Just narrowing down from the last thread. The 4-4.5 inch APO category is quite crowded these days.
We have a large number of brands although I think a lot are the same Chinese scopes simply rebranded.
Astrotech, Sharpstar, Teleskop Services Photoline, Stellarvue Access, William Optics and perhaps others seem similar. APM even have rebranded Chinese scopes.
Then we have the higher end 4-4.5 inch scopes.
CFF, APM, Tak, Stellarvue, Televue. Perhaps others. CFF, Tak and APM being the upper band as far as I can see. Perhaps Skyrover?? Its new and hard to find a lot about them and sample images.
If you have a 4 -4.5 inch scope how would you rate the performance of yours?
These cheaper FPL53 air spaced triplets of any brand (all Kunming optics best I can tell), how do you find their performance? Would it be hard to see any gain in astrophotography using a more expensive scope? I suspect not but I could be wrong.
In the past my policy has been to get the highest end I can as I usually found that I was unsatisfied with a lower end scope, would sell it at a loss and end getting the high end scope eventually anyway.
I am not sure though that is still the case with some nice looking offerings notably from Teleskop Services who also sell flatteners and reducers, the scopes come with a rotating focuser, various adapters, a diagonal, a case, rings, finder scope holder. Tak does not give any of those just the scope and the addons cost another $1500 or more.
I have had a Tak FS102, Tak FSQ106N, Tak FSQ106EDX3, TEC110 F5.6 fluorite triplet in this category.
I liked the TEC the best but the focuser was too light for a large Proline. Shame I sold it to get another scope but it really needs a replacement focuser as its all too light weight. The lens though was divine and lovely colour in the images. FSQ106 is a great scope but limited in its image targets at 530mm. Also no good for visual really. The FSQ106N was better for colour but worse for vignetting (a weird black bar would go through bright stars near the edges of the images). Also its focuser seemed more sturdy plus the focus lock actually worked.
The FS102 is a fluorite doublet and not really APO. Nice scope, large and heavy though for a 4 inch scope.
I can say that Sky Rover is a rebrand, they're identical to the similar Teleskop Service ones. Optics are from Japan and the rest is from Kunming. My first Sky Rover had a quite substantial 4" focuser but my current one has a 2.5" that works well. It has a 3 element corrector installed inside the focuser so it cannot be replaced by a feather touch or a FLI Atlas but I have found it works well enough. Not sure how well it would go with a heavy Proline but it is reported with a 55mm imaging circle and I have found the correction to be pretty damn good. It may not have the correction of a FSQ130 but it is also 20-25% of the price.
Even some of the offerings that look very similar are at times a bit different. Some are FPL-53, some FPL-51 (both Canon-Optron in Japan) and others are FCD-100 (Hoya Japan) which is very similar to FPL-53.
The optics in a lot of these rebrands are routinely pretty good, the lemon slips through every so often but that happens with every company so it isn't just the Chinese ones that have issues.
For astrophotography though, especially with the larger Proline sensors, their failing is correction over a large chip. Most of them these days only offer up to 42-44mm correction which is pretty standard BUT the kicker is that one companies 42mm correction is another 36mm correction depending on how picky they are on spot sizes at the edge of the field. Take some of the old Tak Epsilons from the film days, they had a 44mm imaging circle but had near 20 micron spot sizes at the edge of field, my Sky Rover has less than half that.
Suavi has a CFF105 F/6 and that is probably what you should be looking at. It uses a Feathertouch focuser and they build flatteners with the correction required for what you're looking at.
Plenty of us use FSQ-106ED's for visual - in fact, it's one of the nicer visual scopes I have used, particularly since it is entirely flat in 2" or 1.25" EP's. Plus you can fit the extender to it too, making it f/8 and again lovely for visual AND imaging. Pkus you can also use the reducer with the ED line, making it VERY VERY fast.
Those black bars you saw in the FSQ-106N are NOT vignetting - it is a diffraction spike caused by the spacer foil in the objective (rectified in the FSQ-106ED series with a minor stopping ring). Many Taks have this - it even has it's own nick-name "lighthouse effect".
Thanks Colin. That is exactly the sort of response I was hoping for. A nice summary of the current state of play.
I was planning to use my Microline 16 (KAF16200 with 6 micron pixels and 6 electron read noise) with this new scope (needs a 34.5mm corrected circle). But it would be nice to be able to use the Proline which is more demanding (needs a 52mm corrected circle).
Yes it does seem that these cheaper triplets could be very good but the focusers may be a bit small (2.5 inch is getting small in my experience, APSc sensor only).
For the Proline that would require CFF, Tak, TMB/APM or AP. A 3 inch focuser would be the minimum.
I am leaning towards the CFF 105/F6 but its a 9 month waiting list. Not that I need one straight away. They also have a 135mm that is available sooner but of course more expensive.
Perhaps I should have another look at the Taks. But by the time you get the rings, finder scope, angle rotator, adapters with the exchange rates being low it sounds like not much change from $10,000 for the 120. That's a lot for a 120mm scope.
Since you asked. As I think I mentioned in the other thread. I have the TS Photoline 115mm f6,96 Triplet and cannot fault it as an imaging scope. The R&P focuser carries my cameras and filter wheel without any dramas. Focuser rotates as well, and has motor focus options frtom TS. The 3" Photoline reducer/corrector (0,79x) works well across the entire TS Photoline range, it reduces the 115mm to f5,53, and I also use it on my TS80. I have the TS Flattener as well but mostly i use the reducer corrector for the speed advantages. I will be bringing the 115mm to Astrofest if anyone wants to have a look. One of the reasons I purchased from Teleskop-Express was their pre-dispatch testing and collimation check, and the way they triple box these refractors, with the two internal shipping boxes suspended in a foam bead pack, with the scope itself riding in the same expanded EVA used in the optional hard case. I made my own hard case and simply moved the shipping foam to that. Photo attached.
Plenty of us use FSQ-106ED's for visual - in fact, it's one of the nicer visual scopes I have used, particularly since it is entirely flat in 2" or 1.25" EP's. Plus you can fit the extender to it too, making it f/8 and again lovely for visual AND imaging. Pkus you can also use the reducer with the ED line, making it VERY VERY fast.
Those black bars you saw in the FSQ-106N are NOT vignetting - it is a diffraction spike caused by the spacer foil in the objective (rectified in the FSQ-106ED series with a minor stopping ring). Many Taks have this - it even has it's own nick-name "lighthouse effect".
Thanks Lewis. Yes perhaps I was being quick to write it off visually. I only looked through mine a few times.
The vignetting I got that from Roland Christen who said that's what it was. Perhaps it wasn't right. I have seen that effect rarely on say a camera lens but not so much on a telescope. A weird one. So its those little pieces of aluminium that are separating the lenses and stick out a tad?
Yes, there are a number of Triplet clones in that size, under different brand names. I believe there are some differences in the objective material used, not all of them are using FPL-53, and where that is used you will of course get an unspecified lesser quality second and third element, and hence maybe this explains some of the price point variances. I have the TS Photoline 115mm f6,96 Triplet and cannot fault it as an imaging scope. It uses FPL-51 & Lanthanum glass (not a coating) element pairing, which Teleskop-Express claim equates to a FPL-53 single elelment (in a triplet) correction . The R&P focuser carries my cameras and filter wheel without any dramas. Focuser rotates as well, and has motor focus options frtom TS. The 3" Photoline reducer/corrector (0,79x) works well across the entire TS Photoline range, it reduces the 115mm to f5,53, and I also use it on my TS80. I have the TS Flattener as well but mostly i use the reducer corrector for the speed advantages. I will be bringing the 115 and the 80 to Astrofest if anyone wants to have a look. One of the reasons I purchased from Teleskop-Express was their pre-dispatch testing and collimation check, and the way they triple box these refractors, with the two internal shipping boxes suspended in a foam bead pack, with the scope itself riding in the same expanded EVA used in the optional hard case. I made my own hard case and simply moved the shipping foam to that. Photo attached.
Thanks Glen.
Its amazing value. Roland Christen predicted the Chinese scopes would eventually sap the high end market. I would really have to justify why I would pay 4X as much for a small gain.
I am really after around 105-115mm, around 630mm focal length and adjustable with reducers/flatteners and be able ideally to handle a Proline 16803 but if not then the Microline 16 which is APSh sized (26 x 22mm). It needs a 34.5mm corrected circle.
TS seem the people to use as they have the best range of scopes and accessories needed to make all this work. As you say the testing they do before they ship is reassuring given its a mass produced mostly Chinese product.
They have a few Q models that seem interesting that might even handle a 16803 sensor - well only the 86mm one. Starting to get too small though.
The M82 Riccardi reducer seems to have a slightly larger corrected circle. The 16803 needs 52mm and I'd say a 3 inch focuser minimum.
This use of Lanthanum is interesting. Roland Christen has said its not just having an FPL53 element but what it is mated with that makes it APO.
It seems very flexible and plenty of backfocus. A bit unclear what the corrected circle is though. I imagine its about 40mm.
The other one is the 100APOQ. 3 inch focuser, 49mm corrected circle (it may work with the Proline or just a small amount of cropping).
But if the focuser isn't great and the flattener is built in then that would be limiting.
The other option is just go for the CFF it has a 55mm corrected circle but its a 9 month lead time and twice the price.
Pentax 125mm SDP F4.9 with reducer may be nice if I could find one. I wonder if there is a Japanese 2nd hand telescope site? Its similar to a 130mm FSQ.
The Sharpstar 100Q - rebranded by TS and Stellarvue amongst others - is NOT very sharp. I contemplated it for a while, but it is quite soft, and noticeable blue halation. I have spoken at length to the Sharpstar guys, and they cannot and will not guarantee a good one, and I have read MANY reports - including by the Hong Kong dealer of them - about dirty optics etc. The standard focuser on them is iffy - that is why SV replaces them with FT and jacks the price WAY up accordingly.
The Vixen VSD100 also is not as sharp as Tak, and shows again halation. I had the older Pentax version, and I can NOT recommend it, especially for modern CCD's. Seems fine for film, not so much digital.
The Sharpstar 100Q - rebranded by TS and Stellarvue amongst others - is NOT very sharp. I contemplated it for a while, but it is quite soft, and noticeable blue halation. I have spoken at length to the Sharpstar guys, and they cannot and will not guarantee a good one, and I have read MANY reports - including by the Hong Kong dealer of them - about dirty optics etc. The standard focuser on them is iffy - that is why SV replaces them with FT and jacks the price WAY up accordingly.
The Vixen VSD100 also is not as sharp as Tak, and shows again halation. I had the older Pentax version, and I can NOT recommend it, especially for modern CCD's. Seems fine for film, not so much digital.
Thanks Lewis. You are a font of information!
Very handy, thank you.
So the TS 107 F6.96 with the variable tube length adapters seems the way to go or stump up and wait for the CFF or go for another FSQ.
I love FSQs but want a little bit longer focal length as the 530mm native focal length is a tad short. 630mm may be more useful to me to get the look I am after in the images and a focal length I don't have covered at the moment.
I don't know much about the TS 107mm. The 3" Photoline Reducer/Corrector can give you a 45mm illuminated field. If you want your stated focal length, and speed, the Imaging Star 130mm f5 would give you 650mm focal length, but a slightly smaller illuminated field (42mm) and it a 6 element with inbuilt flattened.
It will be interesting to see what effect the new US 25% tariff has on Chinese manufactured scopes. The US HTS code for optical telescopes was 8% up till now. Optical equipment was certainly on the new tariff list when i had a look. If Kunming, and other Chinese manufacturers, get hit with a 25% tariff what does that do to the global market? The TAK people will be delighted, as will the US makers, I am sure.
It is identical to the Sky Rover 130mm I'm currently using. TS have been through different focuser designs for their version but have ended up with the same one I'm using now. It used to have an odd M65 or M63 connection but they've since decided to standardise it to the M68.
If you want a telescope that you can use visually, this isn't one for you. It has a back focus of 74.5mm from the M68 thread on the draw tube so unless you get a special very short 1.25" diagonal you'll never achieve focus with an eye piece without laying on the ground
Due to the way that it is designed, it is technically a F/5 but with the interaction between rear flattener and correct back focus it is a photographic F/5.2 at 675mm focal length. It is a nice astrograph.
I may just add that I really liked my TS ED 102mm f/7 Photoline telescope - it had a solid 3" focuser and a nice reducer. It came in a double cardboard box with some styrofoam cut-out pieces that well protected the cargo. I did upgrade the focuser though to a 2.5" Moonlite with a rotator. The only reason I sold it, and after long research bought 105mm CFF, was a bit imperfect colour correction of my TS doublet.
The quality of CFF is a few notches higher thany my previously owned TS - starting from impeccable second to none packaging, machined solid tube that won't flex, machined baffles, solid 3.2" FTF and beautiful optics including a substantial dedicated CFF corrector.
Having said that, from my experience with a TS doublet, I am confident that their triplets are also very good and capable for capturing great data. But I'm also glad I splashed a bit more on an instrument that was made with a great attention to detail.
I may just add that I really liked my TS ED 102mm f/7 Photoline telescope - it had a solid 3" focuser and a nice reducer. It came in a double cardboard box with some styrofoam cut-out pieces that well protected the cargo. I did upgrade the focuser though to a 2.5" Moonlite with a rotator. The only reason I sold it, and after long research bought 105mm CFF, was a bit imperfect colour correction of my TS doublet.
The quality of CFF is a few notches higher thany my previously owned TS - starting from impeccable second to none packaging, machined solid tube that won't flex, machined baffles, solid 3.2" FTF and beautiful optics including a substantial dedicated CFF corrector.
Having said that, from my experience with a TS doublet, I am confident that their triplets are also very good and capable for capturing great data. But I'm also glad I splashed a bit more on an instrument that was made with a great attention to detail.
The CFF sounds like the scope to have at the moment. They have a great range of sizes and options. They seem to be getting more popular.
I may just add that I really liked my TS ED 102mm f/7 Photoline telescope - it had a solid 3" focuser and a nice reducer. It came in a double cardboard box with some styrofoam cut-out pieces that well protected the cargo. I did upgrade the focuser though to a 2.5" Moonlite with a rotator. The only reason I sold it, and after long research bought 105mm CFF, was a bit imperfect colour correction of my TS doublet.
The quality of CFF is a few notches higher thany my previously owned TS - starting from impeccable second to none packaging, machined solid tube that won't flex, machined baffles, solid 3.2" FTF and beautiful optics including a substantial dedicated CFF corrector.
Having said that, from my experience with a TS doublet, I am confident that their triplets are also very good and capable for capturing great data. But I'm also glad I splashed a bit more on an instrument that was made with a great attention to detail.
Quote:
Originally Posted by Atmos
It is identical to the Sky Rover 130mm I'm currently using. TS have been through different focuser designs for their version but have ended up with the same one I'm using now. It used to have an odd M65 or M63 connection but they've since decided to standardise it to the M68.
If you want a telescope that you can use visually, this isn't one for you. It has a back focus of 74.5mm from the M68 thread on the draw tube so unless you get a special very short 1.25" diagonal you'll never achieve focus with an eye piece without laying on the ground
Due to the way that it is designed, it is technically a F/5 but with the interaction between rear flattener and correct back focus it is a photographic F/5.2 at 675mm focal length. It is a nice astrograph.
Thanks Colin. 78mm is probably just enough for my imaging train with 6mm to spare. So that is good.
Greg, get the FSQ-130ED and show us some images from it. I have been waiting patiently for someone to get one and show us what it is capable of.
H
Hehe. Trouble is it costs around $21K landed. A lot for a 130mm scope.
There are a few images around. I have seen some. They were nice but not outstanding. As I recall though they were with a modded DSLR which seems a mismatch.
