I need help trying to decide frac vs newt for imaging

[Orion1]

I'm upgrading from a Canon 200mm f2.8L lens. I have a Skywatcher EQ5 Synscan mount and a Canon 600D full spectrum with a Astronomik CLS-CCD) camera.

I need help because I'm stuck trying to decide whether to buy the TS 80mm triplet with reducer or the Skywatcher 130PDS with coma corrector.

I love the nimble form factor of the 80mm triplet but the price/performace ratio of the 130PDS is giving me a headache...

[scitmon]

I think the triplet refactor would win in nearly all areas, except cost and maybe weight.  The 130PDS is certainly no slouch as I have seen from this thread: 

 so I think you need to decide yourself whether the cost of a triplet refractor is worth the extra cost.

 

I think you need to consider your mount more than scope.  Your Eq5 is not really upto the job of serious Astrophotography in my opinion, perhaps the cheaper 130PDS and putting the extra money towards a better mount is the way to go?

[Orion1]

Thanks! Personally I think the EQ5 is good enough up to 130PDS for imaging but it is the limit.

The thread Image with 130PDS is what made me think twice about the triplet.

[ollypenrice]

I think that if we took an expertly collimated and fine tuned 130PDS it would beat the little apo. With all twists out of its spider, an orthognal, tilt-free focuser and spot-on collimation then, yes, I do think the Newt would win.

But will you get the Newt to that stage and how long will it take you to do so? And if you don't? There's the rub.

I'm an imaging provider and have made an informed and conscious choice to run refractors because they just work. And because, having six observatories on site, I am absolutely not looking for any additional 'tinkering entertainmant!' 

The Newt wins on price and, in a perfect world, on performance. The refractor may prove better at negotiating with reality!

Olly

[Orion1]

19 minutes ago, ollypenrice said:

I think that if we took an expertly collimated and fine tuned 130PDS it would beat the little apo. With all twists out of its spider, an orthognal, tilt-free focuser and spot-on collimation then, yes, I do think the Newt would win.

But will you get the Newt to that stage and how long will it take you to do so? And if you don't? There's the rub.

I'm an imaging provider and have made an informed and conscious choice to run refractors because they just work. And because, having six observatories on site, I am absolutely not looking for any additional 'tinkering entertainmant!' 

The Newt wins on price and, in a perfect world, on performance. The refractor may prove better at negotiating with reality!

Olly

Thanks Olly, I’m done tinkering. Astrophotography is enough tinkering as it is  Sounds like a triplet is the way to go for me.

[Thalestris24]

19 hours ago, Orion1 said:

I'm upgrading from a Canon 200mm f2.8L lens. I have a Skywatcher EQ5 Synscan mount and a Canon 600D full spectrum with a Astronomik CLS-CCD) camera.

I need help because I'm stuck trying to decide whether to buy the TS 80mm triplet with reducer or the Skywatcher 130PDS with coma corrector.

I love the nimble form factor of the 80mm triplet but the price/performace ratio of the 130PDS is giving me a headache...

Hi

You might like to consider the APO just with a flattener as it would then give a narrower, if slightly 'slower' F6 (compared to using  a reducer) though clearly not so narrow as the F5 130pds. I have the TS 80mm APO and a 130pds. The latter I put to one side as I don't have the engineering space or skills or time to fiddle with it! The APO is very well made and probably worth the extra expense. It obviously doesn't have a 130mm aperture but it's compact and easy to handle

Louise

[emyliano2000]

I'm quite new to refractors as I recently got a really good deal (£400) on a little "as new" f6.5 ts 65 quad and I own a f5 200p reflector too. I love them both the same as I always wanted a scope for narrow fov and one for wider fov. A reflector does take a lot of tinkering indeed and even though my one is quite big, I love it because of the little diffraction spikes on the stars and the narrow fov for some smaller targets. As for the refractor I love it because it's very light and setting it up is quite straightforward. If you're not into tinkering I would suggest a refractor and in the future, who knows, maybe you will get a reflector too for a narrower fov and for your tinkering pleasure as the used ones can be quite cheap.  ?

Emil

[Orion1]

51 minutes ago, emyliano2000 said:

I'm quite new to refractors as I recently got a really good deal (£400) on a little "as new" f6.5 ts 65 quad and I own a f5 200p reflector too. I love them both the same as I always wanted a scope for narrow fov and one for wider fov. A reflector does take a lot of tinkering indeed and even though my one is quite big, I love it because of the little diffraction spikes on the stars and the narrow fov for some smaller targets. As for the refractor I love it because it's very light and setting it up is quite straightforward. If you're not into tinkering I would suggest a refractor and in the future, who knows, maybe you will get a reflector too for a narrower fov and for your tinkering pleasure as the used ones can be quite cheap.  ?

Emil

Tape a thin thread in cross on the front of the aperture of your frac and you get little diffraction spikes...

[emyliano2000]

14 minutes ago, Orion1 said:

Tape a thin thread in cross on the front of the aperture of your frac and you get little diffraction spikes...

I can add them in photoshop too with the Noel Carboni's astrotools but for small targets I will still use my newtonian ?

[serbiadarksky]

Im not an scope expert, but why nobody use the 150/750 newton?

Its f5 so still fast 

[Thalestris24]

24 minutes ago, serbiadarksky said:

Im not an scope expert, but why nobody use the 150/750 newton?

Its f5 so still fast 

Some people do! but they are relatively big and heavy...

Louise

[Orion1]

8 hours ago, serbiadarksky said:

Im not an scope expert, but why nobody use the 150/750 newton?

Its f5 so still fast 

I wish but it’s too big for EQ5

[happy-kat]

Doesn't it also have a narrower field of view over the 130 flavour.

[Orion1]

12 minutes ago, happy-kat said:

Doesn't it also have a narrower field of view over the 130 flavour.

Too narrow for me anyway as I currently using 200mm

[ronin]

I would be a little concerned by the weight. People do use an 80mm but that is often the Skywatcher and they are doublets, you would have an extra lump of glass at the front to swing round and you have a lump of DSLR at the rear.

The people a I knew of that used EQ5's a lot used WO 72mm scopes, so a reasonable amount smaller and lighter.

All the little seemingly insignificant bits eventually add up although the EQ5 is a fairly solid mount. Do you intend to add guiding in at some future time?

[Orion1]

The 80mm triplet is about 3,5kg plus guide scope and camera about 1kg and dslr 650g. I think it’ll work fine with EQ5 to start with.

[spillage]

2 hours ago, happy-kat said:

Doesn't it also have a narrower field of view over the 130 flavour.

Yes it does have a smaller fov. Not much but enough to bother me on large targets. Great for smaller nebula though. It is surprising how much more it weighs though.

[Adam J]

The 130PDS is from my experience a great scope and is unbeatable in terms of price per performance. It will work right out of the box, however, if you want the very best from it then you will need to do some tweaking. 

[Orion1]

33 minutes ago, Adam J said:

The 130PDS is from my experience a great scope and is unbeatable in terms of price per performance. It will work right out of the box, however, if you want the very best from it then you will need to do some tweaking. 

Looking at fov-calculator I think maybe 650mm is a little bit too narrow for big objects and too short for the smaller. coming from 200mm a triplet with reducer is about 400mm which will keep me busy for a long time.

[Orion1]

I’m sorry my mount is a CG5 not a EQ5. But they are equal in load capacity?

[ollypenrice]

Don't obsess about load capacity. What experience will tell you is that the resolution of your imaging setup in arcseconds per pixel is what tests the limits of your mount. The fewer arcsecs per pixel at which you're imaging, the more accurate your mount has to be. It is this which is the most important thing.

Olly

[serbiadarksky]

13 hours ago, Orion1 said:

I wish but it’s too big for EQ5

Too bih for eq5?

I saw several of them on eq3-2 producing awesome images!

[Orion1]

12 hours ago, ollypenrice said:

Don't obsess about load capacity. What experience will tell you is that the resolution of your imaging setup in arcseconds per pixel is what tests the limits of your mount. The fewer arcsecs per pixel at which you're imaging, the more accurate your mount has to be. It is this which is the most important thing.

Olly

Thanks, Olly I agree. I’m not at all obsessed with load capacity  I think I’ll be fine with both triplet or 130PDS on CG5/EQ5. I’ve seen good results with larger fracs on EQ3 and people are even producing wonderful images using smaller fracs with Star Adventurer.

I know mount is important. But seems like almost everytime someone is asking for scope advice the discussion end up in a mount discussion. So regarding mount I will work with what I have and upgrade later.

I’ve been working with my Canon 200mm for two seasons now and I’m tired of the focal length. Sure I could buy a better mount, but then I’ll still stuck with my 200mm Canon lens and gain nothing. Right now I can’t afford both.

[Gerry Casa Christiana]

On 06/12/2017 at 22:11, ollypenrice said:

Don't obsess about load capacity. What experience will tell you is that the resolution of your imaging setup in arcseconds per pixel is what tests the limits of your mount. The fewer arcsecs per pixel at which you're imaging, the more accurate your mount has to be. It is this which is the most important thing.

Olly

Hi Olly

Can I just ask what is considered good in arc seconds for deep sky stuff. I'm doing 1.18 arcseconds per pixel. Is there a sweet spot or a area I should be aiming for? Or is it just a case the smaller you go the more accurate you need to be? Sorry I'm not so technical as you  but would love to be. 

Thanks 

Gerry

[ollypenrice]

5 hours ago, Gerry Casa Christiana said:

Hi Olly

Can I just ask what is considered good in arc seconds for deep sky stuff. I'm doing 1.18 arcseconds per pixel. Is there a sweet spot or a area I should be aiming for? Or is it just a case the smaller you go the more accurate you need to be? Sorry I'm not so technical as you  but would love to be. 

Thanks 

Gerry

The debate is undecided, Gerry. I have an open mind, having taken images which I have enjoyed processing at anything between 0.66 and 3.5 arcseconds per pixel. To be honest, If I could find a camera with the chip size of the Atik 11000 (3.5"PP for me) that gave me 2"PP I'd sell someting precious and buy it! But it doesn't exist...

3.5"PP...

1.8"PP...

0.9"PP...

They're all pictures...

Olly