13 replies to this topic

[Urban Uraniborg]

After many attempts with hundreds of lesser images…the pup. 
I was not able to see Sirius B through the shine of A. This image is cropped/zoomed in. 
 

take with:

 

telescope 

10” f/10 SCT   Meade 2120

5xBarlow        Angeleyes

15mm ep        Celestron

Magnification   847x

 

camera

app NightCap on iPhone SE(2018)

ISO 3250

exposure 4”

[Urban Uraniborg]

Sirius A and B

Attached Thumbnails

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[havasman]

I am curious whether with 11.3+ arc" current separation (near max) you really need a camera to see both components when you have 10" aperture. It has been some years since they presented a particularly difficult visual observation.

 

reference  -  https://www.stelledo...?iddoppia=27936

Edited by havasman, 13 November 2023 - 03:29 PM.

[Urban Uraniborg]

Great reference! 
Working with wet winters and Sirius low in the light dome of Bortle 8 it’s a challenge, but I will keep trying or eventually get my 10” out to a dry Bortle 3..?

 

Review original image I made an error on ISO and exposure time. 
 

Correction:

 

ISO  1760

Exposure  10 seconds 

[Adam Long]

I am curious whether with 11.3+ arc" current separation (near max) you really need a camera to see both components when you have 10" aperture. It has been some years since they presented a particularly difficult visual observation.

 

reference  -  https://www.stelledo...?iddoppia=27936

The difficulty increases with latitude. Took me about three years in the Uk, to get good enough seeing so low in the sky. Sirius culminates at less than 20 degrees here. 

[weis14]

Always great to learn of another Sirius B observation.  It is a tricky object to image, I'm sure, due to the need to have absolutely perfect focus and high magnification.

 

Right now, I think it is an easier target visually than photographically.  Last year, I saw Sirius B from 44 degrees N with my 92mm Astro-Physics Stowaway at 245x.  I posted an observing report on CN here.  It isn't a particularly close spit, so a smaller scope could probably do it if it had tight enough stars.  I wonder if a really good 60mm refractor could do it at lower latitudes.  I don't own anything smaller than the Stowaway, and I'm stuck up here in the north, so I've never tried.  

[Urban Uraniborg]

Sirius climbs to 27° altitude here @ 45°N  high enough to catch it between the trees but not enough to get out of the light dome. 
I shall give lower magnification a try.  Thanks 

[weis14]

Sirius climbs to 27° altitude here @ 45°N  high enough to catch it between the trees but not enough to get out of the light dome. 
I shall give lower magnification a try.  Thanks 

I had similar issues with a light dome to the south and Sirius never getting very high in the sky.  I actually think that it might be easier to catch Sirius B in the late twilight and I intend to try this in the spring.  The reason for this is that the real difficulty of this split is all the extra light from Sirius A. I'm thinking that the brighter background in twilight might help, but I'm not sure if the gains from less light scatter from Sirius A will be outweighed by the increased difficulty of picking Sirius B out from the brighter sky.

 

Keep trying!  I really consider it an accomplishment for us northern observers due to the low position of Sirius in the sky and poor seeing associated with winter skies at our latitudes.

[C. Evangelista]

It is no problem here at 49° to split Sirius at 50x to 200x when seeing is Pickering 7-9 (often here), albeit using a splendid apo with 4" to 5" aperture :-).
Just use low magnification...!

[ZX12]

At 42 degrees Latitude I often split Sirius A/B depending on the aperture and conditions. I prefer lower powers from 80x-120x so that B shows up as a perfect sharp point rather than a dot.

 

Even with a good quality 100mm refractor it can be a challenge most nights.

 

I've had much better results with a 130mm during good seeing and transparency. It will pop in and out of view with many false sightings in between due to the scintillation of A.

 

My 160 has been the most consistent refractor at delivering a solid confirmation of seeing the B component.

 

With a C14 SCT, it's easy when seeing is decent, and is still bright enough that it's very visible with a binoviewer.

 

Here is a photo from the 14" using a Canon 60Da set at ISO800 and a 1" exposure. B was also visible on the Liveview screen while I was trying to achieve focus.

 

See photo.

 

Mike

 

Attached Thumbnails

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[Nucleophile]

Nice capture!

 

Question:  Was this prime focus or did you use an amplifying lens between camera and telescope?

Edited by Nucleophile, 17 December 2023 - 03:07 AM.

[ZX12]

This was at prime focus with the 14". Sirius was at its high point and conditions were excellent.

 

This particular C14 is quite a performer. I spend most of my double star observing time with refractors, but have to say I have never seen an SCT that is as sharp optically combined with not being plagued by thermal currents with its carbon fiber tube.

 

Mike

[Nucleophile]

Thanks, Mike.  Sounds like a wonderful instrument.

[c2m2t]

Hi ZX12!

That is a remarkable capture...inspires me to give it another go. When I am done with M 38, Sirius will be nicely waiting. I have a observing friend that brought his 14" Celestron SCT to our annual Messier Marathon. The view of M 13 through that scope is something I will never forget!

 

Cheers, Chris.