Louis D

You learned that an alt-az mount is a much better choice for a grab and go setup. That, and having your scope setup at the right height to enable sitting while observing is essential to avoiding backaches.

Most in the US use 1/4-20 threading. You'll want hex socket cap head screws regardless of thread size.

It takes a lot of crud on an objective to become noticeable. This is nowhere close to that level.

Sounds good to me! 😄

The 31mm Nagler T5 might be another option to replace the 32mm Panaview SWA if you like 82 degree eyepieces. The Nikon NAV-HW 12.5mm and 17mm eyepieces are another premium hyperwide option. Each comes with a dedicated screw on optical element to allow the 17mm to become a 14mm eyepiece and the 12.5mm to become a 10mm eyepiece with no optical quality loss. Most reviewers indicate they slightly edge out the Ethos and have more comfortable eye relief. The 17mm can be difficult to achieve perfect coma correction in a Paracorr II, though.

Looks a lot like the ebay ones I was referencing. My point exactly. I've found power supplies are much simpler to replace than obsolete laptop batteries. Most of the generic replacement batteries don't have the necessary electronics built into to them to take a charge.

You might be able to find a step ring threaded all the way through that would be much thinner than the original lock ring. I just have no idea what thread size it's using.

I'm no imager, but I use a TSFLAT2 on my 72ED and 90mm APO refractors to good effect. I can't stand field curvature with ultrawide eyepieces and low powers. I attach it to the front of my diagonal, replacing the 2" diagonal's nosepiece. I use 15mm of spacer extension for best correction visually.

Me too. Nothing wrong with such talk when everyone in the room is an astro geek.

I haven't tried it with an SCT, but in my f/6 and faster Newts, I start noticing secondary shadow on the moon and sun at around 5mm to 6mm exit pupil. It's quite strong by 8mm. When fully dark adapted and looking at DSOs, I can't recall ever seeing secondary shadow at any exit pupil. Getting to a large exit pupil at f/10 in an SCT is much more difficult than at f/5 in a Newt. Perhaps with the SCT + F/R operating at f/6.3 it would be more of an issue.

Here's my post on the subject: As I say in the post, I've photographically measured about a 35% drop off in illumination toward the outer field. Visually, I can't see it at all.

In that context, that should be fine. Just as when I use a 40mm 2" eyepiece to center an object in an f/5 scope producing an 8mm exit pupil. I don't really care about the wasted photons in that use case, I just want the object within the field of view to avoid searching about for it.

Further, assuming the OP has a C5, using a 0.63x focal reducer will show more field with a 32mm or 40mm Plossl, but with outer field vignetting as with a widest TFOV 2" eyepiece used with 2" accessories on the C5. TANSTAAFL

You could mount a 2" visual back and 2" diagonal to a C5 (assuming that's your scope). You'll just get vignetting like I do with my 127mm Mak and 2" visual back. The fully illuminated image circle is limited by the approximately 1 inch diameter rear baffle and rear port. Exit pupils larger than your fully dilated eye pupil will waste aperture collected photons on your iris instead of sending them to your retina. Sometimes, this is acceptable when trying to achieve maximum TFOV at any cost. You're mixing up eyepiece AFOV (apparent field of view, measured in degrees and is completely independent of the scope) with TFOV (true field of view which is also measured in degrees on the sky, but is dependent on the scope it's mounted to). However, TFOV is dictated by the field stop diameter of the eyepiece. Between two eyepieces, the one with the larger field stop will yield the larger TFOV in any scope used in common between the two eyepieces.

Around here, we have to get below the line where drought and flooding affect the top layers of soil. A lot of houses built on slab foundations instead of pier and beam foundations flex and crack as the soil hydrates and dehydrates over the span of months to years. I would expect the same to happen with pier footings not set deeply enough.

You could search on ebay for a cheaper alternative. Just make sure it supplies at least 5 Amps at 12 V. The 12 V connector is pretty standardized by voltage with a positive tip. Celestron lists 3.5 Amps minimum for their AVX mount with positive tip.

You must be a hoot at a party when something astro related comes up in small talk: "No, that's not quite accurate. You see, back when f/8 was considered a fast scope...." 😉😁

UPS and FedEx here in the States both way outperform their USPS counterparts. I've lost track of the number of misdelivered USPS packages or packages marked as delivered when they were still in the system just to keep their on time delivery metrics high. Since USPS packages go into locked mail slots, I can't just go and find them when they're delivered to the wrong slot. I have to hope my neighbor doesn't check his mail and decide to just keep my package for himself (too indifferent to do otherwise). I then need to catch my postal worker at our mailboxes the next day and force them to check the other boxes for my misdelivered package. By comparison, this has happened only once with UPS and never with FedEx. DHL is barely present in the US. And with UPS misdeliveries, I just go around the neighborhood once I'm notified it's delivered but not on my doorstep and check the usual suspects' doorsteps that have the same street address but on a difference street and just grab my package for myself. I do worry someone will think I'm a porch pirate doing that, though.

As far as cheaply priced tele-extenders, Astronomics is now marketing a 2x version under their Astro-Tech brand for $60 (plus sales tax). I think it's getting decent reviews on CN. Perhaps @FLO could bring it to the UK under one of their house brands?

Glad to hear you got that sorted out. I have a 2.5mm TMB PII clone with no rattling. For the price ($35 shipped), it's actually a pretty decent eyepiece. It's just too much magnification most nights.

Sure, send it our way. We're short about 12 inches at this point in the year, and many more over the previous 2+ years. Our main reservoir for drinking water is down to 35% full. We really need a tropical storm or similar to deluge us in rain for days.

I bought a second hand 90mm TS triplet here in the States without any issues during shipping. I'm sure FLO would do at least as well if not much better packing the scope and choosing a courier. However, SCTs and their thin corrector plates are another issue vis-a-vis shipping:

That, and those cheap 0.5x reducers produce a highly curved field with lots of outer field aberrations. The best use for one I've found visually is to increase the field of view of my binoviewers in scopes with limited back/in focus. I have a 1.25" 2x Barlow element up front followed by 45mm of spacer rings followed by the 0.5x reducer. There is some vignetting and outer field aberrations, but I can reach focus in my Dob with only 1.0x magnification instead of my normal 3x magnification of the Barlow element alone. I've essentially created a relay lens. Conceptually, the way it makes the exit pupil larger is by compressing the entire exiting light flux into a smaller image circle at a lower power. This also means that widest true field eyepieces will be vignetted if used with a focal reducer. For photography, you can't use as large of an imaging sensor when using a telecompressor (focal reducer) because of the reduced image circle.

Once you do get it, let us know how it worked out. We're under clouds here in Texas for the foreseeable future as well, but we need the rain, so we're not complaining too loudly.

You probably have already experienced this yourself, but swapping large Barlows/Magnifiers in and out of the optical train is a pain, even on a Dob. I tend to leave one in for an entire viewing session when conditions allow for the higher powers. This works okay for 2x, but I'm not sure how well it would work for 4x.