Nemesis vanquished....and other stuff 😉

[Stu]

I had no intention of observing tonight (last night now) as I thought it was going to be cloudy. However, on putting the rabbits away the skies looked ok, so I popped the dob out quickly to have a look at Jupiter. I started out just with my 7.2 to 21.5mm zoom for simpllicity, not expecting to need anything else, but Jupiter looked pretty crisp, so I brought out my orthos and the EQ platform to give me some tracking.

The 9mm gave a lovely view, and I could see the GRS coming around the corner onto the disk. I then noticed a large white circle or oval sitting on the SEB probably 2/3rds of a disk ahead of GRS. I wondered if it was Io transiting, but all four moons were strung out to one side of the planet so I assume it must have been what it looked like, a white oval. Seemed large and obvious so hopefully others saw it or captured it too.

Next up Saturn. Again this looked pretty crisp, I enjoyed the view at x128 with the Docter 12.5mm, small but razor sharp. Cassini clear too alot of the time. The shadow of the planet on its rings is getting more obvious to one side as we get further past opposition, and the C ring was also very clear, plus surface banding too. Titan and Rhea were visible, plus Iapetus but couldn't catch any others. Anyway, a very good view, as good as I've seen this apparition.

So enough of planets, what about the nemesis this madman speaks of?

Well, next up, I had a quick look at Pi Aquilae and it was a clear split with stable views, so onto said nemesis which is Zeta Herc. It still wasn't that dark and Hercules was tricky to identify at first, but once I had found Zeta I needed to remove the weight from the bottom of the scope as it was out of balance looking that high in the sky. I think I started with the 9mm BGO, played around with the 7 and 5, aswell as the Nag Zoom at up to x533 (🤣) but settled on the 5mm at x320 as best. I needed to pin the focus down very tightly, which is not so easy with the single speed focuser I currently have on this scope, but once done, as the seeing came and went, there it was! In the patches of good to excellent seeing it was very clear, two unequal disks, the secondary clear of the first diffraction ring. I checked Skysafari and the position was bang on so I'm pleased to say I've finally nailed this one after years of trying. When the seeing was off there was no hope, it just went back to  the mushy blob I'm used to.

Many thanks to @chiltonstar who has been my Zeta Herc mentor, offering advice and encouragement for quite some time! This scope has proved its worth, showing me something that all other scopes I've had have failed to achieve.

Nice little session, sorry for the long report!

[Rob Sellent]

Sounds a great evening, Stu and thanks for the write up. Would you say Zeta Herc was dependant as much on aperture as seeing, or do you think a smaller but potentially 'tidier' frac could also make this split?

[DirkSteele]

Nicely done.

[Demonperformer]

Great result, Stu.

Sometimes nights that start as 'is it worth bothering?' can produce gems like this. So I guess the answer should always be 'yes' ...

[Stu]

5 hours ago, Rob Sellent said:

Sounds a great evening, Stu and thanks for the write up. Would you say Zeta Herc was dependant as much on aperture as seeing, or do you think a smaller but potentially 'tidier' frac could also make this split?

Rob, seeing seems to be hugely important for this one, same for many tight doubles, particularly uneven ones. I've tried on many other occasions without getting a sniff of it, but last night conditions were obviously good enough.

I'm sure it can be done with a smaller scope with excellent conditions; a good mak or refractor which, as you say would produce nice tight star images would be an option. I'm not sure what the limiting aperture would be though, perhaps @chiltonstar Chris can help here?

The 8" f8 I'm using has high quality optics and a very small secondary obstruction and so it performs somewhat like a 6" apo refractor although it does obviously still show diffraction spikes on brighter stars and planets. It certainly worked for me last night!

[Saganite]

Congratulations Stu.

[Stu]

Welcome to the forum by the way @Rob Sellent 

[chiltonstar]

39 minutes ago, Stu said:

 

I'm sure it can be done with a smaller scope with excellent conditions; a good mak or refractor which, as you say would produce nice tight star images would be an option. I'm not sure what the limiting aperture would be though, perhaps @chiltonstar Chris can help here?

The 8" f8 I'm using has high quality optics and a very small secondary obstruction and so it performs somewhat like a 6" apo refractor although it does obviously still show diffraction spikes on brighter stars and planets. It certainly worked for me last night!

Great Stuff Stu! What a fantastic scope by the sound of it!

I've certainly split it with my 127 mak (true aperture 119mm) - smaller than this the secondary will merge with the diff ring of the primary I imagine, but maybe still visible in nights of exceptional seeing. This is a stacked image of Zeta Her with my 127 Mak, together with a simulation using Aberrator for 119mm aperture:-

Chris

 

 

[Rob Sellent]

Thanks for getting back Stu. It's been cloudy here the last few evenings but the next chance I get, I'm going to take up your own adventure and see how I do with Zeta Her. No doubt I will fail spectacularly because I don't have much aperture and my aging eyesight is rubbish 😀

Also nice to hear about your 8" f8. That really must be a lovely scope and rather unique. I mean, I've seen 8" f5s and even an f6 but never an f8. It's a real shame these types of OTAs are no longer in production. In terms of resolution, I imagine it'll out perform most 4"/5" ed or apos and in terms of contrast must also give the more exquisite glass types a run for their money. 

[Littleguy80]

Congrats on Zeta Herc, Stu. It’s those challenging targets that keep us coming back! I’m curious about the white oval on Jupiter. Do you know what it could be?

[Stu]

Thanks Rob. It's certainly a nice challenge, give Pi Aquilae a shot before hand, it's similar separation but more equal brightness so a fair bit easier.

The 8" f8 is a lovely scope, one of those rare bargains where you get alot of performance for not alot of cash (bought used of course!). The downside is a long tube and being a little unwieldy but it seems to be worth while persisting. I shall try to crack Sirius B this winter! Picture attached for you.

What scope do you have?

 

[Stu]

26 minutes ago, Littleguy80 said:

Congrats on Zeta Herc, Stu. It’s those challenging targets that keep us coming back! I’m curious about the white oval on Jupiter. Do you know what it could be?

Thanks Neil, indeed it is! I have some more confidence that the Pup may be within reach now finally!

I'm really not sure about the white oval, except to say it looked like, well a white oval 🤣. It seemed quite large, filling most of the SEB although it is not that wide at that point. It was definitely there, and caught me eye before the GRS did actually (GRS was right on the the limb when I first spotted it). I'll have to have a think about when it might next be centre disk. If the rotation is 10 hours then the position gets worse before it gets better I think.

[Rob Sellent]

Aye, I imagine on windy nights the 8" f8 may be a little troublesome but on these stiller summer evenings it must be quite a joy. Thank you for the heads up about Pi Aquilae. I've noted the star down in my notebook and will certainly check it out the next clear evening I get. I have a small TV 3" frac for general dash out and grab a view and a larger SW 12" dob. To be honest, these days I'm using the 3" a whole lot more. I've fallen in love so much with this little gem - its robust build and quality optics - that I'm seriously contemplating getting a little larger 4" (something like a secondhand FL102 or FC100). 

Thanks again for the reply and the cracking photo.  

[chiltonstar]

1 hour ago, Rob Sellent said:

 

Also nice to hear about your 8" f8. That really must be a lovely scope and rather unique. I mean, I've seen 8" f5s and even an f6 but never an f8. It's a real shame these types of OTAs are no longer in production. In terms of resolution, I imagine it'll out perform most 4"/5" ed or apos and in terms of contrast must also give the more exquisite glass types a run for their money. 

I imagine OOUK might well be prepared to do a production run of 8" f8 tubes if they thought there was a market - for example ten of us signing up to put in an order???

Chris

[Peter Drew]

I have a couple of 8" F8 OTA's and a 12" F8.5. The two 8" have OOUK optics, one quality standard not known and the other 1/20 wave claimed. The latter was mounted on a Fullerscopes Mk IV mount a few years ago when Jupiter was better placed and certainly gave excellent views.

[Mark at Beaufort]

Fantastic stuff Stu - I have still not split Zeta Hercules despite using many different scopes. I thought I might crack it with my 180mm Mak/Cass but unfortunately not. Clearly I must persevere.

[Stu]

1 hour ago, Rob Sellent said:

Aye, I imagine on windy nights the 8" f8 may be a little troublesome but on these stiller summer evenings it must be quite a joy. Thank you for the heads up about Pi Aquilae. I've noted the star down in my notebook and will certainly check it out the next clear evening I get. I have a small TV 3" frac for general dash out and grab a view and a larger SW 12" dob. To be honest, these days I'm using the 3" a whole lot more. I've fallen in love so much with this little gem - its robust build and quality optics - that I'm seriously contemplating getting a little larger 4" (something like a secondhand FL102 or FC100). 

Thanks again for the reply and the cracking photo.  

Is that a TV76 Rob? Very nice scopes. It may well manage Pi Aquilae but suspect it would struggle with Zeta Herc. PI Aq splits quite easily with my FC100 though.

I share your love of small refractors having had many over the years. 

Izar is another nice one in a smallish apo refractor if you haven't tried it.

 

[Stu]

2 minutes ago, Mark at Beaufort said:

Fantastic stuff Stu - I have still not split Zeta Hercules despite using many different scopes. I thought I might crack it with my 180mm Mak/Cass but unfortunately not. Clearly I must persevere.

Thanks Mark. I was delighted to get it finally I must say. I did a little jig for joy in the twilight which I hope no one saw

Seeing seems to be the main factor, plus the right scope properly cooled and collimated. I didn't manage it with the Intes 7", and I must say the stars shapes are significantly better in the 8" newt, I'm sure just because it is so much easier to cool.

I have seen it once before I think, in Gavin's TEC160 but that doesn't count; not my own scope and it's almost cheating to use something that good

I should try the Mewlon to see if that can manage it too, maybe more difficult due to the larger secondary obstruction.

[Mark at Beaufort]

@Stu- whilst checking through my computer files I noticed that I had a diagram of Zeta Hercules which I attach below. I am assuming this is the view through a reflector and it looks like a good time to view this pair looking at the dates.

[Stu]

2 minutes ago, Mark at Beaufort said:

@Stu- whilst checking through my computer files I noticed that I had a diagram of Zeta Hercules which I attach below. I am assuming this is the view through a reflector and it looks like a good time to view this pair looking at the dates.

Thanks Mark. Yes it does look to be a good time got this one. I'm sure the 180 mak should be capable of it, particularly if Chris can see it in his 127 but I never had any luck with my maks.....

[John]

Great report Stu and congratulations on that tricky little blighter - zeta hercules !

It does need good, steady seeing conditions and being high in the sky helps as well.

I have got it with my FC-100DL, ED120 and TMB/LZOS 130 fracs but it's very challenging in all of them, especially with the FC-100DL when it's intermittant at best.

 

[Stu]

39 minutes ago, John said:

Great report Stu and congratulations on that tricky little blighter - zeta hercules !

It does need good, steady seeing conditions and being high in the sky helps as well.

I have got it with my FC-100DL, ED120 and TMB/LZOS 130 fracs but it's very challenging in all of them, especially with the FC-100DL when it's intermittant at best.

 

Thanks John. Now I know what I'm looking for, it may be that it is easier in other scopes. Pi Aquilae is quite straight forward in the FC-100DC so Zeta Herc might be worth a try while it is up so high. I'm sure the DL is just that little bit better at the limits though, and I suspect your seeing is probably better than mine if only from fewer planes flying over head constantly!

[John]

29 minutes ago, Stu said:

.... Now I know what I'm looking for, it may be that it is easier in other scopes......

That is so often the case with many challenging astro targets isn't it ?

[Geoff Barnes]

Great stuff Stu, now you've given me a new challenge to go for!

I have to say I'm not too confident on splitting this one though from here, Zeta Hercules only just gets above my horizon at this time of year, slightly ahead of Lyra, and I find the Double Double incredibly hard to split being so low down in the murk and they are an easier split than Z H.

Next time I get a clear night with steady seeing I'll give it my best shot with the 12 inch Dob, wish me luck!  

[chiltonstar]

10 hours ago, Mark at Beaufort said:

Fantastic stuff Stu - I have still not split Zeta Hercules despite using many different scopes. I thought I might crack it with my 180mm Mak/Cass but unfortunately not. Clearly I must persevere.

I would say I've found it a lot easier with my 180 Mak than with my smaller scopes. I've not imaged it with the 180 Mak yet, but a simulation for different apertures shows how much better it is resolved at 180mm aperture - this closely matches the visual impression.

Chris