First light: Takahashi Abbe Ortho 25mm, Nikon NAV 7SW

[YKSE]

Got some minutes among the cloud with these two, not great seeings, SQM around 18.

TAO 25mm was tested in C8, comparing with MV 24mm, with/without VIP 2x barlow, also with BCO 18mm barlowed 1.3x; while Nikon 7mm was in 80ED, comparing with BCO 10mm barlowed 1.3x, and BCO 6mm.

TAO 25mm:

The eye cup was indeed very helpful, easy for eye placement, no blackouts, no stray lights on eye lens, sharp field stop

M42: quite low already, just over neighbor's house, TAO showed just tad more nebulosity, a little clearer fainter stars in FOV.

Jupiter: Clearly less scatter than MV24mm, GRS better defined, noticeable more detail in the SEB and NEB shown in TAO, with/without barlow. Scatter was also less than barlowed BCO 18mm, a tad more detail on GRS and the bands.

M37: Just framed in TAO, nice star field, some fainter stars seen in averted vision in MV could be seen in direct vision.

M3: More stars resolved than MV24 in barlowed modd, the globular felt brighter in barlowed TAO and barlowed BCO.

Nikon 7mm:

Very flat field, pin point star across the field of view, no astigmatism, comfortable ER, no stray light on eye lens even without the eyecup, no ring of fire or edge brightening.

Jupiter: very good stray light control, with Jupiter just ouside FOV, stray lights were barely visible. Noticeable more scatter than barlowed 10mm BCO, just barely more scatter than 6mm BCO. color rendition was neutral as the BCOs.

That was all I managed this session, the summarized impression is that TAO is as good as I hade hoped for, while Nikon's flat field and no edge brightning are positive surprises since there were some comments on that. I need to look harder for it next time.

[John]

Thanks for the early feedback Yong

The BCO's are a good yardstick to compare with.

[YKSE]

A couple for pictures to show the coatings:

Takahashi: same dark coatings no matter viewing straight or from side

Nikon: Straight view

from side

In observing, Nikon seems to be a little more fussy than Tak in eye placement, the flare on the edge will be very strong when not looking quite on axis into the eye lens. There's no flare or edge brightening though once eye placement is about right.

[jetstream]

Great report Yong,glad you had a chance to try them.I am particularly interested in the Tak ortho performance,they are sounding really good.Hopefully the weather co-operates for some more testing over there.

[John]

Looks like Tak have done what I wish Astro Hutech and Fujiyama had and recessed the eye lens enough to allow the eye to rest gently against the rubber eye cup when at the correct viewing distance.

I contacted The Widescreen Centre about the Tak orthos a few of weeks ago and they had not heard of them, despite being a Tak dealer. It would be good if we could have a UK distributer for these.

[jetstream]

I wish you could get the whole set to test John,side by side to BGO,Fuji's with your 120ED and 12" OOUK dob

[John]

I wish you could get the whole set to test John,side by side to BGO,Fuji's with your 120ED and 12" OOUK dob

Just need to find a co-operative Tak dealer Gerry 

While they are at it, they may as well send me a Tak TOA 130 to try out as well !

[Pig]

Thank you for taking the time to write the report yang, very informative

[YKSE]

Looks like Tak have done what I wish Astro Hutech and Fujiyama had and recessed the eye lens enough to allow the eye to rest gently against the rubber eye cup when at the correct viewing distance.

John, your comments there on 25mm are one important reason I got interested in the TAO 25mm, the other reason is blind faith in Tak's quality

[YKSE]

Here's some measured physical data for these two eyepieces without dust caps, if it is of interested for someone:

Make                           Weight(g)                    Length(mm)                             Biggest diameter(mm)

Nikon Nav 7SW              320                               82                                              56

Tak Abbe Ortho 25        160                               74                                              38

[alan potts]

Nice report, Yong, the Nikons sound nice and the taks seem to have found favour with John for the design, I wonder if they are hte same, guess buy one and find out is the answer.

Eyeplacement can be difficult on a good few eyepieces when you just buy them, a few months from now you will wonder why you said it.

Alan.