Scope For Double Stars Please...

[Coco]

Hi

I have a 12" Revelation dob which gives very pleasing images, I cannot fault it to be honest it has no optical issues whatsoever for me and deep sky views are superb.

My question is I cannot resist the potential purchase of a 6" F8 DOB for planets etc, my garage is already cluttered with 12" Dob, Skytee II on Eq6 tripod with Skywatcher pillar, motorcycles, push bikes, and summer outdoors furniture.....

Double stars show good colour in the 12" Rev but set up and cool down not always handy, I'm  wondering if anyone could jump in with suggestions?

Double stars being the/my main focus here, budget 500 quid!

Cheers 
Guy  

[Mr Spock]

Perhaps a 4" apo? Harrisons do the Altair 102ED for £495 though I believe they are out of stock. There's one used in the buy/sell section here too.

While an 8" Dob might be a good idea they still have more cool down time and take up floor space. 

[NGC 1502]

Hello Guy.

Sounds like you’re mostly happy with the 12” Dob, apart from setting it up and cooldown. Please don’t forget that more aperture equals greater resolution for planets and double stars.

You mention the 12” is kept in the garage, so assuming no heating in there that will help with cooldown. Does it have a cooling fan for the primary and do you use it?   How about lockable castors on the Dob base, that would help with moving it to your observing place.

Ed.

[M40]

There is a skymax180 for sale on the site for just above your budget, a fantastic telescope for double stars. I keep mine in the garage and never been concerned with cool down times. By the time I have it all set up, it's good to go. All the best

[John]

There is an Intes 6 inch F/12 mak-cassegrain in the classifieds for your budget. Nice double star scope I would think 👍

(I've nothing to do with the sale I ought to add)

[RobertI]

I don’t know if @Coco has made a decision yet, but I’ll add my thoughts. Refractors do give perfect star shapes and beautiful airy discs so in theory perfect for doubles, but they are limited by aperture (for most of us) which creates another problem, at least for me with my 4” refractor - when I get to really high powers for those tight doubles, the stars look like discs rather than … well …. stars! The smaller the aperture the bigger the ‘disc’ appearance.  I have found that my 6” reflector does not exhibit this effect. I know it’s just an aesthetic thing, and I don’t recall ever seeing anyone else complain about it on SGL, so it’s probably just me! But I think for a doubles-only scope I would go bigger than 4”, and I think a 150mm or 180mm Mak would perform very well. 

[mikeDnight]

I don't know the owner of this beauty and I hope he doesn't mind me using this pic, but this is what you need for deep double stars. Far better than those reflector thingies! 😉 You just cant beat a refractor for perfect star images!  Seriously though, it would take a very long time before you bottomed a double star list in the 4" to 5" aperture range.

 

[dweller25]

Well that’s a scope and a half, owner looks like Fernando Alonso of Formula 1 fame  - which makes sense as you would need plenty of dosh to buy that 🤣

Edited November 9, 2023 by dweller25

[lunator]

I've looked at a lot of doubles through a variety of scopes from small refractors like the ETX70/ST80 Upto my 8"reflector and 250mm OMC.

They have all given me good views of doubles. 

Generally I can see doubles down to about 1~1.5" on a decent but not perfect night. This equates to an aperture of around 120mm..

I do own an ST120 which on paper is ideal but as it is an F5 the colours can be a little strange.

It does come down to the age old question what telescope would get the most use...

I guess you need to decide what most important out of resolution, portability or purity of the image.

Cheers

Ian

[Louis D]

52 minutes ago, dweller25 said:

Well that’s a scope and a half, owner looks like Fernando Alonso of Formula 1 fame  - which makes sense as you would need plenty of dosh to buy that 🤣

Here's the CN thread it originated from.  The fellow is named Francesco with CN handle Francesco_Italy.  The pictured scope is a 220mm f/15 with a Chromacor-II N in the optical train for chromatism correction.

[Peter Drew]

I have a 220mm F12.5 refractor, I don't think I've had a look at a double star yet!    🙂

[F15Rules]

On 07/11/2023 at 21:43, John said:

There is an Intes 6 inch F/12 mak-cassegrain in the classifieds for your budget. Nice double star scope I would think 👍

(I've nothing to do with the sale I ought to add)

Guy, John is correct..the Intes MK67 F12 Mak is a superb double star scope. I have owned 3 150mm Maks in the past, including an MK67, and all were excellent: compact, solid, easy to mount, and with great Optics. I now have a Tak FS128 but the MK67, once cooled ( and with a Sitall glass mirror it cools quickly), would give the Tak a real run for it's  money.

And the one for sale on SGL, is right on your budget at £500! ( I have no connection with that sale..😊).

Below are 2 pics of previously owned Ylena 150mm F14 Mak, made by Lomo. This scope was very similar in size to the MK67 being sold on SGL. And very happily  mounted on an EQ5 class mount (a Vixen GP would be perfect!).

Hope that helps!

Dave

Edited November 9, 2023 by F15Rules
Photos added

[The60mmKid]

I think the humble 6" f/8 dob is a great idea. It's already mounted, it's so easy to move around, it cools quickly, it has a small central obstruction, and f/8 mirrors are usually high quality since they are easy to make.