Spoke-type abberation

[huwbellamy]

Hi all, is it normal for my Nexstar SLT 102 to have a spoke like abberation when using high mag ie: 2x barlow and 6mm EP. The image is relatively clear but the spokey shadow lies over it. Turning the EP or barlow has no effect and I wondered if my objective was at fault?

Thanks, Huw.

PS: I don't use anything higher than 2x barlow plus 9mm since advised that 150x was max for my scope but I was curious about the pattern anyway.

[barkis]

Hi. Huw, You should not be getting anything like that in my opinion. You will need to introduce your other device one by one to see which one is the culprit. I would inspect everthing you use to make sure some foreign body is not being introduced to the light path. I doubt very much if your objective is defective. You will need to turn detective until you find the problem.

Good Luck Ron.

[huwbellamy]

Thanks Ron,

I have purchased a dielectric diagonal, upgraded barlow and EP's to try and eliminate what may be a more fundamental problem - I've only owned a telescope 1 month and I assumed it was a normal limitation of my scope. I have spoken to telescope house who agreed it didn't sound right and they will get back to me. I am wondering if they will exchange it for a different scope as there have been lots of niggles - the alt part of the mount was loose so the scope had a lot of slack, the battery compartment needs taping shut and the focuser mechanism and barrel were loose so I'm slowly losing confidence. I think I should have spent more on a better scope as I really enjoy this new hobby and there is a lot of choice in the "up to £500" bracket. Any advice well received as getting a bit confusd.

Huw.

[GazOC]

I'd return it, the scope isn't supposed to be a 'project' - it should work out of the box. As you say, £500 gives you some pretty good options.

[huwbellamy]

Indeed, any thoughts on celestron nexstar 5 SE SCT, Celestron 4 SE MCT, Meade ETX 105 PE MCT and Celestron C8 NGT Newt. All are Goto which I like from a track pont of view, I intend to look at a variety of solar system and deeper sky stuff. Not sure how I'd be about collimating things if it was frequently and I would like some level of portability, though I have had to fiddle a lot with the 102 anyway. Decisions, decisions.

Thanks, Huw.

[GazOC]

For views the 8" Newt will blow the other scopes out of the water, if you can store and handle one (they are quiet large) then I'd go for that. If thats not portable enough then the 5" SCT is a pretty compact setup but won't show anywhere near the detail the Newt will.

If you only 'need' the GOTO for tracking then you could save a bit of money by just getting motors rather than full GOTO.

Collimation is a 2 minute job once you know what you are doing, don't let it influence your choice of scope.

[Whippy]

I'd go along with that . But the I would 'cos I've got one!

Honestly, don't worry about collimation. It's a simple job once you've got the hang of it.

Tony..

[huwbellamy]

Thanks both,

Simon at Telescope Planet was very helpful and has agreed to exchange it. I like the idea of bigger aperture as my deeper space excursions have been enjoyable but decidedly dim. Will I get reasonable planetary views with a C8 and can I use a 2" eyepiece (nice 32mm Meade 5000 on order from FLO as I thought that would sort out my SLT)? I've even managed to convince my better half that I need to spend more on a scope - I am having a good day! Thanks again for the advice - it is difficult sometimes as a newbie, the learning curve is steep.

Huw.

[Whippy]

Huw, you'll be able to use both 2" and 1.25" EP's on the C8 as it has adapters for both. You will certainly notice the difference between your 4" and a C8! If I were you, I'd read up on setting up a german equatorial mount and polar alignment as initially, it can be quite confusing.

Tony..