Time to get serious about Sirius

[jock1958]

1 hour ago, John said:

I'm around the same latitude as you. As I said in the opening post, my challenge this winter is to spot the Pup star with my FC100-DL and my Skywatcher ED120 because I've not managed it with those scopes as yet.

The challenge just now is to see any stars at all - it's been pretty solidly cloudy for the past few nights

 

4 minutes ago, F15Rules said:

Thanks Iain😊..

Your Tak should be able to do it, my first ever view of the Pup was with my then Vixen ED103s, and it just happened that one very steady night..

Keep at it, I was looking long and hard for some time before I could be sure of my sighting the other night (and I should say I could only see it with my left eye, not my right, which has deteriorated in recent years).

Dave

Cheers John & Dave will keep on battling the elements and my latitude, you never know 2021 might be my lucky year🤞

[John]

First chance tonight since I posted this thread.

I took the "sledgehammer to crack a nut" approach with the 12 inch dobsonian. I didn't think the seeing was that great but E & F Trapezium were showing fairly easily so I gave Sirius a go when it rose above the rooftops.

Once my eye had adjusted to the glare from the star, I found that I could spot the Pup star fairly readily as a point of light gleaming shyly though the outer "skirts" of the glare from it's far brighter companion using 268x (6mm eyepiece). The Pup star was trailing Sirius A as it drifted across the field of view. I was able to repeat this at 199x (8mm EP0 and 338x (4.7mm EP) but I think that the 6mm made things just a touch easier.

Pleased to see the Pup again for the first time this season

 

Edited January 7, 2021 by John

[bish]

Must admit I have never tried to split them. I rarely get excellent seeing so never attempt it. Good tip about Rigel and I will have to check out Beta Monoceritis.

[John]

Last night I was observing Sirius A and B again using my 12 inch dobsonian. The gap between the pair is currently about 11 arc seconds so about as wide as it gets during their 50 year orbit.

The actual distance between Sirius A and B varies between 8.2 and 31.5 AU so at their furthest apart a distance similar to that between the Sun and Neptune lies between them. At their closest approach the distance is a bit closer than the Sun - Saturn gap.

So the above gives a little idea of the scale of what we are observing over the 8.6 light years between us and the Sirius system.

With Sirius A being about twice the physical size of the Sun but 25x more luminous and Sirius B about the physical size of Venus, the system would make a fascinating spectacle from, say, .5 of a light year distance I would think

 

 

 

 

 

[Les Ewan]

I've spent many hours over the years to  spot the Pup with 8" and 12" Newts. Over the last couple of years I've tried even with a 16" and failed. Conditions were close to ideal last night for binaries  and spent twenty minutes trying last night still failed. Tried different filters even stacked filters still nothing. I'm starting to give up hope of ever seeing it with the conditions at 56degrees north despite and equipment I've got. 😡

[GordonD]

I spent quite some time on Thursday and Friday evenings trying to get the pup with my 12" dob in reasonably good skies, but I am afraid I just could not see it. A hint of something perhaps, but never anything certain. Rigel B was clear bright and well separated at the same times. Anyway a good one to keep trying for over the next month or so. Determined to bag this one now! I have deliberately avoided looking up where it should be, to avoid imagination taking over.

[John]

Tonight it is the turn of my 130mm triplet refractor to try and split Sirius A & B.

I particularly wanted to compare the performance of 2 diagonals at this task - an Astro Physics 2" Maxbright and a Baader T2 Zeiss prism.

The seeing is quite steady although there are bursts of scintillation of Sirius from time to time with more settled periods of a few minutes in between those.

I was able to see Sirius B, the Pup star, for short periods at 300x magnification using both diagonals. On this particular occasion, neither the prism or the dielectric mirror seemed to have any advantage.

The eyepiece used throughout these comparisons tonight was the Nagler 2mm-4mm zoom in the 4mm setting.

Splitting Sirius with the 130mm refractor is a harder business than with my 12 inch dobsonian of course. Sirius itself is generally more tightly defined with the refractor but the Pup star proportionately dimmer too. The Pup seems to lie just outside the halo of glare from Sirius A with the refractor image whereas with the 12 inch dob, the dim companion star shines through the more extensive halo.

So tighter control of light scatter from the refractor (this did not change with the diagonal used tonight) but a dimmer Sirius B to search out.

Another factor that comes into play for me when observing this target is moisture over my eyeball. This seems to be connected with being tense and probably "trying too hard". My eye gets a little more moist for a short while which increases the scintillation of the very bright Sirius A. When I take my eye from the eyepiece, give it a short rest and then observe again in a slightly more relaxed manner, Sirius seems to settle, it's form is more regular and the B star becomes attainable again.

Cloud cover is increasing now so that will soon put an end to this session. Next time it is clear with reasonably steady seeing I will see if I can repeat this exercise with my ED120 refractor.

 

Edited February 3, 2021 by John

[JeremyS]

Fascinating write up John. And nice result.👍

[RobertI]

Excellent result John, interesting commentary. Look forward to hearing how you get on with the ED120. Although encouraged by your excellent post, Sirius lies close to the rooftops from my garden and I will have to take a trip to a site with a better horizon if I am to try this. I may run out of time this year ......

[John]

36 minutes ago, RobertI said:

Excellent result John, interesting commentary. Look forward to hearing how you get on with the ED120. Although encouraged by your excellent post, Sirius lies close to the rooftops from my garden and I will have to take a trip to a site with a better horizon if I am to try this. I may run out of time this year ......

It is only visible here for about an hour or so in a patch of open sky between my neighbours house and some large chestnut trees. I can prolong my "window" of viewing a little by gradually moving the scope a few feet but that's about it.

Luckily, when it is clear of the neighbours house, it lies over a school and some open countryside so is not affected by central heating plumes too much.

 

 

Edited February 4, 2021 by John

[Nik271]

I failed with Sirius B last night. The seeing started excellent before 8pm: I could see the E and F stars in the Trapezium with my Skymax 180 at x135. Sadly while I was waiting for Sirius to get higher the seeing gradually got worse, the stars airy discs started to bloat, then it got cloudy and rain arrived at 10pm. I had high hopes but it was just not to be a Pup night.

As a consolation I saw the triple stars of 40 Eridani for the first time (will write a separate post about it), so not feeling too bad about it

 

Nikolay

Edited February 4, 2021 by Nik271
corrected the Trapezium star names

[John]

1 hour ago, Nik271 said:

I failed with Sirius B last night. The seeing started excellent before 8pm: I could see the E and F stars in the Trapezium with my Skymax 180 at x135. Sadly while I was waiting for Sirius to get higher the seeing gradually got worse, the stars airy discs started to bloat, then it got cloudy and rain arrived at 10pm. I had high hopes but it was just not to be a Pup night.

As a consolation I saw the triple stars of 40 Eridani for the first time (will write a separate post about it), so not feeling too bad about it

 

Nikolay

I'm sure you will get it on another occasion Nikolay.

I can't recall observing 40 Eridani so I will read your report and have a look for it next time I am out.

Last night I found Pi Arietis near Mars and that turned out to be a nice uneven brightness triple star.

 

[Nik271]

15 minutes ago, John said:

I'm sure you will get it on another occasion Nikolay.

I can't recall observing 40 Eridani so I will read your report and have a look for it next time I am out.

Last night I found Pi Arietis near Mars and that turned out to be a nice uneven brightness triple star.

 

Thanks for the suggestion! It looks a challenging triple, but thankfully higher up in the sky, I will give it a try next time the sky is clear.

40 Eridani has a long thread in the observing section, I just added my observation. 

[JeremyS]

Last evening it was minus 6 deg C, but the seeing was generally very stable. It got the Tak TSA 120 out before dusk and got on with variable star work in the observatory until 21.30. Turning Tessa towards Rigel, I noticed how stable the seeing was, with a huge split of the secondary and with text diffraction rings.
 

Surely this had to be the night for Sirius and the Pup? I’ve tried for decades without success, but only a few times this season with the TSA (which I got last Spring).

 

Well seeing wasn’t quite so good down at the altitude of Sirius. Using the Vixen HR 3.4 (x265), I could see the Pup about 2/3 of the time right on the edge of the primary’s “skirts” (I think John used that expression and it’s perfect!). Switching to the  Vixen HR 2.4 (x 375) helped a bit. 
 

I looked at some other objects for a while and came back to Sirius at 22.30. With the HR 2.4 the Pup was visible most of the time.

 

Edited February 11, 2021 by JeremyS

[John]

32 minutes ago, JeremyS said:

Last evening it was minus 6 deg C, but the seeing was generally very stable. It got the Tak TSA 120 out before dusk and got on with variable star work in the observatory until 21.30. Turning Tessa towards Rigel, I noticed how stable the seeing was, with a huge split of the secondary and with text diffraction rings.
 

Surely this had to be the night for Sirius and the Pup? I’ve tried for decades without success, but only a few times this season with the TSA (which I got last Spring).

 

Well seeing wasn’t quite so good down at the altitude of Sirius. Using the Vixen HR 3.4 (x265), I could see the Pup about 2/3 of the time right on the edge of the primary’s “skirts” (I think John used that expression and it’s perfect!). Switching to the  Vixen HR 2.4 (x 375) helped a bit. 
 

I looked at some other objects for a while and came back to Sirius at 22.30. With the HR 2.4 the Pup was visible most of the time.

 

Excellent result Jeremy

I'll have a go with my ED120 when we get the next clear night - I've still not managed it with that scope, or the FC100-DL.

I know that there has been some skepticism expressed in some quarters (not SGL) on reported sightings of Sirius B with relatively small aperture instruments so I hope that is being overcome with these reports 

 

[Stu]

Well done @JeremyS. I tried with the 8” f8 last night, failed again! 🤪🤪

[Alan White]

Well done for going out at all last night @JeremyS, let alone the fine achievment.
I was busy giving a talk on The Moon at my club online last night,
I did venture out but just with the 10x50's and only for 20 mins before I froze, I admire your dedication.
 

[Stu]

3 minutes ago, Alan White said:

Well done for going out at all last night @JeremyS, let alone the fine achievment.
I was busy giving a talk on The Moon at my club online last night,
I did venture out but just with the 10x50's and only for 20 mins before I froze, I admire your dedication.
 

It was certainly chilly Alan 🤣

[Alan White]

@Stu The Artic fur hat, must be cold.
 

[Stu]

1 hour ago, Alan White said:

@Stu The Artic fur hat, must be cold.
 

Indeed! This is when it’s really cold...., out for my evening walk/scoot with the short person.

[Alan White]

23 minutes ago, Stu said:

Indeed! This is when it’s really cold...., out for my evening walk/scoot with the short person.

That's not cold, it's mearly chilly..... you have no ice on your lenses and no icicles on your nose sir!

[Barry-W-Fenner]

On 24/01/2021 at 13:05, John said:

Last night I was observing Sirius A and B again using my 12 inch dobsonian. The gap between the pair is currently about 11 arc seconds so about as wide as it gets during their 50 year orbit.

The actual distance between Sirius A and B varies between 8.2 and 31.5 AU so at their furthest apart a distance similar to that between the Sun and Neptune lies between them. At their closest approach the distance is a bit closer than the Sun - Saturn gap.

So the above gives a little idea of the scale of what we are observing over the 8.6 light years between us and the Sirius system.

With Sirius A being about twice the physical size of the Sun but 25x more luminous and Sirius B about the physical size of Venus, the system would make a fascinating spectacle from, say, .5 of a light year distance I would think

 

 

 

 

 

Very interesting read John. Puts it into perspective nicely!

[Whistlin Bob]

Thought I'd post a little well done (with a bit of envy!) to everyone who has seen it. I tried for ages on Wednesday night in my 8 inch dob. Tried 150x, 175x  and a slightly silly 300x but no dice. Rigel and e/f in the trapezium were all quite easy, so it was definitely the night for it, but couldn't get Sirius b. It was my only miss of the session though- lots of lovely views of other winter treats, so not so bad really!

Edited February 13, 2021 by Whistlin Bob
Typos

[Waddensky]

Had a (spoiler alert: unsuccessful) go at Sirius last night with my 8".

Warming up: Sigma Orionis lovely as always, Rigel was a clear split at 150x, with B suprisingly distant from A (I am used to estimating separations but the bright primary plays tricks on my estimation skills apparently ;)). The difference between the bright, scintillating A and the still, dim secondary right next to it was striking and very beautiful. Trapezium's E and F were nowhere to be found, strangely, but the surrounding nebulae were bright and contrast-rich. I can spend a whole night observing M42, it's so incredibly beautiful.

Then over to Sirius. The bright star was placed lower than Rigel of course, and quite some time before transit, but I figured I'd give it a try. With the separation of Rigel in mind, I scanned the area around the fiery primary. The effect of Sirius in the scope is quite different from Rigel. A large, boiling mess at 150-300x with quite a lot of atmospheric dispersion. Sometimes, I thought I saw a steady, tiny pinpoint in the glare following the primary as Sirius drifted through the FoV, but it wasn't there all the time and I really cannot say for sure that B was really there or my imagination (and my desire) created 'puppies' out of A's glare.

Tonight looks clear too, I'd really like to give it another go. It's a great challenge and very rewarding hunt!

[Nik271]

I had a similar experience as @Waddensky last night with 180 SW Mak:  The disc size of Sirius was well controlled most of the time and a couple of times I thought I saw a fleeting pinpoint north-east but it did not reoccur regularly enough to be sure.

I believe 250-300x is the right magnification to use in my scope: Sirius B is almost 9-th magnitude and being low in the sky atmospheric extinction will make it even dimmer. And magnification larger than 300 will make it just too dim. Magnification 250x should make 11'' separation appear as 44' in the eyepiece, so hopefully wide enough to separate from the glare. I'm still waiting for the perfect night to see the Pup🤞

 

Edited February 13, 2021 by Nik271