Which scope is best for doubles

[Dave In Vermont]

I've never seen one. But I'd love one as well! Not too many old Russian tanks around the US though.

Pity,

Dave

[leo82]

How long does the mak take to cool down? It’s the one thing that’s really holding me back.

With this in mind and if it’s most likely really 119mm would I be better with a 120mm evostar? I guess it would be a matter of length. 

 

[JG777]

The one I had usually took about 40 minutes to cooldown, sometimes a bit less sometimes a bit more, hard to be exact as it depends on conditions. 

[leo82]

Hmmm I do like the idea of putting it on the mini dob base but not really being able to grab at a moments notice when there’s a gap in the clouds could bug me. I know all scopes need cooling down and maybe I’m being over dramatic.

 

[happy-kat]

Even the heritage needs cooling i just use my least powerful eyepiece when first observing. There's a picture of the mak on the heritage base as one member has that combo.

[John]

Refractors tend to cool quite a bit quicker than mak-casses. This is one of the main reasons that I have preferred refractors over mak-casses / mak-newts and SCT's for all but my largest aperture scopes.

 

[philj]

Ive used many different types of scopes for observing doubles over the years, achros, apos, newts, Maks, Cats and always found myself using a 4" F15 Achro out of as my first choice but my 5" ED Triplet is a close contender. I also have an 80mm F15 achro which gives a good account of itself. Nice clear and sharp airy discs in them make splitting much easier than with the reflectors I have used with softer.

[cotterless45]

Here's my opinion, completely biased ! But open to ideas  .

An achro refractor every time . Make it long tube to get at least f10. That'll make focussing easier with a long focussing range . As to what aperture , depends if you want to get as close separations as the seeing conditions will allow.

For visual , an achro will give you marble like stars ( diffraction discs) . 4" will give you great colour in single carbon stars , such as the Garnet Star and Hind's Crimson.

A long frac will need a sturdy mounting , but will reward you with the capacity for high magnification views.

You'll also find that long fracs are very kind on eyepieces, even basic zooms. You can also fit a Herschel wedge or white light filter to go solar. In addition ,clusters,planetary nebulae, lunar and planets will open up. Versatility makes achros proper scopes , fit for purpose.

One of the finest available, being the Vixen 102 ( old school). The best advice as mentioned above is to get to a club or star party and try before you buy,

Nick.

[Saganite]

2 minutes ago, cotterless45 said:

Here's my opinion, completely biased ! But open to ideas  .

An achro refractor every time . Make it long tube to get at least f10. That'll make focussing easier with a long focussing range . As to what aperture , depends if you want to get as close separations as the seeing conditions will allow.

For visual , an achro will give you marble like stars ( diffraction discs) . 4" will give you great colour in single carbon stars , such as the Garnet Star and Hind's Crimson.

A long frac will need a sturdy mounting , but will reward you with the capacity for high magnification views.

You'll also find that long fracs are very kind on eyepieces, even basic zooms. You can also fit a Herschel wedge or white light filter to go solar. In addition ,clusters,planetary nebulae, lunar and planets will open up. Versatility makes achros proper scopes , fit for purpose.

One of the finest available, being the Vixen 102 ( old school). The best advice as mentioned above is to get to a club or star party and try before you buy,

Nick.

Beautifully put Nick, and I would like to add  that my 5" f15 D&G on the self made pier in my garden is a thoroughbred for such a task, that has been so far, under used for said task. I hope to change that .

[wookie1965]

My Tal 100rs (F10) has given me plenty of great views of Doubles, Triples, clusters and Nebula's without Nick`s recommendation I would not have had as many nights out, with the 8" you need clear skies but even with a bit of cloud the Frac punches through.

[Dave In Vermont]

I just bumped into the picture below. As this concept was mentioned:

 

 

I like the GSO 90° Dielectric diagonal - frugal and excellent quality too. A win~win!

Dave

[leo82]

It seems it is 50/50 between the mak and frac, so much more pros for the frac with only a couple of cons such as the length and a better mount needed. The main thing is the view. I need to get to a club to see for myself but with 2 young uns it’s hard to get out at the times needed.

[chiltonstar]

3 hours ago, leo82 said:

It seems it is 50/50 between the mak and frac, so much more pros for the frac with only a couple of cons such as the length and a better mount needed. The main thing is the view. I need to get to a club to see for myself but with 2 young uns it’s hard to get out at the times needed.

...worth adding "aperture" to the cons for a frac. A larger Mak is affordable, whereas a frac of the same aperture is not (at least for most of us). Aperture is important for two reasons - you can split much closer doubles with a larger aperture, and limiting magnitude - larger aperture will show a fainter companion much more easily.

For many years, my main and only scope was a 4" (102mm) Vixen long focus frac - I still use it & love it, but I wanted to split closer doubles, hence going down the Mak route.

Nick above is right - go to a club and try a few scopes to see what suits you best, you may even surprise yourself and prefer reflectors!

Chris

[Timebandit]

3 hours ago, leo82 said:

It seems it is 50/50 between the mak and frac, so much more pros for the frac with only a couple of cons such as the length and a better mount needed. The main thing is the view. I need to get to a club to see for myself but with 2 young uns it’s hard to get out at the times needed.

 

Take the little ones with you if you can to a club or star party. Good night out for them and it's only a couple of hours . They may enjoy it and a great excuse to and have a look through a few scopes. As you still seem on the fence. Its only through your own eyes that will show you what you prefer, and better to try before you buy if you can before putting out hard earned cash. Personally I prefer frac views on doubles and planets?  

[leo82]

By young I mean 1 and 3 yrs old the times clash with their bed time routine. I put 1 to bed and the mrs puts the other one to bed. 

The frac I was looking at would be the evostar 120 whilst the mak would be the skymax 127. Earlier in the thread it says the aperture is most likely 119 for the mak

so they are pretty much on a par with aperature size.

[michaelmorris]

Cooldown times on SCTs and Maks can be significantly reduced by using a 'CAT cooler'.

http://www.lymax.com/

https://www.astroshop.de/geoptik-astrocooler-sct-celestron-8-fast-neuwertig-/p,800397

I have one of the Lymax coolers (bought secondhand) and I reckon it halves the cool down time on my SCT.  

The problem is that are very pricey.  Luckily, it's relatively simple to build something yourself.

http://homebuiltastronomy.com/sct/index.html

https://web.archive.org/web/20070731124722/http://www.starcrwzr.com/cooler.htm

https://web.archive.org/web/20130827121501/http://cotswoldobservatory.com/sctcooler.html