Why is my Mars not circular?

[Moonshed]

I have been busy practicing taking images of Mars with my new ZWO, flip mirror, and new software FireCapture and Autostakkert. 
After many trials and tribulations things are finally  beginning to come together and my images, although needing a huge improvement, are at last taking shape.

My one remaining problem, ignoring for now my need to learn how to process images properly, is that all my Mars images after stacking are not a regular shape, looking a little like the Moon a few days after full. 
After stacking  I first process in Registax 6.0 then move to PhotoShop.

This is the finished image.

Any help would as always be gratefully received.

Keith

 

 

[Waddensky]

The phase of Mars is currently around 95%. Could that be the reason?

[Nik271]

Hi Keith,

 

That's a decent image! Mars is now a month from opposition so it is developing a gibbous shape - just like the moon it has phases. This is perfectly normal.

[Moonshed]

41 minutes ago, Waddensky said:

The phase of Mars is currently around 95%. Could that be the reason?

Ahhhh... I knew all along of course, I was just pretending. 🤥

I have got so used to getting bad images this last couple of weeks I just naturally assumed it was me yet again!

Thanks, I am so relieved it isn’t me this time, first good news I’ve had since opposition.

[Moonshed]

43 minutes ago, Nik271 said:

Hi Keith,

 

That's a decent image! Mars is now a month from opposition so it is developing a gibbous shape - just like the moon it has phases. This is perfectly normal.

Thank goodness for that, I was beginning to think I would never get the hang of this!

A decent image? That’s a first 😄, thank you.