so who is gonan buy this

[MooEy]

http://www.telescope.com/shopping/produ ... ord=ED+100

~MooEy~

[Airconvent]

i would say wait for vincent snr....he will buy it , test it and then sell it off.
give him about 1-2 mths!
the 100mm offers about 50% more aperture than my ED80 but cost almost twice as much! Is it worth the extra cost?
I also noticed that the scope is quite long. My guess is the optics alone can't achieve the desired degree of "apo" , so they gave it a longer focal length to help it along its way...anyone can confirm this?

rich

[MooEy]

this scope isn't really that long. the televue 102 is f/8.6, the stellarvue's is f/8.8. even the tak is f/8. only slightly longer.

~MooEy~

[kayheem]

this scope isn't really that long. the televue 102 is f/8.6, the stellarvue's is f/8.8. even the tak is f/8. only slightly longer.

~MooEy~

Portability is relative. Just to put it in perspective, the focal length is 900mm. With the dew shield and focuser in place, it would hit about 1m in length.

Just ask yourself if you would like to carry a 1m tube around and if it is easy to find a bag or case to carry it around in. Some would find it OK, some would find it cumbersome to take public transport with it.

Kay Heem

[weixing]

Hi,

My guess is the optics alone can't achieve the desired degree of "apo" , so they gave it a longer focal length to help it along its way...

If you look at the doublet APO scope in the market, most of them have F-Ratio around F8. I think this may be cause by the fact that in-order to achieve the "APO" using doublet, they have to make the focal length longer. And by making the focal length longer, they also save cost, because lens with shorter focal length is more difficult and expensive to manufacture than lens with longer focal length.

Anyway, I think any 4" and below refractor with a length of around 100cm should still be quite portable.

Have a nice day.

[ariefm71]

if portability, cost, and apo performance is your criteria, better get an intes mk67 (some even compare it with 5" premium apo, but i think 4" is more like it). Vince, if you're buying this 100ED, can you do a comparison review with my intes?

cheers,
arief

[weixing]

Hi,
If this APO refractor is well made, it should be able to give a better contrast on low contrast portion of planet and nebula, give a wider FOV on low power and also give a "cleaner" view than your INTES MK67, but the image will not be as bright as your INTES MK67 or show as much details. The advanage of refractor is the ability to give better contrast on low contrast surface and also a "cleaner" view than other telescope design of similar or slightly larger apeture.

Have a nice day.

[MooEy]

Portability is relative. Just to put it in perspective, the focal length is 900mm. With the dew shield and focuser in place, it would hit about 1m in length.

Just ask yourself if you would like to carry a 1m tube around and if it is easy to find a bag or case to carry it around in. Some would find it OK, some would find it cumbersome to take public transport with it.

Kay Heem

can't measure that way. at any rate we have to remember about 16cm of the scope's focal length is hidden in focuser draw tube, diagonal and eyepiece. a scope doesn't need it's full focal length of 900mm, putting a eyepiece into the back of the scope usually cut the distance by 4-5cm. that's y most camera will need extension tubes, whereas the focused position eyepieces are more inside.

so that means the china apo may have a length of maybe 80-90cm, still way too cumbersome for bus transport.

http://www.stellarvue.com/102v.html
an interesting 4" f/8 doublet apo is the sv 102v. dew shield retracted with the binoviewer configuration, the entire scope only measures 22" long, which is about the same as my 3" refractor.

~MooEy~