John

Just made my first split of Zeta Herculis this season now that it's risen above the conifers. Quite tight with 100mm aperture at 225x and 257x. Like seeing an old friend 🙂

1 hour ago, Spile said:

I assume there are no lock bolts on the primary mount of 12”?

The GSO primary cells do have locking bolts. They are a mixed blessing though because the cell components are made of quite thin metal and using the locking bolts can cause the cell containing the mirror to flex, which can itself alter the collimation.

Nice lunar views here tonight.

Interesting comparing the TOE 4mm, Nagler 2-4mm zoom, 4mm HD ortho and 3.5mm XW in my 100mm frac. No overall winner tonight but their presentation of the finer lunar features is subtly different. 

I was quite pleased, given the lunar illumination tonight, to catch some of the tiny craters that make up the Catena Davy crater chain. Fascinating to consider how such features might have been formed.

I can tell my other half that I have seen Susan with my scope tonight - that should be fun 😁

For me, getting a 10 inch and then a 12 inch dobsonian really was a game changer in the hobby. Far, far more so than my more recent acquisitions of top class 100mm and 130mm apo refractors.

I can't speak for others but for me the aperture opened up many more observing possibilities and has provided me with my best observing experiences.

You need to be able to handle, site and store such a scope of course. 

"Your Mileage May Vary" as the saying goes 🙂

33 minutes ago, Space Hopper said:

Crikey :   € 295 . 00 for a filter 😮

It would need to be excellent.

The TV Bandmate 2 Nebustar 2 inch is £299 now. It is really excellent though, by all accounts.

I use the Baader T2 Zeiss prism with my FC100-DL. This is the back end of the scope. This arrangement seems to suit all my various eyepieces. I use 1.25 inch eyepieces most of the time with this scope. There is a T2 15mm extension tube between the topside of the prism and the 1.25 inch click lock adapter which is not obvious in this photo:

Oops ! - I've just noticed that your Taks don't have the same focuser that mine does so the above might not be too much help. Apologies for missing that.

I agree with @Mr Spock that the primary cell collimation springs are weak and replacing them much improves the holding of collimation. I had the same issue with my Meade Lightbridge 12 inch which was also made by GSO.

It is frustrating that GSO have not addressed this issue - collimation is one of the main issues that folks are wary of with newtonian telescopes and the GSO weak springs problem has been discussed often for more than 15 years on astro forums such as SGL and Cloudynights 😒

41 minutes ago, bosun21 said:

I had both the SVbony UHC and OIII filters which I was relatively happy with until I borrowed the Astronomik UHC and OIII filters from a friend. The difference was apparent straight away with the surrounding sky being darker and the target brighter. Soon thereafter I sold both the SVbony filters and purchased both the Astronomiks. They are indeed more expensive but I learned with my eyepiece journey the old saying “buy cheap buy twice”. This definitely applied to me in this case.

That was the point that I was trying to make.

I have seen quite often people put off from using O-III or UHC filters though getting rather uninspiring results from less effective ones. When you use good ones which have an effective specification for visual use (which do tend to cost more 🙄) the impact can be significantly greater on receptive targets - like night and day really.

I'd love to try the APM zoom but I don't think that I'm prepared to buy it to do that. Happy to read others experiences of it though and an in-depth comparison with good fixed focal length alternatives plus the Baader zoom as a benchmark would be excellent 🙂

I invested in the Leica ASPH zoom a few years back plus a VIP barlow to extend it's range but somehow it didn't convince me to abandon my fixed FL eyepieces, hence my caution over this new(ish) zoom.

I think it will work but it won't necessarily be an indication of what a good visual O-III filter can do.

2 hours ago, JeremyS said:

Are you missing parts of “your” set, John?

I have the 21, 13, 8, 6 and 4.7 in the Ethos series. I did have the 17mm and 3.7mm for a while but they didn't get used much so they went to new homes. The one that I have not owned is the 10mm but, again, that's not a focal length that I find I reach for much.

1 minute ago, SuburbanMak said:

Thanks John - I’ll have another play with it, looked to me like the rubber section just unscrews without delivering much in the way of increased height, could entirely be user error! 

The topmost tapered part does just unscrew but that is not the eyecup adjustment. It is the whole top section of the eyepiece, the whole of the rubber coated part, that will turn and move either upwards or downwards. The travel is about 15-16mm taken from my XW 5mm.

Posted in error.

Nice report and a good haul of doubles 🙂

Last time I was out and about in that part of the sky I enjoyed Iota leonis (Σ 1536) below the lions belly. A tight uneven double that plays to the optical strengths of the Tak FC 100 and the TOE eyepieces.

Very nice report - I enjoyed reading it 🙂

As others have said, if you don't wear glasses then the top section of the XW eyepieces need to be well towards or at their highest positions to avoid eye positioning issues. If you wear glasses then the opposite is often the case.

At or around that focal length I currently have the XW 3.5mm along with a Nagler zoom 2-4mm and a TOE 4mm. The latter 2 have 10mm of eye relief and a 52/50 degree AFoV so might not quite tick all your boxes. 

The XW 3.5 mm ticks all of them and is optically right up there as well. That would be the one that I would recommend in your case. I'm sure that your Starfield 102 would handle the 204x magnification that a 3.5mm eyepiece delivers effectively as long as the seeing is decent.

29 minutes ago, Dave scutt said:

DPD delivered this today from @Saganite.

Now i could fit 1  or 2 more a push , wish i never sold the 6mm.

Thanks steve well packaged,  ive even got extra pluck foam for another case.

That's going to be "my" type of eyepiece set 🙂

The 6mm is superb. I love the 8mm as well, not that you want to hear that !

27 minutes ago, Highburymark said:

This is exactly what I need now - a pair of 1.25” 50/55mm plossls, though I have the excellent TV40s. Why? Because I have a solar Ha filter that needs as slow a light beam as possible to show surface detail well - so ideally I’d stick a 2x extender in front of the 3x barlow/extender built into the filter. Trouble is, that would still give me far too much magnification with my TV40s in a binoviewer. A pair of 55mms would be perfect - though not even I am demented enough to try two TV55s in a 2” binoviewer. 
Yet there may be a solution. I believe Russell Optics in Vermont does a 50mm 1.25” plossl. But I’m sure they would be extremely challenging with eye relief. Don’t know if Louis or Don have any experience with Russell, or even more unlikely, with such an unlikely eyepiece?

Apols for diverting the thread anyway….. I liked your story John

No problem Mark  - interesting challenge🙂

In the 1.25 inch fitting, 40mm plus focal length eyepieces are scarce. Vixen used to have a 45mm version of their "silvertop" range but they are quite hard to find singly, let alone as a pair. There was a Celestron 42mm Ultima (old, Japanese series) but that might not be long enough for your needs. 

35 minutes ago, Mandy D said:

I've spoken with the supplier who has told me the backlash can be adjusted out and is going to get me a manual for it from Synta. I guess backlash is inherent in any system with moving parts and the general idea would be to minimise it to the point where it no longer matters. Mine seems to have an awful lot in the azimuth gears. Are you using it purely for visual or are you doing imaging with it?

I have had a Skytee II for quite a few years now. I have managed to adjust most of the backlash out of the axis but there is still a little and it tends to gradually grow again and therefore needs a tweak periodically to keep on top of it. 

Despite this and the slightly rough finish to the mount in places, it does a good job and handles my 100 and 120mm refractors well.

17 hours ago, Louis D said:

Makes you wonder why there is no telescope tripod mount standardization.

Standardization or Standardisation ? 😁

59 minutes ago, mikeDnight said:

.... I regret selling my TMB 40mm Paragon eyepiece.....

I used to have a clone of the Aero ED 40mm (branded Sky Rover) which I believe has the same optics in that the TMB Paragon used. It was a very good eyepiece and well corrected even in my F/5.3 dob (though the exit pupil was a little large in that one !) That is another one that I regret letting go 🙄

I can recall visiting an experienced astronomer in my early years of observing and he had a massive collection of eyepieces including a full set of the TMB Supermono's plus the barlow in a lovely velvet lined walnut box. I guess that I regret not buying a set of Zeiss ZAO's when you could get them (in a nice wooden box again) for around £2K the set although realistically I didn't have that sort of hobby budget back then (late 1990's). 

That looks like an EQ6 hub with CG5 or AVX 2 inch steel tripod legs. Not the normal combination !

I can see why the hub might have been thought to be an AVX because the AVX tripod legs look just like that.

You can get a neat Geoptik adapter to make EQ6 tripods HEQ5 compatible but there is some cost involved:

Geoptik HEQ5 Tripod Adaptor For EQ6 2" Tripods - Rother Valley Optics Ltd

Talking of eyepiece regrets, one that sticks in my mind was the 55mm plossl that I bought from I R Poyser. I've nothing but admiration for what I R Poyser do regarding traditional refractors etc but I really should have realised that a plossl eyepiece in the 1.25 inch format using 55mm focal length ex-military optical components was never going to be a good idea for me 🙄

The finished eyepiece had no eye guard and the field stop was provided by the bottom end of the 1.25 inch barrel. The eye relief was probably about 40mm so I had to "float" my eye that far off the top lens of the eyepiece. I don't think any of the lens elements were coated either. I thought that a 55mm would give me a "massive" true field of view with any scope that I felt like using it in but soon found out that holding the exit pupil that far off the top of the eyepiece was very difficult and the true field was (of course I now know) no larger than a 32mm or 40mm plossl in that format could give. 

All in all a disappointing and frustrating experience in my early days of telescope use and observing. I think I did learn a thing or two from it though 😉

Some of the components of that eyepiece are still rolling around in the bottom of my "bits" box I think, just in case I could think of something better to do with them 🙄 

I R Poyser have also come along way since then and produce some mouth watering scopes:

  Brass Telescopes | IR Poyser – Telescope Makers

47 minutes ago, JeremyS said:

Good to hear you enjoying smaller aperture refractors again, John. Be interesting to hear how you get on.

Thanks Jeremy. Despite the less than ideal transparency I've spotted a few of the brighter galaxies around Leo, Virgo and Ursa Major plus the Hercules and Coma globular clusters with the scope and now Bootes has risen above the conifers, I've managed a lovely split of Izar with the colour difference between the stars showing quite nicely despite the limited aperture. I've just had a look at Alkalurops (Mu Bootis) and managed to split the fainter, tighter pair of that triplet which are 7th magnitude with a 2.2 arc seconds split. I'm just going to wait a while longer before finding Epslion Lyrae, to allow it to rise above the Bristol "glow" before having a go at that famous quadruplet of stars. 

I was not expecting clear skies tonight but here they are, although the transparency seems rather murky.

I'm just playing around with my little 70mm F/6 travel refractor to see how it does on doubles and it is going rather well.

Gamma Leonis (Algieba) and Gamma Virginis (Porrima) proved quite straightforward at around 100x. I was pleased to split the more changing trio of Iota Cassiopeia and then Iota Leonis, which has a separation of 2.4 arc seconds combined with a 2 magnitude difference in the component stars and can be rather tricky in small apertures. For these last two I've upped the magnification to 140x. 

The scope took around 15 minutes to cool from a warmish house but Algieba was split as soon as the scope was put out - the star images just got a little tighter as the scope reached ambient temperature.

I'm looking forward to taking this little fellow away to dark skies later this year - I feel that it's a pretty good performer 🙂