Jaegers achromats versus Chinese achromats
Barry Simon
varieties) typical of any good achromat or are there verifiable
differences between the Chinese achromats and older achromats
available to the amateur astronomer ten or more years ago?
Specifically I would be interested in hearing from anyone who has some
first hand experience viewing thru a good example of a Synta 6" f/8
achromat and a Jaegers 6" f/8 achromat. As an owner of a Jaegers 6"
f/5 achromat, I am well aware that a short focal length achromat does
have a significant amount of chromatic aberration associated with it.
In my particular telescope this is very evident around brighter stars,
Jupiter, Venus, and the limb of the Moon. It is however not a real
problem with visual observation of virtually any other object. I also
find that chromatic aberration in photographs of deep sky objects can
be "corrected out" pretty substanially with a Lumicon Deep Sky filter.
Any experience out there in comparing the two named achromats?
Barry Simon
Chris1011
I owned an F10 Jaegers many years ago. Tests showed it to be corrected to 1/10
wave P-V. One of my friends had a 6" F15 Jaegers, and its correction was closer
to 1 wave P-V with lots of zones.
Jaegers had a large turnover in personnel, so the optical quality depended on
just who was working there at any given time.
Roland Christen
miroslav
I shall reply bellow message.
miroslav
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miroslav
refractors for visual estimates of variable stars.
The Jaegers is better optical telescope
permanently mounted in light-poluted city,
Synta is used as portable telescope giving
amazing results in dark sky enviroment.
Difference is not really that big but it is there.
Jaegers is optically better!
I guess I was lucky with my Synta OG optically.
Recently I was observing Venus, Mercury and
Jupiter (alignment of planets) with my Synta
stopped down to 100mm (4"), TV Big barlow
front of Ever Brite diagonal and Pentax XL
eyepieces with absolutely stunning results.
The moons of Jupiter were seen not only
different brightness but different sizes,
Mercury as very sharp crescent......
Also 150f8 Synta stopped down to 100mm
with Bader solar filter and UO 18mm ortho
eyepiece does show complete Sun disc with
sunspots unbelievably sharp....
miroslav variable stars observer
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jerry warner
wave and would hardly resolve the Tarpezium until a very
clear night. In a word it's plain "muddy".
My friends 6" f/5 is easily better (1/6-1/8th) and even with colour had better
overall resolution which was hard to believe. Another 6" f.5 I know is at least as
good as my friends. Our club 6"
f/5 is very good except for colour, much better than the 6"
f/15 in quality of otpics.
My old 6" f/10 was superb and would easily beat our club's 6" f/15 today, which may
account for what I think I have noticed: 6" f./10 Jeagers prices usually go a bit
high without much haggling and sell very quickly. Some 6" f/15's you cant give
away.
Jerry
Tom Mack
> Specifically I would be interested in hearing from anyone who has some
> first hand experience viewing thru a good example of a Synta 6" f/8
> achromat and a Jaegers 6" f/8 achromat. As an owner of a Jaegers 6"
> f/5 achromat, I am well aware that a short focal length achromat does
> have a significant amount of chromatic aberration associated with it.
> In my particular telescope this is very evident around brighter stars,
> Jupiter, Venus, and the limb of the Moon. It is however not a real
> problem with visual observation of virtually any other object. I also
> find that chromatic aberration in photographs of deep sky objects can
> be "corrected out" pretty substanially with a Lumicon Deep Sky filter.
>
> Any experience out there in comparing the two named achromats?
>
> Barry Simon
Barry,
It was Clyde Tombaugh who inspired me to buy a Jaegers 5 inch F/5
Achromat back in the early 70s. He wrote "the sights through this
instrument are truly marvelous, especially at Flagstaff where the
nightsky is very transparent...visiting astronomers as well have
looked through the short-focus 5 inch and can vouchsafe for the sights
described". The 5 inch was a cemented achromat and with a 2.7 inch
military erfle and was a great RFT. Aperture fever hit and I then put
assembled a 6 inch F/5 Jaegers. This lens was airspaced and also had
geat deepsky views despite obvious color on bright stars. I thought
the quality of my particular lens was even better than the 5 inch
Jaegers though back then it seemed amateurs were not as concerned with
star testing and optical quality because the choice of scopes was
limited. Questar and Tinsley were the leaders in optical quality but
very few could afford them.
As for comparison with the Chinese achros today, I thinks in general
the Chinese lenses may be just a tad better than the older Jaegers.
One reason is that the Jaegers lenses were all coated with Magnesium
Flouride while the newer Chinese lenses have a much more effective
multi-coating. The Chinese lenses are also all machine polished and
if the optician makes sure the polisher is maintained you get
generally production lenses that are similar in quality and do not
vary in overcorrection or undercorrection by too much. 1/4 wave
accuracy is not to difficult to achieve with machine polished lenses.
By the way when I bought the components for the 5 inch refractor the
price was as follows:
Lens: $85
Lens Cell: $22.50
tubing: $6
focuser: $27.50
WA Erfle: $22.50
I wish we could find those prices today.
Cheers,
Tom Mack
Richard
Well, you can buy a Chinese 5" f8 today for $149 dollars in a cell
which is about 4x cheaper (accounting for inflation) than the Jaegers
cost back when.
Tubing? Cheap if you find it. Focuser, they cost more though,
but you can buy the Chinese ones for $64.00 2". Erfle? Around
$75 but you can buy a Plossl for about $39.00.
Sounds to me like scopes and their parts cost a LOT more back
then than now.
-Rich