Observational Challenge Bucket List

[lunator]

Zeta Her in a 60mm seems a stretch. Out of interest what magnification do you use to split it? My formula implies on a night of excellent seeing you would need 120+ magnification. 

Cheers

Ian

[Emperor!Takahashi!]

9 minutes ago, lunator said:

Zeta Her in a 60mm seems a stretch. Out of interest what magnification do you use to split it? My formula implies on a night of excellent seeing you would need 120+ magnification. 

Cheers

Ian

I think Zet Her in 60mm is impossible 😁 I'm after Del Cyg in 60mm. My experience is that, even with 100mm, Zet Her is only subtly elongated... B just peeks over A. But in a larger scope, it's a beautiful uneven pair with B poised on the A's diffraction ring. 

[lunator]

2 minutes ago, Emperor!Takahashi! said:

I think Zet Her in 60mm is impossible 😁 I'm after Del Cyg in 60mm. My experience is that, even with 100mm, Zet Her is only subtly elongated... B just peeks over A. But in a larger scope, it's a beautiful uneven pair with B poised on the A's diffraction ring. 

I agree that Zeta Herc is probably impossible in a 60mm. It is always be wary of "averted imagination " 😀 😀

[Nik271]

I've detected the secondary of Zeta Herc in good seeing in my 100mm refractor as a bump on the first diffraction ring of the primary. Used x180 I think.

It looked somewhat like this, but in my seeing the bump was less obvious. I tried to simulate the extra thick diffraction ring in my scope, it has a little spherical aberration. (a Chinese FPL51 F7 doublet)

 

 

Delta Cygni in a perfect 60mm should look a bit like this:

 

 

Looks doable!

[Emperor!Takahashi!]

44 minutes ago, Nik271 said:

I've detected the secondary of Zeta Herc in good seeing in my 100mm refractor as a bump on the first diffraction ring of the primary. Used x180 I think.

It looked somewhat like this, but in my seeing the bump was less obvious. I tried to simulate the extra thick diffraction ring in my scope, it has a little spherical aberration. (a Chinese FPL51 F7 doublet)

 

 

Delta Cygni in a perfect 60mm should look a bit like this:

 

 

Looks doable!

The Zet Her picture that you posted looks like how I've seen it through a 5" scope. When I used a 4" scope, the bump wasn't as pronounced. And in the 180mm scope, the double was resolved/split... Quite a beautiful sight!

When I've observed Del Cyg, the B component doesn't appear as prominently as in the picture that you shared. I've most often observed it in a 4" scope, and it's a tiny little gem on the diffraction ring of the A star. Again: a beautiful sight. But even after multiple attempts with a Takahashi FOA-60Q, I haven't been able to resolve it. At times, I've thought, "There it is!" but those moments have been examples "averted imagination," as @lunator calls it 🙂 My experience tells me it isn't doable, but others say they've done it. So, I'll keep trying!

Edited June 17 by Emperor!Takahashi!

[Nik271]

I generate these with Aberrator and it does not show the difference in magnitudes very well. In Del Cyg there is a difference of 3.5 magnitudes so the secondary should be 16 times dimmer than the primary.

[John]

On 17/06/2024 at 11:48, Emperor!Takahashi! said:

I think Zet Her in 60mm is impossible 😁 I'm after Del Cyg in 60mm..... 

I'm going to try Delta Cyg with my 70mm refractor this evening. I'll see if it "goes" with that 🙂

I might even point it at Zeta Herc, but without too many expectations !

Edited June 18 by John

[John]

1 hour ago, John said:

I'm going to try Delta Cyg with my 70mm refractor this evening. I'll see if it "goes" with that 🙂

I might even point it at Zeta Herc, but without too many expectations !

Delta Cygni was split with the 70mm at around 150x. The secondary star was quite faint though. 

Izar and Epsilon Lyrae (both pairs) were also split and a little easier than Delta Cygni.

Zeta Herculis showed a suggestion of a "lump" on the correct side of the airy disk of the primary star. Nowhere near a split though, for me. It was like a slightly less distinct version of the 2nd Abberrator generated image that @Nik271 posted earlier in this thread. Seeing was probably around 6/10 maybe 7/10 at best ?

 

 

Edited June 18 by John

[IB20]

On 17/06/2024 at 17:02, Nik271 said:

I've detected the secondary of Zeta Herc in good seeing in my 100mm refractor as a bump on the first diffraction ring of the primary. Used x180 I think.

It looked somewhat like this, but in my seeing the bump was less obvious. I tried to simulate the extra thick diffraction ring in my scope, it has a little spherical aberration. (a Chinese FPL51 F7 doublet)

 

 

Delta Cygni in a perfect 60mm should look a bit like this:

 

 

Looks doable!

That Zeta Herc looks very similar to what I’ve observed in the 125mm! 

[Emperor!Takahashi!]

Well, folks, I did it. My "new" Takahashi FC-60 split Delta Cygni for me. That's after 2 years of trying to do it with an FOA-60Q. Life is interesting! It's a phenomenal little telescope.

That's one item off of the bucket list 😅