ED72 DS-Pro First Light - Weird circular spots on image

[tutting]

Hi All,
       As the title says, I've just used my new ED72 DS-Pro paired with the OVL flattener and my Nikon D5300 to take some images of M45 and noticed some weird circular patches. The stars inside the patches seem to be fine so I don't think it's dust. Looking through the OTA I don't see anything on the glass and the OVL looks ok too. I should point out I do not have this issue when using my normal DSLR lenses. Does the ED72 have a coating on the glass, is it something to do with that maybe?
Any help greatly appreciated at this is my first time using an OTA (been using camera lenses up to now)

Thanks in advance
   'tutting'

[Snoani]

Hi Tutting

To be honest, to me it does look like dust or artefacts within your image train.  Did you take any flat frames for this image as this would confirm whether it is or not?

Jem

 

[tutting]

1 minute ago, Snoani said:

Hi Tutting

To be honest, to me it does look like dust or artefacts within your image train.  Did you take any flat frames for this image as this would confirm whether it is or not?

Jem

 

Thanks for your reply Jem, unfortunately I didn't take flats on this occasion it was far too late and I ran out of time. I am imaging at the moment and will try to take some as I finish....

[Adam J]

41 minutes ago, tutting said:

Hi All,
       As the title says, I've just used my new ED72 DS-Pro paired with the OVL flattener and my Nikon D5300 to take some images of M45 and noticed some weird circular patches. The stars inside the patches seem to be fine so I don't think it's dust. Looking through the OTA I don't see anything on the glass and the OVL looks ok too. I should point out I do not have this issue when using my normal DSLR lenses. Does the ED72 have a coating on the glass, is it something to do with that maybe?
Any help greatly appreciated at this is my first time using an OTA (been using camera lenses up to now)

Thanks in advance
   'tutting'

It's dust close to the camera, probably inside the DSLR on the front filter. 

[900SL]

Dust on the flattener or sensor

I use a puffer on my flattener and sensor before any session. I also run the Nikon 'clean sensor' menu option.

And flats. I've found out the hard way that telescope assemblies are more prone to dust artifacts than prime lenses

[tutting]

On 02/11/2021 at 23:09, Adam J said:

It's dust close to the camera, probably inside the DSLR on the front filter. 

Many thanks, i'll take a look

[tutting]

On 03/11/2021 at 03:40, 900SL said:

Dust on the flattener or sensor

I use a puffer on my flattener and sensor before any session. I also run the Nikon 'clean sensor' menu option.

And flats. I've found out the hard way that telescope assemblies are more prone to dust artifacts than prime lenses

Thank you