Highburymark

Think it’s worth repeating here that you have to pick features with small details - intricate structures within craters for example, or the definition of minute craterlets, and study them - swapping between eyepieces, to see the differences I saw last night. It’s the final 5% that the specialist eyepieces provide - clear, but at the margins.

Well I finally had a chance to test the XO 5mm properly on the Moon this evening. I was studying craters around Mare Humorum - Gassendi, Vitello and Doppelmayer in particular. Scope was TSA-120 - XO gave 180x. Very simply, it was outstanding. Sharpness and detail clearly a level above my two other excellent 5mm eyepieces - Pentax XW, and Kasai ortho. But how did the XO match up to the TOEs? It’s very difficult to compare a 5mm eyepiece with a 4mm, but I’d say the difference between the XO and XW 5 was at least comparable to that between the Tak TOE 4 and Delite 4 (much as I love XWs and Delites, no complex widefield EP can compete with these specialist planetaries under good conditions), so moving from XO 5 to TOE 4 and 3.3 felt like a natural progression - the TOEs certainly are not outclassed by the XO. But I would not be surprised if the XO shows just a bit more detail when I experiment with the Tak extender 1.5x and other barlows - so can match magnifications better. Of course there is a price to pay - the XO is not the most comfortable EP with a manual mount (I have the Skytee 2). The minuscule eye relief wasn’t an issue though - I just hover above, even if I can’t see the field stop. Just means lots of slo-mo adjustments. But it was worth it….

Fantastic - thanks for posting the catalogues - looks like you got a very good deal with the DC. The OTA alone was around £1750 in 2016/17 when I got mine. So the 5” FS was more than double the price of the 4” !! Back in those days I only had a 4” Maksutov, so wasn’t aware of the more exotic end of the market.

Thanks Mike - wow, quite a bit more than I thought. So probably around £3.5k without accessories. How much would that be today? At least £4.5k - significantly more than the £4k TSA-120. Sadly I think the FC-125 will remain a dream.

Very nice….. In relation to the potential cost of a future FC-125 D, can anyone remember the new prices of the FS-128 and FS-102 when they were being produced?

I’ve had Delos 10, Delite 11, Nagler T6 11, Ethos 13 and Morpheus 12.5 over the years. Optically, I’d put Delite and Delos marginally ahead of the others, very sharp and bright, aberrations superbly controlled in my scopes, though they are all top notch. I really liked the 11 Nagler, though unfortunately it’s been dropped from the range now. Many other people rate the 13mm as the best T6.

My thought too 👍. My three diagonals are all T2 Baaders - Zeiss prism, Amici prism and BBHS mirror. I swap them around so sometimes am not even aware of which I’m using. The Zeiss prism does show slightly less scatter on bright objects, but they are all very close. The Amici is superb - highly recommended if you prefer lunar binoviewing to present a correct image.

You had me fooled for a second Mike……Much as I would love a 120/125mm FC - presuming it would be enough of a weight saving over the 6.7KG TSA-120 - I don’t think it would make sense financially for Tak considering the 100 DZ is now almost £3k. What would another 25mm of aperture add to the price? It would cost almost as much as the TSA. Maybe if they killed off the TSA-120, so a 125mm DZ could challenge Agema for best 5” fluorite doublet, and that would leave the TOA as the only Tak triplet?

Gerry - if you put that Zeiss zoom up for auction you might be able to justify a 180mm TEC to your better half. I tried buying one a couple of years ago and there were none for sale globally - new or used - over a six month period. Just lots of people trying to track one down.

The TV Plossls are all superb for solar ha Neil! They are my go-to eyepieces for binoviewing the Sun. The XF zoom is in my view as good as the TV Plossls, which is pretty good for a complex eyepiece, and some orthos are right up there too, but you won’t find better eyepieces for sharp, contrast rich views of filaments and prominences than the TV Plossls. As you’ve discovered, they are also pretty good for night targets too, which is more than you can say for the XF zoom.

Excellent summary, and tbh it didn’t surprise me. The slight advantage offered by the DF in the report may become clearer on the planets at high powers, or with stringent star testing. But maybe not. The Tak should pull ahead with its slower focal ratio of F/7.4 v F/7, so that makes the cheaper scope’s performance even more impressive. Back in the 1990s, I worked as a journalist covering the motor industry - though quite why, I’m not sure, as I had no particular interest in cars. When I started, I remember doing a story on how far BMW and Mercedes were ahead of the mainstream pack - 3-series v Ford Sierra etc. By the time I stopped covering the industry, the gap had narrowed drastically. The BMW 3-Series still had rear wheel drive as its USP (bit like Tak with fluorite), but the new generation of Ford Mondeos etc were light years ahead of their predecessors, and very close to the Germans in quality and engineering. It’s fantastic that such a quality package is available today at Starfield prices. Yet I doubt that Takahashi is particularly concerned. They may be two and a half times the price of the Chinese brands, but it doesn’t seem to be hitting their sales.

I agree Peter. It’s just like a 3-6mm TV plossl with decent eye relief. Way too expensive new, and not quite at the level of the top planetaries, but the perfect high power tool for travel. I sold mine years ago, but I still remember the views of Mars and Saturn it produced from the Canaries.

Nice report - and very encouraging about the XO 2.5, Gerry. Hectic work schedule means I haven’t had a chance to really test the 5mm yet.

So you’d get rid of your Ethos John? At current prices they would be very expensive to reacquire if you missed them.

Nik - I will try and PM you about this this weekend - just super busy with work at the moment so don’t have time right now. I have some experience that’s relevant.

Excellent! - sounds like you’ve got a good one. The Quark will be stunning in your bigger refractor under the right conditions! It’s a real learning curve working out how to get the best out of these type of filters - but really good idea to start with the smaller scope. You should get more contrast on filaments with the 102mm with the slower focal ratio. One option for the future is to mask down the 102mm to 80mm or so - the slower the focal ratio, the better definition you’ll get on surface features.

Good spot! A medium C class is about half way up the classification rating for solar flares, so quite substantial. Don’t know what scope you’re using, but your Quark is perfect for high magnification flare watching when conditions are steady. I was incredibly fortunate last year to witness an X class flare on the limb which I could see moving in real time - without doubt the most amazing thing I’ve seen through a telescope. Hopefully there will be a few more this year.

No it doesn’t Gerry - Solar Spectrum is a US company - they are just marketed by Baader. Also the Baader Sundancer (Quark type filter) incorporates a Solar Spectrum etalon, but the etalons are all made in the States. Very nice quality on the whole - but PM me before you press any buy buttons.

The Baader ERFs are highly rated. Speaking of enthusiastic SV marketing, Baader’s blurb for its ERFs describes them as “hellishly diffficult” to make, with “the world’s most advanced coating machines, inspected on a Carl Zeiss optical bench. 1/10 wave”……. so should be as good as any ERFs.

That’s the question I was going to ask too. I found a couple of threads on CN in which people say they’ve used ERFs successfully as flats for DPAC - but they give no more detail.

I remember reading that energy rejection filters used for solar Ha might make good flats for DPAC testing. I have a 130mm Baader ERF that I use with a Sundancer/Solar Spectrum etalon - and I have a Ronchi eyepiece. Hmmm. Need to look into this further.

For an $18,000 triplet, I agree. But the vast majority of scopes sold as ‘apos’ have varying degrees of CA and SA. It’s why we can buy pretty good ED doublets for £300+. We can’t expect perfection with such competitive products. The only loser in the long term if we expect too much from cheaper scopes will be the consumer.

I read the Suiter book, and have to admit half of it flew over my head. However I understand the basics, and for people like me, the simple star test, done properly, is enough to establish whether a telescope is doing a good enough job to be happy with it. Only one of my refractors has ever shown a near perfect star test - the TSA120. The others have shown some false colour at high powers, and clearly contrasting rings either side of focus. Yet I’ve been happy with their performance under the stars. So, for most amateur needs, I agree DPAC results are not needed. But I’m interested in what they can teach me about optics - that’s the attraction rather than trying to establish whether my scopes are perfectly figured. The hi-fi analogy is a good one - I sometimes wonder whether hi-fi buffs are too wrapped up in sound quality to enjoy the music they are playing.

Three things: I second Jeremy’s comment earlier - I think Nicos has done a great job moderating the CN thread. Rather you than me mate…… I’ll follow your DPAC progress with interest Gerry. I don’t think you need a justification for investing in this gear besides an interest in optics. But whether I’d submit a telescope I am entirely happy with for testing is another matter. Perhaps it would show up my own shortcomings as an observer more than anything else…… With the quality of premium refractors so high and consistent these days, the CN thread has made me wonder the ramifications of amateurs having access to kit measuring how solar Ha etalons perform. Compared with expensive apos, the variation in etalons is dramatic - and yet a few solar experts are now able to test Ha filters with hydrogen spectrum tubes. That really could shake up the market.

On Gong, the prom is significantly taller than visible image - someone there needs to invest in a bigger blocking filter……. It’s obviously a real beauty. But no prospect of clear skies this afternoon sadly.