Imaging problem

[John Whitehouse]

I seem to have developed a problem which I don’t understand which is becoming more regular as I approach my 79 th. birthday and I attach a recent image of Sirius as an example. 

My equipment:

Celestron 14” Edge HD, 0.7 Reducer, Off Axis Guider, CGX mount, ASIR AIR Plus, ZWO  ASI071MC Pro

any suggestion would be appreciated.

 

[The Lazy Astronomer]

Well, the good news is, it's not your eyes 🤣

I'm afraid I have nothing useful to offer, other than: collimation? 

[michael8554]

Hi John.

What are we looking at ?

Best focus, or an Airy disc ?

Do I see window frames, or roof eaves, in the image ?

So maybe an image of a lightbulb ?

But there are stars ? around the edges.

So maybe a damn good attempt at a Hubble-quality image of Sirius.

Just can't tell what's going on here.

Michael

[malc-c]

13 minutes ago, michael8554 said:

 

Do I see window frames, or roof eaves, in the image ?

 

Michael

Looks like a reflection of a dado rail, so I'm guessing the OP is observing through a window - and its that which is causing the deformed image 

[tomato]

Is this a photo of an image displayed on a monitor? If so it would be better to upload the image directly, as a .jpg file.

[Tomatobro]

That mottled effect dew maybe?

[John Whitehouse]

Thanks for your opinions but unfortunately I took this image of Sirius on an old IPad and duplicated it by photographing it off the screen.

When eventually the clouds disappear, I shall submit an accurate reproduction.

Many thanks for your interest and time.

[michael8554]

Meanwhile, post the original image you took with the iPad, not the duplicate.

Michael

[John Whitehouse]

Will do next week Michael and thanks for your interest.

[John Whitehouse]

This is a screenshot I took of the image which is Betelgeuse and I would be interested in any views as to what has caused this distortion.

[Elp]

Is your whole starfield flat? (Nice round stars across the whole fov), do you have an image with more than one star in view?

Edited May 8, 2023 by Elp

[John Whitehouse]

Thanks for interest already shown and I’m glad to report the problem was CHRONIC collimating which was established by purchasing ‘Bobs Knobs’ . The enclosed leaflet suggested an initial visual check through the front from a distance of 5-10 metres and it then became very obvious. I then took the decision to remove the secondary lens and the mis-alignment was very evident. I then used a micrometer and levelled it to +/- 0.02mm. Eureka