Specific telescope for double star observation.

[pluton]

Hello,

I am looking for a telescope specifically for visual observation of stars doubles.

For CP and I have a Dobson telescope, which I do not like the image that provides for double stars, very unstable and not very clean, that is why they wanted to consult on this issue.

I read that refractors have an advantage over the spotlight on this issue .. image more stable, cleaner, ...

thank you very much

[Mr Onions]

What's your budget and size limitations?

[Bender]

Neil English seem to love his Skylight 4" f15 for his passion of double star observation, according to his book about refractors.

[barkis]

The refractor is the instrument of choice for Double star work.

Even my 150mm f8 Achromatic frac. does a good job for me.

The long focal length 4" f15 will be better.

Apochromatic refractors are preferable, especially if cost is not a consideration.

Ron.

[SiriusB]

Aesthetically i find refractors the most pleasing for double stars.

For the same cash as a 4" refractor you could split tighter doubles with a larger alternative optical design.

A long focus newt should work well,& you could use an "undersized" secondary for this work.

Maybe look at a mak also?

I'm sure i read somewhere that obstructed optical systems have some advantage in splitting tight doubles, not sure i followed the theory though.

[Merlin66]

The easiest and most satisfying double scope would be a refractor >f10 with an ortho eyepiece.

[Caldwell 14]

TAL 100RS?

[Caldwell 14]

...er that would be at the budget end of the market

[cathalferris]

As refractors have better-looking Airy disks with dimmer first-order rings, they tend to give a 'cleaner' view of double stars than ordinary reflectors, with a slightly easier guage on whether a double is double or not (peanut shaped etc).

There's no doubt that a long-focus well designed and well constructed Newt can give near-equal views, it's hard to beat the simplicity of the well-built long F/ratio refractor.

Add to this the fact that refractors tend to be higher off the ground and away from an observer's plume of warm air may be factors in steadier views.

[MjrTom]

My vote would be for something like a Tal 100RS

Also not a huge investment if you later decide you prefered the views from a newt, not that I expect you will

[canuck]

Apochromatic refractors are preferable, especially if cost is not a consideration.

Ron.

Well, not really...the wide field and colour control advantages of apochromats do not really offer any particular advantage in the area of double stars. The image stability of a long focal length instrument like the TAL 100RS makes it an excellent option, or something like a Vixen 80 or 100mm achromat refractor would do the job very well. Both available at a very reasonable price...

[Nexus 6]

Will have to check out that Tal again Caldwell and soon! Must admit I have become a fan of doubles myself recently.

A small frac alongside to compare with would be handy too.

[Merlin66]

99% of all double stars discovered, observed and measured up until the 1950's (well if you exclude Willie Herschel) were done with achromats......

[Damo636]

Not sure of your budget but the Lyra Optic 102mm f11 is excellent at splitting doubles. Its roughly £100 more than the Tal 100 RS but literally "light years" ahead on build quality.

Lyra Optic - Telescopes/Accessories

[philj]

Long focus achromats excell at double stars. The stability of the image and the ability to use longer focal length eps for higher mags make an excellent tool for the job.

I have a 4" F15 and an 80mm F15, both are spot on star splitters

Also take it from an experienced achromat observer, forget all the rumours and horror stories from the shorty apo camp:D about colour in achromats when looking through a quality F15 achro

Philj

[estwing]

i heard that telementor's are good for this...so what's my first port-of-call?

[Caldwell 14]

Will have to check out that Tal again Caldwell and soon! Must admit I have become a fan of doubles myself recently.

A small frac alongside to compare with would be handy too.

My 8mm BST seems to do the buisness for me Alan, check it out.

[Merlin66]

The largest aperture f10+ achromat you can buy within your budget.

[philj]

Seconded with Merlin

[MjrTom]

Not sure where you are in the country but there is a Tal 100RS on eBay at present

eBay - The UK's Online Marketplace

bear in mind that eBay prices are suffering stargazing live effect at the moment and seemingly reasonably priced items are selling for more than retail

Worth keeping an eye on it if it stays below £200