Photography problem

[Ed Addis]

I have a Skywatcher 200mm reflector, and with a 3X Barlow and 10mm eyepiece, I can see Jupiter and moons pin sharp.  However, when I attach my camera (Panasonic Lumia G3) to the Barlow at prime focus, with no eyepiece, the image in the camera screen is much more blurred, no matter how I adjust the scope focus.  Exposures are even worse - just a blur with no discernible features.  Does anyone have any ideas as to why the exposures are so poor, given that the optical performance with the Barlow is very good?  Is this the result of some pre- or post-processing by the camera, and if so, how can I prevent this, and just capture what I see through the eyepiece?

Thanks

Ed

[christhebrit]

Do you click the release or is it a remote?

It may be due to vibrations, if so- you may want to try a time delay.

Chris

[Dr_Ju_ju]

Hi Ed,

when trying to focus, does it 'go through' i.e. in\out of focus from both ends, or does it not reach focus in either direction ??  

I suspect that the method you are using to attach your camera to the scope, does not have enough travel to achieve focus, therefore you must either lengthen or shorten the distance of the cameras focal plane to match that of the scope\eyepiece...

[Ed Addis]

It goes through focus, so I'm convinced that I'm getting the optics as focused as possible.  I'm using the release on the camera.  I'm not sure whether the shutter release on a system camera is entirely digital, or whether there's actually a mechanical shutter - if the latter, then I can understand that vibration could be a problem, but otherwise, I should think that with care it could be avoided.  I'm still wondering if the electronics in the camera are messing about with the image.  I had thought that turning off auto-focus would help, but it doesn't seem to have made any difference.

[D4N]

Have you removed the camera lens?

You can't use the cameras own lens for prime focus, it needs to be DSLR body > t ring > scope.

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[Ed Addis]

Yes - the camera goes straight onto the scope using a T-ring adaptor.  The only glass between the secondary mirror and the CCD is the Barlow.  It's not a DSLR, by the way - it's a system camera.  I think the clatter and vibration from the mirror in a DSLR would ruin any delicate focus setup.

[PeterCPC]

I think that Julian is correct here - reflectors can be problematic with digital camera to get focus. Some reflectors have shortened tubes for this very reason.

Peter

[D4N]

Try focusing on a distant object in the day (not the sun!). If you have a few mm of focuser travel left then you should be able to focus on stars.

If it is too bright cover some of the aperture up.

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[Shaddex]

I kinda have the same issue.  2x barlow with my 20mm or even with my 6.2mm gives nice detail but my DLSR takes rubbish images.

Im playing around with the ISO / Shutter speed on my Canon 350d but to no avail as yet.

With my camera at ISO100 and 200 with shutter from 1/20 to 1/500 Ive not gotten a decent image yet.

[christhebrit]

Using the release on the camera isn't easy.

Try putting it on a 10 second delay.

That will hopefully eliminate any vibration to the setup as you click the release.

 

If there is a remote release available for your camera, I'd recommend getting it.

Alternatively, perhaps invest in a different camera (DSLR/ CCD/ CMOS), these all have remote release options.

[Ed Addis]

Thanks for all the help.  Just to clarify:

Firstly, there is no question that I'm not reaching the correct focus - I can see the image go from massive blur, through the closest to focused and then out to massive blur again.  The problem is that at the best focus, the image in the camera screen, and in an exposure, is very much worse than as viewed with an eyepiece.

To all those who say they're having difficulty with a DSLR - these cameras work by interposing a mirror into the optical path between the lens and the CCD, which relects the image up into the viewfinder.  When the shutter release is actuated, the mirror swings rapidly up out of the way to allow the image to fall on the CCD.  This action can cause reactions in the camera stability, which can ruin delicate focus settings.  Not an issue for normal photography, but can be crucial for astronomy.  The camera I'm using is not a DSLR - it's a system camera, which has an electronic viewfinder, and so doesn't require that mirror arrangement.

Good idea to try a delayed sutter release - I'll give that a go next time.  I'd invest in the remote release, if I could convince myself that that's the problem, but so far I'm not convinced.  I still wonder if the camera is pre- and post-processing the image, maybe seeking a focus that it can't recognise.  Does anyone have any thoughts about that?

Thanks

Ed

[Ags]

To get a sharp image of Jupiter, you need to stack hundreds of frames shot with a high frame rate camera.

[D4N]

Indeed planetary imaging is normally accomplished by shooting video and stacking the frames together in software.

My DSLR doesn't have a mirror... At least not since I pulled it out

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[Ed Addis]

OK - thanks.  I'm aware of the stacking process, but please treat this as a very simple question.  Simply, how is it that the image I see in the camera screen is much more blurred and 'out-of-focus' than the image I can view through the eyepiece.  There isn't anything magic going on here, surely?  With 'normal' photography, I see the same thing in the camera screen as I do when I look at the subject.  I don't see an out of focus blurred version of it.  So why should it be so with astronomical subjects?

[wxsatuser]

If you can get focus I would assume it is seeing thats messing up your images.

The best planetary images are normally stacked from many frames of video.

Single frames will be very lucky to hit a clear spot.

[Ags]

The image I see in the eyepiece is blurred, at least to my eyes. I have to wait for the clear moments, and even then it is only clear for part of the Jupiter disc, and only for a moment.

[MattJenko]

Your eyes and brain are very good at teasing out detail and making a coherent image, much more so than a simple camera lens, which faithfully records only what lands on it. Fleeting moments of clarity in the atmosphere as mentioned are what people seek when doing planetary imaging, as a single frame simply will not be like the image the brain manages to do so extremely well. Not to say that there may not be something more fundamental at play, but I have found my viewing always sees more detail than unprocessed or liveview type images.

[christhebrit]

I don't believe your image is as blurred as you think- it's possibly overexposed.

Here are 2 examples for my trail of thought.

This first photo is what I took using my DSLR straight to my telescope, I used a remote release to eliminate vibration.

The exposure was a few seconds in order to ensure that I captures some thats and the 4 biggest moons.

As a result, the planet gave off so much light, that it isn't seen as sharp or focussed.

This second image was made with the DSLR connected to a 2.25x barlow and 8mm eyepiece.

I would need to take an image with a much longer exposure to get the moons and stars to show, but this was not my goal.

In short, I use my DLSR for DSO's mainly, but play around with bright objects.

Other cameras are better suited for planets if you want to achieve maximum detail, but you can get some detail.

I got this image of Venus the same way I imaged Jupiter, but the quality isn't too good.

For that reason, I'm looking into a QHY5L and ASI174MM.

Chris

[christhebrit]

*The exposure was a few seconds in order to ensure that I capture some stars and the 4 biggest moons.