Venus at noon

Chris L Peterson wrote:
On Fri, 9 Oct 2015 10:53:03 -0700 (PDT), wrote:

20x binoculars are uncommon, unlikely to be placed in a novice's
hands, and will result in an even more transitory exposure when hand
held.

10x binos then... are those common enough for you? We must assume that
any bino can end up in anyone's hands. Murphy's Law and all that.

It doesn't matter. It is still very difficult to permanently damage
your eyes with a pair of binoculars used in the daytime.

Do not try to overstate the danger again.

The danger cannot be overstated.

Yes, it can.


Looking at the sun when more than 5 minutes from from rising and setting
through 8x binoculars will damage the eyes and any prudent person would
never look at the sun through binoculars or a telescope.

Chris L Peterson wrote:
On Fri, 9 Oct 2015 11:26:11 -0700 (PDT), wrote:

The danger cannot be overstated.

Yes, it can.

No, it is quite possible that someone could be hurt if they were to be
influenced by your cavalier attitude towards the danger.

Why don't you just do the calculations? The total power delivered to
the eye with those 10X binoculars is under 500 mW. The power density
is around the same as you get with a 2 mW laser. The spot size is only
1.5 mm, which is small enough that the retinal vasculature is
efficient at carrying away heat. The visible and near-IR wavelengths
are not associated with phototoxicity.

In short, there isn't enough energy to damage the eye even within the
typical 0.25 second white-light blink reflex, and less so given that
the image will almost certainly be all over the retina with an
accidental sweep across the Sun.

It is always good advice to be careful when using telescopic
instruments near the Sun. But in fact, you CAN overstate the danger.
In this case, the possibility of somebody being hurt is very small.


The conclusion of the website below is: Don't do it
Thanks to the wonders of iOS9 I can't paste the appropriate section but you
will find it under "Telescopic Observations". Note that the damage is much
worse in those younger than 20.


http://www-rohan.sdsu.edu/~aty/vision/Galileo.html

On Fri, 9 Oct 2015 19:28:12 +0000 (UTC), Mike Collins
wrote:

The conclusion of the website below is: Don't do it.

Which I wholly agree with!

On Fri, 9 Oct 2015 19:17:25 +0000 (UTC), Mike Collins
wrote:

Looking at the sun when more than 5 minutes from from rising and setting
through 8x binoculars will damage the eyes and any prudent person would
never look at the sun through binoculars or a telescope.

You need to define "looking". I absolutely agree that if you aim your
binoculars at the Sun and deliberately hold it steady for a few
seconds, you will permanently damage your retina.

My point is that accidentally scanning across the Sun with those same
binoculars almost certainly will not.

wrote:
On Friday, October 9, 2015 at 11:52:40 AM UTC-4, Mike Collins wrote:
wsnell01 wrote:
On Thursday, October 8, 2015 at 3:52:34 PM UTC-4, Mike Collins wrote:
For decades I've wanted to see Venus at noon. Today the sky was clear at
13:30 BST (12:30 UT) and the crescent moon was visible not too far from
Venus. Venus was easily visible through 10x8s and thanks to the nearby moon
as a reference naked eye focus it was just visible to the naked eye. Only
30 minutes after noon which is my new record.

A few words of caution are in order here. The Sun was only a few
binocular fields away from Venus at the time. Take stringent precautions
and do not allow children or stupid adults (such as peterson) to attempt
this observation. At the very least be -completely- and well within the
shadow of a large building in order to avoid accidentally sweeping across
the Sun with your binocular(s). =


That's how I observe these things. I have a yard (read patio for USians)

We Americans often have yards and patios, the yard being the area covered
(mostly) by grass and the patio being a paved recreational area in the yard.
Most UKians probably don't have room enough for both, due to overpopulation.

to
the north of the house with a good west view. Children would have to be
fairly tall to look through my binoculars on a tripod at my eye height.
Your concern reminds me of a sign in a lab I used to work in "Do not look
into laser with remaining eye."


I was tailoring my comments to a broader audience who will probably have
circumstances differing from yours.


Now, with that being said, perhaps you should have used a GoTo scope to
"find" Venus and a video cam to observe it. That way you would be seeing
Venus "as it really appears" and not the "inferior view" one would get
when looking at it the "traditionalists'" way, ie, through an eyepiece. ;-)

Several problems he
I don't have a goto scope.

Why not?

I tend to make naked eye observations with the naked eye.

According to LsD you shouldn't be doing that!

The binoculars are just an aid to finding Venus.

According to LsD you shouldn't be using those either!

Today they were an aid to
finding the moon which, at 10% illumination was very difficult to see with
the naked eye. Venus was easy in binoculars but not visible to the naked
eye, at least not my naked eye.

LdB probably walks around looking at the screen of a mobile phone rather
than sullying his perceptions with an unassisted view.

Agreed.



To us a yard is paved and what you describe as a yard is a garden. Unlike
most of Europe the English like gardens although high house prices mean
that new houses only have a small area outside. However my house is 200
years old and has a garden and a yard.

Why don't I have a toto scope?
A Newtonian with GEM and manual slow motions is good enough to find what I
want to observe.

On Friday, October 9, 2015 at 3:19:30 PM UTC-4, Mike Collins wrote:

Looking at the sun when more than 5 minutes from from rising and setting
through 8x binoculars will damage the eyes and any prudent person would
never look at the sun through binoculars or a telescope.

They certainly should not do so on purpose and by extension should take huge precautions in order to avoid doing so accidentally as well. In addition to damage to the retina there is also damage to the iris to consider. Not to mention that the victim of such an event will not be able to see and may trip or be a hazard to others, cause great emotional distress or precipitate some bad judgement.

On Friday, October 9, 2015 at 3:03:12 PM UTC-4, Sam Wormley wrote:
On 10/9/15 1:26 PM, wsnell01 wrote:
ANOTHER irresponsible comment that had to be deleted.

How childish.

The statement that I deleted could very easily be misinterpreted and lead to grievous injury to an unwary victim. There is nothing childish about my deleting it nor about my response to it.

Get a clue, wormley.

On Friday, October 9, 2015 at 5:04:36 PM UTC-4, Mike Collins wrote:


To us a yard is paved and what you describe as a yard is a garden. Unlike
most of Europe the English like gardens although high house prices mean
that new houses only have a small area outside. However my house is 200
years old and has a garden and a yard.

A garden here usually means either a vegetable garden or a place of almost any size where ornamental plants are featured, with or without additional landscaping.

A grassy area is loosely referred to as a lawn, although strictly speaking a lawn is just the grass, not the area.

Occasionally someone will pave the area in front of his house in order to have a place to park, but it is still called the "front yard."

Townhouses don't usually have usable front yards, but often have areas in the back that -could- be called "backyards."

Why don't I have a toto scope?

My question was purely tongue-in-cheek.

On Friday, October 9, 2015 at 3:30:18 PM UTC-4, Mike Collins wrote:

The conclusion of the website below is: Don't do it
Thanks to the wonders of iOS9 I can't paste the appropriate section but you
will find it under "Telescopic Observations". Note that the damage is much
worse in those younger than 20.


http://www-rohan.sdsu.edu/~aty/vision/Galileo.html

The link at the bottom of 'Telescopic Observations' is chilling:

http://www-rohan.sdsu.edu/~aty/visio...rs.html#Bunker

This is nothing to brush off lightly.

Mike Collins:
The conclusion of the website below is: Don't do it
Thanks to the wonders of iOS9 I can't paste the appropriate section but you
will find it under "Telescopic Observations". Note that the damage is much
worse in those younger than 20.

http://www-rohan.sdsu.edu/~aty/vision/Galileo.html

Regardless of what he might have gotten right, the smug-ass pedant who
authored that web page lied in suggesting fraud on the part of Company
7 (C7). That is outrageous. I have known Martin Cohen of C7 for a long
time, and I know how he does business. *If* he erred in attributing
Galileo's blindness to observing the Sun it was due to believing a
popular--and quite reasonable-sounding--myth, not for the purpose of
defrauding the public by selling safe solar filters. Go into C7 and
insist on buying a telescope for solar observing without a safe solar
filter and Martin will tell you to buy your telescope someplace else.

Martin cannot compete with the big on-line sellers. A lot of his
business is with NASA, universities and other research organizations
around the world, such as JHUAPL, that demand top-quality equipment.
Martin doesn't sell on-line because he feels he has to know what a
customer expects from their equipment before making a recommendation.
He does that in person, by phone, or by e-mail. That settled, the
telescope is not drop-shipped from the supplier, but it comes to C7
where it is checked out on the best optical and mechanical test
equipment available. If it fails--as popular brands often do, and
research-grade instruments sometimes do--it goes back to the
manufacturer. When a telescope has met or exceeded the manufacturer's
published specs, and is free of mechanical defects, and C7 can certify
it as defect-free by those standards, only then is it re-packed and
shipped to the customer.

It's Martin's experience and excellence in optical testing that led
NASA to invite him to assist in testing the Hubble WFPC2 for the
original optics correction mission.

A conscientious and responsible dealer like C-7 cannot fail to warn a
customer of the need to protect their eyes when observing the Sun. To
suggest that C7 does this only to profit from the sale of solar filters
is scandalous.

--
I agree with almost everything that you have said and almost everything that
you will say in your entire life.

usenet *at* davidillig dawt cawm