Stu

As I understand it, the PowerMates and TeleExtenders maintain the eye relief of the eyepiece whereas Barlows extend it outwards. This can be useful for short focal length orthos for example, or annoying for long focal length plossls where the long eye relief can make eye positioning difficult.

I’ve used x2.5 PMs before and found them excellent. Barlows can be too though, I have a Zeiss Abbé Barlow and the quality is superb.

9 minutes ago, Flame Nebula said:

Hi Steve, 

I am dabbling with the dangerous idea of a gso newt on an AZEQ6. 😬. Decades ago I had a Dob and for the same reason as you, knew my next big scope needed to track planets at high mag. I have an ed80, hence the az-eq6 mount can be used for dso AP too. 

If you want/need tracking then perhaps consider and EQ platform. Quite a few of us use them; they are easy to setup and give around 45 mins to an hour of tracking.

I keep tagging him for this 🤣, but @Captain Scarlet uses a 12” newt in an AZ-EQ6 successfully so will be able to comment.

Orion Optics dobs are significantly lighter as they are aluminium rather than steel. Theoretically they can have better mirror quality if you spec the higher grade mirrors but I’ve not seen a side by side with a GSO scope to know whether this actually gives better results or not. They are a chunk of cash new, so buying used makes a lot of sense.

1 hour ago, niallk said:

I'm always amazed at how subtle structure resolves with the slight adjustment of focus.

Totally agree with this, for both Ha and White Light. A small fraction of a turn on the fine focus really makes the granulation pop in white light.

10 minutes ago, LDW1 said:

I am not so sure they even make a 2 speed for the Lunt 40/50  scopes ?

I saw this one linked to on one of the threads I read. No idea of it’s available or not. Looks a bit ungainly to me.

https://www.firstlightoptics.com/specialist-focusers-borg-tele-vue-lunt-gso-rc/feathertouch-125-dual-speed-focuser-for-lunt-ls50-solar-telescopes.html

Can’t beat a nice Feathertouch, and that looks really nice! Looks very neat and compact. I had wondered whether dual speed would be better but from a bit of reading it’s not necessary on these scopes, and actually the dual speed version looks a bit ungainly in comparison. Make sure to post an image of it fitted, and enjoy! 👍

2 hours ago, Highburymark said:

Agree that 60mm is too little for really satisfying WL detail Stu, but the 60mm PST mod sounds promising. Presumably you just swap over the etalon from your monster mod scope?
I still think 100mm is the sweet spot for white light in U.K. seeing - it’s the one thing I miss having moved to a TSA-120 from a 100DC. With the 120, I’d say 75% of sessions are compromised by seeing. But the other 25% certainly compensate. Marvellous views at 250x on very special occasions. Have you tried the wedge with your FS128 yet? 

Yep, probably needs a very good day to make it worthwhile, but useful as a very compact travel kit.

Simplistically yes, just need the back end from the other mod but I need to get the etalon at the right distance. It’s not just a case of measuring 600mm from the objective because of the CQ module, but I did find the focal point then the etalon needs to be 200mm ahead of that. Will give it a go at some point soon.

I have had a brief solar session with the FS128 but not in gods seeing, should be good anyway. I’ve also got a 120mm Celestron Omni XLT f8.3 which nearly went to Wookie65 but had a last minute reprieve so I’ll try that too.

Ludicrously enough, I also have a second 150mm f10 in the attic (don’t ask) which just needs a bit of fettling to get sorted. Might just try that for white light alongside The Beast! That would be a crazy setup for days of really good seeing!

Have been meaning to try this for a while, the CoolWedge in my FS-60Q.

I was concerned about heat build up in the Q module, probably unnecessarily but I rigged up a UV/IR cut filter ahead of this lens just for safe measure. Not needed with the Sun this low, but perhaps will help on a hot mid summer’s day.

Inwards focus is always a challenge I find with the 60mm, especially with the Wedge which has a long light path and Binoviewers on top of that. I played around with a few options, eventually removing the 2” ClickLock so I could attach the MaxBright IIs directly to the CoolWedge II, which has that option. I had to use a x2.6 GPC, but with 25mm eyepieces this resulted in a decent sized full disk view but with plenty of surrounding sky. Adding extension tubes allowed me to up this so only around 50% of the disk was visible, giving significantly higher mag.

Seeing was pretty ropey in the gaps between clouds, but still good enough to see the large AR which is disappearing around the limb now, plus plenty more of the smaller ones. Even 3597, 3594 and 3592 showed as small spots.

Granulation was pretty much invisible, just a hint of mottling over the surface, small aperture and poor seeing the culprits.

Anyway, nice to have the option of a very compact scope for travel. I did try the 76 DCU aswell, finding focus with the same setup and that showed the same mage scale but more resolution at a very similar magnification due to the virtually matched focal lengths; 570mm vs 600mm for the Q

I’m intrigued by the prospect of using the 60Q as a small PST mod for travel too; it is f10 which is ideal, I just need to source a Baader Ha filter to sit ahead of the CQ optics and see if I can reach focus. It may need a cut down rear tube but I’ll see what happens.

Some pics for reference.

1 hour ago, PatrickO said:

Those are wonderful sketches. Would be great if they were all gathered in one place 

Let me see what I can do. They may be somewhere already so I’ll post a link, otherwise we may be able to get them into a gallery.

It’s worth having a look through Mike73’s Sketches; he did a project to sketch all the Messier objects, all viewed from a dark site through 12” and 16” scopes. I thought there was a gallery or website with them hosted on but they seem to have lapsed, so have a look through this thread. I think I have them all saved so can post them up somewhere if that is easier?

1 hour ago, JeremyS said:

I seem to remember someone on here saying these aren’t too shabby, so thought I’d try

They’re ok I s’pose 😉

4 minutes ago, Littleguy80 said:

Though maybe the AZ75 will work for that purpose too? 

If you’ve got the ability to take a bit more weight then yes it would. A lot depends on the tripod too though, as you know.

1 hour ago, Cometeer said:

Twins! I highly recommend the K-Astec TB-80AS rings if you are looking for new ones. I mount a Vixen dovetail on one side, an arca swiss dovetail on another, and a finder clamp on the 3rd side. These are lighter than More Blue rings too.

They look nice, sourced directly from Japan?

I agree, the AZ75 engineering is in a different league to the Giro-WR, but to be fair, so is the price!

I’ve found the 75 to be hugely capable, and just like the 100 it does not need counterweights to stay smooth; the only reason to add a counterweight is to ensure the stability of the whole rig if you feel that is necessary. I’m thinking of switching my FC100 to the AZ75/Uni-28 and putting the FS-128 on the AZ-100/Planet. Currently I have the 150mm PST mod on the 100 simply as somewhere to keep it, but Mrs Stu is not overly happy about it being around so it may have to live upstairs.

Back to the point, the other thing that surprised me about the AZ75 was just how compact and lightweight it is compared with the 100, but with the same superb engineering.

3 minutes ago, The60mmKid said:

No beef, Stu! I'm a vegetarian! And especially not with you! You're one of my SGL faves!

But it's permissible to make a point with a certain degree of respectful adamance when it feels helpful, no? And maybe also with a certain playfulness? Although I admit that my attempts at humor usually fall flat... Respectful, playful disagreement isn't too beefy, I hope 🤞

In any case, no insult or injury intended. Please PM me if further communication on the matter would help.

Wishing you a good day ❤️

Good good. As my wife frequently says to me when I tell her I was joking about something, ‘I would work on that’ 🤪

Absolutely, friendly disagreement is fine and an essential part of the forum. I guess I just personally work on the basis of presenting opinions and letting the OP take all the info in and decide themselves. Much like when people ask for advice on which scope to buy, I prefer to see people discussing the pros and cons of scopes they think are suitable, rather than a ‘you must buy this because it’s what I’ve got and think is good’ type approach.

I will drop you a PM later, but all is good 👍 

6 minutes ago, The60mmKid said:

Of course it's his choice, but I'll respectfully repeat my opinion that adjusting the collimation isn't the best action to take at this point 👍 I doubt that my opinions are robbing him of free will ☺️

Another point worth mentioning is the inherent coma of the DK design. Stars have to be dead center in the FOV for the diffraction pattern to appear concentric. So, if a star is a little bit off to the side, it may appear as though the collimation is off.

There is a benign learning curve when using a Mewlon after refractors. I think it's most helpful to point out the possible variables first rather than, at this point, suggesting fixing collimation that may not need fixing.

I have used a Mewlon 210 for some time, so am well aware of the characteristics. I have already pointed out the need for a centred star and agreed with the need for a cooled scope. I have said that I don’t think the hairy stars are related to collimation but are likely cooling or seeing related. To get the best out of these scopes, they need to be bang on with collimation so that is certainly something well worth doing as David has verified, carefully and with research. I really don’t see what your beef is?

4 minutes ago, The60mmKid said:

Because it would be sad to make changes to the collimation if it isn't actually an issue 😭 That's why I think the thing to do would be to address the thermals and wait for good seeing. That may solve the hairy stars problem. And if the collimation is the problem, adjusting it would still require a thermally acclimated scope good seeing since a steady defocused star image with a clear diffraction pattern is needed for the job (assuming that's the method of collimation being used vs. an artificial star). So, in either case, I think it would be a mistake to touch those collimation screws right now.

Well it is Malcolm’s choice, and there are other ways of going about it such as an artificial star. Cooling is a problem we all face, and all deal with when collimating scopes. He has said the collimation looks slightly off, and that can have quite an impact on planetary detail. I don’t think it is the cause of the hairy stars as I said, but do think it is worth looking at, carefully as I’ve said. It is actually not as hard with these scopes as it seems.

14 minutes ago, The60mmKid said:

But wait until you have the thermals sorted and good seeing before adjusting the collimation! 

Why so sad?

I would agree that it is potentially a cooling/acclimatisation issue. I used to find the same with my 210. As for collimation, I think it is worth having a go. The screws are very tight, and should remain so; I just backed one off and took the tiny amount of slack up with whichever one needed adjusting. Very small adjustments, and keep everything tight and it should hold very well once done. Agreed about centring the star each time, that is essential for an accurate result.

I’ve yet to see in in over 20 years with a very wide variety of scopes! Hopefully at some point I will, in theory either the FS128 or 8” f8 should do the trick, but perhaps it’s just my eyes! ☹️

22 minutes ago, Icesheet said:

but I’m still surprised how compact the FC100 is there.

Yep, that’s why they are so popular I think; great optically and about the most compact and lightest, readily available 4” around.

Some more pics of the scopes packed down to show the comparison. When split, the 76 does feel quite a lot smaller and would go into a short case.

23 hours ago, Icesheet said:

Apologies for hijacking your thread somewhat @Mumia. Lovely set up you have and one I am looking at in the future. 
 

I recently sold my Tak FS-60 with reducer. I had a feeling I might end up regretting it so I kept the Q extender, visual adapters and FT 2015BCR that I never got round to putting on the FS-60. My thinking was I could buy the 76DCU objective in the future and have a 76DCUQ on the ‘cheap’. However, looking enviously at the photo of@Stu scopes, I am struck by how little there seems to be size wise between the 76Q and FC100. I also didn’t know the 2” FT’s were compatible with the FC100. I’m now wondering if it might be worthwhile skipping the 76 altogether and jumping to the FC100. What’s the thoughts on the improvement of the FC100 v 76DCUQ on planetary and lunar? Would I miss much on portability and cool down time between the two?

I have travelled with both, and there are pros and cons to each. The FC100DC will go in carry on baggage but this requires removal of the dew shield and focuser. This is fairly straightforward to do and I normally then put the dew shield over the OTA with some protection between them to avoid scratching.

I normally split the 76 in two which in itself takes up two parts of my travel case so the main benefit becomes the weight. You can also just remove the dew shield and put it over the OTA so it fits into the central section so that is more compact than the 100DC. Obviously it is thinner too so more can be packed around it.
 

For info, weights and lengths are as below including MoreBlue rings and dovetail:

FC-100DC   3.5kg   62.5cm

FC-76DCU  2.1kg    53.5cm

FS-60Q       1.95kg  42.5cm

EDIT these were with the lightweight focuser on the 76, which is not how I normally have it. With the LW on the 60, the weights are:

FC-76DCU  2.25kg

FS-60Q       1.8kg

The 100DC needs the focuser and dew shield to be removed in order to fit in my Airport accelerator case, the 76DCU just needs the dew shield to be removed and of course the 60Q fits in fully assembled.

The 2” FTs work very well with, and suit all these scopes in my opinion. I find the 2025 is better with its longer travel range.

In terms of performance, they follow theory in my view ie you can see the differences between 60, 76 and 100. I think the 100 definitely shows more detail on planets and the Moon, and splits tighter doubles. The 76DCU or Q are fantastic for their aperture, but I don’t think the Q addition enable it to beat the 100.

This seems to be diverting into an EQ vs Alt Az mount thread, so apologies for continuing in the same vein.

I enjoy EQ mounts, driven in RA for solar, lunar and planetary observing, situations where you are concentrating on one or two objects at high power and want a stable view in order to concentrate. An EQ for visual is, as Michael says, trivial to setup; plonk it down level, facing North with the latitude set correctly and away you go. I do not really enjoy them for star hopping as my brain doesn’t work in RA/Dec! Goto EQs are fine though, my GP-DX with SkySensor 2000pc controller works really well.

For star hopping I much prefer manual AltAz mounts as I find them easier and much more intuitive to use. Many targets are low or medium power too, so tracking is much less of an issue. Goto AltAz is also fine, especially if it is an AZ100 ☺️

1 minute ago, josefk said:

Is that 60Q, 76, 100 left to right @Stu or some other combination?

Exactly that, 60Q, 76DCU and 100DC, left to right.

The 60 has a lightweight 2025 FT, the others the standard 2025BCR, really makes them complete in my eyes.

Just as an aside, my CQ Extender normally lives on my FS-60, making it a Q as that’s where it makes most difference. I do love the 76Q configuration though. Comparison here, sorry if I’ve posted this one too much 😬