Bloated stars

[Landy Dave]

I have been slowly getting into imaging and I have notice my stars are pretty bloated. Here is a 100% crop from the centre of 240 second exposure at ISO 400:

I am using a Canon Eos 70D with an Astronomik CLS clip filter through a Skywatcher 102T.

Is this because I am using a cheap scope?

My plan is to buy a ED80 when a second hand one comes up or I save enough for a new one

[wxsatuser]

Could be, looks like chromatic abberation.

[reddoss]

The ED80 will be a much better scope for imaging,

You may also need a 0.85 reducer/flattener to bring the f/ratio down from f7.5 to f6.37 which will make it much easier to image with shorter sub-frames.

Star bloating tends to occur much more with DSLRs than with CCDs.

[ronin]

Certainly looks like chromatic aberration.

Another problem or feature that is often missed is that thje scope will have a "large" depth of focus. Makes it easy to get or find a reasonable focus when viewing but means there is not really a sharp well defined focal plane, so things are a bit bloated.

Still enjoy the imaging, the experience will be worth it when better equipment is acquired.