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Imaging with Barlow and eye piece


Paul Tomo

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The next time We have a clear night sky will be my first session into astrophotography and my first planetary object will be the planet Mars. The equipment I will be using will consist of the Skywatcher EQ6-R Pro mount, Skywatcher 200p, 2x Barlow lens and my new ZWO asi120mc camera. 
 

Would I be right in thinking that to take planetary and Luna images this is the only setup I’m needing too use, but if I want too take images of DSO’s I’ll need to require other equipment in order too do so.

 

I do have two Baader Hyperion eye pieces 17mm and 8mm, could I use these for astrophotography and if so what would be the best way of using these lenses and can they be used for both DSO’s and planetary use. 
 

Paul Tomo

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First question.

That is all the equipment you will need to do Planetary imaging.

To do DSO stuff you are going to have to go down the road of guiding, CCD cameras, processing which is one heck of a steep learning curve not to mention expensive.

You could try DSO imaging with the 120 MC but you will not have a lot of joy.

 

Second question 

As I have already tried to explain in your other post you will not be able to use your EP's unless you can find a way to hold your camera in an exact focal position above the EP.

Your 120 MC is roughly equivalent to an 8mm - 10mm EP in terms of magnification. 

 

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2 hours ago, Graham said:

First question.

That is all the equipment you will need to do Planetary imaging.

To do DSO stuff you are going to have to go down the road of guiding, CCD cameras, processing which is one heck of a steep learning curve not to mention expensive.

You could try DSO imaging with the 120 MC but you will not have a lot of joy.

 

Second question 

As I have already tried to explain in your other post you will not be able to use your EP's unless you can find a way to hold your camera in an exact focal position above the EP.

Your 120 MC is roughly equivalent to an 8mm - 10mm EP in terms of magnification. 

 

Thanks for the info Graham,


I now fully understand what you are saying about the EP. I do have another question for you, if tonight’s sky allows me to take some photos of Mars shall I let the mount and scope follow Mars or shall I let Mars travel across the view finder ? 
Thanks 

Paul 

 

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2 hours ago, Paul Tomo said:

Thanks for the info Graham,


I now fully understand what you are saying about the EP. I do have another question for you, if tonight’s sky allows me to take some photos of Mars shall I let the mount and scope follow Mars or shall I let Mars travel across the view finder ? 
Thanks 

Paul 

 

 

Paul

Centre Mars in the camera and run the mount on sidereal rate.

If your PA is good your mount will track Mars across the sky.

If you are using EQMOD you will be able to nudge the mount to keep Mars in the camera.

If you are using the handset you can nudge the mount by using the handset direction arrows.

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Further to that if you are going to be using the handset 

Set it to 2 times sidereal rate for nudging.

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Thanks Graham,

 

I had a go this evening at astrophotography but due to me not using the scope for a long time I had a bit of a night mare setting. Everything was going great until I got to the star alignment, not having wide eye piece was the main problem in finding the selected stars.

 

25mm is my widest eye piece I use for setting up and so buying a new wider eye piece is in order. The next problem was forgetting how to slew the mount when finding the selected star in star alignment. 

 

Once I eventually got setup and ready to start imaging the clouds moved in and put a stop to my Mars imaging session. 

 

Until next time....Paul 

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22 hours ago, Graham said:

First question.

That is all the equipment you will need to do Planetary imaging.

To do DSO stuff you are going to have to go down the road of guiding, CCD cameras, processing which is one heck of a steep learning curve not to mention expensive.

You could try DSO imaging with the 120 MC but you will not have a lot of joy.

 

Second question 

As I have already tried to explain in your other post you will not be able to use your EP's unless you can find a way to hold your camera in an exact focal position above the EP.

Your 120 MC is roughly equivalent to an 8mm - 10mm EP in terms of magnification. 

 

Are you saying that only the camera itself is roughly equivalent to an 8mm - 10mm EP

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On 12/01/2021 at 10:10, Paul Tomo said:

The next time We have a clear night sky will be my first session into astrophotography and my first planetary object will be the planet Mars. The equipment I will be using will consist of the Skywatcher EQ6-R Pro mount, Skywatcher 200p, 2x Barlow lens and my new ZWO asi120mc camera. 
 

Would I be right in thinking that to take planetary and Luna images this is the only setup I’m needing too use, but if I want too take images of DSO’s I’ll need to require other equipment in order too do so.

 

I do have two Baader Hyperion eye pieces 17mm and 8mm, could I use these for astrophotography and if so what would be the best way of using these lenses and can they be used for both DSO’s and planetary use. 
 

Paul Tomo

Many years ago (when I had a telescope!) I used to take pictures of the Moon using eyepiece projection.  In those days, most Barlow lenses were simply a single concave lens so eyepiece projection generally gave much better results.  I suspect that these days Barlows are much more refined so eyepiece projection is not so relevant, but any eyepiece is capable of effectively increasing the telescopes imaging focal length just as a Barlow lens is.  The maths are straight forward so for example, if you want to use your 17mm eyepiece as the equivalent of a 3x Barlow lens then you need to set the distance between the eyepiece (focal plane) and the camera sensor (focal plane) to 68mm (magnification plus 1, all times eyepiece focal length).  You will then need to adjust the focuser just under 6mm further way from the telescope tube than the normal visual focus position for that eyepiece in order to get the camera image in focus.  You can use any distance between the eyepiece (focal plane) and the camera sensor (focal plane) as long as it's at least twice the eyepiece focal length (otherwise you will not be magnifying the image!); you will just need to slightly adjust the focuser to suit.

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