More orthoscopics ....

[John]

I've just picked up from another forum that Takahashi are to introduce a range of Abbe Orthoscopic eyepieces. Here is a link to the Takahashi web page but it's in Japanese:

http://www.takahashi...ws_ts-abbe.html

Reports of the demise of this design not too long ago seem to have been a little premature

If the price in Yen is to be believed they could be around £70-£100 per eyepiece.

You don't see many 32mm orthos around !

[Dunkster]

Sounds like the good times continue for orthos

Google translate gives a mostly readable version... some interesting points (I post these blindly!), but I appreciate much of this will be par for the course for you more experienced ortho junkies

• High performance, low cost eyepiece
  
• 4 lenses in 2 groups, 1 + 3 (cemented) Abbe type, no Smyth lens
  
• Good results and nearly flat field with their 2x Barlow
  
• Good contrast, reduced flaring and low ghosting across the field of view with air surfaces (4) all multi-coated
  
• Short eye relief, rubber eyecups to prevent stray light, foldable for eyeglasses(?)
  
• Narrow field of view at 44 degrees
  
• Parfocal ("shift of focus is negligible")
  
• Good for double stars with large differences in intensities
  
• and high magnification for planets and especially the Moon
  
• 9, 18 and 32mm available August 1st, the rest "coming soon"
  

[alan potts]

I was using the orthoscopics last night in the 180 Mak, the 12.5mm Hutech was very nice. I am not sure I see the point of a 32mm ortho, I mean most people use these as planetary eyepieces, there not really a low mag wide field dish, or am I missing something? I think I would buy one though as a sharpness benchmark for the 31mm Nagler

Dunk,

No mention of buy 2 get one free?

Alan.

[John]

I was using the orthoscopics last night in the 180 Mak, the 12.5mm Hutech was very nice. I am not sure I see the point of a 32mm ortho, I mean most people use these as planetary eyepieces, there not really a low mag wide field dish, or am I missing something? I think I would buy one though as a sharpness benchmark for the 31mm Nagler

Dunk,

No mention of buy 2 get one free?

Alan.

I have the 25mm Astro Hutech ortho to try out at the moment. I've not really been able to give it much of a chance yet but the quality seems entirely comparable with the others in the range. Some folks feel more comfortable with low glass eyepieces for DSO viewing although I reckon modern glass and coating technology allows multiple lens units to compete with the simpler designs on light throughput these days.

Alan, I think sub £100 is the Takahashi equivalent of "buy 1 get 1 free" !. Many folks would expect these to be much closer to £200 apiece with the Tak branding on them.

[Dunkster]

No mention of special offers sadly Alan, but then it's been a few years and my Japanese is a little rusty

Seems like a full-on assault on our wallets these days

[alan potts]

It will interesting to see what John has to say about the 25mm Ortho. With regards to light through put on eyepiece I was reading something somewhere the other day claiming the Pentax XW range had a through-put of 98%. I don't know where the figure came from but I think it was on Cloudy Nights. If that is correct then I don't really see it makes any difference as to a smaller amount of glass in the barrel of an eyepiece, it would be impossibe to detect with only an eye.

It would be nice to have some up to date data on this subject because without measurement by nachines we don't have it is only subjective.

I have to say I rather like the orthoscopics and I didn't think I was going to after Ethos fever. I guess the the 25mm and the 32mm have no issues with eye-relief either. I might just add to my little pile.

Alan

[John]

Pentax publish light transmission data. Here are the XW's

http://pentaxplus.jp/archives/tech/xo-xw/63.html

[Dunkster]

Thanks John - that's an interesting read. Does anyone else publish similar data?

[alan potts]

Thanks John, Thats interesting though unlike Dunk I can't read Japanesse. It was not exactly what I thought I read but 96^ or near on is mighty impressive.

Alan.