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Skywatcher 80ED pro or Skywatcher 150PDS?

Gohan75

By Gohan75
in Getting Started With Imaging

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ianpwilliams

ianpwilliams

Posted
Posted

Yeah I recon it's between the 130 and 150 (I'm just not keen on starting with an 80!). I've had a look at some 130PDS images on these forums:

http://stargazerslounge.com/topic/213817-130pds-or-150pds-as-a-first-imaging-ota/

There is one thing I'm confused about. This thread here (and others too), show some DSO's which fill the whole shot, and indeed are often too big for the shot. And then there are many other DSO shots where the the object is really small in the centre of the shot. Obviously different DSO's will be different distances, but is that all this is down to? Or is it down to something the imager has done? Or both? And are we basically talking about a very small percentage of the DSO objects being close enough for full shots (eg Orion Nebula, Andromeda Galaxy), and the vast majority being much further away, and therefore 150 and smaller FOV possibly veing the way to go?

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Chris

Chris

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There are just an handful of objects that fill the entire FOV of a widefield scope and then the apparent size of things starts to get small rather quickly! This is why I personally find the 750mm focal length of the 150p/pds pretty comfortable. The scope is only one side of the story though as it also depends on the size of the imaging sensor, the sensor on the DSLR is pretty large but some starter CCD cameras such as the Atik Titan have a very small sensor, the effect of this is that for example the planetary nebula M57 will look like a tiny ring with loads of space around it with a 130pds and a DSLR but it would look a lot more zoomed in with a 130PDS and an Atik Titan. 

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Alien 13

Alien 13

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The Andromeda galaxy is huge you would idealy need 200-400mm FL to get it in without going corner to corner again the Orion nebular with the running man is quite large but 400-700mm FL copes well with  it.

Alan

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ianpwilliams

ianpwilliams

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Interesting stuff, thanks.

This thread does seem to suggest that only the FL of the ED80 could capture all of the Andromeda Galaxy (and that the 130 and 150 couldn't), which is a shame because it just looks incredible to me. But that shouldn't really affect what scope I go for.

I do note that this thread talks about mosaics, which I'm guessing is taking two or more pictures and lining them up? But wouldn't that be unbelivably difficult to do? And wouldn't that mean (just as an example) taking 60 1-minute subs of half of the object, and then doing the same thing again for the other half? Because that whole process sounds like it could be pretty maddening!

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ianpwilliams

ianpwilliams

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http://stargazerslounge.com/uploads/gallery/album_2063/gallery_16129_2063_1972112.png

This M31 was taken with my old WO66 which has 388mm focal length, I cropped it a bit to help with the corners but only about an inch all the way round so hopefully it will give you some idea.

That is an amazing shot, and such a beautiful object. I would gladly spend a long cold evening outside if I could capture something like that!

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ChrisLX200

ChrisLX200

Posted
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I just bought a SW Equinox ED80 Pro. Although I confess its primary role will be mainly as a guiderscope (where it will be much better than the f/11 90mm Vixen leviathan I use with the SCT rig) I will try some wide-field shots with it too just to see how it performs.

ChrisH

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ianpwilliams

ianpwilliams

Posted
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Here's a comparison of the ED80, 130PDS and 150PDS.

And also a comparison of the Crab Nebula (just to see how they compare with something small). And yes I couldn't resist including the 200P in this one (and what a difference).

post-35725-0-34726400-1399056541_thumb.j

post-35725-0-99832900-1399056544_thumb.j

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ianpwilliams

ianpwilliams

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My opinion would be to go for the 150pds, because the vast majority of the DSO's do seem to be on the small side. That and the fact that people talk about how the 130pds can be awkward balance-wise with cameras etc on it because it's short. Adding a reticule for the 200pds was a bad idea because it seems like there's a massive increase from the 150pds. But I'm aware of the weight and wind sail issues that the 200pds can produce.

Anyway, referring back to my previous question:

I do note that this thread talks about mosaics, which I'm guessing is taking two or more pictures and lining them up? But wouldn't that be unbelivably difficult to do? And wouldn't that mean (just as an example) taking 60 1-minute subs of half of the object, and then doing the same thing again for the other half? Because that whole process sounds like it could be pretty maddening!

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swag72

swag72

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Anyway, referring back to my previous question:

I do note that this thread talks about mosaics, which I'm guessing is taking two or more pictures and lining them up? But wouldn't that be unbelivably difficult to do? And wouldn't that mean (just as an example) taking 60 1-minute subs of half of the object, and then doing the same thing again for the other half? Because that whole process sounds like it could be pretty maddening!

Yes that is exactly what you do for a mosaic. They are time consuming and at times maddening, but they really can increase your field of view. Take this for example, http://swagastro.weebly.com/uploads/2/3/3/7/23377322/heart_and_soul_mosaic_-_nb.jpg this is a 3x2 pane mosaic. Don't focus on M31 being the deciding factor for what you buy, there's a hell of a lot more out there than M31!!!

Here's a brief illustration about mosaics http://swagastro.weebly.com/building-a-mosaic.html

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swag72

swag72

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Great job! So how many subs of what duration did you use for each pane of that mosaic?

This was roughly 11-12 x 30 minute subs for each pane - But using 2 filters, so 5-6 subs per filter, per pane.

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Scott

Scott

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whilst I agree that many dso's are small, there are still plenty that require a wider field of view than is offered by a 6-8" newt. Yes mosaics are a great way to capture larger fields but anyone who has been living in the uk for the last year or so will realise just how slim the chances of getting a 7hr mosaic are, let alone a 70hr one. if I lived inSpain then this could be an option but as long as I'm here in "not so" sunny Stoke I won't be parting with my 60mm frac.

Having said that, geez, I'm so jealeous of Sara's work :D 

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ianpwilliams

ianpwilliams

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Yeah I do suspect that mosaics may not be much of an option here in the UK. I also agree that both the 130PDS and 150PDS both seem to be good, and that the 150PDS seems to be a good all-rounder for imaging and visual. I'm still tempted by the 200PDS through pure photon greed though! The heart says 200PDS and the head says 150PDS.

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Scott

Scott

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Yeah I do suspect that mosaics may not be much of an option here in the UK. I also agree that both the 130PDS and 150PDS both seem to be good, and that the 150PDS seems to be a good all-rounder for imaging and visual. I'm still tempted by the 200PDS through pure photon greed though! The heart says 200PDS and the head says 150PDS.

And we all know the heart usually wins :D. I've got the standard 200p and the 60mm frac and these don't come close to covering the options...Ideally, we'd all have a room full of 'scopes/cameras/mounts and just pick what's right for each object...sigh...can but dream 

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