Louis D

Here's the 5mm Paradigm/BST up against some other high power eyepieces. It seems to be pretty close to the quoted focal length based on its neighbors' magnifications. I've yet to find a single eyepiece egregiously far off as far as focal length goes. Usually, eye relief and AFOV are commonly exaggerated. Alternatively, the 6.5mm HD-60 should play up the fact it has a 65 degree AFOV like a Pentax XL as seen in the last image.

Claimed, but below is what I measured using eyepiece projection out the eye lens. AstroTech Paradigm is the same as the BST Starguider. The 5mm and 8mm underachieve while the 18mm overachieves. The 5mm and 8mm definitely have a different look to their insides as compared to the 12mm to 18mm. The 25mm has a larger eye lens and longer eye relief indicating a different design as compared to the 18mm and below. The 4.5mm, 6.5mm, 9mm, and 12mm HD-60s overachieve while the 18mm and 25mm underachieve. Notice the 18mm and 25mm have larger eye lenses indicating a different design as compared to the 12mm and below. By comparison, the Pentax XLs, XWs, Delos, and Morpheus are all spot-on their claimed fields of view (or consistently overachieve by ~2 degrees).

I always like how my 5.2mm Pentax XL resolves globulars into sparkly diamond dust.

I would recommend the 30mm APM UFF for edge to edge sharpness and little to no inherent field curvature. I replaced my 27mm Panoptic with it and have been very happy with that decision. At very high powers, folks swear by the Vixen HRs and Tak TOEs. In the middle, the TV Delos, Pentax XWs, and Baader Morpheuses are very good choices. The TV Delites are another good choice with slightly better correction at a slightly narrower field of view. There are lots of excellent options out there beyond these as well.

The Vixen LV/NLV/SLV are 45 to 50 degrees AFOV, 16mm to 18mm of usable eye relief, high quality lens polish, and very good multicoatings. They offer up excellent edge to edge sharpness over a limited field of view for the eyeglass wearer on a budget. The Starguider BSTs offer 57 to 62 degrees AFOV, 12mm to 18mm of usable eye relief, mid-quality lens polish, and good multicoatings. They offer up a near-superwide field of view, good central sharpness and decent correction to the edge on an even tighter budget. They may not be the best for eyeglass wearers, though.

That's the one focal length in that line of eyepieces I don't have. I have read it does very well when conditions allow.

I didn't even realize aerosol deodorant still existed after it fell out of favor in the 70s and 80s. It's pretty rare here in the states at maybe 2% to 5% of total shelf space and sales. Don't feel like you have to be a slave to a single case. I started out that way, but soon realized that as I upgraded, I liked to keep the old eyepieces around for comparison sake and relegated them to a second-string or B-team case. Eventually, this expanded to a C-team case, an overflow case, a binoviewer case, a travel case, and a couple of cases dedicated to complete mid-range sets. Good choice, the vast majority of my eyepieces are kept vertically to save space. I think glowing red cases are so cool looking. However, I have enough ambient light in my backyard, that I never have trouble picking out eyepieces there. Perhaps if I ever get my vacation/retirement home in the mountains of southwestern New Mexico, I might have to revisit the whole lighted case issue.

There have been a lot of new satellites recently put up by competing concerns trying to bring internet access to the entire world. Also, there's a lot fewer planes flying right now, so that probability has significantly dropped.

The American West, like the Australian Outback, both have lots of room to spread out in. Mike Clements is in Utah, which has vast stretches of emptiness like most of the rest of the Mountain West and the Desert Southwest.

I was wondering why the following books are never recommended on SGL for beginners: The Deep-sky Imaging Primer [by Bracken] Getting Started: Long Exposure Astrophotography [by Hall] Beginner's Guide to DSLR Astrophotography [by Lodriguss] The Astrophotography Manual: A Practical and Scientific Approach to Deep Space Imaging [by Woodhouse] Is it because Making Every Photon Count is just that much better or the ones I listed are just much too advanced for beginners?

Amazing what a tiny bit of misalignment in optics can make in an image.

So, that's 2000 grand = 2 million? Pretty deep pockets there. Except for Uranus and Neptune, planets are super easy to find due to their brightness. DSOs can be much harder to find, but the thrill can be in the hunt. For 2000, I would look to get a nice, custom made, used truss Dob with a hand figured mirror. I can't tell where you're located, but in the US, these come up all the time on the astro classifieds. The optics and mechanicals are much better than commercial Dobs and really hold their value well.

If the ZWO camera doesn't have it's own lens, I don't know that the Delos will project a flat enough field onto its imaging chip to get a well focused image across it. I assume you're trying eyepiece projection rather than afocal projection, which is what you get holding a cellphone camera up to an eyepiece. The camera's lens in that case takes care of flattening the field for you. You'll need to find some sort of adapter to attach them since there's no thread on the top of the Delos unlike the M43 threads on top of Pentax XWs and Morpheuses.

Probably because it's easier and faster to mill than steel, and you end up with a lighter product.

As @ronl suggests, the diagonal might be damaged. It's easy enough to verify by putting an eyepiece directly in the focuser draw tube and looking straight through. You'll need about an extra 60mm of out-focus (extension) to reach focus without it in the optical path, so you may end up having the hand hold the eyepiece behind the fully extended draw tube to reach focus.

This is probably true. For example, anyone who remembers Van Slyke Instruments can attest to his very functional looking, but exquisitely engineered products.

Sorry it didn't work out. From my frame of reference having used the Speers-Waler 5-8mm zoom for years, the Celestron Regal seems almost perfectly parfocal in comparison. If a BHZ ever comes up for under $200, I might look at getting one for comparison sake.

???? 🤔 I'm not sure as an American if I should take offense at this or be flattered. It's not like it's the size of a house and flying an American flag held up by Barbie.

I sometimes put my TV PBI in my 2" GSO ED 2X Barlow for the night in my Dob to double my focal length for all my eyepieces. Do not try to use a 2", non-telecentric Barlow with near maximum field 2" eyepieces. They will have edge cutoff, not vignetting. It's like there's a new field stop inboard of the physical field stop. The discontinued TV PBI (Panoptic Barlow Interface) works well with either the TV Big Barlow or the 2" GSO ED Barlow (nearly the same focal lengths) to convert them into telecentric magnifiers like the TV Powermates.

With no budget, how about a Celestron NexStar Evolution 8 EdgeHD with StarSense? A beginner here in Texas brought his to a star party a couple years back and he seemed really pleased with it. The views were quite nice as well. It was super easy to setup, align, and control from a tablet.

Not quite 200mm aperture, but the Takahashi Epsilon 180 ED f/2.8 Newtonian Astrograph Reflector should be able to capture M31 with its 500mm focal length.

With a 2000mm focal length, you'd be pushing the magnification to very high levels with a ~9mm eyepieces (2000/9=222x). Sky conditions may not often allow for that level of magnification. I would recommend staying between 75x and 150x for now. You've got the lower end covered with the 25mm Plossl for now, so I'd look into getting a 12mm to 14mm eyepiece for the upper end. The 12mm Astro-Tech Paradigm is pretty decent for $60, especially in an f/10 scope.

With a GSO/Revelation coma corrector, I am able to reach focus on my Dob with a DSLR despite most eyepieces coming to focus with about 20mm of in-travel to spare. That's how I took the attached photo.

Would the Sky-Watcher Quattro f4 Imaging Newtonian work better due to it's shorter focal and tube length, dual speed focuser, and photography dedication, than the 200p at f/5?

That's wild. I live over 25 degrees south of that, so we have plenty of astronomical darkness even in the summer. It would be about the same as being in Cairo, Egypt on your side of the pond.