is this due to poor seeing conditions? (new scope)

[mr saddo]

Hi all. just been out this morning cold and frosty, had my new scope out, its a sky watcher evostar 120 refracter 1000mm focal length, got on to Saturn but..hard to get a really sharp image, in and out of focus, mars was flaring slightly on one edge, could not get a pin point star also flaring, is this due to cold air frost -1 this morning, or is my scope faulty, it is second hand mind you. see picture below, i know the mount is not suitable!!

Stargazers Lounge - mr saddo's Album: skywatcher evostar 120 refracter

[steppenwolf]

I think the mount *may* be contributing to this as a sturdy mount with a 1000mm focal length is vital. The flaring is a little more worrying as this could be a collimation error but unlikely in a refractor unless it has been 'got at' by the previous owner. In an out of focus could simply have been the 'seeing' conditions as poor seeing can make planetary observations horrendous.

[mr saddo]

hi there, i have checked all the screws they look ok not chewed up by a screw driver etc the scope is in excellent condition, i will go out on a dark night and try again, the weather was frosty here in uk this morning. if ok i will spend money on a decent mount if not it will go back.

[mr saddo]

Hi, been on phone to people i bought it off, i asked them if it had been checked before sold, has this is second hand, he said the bloke who traded it in bought it off them in first place, he said the optics had been checked, i will have another go when the sky is dark with no frost!. maybe iam flapping about nothing, but bad seeing condition.

[John]

You can check the collimation of a refractor using a simple cheshire eyepice. I use this method:

Refractor Collimation

If you don't have a cheshire eyepiece the star test should be a good indication, as long as the scope is cooled.

You really do need a better mount for it !.

[mr saddo]

hi there, thanks for that, i have a cheshire, i will have a look at the scope tomorrow, i have star tested tonight and there is a bit of flaring on stars, they wont pin point. yours paul.

[Moonshane]

could it be that the scope needed to cool down? a decent sized refractor like this will (contrary to popular belief) benefit from cooling down, well, mine did, especially when going from warm house to -1c.

the other option is that it was chromatic aberration which would be normal and one of the 'features' of this sort of scope. was the flaring coloured? (e.g. blue or purple)

what magnification were you using?

[mr saddo]

old post of mine i have found, ile add on, it ws a bit flaring on a 15mm ep, i did check the collimation has suggested by someone to shine a bright light in to the cheshire 45 face wjndow, and i should see 2 discs over lapping the more the better, they where, so it was in collimation. i sent the scope back anyway i was not happy, the were very good Astronomia/ telescope outlet,and gave me my money back.