Help - I can't decide on which 4" frac

[RobertI]

A couple of months ago I ordered a new toy - a Skywatcher ED100. My reason for choosing that scope at the time was that I have seen how people rave about their 4" apo's for visual and I have never owned or used one - I really want to find out for myself. Also I had never been totally happy with the 'yellow' colour cast in my Tal100R and want to see what a decent ED can do. I was planning to use for mainly planetary, lunar, doubles and clusters. I am not really expecting it to better the 150PL for planets, lunar and doubles, but I am expecting a better 'aesthetic' experience, and interested to see how important that is to me.

Unfortunately I am still waiting (due to long lead times) and have started to look at other options, and my new shortlist is below:

1. Skywatcher ED100 (£757, £555 for essential version) - Pros: Amazing value, proven performer, very low chance of a dud, light, good resale.   Cons: Questionable focuser, long scope with no sliding dewshield, low quality materials
2. TecnoSky 102 F7 FPL53  (£900) - Pros: Shorter with sliding dewshield, good focuser, better materials (more premium feel?), F7 gives wider fields, in stock I think.  Cons: Unknown quantity, probably harder to sell. 
3. StellaMira 80ED F10 (£900) - Pros: Superb build quality and focuser, top quality optics, zero chance of a dud (checked by ES Reid), looks gorgeous, something different, probably easy to sell, its in stock! Cons: 80mm might prove limiting, less good for wide fields, possibly expensive for what it is. 

I believe option 2 is also available branded by Teleskop Service and Altair Astro, so would expect the quality of optics to be good.

I am currently really keen on option 2, as F7 seems much more versatile (and portable) length and with my 38mm Panaview eyepiece, gives a 3.8 degree field and 5.5mm exit pupil, making it a really nice 'richest field' scope and also capable of fitting in the entire veil complex and other large objects. But also still capable for high power planets and doubles.

So head says option 2, heart says option 3 and wallet says option 1!!

Whatever I get I am hoping to use it at the dark skies of Kelling Heath in October.

What do people think? Are there any considerations I've missed? Are there other 4" apo options?

Rob

Edited August 30, 2020 by RobertI

[jetstream]

17 minutes ago, RobertI said:

Are there other 4" apo options?

Tak

[RobertI]

5 minutes ago, jetstream said:

Tak

LOL, yes I should have included my budget, £900 max! 😁 If this ‘experiment’ is a success though, my ultimate goal is a FC-100 of some sort. 

[jetstream]

1 minute ago, RobertI said:

If this ‘experiment’ is a success though, my ultimate goal is a FC-100 of some sort. 

I love experimenting too!

and have done a pile: my 90mm Stellarvue APO triplet is VG, going around 80x aperture or so, my SW 120ED beats the SV on faint nebs (the 90mm is so so) but doesn't go really high mag and has (had) a poor focuser (now Moonlight). 

My TSA 120 beats both in every aspect- very faint nebula (high throughput), lunar, planets ( it really good) and everything else.  It also works with a prism diag where the SW120ED does not. My sample of the SW120ED may not be typical? who knows.

All I'm gonna relate is the money I spent on these 2 scopes plus the focuser could have bought the TSA120 right off the bat or pretty close.

Experimenting is fun, but costly IME.

[johninderby]

The Tecnosky version is the same price as the TS one which would probably be easier to sell on.

https://www.teleskop-express.de/shop/product_info.php/info/p9868_TS-Optics-Doublet-SD-Apo-102-mm-f-7---FPL53---Lanthan-Objective.html

The SW 100ED is indeed a bargain although could do with a focuser upgrade and with the fixed dewshield takes up more room stored. 

.The StellaMira 80 F10 feels more like a 100 in use and makes a great lunar / planetary scope and has no noticeable CA. Noticeably sharper with more contrast than the SW doublets.

Hard to go wrong with any of them. 👍🏻

Edited August 30, 2020 by johninderby

[RobertI]

5 minutes ago, jetstream said:

All I'm gonna relate is the money I spent on these 2 scopes plus the focuser could have bought the TSA120 right off the bat or pretty close.

Experimenting is fun, but costly IME

Some great points there Gerry, I really ought to go straight to the Tak! Owners seem to get the same performance from the FC-100 as you would get from much bigger apo’s from other less premium brands. But given this is an experiment, perhaps I should go for the cheap option! 

[jetstream]

Just now, RobertI said:

. But given this is an experiment, perhaps I should go for the cheap option! 

Yes its fun, it might be wise to choose the most marketable scope for re sale. The Tak 100's have an extremely good reputation. My 90mm APO is a very capable lunar/planetary/doubles scope with little or no scatter. I think its a re branded Long Perng- something like FLOS StellaMira? Their scope is most likely a step up from mine.

Have fun! Eagerly waiting to see what you buy!

[RobertI]

5 minutes ago, johninderby said:

Hard to go wrong with any of them. 👍🏻

Thanks John, I know you’ve had a great experience with the StellaMira so far, and that counts for a lot. I think the optics are really top notch. I guess I was worried that 80mm would not be much different to the 72mm F6 ED that I just sold, but in reality I guess the StellaMira is a completely different animal. 

[johninderby]

All I can say it’s a scope that has that “Wow” factor when you look through it. 🙂

[RobertI]

2 minutes ago, johninderby said:

All I can say it’s a scope that has that “Wow” factor when you look through it. 🙂

I am very drawn to the prospect of something unique and unusual. And I guess when buying from FLO I know I can return it in the unlikely event I find it disappointing. I suspect if I did like it, it would be a keeper.  One thing I do wonder though, is how much of that cost is because Long Perng don’t sell many of them, rather than because the optics are premium quality? I guess I can only find out by looking through one!!

[johninderby]

If I ever did replace the StellaMira it would be with a Tak FC100DZ.😁

Edited August 30, 2020 by johninderby

[RobertI]

1 minute ago, johninderby said:

If I ever did replace the StellaMira it would be with a Tak FC100DZ.😁

Wouldn’t we all? 😂😂
 

But I take your point. 

Edited August 30, 2020 by RobertI

[dweller25]

Having directly compared a 100ED to a 4” Tak triplet I can say that the Skywatcher 100ED is at least 90% of the performance for 25% of the price.

BUT your 150PL will probably match the planetary views of the ED and the C8 will probably beat it.

if you really want great views buy a 10” Dob 👍

Edited August 30, 2020 by dweller25

[Dantooine]

I use one of these and love it

[RobertI]

5 minutes ago, dweller25 said:

Having directly compared a 100ED to a 4” Tak triplet I can say that the Skywatcher 100ED is at least 90% of the performance for 25% of the price.

BUT your 150PL will probably match the planetary views of the ED and the C8 will probably beat it.

if you really want great views buy a 10” Dob 👍

Good points, and thanks for sharing your experiences. I suspect that ultimately I will end up with a premium frac and a  10” - 12” Dob as my main scopes, but I think that’s a few years away. Good to know about your positive experience of SW ED100. 

[RobertI]

2 minutes ago, Dantooine said:

 

I use one of these and love it

 

I think that is effectively my option 2 (same lens I think) - thanks, reassuring to know you’re happy with it. 

[John]

Personally I would stick to 100mm as a minimium aperture. I've owned some good quality ED doublets of, 70mm, 80mm and 90mm but, for me it's 100mm and above which deliver views that are engaging enough to be more than just "nice".

The Skywatcher ED100 is a great scope for the money IMHO. I owned one of the very early blue tubed ones. Now my "100's" are the Vixen ED102SS F/6.5 and the superb Tak FC100-DL F/9. Both very capable scopes at low, medium, high and, in the case of the Tak, very high magnifications.

F/7 is a versatile focal ratio for an ED doublet. Slow enough to cause CA to be mostly invisible if an FPL-53 element is used but fast enough to get whopping true fields with long FL 2 inch eyepieces.

 

[Dantooine]

1 minute ago, RobertI said:

I think that is effectively my option 2 (same lens I think) - thanks, reassuring to know you’re happy with it. 

Yep same I reckon. Nice focuser and dew shield slides/floats nicely. You wouldn’t feel you’d missed out.  

[Dantooine]

6 minutes ago, Dantooine said:

Yep same I reckon. Nice focuser and dew shield slides/floats nicely. You wouldn’t feel you’d missed out.  

Oh yeah, I forgot to mention the glass is pretty good too 😂

Edited August 30, 2020 by Dantooine

[Chris]

With my head I'd go for option 2 mate   Probably the Altair or TS version of the fpl53 102 f7. If had to live with one scope, this probably would be it! (weighing up every single factor I can think of). 

With my heart I'd choose the Stella Mira 80mm f10. I have moments where I really want this scope - I know it would be practically optically perfect and the views would be very aesthetically pleasing and the user experience would be nice looking at the fit and finish. 

It's a tricky one Rob!  

[Dantooine]

So there you have it, you are down to a choice of the 3 scopes you mentioned... we are all the same as you. You can’t really make the wrong choice unless........,,

[RobertI]

5 minutes ago, John said:

Personally I would stick to 100mm as a minimium aperture. I've owned some good quality ED doublets of, 70mm, 80mm and 90mm but, for me it's 100mm and above which deliver views that are engaging enough to be more than just "nice".

Thanks John, yes that was my concern. My Tal 100RS hasn't made me an instant convert to 4" fracs , and there is a risk that a smaller aperture ED won't do it either, but a 100mm ED just might.....

11 minutes ago, John said:

F/7 is a versatile focal ratio for an ED doublet. Slow enough to cause CA to be mostly invisible if an FPL-53 element is used but fast enough to get whopping true fields with long FL 2 inch eyepieces.

Yes that was my thinking, given the other scopes in my collection, none of which can take 2" eyepieces (apart from the Tal), an 100mm F7 ED frac would offer me much wider fields than I can currently achieve. It just 'feels' right.

[RobertI]

15 minutes ago, Lockie said:

With my head I'd go for option 2 mate   Probably the Altair or TS version of the fpl53 102 f7. If had to live with one scope, this probably would be it! (weighing up every single factor I can think of). 

With my heart I'd choose the Stella Mira 80mm f10. I have moments where I really want this scope - I know it would be practically optically perfect and the views would be very aesthetically pleasing and the user experience would be nice looking at the fit and finish. 

It's a tricky one Rob!  

Thanks Chris, good to hear, I think I remember you singing the praises of the F7 100mm ED, which has influenced me somewhat! The ease/value of resale of the TS/Altair/Tecnosky does bother me, but I don't have much of a history of selling my stuff so would probably keep it. However it would also be the most expensive single piece of astro equipment I have ever bought, so I would want it to feel special.

The Astrograph website says "As with all telescopes supplied by Astrograph, the <insert scope name> is supplied only after careful inspection and being fully aligned and star tested." If this is true, it provides some reassurance. I've not dealt with Astrograph so cannot varify their credentials. I guess TS are a large supplier who should take the scope back if there was a problem.

[johninderby]

[RobertI]

1 minute ago, johninderby said:

I resemble that remark!