Stella Mira 80mm F10

[Portech7]

Having reflectors for wide field astrophotography, would the Stella Mira 80mm F10 doublet with FPL53 be good for smaller deep sky objects with a hypercam 294C pro? Or is it focused on visual? 

The telescope/ camera compatibility seams to say its compatible, but anyone using one of these scopes? 

TIA😁

 

Edited July 25, 2022 by Portech7

[Adam J]

25 minutes ago, Portech7 said:

Having reflectors for wide field astrophotography, would the Stella Mira 80mm F10 doublet with FPL53 be good for smaller deep sky objects with a hypercam 294C pro? Or is it focused on visual? 

The telescope/ camera compatibility seams to say its compatible, but anyone using one of these scopes? 

TIA😁

 

F10 is generally too slow optically to make a good imaging scope.

Edited July 25, 2022 by Adam J

[Portech7]

The thing I'm struggling with is that I have only really used reflectors, but fancy a change as mine are getting a bit worse for wear and fancy something I can get deeper with for small galaxy and clusters. 

I've been bouncing back and forth with a 102mm F7 refractor but for my price range it's with FPL51, an RC6 but then worry about the focuser as it's not rack and pinion and could slip, or go for a smaller aperture refractor but better glass and focuser. 

Not sure what's best to be honest. 

Edited July 25, 2022 by Portech7

[Skyline]

My 2ps worth:

Fast scope, DSLR

Slow scope, Sensitive Camera.

[Portech7]

I know what you mean, I used a mod'd 1100D with my f5 reflectors and it done well, but my 294c pro is definitely more sensitive and I haven't seen a smidge of amp glow. 

Think it would fit well with a refractor. 

[Adam J]

1 hour ago, Portech7 said:

I know what you mean, I used a mod'd 1100D with my f5 reflectors and it done well, but my 294c pro is definitely more sensitive and I haven't seen a smidge of amp glow. 

Think it would fit well with a refractor. 

If you are specifically wanting something for smaller targets and you can afford a stellamira 80mm F10 then if it was me I would honesty be looking at a 150mm F5 Newtonian. Maybe one of the TS optics ones. But if you want a refractor in your price range then that's more difficult. 

https://www.firstlightoptics.com/starfield-telescopes/starfield-102mm-f7-ed-doublet-refractor.html

The starfield 102 F7 would be my choice. 

Adam 

[Skyline]

A 6" F5 Reflector is a formidable choice, be it used with a dslr or a sensitive camera, more buck for your money.

The TS ones have a better coating on the mirrors compared to the skywatchers or if you can get hold of a celestron 150xlt Reflector the starbright xlt coatings were very good and nor do I follow the opinion the coatings are the same as the skywatchers.

Mind you the TS Optics also get mirrors made by GSO. So I don't see any difference between a TS, Altair or Stellalyra.

Edited July 25, 2022 by Skyline

[Clarkey]

The other thing to consider is the mount. For the longer FL you will need good tracking.

What about the SM 110mm F6 doublet? Slightly more money but probably better suited to AP and a good price.

[Adam J]

11 hours ago, Clarkey said:

The other thing to consider is the mount. For the longer FL you will need good tracking.

What about the SM 110mm F6 doublet? Slightly more money but probably better suited to AP and a good price.

I dont see that as being an imaging scope more wide feild visual. You are going to see significant blue bloat from a  110mm FPL-51 doublet at F6

Adam 

[Clarkey]

29 minutes ago, Adam J said:

I dont see that as being an imaging scope more wide feild visual. You are going to see significant blue bloat from a  110mm FPL-51 doublet at F6

There will undoubtedly be some CA at F6, but nothing that could not be removed relatively easily in processing or with an L3 filter. However, looking at the specifications again the Starfield is probably a better bet.

I do think there is a bit of an obsession with FPl-53 over FPL-51. A well made FPL-51 is likely to perform as well as 53

[KP82]

10 minutes ago, Clarkey said:

There will undoubtedly be some CA at F6, but nothing that could not be removed relatively easily in processing or with an L3 filter. However, looking at the specifications again the Starfield is probably a better bet.

I do think there is a bit of an obsession with FPl-53 over FPL-51. A well made FPL-51 is likely to perform as well as 53

It's not only the blue bloat, but there is also loss of the details due to CA and SA with a fast ED doublet like the 110mm f/6.

Sampling with an IMX294 at 660mm with detail loss due to CA, SA and seeing, I believe the end result would be quite soft. As for the exact maths, you will have to ask @vlaiv for help.

[Clarkey]

12 minutes ago, KP82 said:

It's not only the blue bloat, but there is also loss of the details due to CA and SA with a fast ED doublet like the 110mm f/6.

Sampling with an IMX294 at 660mm with detail loss due to CA, SA and seeing, I believe the end result would be quite soft. As for the exact maths, you will have to ask @vlaiv for help.

I don't disagree with any of the comments - I was just looking at options, but to a price. Given the OP original budget and FL requirement it would still be an option in my opinion. With a flattener reducer it would also give quite a fast system for AP.

Personally I would go with the RC6 with a suitable flattener/reducer and bin the camera. This would remove the false colour and give a fast system at a good sampling rate. Good value too.

[Adam J]

2 hours ago, Clarkey said:

There will undoubtedly be some CA at F6, but nothing that could not be removed relatively easily in processing or with an L3 filter. However, looking at the specifications again the Starfield is probably a better bet.

I do think there is a bit of an obsession with FPl-53 over FPL-51. A well made FPL-51 is likely to perform as well as 53

Its not just the CA in itself, yes you can remove that during processing but in the end it makes the Luminescence channel less sharp because blue photons are not going exactly where you want the to go, same is true for OSC imaging when you cant refocus between RGB filters. Less important for wide field nebula work especially in narrow band, but as the OP has stated small targets (galaxies most likely) then sharpness is going to be a factor in picking up detail and if you don't have to use the L3 you are going to get allot more of those nice blues we want to see in spiral arms. I have a FPL-51 equivalent scope in the form of the FMA180 but that is very much a wide field instrument and using a L3 filter is valid. 

The often quoted "a good FPL-51 scope will outperform a poor FPL-53 scope" scenario basically relies on someone making a poor FPL-53 design, in this day and age of computer lens design and improved polishing methods you would have to try pretty hard to find such a scope. Hence, given the choice for imaging FPL-53 / FPL-55 / FCD-100 is the way to go. Moreover we know that the Starfield 102 is a good design in this case and that the above argument doesn't apply are a result. 

The other nice thing about a 4 inch F7 is that they reduce nicely to F5.5 for wider field use also. A 102mm F7 scope with access to both flatterer and reducer is a versatile imaging tool. 

Adam

 

Edited July 26, 2022 by Adam J

[Clarkey]

18 minutes ago, Adam J said:

Its not just the CA in itself, yes you can remove that during processing but in the end it makes the Luminescence channel less sharp because blue photons are not going exactly where you want the to go. Less important for wide field nebula work especially in narrow band, but as the OP has stated small targets (galaxies most likely) then sharpness is going to be a factor in picking up detail and if you don't have to use the L3 you are going to get allot more of those nice blues we want to see in spiral arms. I have a FPL-51 equivalent scope in the form of the FMA180 but that is very much a wide field instrument and using a L3 filter is valid. 

The often quoted "a good FPL-51 scope will outperform a poor FPL-53 scope" scenario basically relies on someone making a poor FPL-53 design, in this day and age of computer lens design and improved polishing methods you would have to try pretty hard to find such a scope. Hence, given the choice for imaging FPL-53 / FPL-55 / FCD-100 is the way to go. Moreover we know that the Starfield 102 is a good design in this case and that the above argument doesn't apply are a result. 

The other nice thing about a 4 inch F7 is that they reduce nicely to F5.5 for wider field use also. A 102mm F7 scope with access to both flatterer and reducer is a versatile imaging tool.

As I said in my post above - I don't disagree at all, I was just giving options.

I would still question the FPL-51 vs FPL-53 mainly down to the manufacturing tolerances at this price point - not specifically down to design but down to individual scopes. I have an ED80 which is FPL-53 and this gives a fair bit of blue bloat and generally this is deemed 'good' optically for the money. Mine was also optically checked by FLO.

[Zeta Reticulan]

16 hours ago, Skyline said:

 

Mind you the TS Optics also get mirrors made by GSO. So I don't see any difference between a TS, Altair or Stellalyra.

A lot of Altair and TS Newtonians are literally rebadged GSO.

[Skyline]

16 hours ago, Clarkey said:

As I said in my post above - I don't disagree at all, I was just giving options.

I would still question the FPL-51 vs FPL-53 mainly down to the manufacturing tolerances at this price point - not specifically down to design but down to individual scopes. I have an ED80 which is FPL-53 and this gives a fair bit of blue bloat and generally this is deemed 'good' optically for the money. Mine was also optically checked by FLO.

I have a celestron C80ED and C100ED with FPL53 both do not exhibit any blue bloat. The C100ED is a nice scope for imaging galaxies and globs, same similar to the Celestron XLT150 f5 Reflector i have.

Couple the 100ED with a reducer brings it down to f7.6 , just add a sensitive camera into the mix and there you go, now you have a scope setup near to the starfield f7.

Or couple the Reflector with a sensitive camera and a coma corrector -  there you go - No CA, True Star Colour, No Bloat, No worries about what glass the scope has, you have a small central obstruction as the secondary is around 48-50mm how much that would impede on contrast I would think be minimal, compared to some secondaries which are around 63mm. A lighter scope for the mount.

Just my 2ps worth.

 

Edited July 27, 2022 by Skyline

[Portech7]

Update,, managed to get myself a 115mm F7 Apo, so very chuffed. 👍

 

Thanks all 👌