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Sirius B with 4" Mak

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#1 fcathell

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Posted 04 February 2018 - 11:41 AM

I managed to finally catch Sirius B with a 4" (102 mm) Apex Mak last night when Sirius A was at its zenith.  There was still some turbulence but I got a glimpse of it several times when seeing settled down. I knew the position angle and that really helped.  Needless to say, it was not easy in the 4" but certainly rewarding.

 

Frank

Tucson


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#2 Astrojensen

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Posted 04 February 2018 - 12:02 PM

Nice catch! Can you elaborate a little on the details of the observation, like magnification, eyepiece, diagonal, etc.?

 

 

Clear skies!
Thomas, Denmark


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#3 fcathell

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Posted 04 February 2018 - 12:34 PM

Thomas - I was using a 6 mm Orion "Expanse" eyepiece which gives 216X. Diagonal was a good quality Lumicon prism diagonal. Scope was on an old Celestron CG4 with a homemade stepper drive. I have been trying for several evenings now and last night the turbulence was minimal when Sirius got to max elevation. There were brief moments of steady seeing when the scintillation minimized and you could see Sirius B "peep" through. I have observed it before several times in a C-8 and larger instruments but have never been successful with a 4 inch scope. I tried higher and lower magnification but it was harder if not impossible to detect reliably.  It's position (angle) is just slightly north of due east from Sirius A.

 

Frank


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#4 Astrojensen

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Posted 04 February 2018 - 12:43 PM

Thanks! Details like that are important to get a "feel" of the observation, to see it in one's mind and to compare it with one's own observations. I recently observed it myself, with a 5" achromat, but much lower magnifications. 

 

 

Clear skies!
Thomas, Denmark


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#5 fcathell

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Posted 04 February 2018 - 02:21 PM

I remember experimenting with my old C8 many years ago (early 80s) when Sirius B was again close to aphelion.  I was mainly observing at the San Diego AA site in the high desert east of San Diego.  I found you could take a straight piece of coat hanger wire and place it in front of the C8's corrector to form a diffraction spike in the image that would tend to "channel" the diffraction away from the airy disk and along the spike.  This actually improved the ability to see Sirius B in some cases.  I need to try that experiment with my 4" Mak. 

 

Frank



#6 Kon Dealer

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Posted 09 February 2018 - 03:36 PM

Tried and failed on multiple occasions with multiple scopes 90 to 200mm.

Trouble is at 52 North, Sirius barely gets above the horizon frown.gif


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#7 fcathell

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Posted 09 February 2018 - 04:29 PM

I tried it again last night with the 4" Mak and the C8.  No luck at all in the Mak and a struggle in the C8.  Just too much scintillation in the primary.  It really wipes out Sirius B most of the time.

 

FC



#8 fcathell

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Posted 09 February 2018 - 11:45 PM

Success again tonight on Sirius B with the 4" Apex Mak and 6mm eyepiece. Turbulence was pretty minimal tonight with Sirius at max altitude, and I found that by placing a piece of straight coat hanger wire horizontally in front of the Mak's corrector actually helped a bit by "channeling" the diffraction along the induced diffraction spike. Also checked out Hind's Crimson carbon star too. Nice night here in Tucson.  Had a thick flannel coat on. M31 was naked eye.

 

Frank



#9 barbie

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Posted 10 February 2018 - 12:23 AM

I've seen sirius B as well as Antares' companion in a 4 inch F15 refractor under excellent seeing conditions.  This happened only once in my 50 years of observing from N.E. Ohio.


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#10 Astrojensen

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Posted 10 February 2018 - 01:24 AM

Tried and failed on multiple occasions with multiple scopes 90 to 200mm.

Trouble is at 52 North, Sirius barely gets above the horizon frown.gif

I'm at 55°N and I've seen Sirius B twice, so it can be done. 

 

 

Clear skies!
Thomas, Denmark



#11 cildastun

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Posted 10 February 2018 - 03:20 AM

 

Tried and failed on multiple occasions with multiple scopes 90 to 200mm.

Trouble is at 52 North, Sirius barely gets above the horizon frown.gif

I'm at 55°N and I've seen Sirius B twice, so it can be done. 

 

 

Clear skies!
Thomas, Denmark

 

I'm at 52 North and agree it can be done. I get best results with my grab 'n go (5" Mak with Vixen Porta2) moved to the middle of a large field, with a sight line across grassland, thus avoiding the thermal problems if I view such a low target near to dwellings or roadways etc. 

 

Chris




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