More on the Pup......

[chiltonstar]

As the weather this week here has been "patchy", with some open sky, clouds, rain and a lot of dew, I've been using my "grab 'n go" scope (ED80) to look at some of my favourite doubles as the scope only takes a couple of mins to cool down, and I can get it back inside quickly if needs be.

Castor showed the seeing to be extremely good at times, with two different-sized silver disks, well separated (4 arcsec), with perfect diffraction rings - as good as I've ever seen this showpiece double in any scope! The faint companion was a cocoa-ish colour, rather than the orange listed. Optimum mag was x160.

As the seeing was so good, I had a try at Sirius, not really expecting any success of course.... However, I got the Pup very easily, even without the red filter, the Pup being a very sharp pinpoint in the halo round the primary! Filtration improved the view a bit, but not as much as with my 5" Mak where there is a very real improvement. Must be something to do with the lack of scattered light from secondary surfaces, I suppose.

The Trapezium was very clearly separated (A, B, C & D), but I struggled to see E, and couldn't get F at all - a consequence presumably of the small aperture of the ED80.

Sigma Ori was superb - better colours than I get in my 5" Mak, and again, very sharp pinpoint stars.

Next stop, a lottery win and a 6" frac.......

Chris

[Stu]

Impressive stuff Chris, the seeing must have been very good. Makes me think it might be worth having a crack with my 4". Need to get away from all the houses and heating flues around home though.

Stu

[John]

I've not managed "the Pup" with either my 102 or 120 ED refractors as yet. The 120 was probably close last time I tried with it but, like Stu, I'm viewing Sirius through a gap in houses and there are lots of heating plumes around this time of year.

Outstanding result to get it with the ED80 Chris. I feel your eyes might have something to do with it as well though as I've noticed that you manage frequently to crack more challenging objects with your scopes than I've been able to with mine

Perhaps you have better skies too ?

I do have a 6" F/12 refractor though so, when thats up and running, I'll give that a try on Sirius as well. It should be an excellent scope for splitting binaries.

[Stu]

I've not managed "the Pup" with either my 102 or 120 ED refractors as yet. The 120 was probably close last time I tried with it but, like Stu, I'm viewing Sirius through a gap in houses and there are lots of heating plumes around this time of year.

Outstanding result to get it with the ED80 Chris. I feel your eyes might have something to do with it as well though as I've noticed that you manage frequently to crack more challenging objects with your scopes than I've been able to with mine

Perhaps you have better skies too ?

I do have a 6" F/12 refractor though so, when thats up and running, I'll give that a try on Sirius as well. It should be an excellent scope for splitting binaries.

I definitely agree with your comments about Chris' sight John, I am sure visual acuity has a lot to do with success in these observations and my sight is average at best.

Will have a go from a better site at some point.

Stu

[chiltonstar]

Maybe it helped that I'd just cleaned up the optics of the scope - I cleaned the front surface of the objective with a solvent wipe, as well as the diagonal mirror and the EP. The level of halo round any bright object is extremely low with the ED80 anyway - far less than my 5" Mak or my 4" frac. I suspect that Pup-spotting is more of a contrast and scatter issue than being aperture dependent, cf splitting a very close pair??

Chris

[John]

 I suspect that Pup-spotting is more of a contrast and scatter issue than being aperture dependent, cf splitting a very close pair??

Chris

I think you are right Chris. The separation of the pair is around 8-9 arc seconds so not particularly challenging and slowly widening too. It's the vast brightness difference plus the relatively low altitude that is the challenge. If Sirus was closer to the zenith I double it would be anything like the challenge for us in the UK !

[chiltonstar]

I think you are right Chris. The separation of the pair is around 8-9 arc seconds so not particularly challenging and slowly widening too. It's the vast brightness difference plus the relatively low altitude that is the challenge. If Sirus was closer to the zenith I double it would be anything like the challenge for us in the UK !

I'm lucky that at the moment at about 23:00 - 23:30, Sirius is above open fields from where I am, with no house or heating duct in line at all; the odd flatulent cow perhaps on occasion.

Chris

[alan potts]

Nice one Chris,

Your one up on me as I have not managed the Pup this year so far, largely due to me not staying up long enough. Getting it with a 80mm is quite something but as I have said many times as have others. it is all about conditions.

Alan

[John]

Nice one Chris,

Your one up on me as I have not managed the Pup this year so far, largely due to me not staying up long enough. Getting it with a 80mm is quite something but as I have said many times as have others. it is all about conditions.

Alan

I've not split it so far this year either Alan. I've tried a couple of times with my ED120 and once with my 12" dob but Sirius was just not quite "tight" enough to see the glimmer of the Pup on those occasions.

My "window" for Sirius lies between my neighbours roof and some large chestnut trees. It's over a school but at least the heating there is off at the time of night I'm usually observing.

[alan potts]

John,

I firmly believe it is difficult enough to split from the UK as it is, I never did it years ago back in the 70's with a 12.5 inch Newt. I think you are a bit better off than I was then with living in Somerset but there is no subtitute for moving a thousand miles south of that. I have in the last 4 nights spent about 41/2 hours on Sirius and I am getting nowhere, I am however only observing up to a point that it gets in the UK at the moment, this is purely so I can see what you are all up against. It may sound silly but it is just my way of trying to understand what you all go through. So far my best shot was with the 115mm APO so I really think you will get it with the 120mmED, the trouble it I feel you need it at the highest elevation it reaches and it sounds as if you can't see it then.

Alan. 

[John]

John,

I firmly believe it is difficult enough to split from the UK as it is, I never did it years ago back in the 70's with a 12.5 inch Newt. I think you are a bit better off than I was then with living in Somerset but there is no subtitute for moving a thousand miles south of that. I have in the last 4 nights spent about 41/2 hours on Sirius and I am getting nowhere, I am however only observing up to a point that it gets in the UK at the moment, this is purely so I can see what you are all up against. It may sound silly but it is just my way of trying to understand what you all go through. So far my best shot was with the 115mm APO so I really think you will get it with the 120mmED, the trouble it I feel you need it at the highest elevation it reaches and it sounds as if you can't see it then.

Alan. 

Thanks Alan,

I managed to bag "the Pup" tonight with the 12" dob. It was tough though as the conditions were not bad but not perfect. I needed the 7mm and 6mm Astro Hutech orthos to get the best view. When I say "best" we are talking about the Pup faintly glimmering though Sirius A's diffraction sparkle during moments of steadier seeing. But thats much better than not seeing it at all

[alan potts]

John,

Very well done, seems I am lagging behind this year after doing very well last. I did read about this in a book by, I think SPM, something like, this star can be split with a fairly small telescope on some nights whereas on others even the worlds largest scope cannot split it. This may be a bit of an exaggeration but I think he always had a way at getting a point across. If it is true word for word we are all doing rather well.

Alan

[wxsatuser]

Well done on the split.

When I built my obsy I knew I would'nt see it from there.

I'm going to have to go portable to the front garden and it may work.