Hello everyone,
Does anyone know anything about the 4.5" Newtonian reflectors sold by Dick Smith for just under $200? See
http://www.dse.com.au, and search for "114 telescope". I've had some great viewing sessions (best one on xmas night, out of town), and marvelled at the usual things first timers marvel at: moon, Saturn's rings, Jupiter's moons, few of the brighter open clusters and even the gas clouds in M42.
While I've enjoyed all that, I'm not all that happy with the scope. I'm hoping you people might be able to help me fix it up a little or tell me to stop wasting my time trying to do impossible things.
First thing was the mount. Very wobbly, but still better than some of the ones I've seen in camera shops (on scopes costing heaps more). In a gentle breeze 30x is the highest useful magnification. I built a dob mount for it and that's much sturdier. I miss the turn of the knob tracking the sky though.
The other thing is the optics. It came with 30, 10 and 6mm EPs (and two barlows that are not compatible with any of the EPs with the focuser!). The view with the 30mm EP (30x) looks fairly clear, but at any higher magnification I can't get a sharp focus. Stars are definitely not pinpoints, but kind of blurry three pronged blobs (diffraction pattern from the spider I presume). Saturn & its rings look more like an ellipse with two holes in it than two distinct objects.
A guy in a scope shop said the EPs are nothing special but they're OK and that even with a basic 4.5" reflector I should get clear & crisp views and be able to see the Cassini division, the shadow of the Saturn on the its ring and stars as points of light. Another shop did a quick adjustment of the main mirror with a laser collimator.
I had the scope out since but the view has not improved noticably. I tried the "star test" but I don't see anything that even resembles those theoretical diffraction patterns that I'm supposed to see.
So, after that bit of frustration, I made a laser collimator out of a cheap keyring laser and some plumbing bits, but it's hard to get good quality 1.25" pipe, so it's pretty rough. No improvement.
Despite the poor performance I've enjoyed the scope (or should I say the sky) enough to want more, and have ordered an 8" Dob from Andrews Communications in Sydney (I'm in Melbourne).
If possible I'd still like to fix up the 4.5", since it'd make a nice companion scope for its bigger brother, being so much lighter, smaller, and hence portable and accessible for the little people.
Any advice, secrets of the trade I'd very much appreciate.
Cheers,