Telescopes and Telescopes

[PSALM19.1 (Shaun)]

Wow. Walked in to Stockland Shellharbour last night and noticed an Australian Geographic store had opened up...sells Celestron Scopes...got me thinking: if you lined up an 8" Dob, a Nexstar 130SLT, a Nexstar 4S and an Astromaster and you looked at Jupiter on a splendid night, which one would be the winner??? (Rules: none, except that we are LOOKING not photographing with a thousand dollar camera and high tech astrophotography programs and software!)

[cometcatcher (Kevin)]

The 8" dob. There's a physical relationship between objective diameter and resolution.

[Shark Bait (Stu)]

Originally Posted by cometcatcher

The 8" dob. There's a physical relationship between objective diameter and resolution.

+1 for the 8" Dob

Australian Geographic has it place in the market and it is fun to have a have a look at what is on offer but it is a pity they overcharge for their astronomical gear. Really aimed at first time buyers.

[glend (Glen)]

+1 for the 8" dob but suggest you buy it from Andrews Comms, or Bintel. For visual use aperture is king. Just compare the resolving power and limiting magnitude of all those scopes you listed, I am postive the 8" dob will come out on top.

Or you could buy my 12" dob which is for sale in the IIS classifieds and on ebay.

[barx1963 (Malcolm)]

Not even a contest, 8" dob!

Malcolm

[astronut (John)]

More aperture, the better.

[Wavytone]

8" dob, easily.

[PSALM19.1 (Shaun)]

I thought so! When I was deciding which scope to buy a few months back, I seemed set on the Nexstar 130SLT, but was glad to be pointed in the direction of an 8" dob! They just make those Nexstars look inviting in the shop and in their on-line promos! I wonder what an 8" Nexstar would be like though....

[doppler (Rick)]

The 8" dob would still be brighter on DSO's. The dob has a faster f ratio and the only glass you look through is the eye piece. The computer guiding would be the big difference with the nexstar though.

[astronobob (Bob)]

General 'Rule of thumb', 50x magnification per inch of aperture
More aperture = More light = more magnification for planets etc

In saying this, a different rule of thumb for faint galaxies & faint nebulae, still more aperture is always better, though lower magnifications will see fainter targets, eg galaxies & Nebulae, better and crispier then higher magnifications

Comparing 8" to 8" in different newtonian scopes, an 8" F4 is much better suited for faint galaxies and nebs & will perform poorly with planets ; where as an 8" F10 is much better for moon and planets but will perform poorly with faint galaxies and nebs.

Ultimately, $$$ will restrict all of us when it comes down to Aperture, Optic quality, Reflectivity Coatings, Configuration designs and Polishing accuracy, and of course the mount to carry them

[ManUtdFans (Alan)]

Originally Posted by glend

+1 for the 8" dob but suggest you buy it from Andrews Comms, or Bintel. For visual use aperture is king. Just compare the resolving power and limiting magnitude of all those scopes you listed, I am postive the 8" dob will come out on top.

Andrews looks increasing their 8" dob again and again.
It was $429 I think last month (or Oct I can't exactly remember), then last month up to $449 (free delivery) and now $479.

[noeyedeer (Matt)]

when I was looking at the gso 8" dob, their prices went from being $200 difference between the 8" and 10" to when I had the money there was $50 difference, so I got the 10" instead.

was a no brainer. I had to double check that the price was right for the 10" when ordering. the next day they put up the price on the 10" so I was lucky.

I'm assuming when they get a shipment in they lower prices, and as stock runs out they increase. at the time the Aussie dollar was above the USD so it didn't make sence for the price hikes. only supply and demand made it seem more realistic.

matt