Louis D

4 hours ago, globular said:

Does the 22mm Nagler make this list too? It’s on my short list, with the ES 92s, for a glasses friendly fairly wide set.
On paper it has 19mm eye relief like the 31. In actual use does it not work well with glasses?

It does work fine with glasses in my experience.  I think it just slipped Don's mind.  He uses one with glasses, so that's about as much proof as I need.  I found the 17mm and 12mm NT4s to also work with eyeglasses, but they had such finicky exit pupils once the field stop popped into view that they were too tiring to use, so I replaced them with the ES-92s.

10 hours ago, LDW1 said:

I think you will find that UHC’s are designed to enhance some types of nebulas but may help other objects but their colors will be thrown off with dimmer views.

The nebula colors tend to remain similar (still pretty much gray), but the surrounding star colors get a wonky red/green color to them that some people find very distracting.

5 hours ago, jonathan said:

I find that even if I can get a decent view with my glasses on, that I'll then often be left with smudges on my glasses from the experience.

Carefully clean off all face grease from the top of the eyepiece, generally a folded down eyecup, and you won't have this issue.  I never swap between glasses on and off with the same eyepiece because I know I'll get smudged eyeglasses.

Try putting anti-vibration pads under each tripod foot to reduce vibration dampening time.  It won't do anything for slop in the mount or focuser, though.

Try shining a bright light on a white piece of paper and stare at it for a while to activate the cones in your fovea and to constrict your iris before looking at Jupiter.  It might help decrease the image blow-out you're seeing.

27 minutes ago, John said:

It could go on and on, there are the Nikon Nav HW's and Docter 12.5mm which are reported to be a step up again from the Ethos in performance

And the TV Apollo 11.

Got to stop somewhere though !

 

 

And ZAOs at the short end along with Zeiss surgical microscope eyepieces for binoviewers.  There are even the unobtainium Zeiss professional observatory monocentrics of which only a handful were made and delivered to observatories many years ago.

There's the new SVBONY zoom eyepieces getting a lot of chatter on Cloudy Nights these days.  All seem to be well thought of according to early adopter reports.  They're available in 7-21mm, 8-24mm, and 10-30mm focal ranges via ebay, Amazon, AliExpress, and the SVBONY website.  The 8-24mm is probably going to have the best eye relief for eyeglass wearers.

It's uncertain how much additional true field of view you'd gain going with the 10-30mm over the 8-24mm.  Neither is going to be particularly wide at the long end.

@John Have you noticed any eyepieces or telescopes presenting out of focus edges that used to be in-focus?  This happened to me and my 14mm Pentax XL.  I had been using it for well over a decade when I noticed the edge didn't focus at the same point as the center about 6 years ago.  That was also about the same time I had to start wearing bifocals and computer glasses full time.  I was perplexed by how I had never noticed it before until I realized it was my eyes that had been compensating for the FC all those years.  I was a bit crushed realizing what I had lost.  Now I had to use flat field eyepieces in flat field scopes.

Photographic ND filters are rated by stops of darkening.  Thus, an ND13 should pass 1/(2**13)=1/8192 of the original light.  These are typically used for solar imaging.

A mislabeled ND filter could be very dangerous.

4 hours ago, Alan White said:

But are they just tales or reality?
I have read such varied opinion on the XW 14 and 20.

Because it depends on your visual accommodation.  If your eyes are young, FC is not a big deal.  If you're old and suffering from presbyopia, it becomes an annoyance.  People really need to specify whether or not they suffer from presbyopia before commenting on FC.  This is true for both eyepiece FC and telescope FC.

1 hour ago, globular said:

How about I give you $325 for yours? 🤣

72ED is food for thought.  I've had plenty of times I wished I had more sky at my eye - but there is so much more to enjoy I'm in no rush to go multi-scope..... yet.  Would a plan to add this at a future date change my EP choices now?  It seems to me that the ones I'm considering would work well in the 72ED too? Except weight perhaps?

Yeah, I don't think so on the 22mm NT4. 🤨 It took me years to find one for $260 shipped.  I had been using the 22mm AstroTech AF70 quite happily for years before that.

I was thinking the wife would like to have a scope to look through while you're locating targets in the Edge HD.

Heavy eyepieces do tend to want to make a 72ED turn turtle.  You have to rig up a counterweight at 90 degrees to the scope to counteract the heavy eyepiece at higher altitudes.

Otherwise, the eyepieces work well in the 72ED.  You will notice field curvature due to the short focal length.  I ended up adding a TSFLAT2 field flattener to the front of the 2" diagonal to flatten it out.  The other issue is you have to have an altitude lock on the mount to keep the scope on target during heavy eyepiece swaps.

Focal extenders don't increase magnification very much with increasing working distance, so they would tend to continue to yield their rated magnification when used ahead of a binoviewer.  Since they are made up of two sections, the negative Barlow section below and the positive section above it to parfocalize the diverging rays, the nose piece alone would most likely be negative only.  I would try it as-is ahead of the binoviewer.

I have the 22mm Nagler T4 as well.  It's very nice, but a bit tight on eye relief compared to the others you have listed.  If you can pick up one used for about $300 equivalent, it's a good deal.

You'll find you'll either leave the Powermate in or out, but not continuously swapping it.  Thus, it's not really that useful for filling gaps.

The 17.5mm Morpheus is another option if you want to stay light and less expensive.  I've thought about picking up one for this reason.

I still recommend budgeting for a 72ED on an alt-az mount for 11x to 62x powers.  I really enjoy cruising star fields and observing clusters and asterisms that are too big for long focal length scopes.

I couldn't handle my 14mm Pentax XL's field curvature once I got presbyopia, so I replaced it with a 14mm Morpheus that has way less.  It's not quite sharp in the outer 15% of the field due to slight astigmatism and field curvature, but it's much more engaging with its measured 77° AFOV.  I've read that the 14mm XW suffers from the same field curvature as the 14mm XL, so you have to weigh that if your eyes are fixed focus.

That said, I rarely use any 14mm eyepieces because my 12mm ES-92 is so much more engaging than any of them and covers a larger TFOV.

I have thought about trying the Hi-FW, but it would be a niche player for use when I want to strictly stick with 1.25" eyepieces.

You do realize that exit pupils below about 0.5 are rarely usable?  As such, I would forget about the Powermate.  I would put that money toward a 72mm ED refractor and mount so you can observe wide fields that your 8" SCT can't come even close to revealing.

The 10mm and 12mm are fairly close.  I would probably substitute the 9mm Morpheus for 226x.  Mine seems to work about as well as my 10mm Delos.

I don't see much if any reason to go above 306x with your scope, so the 7mm Pentax XW should be fine for nights of exceptional seeing.

I have the 30mm APM UFF and both ES-92s.  You'll really like them.  The 40mm Pentax XW should be very good as well, although I have no personal experience with one.  I use a 40mm Meade 5000 SWA (Maxvision) at that focal length.

For the ES-92s, I'd check to see if you'll need to add some sort of counter balance to avoid overworking the mount.

On 19/09/2020 at 08:32, popeye85 said:

Cheers. What about a ultra wide field ep?

As in ultra wide true field of view?  You didn't specify the focal ratio of the 12" Dob's mirror.  Assuming an f/5, that would mean 7*5=35mm would be about your longest focal length based on maxing out your exit pupil.  You could go with a 30mm ES-82 or 31mm Nagler T5.  The 35mm Aero ED won't be as well corrected at f/5, but it will present a slightly wider TFOV and be much lighter and cheaper.

On 19/09/2020 at 04:08, sputniksteve said:

I've recently bought a used Skymax 127, and even with the mediocre eyepieces* that I got with it, the view of Saturn feels better than it ever did with my 12" Lightbridge - even with the 7mm Televue plossl that I used to own (and stupidly sold with the Lightbridge). I acknowledge that it's some years ago that I last looked through the 12", and my eye is probably better trained now too.

*There's a 12.5mm one labelled as Series 500, but no manufacturer. With the stock barlow, this is producing a nice view of Saturn. I can't wait to get hold of a good eyepiece!

That 12" must have been miscollimated or had a terrible mirror.  My most memorable views of Jupiter were through a 12.5" Mag1 Instruments PortaBall with a Zambuto mirror on an Osypowski equatorial platform at a star party.  I could make out all sorts of festoons and barges in the belts with ease.

At f/12, I wouldn't go much below 7mm to 8mm because the exit pupil becomes 8/12=0.67mm to 7/12=0.58mm which is really pushing it for most people.

I would start with the 8mm BST Starguider and the 7mm SW Planetary for 188x and 214x, respectively.  See how they well they work for you and go from there.  I have found the 8mm BST to be a very good eyepiece.  It's not Delos or Pentax XW good, but it's not that far behind despite the price difference.  I have never even so much as looked through a TMB Planetary clone, of which the SW Planetary is one, but I've read that many find them to perform quite well.  You might even want to consider the 9mm SW Planetary instead of the 7mm to back off the power a bit to 167x when conditions won't support 214x.

Generally, Barlowing binoviewers works really well because it helps to reach focus in telescopes with limited in-focus travel, slows down the light cone, and seemingly makes merging high power images easier than when using pairs of short focal length eyepieces.  Even with SCTs and Maks that can natively reach focus with binoviewers, Barlows allow the telescope to operate much closer to its designed focal length which minimizes induced spherical aberration.

All in all, Barlows play really nicely with binoviewers.

I did one thing right starting out 23 years ago.  I attended public star parties for 2 years before deciding on the type and size of telescope I wanted to use.  That was a 6" to 8" Dobsonian solid tube telescope.  I was even looking through 4" Astro-Physics refractors on really nice mounts, but I was completely unimpressed by them compared to the bigger Newts.  SCTs of the day seemed to put up really mushy images aperture for aperture compared to their Newtonian counterparts.  They all couldn't have been out of alignment.  No one was observing with Maks or traditional Cassegrains back then that I can remember, so those were never considered.  I also realized nudging to track wasn't that big of a deal.  Neither was learning the sky via sky atlases and star hopping.  There were a few fledgling planetarium programs out there, but there were no smart phones or tablets to use them on while observing.  Vastly expensive laptops were the only portable electronics option, but I didn't have one and couldn't afford one, either.  I also realized I needed long eye relief eyepieces that work well at f/6, so I bought Vixen LV and Pentax XL eyepieces and skipped the whole eyepiece upgrade treadmill.  Vixen LVWs and long focal length Panoptics were about the only other well corrected, long eye relief options back then.

There are so many more high quality options today at much lower inflation adjusted prices that folks starting out today don't even realize how lucky they are compared to the situation just 23 years ago.  I can't even relate to those who started out in astronomy in the 1950s to 1970s.  Everything seemed so rudimentary and yet so expensive at the same time based on the ads I've seen.

The equation for Barlow magnification is M = 1 - L / f_b where L is the distance from the Barlow lens to the eyepiece's field stop and f_b is the Barlow focal length (always a negative number for magnifying Barlows).

Regardless of the Barlow focal length, which is never reported by any Barlow makers to my knowledge, it is clear that increasing the working distance between the Barlow lens and the eyepiece is going to increase the magnification.  That's why using Barlow elements in front of a binoviewer generally yields more magnification than when the Barlow is used as designed.  This assumes that the Barlow had a shorter working distance as designed than the optical path length of the binoviewer.  There are vintage long Barlows for which this might not be the case, but they didn't generally have removable lens cells.

If quality, low cost ED refractors had been available in 2000, I would never have bought my ST80.  Horrible purple fringing and spherical aberration along with a mediocre focuser.  I had hoped it could double as a spotting scope, but the haziness of the view was more than I could take.  In the end, it has sat mostly unused in the closet for 20 years.

I ended up paying about the same 13 years later in inflation adjusted dollars for my used AT72ED which blows the ST80 out of the water in every way except weight.  I actually paid much more for my ST80 in 2000 than they sell for new today!

2 hours ago, NVDW said:

Ok so no response from the German company. Tackled it myself today. After a lot of sweat and nerves.... 1 speckle of dust left between the elements lol. Really wanted to start over but let's not tempt fate haha.. Mild OCD over here

At least it looks great if you want to sell in on. 😙

23 hours ago, Second Time Around said:

This is because you can dial in the exact best magnification for a given object in given seeing conditions. 

Doubly important when using binoviewers because you're trying to swap two eyepieces at a time and trying to avoid letting them tip in the collets due to undercuts.

2 minutes ago, globular said:

Is there a "correct" or "ideal" position for the focus knob to be before tightening and locking the mirror for transporting?  All the way in? All the way out? Not important?

I've never heard that it matters, just don't overdue it when tightening them.  Hopefully a few others with more knowledge than I in this area will chime in.

Given the tight supply constraints on new telescopes and mounts right now, you'll probably have to start out seeing what's available from various dealers such as Astronomics up in Norman, OK.  I know that would just kill a true Texan to buy from a Sooner retailer, though. 😄 They do sponsor Cloudy Nights forums like FLO sponsors SGL here.  There's also Agena Astro, OPT Telescopes, Orion, Skies Unlimited, High Point Scientific, and several others.  I would avoid the NYC mega-retailers because telescopes are just a side business for them, and they have very limited expertise with them.

For what you want to look at, a computerized mount might just get in the way.  You would probably want to stick with an alt-az (up-down/left-right) mount for whatever telescope you end up purchasing.  I would avoid a fast (short/low f-ratio) achromatic refractor.  They generally have loads of color fringing and spherical aberration.  A slow (long/high f-ratio) achromat can become a bit unwieldy for terrestrial use.  A smallish Mak or SCT might suit your needs well.

Really, it comes down to your budget, storage room, ability to transport, observing site restrictions, etc.  Ideally, a fast 4" apochromatic refractor might serve you well, but might also be too expensive.