Louis D

My 152 Achro is fine for sweeping star fields, but so is a 6" f/5 Newtonian which is much lighter, cheaper, and color free. The 152 does very poorly on planets and double stars at moderate to high power thanks to excessive CA. DSOs appear about the same as in the Newt. @Stu1smartcookie What exactly do you find the 152 Achro to do particularly well or better than other comparable scopes? The only thing I've found it good for is extreme testing of violet-cut and red-cut filters to find out which (combination) yields the best image of various objects. Because I love tinkering with optical combinations, I find it fun. I'm trying to justify why I'm holding onto it.

I tried them both in the 72ED, 90 APO (both with TSFLAT2 field flatteners), 8" Dob with GSO CC, and 127 Mak. I don't think I had the 6" f/5 Newt or 152 Achro at the time. Both performed pretty consistently across all of them except for the slow Mak which closed the gap between them. I will say the background seems darker in the NT4 than the Redline. It might be for the same reason as with the Vixen LV line appearing darker: the use of rare earth glass types that contributes to their higher prices relative to their competitors.

I won't lie, the 22mm NT4 is nice and sharp edge to edge compared to the 22mm Redline 70. It was enough different to persuade me to retire the Redline to the B-Team case in favor of the NT4 despite the tighter eye relief and slight SAEP in the NT4.

If you look down the tube from the open end, you should see a magnified image of your face like in a shaving mirror when you have your head at the right distance above the end. It's generally around 6 to 10 inches above the end, IIRC. This is just a quick test to see if the mirror can produce any sort of image.

Will probably need a photo down the tube to see if the spider and optics are still there.

APM claims it weighs 331g. I'll have to get it and my gram scale out again to double-check.

Just checked their pricing at CCTS. $119, and they don't charge sales tax to Texas! That's only 20% higher than the 2010 price I paid. I bought my Arcturus binoviewer from them, so I've had a positive experience with them in the past.

I don't recall FC being much of an issue, but the notes in my review/report does state I noted a tiny bit. It must be pretty minor compared to my Pentax XL 14mm which I had to retire after my eyes went fixed focus in my mid-40s. I'll have to look for FC in the Svbony the next time I have it out.

I weighed my APM UFF 24mm to be 346g. Weird that it's heavier than the Altair version.

My 25mm A-T Paradigm (Starguider) has 17mm of usable eye relief with the eyecup all the way down, so identical to the 24mm UFF with eye cup folded down. I've not measured the eye cup up eye relief of either.

Sounds about right. The eyeglasses view in the 22mm Nagler is still wider than the Redline 22mm 70 degree by a few degrees.

I've measured my two 32mm Plossls (a GSO Super and an Orion Sirius) as both having 15mm of usable eye relief. They are right at the limit of usable with eyeglasses for me. I've measured the APM UFF 24mm as having 17mm of usable eye relief which is comfortable to use with eyeglasses resting on the folded down eye cup. I skipped the Meade 5000 SWA 24mm when it went on clearance sale a decade ago because of its tight usable eye relief. The optically identical ES-68 24mm is even tighter due to slight eye lens recession. Ernest in Russia has measured it as having 11mm of usable eye relief.

IIRC, rings on one side of focus and smoother on the other side indicates spherical aberration of the objective. Refer to telescopeѲptics.net Refracting Lens Objective page for more information. I've grabbed a snippet of the spherical aberration explanation below:

It just depends on the use case if you can live with its tight eye relief. Try keeping it around for planetary observing where quickly changing focal lengths depending on second to second seeing conditions is a huge plus. It's fine then because you don't need to take in the entire field of view at once as you might for lunar or starfield observing. With eyeglasses, you lose some outer field. Even without eyeglasses it's difficult to take in the outer field at the shorter focal lengths without tilting your head. Sure, you could Barlow an APM Super Zoom, but that combo is huge in comparison. It would be similar to me choosing to use my Speers-Waler 5-8mm zoom:

Yes, very similar. Distortion characteristics account for the difference in apparent field of view. The ES-68 will tend to stretch things toward the edge more than the UFF. Thus, the moon will remain more round shaped and less egg shaped in the UFF. In my comparison image below, note how little distortion the APM UFF 24mm has center to edge. The rulers maintain roughly the same height edge to edge, and the individual millimeter markings maintain similar spacing center to edge. You may need to select and enlarge the image to see this level of detail. Now notice how much the Tele Vue Panoptic 27mm distorts the rulers' height center to edge. This is how the the TV Panoptic 24mm would appear. Since the ES-68 24mm is a design copy of the Panoptics, I would expect it to have similar center to edge distortion. The Panoptic 24mm would be just as sharp center to edge as the 27mm version if you demand perfection. The ES-68 line tends to lag a bit behind the Panoptics they copied in edge correction. It could be the designer chose to use less expensive glass types that don't preserve edge correction as well.

As everyone on here knows, I'm a stickler for long eye relief. However, I typically only observe planets with my Svbony 3-8mm zoom, so I just roll my gaze from side to side as the planet transits the field of view. That, and the exit pupils associated with 3mm to 8mm are sometimes small enough (scope dependent) that I can get away with observing without my eyeglasses. If you're looking for that "WOW" factor in a long eye relief eyepiece while observing DSOs, I highly recommend the 12mm and 17mm ES-92s. They are so wide that I can only take in the left to right view with my eyeglasses. The top to bottom view is taller than my eyeglasses. The top of the field stop is actually above my eyebrow line. It's a very immersive view that is sure to please. They have 17mm of usable eye relief, which means lightly resting your glasses on the folded down eyecup if you have deep set eyes. They are exceptionally well corrected to the edge as well.

Okay, I found my order confirmation for my 22mm Astro-Tech AF70 in 2010: Order Summary 12/19/2010 9:20:13 PM Quantity Product Status Unit Price Line Total 1 Astronomy Technologies - Astro-Tech 22mm 70° field AF Series 2" SKU: ATAF7022 New Order $99.95 $99.95 Sub-Total: $99.95 Shipping: $7.95 Tax: $0.00 Total: $107.90 That was in the pre-"South Dakota v. Wayfair, Inc." 2018 SCOTUS ruling more or less mandating interstate sales tax collection. Apparently, it was a Christmas present to myself. 😊 So, if you can find it for $130+tax, it's still in line with that price ($100) once adjusted for 14 years of inflation ($143).

Take a look at what images get selected for APOD to get some idea of what makes an interesting image. It's not always just technical virtuosity. Sometimes it involves planning to combine elements into an interesting composition. Being a professional photographer of any subject is a tough profession to make a living out of.

My Meade Safari Pro 8x42 binos from the mid to late 90s look similar, but have a rubber covering and came in black nylon case. Also Japanese and BAK4.

FLO is definitely offering a wider range of focal lengths in this line than let's say CN's sponsor Astronomics in their Astro-Tech PF line.

I've avoided the 21mm Pentax XL early on and 20mm Pentax XW later on due to field curvature. I also retired my 14mm Pentax XL in favor of the 14mm Morpheus as my eyes aged and field curvature become problematic.

Try highly defocusing a bright star or planet next time to examine the image for wobbling and bubbling due to atmospheric distortion.

I've done a similar pairing with my 72ED on one side of my DSV-2B mount and the 127 Mak on the other:

I've found it immensely helpful in getting targets centered. The field of view does vignette somewhat as seen below, but the extra true field opened up is quite useful. As you can see, it opens up roughly 80% more linear true field of view. Light falloff is around 35% center to edge which is surprisingly hard to detect visually. The longer path through the 2" diagonal does necessitate moving the mirror quite a bit to reach focus, increasing the focal length by at least 200mm. Thus, if you're never going to use 2" eyepieces, you'd be unnecessarily decreasing your true field of view with each and every eyepiece by making them work at a higher power.

I would add the 22mm Omegon Redline to Don's list. The discontinued Celestron Axiom LX 31mm, Meade 5000 UWA 30mm, and original mushroom top ES-82 30mm are all more eyeglasses friendly than the optically identical modern ES-82 30mm. However, you have to hunt the classifieds and various online marketplaces to find used or new old-stock versions of them.