Why are my images partially blurry and how to stop this

[jamesj01]

Hi everyone,

I am new to astrophotography and of course started by taking a photo of the moon (as attached) using my Canon EOS500D camera - 1/250 exposure time, 800ISO. I used my celestron 127EQ telescope with a adapter for the camera of course. I used no eyepiece. 

However, i find that it is slightly blurred, and upon taking pictures of nearby stars, i also found them to be blurred, even with a high exposure time. am i doing anything wrong at all or is this simply because of my setup? 

Many thanks

IMG_3243.CR2

[MarkAR]

I think your focus looks off. If you're having trouble then I would suggest trying a Bahtinov mask.

[alacant]

10 hours ago, jamesj01 said:

i also found them to be blurred

Hi 

JTOL. What @MarkAR says and...

Is the telescope OK visually? Is it collimated? Do you have a long lens you could test against?

How do you take the shot? Maybe try without touching the camera. At long focal lengths, even at 1/250s, there will be two images recorded. An image -corresponding to a shutter release- and a second when the camera has settled.

The atmosphere also has to be still. For the moon, probably better to take a video and stack the best frames.

HTH

Edited June 2, 2020 by alacant

[Cornelius Varley]

@jamesj01 Can you upload the image as a jpeg or png file ? This way the image can be viewed without having to downloaded and can also be viewed on all platforms.

[alacant]

.cr2 -> .jpg

HTH

Edited June 2, 2020 by alacant

[jamesj01]

@alacant thanks for the speedy reply - my telescope uses a newtonian reflector and i dont know if it is collimated or not sorry. 

When i look through the eyepiece without a DSLR attached, it is clear as daylight and the detail is amazing for both stars and the moon. It is blurry however through my camera. I strongly go with what you said about my telescope moving when i take my picture so i have purchased a remote. I have heard they are essential. So possibly there is to much movement when i press the shutter button?

Many thanks

[jamesj01]

@MarkAR i will look into that - are they used primarily if you wanted to photograph an object in the sky?

[Chefgage]

5 minutes ago, jamesj01 said:

@alacant thanks for the speedy reply - my telescope uses a newtonian reflector and i dont know if it is collimated or not sorry. 

When i look through the eyepiece without a DSLR attached, it is clear as daylight and the detail is amazing for both stars and the moon. It is blurry however through my camera. I strongly go with what you said about my telescope moving when i take my picture so i have purchased a remote. I have heard they are essential. So possibly there is to much movement when i press the shutter button?

Many thanks

When you look through the eyepiece the moon and stars look clear/sharp. This tells us the focus is ok for that eyepiece. When you then connect your camera how are you focusing the camera? Are you using the live view and then zooming in the get better focus?

Edited June 2, 2020 by Chefgage

[jamesj01]

Just now, Chefgage said:

When you look through the eyepiece the moon and stars look clear/sharp. This tells us the focus is ok. When you then connect your camera how are you focusing it? Are you using the live view and then zooming in the get better focus?

Yes, when i connect my camera it is in manual mode and i am using the focus knobs on the telescope to achieve the cameras focus

[Chefgage]

1 minute ago, jamesj01 said:

Yes, when i connect my camera it is in manual mode and i am using the focus knobs on the telescope to achieve the cameras focus

Do you then re-focus using the X5 zoom and then again using the X10 zoom in the live view?

[jamesj01]

1 minute ago, Chefgage said:

Do you then re-focus using the X5 zoom and then again using the X10 zoom in the live view?

sorry juts to clarify, the X5 and X10 zoom are the buttons on the camera correct?

[Chefgage]

5 minutes ago, jamesj01 said:

sorry juts to clarify, the X5 and X10 zoom are the buttons on the camera correct?

Yes that's correct. How I focus my camera is to centre a star in the live view screen. I then set the focus by focusing back on forth looking at where the 'sweet spot' is. I then leave the focus on this sweet spot. I then zoom in to X5 on the camera and then repeat the process. Then zoom in X10 and again repeat. You will find at x10 that you only need a very tiny movement of the focuser to change focus.

This process helps dial in the focus so that stars appear sharp.

[jamesj01]

8 minutes ago, Chefgage said:

Yes that's correct. How I focus my camera is to centre a star in the live view screen. I then set the focus by focusing back on forth looking at where the 'sweet spot' is. I then leave the focus on this sweet spot. I then zoom in to X5 on the camera and then repeat the process. Then zoom in X10 and again repeat. You will find at x10 that you only need a very tiny movement of the focuser to change focus.

This process helps dial in the focus so that stars appear sharp.

thats brilliant - thank you will try this tonight  

[jamesj01]

@Chefgage how do you focus for the moon - do you follow the same process?

[Chefgage]

I would do yes. Although I find focusing on the moon easier as you can see surface details which makes it easier to focus as apposed to a point of light like a star.