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Search: Posts Made By: Binastro
Forum: Spotting Scopes & tripod/heads Today, 12:42
Replies: 2
Views: 47
Posted By Binastro
Hi Chris, LER stands for Long Eye Relief. I...

Hi Chris,

LER stands for Long Eye Relief.

I don't know about the Viking eyepieces but maybe old Opticron eyepieces might fit?

Regards,
B.
Forum: Binoculars Today, 12:29
Replies: 3
Views: 186
Posted By Binastro
Hi Steve and welcome. I have the Savannah...

Hi Steve and welcome.

I have the Savannah 12x56ED which I like, but it works, so no spare parts.

I lived in Sunderland for several years and used to go clubbing in Newcastle, but that doesn't...
Forum: Leica Yesterday, 18:58
Replies: 37
Views: 712
Posted By Binastro
Dipped, As both exit pupils are round, the only...

Dipped,

As both exit pupils are round, the only variable is 42 and 32.
Or for area the ratio between 42 squared and 32 squared.

Pi just cancels out.

Regards,
B.
Forum: Leica Yesterday, 18:54
Replies: 37
Views: 712
Posted By Binastro
What has not been discussed, and which has far...

What has not been discussed, and which has far greater impact than exit pupils and eye pupils is dark adaptation.

This varies with great complexity.
It depends on age, and on whether one has been in...
Forum: Leica Yesterday, 18:39
Replies: 37
Views: 712
Posted By Binastro
Pies are round (: Unnecessary to introduce...

Pies are round (:

Unnecessary to introduce pi.

40+2 squared is 1604+160= 1764.
32 squared is 1024.

1764 divided by 1024 is about 1723 divided by 1000, so about 72%.
Forum: Leica Yesterday, 16:37
Replies: 37
Views: 712
Posted By Binastro
And then put the mask in front of the other...

And then put the mask in front of the other barrel or turn the binocular upside down (:

Or do both, as the transmission could differ between barrels in an older binocular, as well as differences...
Forum: Leica Yesterday, 16:03
Replies: 37
Views: 712
Posted By Binastro
Mark, The cones and rods of the eyes respond...

Mark,

The cones and rods of the eyes respond differently under different light levels.

B.
Forum: Leica Yesterday, 15:39
Replies: 37
Views: 712
Posted By Binastro
Although old I can easily see that my Swift HR/5...

Although old I can easily see that my Swift HR/5 8.5x44 is brighter than the 8x32 Leica BA at night.
My pupils are still over 5.25mm even with severe light pollution.

However, there is lot of glare...
Forum: Swarovski Monday 19th August 2019, 15:45
Replies: 8
Views: 580
Posted By Binastro
If this Swarovski monocular is pointed at a...

If this Swarovski monocular is pointed at a person, does it give the person's name, age etc.?

It could probably do this, if this was wanted.

B.
Forum: Leica Monday 19th August 2019, 13:36
Replies: 37
Views: 712
Posted By Binastro
I use Imperial and metric drill gauges. They cost...

I use Imperial and metric drill gauges.
They cost a few pounds each.
They have about 15 holes from say 1mm up. In three rows. I only need the smallest row and a couple from the middle row.
Made in...
Forum: Leica Monday 19th August 2019, 13:30
Replies: 37
Views: 712
Posted By Binastro
Lens hoods may or may not help. Some binoculars...

Lens hoods may or may not help.
Some binoculars have front threads and camera lens hoods can be screwed in.
At a pinch one could make some from black card.

You could get someone to look at your eyes...
Forum: Leica Monday 19th August 2019, 12:13
Replies: 37
Views: 712
Posted By Binastro
Hi Moose8, Have you actually measured your pupil...

Hi Moose8,

Have you actually measured your pupil size in twilight?
If you have a dark sky, see if you can see slightly fainter stars in the 8x42 compared with the 8x32.
Give yourself twenty minutes...
Forum: Spotting Scopes & tripod/heads Sunday 18th August 2019, 16:27
Replies: 15
Views: 486
Posted By Binastro
As to the original post. I doubt that a...

As to the original post.

I doubt that a birdwatcher wants to fill his car with a 30cm Dobsonian.
That is why I suggested a 6 inch or 8 inch.

One of my colleagues transports his 20 inch Dobsonian in...
Forum: Spotting Scopes & tripod/heads Sunday 18th August 2019, 14:29
Replies: 15
Views: 486
Posted By Binastro
Hi John, I thought so too. But this wasn't the...

Hi John,
I thought so too.
But this wasn't the case.

I think that Mercury was nearer 12 arcseconds diameter.

I first tried a filtered 7x binocular. It was easy.

Then the filtered 5x25 Foton....
Forum: Swarovski Sunday 18th August 2019, 14:13
Replies: 8
Views: 580
Posted By Binastro
Image stabilised? B.

Image stabilised?

B.
Forum: Spotting Scopes & tripod/heads Saturday 17th August 2019, 20:15
Replies: 15
Views: 486
Posted By Binastro
In the 1980s I bought a used 6 inch f/8 Newtonian...

In the 1980s I bought a used 6 inch f/8 Newtonian for 40.
The mirrors needed recoating as they were dull.

On looking through this telescope for the first time I was staggered by the quality of the...
Forum: Spotting Scopes & tripod/heads Saturday 17th August 2019, 17:16
Replies: 15
Views: 486
Posted By Binastro
My friend has both a superb 7 inch Astrophysics...

My friend has both a superb 7 inch Astrophysics refractor and an excellent Celestron C14.
The C14 is clearly better both visually and for world class planetary images.

Another planetary observer...
Forum: Spotting Scopes & tripod/heads Saturday 17th August 2019, 16:59
Replies: 15
Views: 486
Posted By Binastro
Hi, I agree with opisska. The great observer...

Hi,
I agree with opisska.

The great observer George Alcock used a 4 inch f/12 Ross triplet refractor to observe Mars.
Nobody believed his drawings or observations, as he was seeing as much as...
Forum: Nikon Saturday 17th August 2019, 16:41
Replies: 5
Views: 428
Posted By Binastro
Damian Peach takes his world class planetary...

Damian Peach takes his world class planetary astro photos from Barbados.

I don't know how he takes his 14 inch SCT there.
Maybe he has a second one that he leaves in Barbados.

Regards,
B.
Forum: Zeiss Saturday 17th August 2019, 16:14
Replies: 7
Views: 473
Posted By Binastro
Welcome. This looks like a genuine high quality...

Welcome.

This looks like a genuine high quality military Zeiss 7x50, but I am not a Zeiss expert.

Independent eyepiece focus.

No ports for inert gas.

The lenses seem to be single blue coated?, so...
Forum: Opticron Friday 16th August 2019, 16:33
Replies: 3
Views: 196
Posted By Binastro
One needs a thread pitch gauge or an Opticron...

One needs a thread pitch gauge or an Opticron eyepiece of known thread to try.

Opticron eyepieces usually have a part number on them.
I wonder if this is sufficient to identify the thread type?

Ask...
Forum: Zeiss Thursday 15th August 2019, 16:49
Replies: 19
Views: 1,062
Posted By Binastro
Thanks Canip. How about a test of the Swiss...

Thanks Canip.

How about a test of the Swiss Safran Vector family of binoculars?

Regards,
B.
Forum: Spotting Scopes & tripod/heads Thursday 15th August 2019, 15:26
Replies: 15
Views: 486
Posted By Binastro
Pluto (still a planet to me). It depends what...

Pluto (still a planet to me).

It depends what kind of astro observation.

Much more important is a dark clear sky.

For planets, to see any detail, one needs 100x.
For deep sky, clusters, nebulae...
Forum: Zeiss Thursday 15th August 2019, 14:54
Replies: 19
Views: 1,062
Posted By Binastro
Thanks Gijs, Canip and John. A 10% transmission...

Thanks Gijs, Canip and John.

A 10% transmission difference is noticed by eye. At least by testing the rangefinder binocular right way up and then upside down, as our two eyes differ. Hopefully the...
Forum: Zeiss Wednesday 14th August 2019, 14:52
Replies: 19
Views: 1,062
Posted By Binastro
Is the average transmission 3% less? Or is one ...

Is the average transmission 3% less?

Or is one barrel 6% less and the other 3% less?

Or is one barrel 3% less and the other 0% less?
(:

B.
Showing results 1 to 25 of 1000
 


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