Andrew_B

Modern doublets can be so good that for visual use you might not see any difference compared to a triplet. They also cool down faster, weigh less, and tend to be a bit easier to mount and balance due to being less lens-heavy which also makes them a better fit for a grab-and-go scope.

If your budget can stretch to a 4" apo then I think you'd really enjoy it and it would make a great companion to your dob.

Thanks to Japanese efficiency, my 6mm Fujiyama ortho which had only left the factory on the 23rd and was dispatched from Kyoto on the 24th, arrived just after lunch on Monday and by some sort of miracle there was a long enough spell of clear skies for it to see first light a few hours ago.

I tried it with the following configurations of my little Tak:

FS-60Q - 60mm aperture, 600mm focal length (f10)

FC-76DCU - 76mm aperture, 570mm focal length (f7.5)

FC-76Q - 76mm aperture, 954mm focal length (f12.6)

I was able to view Jupiter and Saturn with the first two and the Moon with the latter using the 6mm ortho to give magnifications of 100x, 95x, and 159x respectively. Seeing was okay to begin with but worsened significantly towards midnight and I had clouds and reducing transparency to contend with as the night wore on. Despite this the little eyepiece delivered impressively sharp views of all targets with plenty of detail visible in Jupiter's atmosphere and the moons rendered more clearly as tiny disks than I've seen with any other eyepiece so far (BST 8mm, Nirvana 4mm, Hyperion Mk IV Zoom with and without 2.25x Barlow). Saturn was very low but some banding was visible and the shadow of the planet on the rings was surprisingly crisp in moments of better seeing. Unfortunately the Cassini Division was much harder to spot and far from clear when it was visible, but this was obviously the result of the planet's position in the sky rather than any shortcomings in the eyepiece.

It was too windy to bother with the longer FC-76Q outside but I set it up looking out of a bedroom window to observe the rising Moon around midnight. Seeing had deteriorated significantly and being indoors won't have helped, with the view of the Moon being obviously affected by the turbulent atmosphere even at just 27x magnification using a 36mm Plössl. Upping the mag to 159x using the 6mm ortho I was pleasantly surprised by the brief but absolutely razor sharp views it gave me during moments of better seeing that suggested both scope and eyepiece had plenty more to give. Unfortunately the appearance of fairly thick haze meant that this wasn't going to be the night to explore those limits.

To summarise if you don't mind the relatively narrow FOV (not an issue for planetary observing IMHO) and the contact lens-like eye relief then the little Fujiyama will deliver remarkable views in a tiny and lightweight package that's the perfect match for a small refractor or other lightweight grab-and-go scope. The price is a step up from budget eyepieces but I think it represents very good value for money given how well it performs, and I'm keen to try out some of their longer focal length orthos when funds permit.

10 hours ago, jetstream said:

You realize the "big boys" like avani and kokathaman use C14's

They are both excellent resources BTW.

I thought the big boys had moved on to 16" and upwards RCs, CDKs, and weird astrographs with ultra-fast focal ratios and unpronounceable names! SCTs seem to be positively old hat at the high end of the "amateur" market.

Some of the imaging gear being used by hobbyists these days wouldn't be out of place in many smaller professional observatories.

To answer Fedele's question, I'm not sure the jump from 180mm to 210mm would be enough to justify the effort and expense. You're talking about an improvement in resolving power of less than 17% which I doubt you'd notice, and an increase in light grasp of 36% which again isn't that much.

7 hours ago, Mark99 said:

Thanks so much guys, looks like AD then.

I can't bring the 'scope to focus straight through. I do need to check the diagonal as that is a new (secondhand) acquisition.

KP, can you give me some pointers on the type of lenses I should be looking for?

I have the same diagonal (assuming it's the 1.25" version) and it's got a relatively long optical path compared to the prism I'm currently using with my new scope. I haven't been able to find the figure for the optical length of that particular model, but a similar looking one from Astro-Tech apparently has a 94mm path length.

What that means is that without the diagonal in place and with the focuser at the same position, you would need to add 94mm of extension to allow your existing eyepieces to reach focus.

17 hours ago, Sunshine said:

Well, to be honest I don't mind the typical spikes I have seen in previous scopes (on stars) it is the 6 spikes on Jupiter which were mentioned in one review that had me wondering, I really never knew spikes were possible on a planet. 

Maybe it is a mewlon phenomenon only?? then again, I am just contemplating and judging without having used the scope, I just can't imagine Jupiter with 4 spikes, let alone 6!.

The thing about the Mewlon 180 design is that although you get 6 spikes instead of the usual 4, they'll be fainter than you'd see from a conventional spider.

I'm surprised nobody's offered an unobstructed Cassegrain or three-mirror design given their advantages and appeal to the discerning amateur but perhaps they're too hard to design and make for anything other than very high-end gear.

On 25/09/2021 at 10:23, Stardaze said:

Really interesting thread.  I’ve really enjoyed watching the two gas giants across these last 6 weeks and am very pleased with my XW 5mm & 7mm, the latter has really exceeded all expectation I had. Was toying with the idea of a 6mm Fujiyama but certainly will keep my eye out for a 3.7mm HR too. I think a TOE wouldn’t see enough use in my dob for the outlay. 

I've ordered a 6mm Fujiyama which should arrive this week so no doubt the weather will be terrible!

I found that for high magnification planetary observing I don't particularly like wide fields or lots of eye relief so it'll be interesting to see how I get along with this and the 6mm focal length should be a good fit for my gear.

On 25/09/2021 at 17:21, John said:

I had the 4mm Nirvana for a while and it turned out to be an excellent high power eyepiece

 

I've got that and it works well. The Double Double was a surprisingly easy split with the Nirvana in my little FS-60CB at 89x.

The only negative point is that I sometimes find it harder to get my eye in the right position to get the best sharpness than I do with my 8mm BST Starguider. I don't know whether that difference is a function of the focal length difference or whether it has more to do with the fundamental design of each eyepiece.

How are these chairs on softer surfaces like a lawn? Are they usable and stable or do they tend to dig in and topple over?

1 hour ago, Deadlake said:

I suspect Japan has one foundry for the glass, the furnaces have Palladium walls to produce FPL type glass. These foundries use to exist in the US until the bean counter's sold them off as the furnace was worth more than the business it supported. The only other foundries will be in Russia and China.

I remember reading about that. Companies like Kodak and Bausch and Lomb had these glass furnaces with solid palladium or platinum linings, crucibles, and stirrers and when catalytic converters started being added to every car the demand for these precious metals went through the roof and the price rose accordingly so they scrapped the furnaced and sold the metal. Staggeringly short sighted.

Presumably all the glass for US-made high end optics is sourced from overseas then now? The optics divisions of these companies still exist, just under different names and often catering to defence clients. Leica Canada is now Raytheon ELCAN and Kodak divested that part of their business as Itek which is now part of L3Harris - they're the folks who make the optics for spy satellites and have done since the 60s.

4 minutes ago, John said:

Do they make the glass as well ?. I believe they do with Fluorite but how about the glasses used in the TSA and TOA refractors ?

 

Good question. Optron is one of a handful of fluorite manufacturers - the main use for the stuff is industrial optics and in photolithography machines in particular which is why it's available as extremely high quality blanks far larger than is available with comparable optical glasses. Blanks of sufficient quality for telescope optics are made up to 440mm - can you imagine what one of them would cost 😲

I think the TSA uses FPL-53 and the TOA models definitely do so presumably Canon would be buying the blanks for those from Ohara. I wouldn't think they'd make the mating glass in-house either so that probably comes from Ohara or Schott, but I could be wrong because in one of Canon's videos about their lens making they appear to be producing glass from the raw materials.

2 hours ago, ollypenrice said:

Life's too short to read all of a thread like that but by the end of page one I hadn't found a leaking TEC...

Olly

I've read of it happening with the occasional older Astro-Physics scope but it seems to be one of those very rare issues that if it does occur then you're going to hear about it.

Bacterial growth and mould on lenses of any type is more common but often that's a result of people putting scopes and camera gear in cold and damp attics or leaving thing for long periods in sheds and garages. My stuff stays in the front of the house where it's warmest and driest.

3 hours ago, John said:

I was using 600x on tight double stars and to spot Triton last night with my LZOS 130. 240x seemed the best for Jupiter and 300x did well on Saturn. Your LZOS (and @Stu's) are very similar optical quality I think. If you get the seeing, pump up the power ! 

Hope you get some good sessions in with the scope soon

A question for TSA 120 owners if I may: We know that Canon Optron make the objectives for the Tak Fluorite doublets. Do Tak make their triplets (such as the TSA) themselves or is a third party optical house involved for those ?

Edit: Just found the answer from Roger Vine's review of the TSA 102: "The TSA-102’s lens is an air-spaced triplet made in Japan by Canon/Optron"

 

 

 

From what I've read Canon Optron have been Takahasi's supplier of lenses since at least the late 70s and that it was they who approached Tak about making a Fraunhofer fluorite scope after they'd developed a method for hard coating the stuff. Apparently when they were testing the prototype lens they went as far as scrubbing the surface with a wire brush and it did nothing! There was a suggestion of using this in the marketing to show how durable the coatings were but it was quickly shot down as they didn't want to encourage people to do stupid stuff like that.

Lens design is done in-house, as is manufacture of lens cells and the grinding and polishing of mirrors.

1 hour ago, dweller25 said:

I would go for an air spaced scope as oil gets messy when it leaks 🥴

Also I wouldn't want to have to mess around changing the oil and the filter every 15,000 light years!

3 hours ago, ollypenrice said:

It is primarily connected for visual, yes. Regarding its imaging prowess, there's an interesting debate. I've seen it dismissed by one CN poster as 'a glorified achromat,' an opinion I find incomprehensible.  What many imagers have found is that the blue correction is greatly improved by the TEC field flattener, though the official line from TEC is that this is not true. My own experiments with and without the flattener clearly suggest that it is true. A slight tendency to bloat on hot stars disappeared with the flattener, which is a prodigious bit of kit giving a vast, well illuminated field larger than any current amateur cameras can exploit. I love it as an imaging instrument. Some samples...

https://www.astrobin.com/full/335042/0/

https://www.astrobin.com/full/380941/0/

https://www.astrobin.com/full/419975/0/

We have two of them here with no discernible difference in performance.

Olly

 

Those are some great images and I can well believe that the flattener helps with blue correction because I'm pretty sure I've seen that mentioned as a property of some other flatteners and reducers.

Calling it a glorified achromat is pretty ridiculous. I've never read anything to suggest it's less than a superb visual apo or that it's actually bad for imaging, just that other exceptional scopes might be better.

On 22/09/2021 at 09:57, F15Rules said:

One final point..someone mentioned "squinting" while cyclops viewing..I do agree that is a pain, but I easily solved the problem by buying a black eye patch..I have both eyes open, so no squinting, but simply observe via a single eye. Simples!!😊

Dave

I think I need to try that because I often find myself squinting and it quickly gets uncomfortable.

Just the one question, is the wooden leg and parrot included or do you have to buy them separately? 😄

8 hours ago, ollypenrice said:

Taking a step backwards in time, we might care to remember that the original TEC140 was, if this isn't an oxymoron, a budget 'premium apo.' It was non-fluorite and sub 150mm and oil-spaced, all of which put it below the eye-watering prices of the premium 6 inch opposition, yet it ran them close. Close enough, in fact, for this aspect of its history to have been forgotten since it tends to be regarded, now, as one of the full-on premium contenders. (I'm talking about the pre-fluorite versions.) Also helping this creeping advance up the food chain was the TEC reputation for quality control and accessibility, neither of which are Takahashi strong points (though I think it's mostly the FSQs which seem to defeat Tak's best efforts to send them out in consistently good fettle.)

I've just looked up the price of the current Tak 150.  Had I gone for that rather than my second hand TEC 140 I would be about 11,000 euros worse off. Eleven thousand euros!!!  If someone offered me a straight swap, my TEC for a new Tak 150, I'd decline because I wouldn't risk it.

Olly

 

I think the issue with the TOA was in a small number of the very early models and the issue was fixed quite quickly. I've not read of anyone having problems since then.

The TEC does seem to be one of the few high end apos that anyone in the UK carries in stock although I don't know how often they appear on the secondhand market outside the States. Am I right in thinking it's corrected for visual use in the main? I seem to remember reading and that the alternatives from CFF or Tak were a noticeably better choice if you were imaging.

Highburymark's suggestion of removing the section ahead of the focuser is your best option but part of the problem is that your SkyWatcher mirror diagonal will have a much longer optical path than your excellent little Tak prism. I had a similar problem trying to use my StellaMira mirror diagonal with my FS-60CB / FC-76DCU and I ended up using the entry level Baader T-2 prism. I attached a nosepiece which has a 1.25" thread but I could probably have threaded it onto the scope directly using an appropriate adaptor.

6 hours ago, doublevodka said:

Some excellent points there and it's good to see a manufacturer pushing the boundaries of automation, even if it is eye wateringly expensive

The thing that frustrates me about astro kit is it's generally way behind the current technology

As far as I'm aware (and welcome to be wrong) no one has developed a fully automatic EQ mount and the question is why? Motors are cheap, camera sensors can also be cheap so why can't we buy a mount that you set down and it automatically aligns the RA axis to the NCP and then the scope to the sky? Surely it can't be that hard?

The closest I've seen so far is the Meade Lightswitch - https://www.meadeuk.com/Meade-LightSwitch-LS-ACF-telescopes.html but then it's AltAz and not everyone wants an SCT

Yes you can add on cameras and use software etc, but there's still an amount of manual work involved that I suspect the big manufacturers could easily solve

Ok everyone might not like Vaonis products or costs, but personally I think it's nice to see a bit of innovation going on 👍

I'm with @tooth_dr on this one, it's gone on the euromillions list 😉

Very good point about how primitive mounts are.

Thinking about an app like Star Walk, it can show me a map of what's in the sky above me using the various sensors in my smartphone. It might not be pinpoint accuracy but it should do a good enough job of knowing the location of the celestial pole that the same basic technology could be applied to a mount to let it auto-align. I'm sure there are other methods that would work and the hardware to do it wouldn't be expensive in the context of a decent EQ mount.

Like you say, the current systems all require much more human intervention than is really necessary and take time to set up that could be better used doing actual imaging, especially during the summer months when nights are so short to begin with. Even though I wouldn't buy this product and it wouldn't appeal to many on here the ideas behind it are solid and could be applied to other equipment without necessarily creating such a tightly integrated and rather limited system.

4 hours ago, iantaylor2uk said:

Any takers for this?

https://www.space.com/vaonis-hyperia-telescope

To be honest I would think a 10micron mount and a 120 Tak would be much better (and considerably cheaper)

 

 

 

 

 

 

A 10 Micron mount and a Tak 120 would still require you to research and buy all the other stuff then spend what could be a long time getting it set up. That effort is only free if your time is worth nothing and much as I enjoy astrophotography, the truth is there's an awful lot of messing around in the hobby that gets in the way of actually taking photos.

There's a reason the traditional camera market is almost dead when I can take a photo with my smartphone that's better than any compact camera was in the days of film, then quickly edit it on the phone and save / upload / share it instantly. Compare that to using a standard digital camera then having to wait until I get home to save images from the SD card onto my computer then load them into editing software, etc, and there's no comparison in terms of ease of use, time saved, and convenience.

A lot of astrophotography is way more complex than it needs to be and the best thing the equipment can do is to get out of the way of the user.

The same eyepieces seem to be sold under the Maxvision brand as well but for whatever reason there don't seem to be any 8.8mm ones available. Must be a popular focal length.

If you're finding it a real chore to set up and break down and it's getting in the way of your observing then it's definitely worth changing for something more convenient that you're more likely to use on a regular basis.

There are a lot of smaller options you could get instead but the best choice would depend on what you like to observe and how big a scope setup you would prefer to have. If you like the Moon and planets then something like a Maksutov might suit you perfectly although it's not the best choice if you prefer wide field views of DSOs.

12 hours ago, Gondalf said:

Hi, thanks again to everyone for the suggestions.
I tried today to check if the scope is collimated and it appear to be so, so that's a good news.

How long would you say you need for it to cooldown properly? (Here in Portugal we're at about 16º/17º at night, don't know if it matters).

 

My gf wants to gift me something to help this new hobby and I was thinking on a set of lenses, from reviews I found that Svbony makes good ones, but I see two very similar sets:

https://www.amazon.es/-/pt/gp/product/B07BFWFVNP/ref=ox_sc_act_title_1?smid=A3ICDZYF91YIY1&th=1

https://www.amazon.es/-/pt/dp/B07B8KVX7G/ref=cm_cr_arp_d_product_top?ie=UTF8

Is there much difference between these two?

 

I'm also getting a filter as suggested above, and stumbled upon something called a barlow lens, which I read is to magnify my view X times. Is it worth it for my setup?

 

Thanks again for all the help so far!

I couldn't tell you about cool down time specifically because I don't have a Dobsonian, but it shouldn't be very long with those outside temperatures. What you can try is have a look through it as soon as you take it out then have another look every 5 or 10 minutes to see how much the view improves and how long it takes until the image quality stays the same.

If you can put your scope out for an hour before you want to observe then it should definitely be ready and performing well when you start using it.

I've not tried those eyepieces but I do have a Svbony Plössl which I've been impressed by. It gives a lovely bright image, it's sharp across most of the field and very good value for money. I think they're basically the same as the Celestron Omni Plössls but for a much lower price.

Another factor could be whether the scope had cooled down properly. If it went from being indoors and warm to being out in relatively cold night air then it would need time to reach ambient temperature and until that happens you get air currents inside it which disturb the light and reduce image quality significantly. Bigger scopes take longer to cool and tend to be more sensitive to temperature issues from what I understand, especially compared to a small refractor like your Celestron which will be ready to use almost immediately.

19 hours ago, johninderby said:

The FT crayford is good but the R&P focusers take it to a new level. Smoother and more precise and handle more weight but start at 2.5”.

https://starlightinstruments.com/store/index.php?route=product/category&path=37_54

Had a 3” R&P on an FLT98 and was an incredible focuser. Best I’ve ever used but silly money to buy now. 🙀

 

Could be that they see a Crayford as being good enough for the smaller and lighter weight scopes that would have a 2" focuser attached.

I've got one ordered to put together an FC-76DCU and I wouldn't want to be hanging enormous cameras off it or want a focuser that was very heavy when the scope itself is so light.

Prices are getting a bit silly though, and even the low end models are an expensive upgrade.

48 minutes ago, iwols said:

thanks dave  went in car park and went left ,so the gate is on the opposite side of the road,what duration/quantity were your images and it really was a clear night first time ive been here,do you think the skywatcher adventurer would be any benefit?

The Star Adventurer is great for Milky Way photography. It's relatively easy to set up and with a wide angle lens you don't have to worry so much about small tracking or alignment errors. You can then bump up the exposure time for each image and take more in total to produce your final stack.

Here's a shot I did with a Samyang 12mm consisting of 100 30s exposures. It was taken in the North Wales countryside so probably Bortle 3 but it was in August so the sky wasn't getting properly dark anyway. It's not amazing because I'm just a beginner but it gives an idea of what that combo can do. The blur at the bottom of the image is a foreground tree.