First look at Jupiter with FS128

[F15Rules]

Last night, just 3 and a half weeks after acquiring my dream scope, I had enough of a clear sky to get a short proper look at Jupiter.

If this sounds a bit of an anti climax, it's not a criticism of the scope at all, but of the conditions. Having moved a couple of months ago to Linconlshire, about 20  miles from the east coast, and with no large towns within 20 miles, the skies are definitely  a lot darker here than where I was before (about 12 miles west of Leicester, and surrounded by a ring of large towns and cities, Leiester, Coventry, Nottingham, Tamworth, Hinckley, Nuneaton, Birmingham connurbation etc etc). The nights are really not getting black dark now though, as summer approaches.

Since we moved here, the weather has either been thick cloud at night (at the time when the West and Scotland were having great clear skies), or the seeing has been awful. Or the Moon has got in the way, near full phase. Or a combination..

Anyway, last night was a bit better, ie it was pretty clear, no moon when I viewed, and I had got the scope out for an hour and a half to cool - one thing I have learned with bigger 5" plus scopes is that they do take a while to really give of their best - although doublets like mine can give decent views after 30-45 minutes, I really think that it's over an hour till everything is cooled to optimum level. You might disagree with me though. As an aside here, I think this dawned on me when I had my last bigger frac, for a few months, the ED Pro 120 F7.5...( I had stupidly done a trade for my Vixen ED103s for the ED120 with a few extras with it, in my quest for a near 5" apo, and wanting to believe all the rave reviews about it).

I've gone on record as saying I was underwhelmed with both ED120s I owned.  In fact, with the last one, I was so disappointed with it on first couple of uses that I resolved to get the objective properly checked over by Es Reid, as I was worried I might sell on a "lemon" to someone else (they do seem to sell quickly, and are almost universally acclaimed on forums like this). Anyway, Es kindly and promptly put the lens on his bench for a whole day, and used a 4mm ortho to test the optics, giving x225, probably as high a power as you would normally go on planets even on a good night. Meanwhile, I was BITTERLY regretting having let my wonderful ED103s Vixen go..

The essence of Es' comments back to me were that he thought the lens was of superb quality: in response to my question to rate it out of ten, he said he would give it a 9 "since no lens is absolutely perfect"! He also stated that he would be delighted to own a scope with that lens in it! However, relieved though I was, I still didn't see the kind of views that I had hoped for in the next couple of sessions. I had firmly decided to sell on the scope, as I had committed quietly, but sincerely, to try to buy Tony's (t0nedude) Tak FS128, my long time dream scope. And then, just before the ED120 sold, I had one session outside, where the scope had been left outside for a good 90 minutes, in very good seeing, and I got a pretty amazing view of Jupiter - arguably as good as the best view I ever had in my beloved D&G 5" F15 achromat, a truly excellent optic. 

If I am totally honest, I never fell in love with the ED120, even with Es' report on the lens, although I could now sell it with a clear conscience. I did however determine to do all I could to buy Tony's FS128, and began a process of selling off pretty much all my astro gear to help towards raising the funds to buy it. The ED120 went to a member here, who has since emailed me to say how delighted he is with it..that's important to me, as I would expect to trust something I buy from someone else, so I like to sell on items only if I have confidence in their being fit for purpose.

Sorry for the long preamble: I think, for me, that it's all about how my observing has been in the last year or so, due to circumstances. This has meant that I have only been able to get short, 30-45 minute sessions for much of the time. I suspect that much of the time Jules' observing sessions may also be short? Anyway, where I live, I just don't think that is long enough for a bigger lens and tube to cool right down to optimum in the way that a good 4" frac does. My Vixen ED103s never took more than 30 minutes to give of it's best, so this was ideally suited for short sessions. I think that this partly explains why 4" scopes are so popular...they just "work" almost right away.

Now that I am hopefully getting much closer to retirement, I hope that I will be able to let the Tak cool for longer, I'm thinking an hour at least. It's a big (but lightweight) tube, and a 5" glass is a lot bigger and heavier than a 4", even in a doublet. 

I also think that local micro climates can play a part.. I am surrounded on 3 sides by low hills - in Lincolnshire!. I believe these may be creating a local micro climate which means that the seeing is affected by it. I really hope I'm wrong, but so far, and until last night, any attempt for a short glimpse of the sky via a scope has been blighted by ugly turbulence.

Last night I prepared well. I got the scope out and let her cool for a good 90 minutes. I made sure polar alignment was true enough to track, balanced the scope etc etc and also left my eyepieces out to cool (note: another useful hint for myself, I now leave my eyepieces out with the scope so they can cool properly too!)

My first couple of attempts to look through the FS128 were frankly disappointing: I saw some CA, purplish on one side, yellowish on the other side of Jupiter, and more light scatter than I had expected. But on these occasions I had literally tried to look through the scope after just 15-20 minutes outside. Last night things were much better: still not setting my heart alight, the seeing was clearly only middling at best, but almost no CA, and there were some steady moments in which I saw 5 bands very clearly, the bottom one effectively going right down to the pole of the planet, and the Great Red Spot showed real, visible colour. Over the 50 minutes or so the GRS moved clearly from my right to left as I watched the planet. The 4 main moons were clearly differing sized disks, not points of light. The banding didn't show much colour last night, but I could feel that there was a lot more detail trying to get through the soup of the atmosphere, if that makes sense.

I found that the best view came with the Tak LE 7.5mm at x138 and the 18mm with an Intes x2.25 barlow to give x130. I also had a nice view with the Pentax XL 10.5mm with a x1.6 barlow nosepiece, this gave x158, but really and truly the x138 seemed to give the best view last night. I also did a star test on Arcturus and that was fine, very similar images inside and outside of focus but with still quite a bit of turbulence. Have you been finding the seeing is poor for much of the time lately, or am I just unlucky?

I'm still very much finding my feet with the actual scope. To be honest, I think it's beautiful to look at, even if it had no lens in it! How sad is that? But I have the mount now as I want it, the RA drive works beautifully and holds the image centered for ages with hardly any adjustment, the polar scope (illuminated) is superb, the finder (illuminated) is superb, (wish it was RACI though), and the stability of the mount on the bigger tripod is great. So all I need now is some half decent seeing, and I look forward to seeing what this lovely instrument can do on many different targets.

Clear (and steady) skies to all

Dave

 

[nightfisher]

Best if i dont comment on the parts where i am mentioned, hope the Tak grows on you some more and that you get better views with time

[Saganite]

Hi Dave,

Plenty of times I have wondered whether the effort I have made to mount Andromeda as she should be, was worthwhile because I was  not seeing what I know this scope can deliver, and then the session comes when, you realize it was definitely worth it. Sadly that doesn't happen all that often, but you can at least know that  when it does  you have one of the very best tools at your disposal to take advantage of it.

[John]

Very interesting, open and honest report Dave

The seeing has been a bit "up and down" here over the past couple of weeks.

I'm still finding my way with my "dream scopes" as well

What they have taught me is just how good my old ED120 and 12" dob actually are

 

[cotterless45]

I was thinking the same about an honest report ! Good to hear of the limitations of sky and short cutting preparation

. The skies have generally been poor this year. The Jet Stream is all over us sometimes, giving poor seeing. This and the bouts of high pressure haven't helped. There have very few magic nights of long quiet sky, here's hoping !

Nick.

[GavStar]

Excellent report Dave. Interesting point about difference in cooling between a 4 inch and 5 inch which I'm needing to get my head around at the moment. Certainly I've noticed the views on my 5 inch scopes are much more satisfying at the end of the session to the start! The potential time of 90 mins to cool a 5 inch is my experience as well. Re Jupiter last night I found the best views were below 150x as well. 

[Alfian]

What a good report to read Dave, look forward to more, as I'm sure you do.

[mikeDnight]

That's a great write-up Dave. Its really interesting to hear your views about the ED120 and your love for your 103mm Vixen ED. There's a lot of truth in what you say about 4" aperture being so popular because they seem to work well with very little cool down time.

Jupiter for me this year hasn't been very good so far, while over the previous two years it was very pleasing. I'm convinced that were experiencing some pretty poor seeing lately, which hopefully means there are better times ahead. I loved my FS128 very much and deeply regret part exchanging it for the FS152, which was a monster by comparison. I found I used the 152 less due to it being more trouble to set up, though in reality, it may have been more of a psychological problem rather than a physical one. I suspect that after a few nights under good skies with your 128 you'll grow to love it. I have many happy memories with mine; so many in fact that its the only scope I'd so far consider over my superb FC100DC, which is just a dream performer. I hope you soon get along with it as id hate to have to buy it off you! 

Mike

 

[Stu]

Very honest review Dave, must be frustrating that things are not immediately ideal.

Given the seeing conditions which I have faced over the last few months, I have little doubt that this is the problem (after cooling is sorted obviously). My 4" regularly gives me views which rival anything else on most occasions. As a for instance, last night I used my C925. The initial views earlier on were very nice, but by around ten o'clock they were mushy. I reckon the Tak would have been better later on, although it does not show as much detail under good to excellent conditions.

So, patience is the key I reckon. I'm sure the scope is not going anywhere, so get to know its foibles and use it under some excellent skies and I'm sure you will be delighted.

[dweller25]

Hello Dave,

That's a fair assessment, here is my drawing using the FS128 from the 7th May 2017

Jupiter has given me some great views in the past but it is now relatively low and I live due north of Bury and Manchester, throw in the Jet stream and this is all I saw !!

 

[paulastro]

Many thanks for your post Dave, I found some of your experiences, regarding the seeing, mirror many of mine.

My Takahashi FC 100 DL had first light on April 4th last when I took it to mikeDnight (who has a DC version).  We were also joined for the evening by a friend of ours who is a very experienced visual observer and has his own excellent telescope review site - he was keen to evaluate the DL and DC together.  As it happened it was an excellent night, far exceeding any seeing I have had since.  Our guest cried out 'WOW' when he looked through the DL, stating that it was the best view of Jupiter he has seen through any four inch scope.  Of course, I kidded myself at the time that I'd often get views like we had that night through the DL.  Of course this has not been the case!  After nearly fifty years observing I should and do know better, but in my enthusiasm I was rather carried away by the occasion.

Since this night I've had some great views with the DL, but none anywhere near as good as the three of us experienced this first night.  And of course, the reason is the seeing.  The seeing I generally get is just no-where near as good.  Generally, using two Baader MK111 zooms in my binoviewer, on most nights the best results are using equivalent magnifications of between x150 to x180.  Of course, I have used much more mag at times, but these are the most useful most of the time.

The reason I'm relating this, is because when you have such a night of seeing with your FS128, I'm confident your smile will be as broad as mine was on April 4th.  You will then smile confidently when the seeing isn't so good, knowing full well when it cooperates your scope will once again produce the goods, being the same quality optic it was when you had your first eureka view.  Of course, I was lucky in that I had an exceptional night on the very first night of using the DL, so whenever the seeing is poor, I'm still happy and content with the scope, knowing that when the time comes it will perform as wonderfully as it can.

I predict that with time, patience and you've had your first eureka night, you will be a very happy bunny!

[Paz]

A very interesting read. One day, when I grow up, I'd like to try a quality refractor and see what all the fuss is about!

[YKSE]

A very nice honest first light, Dave. 

Planetary DOES need pretty good seeings to have a fair chance

[Pig]

Great report Dave,
I hope you get some good seeing conditions so you can experience the "wow factor"  from your scope, they do seem to be quite a rarity of late 

[Peter Drew]

The conventional wisdom of letting the telescope cool before expecting to use high powers is one that I subscribe to, and yet, and I'm sorry to keep on about this, but during my recent 2 weeks in Tenerife with some periods of oustanding seeing, my C8 which is kept in the apartment at around 25C all day performs immediately at high power when set up outside at around 19C, 200x-400x on Jupiter and 400x-800x on the Moon.??? I've also noticed that this is during the regular "golden Hour" which seems to be between sunset at 8.45pm and 10pm when presumably the temperature between the land and the nearby sea reaches equality. After that the seeing usually degrades to good.   

[F15Rules]

3 hours ago, mikeDnight said:

That's a great write-up Dave. Its really interesting to hear your views about the ED120 and your love for your 103mm Vixen ED. There's a lot of truth in what you say about 4" aperture being so popular because they seem to work well with very little cool down time.

Jupiter for me this year hasn't been very good so far, while over the previous two years it was very pleasing. I'm convinced that were experiencing some pretty poor seeing lately, which hopefully means there are better times ahead. I loved my FS128 very much and deeply regret part exchanging it for the FS152, which was a monster by comparison. I found I used the 152 less due to it being more trouble to set up, though in reality, it may have been more of a psychological problem rather than a physical one. I suspect that after a few nights under good skies with your 128 you'll grow to love it. I have many happy memories with mine; so many in fact that its the only scope I'd so far consider over my superb FC100DC, which is just a dream performer. I hope you soon get along with it as id hate to have to buy it off you! 

Mike

 

Thanks Mike ?. I've read with interest your many affectionate references to your FS128 and been inspired by them.

I hope I haven't given the impression I'm disappointed in the scope, I really am not..?.

I do see this as a long term scope, and it is very easy to move about for what is a pretty large but light tube. 

I think I am just impatient to get the best from her as soon as possible!

Dave

[RT65CB-SWL]

Nice report Dave.

I think you are correct in saying Lincolnshire has its own micro-climate. Nothing personal, but I blame the 'four queens' (the steelmills in Scunthorpe) for it. My father & step-mother live in a small but spread out village not far away. Where they live... the night skies are dark compared to what I am used to down here... down south. I do get the "Wow!" factor whenever I take my TeleVue Ranger with me.

[Davey-T]

Nice report Dave, having retired a while ago and been able to indulge in a bit of astro splurging I'm just hoping to get my monies worth before the inevitable happens 

Last night I set up the 152 and opened the eyepiece case nice and early hoping to catch the couple of hours of forecast sky and there it was, not a breath of wind beautifully clear and no dew until the clouds appeared on cue.

In the meantime the GRS was creeping around so I optimistically tried the 6mm Ethos and was treated to a lovely Jupiter despite being fairly low, with lots of detail so nothing ventured I tried the  6mm + 2X Powermate, X 300 ?  and in moments of steady seeing was treated to the best views of Jupiter for a long time.

It's only a Tecnosky not a Tak, no idea how it compares and Mike seems to prefer the 128 but for the price it gives pretty impressive Lunar views with very little CA and it's a manageable weight.

As mentioned by Peter just seemed to catch it at the right time and I was also viewing over the sea coincidentally.

We just need all the favourable conditions to coincide and get memorable views to keep us going for a few months until the next time 

Dave

[F15Rules]

2 hours ago, dweller25 said:

Hello Dave,

That's a fair assessment, here is my drawing using the FS128 from the 7th May 2017

Jupiter has given me some great views in the past but it is now relatively low and I live due north of Bury and Manchester, throw in the Jet stream and this is all I saw !!

 

Hi David

Yes, your drawing does approximate to what I saw last night, with the exception of the 3 small ovals, which I didn't see. Great drawing!

Dave

[Pondus]

In so many ways a truly interesting report, I`ve never looked through a high end refractor. The long cooling time surprises me, as a dob user I assumed cooling time of a frac  would be way short of an hour regardless of size and type.  

 

Rune

 

[F15Rules]

10 hours ago, Philip R said:

Nice report Dave.

I think you are correct in saying Lincolnshire has its own micro-climate. Nothing personal, but I blame the 'four queens' (the steelmills in Scunthorpe) for it. My father & step-mother live in a small but spread out village not far away. Where they live... the night skies are dark compared to what I am used to down here... down south. I do get the "Wow!" factor whenever I take my TeleVue Ranger with me.

Hi Phillip,

I'm confident that the steel mills are not a factor?. Lincolnshire is a very large county and I live almost 60 miles from Scunthorpe, in the opposite direction to the prevailing winds.. I don't doubt that they could affect nearby villages in the wind direction of the factories though.

I live much further south in the Wolds area, hence the "hills" ( with apologies to real "hills" everywhere?).

Dave

[Chris]

Hi Dave, thanks for the very sincere report, I'm sure you'll get a cracking night before you know it Yes it's all about cooling and seeing isn't it, but as said, it's good to know you have one of the best scopes out there then it all comes together  The big gun Tak 128 for when the seeing is good and you have the time, and the Moonraker for when the seeing is poorer and you don't have the time, hows that for a quality combo   

[chiltonstar]

A very thoughtful observation.

We've all been battling the seeing this year I think! Another factor to be borne in mind is the rate of cooling of the atmosphere (dT/dt) which has a worse effect on a larger scope than a small one, which reaches thermal equilibrium more quickly. Additionally, I find a huge difference between putting the scope on grass looking out across grass, compared with looking over concrete or roads, both of which have horrendous thermals. it will get better though when the evenings are warm and humid, and the air doesn't cool as much......

Chris

[F15Rules]

7 hours ago, chiltonstar said:

A very thoughtful observation.

We've all been battling the seeing this year I think! Another factor to be borne in mind is the rate of cooling of the atmosphere (dT/dt) which has a worse effect on a larger scope than a small one, which reaches thermal equilibrium more quickly. Additionally, I find a huge difference between putting the scope on grass looking out across grass, compared with looking over concrete or roads, both of which have horrendous thermals. it will get better though when the evenings are warm and humid, and the air doesn't cool as much......

Chris

Thanks Chris (both of you?). That's a good point about grass versus hardstanding..before moving I always observed on a tarmac drive..now from a lawn. Is that going to make a significant difference either way?

Dave

[chiltonstar]

35 minutes ago, F15Rules said:

Thanks Chris (both of you?). That's a good point about grass versus hardstanding..before moving I always observed on a tarmac drive..now from a lawn. Is that going to make a significant difference either way?

Dave

It is supposed to......and certainly does for me, particularly for viewing objects like Jupiter and Saturn at low altitudes. I also try to avoid the heat plumes above my neighbours' house, and downwind from my own if possible (not always), but as ever, it's a compromise.

Chris