Double Star Splitter

[Raktajino]

I am considering buying a Bintel 12" Dob - mostly for its aperture / resolution and for visual observing. Can anyone tell me what would be needed to make this into a reasonable double star splitter? My educated guess is a decent barlow or some low mm eyepieces. The proposed scope is only an f/5 and for double star splitting I need to crank it up to say around f/10. Is using say a 6 mm eyepiece (as opposed to a 12mm eyepiece) or a barlow the same as doubling for f ratio?

Other than the above setup - what do people consider an ideal star splitter setup?

[Radar]

Hi Raktajino,

Double star splitting with a 12" dob is going to be nice and easy. Whenever you use a barlow you double the F-ratio. So simply putting in a barlow your scope will become an F10. If you were to double stack your barlow, you'd have an F20 telescope (quite common for planetary work etc).

As far as what an ideal star splitter scope would be, aperture is the key ingredient in my opinion. I think a 12" dob is spot on for what you want to do. As far as eyepieces go, a high, medium and low power eyepiece should cover all your views for splitting stars.

Where abouts are you based?

Regards

Ray

[timthelder]

Can anyone tell me what would be needed to make this into a reasonable double star splitter?


Hi Rak,

Not sure if this helps, but I can easily split doubles with my 9 1/4",235mm, f/10 scope.A 6mm lens and a good quality barlow(ED)should do it pleasingly enough.(actually a 9mm lens should do also well.)

The "double-double" in epsilon lyrae is exciting to see when the scope splits that one star into four.

Note:The scope does need to be well collimated.

[Raktajino]

Ray,

Thanks for that. It's what I thought, but good to hear confirmed. I'm in Wagga NSW. I'm on the western edge so there is slight light pollution to the east of my backyard but otherwise some pretty good dark skies.
I also suspected that good collimation is the key. At the moment I've got a 4.5" newtonian that's got shocking spherical abberation. It's fine on the moon and the Sun (with the filter) but point to anything else, especially planets and its a loser. Having said that though, I did manage to split alpha centauri - just. That was more a buzz that I thought it would be.
At the moment all I've got for collimation is a $10 purpose made lens-cap type collimator - i.e. with a pin hole in the middle. I know very little about collimators, but would be prepared to spend some money on a good one. What do people recommend?

[rmcpb]

A 12" dob will do just about anything you want. It will surely split doubles as the large aperture will give you finer resolution than a smaller diameter and that is what you want. As for the collimation, it goes without saying that any scope should be collimated to get the best out of it for any task.

Wish I had your skies even though mine are good we always want more :)

[Radar]

Hi Rak,

Yeah collimation can be frustrating at first but there are some great products coming onto the market which have taken the guesswork out. Things are getting easier all the time in the collimation world.

This product in the following thread is proving quite popular among astronomy circles. I haven't used this product, but I'm yet to see a bad review on it.

http://www.myastrospace.com/forums/showthread.php?t=911&highlight=collimator

http://www.astrosystems.biz/images/Blaser.JPG

What make is your 4.5 newt?

Cheers

Ray

[Raktajino]

Hi Radar,

My 4.5" Newtonian is a Meade DS-2114S GOTO. I removed the plastic barlow and it is not bad for the sun and Moon, but anything else and the spherical abberation kick in. Collimation is a pain. When I get round to buying the Dob and a decent collimator (thanks for the link on that), my observing should go to a new level.

Rod

[Radar]

With a new scope, your observing certainly will go to a new level. Observing is limited by optics in most cases. In fact, once you get some sharp optics and good collimation, you'll discover the sky all over again.

When are you aiming to buy the new scope?

Ray

[Raktajino]

Ray,

I'm planning to buy from Bintel, but am open to suggestions. I've bought from Bintel in the past, they offer good friendly advice, and their service is excellent. BTW I don't have shares in the company!

Rod

[Radar]

BTW I don't have shares in the company!


lol, are you sure?

I agree though, I have also had good expereinces with Bintel.

Ray

[AstroBob]

The "double-double" in epsilon lyrae is exciting to see when the scope splits that one star into four.


this sounds like a fun target. I didn't realise that it existed. I'll have to spy it sometime.