Highest feasible terrestrial magnification? (1 Viewer)

I'm moving to a new apartment in a few months. It has a glass enclosed balcony with possibility to remove panes, but still enjoy freedom from vibrations caused by wind. I will see a 40 degree slice of the sea towards south, but most of the view is panoramic towards east and the hinterland.
There are good chances to see migratory seabirds like Eiders, and most likely Northern Gannets, Skuas and such when it's stormy.
Height above the sea would be in the 45-50 m range.

Provided that sufficient aperture could allow for an 1,5 mm exit pupil, and almost no aperture limits applied, which magnification would hit the ceiling with regard to atmospheric conditions?
I could never afford a 14 inch reflector, but is there a chance to reach >200x magnification or will non-optical conditions make it useless?
This is a thought experiment and I'm not ruminating a new purchase round.
Yet. o


Thanks in advance!

//L

I've no practical experience in your location. On a bad day, where I've been, 30x is the max. Usually, I can go to 50x if I can get some elevation to get above unstable near-ground/water air. On a good day, 75x looks perfectly uncompromised, so I can tell that 150x would still be quite good.

A further comment is that depending on the temp indoors versus out, you might be better off looking through a high quality piece of glass (window glass) than through an open window and the consequent mixing unstable air.

--AP

Did some googling, and a rule of thumb was mentioned somewhere, saying that a magnification corresponding to the aperture in millimeters is expected. There were however people who claimed that twice that magnification could be obtained with a good sample, but that it won't be an enjoyable sight. I can understand that, with a 0.5 mm exit pupil. Good daylight would be beneficial, I guess.
Nobody could really answer how often conditions are perfect for terrestrial viewing, but what are your experiences?
Can terrestrial 200x - 300x ever come with a useful image, if it's a big and good scope?

//L

Alexis Powell said:

I've no practical experience in your location. On a bad day, where I've been, 30x is the max. Usually, I can go to 50x if I can get some elevation to get above unstable near-ground/water air. On a good day, 75x looks perfectly uncompromised, so I can tell that 150x would still be quite good.

A further comment is that depending on the temp indoors versus out, you might be better off looking through a high quality piece of glass (window glass) than through an open window and the consequent mixing unstable air.

--AP

Click to expand...

Thanks Alexis, that is the kind of answer I was looking for. :t:
The temperature can probably be similar to outside, or be adjusted to. The glass quality is yet to be discovered. Hopefully, it doesn't have to be swapped to better glass.

//L

Hi,

quick test - grey late morning in Frankfurt, outside temp 6 deg centigrade, distance 150m over water, subject a cormorant in the trees across the river.

Instrument used: 120mm f7.5 ED refractor (SW120ED) in unheated sleeping room through double pane window at 20 deg from orthogonal.

180x - 5mm Nagler type 6 - sharp but very dark as expected at 0.7mm exit pupil in so-so light - still could count feathers in head plumage...
100x - 9mm ES 100 - a more enjoyable view due to more usable brightness, but still more detail could be seen at 180x

Joachim

Lars,
The answer is yes if carefully planned.
The problem with viewing south is the Sun. However, if the angle between you and the Sun is large it would be good.

My Skywatcher 90mm Maksutov can easily be used at 190x through my kitchen double glazing at 124 metres. Crow on Chimney pot. Bird looks enormous with huge detailed eyes.
However, 125x is most comfortable with this aperture.
(This is at 45 degrees to the window glass horizontally).
Bright sunshine, Sun at 20 degree elevation almost behind me.
Central heating off.

Best conditions are autumn, spring.
Early morning or late afternoon.

Swedish air is probably cleaner than here.

My 120mm f/8.3 refractors at 250x could resolve black markings 1 arscecond size on a backlit lit clock window about 25 metres off the ground over a distance of 7.5km of suburbia and parks, but only at 3a.m.
Window open for 1.5 hours unheated bathroom.
Me dressed fully to stop body heat affecting the Seeing.
This was done fairly often.
My observation height about 10 metres.
In the daytime 30x might be poor with poor conditions.

Ideally the ground, air and water should all be at 16C/60F.

My 12.5 inch windowed thin edge mirror Dall Kirkham could be used at 300x during the day in ideal conditions.

Horace Dall's 8 inch Maksutov was unbelievable at 400x or more through his 4th floor attic window plate glass, selected and worked, perhaps 45 degree elevation, but of course at night. This was on Mars and was as good as my 12.5 inch Dall Kirkham.
High up in Luton on top of a hill in his specially made house.

My friend recently bought a wall clock from ASDA for £6.
He kept the front glass and housing and chucked the clock.
He put it on the front his 8 inch Newtonian.
He is an experienced astronomer and was an engineer.
At 150x he reports good star images in and out of focus both ways.
He just used it on the Moon at 200x and says the image is crisp with no degradation due to the glass.
I think that he has a lucky clock, as I doubt all would be as good.
He thought of using a glass solar filter and removing the special coatings, but although much cheaper than a worked optical window, which might be £1,000, the clock glass is much neater.

My 150mm Maksutov was usually used at 95x in the day, but 150x was easily usable.
An American 8 inch SCT, not Celestron was really good at 150x looking over the sea at 2km.
The name will come to me, but a rather poor reputation scope.

Rev Dawes frequently used 400x on his 6.5 inch refractor on planets and Jupiter's moons.

So with learning 200x plus is quite possible, even useful with lots of ifs.

Regards,
B.

Hi Lars,
In Sweden there may be double or triple glazing.
If the balcony window glass can be arranged to leave a single glass element it would be best for through the glass viewing.
Even with double glazing the optical quality of the glass varies depending which bit of glass one is looking through, so find the best optical bits of glass.

The larger the scope the more the window affects the scope.
So a good 5 inch refractor might be suitable.
Dobsonian scopes are low priced but not practical.
A good tested secondhand Celestron 8 inch SCT would be a good instrument for your purpose.
Or the simplest new tube and optics on a heavy mount.

The 1970s C8 I used was not good due to temperature effects.
On only one viewing night did it perform as a good 8 inch scope should and the planetary images were amazing. Usually they were poor.
I think the quality of these scopes is usually better nowadays.

My 4 inch f/12 Pentax could be used at 200x and more during the day. It was the importer's demonstrator and probably had essentially perfect optics. The Pentax ortho eyepieces. apparently were about as good as they get.

However, looking at moving birds in the day must be out at 200x plus, so presumably they will be stationary.
The FOV is very small at 200x.
I would use Nagler 82 degree eyepieces for this application.

Horace Dall's wife said I could have her late husband's plate glass window, which was covering the tomatoes.
I took the large 3 element window which just fitted in the Saab 900, but alas it was not the chosen glass.
I think somebody got his windows before I tried.

With open windows the temperature inside and outside must be the same, with a light breeze, or calm but no fog.

In my experience, perfect conditions occur about once a year.
It depends on the location.
The Hubble telescope probably has perfect conditions often, but it is outside our atmosphere.

Sufficiently good conditions for 200x with the sun above the horizon, maybe once a week for short chosen periods.
The apartment must be unheated, or at least the balcony.

If the apartment is heated, then one must leave, say, twenty minutes with the door to the balcony closed, so that the balcony can reach thermal equilibrium with the air outside.
The telescope must be left for at least an hour, maybe 1.5 hours till it reaches outside temperature.
If a SCT and it mists up then very light use of a hair dryer will clear mist.
Too much heat can crack glass, or indeed too much cold. I.e. thermal shock.
A long lens hood, wrapped around the front is most useful, perhaps a thin rubber or similar mat.

By the way, at night, I have used 600x and 750x on the 12.5 inch Dall Kirkham to good effect.
On Jupiter's moons.
1100x was empty magnification.
With large observatory telescopes, 1000x to 1,500x is the highest practical power at night. Up to 40 inch refractors and 100 inch reflectors.

B.

Thanks gentlemen,

valuable information as always. Maybe I should stress that the viewing distance rarely will be less than 1200 meters. Towards east (hinterland) it may be up to 15-20 km. Towards south/southwest probably from 1.5 kilometers and to the horizon, which from that height above sea level means about 28 km.

Yesterday I discovered that there is a slight possibility that I could see the lighthouse on the Danish island Anholt, 54 km away.
This would require extreme magnification, since only a small part of the lighthouse would protrude above the horizon, and my guesstimate is that its width is about 6-8 meters.
Considering that the lighthouse, if ever visible, by far would be the farthest terrestrial object visible, I think that any magnification exceeding 200x would be waste. It would correspond to seeing it at 270 m.
And migrating Eiders 4 km out would with 200x correspond to seeing them at 20 meters with the unaided eye.
Golden Eagles and Ospreys towards 16 km east would be like 80 meters.

The balcony is glass enclosed and not heated, so the door is densely insulated. It has a ceiling too, and generally good possibilities to avoid the sun. The spotting scope or telescope can be there permanently.
I have a Celestron C90 with a WO dielectric star diagonal, and the generic 45 degree diagonal.
The Fieldscope ED82A is better, I think, but I haven't compared them side by side. With the Wide DS 50x and a handheld 2.5x doubler, 125x might be the upper limit. Pushing it to 187x with the 75x Wide DS would probably not be a good idea.

The 100 mm semi-APO binoculars look interesting, but how far could they be pushed with regard to magnification, and could immaculate collimation be expected? If not, they're useless.

Another beast to consider could be a good 100 mm spotting scope. The straight old Pentax would probably deliver the highest quality images, but the angled Celestron Regal might be ergonomically and financially better. Not sure though how they fare against my Nikon, which I think is a cherry. An ATX 95 would never be considered for several reasons.

So 175x-200x should definitely cover everything. With an 8 inch scope, it means a 1 mm exit pupil, not really perfect but probably usable. The Fieldscope at 187x would produce a 0.4 mm exit pupil. Probably just an experiment for the sake of fun.

//L

Hi Lars,
The scope my friend had was a Criterion Dynamax 8 inch SCT and gave splendid daytime views from his south facing balcony, despite poor general reviews.
1970s.

The distance to the island was about 2.5 km and he used to use his sea going kayak to go there. He was a professional navy diver in WW2. He turned down a date with Marilyn Monroe before she was well known. As a civilian he was a movie cameraman, using Mitchell? cameras.

Malta is visible from Sicily and vice versa.
A church steeple and buildings were visible on Sicily from Malta using a 62mm refractor at a distance of 100 kms.

Very recently my friend saw masts on the Isle of Wight from Brighton at a distance of about 70 kms using a small spotting scope. Cloudy but superbly transparent air.

In good conditions the lighthouse at 54 km should be rather easy, depending on its height.
The light should be an easy unaided eye target.
There may be mirages with upside down ships on top of real ships between the lighthouse and your location.

I think that Joachim's SW120ED 120mm f/7.5 refractor would be an excellent choice and be better than 100mm spotting scopes.

It depends how much room there is on the balcony.

A 150mm or 180mm Maksutov would be good, but they are very slow to cool if taken from hot to cold. But if left on an unheated balcony they would be fine. A good one excels for distance observations and they are used by the military.

It is the temperature differences and weather that are far more important than the optics for viewing at 1200 metres and more.
The other consideration is heat from apartments below and the general thermal footprint of the building.
In addition, buildings and concrete or asphalt between your observing location and the sea could upset the view. Grass and vegetation is better.

Horace Dall had photos of a church gutter 17 miles or 27km from his 108mm f/30 camera obscura corrected for 4 colours. They were excellent.

He also photographed Mercury with his 16.5 inch Dall Kirkham using an equivalent focal length of 900,000mm.
(I remembered 1100 metres earlier probably incorrectly).
He used the atmospheric dispersion corrector that he invented that uses prisms to cancel the effects of atmospheric dispersion.
Modern copies are available commercially.

Regards,
B.

P.S.
My 127mm Skywatcher Maksutov is rather average or poor as is an old custom 90mm.
The 90mm SW Maksutov is very good as is the 89mm Questar.
The two custom 150mm Maksutovs are good. An f/10 and an f/15.

Russian Maksutovs have a reputation for fine optics but heavy construction. Not a problem in a fixed location.
The 5.5inch De Oude Delft Maksutov I tested was superb.
Maksutovs can easily take 200x if say 5 inch aperture and above with good optics and f/15 about.

Even the Vixen binoculars with maybe 8 eyepiece sets max out at 100x.
At 75x to 100x collimation is a real problem, although there was I think an Alvan Clark long focus 6 inch binocular telescope that was superb at all powers.
There was also a 300mm APO binocular made in Germany until recently.

For this application, I think that a binocular is a non starter, although a binocular viewer on a large scope might work.

Hi Lars,
Is the idea of a 100mm spotting scope based on the possibility of a dual purpose instrument?
To be used on the balcony and also in the field.
In my opinion this is a compromise and does not use the potential of the balcony.

I have a lot of experience with telescope observing from apartment balconies, although they were open to the outside air.
Your enclosed balcony might be better, if one could observe through good quality glass.

As to the lighthouse in Denmark. From photos it seems that the top may be stone coloured. This may prevent it being seen as it is basically camouflaged, although it might be seen in profile.

The sun question to the south is not so much the sun itself, but the direction of the light. Looking north would have the sun behind giving better illumination, contrast and visibility of distance objects.

In my opinion a 100mm spotting scope is just too small for the intended balcony use.
I think that a minimum of a good 5 inch or 6 inch refractor is needed.
The SW 120ED would be O.K. or the SW 150ED, although the focal ratio is quite short here.

The Esprit triplet objective refractors might on the face of it seem better. They may be better optically, but may also have more thermal problems. I don't know.
The only triplet refractor I have tested was a Ross 100mm f/15, which was superb, but long focus and rather small in this context.
Although my 100mm f/12 Pentax was extremely good, the same quality 135mm f/16 observatory refractor was better, just because it was bigger.

A 150mm or 180mm very good Maksutov is another good option.

Or a good Celestron 8, Celestron 9.25 or Celestron 11.
I hear good things of the Celestron 9.25 inch SCT. I think this would be my choice.

The telescope in my opinion should be a planetary quality telescope and not a compromised spotting scope or deep sky scope.

Obviously, value for money is a major consideration.

One of my friends uses either a Celestron 14 or a 7 inch Astrophysics refractor for his world class images.
The Celestron 14 gives better results.
The mount is very good.
New these are very expensive, and even good secondhand probably out of the running here.

Another astronomer takes his Celestron 14 to the West Indies where he has found superb Seeing conditions and nearer the equator. Shipping the scope and mount must be an interesting exercise.

Hi,

for a stationary instrument in your situation I would strongly recommend to look at astro scopes, be they lens or mirror. They will give you a lot more options for higher magnification with usable exit pupils and will be a lot cheaper than a comparable spotting scope - if there is any at that aperture, that is. And their disadvantages of higher weight and lack of waterproofing are not an issue to you.

A 5" Synta ED doublet like my SW 120 ED is going to set you back 1500€ new or 2/3 of that used, they also have a 6" option for 2k€ new which is quite unbeatable. The 5" has shown consistently high quality over many years, the 6" is fairly new but reviews are generally good too.

If you enter the domain of mirror or catadioptric telescopes, which is quite mandatory beyond 6" as larger refractors tend to get really expensive beyond that, another disadvantage, the need for proper adjustment gets an issue, but once again, unless you move it often, it should hold the proper setting pretty well.

Big binos are of course nice, but the potential for decollimation is certainly there (and unlike adjusting a mirror telescope, collimating binos takes specialised equipment and knowledge usually not available to amateurs - btw, how's your 2nd book, Bill?). The two pairs of APM 120 triplet binos I know from the astro club are great though.
But reaching 200x with them is a bit of a hassle - they have a focal length of 660mm which means you want a 3mm EP for that, which limits your options a bit.
Plus for the money you can easily get a 6" or larger ED refractor... or a really big Schmidt-Cassegrain like a C11 or a used C14.

Joachim

In practice if both telescopes are high quality, the Skywatcher 150ED refractor and Celestron 9.25 SCT would have similar resolution.
The brightness of the image in the Celestron 9.25 would be about double that of the 150ED at the same magnifications.
The exit pupil diameter of the Celestron 9.25 is about 50% bigger than the 150ED.
The tube weights seem to be similar.
The prices are similar.

The Skywatcher 180mm Maksutov is something of a bargain at £900. But I don't know how good they are. The focal length is 2,700mm and would take high power well.
The 150ED could take much lower powers than the other two.
I am not sure if the Celestron 9.25 takes 2 inch barrel eyepieces but the refractor and Maksutov seem to.

However, the 150ED may be too long for the balcony, so this has to be considered.
Russian high quality 7 inch Maksutovs seem to be more expensive.
The refractor is more or less maintenance free, whereas the other two need more care and attention.

A simple heavy tripod would suffice for terrestrial viewing, but would be more expensive as a driven astro mount.

Don't forget what happens at magnifications below 100x with these very large SCTs. Besides having very narrow maximum real fields the central obstructions of large SCTs cause a visible loss of contrast when their diameter exceeds a certain percentage of the full aperture. I believe Horace Dall specified 20% and some other sources say as little as 10%. The C-11 has a very large 95mm secondary, about 34% of the aperture, already large enough to degrade image quality compared to an unobstructed scope. Things get much worse in bright daylight where the eye's 2.5mm pupil will reduce the effective aperture of the C-11 at a "low" magnification like 50x to about 125mm with a whopping 76% effective central obstruction. Should you ever want to use a C-11 as low as 50X in bright daylight the image quality will be very poor and the AFOV can be no larger than about 25º since the maximum real field of a C-11 is only 0.5º.

Henry

Hi Henry,
That is correct.
My 12.5 inch Dall Kirkham had a 25% secondary obstruction.
Planetary Newtonians, particularly 10 inch f/9, or maybe 9 inch f/10, have as little as just over 10% central obstructions, but use very small fields.

The reason that the SCTs and mirror lenses have such large obstructions is for use for photography.

I have a Samyang 800mm f/8 lens and the contrast is very poor, much worse than it should be, even with its large central obstuction.
Similar lenses from Minolta, Nikon and Canon are probably much better.

Small mirror lenses, like the 250mm f/5.6 Minolta, which have become valuable for collector reasons, have very large secondaries, but are the size of a large standard lens.
Unfortunately I gave one away, but still have my original one.

Maksutovs traditionally have 25% central spots and work at about f/15. My f/10 needed a separate secondary rather than using the back of the corrector.

The other problem with Maksutovs and SCTs is that the correctors can either crack or break if dropped. So could a refractor objective, but the mirror types are less forgiving.
The Maksutov shells are thick and have problems cooling with large temperature differences. But at ambient temperatures they can provide great high magnification views.
The SCT corrector is thin, but I have seen them broken.

Ideally, for the task in hand of long distance viewing one would use the Harvard 9.5 inch f/12 refractor or the Northumberland 12 inch f/20 refractor with its new objective with special glass.
But they won't fit on a balcony.
Neither would the Zeiss 30 cm binoculars from 1930s/1940s.
There was someone in New York who had a long focus 11 inch refractor mounted on a truck, which he parked, and showed people the top of the Empire State building, maybe for a small charge.

In the current Sky and Telescope magazine there is an interesting Binocular Newtonian with only 4 mirrors, not six, with staggered primaries.

The simplest solution for the balcony viewing is probably the Skywatcher 150ED, but the exit pupil at 200x is 0.75mm. I am still able to use this well, but some may not like it.
It may also be too long depending on the size of the balcony.

I used to observe happily with the 150mm Maksutovs from balconies and also from indoors and non astronomers who looked through them were startled at the view at 100 times or more. They just didn't believe that such close ups were possible.

The Celestron 11 has a focal length of 2,800, so 50x would need a 56mm eyepiece,
I have 50mm and maybe 60mm eyepieces in 2 inch barrels, Kelner and maybe Hastings? There may also be a commercial 70mm eyepiece.
The Celestron 11 seems to have tube vents near the primary for cooling that let heat out but supposedly don't allow dirt in.

My 12.5 inch Dall Kirkham had a focal length of 4,650mm.
The 50mm would give 95x. I may have tried this to look at M81 and M82 near the zenith.
But the lowest power I used for most observations was about 145x using a very nice 32mm Erfle in 2 inch barrel.

These large planetary scopes are not usually used at low power.

It is indeed important to look at secondary obstruction size.
With the Intes Russian Maksutovs I see that 16% to 33% is mentioned, maybe for visual and photographic uses they differ.
The Skywatcher 180 Pro secondary seems to be about 25%, but I haven't found an exact size.
However, some reports say the ones tested were extremely good on planets.
It may weigh only 7.5Kg?, which may be lighter than the C 9.25 or 150ED refractor?

The Celestron SCTs seem to have f/2 primaries with a 5x amplification.
Except that the Celestron 9.25 seems to be f/2.5 with a 4x amplification by the secondary. It is supposedly almost as long as the C11.

I would hope that a Celestron C11 owner would not stop the 11 inches aperture down to 5 inches by using too low magnification.
But there is a possibility that somebody might actually do this.

I have just found the old notes on Horace Dall's 8 inch Maksutov that we used to view Mars at 400x or more through his attic window. It was as good as they come.
The primary was 8.66 inches diameter and it was f/2.48, which is listed as rather lazy, so the rest of the optics weren't too demanding.
I don't have the secondary obstruction size.
Generally, British made obstructed scopes aimed to have 25% central obstructions or smaller if possible, depending on the illuminated field size.

The 20.5 inch f/3.9 Newtonian primary was indeed 1/20th wave after being tested tested against the 25 inch autocollimating flat, but I don't know how accurate the flat was. So I don't know the accuracy of the 1/20th wave, but I suppose the mirror maker knew. He is the best.

Dudley Fuller of Fullerscopes had a restored red E type Jaguar.

B.

"A wealth of information!" :t:
I've been given many buying tips, but need to consider the need and the budget before taking the plunge.

Where I previously asked about the practical limits rather than the optical ones, and took 200x as a benchmark, I'm now thinking a 150x limit and 1 mm exit pupil. With budget restrictions applied, this points towards a 6" catadioptric telescope, perhaps a Skywatcher Skymax 150.

Before going that route, I'll investigate what the C90 and the ED82A can actually produce and how I feel about the reach at 125x and above.
The 40 degree slice of sea view could indeed be useful and (mostly) comfortable, but 40 degrees is a major restriction, in particular as it faces towards south. Conversely, the panoramic view towards north/northwest, northeast, east and southeast may prove difficult to use because of either back light in the morning or heat shimmer in the evening.

Other than that, and the huge distances, the balcony is well suited for the task. It is 17 square meters and very steady. I do suspect that extreme magnification could be difficult to use when it's a hurricane, because the building will probably sway in the wind. Not really sure.

But I expect a magnificent overview over the rural hinterland, where Harriers, Buzzards, Honey Buzzards, Kites, Ospreys and Golden Eagles soar and migrate.

//L

Hi Lars,
With a 150mm Maksutov Cassegrain at 150x things are much easier, and the window glass may be up to the task.
But the telescope must be tested and must be good.
My 127mm Skymax is rather poor, but the 90mm is very good.
A good Russian 150mm Maksutov may be better but heavier, but still not too heavy.
A secondhand one might be very good if carefully tested.
The tripod must be very sturdy, maybe altazimuth head.

I never had any problem or need to reduce the magnification of the 150mm f/10 Maksutov below 95x, so I just kept the fixed magnification at 95x. Through window glass, open window when suitable, or on the balcony.
The 150mm f/15 Maksutov was quite happy at 150x or 200x, but needed more care to find suitable conditions.
Both were British custom made.

I have actually used or at least tested about one hundred mirror scopes or mirror lenses as scopes terrestrially during the day.
From about 50mm to 317mm aperture.
Distances up to 70 kms.

The weather and atmosphere, Seeing, transparency, lighting and sun direction are far more important than optical quality or theoretical loss of contrast.
But the scope must be good or excellent for long distance viewing.

Personally, I think that 90mm or 100mm scopes are just too small for long distance viewing.

My well built building does move in the wind. I see it by looking at reflections from a glass almost full of water. When a lorry or truck goes by the building moves.
But I doubt this would have much effect on viewing from inside the building, but it could affect the balcony view.
In a hurricane the air movement is likely to disturb the Seeing as much as any building movement.
Perhaps a Canon 18x50 IS binocular would be useful here.
How often do hurricanes occur in Sweden?
I know there are microbursts, which can turn aircraft upside down.

You mention the area of the balcony, but what is the distance from the building wall to the balcony window glass?
This would determine how long a scope could be used.
If it is as big as 3 metres, more or less any size scope could be used up to a 7 inch refractor.

The person who made my 20.5 inch optics said he was making an 8 inch refracting binocular.
I haven't heard the results.

Really, a 150mm Maksutov has no problems, but it should be a very good example.

The balcony is 2.7*6.5 meters. The red marking in the lower right part shows the location of the panes that face towards SW. The actual length of the telescope could well exceed 2 meters, but there will be problems with reaching true SW (Anholt) because when the tripod legs reach the edge, the telescope will be too far from the line of sight. Unless I could cast a cylindrical concrete foundation to replace the tripod right there.

The angle of sight towards S-SW is about 40 degrees, restricted by the own house's wall and the next house.
But the other way is a panorama exceeding 180 degrees from NW to S-SE.

Hurricanes have become increasingly common, and have caused major damages the latter years. Even those coming in unexpected directions, causing damages in places that previously used to be spared. I have seen rocks weighing about 200 kilograms thrown ten meters uphill by the waves. Charts had to be corrected after a stone reef moved ten meters by the Gudrun hurricane.

But I'm painfully aware that the situation is considerably worse in the tropics.

//L