John

Ah, the old "wooden stick" ploy

Personally I feel that the diminishing returns on larger apertures are in terms of portability / ease of set up rather than performance, especially where deep sky objects are the target. Aperture really is "the king" there but scope weights and size seems to take a big jump once 10 inches of aperture are exceeded.

@merlin100: thanks for the translation. @Marc jacobs: welcome to the forum but please could you make all posts in English as per the rules of the forum ? Thanks.

2 inch eyepieces give you a wider field of view, nothing more in optical quality terms. I use them in small scopes when I want a large field of view. For medium and high magnifications I use 1.25 inch eyepieces even with my 12 inch aperture scope. The 31mm Nagler is a 2 inch giant - here in my 102mm refractor where it shows 3.8 degrees of sky:

A 150mm F/5 newtonian can show the planets well. Magnifications of 130x - 230x will prove the most effective for this purpose. Many (hundreds) deep sky objects are within the grasp of such a scope as well. Generally lower to medium magnifications are used to observe deep sky objects, eg: 25x - 80x Decent quality eyepieces can be bought for between £30 and £50 new, less on the used market. A good example of such an eyepiece are the BST Starguider range as sold here by First Light Optics: https://www.firstlightoptics.com/bst-starguider-eyepieces.html It is useful to have at least 3 eyepieces to give low, medium and high power magnifications. Many folks end up with quite a few more though ! You might find that an illuminated reticule / red dot type finder is a good addition to the scope. These are zero magnification but appear to project a target against the sky showing just where the scope is pointed. This is a good one and it can sit alongside the optical finder you currently have: https://www.firstlightoptics.com/finders/rigel-quikfinder-compact-reflex-sight.html Whatever finder you are using, it is vital that it is adjusted so that whatever the finder is centered on is also exactly what the main scope is centered on. This can be done in daylight using a distant target (ie: tree, chimney etc) and a low power eyepiece in the scope. A good star chart is also essential to help you work out where your target objects are in the sky. There is also the free software Stellarium which shows you what is where and when: https://stellarium.org/

Some of my best ever views of Saturn came with an older C8 that I used to have. On one memorable Summer evening Saturn was high in the sky (unlike now ) and the views of Saturn using a Tele Vue plossl 8mm (250x) were truly breathtaking and steady as a rock. It is worth having something that can take you a bit higher than that though, for periods of really good seeing on a suitable target. Something around 7mm (285x) or even 6.5mm (308x) would be good. The Baader Morpheus 6.5mm would be a very nice tool for such use I reckon. The Pentax XW 7mm is also rather nice

My Pentax XW story is a little different. FLO loaned me the 10mm XW and then the 30mm XW a few years back to compare them with the Naglers that I was using back then. Rather to my surprise I found that I slightly preferred the 10mm XW performance to the 9mm Nagler T6 that I had despite the reduction in AFoV. What I wanted though, being still a "wide field junkie", was the neutral tone, sharpness and lack of light scatter of the XW's combined with a very large field of view. Unfortunately for my bank balance the Ethos range came along ......

It depends on the tube length as well. This 150mm F/12 refractor weighed 14.5 kg but the long tube meant that the EQ6 was not all that stable even for visual observing. And that was with 3 inch steel tubed tripod legs !

Its useful to show scale - I don't actually use the Nagler 31 that much

Powermates are superb - as @JTEC says, practically invisible in the optical path apart from the magnification increase. They can create quite a stack when used with a long eyepiece though !

I agree with Peter (above) - most likely an F/5 with a 750mm focal length. I think that scope is one of the older Orion Optics ones that uses a single vane secondary support like this ?: Orion used to have a series called the Europa which yours could well be one of. It is worth blowing the dust off the mirrors using a manual blower but don't touch the mirror surfaces. The collimation may need attention if it's not been adjusted for some time. M31, the Andromeda Galaxy should certainly be visible through the scope but you will need a low power eyepiece and even that wont show the whole thing - it's a big object !

I go for the wider field every time when using my 12 inch dob, personally. I don't find that I need to roll my head to see the 100 degree field but thats not the same for all I realise. I've had galaxy spotting sessions where the 21mm Ethos is the only eyepiece I've needed. I had the ES 20mm 100 before it but could not resist acquiring the Ethos 21 despite the ES being pretty good itself. I have some light pollution to contend with which is why the 21 Ethos gets more use than the 31 Nagler. Darker background sky.

I'm going to stick with my Nagler 31mm and Aero ED 40mm in these focal lengths I think. I don't use 40mm eyepieces that much but the Aero ED seems good when it's been used, even in my F/5.3 dob. The best one in the Aero ED series I think. I don't actually use the 31mm Nagler that much but I know I'd miss it if I parted with it. Most of my low power observing is done with the 21mm Ethos.

The scope looks very similar to my 1960's Tasco 60mm F/13.3 refractor. Possibly from the same manufacturer. My Tasco has a good objective lens but the stock eyepieces and rather wobbly mount don't really do it justice. I've tried it on a good mount and with better quality eyepieces and the objective performs as a good 60mm achromat should.

The step from 114mm to 150mm newtonian might show some small gains, assuming a similar optical quality, especially on deep sky objects. Modest though, all things considered. Moving from 114mm to 130mm does not seem worthwhile to me. I think you would need to think about moving to 200mm to see noticeable all round improvements. If we were talking about refractors the step from 114mm to 150mm makes more of an impact.

I've tried bino viewers a number of times but I don't get on that well with them either while other experienced observers are very happy with them. Eyepieces do seem to be very personal choices don't they ?

I agree with Olly. I have the Ethos in 21mm, 13mm, 8mm and 6mm focal lengths and they are superb eyepieces and not just in terms of their field of view. The 21mm is eye-wateringly expensive if bought new though. The APM 20mm HDC-XWA is an excellent alternative at substantially less cost.

The image is only as good as the weakest link in the optical chain. In this case I think it's clearly the cheap barlow lens. There are pretty good ones available at reasonable cost as mentioned in the posts above.

I go down both routes with my refractors. I have a 21.5mm - 7.2mm zoom eyepiece which I use with a Baader 2.25x barlow to give a 9..55mm - 3.2mm high power zoom which I have found both good optically and very useful for finding the right magnification for particular target / seeing conditions. Coupled with a 30mm wide angle eyepiece the zoom + barlow makes a very good 3 piece set for travel or outreach. I also have a number of fixed focal length eyepiece down to 3.5mm and the excellent but sadly out of production Nagler 2mm - 4mm zoom. I've been pleasantly surprised how often I can use 250x - 300x or more magnification with my refractors but having the capacity to fine tune the power to suit the conditions / target is important so small steps in focal lengths makes sense when high power observing.

Here is a web page describing some other modifications to the Skywatcher 130m which has some photos and diagrams of the primary mirror cell including the attachment to the tube. These suggest non-captive nuts on the screws that hold the cell to the tube: http://astrobeano.blogspot.com/2013/04/moving-mirror-on-skywatcher-130m.html Also here is a thread from a while ago on someone wanting to remove the primary mirror for the same reason that you do. Skywatcher have not made it an easy task !:

Good advice from Louis. For a £100 per eyepiece max budget the Vixen SLV's are very good. Spending 3x more will get a wider field of view but not better optical performance. If you get an eyepiece set of excellent quality now, it will last you for years and years and serve well in future scopes you might own

Its worth remembering that filters such as the UHC and O-III only really have an impact on nebulae. For clusters and galaxies, dark skies are the best "enhancer"

Still clear here but somehow the seeing is not quite what it was and the transparency no better. While it's good to actually be observing, I feel that I'm "going through the motions" a bit just now. I can pick out stuff like M51, M97, M81+82, NGC 2903 etc, etc but I know that I've seen them looking better. Perhaps its time to pack up and come back into the warm

It's hardly blazing tonight but no dimmer either. The fight back begins !

The Antares 105mm refractors looked great but were internally stopped down to around 95mm effective aperture. Challenging to mount such long tubes steadily as well. Perhaps choose elsewhere for your 15th / 16th scope ?