spotting Sirius B, another use with TV planetary filter

[allen g]

Now is a good period of time to attempt to view the little pup.  It is a tough one.  I read that it takes magnification and it best at twilight.  I tried with my 4" refractor with my 2.5 nagler (216x) to no avail. Then tried to barlow (2x) it which increased mag 432. Well Sirus was much too bright to see the pup.  Well why not experiment with a filter and tried the TV planetary because it was at my fingertips.  Well it worked in terms of the goal.  First, the color shifted to a blue/green.  Second, Sirius A was not in focus.  Third, Sirius B was perfectly seen.  I intend to try with other filters to see the effect.    

[alan potts]

Allen,

It is all about conditions for me. You need a very good stable sky best when Sirius has little in the way of scintillation. A couple of years back we had a period of weather where I could split it almost every night with the 115mm APO using about X90-X120, even less one night, never more, for me you need to have control of the airy disc of the star. Last year I only split it twice I recall and this year only once, the scopes and eyepieces are the same.

Oddly I still have yet to split this with my LX 12 inch having tried 8 years, which to me means aperture counts for little.

Alan

[John]

Interesting report Allen.

I did try the TV Planetary filter on Sirus while I had it but found it removed my ability to split the star rather than making it easier. Maybe I had a duff filter - pink tints and now this - mine just did not cut it

I'll try and have a peek through another one at the SGL star party next week and see if the effects are the same as the one I had or different. TV's quality control is usually top notch though.

Mint you, yourself and Alan are at lower lattitudes that I am so Sirius is higher above the horizon. That must help.

[alan potts]

John,

It most certainly does make a difference that extra 11-14 degres depending where one is in England. You may recall I was doing a test last year where I was trying to split the Pup using readings only when the Sirius was at UK values above the horizon, I have continued that at the end of last year and this. I have not seen the Pup under these constraints though my condition low down have been very poor most of the time, far too much atmostpheric activity.

Alan

[Hartmann]

Very interesting

I will try with my mak 127 when the weather improves next week.  In my location sirio reach 35 degrees  avobe the horizon.

[michael.h.f.wilkinson]

I much prefer using a narrowish-band red filter. Narrower band means atmospheric refraction is reduced, red means you are viewing in wavelengths less affected by seeing. The only filter I have ever used that gave me the Pup is red.

[rwilkey]

Hi Allen, very interesting, I have the TV Planetary and will try it out with my ES82 4.7mm when I get the chance, can always double with the ES 2x Extender which I also have.  Can't wait!