?
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Florian wrote:
> Thanks for all the replies. I think i'll go with the Baader filter and just have ppl take turns viewing.
>
> .Florian
You could also try a "pinhole reflector." Cover a mirror (first
surface if available) with a piece of cardboard that has only a 1/16th
- inch hole. Reflect the Sun's light through an open door or window
onto a smooth, light-colored wall or screen. A smaller hole and/or
larger distance to the wall will yield more detail but a dimmer image.
Experiment ahead of time.
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Date: 05 Nov 2006 11:23:31
From:
Subject: Re: Solar eyepiece projection safe for scope?
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A lens with a focal length of around 200-250 mm should provide a
reasonable image scale for a Webcam (4mm chip size?), if your goal is
to include the entire solar disc. During first and last contact a
longer FL would possibly provide more interesting images though.
(I prefer to look through a scope rather than at a screen.)
Mij Adyaw wrote:
> In thinking more about this, it most likely will not be possible to use a
> webcam to image the sun because of the very small ccd in the webcam. The
> resultant magnification will be excessive and it will only be possible to
> view a small portion of the Sun. I wonder if there are any low-cost imaging
> device on the market what will allow the entire disk of the sun to be
> presented on a laptop screen?
>
>
>
>
> "Mij Adyaw" <mij@TheBitBucket.com> wrote in message
> news:U1q3h.11160$_k7.7869@newsfe07.phx...
> > Good idea, however, I wonder if it is possible to use the Baader filter
> > and attach a webcam and then display the real-time solar image on a laptop
> > screen... Of course you will need to shield the laptop from the sunlight
> > so that you can see the screen. It may be a better solution when many
> > folks want to view.
> >
> > "Florian" <saa@seeyouinthedark.com> wrote in message
> > news:EVS2h.11068$zy2.1579@tornado.socal.rr.com...
> > Thanks for all the replies. I think i'll go with the Baader filter and
> > just have ppl take turns viewing.
> >
> > .Florian
> >
> >
> >
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