Tak vs Tak

[Stu]

3 minutes ago, jetstream said:

Stu, I'm curious what diagonal you were using as well, did you have the Baader/Zeiss prism out?

Yes Gerry, T2 Zeiss so I don't think I can blame that . I did have the Everbrite unit too, tried both.

[jetstream]

Well I think we can eliminate the diagonal then, those are both top notch. Honestly I've noticed how eyepieces interact with my scopes, refractors included even when the eyepieces used are all proven and "good" ones. Possibly the eyepieces used are a factor?

 

[John]

3 hours ago, mikeDnight said:

..... Daniel Mounsey, also on CN and who's tested many of the new FC100's, did imply some inconsistency in some of the figuring. After testing several FC F7.4's alongside several FC F9's he found two of the F9's not to be as well figured as the F7.4's under test. However, I seriously doubt Takahashi would allow a poor lens through the net. Himoru pointed out that in the 90's, Takahashi trashed 50% of the fluorite lenses that Cannon supplied as being substandard, showing their insistence on optical perfection....

 

Daniel promised a full report ages back but still hasn't posted it

With just 100 DL's being produced over a 2 year period I'd not have thought that quality control would be any issue at all for a company so geared up for it as Takahashi. They got a bit of flack for limiting the production run so I'd have thought that they would not risk any inconsistency in optical quality.

The coatings have the brownish tint on my DL BTW. Maybe Gavster's F/7.4 was from the 1st run of the new FC series ?

My working assumption, until demonstrated otherwise, is that the F/7.4 and F/9 wouldl be equal performers in terms of optical quality. I wonder if you ran through the same tests on another night the results would be different ?. I've seen that when testing eyepieces that are very close in performance.

[Stu]

Next time we can perhaps be a little more rigorous and try to get the two setup as close as possible to the same spec. We both have Zeiss Prisms and Gavin has two Leicas so we can dial in the same mag on various targets.

EDIT I have a pair of 15mm SLVs and a pair of Zeiss Orthos but we are left with the mag difference. We can play with BGOs of different focal lengths to get close though e.g. A 9mm in the f9 and 7mm in the f7.4 will be about the same

[mikeDnight]

4 hours ago, Gavster said:

Mike,

Your comments got me checking my DF and DL just to make sure and my DF definitely has a green coating (the differing coatings between the DF and DL has been mentioned on CN before). See the attached photo which hopefully shows this - DL on the left. I admit I didn't specifically check Stu's coatings (?) the other night but just assumed it would be green like mine. My DF was an early one so maybe it's just that tak has updated the coatings in all the d series and my comments about a difference there are a red herring. Sorry. I'm interested to find out what colour Stu's coatings actually are though?

Thanks for that Gavin. The mystery deepens! 

Mike

[mikeDnight]

1 hour ago, John said:

Daniel promised a full report ages back but still hasn't posted it

With just 100 DL's being produced over a 2 year period I'd not have thought that quality control would be any issue at all for a company so geared up for it as Takahashi. They got a bit of flack for limiting the production run so I'd have thought that they would not risk any inconsistency in optical quality.

The coatings have the brownish tint on my DL BTW. Maybe Gavster's F/7.4 was from the 1st run of the new FC series ?

My working assumption, until demonstrated otherwise, is that the F/7.4 and F/9 wouldl be equal performers in terms of optical quality. I wonder if you ran through the same tests on another night the results would be different ?. I've seen that when testing eyepieces that are very close in performance.

I may have got confused with a post by Bill P! 

Mike

[mikeDnight]

1 hour ago, Stu said:

Next time we can perhaps be a little more rigorous and try to get the two setup as close as possible to the same spec. We both have Zeiss Prisms and Gavin has two Leicas so we can dial in the same mag on various targets.

EDIT I have a pair of 15mm SLVs and a pair of Zeiss Orthos but we are left with the mag difference. We can play with BGOs of different focal lengths to get close though e.g. A 9mm in the f9 and 7mm in the f7.4 will be about the same

That was the difficulty I had when comparing my DC with a friend's Vixen FL102. We couldn't quite match the magnification. The result was that in reality, both scopes were superb performers on Jupiter and Venus, but there were slight differences in image scale. The FC appeared to me to be a bit richer when it came to revealing colour in Jupiter's belts, but the difference was subtle. Although two other observers claimed they prefere the Tak, I can't help but feel it was because it was a Tak, and they expected it to have the edge. Personally, I could have walked away with either scope and been perfectly happy. ? I have a major soft spot for the Vixen as it was the first fluorite I'd ever seen through many years back, and it changed my life!

Mike

[mikeDnight]

4 hours ago, Gavster said:

Mike,

Your comments got me checking my DF and DL just to make sure and my DF definitely has a green coating (the differing coatings between the DF and DL has been mentioned on CN before). See the attached photo which hopefully shows this - DL on the left. I admit I didn't specifically check Stu's coatings (?) the other night but just assumed it would be green like mine. My DF was an early one so maybe it's just that tak has updated the coatings in all the d series and my comments about a difference there are a red herring. Sorry. I'm interested to find out what colour Stu's coatings actually are though?

I've just found a couple of old pics of my DC lens. Perhapse not the best reflections but hopefully shows the coffee colour.

Mike

 

[John]

40 minutes ago, mikeDnight said:

I may have got confused with a post by Bill P! 

Mike

No, it was Daniel Mounsey. He has posted one or two teasers over the past few months about these comparisons that he has done but has yet to post anything substantial on them. I detect a little frustration in some of the posts on this on CN !

 

[mikeDnight]

7 minutes ago, John said:

No, it was Daniel Mounsey. He has posted one or two teasers over the past few months about these comparisons that he has done but has yet to post anything substantial on them. I detect a little frustration in some of the posts on this on CN !

 

Thanks John. I haven't completely lost the plot then! ?

Mike

[Stu]

58 minutes ago, mikeDnight said:

I've just found a couple of old pics of my DC lens. Perhapse not the best reflections but hopefully shows the coffee colour.

Mike

 

Mike, mine looks like that when viewed at an angle, but the reflections are actually green like Gavin's. I'll post pictures soon!

[Stu]

Here are pics of mine. Definitely green reflections. Looks like it needs another clean though