Skywatcher startravel range......(a few Questions)

[stan26]

Hi there,

Just wondering, beings I now have a SW EQ3-2 mount on its way to me and I'm in need of a scope to go with it for gerneral purpose observation and a bit of wide field/DSO photography, and also im restricted to a tight budget of around £150 (for OTA), What results could I expect from a Startravel, say maybe a 102, or 120 at a push?? I know "CA" WILL be a problem, but for a newb just starting out surely I'm likely to get some pleasing results??? I'm just thinking the EQ3 would handle this size scope quite nicely....

Are there any problems with fixing/focusing my Canon 500D dslr to these scopes? any other bit's im likely to need i.e extension tubes etc??

Can I change the FOV with mounting my dslr to this type of scope, Or does it effectivley become a fixed focal length prime lens..?

Finaly "fringe killer filters" are these affective?

Sorry for all the questions

Thanks

Stan.

[stan26]

Oh yeah forgot to add, I'm am constantly on the look out for an ED refractor to come up 2nd hand! Pitty I can't view the sales section on here yet.........

[John]

The Startravels are fine scopes for low to medium power observing but are not so good for high power viewing. The CA will increase with aperture - how much it bothers you is a personal thing though.

The finge killers do reduce the CA but often introduce a tinge to the image of their own in return. They can't work miracles though - an F/5 achromat will have it's limits.

The option of a low cost ED80 is attractive and your budget will nearly go that far - a nice Celestron ED80 was on e.bay for £175 "buy it now" a few days ago so they do come up. The UK Astro Buy & Sell web site is also worth watching until you can access the SGL buy & sell sections.

As you have an EQ3-2 you might want to consider a used 4" F/10 achromat. The TAL100's come up at around your budget and are excellent - shey show much less CA than the Startravels do.

[jgs001]

I have an ST80 clone. I've used it for Astrophotography. You will need at least a 30mm extension of some sort between the focuser drawtube and the camera, a T ring and an appropriate push fit barrel for the scope (my clone is 1.25"). I used a Baader Semi APO filter to help reduce the CA yet maintain a more natural colour. It worked, quite well.

http://stargazerslounge.com/equipment-reviews/67599-baader-ca-filter-comparison.html?highlight=filter

might help some.

[stan26]

Thanks guys.

How would an f10 refractor cope with dso's , I.e M42? surely its to big a focal length and to narrow FOV? I would love a long frac for lunar/planet work though.

What about a mak? Do they suffer from much CA?

Thanks.

[John]

With 2" accessories an 4" F/10 can show nearly 3 degrees of sky - enough to get the whole of the sword of Orion into the field of view.

Mak's don't suffer from CA but their FoV is even narrower than slow refractors as they tend to have focal ratios or F/12 or more. The smaller ones are not suitable for 2" accesories either.

[stan26]

Thankyou guys.

Had a chat with FLO today. I think the ST102 is my first choice if I buy new. I like the idea of the 2" focuser Compared to the st80. I think this scope will suit my requirements.

Will def look out for ED glass though.

Stan.