SVBony - New OTA - My Gawd they've gone and done it again.

[chris_g]

SVBony is releasing a triplet OTA 122mm F/7 for a ridiculously low MSRP when compared to other triplets. If interested, check it out.

https://www.svbony.com/sv550-apo-refractor-122mm/

Features：
1. The SV550 APO Triplet refractor with 122mm aperture and f/7 focal ratio, a great travel telescope for observation and astrophotography
2. Fully multi-coated triplet apochromatic optics using an ED center element
3. 2.5" dual-speed rack-and-pinion focuser 10:1 ratio fine focusing with M63x1 female thread for adaptions
4. Retractable lens shade/dew shield-the APO even fits into the hand luggage
5. CNC multi-function Dual hinged split tube rings with a 300mm versatile V-style dovetail, support mounting of various accessories
6. Finder shoe on the focuser is included
7. Multipurpose shock-absorbing telescope protective bagrunning AstroDMx Capture

[Bigzmey]

Attractive package indeed. How do you like your SV405CC?

[messier 111]

thx

[chris_g]

Attractive package indeed. How do you like your SV405CC?

Glad you asked, it failed within the first six weeks I had it. I worked with SVBony support through Amazon Seller Central and they replaced it with a brand-new package and I got to keep the accessories from the new one when I returned the old one. They also paid for shipping back to China. I like it, it's given me the exposure to dedicated astrophotography cameras at a price that isn't ridiculous. ZWO's version is $999 and SVBony's is $799, the only difference is the 405CC doesn't have a USB 2 hub on it. You can usually get it for cheaper than that through Amazon. I got mine for $740. The quality of the images is the same between the two on Astrobin. I also use one of their toy telescopes as a guide scope, the SV503 70/400. It can be difficult sometimes because of nature of the build being plastic but once it's locked in, the optics performs just as well as my more expensive and HEAVIER guide scopes. They also introduced a mono cooled camera for $899 based on the IMX533 chip, ZWO's version is $999. Again the only difference would appear to be no USB 2 hub. Sorry ZWO, two usb 2 Ports aren't worth $100 to $200.

I was hoping for a refractor at a longer focal length, something in the range of 1000, I'm patient and hoping that they have one when I'm ready to add another OTA to the collection!

Clear Skies,
Chris

[Lady Fraktor]

These are the most common refractors in the (approximate) 1000 mm range. At 1000mm most refractors are usually OK4, FPL or fluorite which means expensive. With the extended focal length they can be 'essentially perfect' in colour correction.
https://www.teleskop-express.de/shop/pr ... cuser.html
https://www.teleskop-express.de/shop/pr ... uszug.html
https://www.firstlightoptics.com/telesc ... cuser.html

After reading the SVBony marketing, to me it is just SVBony leading the charge to the bottom again...
Nothing personal Chris, just my opinion about SVBony. My comments are only about the telescopes and nothing to do with their other products either.

Features：
1. The SV550 APO Triplet refractor with 122mm aperture and f/7 focal ratio, a great travel telescope for observation and astrophotography
Pretty standard so far other than a uncommon clear aperture.
2. Fully multi-coated triplet apochromatic optics using an ED center element
Meaningless without knowing the mating elements or grade of glass. Pure marketting.
3. 2.5" dual-speed rack-and-pinion focuser 10:1 ratio fine focusing with M63x1 female thread for adaptions
Nice focuser
4. Retractable lens shade/dew shield-the APO even fits into the hand luggage
15 lb and 34.5" is hand luggage? Not on any flights I have taken. Do not expect it to survive in the hold in a suitcase either.
5. CNC multi-function Dual hinged split tube rings with a 300mm versatile V-style dovetail, support mounting of various accessories
Fairly standard rings, 12" extruded vixen dovetail will vibrate with 15lb scope + AP stuff on it, better a solid one or Losmandy plate.
6. Finder shoe on the focuser is included
Normal
7. Multipurpose shock-absorbing telescope protective bagrunning AstroDMx Capture
What is this even supposed to mean??

On the marketing page they show this a few times: ( FPL-51 triplet>FPL-53 doublet) which is just wrong.
At a focal ratio of f/7 the 53 doublet will still be slightly better than 51 triplet in colour correction if the elements are similar quality.

[chris_g]

These are the most common refractors in the (approximate) 1000 mm range. At 1000mm most refractors are usually OK4, FPL or fluorite which means expensive. With the extended focal length they can be 'essentially perfect' in colour correction.

fter reading the SVBony marketing, to me it is just SVBony leading the charge to the bottom again...
Nothing personal Chris, just my opinion about SVBony. My comments are only about the telescopes and nothing to do with their other products either.

I will defer to your opinion, I know nothing of glass and lenses, no offense was taken. You do mention though that one of the more expensive lenses is FPL, the specs for the SVBony say ED Glass FPL 51. You also mention 1000mm focal length, I want one at least capable of that range which knocked SV Bony's out. This one is 854mm native, with one ED lens, would that be the cost reduction in tune of hundreds, I did see the specs on the glass for the two you showed were FPL53 instead of FPL51 and two ED lense instead of one?

I did paste the marketing instead of the specs page

Thank you, time for some new aditonal internet search...


Specifications

Brand​ SVBONY​
Model SV550
Aperture 122mm
Focal Length 854mm
Focal Ratio f/7
ED Glass​ FPL51​
Telescope Type Refractor
Resolution 1.15 arc seconds
Coatings Fully Multi-coated​
Tube Material Aluminum
Focuser 2.5" rack-and-pinion, dual speed (1/10)
Tube​ Travel 87mm
Visual Limiting Magnitude 12.3
Lens Design Apochromatic​
Dovetail Plate Length 300mm
Highest Useful Magnification 244x
Additional Thread M63x1 female thread for adaptions​​
Dew Shield Type Retractable
Net Weight​ 6440g/14.18lb
Gross Weight​ 10000g
Thank you,
Chris

[chris_g]

Quick search answered questions, thank you. Know what you want! Knowledge is power..

FPL 51, 52 and 53 and fluorite. 53 is better at CA than 51 but is more "fragile", 51 can be perfect at longer focal lengths, a whole host of quality on the mating elements will drive things up...fluorite, I don't see the benefit to justify the cost.

As always. @Lady Fraktor, thank you

Clear Skies,
Chris

[Lady Fraktor]

FPL 51, 52 and 53 and fluorite. 53 is better at CA than 51 but is more "fragile", 51 can be perfect at longer focal lengths, a whole host of quality on the mating elements will drive things up...fluorite, I don't see the benefit to justify the cost.

Fluorite has many benefits but like any other glass it may not be required for what you want your telescope to do.
O'Hara makes FPL-51,53 and 55. FK-52 was made by Schott (no longer produced)
All ED elements are soft, 51 and 55 are harder and easier to work.

[Lady Fraktor]

Hello Chris, this is going to wander a bit as it is 05:30 in the morning and I am having breakfast

I will not touch on fluorite as it is a whole topic on itself.
OK-4, FPL-51,53,55, FCD-1, FCD-100, FK-61 are the most common extra low dispersion glasses used in our optics.
These of themselves do nothing to make a good refractor without a proper mating element(s).

All of these are ED glass, the SD designation is strictly marketing to separate you from your $$.

The one we hear/ read about the most is Lanthanum BUT Lanthanum can be a glass or it can be added to a base glass melt or it can just be doped onto the glass like a coating. Each method has different corrective properties.
There are other backing glasses, many of which are more expensive than the ED glass itself. A good example is Schott glass N-ZK7 which is typically 3x the price of FPL-53 (meaningless but I will give context later)
So in reality we have to put a lot of trust into the manufacturers or spend a bit of time learning some of the specifics to see if it will meet our expectations.

Grade 1-4(Perfect-Good), Scratch Dig 1-4(amount of internal bubbles-scratches)
Optical extra low dispersion glass usually comes in at least 4 different grades and in 4 different scratch/ dig ratios.
The best grade- s/d ratio is usually for military, high end scientific instruments and small amounts to boutique optic houses. Grade 3-4 is normally for consumer and mass produced consumer optics and they may have a s/d ratio between 2-4 depending on usage.
Grade 2 is common for premium/ boutique optical houses (Astro Physics, TEC, Agema, AOM, CFF, Takahashi etc.)
and s/d ratio of 1-2.
We would all like to think that we have the best glass available in our refractors but seldom is it the case.

One issue I see happening a lot due to marketing, is that many people equate the term apochromatic with the quality of the product when it only refers to the colour correction. Three elements also do not make a apochromat!

Cost of FPL glass
Glass manufacturers base their cost on their cheapest glass which for O’Hara is S-BSL7 (Schott BK7)
If S-BSL7 cost is 1, then FPL-51 is 11x and FPL-53 is 18x more. So the Schott N-ZK7 is 54x the cost!!
Now the thing to understand is this is the price per kg with Grade 4 glass. As the grade and scratch/ dig ratio improve the price increases exponentially with aperture as well.
One example is the AOM 130/ 1200 FPL-51 doublet using grade 1 glass, the cost difference for the 160/ 1600 FPL-51 lens using grade 1 was 350%!!!

ED glass main function is to allow making a short focal length telescope. Used in longer focal lengths it eases the designers choices for mating elements and makes negating SA and other aberrations easier.
Telescopes can be made apochromatic using only standard glasses, even the ‘apo’ refractor that got Astro-Physics on the market had no ED glass in it.

If you have any questions let me know, I understand this wanders a bit but the morning caffeine has not kicked in yet.

So the eventual question is, how do you think SVBony can offer that size telescope at that price?

[chris_g]

So the eventual question is, how do you think SVBony can offer that size telescope at that price?

Thank you, very much! I followed fully with my first cup of coffee, now processing with my second cup!

A little bit more about the OTA, it's supposed to be an upgrade of their ED80, the coatings listed for that are SMC. They say nothing of the mating element and from what I've learned that one is what really decides the quality oi the scope.

So, most other triplets have two ED elements instead of one, most other triplets in the same category are made with FPL 53 instead of FPL 51. Don't know enough about what coatings SVBony uses, (may be SMC) and don't know anything about the mating element. Based on this knowledge, what we have here is a bargain basement triplet that should perform at least as well as my EveoStar Doublet, (uses the same glass).

So, to answer the question, no ma'am, they cannot.

So, my final question is a scope worth $600 plus more for those two specs? No, buy a Skywatcher EvoStar 100ED, and save $600 plus which does actually fall into the focal length I'm wanting, though I am not looking to buy at this time.

I like the company for their support and cameras, I like their toy OTAs for use as a guide scope. The quality of the coatings on the toy scope are good. If I were just getting into astrophotography and these scopes were available, I would probably have bought one then. Marketing aside, decent entry level scopes at a decent price. Know what you're buying...

Thank you again,
Clear Skies, Chris

[Lady Fraktor]

So the eventual question is, how do you think SVBony can offer that size telescope at that price?

Thank you, very much! I followed fully with my first cup of coffee, now processing with my second cup!
Coffee is a great way to start the day!

A little bit more about the OTA, it's supposed to be an upgrade of their ED80, the coatings listed for that are SMC. They say nothing of the mating element and from what I've learned that one is what really decides the quality oi the scope.
Everyone likes to come up with a special name for their coatings but 99.9% of the time they the usual Magnesium Fluoride, the mating element will likely be some form of Lanthanum

So, most other triplets have two ED elements instead of one, most other triplets in the same category are made with FPL 53 instead of FPL 51. Don't know enough about what coatings SVBony uses, (may be SMC) and don't know anything about the mating element. Based on this knowledge, what we have here is a bargain basement triplet that should perform at least as well as my EvoStar Doublet, (uses the same glass).
The majority of triplets only use 1 ED element, the same with doublets. Their are a few triplets using 2 ED elements but is not common. ED elements when not specified could be FPL-51, 53, 55, FCD-1, 100, or FK-61. If they are going to use 51, 53 or 55 they will usually say. If they do not then it is likely they are using FCD-1, 100 or FK-61. Depending on the lens design and mating element(s) these will all produce good quality images so do not think one is superior to another.

So, to answer the question, no ma'am, they cannot.
Actually they can but it does not respect the consumer.

So, my final question is a scope worth $600 plus more for those two specs? No, buy a Skywatcher EvoStar 100ED, and save $600 plus which does actually fall into the focal length I'm wanting, though I am not looking to buy at this time.
The Skywatcher 100 f/9 is a very nice refractor even at the new higher price. I had one for a few years and enjoyed it.

I like the company for their support and cameras, I like their toy OTAs for use as a guide scope. The quality of the coatings on the toy scope are good. If I were just getting into astrophotography and these scopes were available, I would probably have bought one then. Marketing aside, decent entry level scopes at a decent price. Know what you're buying...
From reading on various NA and EU forums you were lucky as the general consensus is their costumer service still needs major improvement.
Absolutely nothing wrong with buying a decent beginners telescope at a good price. For quality per $/ € I would recommend looking at Bresser,
Teleskop-Service, APM or AstroTech, they are quite open about their optical packages and will provide extra information when asked.

Thank you again,
Clear Skies, Chris

[Bigzmey]

It is tricky to judge the scope just by the type of glass. Astrotech scopes have good reputation and they use FK-61 ED (FPL-51 equivalent). Pre COVID 127mm ES triplets were going for ~$1,500, also based on FPL-51 equivalent. Maybe SVBony pricing it aggressively to get marked share.

[SkyHiker]

For astrophotography there is now such an amazing toolset that you can probably get by with cheaper refractors. If you use filters it gets even better because software like PixInsight processes each filter separately and uses plate solving to make sure that the imaged objects of each color coincide at the exact same spot in the image, even when the refractor could have put them in different places. You could even get an achromat so long as you use filters. Software like BlurXTerminator will change blurry stars into pinpoint stars and will make the nebulosity pop. This blurring can be due to poor optics with deformations or poor tracking.

After using "honest" software like DSS and Gimp I switched to the dark side using PixInsight and BlurXTerminator. Not saying that the latter are "dishonest" but they use plate solving for correcting optical effects, and a library of images for AI learning that help improve the result. Some argue this is a step too far but hey, if the images are great, many might not care. Bottom line, unless you have top of the line equipment (mount and optics), using good processing tools blurs the distinction between cheap/beginner and medium/intermediate equipment.

[Lady Fraktor]

It is tricky to judge the scope just by the type of glass.

I agree Bigzmey though there are some basic parameters that can give a quite reasonable idea of how it should work.
Though I have refractors with OK-4, FPL-53 and Fluorite, my FK-61 doublet gives nothing up to them at all.

I had some down time at work today so read the CN thread about this telescope. 14 pages... so much stupid, so much cringe...
Even the SVBony page for this telescope has so much incorrect/ misleading and basic information missing.
Why do they keep comparing it to a 80 mm?? A apple to pineapple comparison, they must be the same as they both have apple in the name...

[Lady Fraktor]

I agree Henk, Chris (Leveye) used to take great images with a Stellarvue 80mm Nighthawk. (astro and nightscape)
For the AP enthusiast, as you say there are many tools available but unfortunately not for the visual enthusiast.
Be it a achromat or apochromat we are at the mercy of the seller and what they are willing to pay the manufacturer to build.