Splitting Antares

asimov (John) · #1 29-07-2005, 01:49 AM

How many people here have done it visually?

The reason I ask is, it is supposedly very hard to do. Conflicting reports on the internet, ranging from 'cant be done with a 6" scope' to 'Yep! did it easy with a 60mm!' From what I can gather, the only reason it's hard to split is because of the stark difference in brightness between the 2, therefore the brighter one throwing off rays & diffraction rings in the scope making the fainter companion hard to pick up ??

That would depend on the type of scope used then would'nt it? ie: no diffraction spikes in a refractor = easier to see than in a reflector (with a straight vane spider.)

RAJAH235 · #2 29-07-2005, 03:02 AM

John, I've done it in my 10" Dob, but using an off axis aperture mask. I made it from a piece of card stock & cut an 80 mm hole near the edge, so that it cleared the secondary. Tape to top of tube making sure that it also clears the spider. The seeing has to be pretty good, as this mask increases your f ratio. Mine goes from 4.5 to 14.25. It gives heaps of contrast & you have to use a fair amount of mag. (200X ++). Another trick, is to cut slightly smaller than 80 mm, square, hexagonal, triangular holes in card stock & cover the off axis mask 80 mm hole with the shaped mask. These 'flat masks' are then rotated, which also rotates the diffraction spikes, ie; moving them out of the way, allowing you to see the companion. This is probably best done by an assistant.
It's best tried when somewhere near zenith & on a good seeing night. Otherwise the flaring will negate the exercise.
I've tried doing a similar thing with Sirius, but without success. Too bright & too close to each other. Need more aperture. I've seen it in a 14" SCT a few years ago, when they were slightly further apart.
This will really test your collimation as well.
HTH.

L.

asimov (John) · #3 29-07-2005, 03:09 AM

So it would be no big deal, if for instance I was to split antares with my 6" achro refractor ?

asimov (John) · #4 29-07-2005, 03:15 AM

Actually, I made a mask similar to what you describe....3 round holes in it, so the holes just fit in between the spider vanes. The holes I cut are JUST small enough to fit in between the vanes, without actually getting the vanes in the view, if you know what I mean..At that stage, I was not into splitting stars though. I made that mask for jupiter.

RAJAH235 · #5 29-07-2005, 03:24 AM

Should do it with a refractor O.K. Try B/Band or UHC filter. I've heard this helps.

L.

gbeal · #6 29-07-2005, 06:36 AM

Not an easy subject. It depends severely on seeing, and a little luck.
I did it easily a couple of nights ago with my MN76, using an 8mm ortho. Once you do it, you can then back off the power a little and continue to split it, but again seeing plays the big part.
I have done it with the 10" f5 newt.
I have done it with my ED80/840 refractor as well. In fact I am looking to try this again, and also the AS63/840 refractor.
I don't really believe scope types are that big an influence, although for some reason the ED80/840 splits well.
One trick is to use an OIII type filter, and this evidently serves to reduce the glare of the primary, but allo some of the secondary to shine through (the primary and secondary are different colours).
I like to try when it is directly overhead.
Lastly remember that the secondary "leads" the primary, so if you watch the star(s) drift across the field, the secondary will lead.
Go for it.

ausastronomer (John Bambury) · #7 29-07-2005, 07:31 AM

I agree with Gary.

The type of scope is not critical, but reasonable to good quality optics helps a lot.

The important thing is good seeing and also that it is high in altitude.

I split it fairly regularly in my 10" dob and split it on a reasonable number of occasions previously in my smaller dobs (6" and 8"). I certainly don't need an aperture mask to split it in the 10" when conditions are favourable. Sometimes you need medium to higher powers 200X plus in the 10", on some occasions under excellent conditions it splits at 120X with a 10mm Pentax XW. As Gary mentioned an OIII or UHC filter helps but I don't find any assistance necessary in the 10", if it won't split I know its because of the conditions so I just move on.

I recently split it in Louies 4" TAK FS102 under good conditions using about 200X.

CS-John B

gbeal · #8 29-07-2005, 07:36 AM

Another good test, and nearby, is Nu Scorp. Double double.
Like Johns states, it will either split or not. If not, then move on.
Yes good and well collimated optics are essential, but not so much aperture.
I did hear of a guy in Canada ( a Zeiss freak) splitting it with a Telementor (Zeiss 63mm scope) which is why I am keen to try the AS63/840 Zeiss.
One day...............
One last thought.
Look to try it just on twilight, when the light is just enough to allow you to find Antares, I have found then the seeing is sometimes better, and it "seems" easier.

stringscope (Ian) · #9 29-07-2005, 07:41 AM

I have split Antares in both my 8" F6 Dobs. Seeing and tube currents appear to be the most important factors. My solid tube Dob splits it OK at 200X and above when the seeing is good altough always looks a little "messy". However, in my stringscope, when the seeing was good several weeks ago, for 3 nights in a row, I noted a beautiful split at 142X and up with very tight star images and well defined separation between the 2 components. I found it a beautiful sight. I don't know that the mirror is anything special in this scope, I put it down to good seeing, the lack of tube currents and the primary mirror boundary layer fans.

Last night BC came around with his new 10" GSO Dob. The seeing was only average at best. We could split Antares in both the 10" F5 GSO and the 8"F6 stringscope it was a "messy" image and the companion was only visible intermitently at 212X and it helped to know where to look. Not much fun to look at.

Cheers,

gbeal · #10 29-07-2005, 08:12 PM

Quick update.
Tried a bit of imaging tonight, but got clouded out.
Decided (as I had the wee 80mm on the mount) to try Antares.
Could not split it with anything other than the O-4mm (Zeiss 4mm orthoscopic) this giving 210x, and even then it was coming and going on the first diffraction ring. I was happy that I could see it though. Tried an O-6mm 160x and had glimpses, but not a real good split.
Tried Nu Scorp with the same magnifications and could split easily the dimmer of the two, and elongate/peanut the brighter of the two.
Tried also Beta Musca (another good'un) and split this with the O-4mm.
Magnification helps, but seeing is king.

asimov (John) · #11 30-07-2005, 12:56 PM

Hi guys. Thanks for all your comments. I actually split antares a couple of weeks back, using the 6" achro/aperture mask/15mm EP. But before jumping on here & yellin' out: 'I DID IT! I DID IT!' I thought I'd ask if it was a hard task or not first, lol. Something like splitting sirius sounds like a more worth while challenge. Antares was very easy. A beautiful sight though!

Cheers.

Starkler (Geoff) · #12 28-08-2005, 01:00 AM

Woohoo tonight I did it first time ever in my own scope

Tonight was my first night out in ages and the seeing was rather crappy so I was about to pack up. I was just playing doing a star test to check collimation and all of a sudden the seeing improved and rings on inside of focus were actually solid for a change

Actually it was good enough that I couldnt detect any difference between intra and extra focal diffraction rings

Great so as the seeing has picked up it was time to check Antares and sure enough I could see its little mate

davidpretorius · #13 28-08-2005, 07:09 AM

great thread asimov, striker's original lagoon imaging thread, ken's dumb things thread and this are my "best" threads for august. great subjects and then the way everyone gets behind it and discusses the issue and puts forward great ideas.

well done!

asimov (John) · #14 01-09-2005, 01:03 AM

Iv'e been trying to split antares off & on with the reflector lately & tonight I finally succeeded. The only way I could do it though was by using the 3 holed off-axis mask & baader contrast booster @ 212X. Then it was just a matter of gazing & waiting for moments of good seeing that were only coming once every 15 seconds roughly.

CosMos (Rich) · #15 01-09-2005, 05:58 AM

Saw the companion a few years ago through a long focal length 22" telescope. A beautiful green colour in contrast to the orange of Antares. If anyone is having difficulty seeing it, wait for an occultation of Antares by the Moon. Then the companion will appear from behind the Moon first. Or perhaps use an occulting bar. Worth seeing.

Rich

N1 (Mirko) · #16 21-05-2015, 10:16 AM

I knew there was a thread floating around here somewhere on this specific subject - So I'll register my recent observation of Antares B here as well.

14" SCT and 18" dob on 19/5/15, altitude around 70°, seeing 9/10, power ranging from 120x to 430x. Best at 220x (C14+OR18).

raymo · #17 21-05-2015, 07:53 PM

I split Antares repeatedly from the suburbs of Perth with my
150mm Skywatcher Mak. Beautiful sight. Never tired of doing it.
I have been unable to do it with my 8 and 10" Newts, or my old C-8.
I often regret letting the Mak go, in fact I would love the 180mm
version.
raymo

N1 (Mirko) · #18 22-05-2015, 09:22 AM

We did also try UHC and OIII filters just to see what they would do. To me, the results ranged between inconclusive, unsatisfactory and unaesthetic. I was unable to replicate what others on the net had reported, with Antares A supposedly showing a deep red colour in an OIII. It looked utterly green to me. The B component was seen, but it just didn't look good. A UHC seems a complete waste of time, because it produces double images that happen to be of similar colours to what you'd expect to see from Antares A&B. Unpleasant to say the least, with no way of telling what you are seeing. I understand others had different results.

I'm not convinced that either filter type is any good for this purpose, unless the objective is to split-and-forget, in which case the OIII might be of limited use.

Ryderscope (Rodney) · #19 22-05-2015, 09:39 AM

Just happened to trip across this post whilst scanning the 'new posts' listings. Timely in that I managed to observe the Antares companion last week at the SPSP. Was lucky in that a neighboring observer put me on to this object (thanks Brett) as I did not realise that Antares was a double star.

Observing details are a Meade 12" truss tube dob and 8mm 2" Ethos eyepiece. Object elevation at the time was about 40 deg and seeing was rather 'bouncy'. Observing required watching the object for some minutes at the eyepiece and waiting for those moments of clear seeing when the companion would 'snap' into view. In my scope the companion was sitting very close to one of the diffraction spikes. I think that this turned out to be an advantage as there were four of us observing and we all confirmed the same object position.

sn1987a (Barry) · #20 24-05-2015, 04:53 AM

I was looking at Antares earlier tonight in very good seeing with my 28. Great viewing Fanta Orange Antares with clear separation gap from a gleaming green Antares B. Quite a sight!.