Why can’t I get high magnification on the planets?

[Moonshed]

Over the last week I have been taking images of Mars, Jupiter and Saturn using an easy guider attached to my 200mm Celestron with my Cannon 1100D. The images have come out okay, just low power wide angle shots, the planets only appearing as small dots.

In the old days I used film camera and would put a 10mm Plossl  straight into the visual back of the scope and use a tele extender to give a high power so I could see the rings of Saturn and Jupiter’s GRS. 
However, this is this first time I have tried it with a digital camera and no matter what I do using the same set up I cannot get an image.

When I remove the camera and tele-extender I can see Mars in the centre of the eyepiece so I know I am finding it ok and tracking ok. I have tried adjusting the focus from end to end but still no image.

I cannot understand what I am doing wrong, any help would be greatly appreciated.
 

[Dave2292]

are you using a barlow and backyard eos planetary mode 5x zoom feature.

[PeterCPC]

Try using a flip mirror - it makes target acquisition so much easier. Also BYE as stated above.

Peter

[Moonshed]

4 hours ago, Dave2292 said:

are you using a barlow and backyard eos planetary mode 5x zoom feature.

No, I’m not using a Barlow, just a 10mm eyepiece and a tele-extender that gives eyepiece mag x 4.

I’m watching it on APT.

[Moonshed]

4 hours ago, PeterCPC said:

Try using a flip mirror - it makes target acquisition so much easier. Also BYE as stated above.

Peter

I’m not having a problem with target acquisition, my GOTO works great and my Telrad also confirms. It’s only when I switch to this high power I cannot get an image.

Are you saying backyard eos  is better than APT?

[Dave2292]

4 hours ago, Moonshed said:

No, I’m not using a Barlow, just a 10mm eyepiece and a tele-extender that gives eyepiece mag x 4.

I’m watching it on APT.

Not sure how apt works but with backyard eos you use planetary mode and then 5x zoom. Most people also use barlows instead 

[PeterCPC]

13 hours ago, Moonshed said:

I’m not having a problem with target acquisition, my GOTO works great and my Telrad also confirms. It’s only when I switch to this high power I cannot get an image.

Are you saying backyard eos  is better than APT?

You said "When I remove the camera and tele-extender I can see Mars in the centre of the eyepiece so I know I am finding it ok and tracking ok. I have tried adjusting the focus from end to end but still no image. " which suggests to me that you are not on the target with the camera. A flip mirror would help with this. I like BYE but it's a personal choice.

Peter

[Moonshed]

1 hour ago, PeterCPC said:

You said "When I remove the camera and tele-extender I can see Mars in the centre of the eyepiece so I know I am finding it ok and tracking ok. I have tried adjusting the focus from end to end but still no image. " which suggests to me that you are not on the target with the camera. A flip mirror would help with this. I like BYE but it's a personal choice.

Peter

Hi Peter,

I do not understand what you mean by a flip mirror, could you explain it for me please? Also I said that when I strip it back to just the eyepiece I can see Mars in the centre of it, so I do not understand what you mean when you say I am not on target.

Thanks

Keith

[Moonshed]

10 hours ago, Dave2292 said:

Not sure how apt works but with backyard eos you use planetary mode and then 5x zoom. Most people also use barlows instead 

Okay I will give eos a try and see how it goes although I have always found APT first class in all my imaging. Regarding Barlow lenses I sometimes use them for visual observing but cannot use them when using my camera.

[The Admiral]

I have no experience of doing this, but just a thought, if you use a much larger target like the Moon, you might be able to get a feel as to what the issue is, i.e. are you not achieving focus and/or whether your object centring is awry?

Ian

[Dave2292]

13 minutes ago, Moonshed said:

Okay I will give eos a try and see how it goes although I have always found APT first class in all my imaging. Regarding Barlow lenses I sometimes use them for visual observing but cannot use them when using my camera.

There probably is a planetary m

 

13 minutes ago, Moonshed said:

Okay I will give eos a try and see how it goes although I have always found APT first class in all my imaging. Regarding Barlow lenses I sometimes use them for visual observing but cannot use them when using my camera.

There probably is a planetary mode somewhere on APT I'm not sure? There are certain barlows that come with a t adaptor to attach to the t ring for the canon's. 

[PeterCPC]

1 hour ago, Moonshed said:

Hi Peter,

I do not understand what you mean by a flip mirror, could you explain it for me please? Also I said that when I strip it back to just the eyepiece I can see Mars in the centre of it, so I do not understand what you mean when you say I am not on target.

Thanks

Keith

This is a flip mirror https://www.firstlightoptics.com/diagonals/vixen-flip-mirror.html

The field of view when imaging is very small - you might be on target with the eyepiece but making the FOV smaller can easily mean that you are off target. I found that I searched for the target without a flip mirror even though it was there in the EP. With a flip mirror you can have the camera connected and the EP and you flip between the views to make sure the planet is absolutely centered. The only issue is that you have to collimate the flip mirror first but that's not too difficult.

Peter

[Cosmic Geoff]

The effective field of view when planetary imaging is quite small, and unless you use a flip mirror diagonal assembly (look it up) or centre the planet accurately in the eyepiece, you will have difficulty getting the planet image seen by the camera. 

In any case, a DSLR is not the best tool for planetary imaging. You really need a 'planetary camera' which is a specialised video camera, used in place of the eyepiece.  An ASI120MC-S would be a useful entry level camera for this. 

With my planetary cameras I have to switch between the full frame (for target acqusition) and a 320x240 pixel region of interest (for more efficient video capture).  The video is later processed into a sharpened image.

What is a flip mirror? see:

https://www.365astronomy.com/365Astronomy-Imaging-Flip-Mirror-with-Non-Rotating-Helical-Micro-Focuser.html

[Moonshed]

2 hours ago, PeterCPC said:

This is a flip mirror https://www.firstlightoptics.com/diagonals/vixen-flip-mirror.html

The field of view when imaging is very small - you might be on target with the eyepiece but making the FOV smaller can easily mean that you are off target. I found that I searched for the target without a flip mirror even though it was there in the EP. With a flip mirror you can have the camera connected and the EP and you flip between the views to make sure the planet is absolutely centered. The only issue is that you have to collimate the flip mirror first but that's not too difficult.

Peter

Thanks for the info, that looks like a good solution.

[Moonshed]

2 hours ago, Cosmic Geoff said:

The effective field of view when planetary imaging is quite small, and unless you use a flip mirror diagonal assembly (look it up) or centre the planet accurately in the eyepiece, you will have difficulty getting the planet image seen by the camera. 

In any case, a DSLR is not the best tool for planetary imaging. You really need a 'planetary camera' which is a specialised video camera, used in place of the eyepiece.  An ASI120MC-S would be a useful entry level camera for this. 

With my planetary cameras I have to switch between the full frame (for target acqusition) and a 320x240 pixel region of interest (for more efficient video capture).  The video is later processed into a sharpened image.

What is a flip mirror? see:

https://www.365astronomy.com/365Astronomy-Imaging-Flip-Mirror-with-Non-Rotating-Helical-Micro-Focuser.html

Thanks for the info. I do have a planetary camera, just a cheap £50 or so job that I use with Sharcap. I have used it on the moon but never tried it on the planets, I will give that a go, as soon as the weather improves!