First time double splitting

[wibblefish]

As a relative newbie I have been trying out various targets over the last few months (9 sessions so far, thank you UK cloud cover!) as I have read more and varied threads on this forum. Last night was clear and I decided to have a go at a few doubles I had seen mentioned in a beginners article. As it turns out I should have done some further research as quite a number of my targets were simply not in the sky at this time of year, lesson learned, be more prepared!

As I normally start off with Orion at the moment, I had a look at M42 with my new BST 12 and was very impressed with picking up clearer stars and with the addition of a BST short barlow was happy to see more of the nebula swirl detail than with my other EP (BST 25 / 18).

This led me on to my first double target Rigel, unfortunately I tried with numerous combinations and could not split the star. I also encountered quite a large degree of difficulty primarily with focusing to sharpness due to tripod shake which was not helped by a white halo thrown up around the star when using the 12 + barlow. I am guessing the halo effect is chromatic aberration encountered due to my short tube refractor being at high magnifications on a bright star (though I also a short barlow may also not be helping there).  

My next target was Castor, which I was able to see starting to split at 12mm and then clearly when adding a barlow. There were some CA effects but less so than I encountered in Rigel and I found focus easier perhaps as I was being more careful so there was less shake. 

My next target was Meissa in Orion but due to neightbours window lights I took a small detour to observe Mars with the new 12mm and 12mm + barlow combo. Again under barlow focusing there was some difficulty due to shake + haloing, to cut down some of the shake I got "ahead" of where Mars was and let it drift through the eyepeice (which it did at a speed which surprised me!) which helped. I could make out the distinct orange / red of the disc and some shadowing of the surface which was nice.

Back to Meissa I had some difficulty locating it due to my unfamiliarity with that area, I tried to split several of the stars but got absolutely nothing. I think I need to look at star maps (back to the be prepared motto) and get a better look at that area of the sky so I can make sure I am on target. 

Final target was the Beehive Cluster which I had failed to find the last time I was out. It prove elusive again as I was struggling with light pollution in the direction and a general inability to see any guide stars with the RDF. I shall have to really look into this one properly next time I as I had to rush about in the last 10 minutes of the session which didn't help.

Overall I had both highs and lows but I think the takeaway is I need to select my targets better! I also moved my telescope forward on the point of balance as I found a few times the barlow + 12 combo was moving things a bit faster than I would like. To try to combat the chromatic aberration I am going to try an #8 yellow filter in the end of the barlow / eyepiece, as I have a short tube refractor nothing will likely eliminate it but I am primarily looking for something to assist me with finding focus without as much halo distraction. Lastly it is clear the shake is going to be an issue with chasing doubles, I am going to try the old photography trick of suspending a weight underneath the middle of the tripod to see if that helps but I suspect I will need to purchase something more sturdy (likely the stainless steel skywatcher tripod) at some point - I think with new EP cost getting a new tripod will put me be beyond the cost of the initial telescope package which makes me wonder if its better to stop "upgrading" and just put funds towards another telescope 😕 I also tightened up the diagonal and the focuser pin so I am hoping that will help me be more "slow" with the focus.

If you have read to this point thanks this is probably mostly just waffle  

 

Edited January 18, 2021 by wibblefish

[wulfrun]

The main thing is you got out and gave it a go. In the process, you learned. Both are things to be proud of 🙂

[wookie1965]

Rigel is hard to split with it being a high mag star but the component is quite a bit dimmer. 0.3 and 6.8 have to good clear night with very good transparency I've tried with my 5" Refractor which Hass says will split it at 62x magnification but I couldn't. 

I would invest in a couple of more eyepieces

8mm and a lower mag a 18mm 

Great report some good targets there. 

Edited January 18, 2021 by wookie1965

[Sunshine]

Seeing is everything when it comes to cleanly splitting doubles. Doubles are a fav target of mine, some nights I just cannot split a particular double but, the next night I can.

Edited January 18, 2021 by Sunshine

[wibblefish]

Thanks for the kind words, I never know if its worth putting night reports / experiences onto here as I often think no one will be interested in my newbie rambling lol

@Sunshine @wookie1965 Yes, I suspected it might take a few nights of playing with various ones to see if I can split them but I was super impressed with Castor so I will definitely retry Rigel and find some others. I also read doubles are fairly good for the brighter nights  in summer so that's why I thought I'd have a go at it plus learning and finding new things to do with the telescope is always fun  

 

Edited January 18, 2021 by wibblefish

[wookie1965]

Doubles are easy on not so good nights if you pick the right ones if you look out and think won't be seeing galaxies tonight doubles are your friend. 

Get a good double book Sissy hass or Cambridge double star atlas which will help you. 

When I go on the computer I will post you a link to a site that has loads of doubles by constellations. 

[domstar]

Great report. Keep them coming. The reports section is my favourite part of the forum. It's good to hear about successes and failures. I can compare my observations, find new ideas and stay enthused when I haven't managed to be out for a while. I also enjoy double stars; they are beautiful and a challenge, both finding them and splitting them. Your session sounds just like how I like mine- some successes, some failures, something old and something new.

[wulfrun]

52 minutes ago, wibblefish said:

Thanks for the kind words, I never know if its worth putting night reports / experiences onto here as I often think no one will be interested in my newbie rambling

I would suggest it's always worth it. I'm very much a newbie too so your mistakes can help my learning by not doing the same. You also encourage other learners to go out and try things. In addition, more experienced members can comment constructively and suggest ways to improve.

[wookie1965]

http://web.archive.org/web/20170419050003/http://astronomy.eaglecreekobservatory.org/doubles/

Here is that link I said I would post to you.

Edited January 18, 2021 by wookie1965

[Pixies]

The Beehive cluster can be hard to find under light pollution, as Cancer is not very conspicuous. They are a good target for binoculars, as you can use them to scan the area, about half way between Castor/Pollux and Regulus.

What tripod/mount do you have? There's nothing more dispiriting than a wobbly mount!

And keep at it with the reports, it's great to hear others' progress.

[wibblefish]

17 hours ago, wookie1965 said:

Rigel is hard to split with it being a high mag star but the component is quite a bit dimmer. 0.3 and 6.8 have to good clear night with very good transparency I've tried with my 5" Refractor which Hass says will split it at 62x magnification but I couldn't. 

I would invest in a couple of more eyepieces

8mm and a lower mag a 18mm 

Great report some good targets there. 

 

15 hours ago, wookie1965 said:

http://web.archive.org/web/20170419050003/http://astronomy.eaglecreekobservatory.org/doubles/

Here is that link I said I would post to you.

Thanks for that I will definitely check those targets out! I probably need to start keeping a list of targets so I can build up a nights set of viewing rather than just pootling up to the eyepiece (not that that isn't fun!).

I have an 18mm and a 12mm, those plus a barlow gets me to 9mm and 6mm respectively or are you suggesting an 8 might be a more useful magnification for better viewing + the option to go to 4mm with barlow? I think from calculations that it probably as far as I can bump this telescope though whether it'd be a useable magnification would be interesting  

I have my eye on the Cambridge double star atlas when it becomes more available again, I get the impression its gone out of print at the moment for some reason - sissy haas definitely has alas.

13 hours ago, Pixies said:

The Beehive cluster can be hard to find under light pollution, as Cancer is not very conspicuous. They are a good target for binoculars, as you can use them to scan the area, about half way between Castor/Pollux and Regulus.

What tripod/mount do you have? There's nothing more dispiriting than a wobbly mount!

And keep at it with the reports, it's great to hear others' progress.

Thanks, good tips, I was sweeping with binoculars trying to find it but I feel I was in the wrong place in the sky, I think I need to sit with a star map / app and work out some guide stars like those I can hit with the binoculars before attempting to throw the telescope at it again (the RDF literally sees purple / orange glow in the same space)

The telescope says it is AZ pronto but I have a suspicion from the pictures of the az pronto mount it is more an AZ pronto mount head on a standard sky-watcher aluminum tripod. Its fairly stable ordinarily (non-high mag), easy to move around and handles the telescopes weight (not that there is much of that!) fairly well.

 

 

Edited January 19, 2021 by wibblefish

[wookie1965]

It's always better to look through less glass I. E without the Barlow you can then see more clearly, a good Barlow is an asset better on clear transparent nights. 

You could check here 

https://www.rothervalleyoptics.co.uk/the-cambridge-double-star-atlas-2nd-edition.html

I have the first edition as a PDF not sure I could email that with it being 15.6mbs

I will look later maybe able to upload it to Dropbox. 

[wibblefish]

43 minutes ago, wookie1965 said:

It's always better to look through less glass I. E without the Barlow you can then see more clearly, a good Barlow is an asset better on clear transparent nights. 

You could check here 

https://www.rothervalleyoptics.co.uk/the-cambridge-double-star-atlas-2nd-edition.html

I have the first edition as a PDF not sure I could email that with it being 15.6mbs

I will look later maybe able to upload it to Dropbox. 

Aye I will add it to the growing list of upgrades lol I swear I will have spent double the cost of the initial telescope by the time I am done. Still I was planning to keep the telescope for a year or two (at least) and any bits can be moved the next one I am sure   (the wife will believe that right?! - this is the trouble with working from home everything comes to the door so no random sneaky purchases 😛)

Thank you very much but don't worry overly about the PDF I am trying to collect print books for astronomy, they just seem to be more useful (and I can take it outside with me!). I will have a look at the various suppliers though I didn't realise they did books as well as equipment  

Edited January 19, 2021 by wibblefish

[Pixies]

Camcer (and M44) is pretty much half way between Pollux (Gemini) and Regulus (Leo).

Regulus, Procyon and Pollux (with Castor) make up a pretty conspicuous  triangle in the Eastern sky:

I just usually plonk my binoculars half-way between Regulus and Pollux and the Beehive cluster is there or thereabouts.

[Bongo]

23 hours ago, wibblefish said:

Thanks for the kind words, I never know if its worth putting night reports / experiences onto here as I often think no one will be interested in my newbie rambling lol

Well, I certainly am! I'm also pretty much a newbie and its good to hear someone going through similar things to me. It helps give a feel for which trials/tribulations are common to all and which are my very own. 😉

[wibblefish]

@Pixies hmmm I feel like I was in totally the wrong place which is odd considering I was using my phone app, will definitely swing the binos in that direction next time I am out to see, appreciated!

@Bongo I will have to keep more detailed notes and plan a bit better in order to actually have more to say! Definitely going to try my hand at doubles again next light so I will try and update this thread if I do!

 

[John]

I came across this simple list of 100 double stars which might help you identify some suitable future targets:

doublestarlist.pdf

[lunator]

Hi Wibblefish

Rigel can be a tricky split. It is quite low from the UK.

Bruce MacEvoy has a rule of thumb that implies Rigel would take about x80 Mag to split.

In my experience this rule can be slightly optimistic and I would go for a higher Mag say x100+ if you can. Once you have split it you will be able to see it with lower magnification.

Cheers

Ian

[wibblefish]

18 hours ago, John said:

I came across this simple list of 100 double stars which might help you identify some suitable future targets:

doublestarlist.pdf 47.6 kB · 14 downloads

Thanks, thats a great list

8 minutes ago, lunator said:

Hi Wibblefish

Rigel can be a tricky split. It is quite low from the UK.

Bruce MacEvoy has a rule of thumb that implies Rigel would take about x80 Mag to split.

In my experience this rule can be slightly optimistic and I would go for a higher Mag say x100+ if you can. Once you have split it you will be able to see it with lower magnification.

Cheers

Ian

Hi Ian, Thanks, I think I was running at about 110x magnification according to the fov calculator I just ran through 90mm apeture / 660mm focal length + a BST 12mm and x2 barlow  I suspect it was more down to the CA glare masking the smaller secondary, now I have done a little more research into what I am looking for I will give it another go next time and see if I can spot it! 

I spent last night tightening up some lose bolts across the tripod to see if that will help with the shake at high magnification with and my light yellow filter arrived to see if it might reduce the CA slightly to assist focus so I am all set for another go whenever the skies next clear  

 

[MylesGibson]

I did a topic on double stars awhile ago which you may find interesting if you are enjoying the challenge of splitting stars!

This one is focused on doubles which have colour contrasting components, there are 2 nice winter ones about; SAO 173349 (or HD56577) in Canis Major and Iota Cancri in Cancer. Both of these are easily split and have a nice blue/yellow or blue/gold pairing which is quite pleasing!

Keep it up, splitting doubles is challenging, but rewarding!

Edited January 20, 2021 by MylesGibson

[wibblefish]

2 hours ago, MylesGibson said:

I did a topic on double stars awhile ago which you may find interesting if you are enjoying the challenge of splitting stars!

This one is focused on doubles which have colour contrasting components, there are 2 nice winter ones about; SAO 173349 (or HD56577) in Canis Major and Iota Cancri in Cancer. Both of these are easily split and have a nice blue/yellow or blue/gold pairing which is quite pleasing!

Keep it up, splitting doubles is challenging, but rewarding!

Thats great I will have a read I picked out some targets the other night and I vaguely remember one being in Canis Major will have to consult the list!

Next session notes at the moment I have:

- Rigel, another go with new filter and some more knowledge see if it makes a difference

- Beehive, bino sweep and then some actual time rather than squeezing it in

- Almach, gold / blue double

- I CAS, triple likely be to hard but will give it a go

- 40 ERI, unequal double

- BETA MON, white triple

- 145 CMA, gold / blue double

I have no idea how suitable the targets are though (will do some more research) but I think I at least checked they are in the skies this time (though I haven't checked they clear the local buildings admittedly!). 

 

Edited January 20, 2021 by wibblefish

[John]

I find this a great online resource for data on double stars:

https://www.stelledoppie.it/index2.php?section=1

 

[Pixies]

Iota Cas is my fave multiple star system to observe. It's a bit of a challenge, you'll need reasonable seeing (and reasonable collimation if using a reflector). x100 - x150 magnification will split them.

Probably best to do it earlier in the session as it will be getting closer to the Zenith the later it gets.

Make a note of the colours you see. 

[Bongo]

22 hours ago, wibblefish said:

I will have to keep more detailed notes and plan a bit better in order to actually have more to say! 

Yeah, same here. I think there's a point when I'll have to actually start planning things out, rather than pointing the 'scope at anything that catches my eye or springs to mind while I'm out there. Not that the latter strategy hasn't been good fun, of course! Given the scarcity of decent clear night - got to make the most of those brief windows of opportunity, I guess.

[MylesGibson]

Also, if you are around the Beehive, there is another good triple system, Tegmine (Zeta Cancri) if I recall the name correctly! All reasonably well matched in visual magnitude. I've always liked that one. Splitting into 2 is fairly easy, but trying to get all 3 is a real challenge. I think I've only managed it the once with exceptionally good seeing. I must have another go soon!