Astrophotography image vs viewing image...examples of the difference?

[Seamaster]

Hi, whilst I muck about deciding on a scope I wondered if it were possible see the difference between a viewed object I.e. Mars, Jupiter etc and a photograph!

Now I know that photos are enhanced and such and so will always look sharper and more colourful than a straight view from the scope. I also realise that different eyepieces will give different results but let's assume everything else is equal except for the fact one is imaged and the other viewed straight from the scope?

But exactly how much difference will there typically be?

I know it sounds daft but are there any images that are true to the veiwfinder that will show me what to expect and to hopefully manage my expectations.

I hope to be using either a 6" Mak/Schmidt Cassegrain or perhaps a 8" SW 200P?

Thanks.

Neil.

[Guest CodnorPaul]

http://stargazerslounge.com/topic/196278-what-can-i-expect-to-see/

 

Have a look here - best I have found

[Tweedledee]

That SGL thread is excellent.

Not seen that before.

Thanks.

[Brantuk]

In terms of planets the difference is mostly down to size and stability. What you see in the eyepiece will appear to wobble a lot due to atmospheric disturbance. Every now and then it settles for a second or so and if your eyes are dark adapted and accustomed to star gazing and the scope is set up well, you can just make out extra details like the GRS on Jupiter or Cassini Division of Saturn's rings in those brief moments of steadiness. Planets also appear very bright and very small but larger surface features like Jupiter's bands are very easy to see even when it's wobbling.

 

A photo of a planet however is usually taken with a fast frame rate camera that captures all the momentary steady frames. So when the duff frames are expunged and the remaining ones stacked and processed together, you get a very clear and magnified photo that's full of colour.

 

DSO's when viewed at the eyepiece on the other hand are black/white/grey and stars are sparkly points of white light. You can however perceive colour in some objects like Albireo (double star) which is clearly gold and blue. Nebulae are multi shade grey clouds, galaxies have shape and brightness levels but all in black and white, and clusters are glittery light points.

 

You can notice Betelgeuse has a red'ish hue, but I'm not sure if that's a trick of the eye, otherwise everything is too far away for the human eye to see colour. A photo of course can bring it all out if exposed for long enough and processed properly. This is why observing benefits from larger apertures collecting as much light as possible to raise the sharpness and contrast of b/w/g objects.

[Toymaster]

In terms of planets the difference is mostly down to size and stability. What you see in the eyepiece will appear to wobble a lot due to atmospheric disturbance. Every now and then it settles for a second or so and if your eyes are dark adapted and accustomed to star gazing and the scope is set up well, you can just make out extra details like the GRS on Jupiter or Cassini Division of Saturn's rings in those brief moments of steadiness. Planets also appear very bright and very small but larger surface features like Jupiter's bands are very easy to see even when it's wobbling.

 

A photo of a planet however is usually taken with a fast frame rate camera that captures all the momentary steady frames. So when the duff frames are expunged and the remaining ones stacked and processed together, you get a very clear and magnified photo that's full of colour.

 

DSO's when viewed at the eyepiece on the other hand are black/white/grey and stars are sparkly points of white light. You can however perceive colour in some objects like Albireo (double star) which is clearly gold and blue. Nebulae are multi shade grey clouds, galaxies have shape and brightness levels but all in black and white, and clusters are glittery light points.

 

You can notice Betelgeuse has a red'ish hue, but I'm not sure if that's a trick of the eye, otherwise everything is too far away for the human eye to see colour. A photo of course can bring it all out if exposed for long enough and processed properly. This is why observing benefits from larger apertures collecting as much light as possible to raise the sharpness and contrast of b/w/g objects.

 

Well put Kim - Exactly how I am finding it as a relative beginner.

 

Ade

[Seamaster]

Thanks for the comprehensive replies, I think I get the gist of it.

So, irrelevant of the GoTo vs not thing and for purely viewing purposes would say a 8" SW 200P be more "rewarding" than a 6" Celestron or

6SE ?

(the 8" Celestron 8SE is out of budget even second hand on the SCT style but not on the Newtonian.

I have been offered a Celestron 6SE opened but claimed unused (and therefore as new) for £635 plus shipping.

It only includes what usually comes with it except for a Celestron Star Diagonal-1 1/4 model #94115-A.

Not sure what that is and if I need one?

That would (depending on delivery/courier costs) leave me around £100 to spend on a power adaptor, an eyepiece and a couple of filters perhaps?

Does that sound a good deal to you?

Edited June 7, 2014 by Seamaster

[BAZ]

The scopes you are looking at both perform very well, they are though different animals. The 6SE has a focal length of 1500mm and an aperture of 5.9", this gives you F10. The 200P is F5.9.  The only problem with faster optics than around F5 is that you need very well corrected eyepieces, and these are costly. The SCT will be a superb Planet an Lunar scope, but will not tease out the detail in the dimmer DSO's.

Most DSO's tend to be large and faint, so the narrower field of view the SCT has won't show them too well. 

The Dob is good at the Moon and Planets, but brings out the fainter stuff better due to it's larger aperture. If you are visual, then aperture wins hands down every time, the only exception to this is Solar system objects, then the longer focal length gives better contrast and sharper views.

 

Planets/Moon versus Deep Sky Objects, That is pretty much the demarcation for visual observing.

I think Kim used a good analogy and used cars as a comparison. A Ferrari goes quick, but not over a ploughed field, you need a Land Rover for that.

 

I would echo the previous advise, have a look through different scopes before you buy, it will quickly show what they are capable of. 

 

Edit.

While it's raining, have a play with the ocular function in Stellarium, compare the two scopes and what effect different eyepieces have on the same objects. It's not a proper comparison, but would give you some idea of what to expect.

Edited June 7, 2014 by BAZ

[Toymaster]

The scopes you are looking at both perform very well, they are though different animals. The 6SE has a focal length of 1500mm and an aperture of 5.9", this gives you F10. The 200P is F5.9.  The only problem with faster optics than around F5 is that you need very well corrected eyepieces, and these are costly. The SCT will be a superb Planet an Lunar scope, but will not tease out the detail in the dimmer DSO's.

 

 

 

That's interesting Martyn,

So a low F4.5 Dob requires better quality EPs than say a F11 Mak?

 

Could explain why I'm seeing such a difference since I purchased better EPs

 

Cheers,

 

Adrian

[Brantuk]

Tut! Forgetting all I taught you Ade? hahaha!

[BAZ]

It's simply down to the ability of the eyepiece to pass as much, and a correct path of light through to your eye. The cheap zoom eyepieces have a really restricted field stop, (less than 48 degrees) it's like looking down a damp bog roll, whereas the better quality zoom eyepieces are far better, giving up to and sometimes beyond 68 degrees field of view. The better the scope, the better the eyepiece needed. Yes you can get a good view through a bog standard eyepiece, but a bloody superb view through a top quality one. (Ask Daz !)

However, the longer focal length scope you have, the more forgiving this is to lesser eyepieces. 

This gets into a whole new debate. 

The quality of eyepieces. There are some really good cheaper end eyepieces which hold their own against the medium and higher end ones. The problem common to all these is the limitations of our own eyes, this is where it gets subjective to the viewer.

I have had a look through some premium eyepieces, and they are for my eyeball are difficult to get on with. The medium end eyepieces for me provide the field view and exit pupil Iam really comfortable with.

As with scopes, have a look through some before you buy. The difference is people keep eyepieces, but change scopes!

[Guest]

With my results, I sometimes get more detail visually and others I get more detail photographically. I've recently acquired the ability to take longer exposure photographs of deep sky objects but need the right weather conditions before my bedtime before I can use it.

I find with long exposures of deep sky objects (even the few seconds I'm currently limited to) I can get more detail than I can see. I get more detail on the Sun in hydrogen alpha light in photos but in "white light" it is the other way round. I can see more planetary detail than I can photograph and the Moon is about the same.

It all depends on what eyepieces and imaging equipment you have.