Refractor 102/7 FPL51 vs. 80/7.5 FPL53

[tico]

Hi, 

In your opinión which is best for backyard astro? In AZ mount? 

For planets, Moon, Double Stars, and some brilliant Messier objects...? 

Thanks. 

Tico

 

[Space Hopper]

Aperture usually wins Tico.....

[mikeDnight]

For doubles and Messier objects the 102mm F7 has obvious advantages in terms of resolution and light grasp. It's only relatively recently that telescope manufacturers have started stating the glass types, and before that everyone was just happy to have a 4" refractor, never concerning themselves too much with the why's & wherefore's.  I've used numerous ED refractors around 102mm F7 from the period before the great glass type debate kicked off and they have been superb. I'd grab the 102mm and count myself lucky to have one. As an example, the Japanese company Vixen produced some great pre FPL53 ED's that would give any FPL53 or true Fluorite apo a run for their money. They were so good that I'm not even sure I could honestly tell the difference between an old Vixen or AstroTec and a modern FPL53 version visually. 

[John]

I would definitely go for the 102mm over the 80. For many years a 102mm F/6.5 ED doublet was my main telescope. 

Edited October 9, 2023 by John

[bosun21]

I can definitely tell the difference between the FPL51 and FPL53 refractors especially at high magnification. However the larger aperture wins out for me as well.

[paulastro]

Out of curiosity, a question for you refractorphiles.  Would you choose 110mm f6 StellaMira  (£799) with 'FPL-51 equivalent', or the Starfield 102mm F7 FPL53 (£899)? Presumably, according to the numbers of each sold most peoples choice is the latter?

I know what I think, though I'm not in the market so no money is involved 🙂.

Edited October 9, 2023 by paulastro

[Deadlake]

If going for an F6 scope I would want a triplet, I'd pick the slower scope for a doublet. At F6 it's hard enough with a Triplet design to get good colour correction.

A little off topic I did see this 125 mm doublet which comes with a Strehl of 0.95 on the green line.

https://astrograph.net/epages/www_astrograph_net.sf/en_GB/?ObjectPath=/Shops/www_astrograph_net/Products/AGTEC125F78

However back on topic also this one, gets good reviews on SGL and CN (Astrometrics brand),

https://astrograph.net/epages/www_astrograph_net.sf/en_GB/?ObjectPath=/Shops/www_astrograph_net/Products/AGTEC102F7
 

[Elp]

49 minutes ago, paulastro said:

Would you choose 110mm f6 StellaMira  (£799) with 'FPL-51 equivalent', or the Starfield 102mm F7 FPL53 (£899)? Presumably, according to the numbers of each sold most peoples choice is the latter?

The latter comes in many different guises from a number of brands and all I've read about give the same review, it's an excellent scope no matter the brand. I should know, it's the one I decided to get as a medium FL scope.

[John]

54 minutes ago, paulastro said:

Out of curiosity, a question for you refractorphiles.  Would you choose 110mm f6 StellaMira  (£799) with 'FPL-51 equivalent', or the Starfield 102mm F7 FPL53 (£899)? Presumably, according to the numbers of each sold most peoples choice is the latter?

I know what I think, though I'm not in the market so no money is involved 🙂.

I would go for the 102mm F/7 in that instance.

I recall when the William Optics Megrez ED 110 came out (which used the same glass types as the 110mm F/6 StellaMira I think) that the false colour visible surprised many people who tried one. 

 

[GTom]

Neither, get an at least 8" Newtonian or SCT. Aperture rulz. The nice and shiny APO's are great for deep sky astrophotography, but simply lack the light gathering and resolving power. 

Edited October 14, 2023 by GTom

[plyscope]

On 10/10/2023 at 05:37, paulastro said:

Out of curiosity, a question for you refractorphiles.  Would you choose 110mm f6 StellaMira  (£799) with 'FPL-51 equivalent', or the Starfield 102mm F7 FPL53 (£899)? Presumably, according to the numbers of each sold most peoples choice is the latter?

I know what I think, though I'm not in the market so no money is involved 🙂.

For a short while I owned both of these.  The Stellamira 110mm f6 is a great scope however for my use the Starfield ticks more boxes..

https://stargazerslounge.com/topic/399680-stallamira-110ed-f6-refractor/#comment-4288505

[mikeDnight]

On 09/10/2023 at 22:37, paulastro said:

Out of curiosity, a question for you refractorphiles.  Would you choose 110mm f6 StellaMira  (£799) with 'FPL-51 equivalent', or the Starfield 102mm F7 FPL53 (£899)? Presumably, according to the numbers of each sold most peoples choice is the latter?

I know what I think, though I'm not in the market so no money is involved 🙂.

I'd most likely go for the Starfield 102 FPL53 and forfeit the extra 10mm aperture of the StellaMira. The price difference is too close to be of much influence, so I'd go for the better optics over the minimal aperture gain, plus at F6, I imagine the StellaMira may be pushing its limits for colour correction. I'm sure it would be a nice scope for star fields and brighter deep sky though!

[mikeDnight]

On 14/10/2023 at 23:41, GTom said:

Neither, get an at least 8" Newtonian or SCT. Aperture rulz. The nice and shiny APO's are great for deep sky astrophotography, but simply lack the light gathering and resolving power. 

Moderator alert!  GTom mentioned "SCT" in the telescope discussion forum!!!  😲 Is that allowed, and do they count as telescopes?  😉😈

 

 

[Peter Drew]

They do, if you want something larger than a toy telescope that's still affordable.    🙂

[paulastro]

23 hours ago, Peter Drew said:

They do, if you want something larger than a toy telescope that's still affordable.    🙂

And Dobs of course Peter.  A cannon will always be better than a pea shooter for deep sky.  I keep my pea shooter (80ED) mainly for the sun. 🙂. 

In the dark world of imaging of course, a 50/60mm scope seems quite acceptable.

Edited October 18, 2023 by paulastro

[IB20]

What’s your average seeing like?

Is this a main scope or a grab n go quick look tool?

I would tend to err towards the 102 but would recommend the FPL53 models. They aren’t the lightest though and you need a sturdy tripod to ensure the mount is stable.

Ive compared a 3” Takahashi 76Q to a 102edr f7 and its fairly close on ordinary seeing days for solar system objects, only trouble is that’s it’s no ordinary 3” and suspect it’s well above any other 3” scope out there. The 102edr f7 is an absolutely wonderful scope however. 

If you’re in the UK, there’s a lovely looking TS 102 FPL53 currently on ABS at 2/3rds rrp.

[Deadlake]

On 17/10/2023 at 09:40, mikeDnight said:

Moderator alert!  GTom mentioned "SCT" in the telescope discussion forum!!!  😲 Is that allowed, and do they count as telescopes?  😉😈

 

 

I agree, I get bored waiting for my C11 to acclimate.

The C11 is a great scope for DSO's, however the stars will never be as sharp and pristine as an APO.

 

[Louis D]

On 18/10/2023 at 12:42, Deadlake said:

I agree, I get bored waiting for my C11 to acclimate.

The C11 is a great scope for DSO's, however the stars will never be as sharp and pristine as an APO.

 

Unless they're in a globular cluster, then then tend to just look like fuzz in most affordable refractors.  In a large Dob with a premium mirror, they break up at high power into twinkling crushed diamonds on black velvet, at least under Texas skies.

[Deadlake]

22 minutes ago, Louis D said:

Unless they're in a globular cluster, then then tend to just look like fuzz in most affordable refractors.  In a large Dob with a premium mirror, they break up at high power into twinkling crushed diamonds on black velvet, at least under Texas skies.

Sure, compare like with like. I would need a Lockheart mirror to compare with my APO’s and also a place to park a 20” dob. 😃

[John]

The views of globular clusters seem to improve with aperture more than most astro targets IMHO.

 

 

 

[paulastro]

I agree John. They are by far the clearest indication of the resolution of scopes of different apertures.  However good a four inch telescope is, it doesn't get beyond the fuzzy snowball stage for me when looking at globulars.

I feel that for a good all round telescope, a six inch aperture is the least that gives good views, of some examples, of the majority of different celestial objects.

 

[mikeDnight]

The trick to getting the best deep sky out of a smallish refractor is to get as well dark adapted as possible, and to observe an object at length from under a blackout hood or blanket. Ive seen some amazing subtle detail through my 4" refractors using this method, even seeing M13 as an explosion of stars right to the centre. The greatest challenge for me isn't the aperture of my refractor, it's the overlying haze that kills the view.

Edited October 19, 2023 by mikeDnight

[paulastro]

10 minutes ago, mikeDnight said:

The trick to getting the best deep sky out of a smallish refractor is get as well dark adapted as possible, and to observe an object at length from under a blackout hood or blanket. Ive seen some amazing subtle detail through my 4" refractors using this method, even seeing M13 as an explosion of stars right to the centre. The greatest challenge for me isn't the aperture of my refractor, it's the overlying haze that kills the view.

Mike, I think many people on this forum do have good observing techniques and a lot of experience.  Even some people who may think four inch aperture scopes don't cause  an explosion of stars right to the centre of globular clusters 😊.

 

Edited October 19, 2023 by paulastro
Typo

[Mr Spock]

From experience I'd recommend going the extra bit for a fpl-53 102mm refractor. On test the Starfield 102mm is almost identical in performance to a Tak FC100 with only subtle differences you wouldn't notice in isolation.

In addition to the optics the build quality is outstanding and is a scope you'll want to keep for a lifetime https://www.firstlightoptics.com/starfield-telescopes/starfield-102mm-f7-ed-doublet-refractor.html

[mikeDnight]

20 hours ago, paulastro said:

Mike, I think many people on this forum do have good observing techniques and a lot of experience.  Even some people who may think four inch aperture scopes don't cause  an explosion of stars right to the centre of globular clusters 😊.

 

That's true! Many but not all, and suggesting using a blackout blanket to achieve good dark adaption could help some to get far more out of their telescopes.  Having said that, years at the eyepiece is no guarantee of observing skill. I recently recieved the Web Societies latest journal in which the editor immediately begins by mocking the deep sky observing skill of some Cloudy Nights sketching contributors who use small telescopes, implying they're seeing too much detail. When I first read it I had to check that I hadn't joined the BAA by mistake.