Pup companion star of Sirius.

[Guest]

I was reminded of the only time that I saw The Pup companion star of Sirius.

Many years ago with an 80mm f16 achromatic doublet. Observing Sirius two nights ago with my 127mm triplet, I just cannot imagine how it could ever be seen. This was because of the severe twinkling of Sirius. The image of Sirius never appeared stable. 

I also have a Celestron C8. When I collimation it,I will try again. But what experiences have you had observing The Pup star? What telescopes, eyepieces and filters have been employed in your quest to observe The Pup?

[John]

I've managed to see "The Pup" quite often with my 12" dobsonian. The best eyepieces have proved to be low scatter ones in the 7mm-5mm range (227x - 318x). Orthoscopics and the excellent Pentax XW's show it best but I have also seen it with my 6mm Ethos. Unsteady conditions can render the task much harder or impossible and "the Pup" does have a tendency to "come and go" if the seeing is less than very good. It's not actually that close to Sirius (around the same split as Rigel and it's companion star) but the huge brightness difference and low altitude combine to make it quite a tough cookie !

As yet I've not seen this in my other scopes but to be fair I have yet to try my Tak 4" and TMB / LZOS 5.1" refractors on it.

 

[Moonshane]

I have only seen it once at an SGL party where I was looking across fields rather than rooftops as I usually do. That was with my 16" dob.

I have seen hints with my 120ED and 6" f11 but never been convinced enough with them.

[xtreemchaos]

ive seen it Few times over the years, the lasttime was last January with my AR127l 4x barlow and 15mm eyepeice, the seeing has to be cracking and then its hit or miss , wait until its high. clear skys charl.

[Paul73]

Might be worth a shot tonight.

Have never really gone after this one. Mostly because Sirius is so so bright.

Paul

[John]

I spotted it during this session on 2nd January (last target mentioned):

https://stargazerslounge.com/topic/284453-pretty-good-haul-of-objects-0203-january-2016/

 

[YKSE]

I've seen the pup a few times over the years. The best one was with 120ED on a night ecceptional good seeing, Sirius was dead steady naked eye, not a single flick. My rule of thumb for going for pup is:

If Sirius twinkles faster than about 1 beat/second in naked eye, I don't try to find the pup, look at something else.

[Guest]

Do you think that a Celestron C 8 SCT telescope would resolve the pup. Bearing in mind that the telescope does have a larger inch for inch central obstruction compared to a Newtonhill?

[YKSE]

Sure C8 is capable of doing it. I did with mine, under very good seeing (less than perfect  though). It just needs  more preparation, such as long cooling time (> 2 hours), very good collimation. With current seperation of pup, we don't need go crazy with magnificaiton, less than 200x is enough when seeing is very good.

[Paz]

I've not yet split this. My most fun experience with Sirius is defocussing on it before my scope has cooled down. This results in a sparkling multicoloured disco ball!

[popeye85]

Would a filter help with this task to reduce the glare of Sirius? (Sorry still trying to work out the technical details of how filters work-I'm not that brainy!!) 

[John]

It might help. It's said that a red filter can help with Sirius. There was a thread on this subject in 2015:

https://stargazerslounge.com/topic/233306-observing-tight-double-stars-with-colour-filters/

 

[YKSE]

Yes, i've used red filter to see the pup too, after Michael's advice, that was some time ago

3 hours ago, Paz said:

I've not yet split this. My most fun experience with Sirius is defocussing on it before my scope has cooled down. This results in a sparkling multicoloured disco ball!

When the seeing is not good, you'll see a rainbow-coloured Sirius in focus too, even if the scope is proper cooled. Of my experience, Sirius shows only slightly elongated  shape of blue and red colour, when seeing is very good, the best one I had was colourless, pure white.

[Dave In Vermont]

Many filters have been tried. Many worked, and many of the same filters have failed. It's that uncertainty that's a big lure for many of us. I've yet to try, but I'd likely start with a two-piece polarizing-filter. Some folks swear by masking out Sirius altogther with different gizmos and set-ups.

In the last analysis - bagging the Pup is grounds for celebration! It seems to require a perfect-storm of 'seeing' conditions and telescopes - with no guarantee what works one night, will work the same way the next.

Good Luck!

Dave

[alan potts]

I have done Sirius many times with pretty much all of my scopes. Though it has to be said that I have only seen it once with the 12 inch SC, why I have no idea, it is not as if I don't know how to collimate it correctly. I find it fairly easy with the M/N 190mm on a power of around X100 on a good night when it is well placed.

For about two years I played a game, this was trying Sirius when it is at levels that you see it from in the UK, IE not allowing above about 22 degrees from the horizon, after that a split will not count. I have to report that even though I have attempted this many time I have only been sure of seeing it twice and once that was with an 18 inch scope, so it sort of shows how difficult it can be.

I too have seen Sirius like a Pink Floyd lightshow but I have also regularly seen it absolutely still, so this is clearly conditions, when it is without scintilation I have split it easily, it is one of my favourite targets.

Alan 

[Guest]

Many of the successful views of The Pup have been with larger diameter objectives. And on the other hand it is the excessive light from Sirius that is the problem. I agree, it's like trying to put a pint into a quart

 Or is it the other way round?

I also have a 127mm triplet refractor and would imagine that this may work.

[John]

Seeing a star of the brightness of "The Pup" does not need much aperture but it's close proximity to the brightest star (apart from the Sun) adds a wealth of challenges to prizing the two apart.

This image of Sirus A & B is from the HST but it illustrates the challenge. The "B" star is 10 magnitudes fainter than Sirus A. Strangely, the HST view is not unlike the view I get with my 12" dob of this target except the "B" star is even fainter. This must be the only instance where my scope can even remotely rival the HST !

 

[JOC]

Last night and the night before, we chanced upon Sirius for the first time.  Two nights ago we had spotted her, but didn't know what it was.  So psychedelic in the sky that we thought it was an aircraft pulling directly away from us, until it was still there 20 minutes later, then we wondered if we had the ISS in our sights, we looked at her and she twinkled and twirled just like the disco ball described above, red, blue, orange flashes of green and apparently fluctuating in size and no way of getting it in focus.  It was a really pretty object, my son named it the 'raving party star' .  So last night I got out again and remembered to fire up Stellarium - Sirius looked to be the only sensible suggestion and reading above was def. what we were looking at, it was twinkling and flashing all the various colours again.  I hadn't seen the thread above at that point, but the only filter I have is a two piece polariser,  so as she was so bright I put a single section on the bottom on the eyepiece (as I'd seen in a YouTube video) and took a look with just that.  It calmed the flashing down and steadied the view somewhat - I tried the other section of the filter on the top of the eyepiece, but in any orientation, this was too much and really reduced what I could see.  So if anyone has a two part filter and knows what they are doing (which I don't), it might be worth trying just half of the polarising filter.

[Les Ewan]

Ive tried many times with my 12" Dob without success the trouble is from my site just a whisker off 56 deg North the maximum elevation is only about 17 deg. Plus the fact my dob is a budget scope mainly for low power fuzzy work.

[Paul M]

On 05/01/2017 at 21:37, Paz said:

I've not yet split this. My most fun experience with Sirius is defocussing on it before my scope has cooled down. This results in a sparkling multicoloured disco ball!

That's pretty much my experience with the old Dog too.

Sunglasses and factor 50 sunscreen

[alan potts]

I have seen the Pup many times but it has to be said from a better position than anyone in the UK. Even though I tried many times with the 12 inch SC before I had other scopes I was unable to pick it out, why I do not know, there was nothing wrong with the scope. I have found it easiest with the 115mm APO and the 190mm m/n by Sky Watcher, both have given me clean sights of it but only when conditions are good. I have also seen it with my 18 inch on a number of occasions. I started to play a game out here which I have reported many times over the last few years. The game was to only try Sirius when it was at heights above the horizon that you find only in the UK, here I am about 11 degrees better off at best. One gets a different set of result using this system with only 3 hits in many attempts and even then it was at the sort of attitude you would find in the southern parts of England, I have never seen the pup when the star is below about 19 dgrees above the horizon, apart from one time early morning in superb conditions and even then it was at about 16 degrees, so nothing dramatically different.

I have also tried many times with the 70mm ED I have piggybacked on the SC and so far not managed it. Most times I have been able to see the Pup with no more than about X120, for me conditions is the key word.

Alan

[JOC]

So why does it twinkle, sparkle, dance and generally do the 'multi-coloured disco ball' routine, is it just down to its position above the horizon and the fact that it is viewed through a lot of atmosphere?  If so does that effect happen to other stars in a similar position above the horizon?

 

NB.  John - that picture above is the 'pup' that tiny dot of light at about 7 o'clock to main star between the flares in that picture?

[alan potts]

JOC, Purely to do with the atmost phere, you will find the lower it is the worse it gets. Last night it was absolutely stable here but when it was at least 26 degrees above the horizon, we have very still air the last few days but rather chilly at minus 16.

Alan

[alan potts]

JOC, the Brightness also exaggerates the effect which is called scintillation. You don't see it on planets as much as you are seeing a disc as oppossed to a point source of light. You do see it on all stars but it is no as noticeable, take Rigel for example, that to will twinkle but nowhere near as obvious as Sirius.

Alan

[Jason D]

Once I understood what to look for, finding the Pup became much easier with my 10" reflector. I even managed to capture it years ago holding my iphone against the eyepiece.

Jason