Louis D

Definitely give that 3mm optical path length Baader adapter @Waldemar suggested above with the T2 threaded visual back attached to it. It would replace the existing visual back and probably shorten the optical path length by 20mm to 25mm.

15x70s are great for scanning the skies. You will need to be seated and possibly reclined to use them effectively hand held. 8x42s are a great companion to them for wider views at about half the power. Stick with porro prism designs to keep down the costs while maintaining good correction. They will weigh a bit more than roof prism designs.

As Don suggests above, I use a TSFLAT2 attached in front of my GSO dielectric diagonal in place of the normal insertion tube. For my 400m to 600mm focal length fracs, I find about 15mm of extension works well. For your scope at about 800mm FL, you may want to dispense with any extension. I use either the Blue Fireball M48 (2" Filter) Male Thread to SCT Male & M48 (2" Filter) Female Thread Adapter # C-05 with a 15mm extension or the Blue Fireball SCT Male Thread to 2" Nosepiece Adapter - Short # C-02 without any additional extension. Either combination works really well to flatten the fracs' fields for my presbyopic eyes.

Sorry, didn't mean to offend. Pretty much everyone drives around here because mass transit sucks something fierce. My daughter was a big proponent of mass transit during her college years until she got an internship downtown. She tried the whole mass transit thing for a month and realized it was awful. What should have taken 35 minutes to get there took over an hour if she caught the express bus. However, it only ran every 30 minutes for 2 hours in the morning and evening. If she missed one, she'd either have to sit and wait close to 30 minutes for the next one or take a local bus that takes 1.5 hours to get to downtown due to all the stops in between. She ended up borrowing a family car for the summer or catching rides with friends and coworkers. You can't live near work because decent houses in the city start at over $1 million. Even dumps are over $500,000 now. Apartments are over $1300/month, so you might as well put that money toward a house in the 'burbs.

You could try using an electric hot knife. I'm sure there's a UK retailer of these things.

But it's getting more active now that we've passed solar minimum.

The Dob is much easier to set up and observe with while seated. My refractors are nice for the purity of the star images, but can be a pain to use while seated as you said. I can't stand and observe for more than a couple of minutes before fatigue sets in. I use both just to change things up.

I would probably recommend a carbon fiber tripod to keep the weight down if traveling by plane. That, and get a compact alt-az mount as some have suggested above. A 72mm ED refractor would work well on camping trips, but it will be severely limited by its aperture for resolving smaller DSOs. They are great for scanning the skies at low powers and for looking at midsize and large objects, though.

I put together a 127 Mak and 60mm finder scope combination on a DSV-1 mount with a Manfrotto 3068 tripod, all of it second hand, for my daughter's car camping trips. It works well to provide wider field views through the finder along with higher power views through the Mak without taking up much space in the back of her mid-sized SUV. The OTA and finder go in a gym bag, the tripod and mount in a long tripod bag, and the eyepieces in a pistol case. I was able to cobble the whole thing together a couple of years ago for under $500.

Telrad outer circle is 4 degrees.

I just double checked my cheap 45 and 90 degree Amici prism diagonals, and the OP is correct. They are vastly stopped down. I only use the 45 degree ones for terrestrial observing and the 90 degree one in a 60mm RACI finder, so the vignetting has never bothered me. I've never experienced blackout with either, even with widest field eyepieces; but that was always with refractors. Perhaps there is some interaction with the Mak's central obstruction going on as well here?

Another widest field option in a 1.25" barrel is the 24mm APM UFF. It does quite well up to the last few degrees of field where it gets a bit indistinct. The rest of the field is quite sharp. I measured mine to have a 27.5mm effective field stop diameter, which probably accounts for the slight fuzziness at the edge since that is pushing what is possible in a 1.25" barrel. By comparison, my 26mm Plossls have 22.3mm and 22.6mm field stop diameters. I measured my 25mm AT Paradigm (BST Starguider) to have a 26.7mm field stop diameter, so it comes close to maxing out the available field of view in a 1.25" barrel. The 24mm ES-68 at 27.2mm FS diameter has greater distortion to get to 68 degrees apparent field (AFOV), but not that much more true field (TFOV). A 0.5mm difference in FS diameter isn't all that much. If you already have 2" eyepieces and are comfortable with them, I would steer you toward the 22mm Omegon Redline (TS-Optics Expanse, Technosky Superwide HD, etc.). They are better corrected than any of the above to the edge (just slightly behind the 22mm NT4), have excellent eye relief (once the eye cup is unscrewed) for eyeglass wearers, have a 28.4mm FS diameter (thus the 2" barrel), have a true 70 degree AFOV with very low distortion, and are lower priced than the APM or ES alternatives.

The only thing known to correct achromats for color is the long discontinued Aries Chromacor.

I tend to use 1200mm and shorter focal length scopes. I do have a 15" f/5 Dob that might make those closely spaced eyepieces useful, but I haven't used it in years since my back got messed up in an auto accident.

I've got a similar lineup in my A-team case except that I don't have the Delos 6mm and 8mm eyepieces, or really anything in either focal length range aside from my 5-8mm SW zoom which has too little eye relief for me. I've thought I might want something in those slots, but I find myself happily skipping from my 9mm Morpheus to my 7mm XW to my 5.2mm XL to my 3.5mm XW without feeling like I've jumped too much in any one step, except perhaps with the 3.5mm XW. My question is, do you make much use of those those single digit Delos eyepieces? Or do you prefer them and skip the XWs? I'm thinking a 4.5mm Morpheus or Delos might get more use than either a 6mm or 8mm Delos.

Yes, Skywatcher prices, along with most astronomy gear prices, have gone up quite a bit. Those of us in the US are now getting hit with a special 25% tariff on Chinese made items on top of those price increases, so consider yourself fortunate you're not having to deal with it as well.

If you can rig up a way to attach the camera in place of the scope, of course you can use the mount sans telescope. It would definitely resist wind much better with a camera only due to not having a large sail of a scope tube attached to it. Would the mount track more accurately? Barely. It will still have uncorrected periodic error (stars track small orbits) among other issues. Again, keep the exposures short for later selection and stacking, and it would probably work well enough to learn basic astrophotography on.

SN 00007 makes it one of the first 10 produced. That's a bit of a collectors item. Enjoy! Clear skies to you.

Mathematically, yes. Reducing image scale reduces the visibility of tracking imperfections. I would avoid the cheap 0.5x focal reducers unless you're using a really small sensor. They introduce all sorts of outer field aberrations like field curvature and spherical aberration.

Yes, I bought a dielectric 1.25" diagonal with a rigid case to safely hold the BV weight while minimizing the optical path length. I normally use a 2" diagonal for mono viewing because I have so many 2" eyepieces.

It's not that it won't track properly, it just won't do it accurately enough for long exposures. You'll start to see stars wandering around a bit due to inaccurate tracking. The mount also won't be able to resist gusts of wind, so you'll need to shelter it from wind somehow. It would be fine for short exposures for later stacking.

Goto mounts will have field rotation which limits how long individual frames can be. Off the shelf cameras won't be as sensitive to the far red where H-alpha resides as a dedicated astro camera would be. It is an important nebula emission line for DSO imaging. Here's a mega-thread on DSO imaging without an EQ mount:

Agree with @Highburymark about merging high power eyepieces in a BV. The problem is that they expose even the slightest miscollimation of the BV. I just use a pair of Celestron Regal 8-24mm zoom eyepieces with a 2x Barlow nose piece that yields 3x in the BV. That way, I'm operating the zooms at 2.7mm to 8mm. Absolutely no problems merging the images at any focal length, although I rarely go much higher than about 12mm natively (4mm Barlowed) on the zooms in this mode due to viewing conditions and exit pupil issues. I also have no problems matching zoom focal lengths. I zoom both roughly to where I want to be power-wise, tweak focus using my dominant eye if needed, and then fine tune the focal length of the zoom for my non-dominant eye until the images exactly merge. It's actually easier to figure out best merge than best focus in my experience.

Small DSOs like globular clusters look really poor in ~75mm scopes. There's simply not enough resolution to resolve them at 200x and above in my experience.

Then I would invest in a binoviewer. Even the entry level units are quite good. I saw far more detail on Mars during this latest opposition with my Arcturus binoviewer and two 50 year old B&L microscope eyepieces than with any of my XL, XW, Delos, or Morpheus eyepieces in mono mode. There's no substitute for using two eyes to pick out low contrast, fine detail.