What is ergonomics in  astronomical telescope ?

 Astronomical telescope is used to see very large area in  the sky .The difference between the astronomical use telescope and the one for landscape viewing is this .
  In most cases current astronomical telescope force user to look through in a  painful pose .
 I think it is very important to design the astronomical telescope considering the human body . Because the telescope is the machine used by human .

Conditions of the ergonomics on the astronomical telescope .

Easy to look through in a comfortable position
 Basically we feel pain to bent our neck to see the sky at the altitude angle of  over 60 degrees .
 When we watch around the zenith , we have to throw back our head , strength the our back born , bent the neck hard .Very hard .
 That is the reason why we must use a refractor telescope with a diagonal prism .
 To see the zenith with our neck which is possible to be bent only until 60 degrees , we should give an incline of over 30 degrees between the viewing direction of the telescope and  the eyepiece axis. (90-60=30)

the principal of incline the eyepiece
Because the neck of human body is not able to be bent over 60 degrees ,
the eyepiece direction must be bent for over 30 degrees .
 It is easy to look through the newtonian reflector because it has 90 degrees incline at the eyepiece already .
 We also feel some comfortable to look through astronomical binocular telescope when compared with the  straight through telescope because many of them have 45 degrees inclined eyepiece .

 We must not forget the significance of the height of the eyepiece .  We can't avoid the pain with the inadequate height of the eyepiece even if it has an incline of some degrees .

 When we use the 45 degrees inclined telescope at a hinge consist of one shaft , the height of eyepiece vary a lot .It exceed the allowance of human body .
  If we set the height of eye piece position to be able to look through the landscape , it goes down too low to look through comfortably when we see the upper sky .

this is so hard !
The sample of the worst situation when considered human engineering

 It is necessary to increase the height of eyepiece according to the rise of the altitude angles of the telescope ideally .

Capable to feel actually  the derection where the user watching
 We must think about this condition considering the above condition .

 When I talk about ergonomics in  telescope , some always point out that there are the coude types of which the position of the eyepiece don't move or the type Yamazaki of which the eyepiece position is set in the shaft of altitude bearings already .
coude coude type yamazakiyamazaki type
 It is true that it is easy to look through those types of which the eye piece position isstable . But user can not feel actually where he watch because there is no relationship between the directions of the eye piece and the telescope .
easy but
Where am I looking ?

 The CCD camera will be used more widely in the near future which is not necessary to look through the eye piece any more .So those types with computer control system may not  be so odd in the future  .
 But I think those types are not so human . The real ergonomical telescope should give user a feeling to know where he see naturally .
 It must have the static relationship between the the viewing direction and telescope axis .
 Regarding this condition the straight through pass type is the best . But this type is not easy to look through in the sky as I explained in the above condition .
 As this condition and the above one are opposed each other so I propose following sub conditions as compromise .

- The incline of the eye piece against objective axis is below 60 degrees
- Make something like a site line near eyepiece
- Make it possible to get wide field view at low magnification ( If possible over 3 degrees )

Erect image
 The up side down image of astronomical telescope is the result not to degrade the optical performance .
 Of course the erect image like such as binoculars is more natural .
 User will get used to the movement of the inverted image of the current telescope . But he must see the star map up side down in the dark night with small red light .This will make him confused sometimes .
 The mirror image of the diagonal prism ( or diagonal mirror ) is more odd than inverted image . You can hardly contrast the image with the map or with real star pattern by your bear eyes  .

you may do this
the way to get right image ?

Light weight
 The heavy mounting is more stable and more effective to keep the telescope away from vibrations .
 But many of amateur astronomer must bring his telescope out of his house to the near  dark open space or into the car .
 There is the limitation of the weight that human can hold .
 If the total weight is over 10 kg ( 4.5 pounds ) , you will be tired to move it to the near park unless you pay attention to the way to hold it .
 If the total weight is over 20 kg ( 9 pounds ) , it is necessary to transport it on a handcart properly speaking .
 The weight of the easy use telescope must be less than 15 kg ( 6.8 pounds ), if possible , below 10 kg (4.5 pounds )  ideally .

Easy to construct
 If the telescope is not be able to be in use soon the user will lose his passion to use it .
 It is not easy to construct many parts at the night .
 The telescope should be constructed by only transformation identically . It is not good to assemble the separated parts in the dark .
 The user must give up to assemble his telescope if he dropped the screw in the bush at night .

light , easy ,quick

Nice viewing
 This condition does not mean a mere optical or mechanical performance of the telescope but the psychological expectation .
 That is "How does this telescope gives the user fun to use ?" .
 For examples , If it takes 15 minutes to assemble the 2.4 " telescope ,the user will be disappointed by it's poor performance .
 But if 12" performance telescope require 20 minutes to be constructed ,the user will admit it .
 This condition should be called labor performance or so .

 If the telescope have a obvious possibility to hurt user ,it is disqualification .
- Eliminate dangerous section ; sharp edge , bare screw ,etc.
- Safety warning indications ; Never see the sun , the way to hold , high voltage , etc.
- Not easy to fall down
- Not easy to lose the cap of objective lens . ( to avoid the accident by the sun light in the day time . )

 These ergonomic conditions for telescope are difficult to be satisfied with all at once on a telescope . Because some of theme  are opposed each other .
 I think current style of the telescope sold in the market is one solution made from  many try and error by our great elders .
 Thanks for them ,we can buy good telescope at the reasonable price today .
 But I think that there are many who want more human telescope . ( I am one of them )
 Recently some people reported their studies about ergonomics in astronomical telescope like below

They are studying the ergonomics in the telescope or binocular
Mr.Miyag ....bench for binoculars (HP linked)
Mr.Tatsuro Matsumoto ...invented the erecting mirror system (HP linked)
Mr.Youichi Kimura .....many report about ergonomically optics for astronomical binoculars
Mr.Kunio Takagi ....invented erected mirror system for ordinary binocular
Mr. MItsuji Kaneko ....invented personal capsule type telescope
Mr.Tadasi Kato ....invented mounting for astronomical binoculars
and  Hiroyuki Yamaguchi.....it is me

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