John

The objective cell on the ED100 should unscrew from the tube allowing you access to the inner face of the objective lens for cleaning. Hopefully the fungus has not occurred between the lens elements (it is an air spaced doublet) because that will require the objective to be removed from the cell and split to access those lens faces. I've done a few of those and they can be a fiddly operation. I would not do a triplet objective - that is a much more specialist operation.

On some targets you will notice quite a difference - globular clusters are an example. On others, not so much and what you actually see depends on a whole lot of factors other than the scope aperture as @vlaiv says above. Personally I find the 4 extra inches well worth having but the scope size and weight has increased markedly to get this and this needs to be considered as well:

OVL are the importer but it is usually more effective to contact vendors such as First Light Optics (FLO). Here is there website: https://www.firstlightoptics.com/

Amazing what is possible with simple tech ! I tried to get the ISS crossing the moon with my DSLR mounted on an undriven scope and got it in a couple of frames which I have made into an animated GIF. The whole crossing took just a second or two and the moons was partially behind tree branches so I was pleased to even get it in 2 frames:

The diagonal on the Bresser's is their weakest point IMHO. All plastic apart from the mirror. I would budget for a replacement from the off. Meade used to supply the same diagonal with their AR5 and AR6 refractors

Well, I used it with the 8mm Ethos in 2 inch mode and it provided the same image scale as the 5mm eyepieces that I was comparing it with at the time.

I think it works at 1.6x in 2 inch mode anyway. The one that I used to have did.

I find 21mm - 13mm - 8mm - 6mm deliver 80% of my observing with my 12 inc F/5.3 dobsonian. They are my core set with this scope. I have shorter and longer focal length eyepieces but they don't get as much use as the above.

Either of the could be good - there are happy and satisfied owners of both types on this forum. They both have strengths and weaknesses though so I guess its a case of deciding what you are hoping for from this new scope and the extent to which the two you have initially selected might match those aspirations or if there is a better option out there within your budget.

You are more likely to see optical issues with the F/5 but they are not designed for high power observing so it might not matter too much. The F/8.3's are generally optically sound but you can still get some spherical aberration - it's very common with the chinese achromat refractors. Both will show some chromatic aberration, the F/5 quite a bit more than the F/8.3. If you are looking for optical perfection in these low cost scopes you may have to reject a lot of samples.

I've been reminding myself of stuff relating to barlowing / Powermating Ethos. Makes my brain ache !!!: https://www.cloudynights.com/topic/132768-ethos-mag-factor-with-tv-barlows-powermates/

That's not the way that I used the 1.6x Barlow when I was comparing it with other 5mm eyepieces as the photo I posted earlier in this thread shows I think I would have noticed if the Ethos 8 plus 1.6x barlow combo was delivering more (or less) than a virtual 5mm eyepiece as I compared the views with true 5mm eyepieces. By all means try it though - nothing to loose !

I was using a 31mm Nagler so 51x and a 1.6 degree true field. Enough to fit the Eastern or Western segments of the nebula in the field but not the whole thing. Using the O-III filter makes a huge difference to the visibility of this object though. I was just trying it without to see if I could see anything of the Veil filterless as the sky was quite good last night.

I agree about changing the diagonal to a 90 degree mirror one. I just feel that the F/5 120mm will offer something a bit different from the VX8L. If the intention is to use the scope for observing the planets, moon etc I think the longer one will be better. The VX8L would out perform it by some margin on these targets though.

What are you looking for from the refractor - deep sky observing or planetary / lunar observing ? To compliment your VX8L I'm tending towards the shorter Startravel 120 as a portable deep sky / wide field scope but that might not be how you see things ?

Great shots Philip ! Is "Night mode" on the S10 a special app or a standard feature ? I wonder if my 2017 A3 has it ?

Nice report, I enjoyed reading it - thanks for posting

Neptune looks quite "star like" at lower magnifications although there is something about the way it looks through the eyepiece even then that makes you think that it is a planet rather than a star. The tiny disk becomes visible at about 80x - 100x but it is tiny - just 2.5 arc seconds so it would fit into the gap between the wider pair of Epsilon Lyrae ! Found this piece on spotting Phobos and Deimos: https://astronomynow.com/2018/07/30/find-martian-moons-phobos-and-deimos-at-the-red-planets-closest-approach/ They should be possible with my scope but I need to choose a time when their elongation from the planet is more favourable and when there isn't a layer of misty cloud around. The latter did help enhance the contrast of Mars a bit though I think, until it got too thick that was

Good point but I'm pretty sure that I did tke them off when trying to reach focus with the Mk II 1.6x barlow. I really wanted to get it to work because it is a much lower cost alternative to the Powermate 2 inch 2x and gives slightly more useful focal lengths. No matter, that was sometime ago. I'm glad the current one works well and I might pick up one at some point. It's not as if I'm lacking in high power options for my 12 inch dob with the XW 5mm and 3.5mm and the Nagler 2-4mm zoom. Using 795x on Mars last night when trying spot Phobos was interesting

One of these perhaps ?: https://www.bresser.de/en/Astronomy/BRESSER-Messier-AR-102xs-460-Hexafoc-Optical-Tube.html

Well I didn't see Phobos or Deimos - a misty cloud layer spread across the sky obscuring all but the brightest stars. I did get some fine views of Mars though with the thin cloud acting as a rather effective natural filter. All in all a very pleasing night

Astro Systems FG150 newtonian I think. I used to have one many years ago. Made in Bedford. They also came on an alt-azimuth mount on a pillar. Helical focuser was an option. Mine had a Vixen rack and pinion. David Hinds mirrors in those - good quality. Peter Drew (a member here) had some involvement in the design I believe along with Rob Miller who went on to work with Astro Physics in the USA.

I found that the 6mm and 8mm Ethos came to focus just fine in the Mk I version of the Antares 1.6x barlow inserted using the 2 inch fitting but the Mk 2 design needed a lot more inwards focuser movement which was too much for my 12 inch dob. If the latest version of the 1.6x barlow keeps inwards travel needs to a reasonable level then I'd like to try one again.

Good to know that the mount will handle the ED120 OK. I'm not surprised that the Porta II won't. I found that the AZ-4 was not really up to it either even when put on a sold 2 inch steel legged tripod. I use the Skytee II or Giro Ercole for my ED120 now. Very solid. Hope you manage to find an 8mm fitting slow mo cable soon.

A rather nice clear and dark night tonight. I had a short time with my 100mm refractor observing Jupiter and Saturn. They were OK but the seeing was not that great. Because of the dark sky I decided to get more aperture out so out came my 12 inch dobsonian. While the rising moon was masked by conifer trees I managed to have a lovely late Summer DSO tour. All the old favorites were showing really well with my 12 inch dob. First time for ages that I've had this scope out. The Veil Nebula was excellent with the 31mm Nagler and Lumicon O-III filter and the Crescent Nebula also showed it's subtle curves. The Dumbbell Nebula was superb with and without a filter. Followed this with further planetary nebulae, the Saturn Nebula, Blue Snowball (nice detail here) and the Little Dumbbell Nebula. Off with the filter and in goes the 13mm Ethos to have a look at some globular clusters. The magnificent M15 and M2 and the fainter NGC 6934 and M72. Lots of resolved stars in the brighter of those. With moonlight starting to invade the sky, I've switched back to planetary observing and picked out Neptune in Aquarius. I wanted to see if I could spot Neptune's brightest moon, Triton which I have managed in the past with this scope. I piled on the magnification with the Pentax XW 3.5mm for 454x and Neptune's tiny 2.5 arc seconds disk was surprisingly well defined even at this high magnification. I carefully examined the background sky within a few planet diameters using a sort of "1000 yard stare / averted vision" technique and a suspect point of light popped in and out of visibility around 10 arc seconds to the south east of Neptune. I observed this though several drifts across the eyepiece field and made a rough sketch of its position. Back inside to check Cartes du Ciel and, lo and behold, Triton is just where my suspect point of light was shyly blinking in and out of view. This distant rocky / icy world shines at magnitude 13.5 so I was pleased to pick it up with some moonlight in the sky. Waiting for the Moon and Mars to rise into visibility now. Who knows, maybe Phobos and Deimos will be possible ?