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Search: Posts Made By: Binastro
Forum: Binoculars Today, 14:07
Replies: 8
Views: 148
Posted By Binastro
Bicycle tube rubber directly over the...

Bicycle tube rubber directly over the threads.

3D printing?

Would a 35mm film canister fit over the thread and add bicycle tube rubber, after cutting the film canister to the correct...
Forum: Nikon Today, 07:54
Replies: 1
Views: 126
Posted By Binastro
Nikon Travelite EX 10x25. Yesterday morning the...

Nikon Travelite EX 10x25.
Yesterday morning the Moon was almost exactly full. No shadows.
This morning 2.30a.m., one day after full, there was a great deal of detail in both barrels. Although the...
Forum: Nikon Yesterday, 18:35
Replies: 1
Views: 126
Posted By Binastro
Nikon Travelite EX 10x25

Also known as ProStaff WP.
5 degrees.
Waterproof.
360g.

Bright sunshine 8.30 a.m.

New Nikon 10x25 compared to as new 10x25 Trinovid and c.1980? very heavily used Docter 10x25.

Also Hyades large...
Forum: Binoculars Thursday 12th September 2019, 13:58
Replies: 15
Views: 462
Posted By Binastro
The Light gathering power relating telescope...

The Light gathering power relating telescope aperture to a 7mm pupil is wrong.
However it is important to maintain this fiction, which has been used for decades, to provide consistency.

The...
Forum: Binoculars Thursday 12th September 2019, 13:31
Replies: 15
Views: 462
Posted By Binastro
It is correct that the surface brightness in a...

It is correct that the surface brightness in a telescope image is always less than with unaided eyes.
Unless one has an image intensifier.

I think that there is an insect that actually has an image...
Forum: Canon Thursday 12th September 2019, 09:37
Replies: 33
Views: 1,220
Posted By Binastro
I wonder how long Dennis will keep this...

I wonder how long Dennis will keep this binocular(:

Regards,
B.
Forum: Binoculars Thursday 12th September 2019, 09:23
Replies: 15
Views: 462
Posted By Binastro
With regards to limiting magnitudes. Mount Wilson...

With regards to limiting magnitudes.
Mount Wilson observers with a 60 inch scope I think or maybe a 100 inch reported a limit of magnitude 16 or so.

However, a very respected variable star observer...
Forum: Binoculars Thursday 12th September 2019, 09:03
Replies: 15
Views: 462
Posted By Binastro
Hypothesis, individual opinion, theory. None of...

Hypothesis, individual opinion, theory.
None of this actually matters.

What one has to do is to get some skill at actually observing stars.

Then get an accurate star chart of visual magnitudes, say...
Forum: Zeiss Thursday 12th September 2019, 08:43
Replies: 32
Views: 10,212
Posted By Binastro
Well done. It doesn't surprise me the buyer is...

Well done.

It doesn't surprise me the buyer is in China.
Sometimes a hand is just put up at an auction and left there until the object is bought.
The fascinating thing is when two people keep their...
Forum: Binoculars Wednesday 11th September 2019, 22:39
Replies: 15
Views: 462
Posted By Binastro
Regarding looking at reflections of the Sun etc....

Regarding looking at reflections of the Sun etc. or distant welding torches with telescopes.
Safety first. If in doubt, don't do it.

This whole topic takes a lifetime of experience.
Even well known...
Forum: Binoculars Wednesday 11th September 2019, 22:13
Replies: 15
Views: 462
Posted By Binastro
A 20x50 binocular will commonly show stars almost...

A 20x50 binocular will commonly show stars almost twice as faint as a 10x50. Even hand held.
This is thought to be because the background sky brightness is decreased and contrast increased. Stars are...
Forum: Zeiss Wednesday 11th September 2019, 19:47
Replies: 9
Views: 364
Posted By Binastro
See Night Owl 10x56 Wow. Birdforum August 2007...

See Night Owl 10x56 Wow. Birdforum August 2007 for discussion of these and 7x45.
Optically very good but heavy.

B.
Forum: Zeiss Wednesday 11th September 2019, 19:41
Replies: 9
Views: 364
Posted By Binastro
This binocular has been discussed here...

This binocular has been discussed here before.

Isn't it very heavy and cumbersome?

It may be almost new because of this?
I haven't handled one so I don't know.

But if cheap enough!

Regards,
Forum: Leica Wednesday 11th September 2019, 17:42
Replies: 35
Views: 907
Posted By Binastro
There are instructions for clinicians to adjust...

There are instructions for clinicians to adjust the 7x30 Beechers Mirage to the patient.

The correct distance from the eye lens to the eye is 10mm. But I don't know if one can fit corrective lenses...
Forum: Leica Wednesday 11th September 2019, 15:56
Replies: 35
Views: 907
Posted By Binastro
The smaller Beechers Mirage are Galilean, but the...

The smaller Beechers Mirage are Galilean, but the larger ones I think use high reflection mirrors to provide an upright image similar to the Russian 30x50.
I don't think that a Galilean 7x30 would...
Forum: Leica Wednesday 11th September 2019, 15:09
Replies: 35
Views: 907
Posted By Binastro
For some people the Beechers Mirage 7x30 might be...

For some people the Beechers Mirage 7x30 might be something to consider.
I don't know how it works with eyeglasses. Maybe prescription lenses could be attached to the eyepieces.

It weighs 3...
Forum: Bushnell - Bausch & Lomb Tuesday 10th September 2019, 17:14
Replies: 2
Views: 136
Posted By Binastro
Possibly Opticron? Regards, B.

Possibly Opticron?

Regards,
B.
Forum: Spotting Scopes & tripod/heads Monday 9th September 2019, 17:22
Replies: 10
Views: 293
Posted By Binastro
It takes a lot of practice to keep both eyes...

It takes a lot of practice to keep both eyes open, and maybe best done as a youngster.
One has to be relaxed doing this with no strain.

We get set in our ways as we get older.

B.
Forum: Spotting Scopes & tripod/heads Monday 9th September 2019, 17:15
Replies: 25
Views: 741
Posted By Binastro
The paper on U.S. Navy pilots made it clear that...

The paper on U.S. Navy pilots made it clear that the tolerances were not good enough.

The optical trade is quite capable of higher standards, but costs are as usual the determining factor.

+/-7...
Forum: Spotting Scopes & tripod/heads Monday 9th September 2019, 17:03
Replies: 10
Views: 293
Posted By Binastro
I have done this when needed for well over fifty...

I have done this when needed for well over fifty years.

As an astronomer I trained myself from age 15 to keep both eyes open and ignore the view in the other eye.

Periodically, I would also refocus...
Forum: Binoculars Monday 9th September 2019, 16:11
Replies: 13
Views: 1,006
Posted By Binastro
Hi 42za. Well done and praise be. The price is...

Hi 42za.

Well done and praise be.

The price is similar to U.K. prices.

If he or she does good work let him or her clean any other binoculars that need care and attention, at least while able to do...
Forum: Spotting Scopes & tripod/heads Monday 9th September 2019, 16:00
Replies: 25
Views: 741
Posted By Binastro
Re. opticians. My eye tests take 1.5...

Re. opticians.

My eye tests take 1.5 hours.
Maybe not many opticians are willing to take this time.
I understand that most opticians don't prescribe to 1/8 dioptre or 2.5 degrees. Yet their...
Forum: Spotting Scopes & tripod/heads Monday 9th September 2019, 15:20
Replies: 25
Views: 741
Posted By Binastro
David, I agree that that the first look through a...

David,
I agree that that the first look through a really top telescope can be shockingly good even with lower magnifications.
But it takes a lot of time to test it properly.

Telescopes that have...
Forum: Spotting Scopes & tripod/heads Sunday 8th September 2019, 22:22
Replies: 25
Views: 741
Posted By Binastro
I disagree. Looking at a known object such as a...

I disagree.
Looking at a known object such as a test chart, one would possibly see differences at 50x.

However, discovering hidden detail takes higher powers, in my experience at least 60% more to...
Forum: Spotting Scopes & tripod/heads Sunday 8th September 2019, 20:33
Replies: 25
Views: 741
Posted By Binastro
Hi John, I suppose the basic difference is that...

Hi John,
I suppose the basic difference is that birdwatchers generally don't choose the place and time, and observe even if it is raining.

If the conditions are poor I just don't bother to observe...
Showing results 1 to 25 of 1000
 


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