Poor quality EP or seeing conditions?

[patomlin76]

Hi, wondered if anyone could help with this query...

I was out just now having a look at Venus before it set, and when I was viewing at higher magnifications with my 10mm stock eyepiece and then with a 3x barlow lens, I could see the shape but right from the centre of the bright spot I had a four-point starburst.

I believe the scope is collimated to a satisfactory degree - out of focus is a very concentric circle (with a slight notch top left which I'm not sure about)...

I know the Skywatcher 10mm EP is not the best out there, so is this just the effect of a poor eyepiece being used in conjunction with a (quite decent) 3x barlow?

Cheers!

Paul

[RikM]

It is the diffraction pattern from the spider vanes holding the secondary mirror and is quite normal for a Newtonian looking at a bright object.

[Mr Spock]

The 10mm eyepiece isn't very good and the Antares Barlow isn't that good either. On top of that x195 for a 130mm is pushing it a bit.

[patomlin76]

Thanks for the replies. At least I know what I am experiencing is par for the course on a Newtonian...

Regarding eyepieces though Mr Spock, out of the 10mm EP OR the Antares Barlow, which is the greater of the two evils? The barlow cost me £35 (so not as cheap as the unbranded ebay ones, but granted, could cost more).

I'm looking at upgrading the eyepieces sometime soon when I've had a chance to get to grips with the scope (and just like lenses on a DSLR they can always be kept...).

To be honest though, even at x195 mag the scope still fulfils my needs, I just think I'd get better quality views out of the same scope with better EPs... correct?

Cheers

[RikM]

Better lenses can give you more contrast or a larger field of view at the same magnification or longer eyerelief so they are more comfortable to use. Really good ones will show a slightly brighter image with better colour and so a bit more detail can be teased out. But they won't show you anything you can't see with the kit EP's.

The BST explorer range from Sky's the limit get good reviews. I find it is better to stick to a reasonable magnification rather than push it too far. I prefer a smaller but sharper image better than a big dim mushy one. I seldom use more than 170x in 10" or 150x in my 6" but I am not really a planetary enthusiast.

[newman]

As a very first measure I'd look to replace the stock 10&25 most SW scopes come bundled with these days - the 10mm is the worse offender here so you might want to look at replacing that one first.

But, I'd also get rid of the 3x barlow in your shoes. A 2x would see a lot more use in that scope.. a good 2x, that is.

[damnut]

Hi There,

The theoretical max magnification for your scope is 260x, you are pushing the limits on a poor eyepiece. I have a 10" sct theoretical limit 500x but very rarely use more than half of that as seeing is not great.

Echo the comments about the BST explorers they are great ep's for the cost and Alan is a nice chap to do business with too!.

Good luck with your choice.