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Hawke Endurance 20x60-85 non-ED vs. Focus Nature 23x70-70 (1 Viewer)

Royfinn

Well-known member
I have not much experience with scopes. We have had Focus Nature scope for 1,5 years. It was 220 € with decent Velbon tripod, worth of 60 €. We have identified lot of nice birds with it. At 23x magnication it has good pic quality, but when you zoom, the pic gets blurrier and blurrier. So zoom gets use only in desperation. FN seems to be well made, focus knob is OK and it weights a lot. So in practice we use only "fixed" 23x magnification like 95 % of the time.

So I read through this forum searching for new scope. It was a toss up between very small scope, or big scope - and maybe I shoud buy something in between... I wouldn't like to spend too much on the scope, but I knew, that cheaper scope propably ends in disappointmet. :-C

Today the Hawke (450 €) was delivered and I took some look through the window, as it's cold and snovy outside. The scope is nice looking, quite big and the 2-way focus knobs feel nice. My first impression of pic quality vs. the FN is that it's not much better. :-C At 20x the view is good, but it gets blurrier with more zoom. I have only snovy landscape to look at, so test environment is not best possible.

I don't know, maybe I am expecting too much, but for now I am in the opinion to return the Hawke, as it's seem not to be much of improvement over FN and it's ever larger in size. In many way the 2 scopes are similar. Now I have to rethink, that maybe I should go for the small scope route...:smoke: or just be happy with decent 23x view the I have.

PS: I have this blackening phenomenon with both scopes... when I increase the zoom and look through the scope from bit further away than optimum ER there appears a blacked area in the 11 o'clock that gets bigger the more you zoom in, covering like 15 % of the circle. :eek!: I thought there was something wrong with FN scope, but the very same thing happened with Hawke.
 

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Binastro

Well-known member
Terve Royfinn,

Lasi ikkuna ehka ongelma.
Not sure if that's right.
I.e. The glass window, double or triple glazed is the problem if you are looking through the glass.
My windows are good enough for 100 times magnification with an 85mm scope, most aren't.

Are you looking through the closed window?
Looking through an open window is probably worse.
Plus 20C indoors minus 20C outdoors.
Massive turbulence of air through window gap.

The blackening problem is I think due to changing eye relief with changing magnification.
Do you wear glasses with the scope?
Even without glasses this could be the problem.

I understand that it has been around minus 30C the last week, and lots of snow. At least in southern Finland. Possibly colder in Jyvaskyla.

Terveisin.
B.

P.S.
Even outside the scope has to cool to ambient temperature if it is minus 20C or minus 30C.
A Swarovski 95mm scope would be poor through poor window glass or through a large temperature difference open window.
I have used a 135mm aperture refractor and 217mm Newtonian and 204mm SCT in an open observatory at minus 25C. Also other optics down to minus 35C outside. But there are problems with ones breath and icing.
Glass can shatter, but probably only below minus 20C or minus 30C.
At minus 40, I don't know, but minus 37C was O.K. for Minolta SR1, Canon FTB and Nikon cameras and lenses.

Maybe find a large sports hall or stadium or another large indoor venue with constant temperature and then test the two scopes side by side.
 
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jring

Well-known member
Hi,

a fast refractor like a spotting scope needs ED glass or fluorite or a triplet objective lens to work at higher magnifications, even if the lenses are perfect (which they seldom are in low-priced offerings).
Around 40x is usually the line where you are starting to feel the effect of longitudinal chromatic aberration even in high quality non-ED scopes - you are hunting for the best focus instead of having the image pop into focus.

If the lenses are non-perfect, which is often the case in very cheap scopes, it can happen that they will only deliver a clear image at 20x - or not at all.

I strongly recommend to return the Hawke and try to find an older, used ED scope from a well known brand, Kowa ED and fluorite models, (type numbers ending in 3 for angled or 4 for straight), Nikon Fieldscope ED models, Pentax ED scopes can sometimes be found in the $500 range, the teutonic alphas form Zeiss, Leica or Swaro are usually quite a bit more expensive even used.

Used optics should only be bought in person after a close inspection or from a reputable business with a good return policy.

Joachim, who still uses a 30 year old Kowa TSN-3 with a modern EP and has not yet felt the urge to get an alpha.
 

Binastro

Well-known member
Royfinn,

If the problem is found to be the window glass, then try different parts of the window, as the quality varies.
If there is triple glazing with a single pane and separate double pane then try to use only the single or only the double pane of window glass.
Again try find the best bit of glass.

If you have several windows try different ones and again try to find the best bit of glass.

Terveisin,
B.
 

Binastro

Well-known member
Hi Royfinn,

Looking at your picture in post 1.
Silmaetaisyys is 17-14mm.
This is I think the cause of the blackening that you notice.
The eye relief changes with magnification from 17mm to 14mm.
 

Royfinn

Well-known member
Terve Royfinn,

Lasi ikkuna ehka ongelma.
Not sure if that's right.
I.e. The glass window, double or triple glazed is the problem if you are looking through the glass.
My windows are good enough for 100 times magnification with an 85mm scope, most aren't.

The blackening problem is I think due to changing eye relief with changing magnification.
Do you wear glasses with the scope?
Even without glasses this could be the problem.

I understand that it has been around minus 30C the last week, and lots of snow. At least in southern Finland. Possibly colder in Jyvaskyla.
I have new triple glazed windows, that are quite dirty... I not sure how much they make view worse. Yesterday it was really cold.

I don't wear glasses with scope, althought I have mild Glasses. ER with both scopes is not very good with glasses. The blackening problem is kind triangle at 11 o'clock that goes bigger as I zoom more. It goes away, if I press my eye wery close to lens.
 

Royfinn

Well-known member
Hi,

a fast refractor like a spotting scope needs ED glass or fluorite or a triplet objective lens to work at higher magnifications, even if the lenses are perfect (which they seldom are in low-priced offerings).
Around 40x is usually the line where you are starting to feel the effect of longitudinal chromatic aberration even in high quality non-ED scopes - you are hunting for the best focus instead of having the image pop into focus.

If the lenses are non-perfect, which is often the case in very cheap scopes, it can happen that they will only deliver a clear image at 20x - or not at all.
Yes, it seems that there are none cheap scopes to deal with 20x60 magnification. Not sure, where the line of price for good 60x magnification goes...
I strongly recommend to return the Hawke and try to find an older, used ED scope from a well known brand, Kowa ED and fluorite models, (type numbers ending in 3 for angled or 4 for straight), Nikon Fieldscope ED models, Pentax ED scopes can sometimes be found in the $500 range, the teutonic alphas form Zeiss, Leica or Swaro are usually quite a bit more expensive even used.
Returning Hawke might be best solution, as the size might be a slight problem and the view is quite narrow. Market for used scopes is quiet here in Finland, I think.
 

Royfinn

Well-known member
Hi Royfinn,

Looking at your picture in post 1.
Silmaetaisyys is 17-14mm.
This is I think the cause of the blackening that you notice.
The eye relief changes with magnification from 17mm to 14mm.
Yes, that's the Eye Relief of FN scope. The black triangle don't show itself, if I press my eye to the scope, but I rather keep bit of distance in higher magnification for not to move the scope. I can see the center of view, but an extra black triangle at 11 o'clock don't make using higher magnifications very inviting, as the scene is blurry even without it. 3:)
 

Binastro

Well-known member
Hi Royfinn,
The fact that your triple glazing is dirty is not the problem.
That will slightly darken the view and may reduce the contrast.
The problem is three layers of glass.
In addition they may be coated to reduce heat loss.

Also the larger the scope the worse the definition becomes due to rather poor quality glass.
You may get better results through triple glazing by making a 50mm mask over either scope to reduce the aperture.
If you have a side opening window that only leaves one pane of glass between inside and outside it should give better results.

Even if you had the very best quality scope, 3 rather poor glass layers will give poor results.

If you open the windows with plus 20C inside and minus 20C outside the view will be terrible.
One solution would be to have an observing room with no heating at all. This will reduce the temperature gradient if you open a window.
Clear Mylar over an open window may give good results.

With good quality windows the boundary layer of air outside a closed window should not be too troublesome, even with a large temperature difference between inside and outside.

Indeed, a better scope say a Pentax ED, Kowa etc would do better.
But I would expect a good Hawke 85mm scope, even non ED, to give good results at 60x in good steady temperatures.

You really should test either the two scopes you have or any new one in a constant temperature large hall, shopping mall or stadium or wait till the temperature is well above freezing, before you judge a scope's performance.

I am pretty sure the blurry view is mainly down to 3 layers of window glass and big temperature gradient. Also partly due to rather average scope performance.
Even outside the view may be compromised at minus 20C.
 
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jring

Well-known member
Hi,

I agree that triple glazing will degrade the view - to what degree really depends on a lot of parameters. In my case, the double window in my bedroom works fairly well up to 60-80x if the scope is more or less orthogonal to the window pane. In the living room a seemingly identical window fares not so well... even with the heating turned off (the bedroom heating is on quite rarely anyways).

And as Binastro has stated, just opening the window will not help unless the the room is at outside temperature.

If the scopes were only tested under these conditions, a quick test in the cold would be helpful to decide if it's the windows or the scope...

Regarding a non ED scope at higher magnifications - I met a fellow birder with a TSN-1 once, the plain glass brother of my fuorite TSN-3 once and we did some side by side comparisons with different EPs. The result was that at around 40x the TSN-1 started to get difficult to focus exactly and was visible soft at 60x. She really wanted to get a 30 wide EP instead of her awful old 20-60 zoom from the 80s afterwards...
This is physics and cannot really be changed without ED glass or a triplet objective lens at those fast focal ratios of f5 or f6.

Joachim
 
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Binastro

Well-known member
A quick test in the cold may not help much as fast refractors are affected quite a lot if cooling fast.
On a warm day, say minus 5C in Jyvaskyla, 20 minutes outside should see the scope stabilise, before misting begins.

Better, I think, is to go to a school large sports hall and look at a newspaper at the other end of the hall, and compare the two scopes.
Allow 30 minutes for scopes to warm after minus 20C outside.

Some windows in Finland are two windows that open separately with a large air gap between the two windows.
If one can have the one with a single pane closed this should improve the view compared to three layers of glass.
 

Royfinn

Well-known member
Decided to go Nikon ed50 way...

I returned Hawke scope. I don't know, it was just too big and comparison to my old scope didn't look promising enough, but I didn't test Hawke properly, so it's left open, how good it actually was.

I have Nikon p900 camera, which is great in birding and we took over 100 000 pics with it last year. :t: Also I am happy with the Nikon Monarch 7 8*30 bins, so why not to go forward with the Nikon route...

First test show that it is sharp and it "snaps in to focus" easily, so it might be good and not a "lemon". I order it from Amazon Japan and it was about 460 € including 27x eyepiece, taxes and postal costs. In Amazon.uk it would have cost way over 800 €.

I also ordered 65 € Rangers tripod to use with ed50. There is million tripods to choose from, but I wanted one that fits well in my backback. Hope that it's sturdy enough and maybe I change the ball head if I am not happy with it.

https://www.amazon.de/Tragfähigkeit...qid=1550164677&sr=1-1&keywords=rangers+tripod

I read through every post about ed50 here... :-O There are lot of different opinions. Some say that 16x eyepiece is way to go and that 27 is too dim and uncomfortable. Others say that 16x is not enough magnification compared to binos. Some say that in 90 % of viewing ed50 is nearly as good as "the big boys", others say that "it's ridiculous how much better view the 65mm swaro has compared to ed50".

At first glance ed50 seems to be bright enough. The ease of view is not as good as with my old 70mm scope. Biggest advantage with ed50 is portability, as my old scope has been used as 23x "fixed" and the view is similar. I have to test scopes against each other when I get my second tripod from amazon.

I thought seriously buying Vortex razor 50mm or Opticron mm4 60mm, but the Amazon Japan prices were the deciding factor.
 

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