Starry looking stars

[Blackrose]

Hello astrofirends,

I have a TS APO 72/432 Telescope and after I used it for the first light, my stars look like the stars kids draw. A hexagonal halo, especially around bigger stars. Is this normal or am I doing something wrong? I use the 1x flattener and an IDAS V4 mounted in front of the flattener. Thanks in advance,

 

CS

Kami

DSC_6696.NEF

[alacant]

1 hour ago, Blackrose said:

A hexagonal halo, especially around bigger stars

Hi

OK. This should be easy. Need to try the same fov with:

- telescope only

- telescope + flattener

- telescope + filter

If it were a reflector, I'd say you'd missed focus but...

I think you're seeing the hexagon because of diffraction spikes.

Cheers and HTH.

[DaveS]

Have a look into the objective. Do you see three little spacers intruding into the light path? Three spacers will give you six diffraction spikes as you've noted. It may only be a tiny bit but it can be enough.

[Blackrose]

20 hours ago, DaveS said:

Have a look into the objective. Do you see three little spacers intruding into the light path? Three spacers will give you six diffraction spikes as you've noted. It may only be a tiny bit but it can be enough.

Everything seems pretty round and symmetrical to me. Is this possible because I couldn't find the correct backfocus? I am using a DSLR with the flattner, so it should be automatically in working distance from sensor as the company claims. I use the 72 1x flattener from TS.

[DaveS]

What I'm seeing has all the hallmarks of diffraction, which suggests that *somewhere* in your light path you have three (Or possibly six) edges intruding. From the photo above the OG looks to be clear of edges. the diffraction isn't huge, which means you're likely to be looking for odd lens spacers, possibly in the reducer.

It's unlikely to be a camera spacing issue as that would show up as elongated stars in the corners, and they look pretty round to me.