Louis D

9 hours ago, vlaiv said:

Problem is of course that I keep reading: "It is ok in F/7" and "It is not good even at F/7" - all over the place . I'm fairly sure it will be acceptable at F/10, and I'm also aware that Aero ED will be better corrected - problem of course being that Aero ED is no longer available in 40mm FL - only 35mm and that has 10% smaller FOV if I'm not mistaken - about 42-43mm, right?

I've measured my 35mm Aero ED to have a 44.4mm field stop.

4 minutes ago, John said:

Maybe your 36mm Baader Aspheric is better than the one that I had ?. I was rather shocked to see astigmatism in the outer field in a 150mm F/12 refractor I must say

I never said I own a 36mm Baader Aspheric, but based on everything I've seen and read online, it performs similarly to the 35 Aero in that it is an improvement over the Erfle design, but not corrected to the level of a Panoptic or XW.

8 hours ago, John said:

Having owned a 36mm Baader Aspheric and not found it brilliant even at F/12, I'm a little surprised to read this. The 40mm Aero ED is certainly a much better corrected eyepiece than the Baader Aspheric IMHO.

I was comparing the 35mm Aero extensively last night against other, much better corrected widest field eyepieces such as the 40mm Meade 5000 SWA, and it was pretty poor on the moon in the outer 30% at f/6 even with a CC in comparison.  From online images I've seen, the 36mm Baader seems to be similar.  Even in 2x Barlows, the 35mm Aero would not clean up very well in the outer 20%.  I just didn't want the OP to buy one and be disappointed with it in his 14" Newt.  It would probably be fine in a f/12 to f/15 Mak, though.

The 35mm Aero isn't going to be much, if any, better than the 36mm Baader Aspheric.  The older 35mm Baader Scopos is significantly better, but narrower.  It's also heavier than the 12mm ES-92.

Mine looks identical to this one since I bought mine in 1998:

I didn't notice any significant change to the exit pupil of either ES-92 when using this Barlow.  However, the shorty GSO ED Barlow made blackouts due to kidney beaning a bit more prevalent in the 12mm.  Screwing the GSO ED optics section onto the 12mm made matters even worse.  However, I was still able to use them.  I did try the notoriously SAEP riddled 26mm Meade MWA, and SAEP also got worse with GSO ED Barlowing.  I never noticed the eye relief getting longer with any of them, just SAEP getting worse.  It seems that long Barlows are gentler on SAEP than shorty Barlows, perhaps because the rays are not diverging so strongly as they enter the eyepiece.

I forgot to mention that you can't always use a long barlow on a telescope that uses a diagonal unless it has a lot of in-focus available because they have to be inserted 4 inches or so and then the focuser needs racked back out about 1.5 inches.  Thus, it needs inserted about 2.5 inches to maintain focus position.  That means that if you can only insert it about 1.5 inches into the diagonal, you'll still need at least another inch of in-focus, perhaps much more.  On a Newtonian, this is not an issue.

I also forgot to mention that screwing the GSO ED Barlow onto longest focal length eyepieces truncates the outer 25% or so of the field.  It's not a sharp cutoff like with the Orion.  Instead, it rapidly fuzzes out.  This is the same effect I see when using the Barlow section that came with my 20mm/30mm Agena 80°, so I never use it that way.  I've never even done a photo test through it in that configuration because it's so bad.

On 18/11/2020 at 18:26, globular said:

I’d be interested to hear how they perform.
I’m still new to astronomy and have lots of gaps in my EP line-up.
I’m wondering if a 2” 1.6x or 1.5x would help fill some gaps while EP stocks are so low.
I’ve tried a 22T4 with a powermate 2x and it works really well. Would the Antares 1.6x and / or the nosepiece of the GSO ED (giving 1.5x) work as seamlessly? Or with some aberrations? They are a lot cheaper than the TV after all.
 

I tried both ES-92s in a variety of Barlow/PBI/CC combinations tonight to view the moon with my 8" f/6 Dob.  The cleanest view would have to go to the Orion Deluxe 2" Barlow.  It was simply sharp across the field.  The GSO ED 2" Barlow was close behind, but caused (or failed to mask) a bit of field curvature and slight sharpness issues at the edge.  Adding the PBI to the GSO ED seemed to flatten the field, but introduced edge aberrations of some sort.  With no bright stars handy, further diagnosis will have to wait.  For the longest focal length eyepieces, there was definite field truncation with either Barlow alone, but the Orion was again sharper across the field.  The GSO+PBI eliminated the truncation, but the image wasn't as sharp across the field.

Adding the GSO CC into the mix (between the eyepiece and either Barlow) did nothing to sharpen the image of the Orion Deluxe with the ES-92s.  I would say the image was much better without it.  Results were similar with the GSO ED.  However, adding the GSO CC to either Barlow eliminated the field truncation seen with the longest focal length eyepieces.  It was acting a bit like a PBI, apparently.  I was undecided if the GSO ED + PBI was better than the GSO ED + GSO CC with longest eyepieces.  Going GSO ED + PBI + GSO CC would seem ideal, but again, the results were mixed with longest eyepieces and downright bad with the ES-92s.  I think there's just too much glass and too many interactions going on.

Screwing the GSO ED lens element directly onto the bottom of every eyepiece resulted in a sharp inner 50% and a dreadful outer 50%.  Literally all eyepieces turned to a blurry mush that couldn't be refocused in the outer 50%.  Highly NOT recommended.

My recommendation for the ES-92s would be to try to find a Japanese made Orion Deluxe 2" Barlow if you have a Dob and skip adding a CC to it for use with the ES-92s.  Barring finding the Orion or another vintage long 2" Barlow, the GSO ED is a decent alternative.  I'm not sure how much improvement a genuine TV Powermate would yield as I could see no significant image degradation introduced by the long Barlow.  There was a tiny bit introduced by the shorty GSO ED Barlow around the edges.  It was a subtle difference.    The 12mm ES-92 in particular did best with the Orion alone.  Adding either the PBI or GSO CC to the GSO ED led to less sharpness, so less is more in this case.  The good thing is that these Japanese 2" Barlows turn up for decent prices every once in a while on the used market because they are relatively unknown to today's astronomers.

For longest focal length eyepieces, the GSO ED + PBI worked best across the field and eliminated field truncation best.  However, central sharpness was again best in the Orion Barlow.  The gentler lens curves of the long Barlow seem less demanding on eyepieces even when a PBI was added to the GSO ED.

None of the combinations resulted in terribly finicky exit pupil issues.  The GSO ED, though, seemed to introduce more than the Orion, even with the PBI in place.

For improved edge of field performance at higher magnification and reasonable weight, you might try to pair the 40mm Pentax XW-R at 667g with a 46.2mm field stop and the 30mm APM UFF at 548g with a 36.4mm field stop.

3 hours ago, globular said:

Most houses on our road face the road directly and are clearly displaying their number.  Others, of which ours is one, are set back down long driveways, so we do take a bit more seeking out.

Most houses down long driveways in the US have mailboxes at the street/road with the address on them:

Even in the city, this is fairly common:

Ever thought about putting your mailbox out at the street/road?

On 21/11/2020 at 07:12, globular said:

I'm after an ES92/17 (some of you may have noticed ) but the retailers won't give me the time of day.

On 20/11/2020 at 07:27, globular said:

Update:  I've found it! 

I decided to walk the streets in the rain to see if anything had been left on anyone's doorsteps and, amazingly, I both found it and didn't get reported for furtive behaviour. 

Very poor by UPS to leave it where they did - but I'm just happy I've got it at last.

We get our USPS deliveries to a common mailbox area at the back of our neighborhood.  Our postal workers are always misdelivering things to us.  Our local post office gets 2 out of 5 stars on yelp because of it.  I try to get deliveries done by anyone else when possible.

As an example of their incompetence, I had over $1000 worth of jewelry supplies (another hobby of mine) delivered, but not to me.  I was having a panic attack over it.  None of my neighbors had seen it, so I waited for the postman to reappear the next day and made him check the neighbors' boxes with me.  Sure enough, it was delivered to the neighbor one street over with the same house number, and they hadn't yet picked up the day before's mail.  The postman explained they use substitutes around the holidays who are completely clueless, and it was the day after Thanksgiving when it was delivered.  Perhaps that's what UPS is doing in your area.

Our PO also marks items as delivered just to meet on-time requirements when it fact they have not been delivered.  In reality, they show up anywhere from 1 day later to never.  However, you can't claim a lost package when the PO says it's been delivered.  You can start a package trace, but that never turns up anything when they're trying to cover their lying behinds.

By comparison, UPS, Fedex, and Amazon are generally 100% accurate with their deliveries in our area; so I'm very surprised by your experience.

On 19/11/2020 at 14:28, HollyHound said:

One issue I did encounter, was that (of course) the Pentax XW30 is quite a bit heavier than all my other eyepieces and so the dob became nose heavy when lowered to around 40 degrees.

Maybe you asked about 30mm eyepieces on here before ordering, but I don't recall that you did.  Had you inquired, I would have recommended the 30mm APM UFF over the 30mm Pentax XW.  The UFF is lighter (548g vs 740g) so no balance issues, smaller in diameter, sharper to the edge as far as both astigmatism and chromatic smearing, completely flat of field, lower in distortion, and lower in cost.  The only downside is no adjustable eye cup, which I haven't read of anyone complaining about.

Here's an excellent comparison of the edge correction of each.  I've linked the images below:

30mm Pentax XW:

30mm APM Ultra Flat Field:

Agreed, it looks much bigger on the horizon than it does high up in the sky (at least from here in Texas) later in the season.

Let's say you want to stop at 0.5mm exit pupil, that would be 130mm/260x or a 650mm/260x=2.5mm eyepiece.  This power would mostly be useful on the moon and for double star splitting.  For planets, I would back off to no smaller than a 1mm exit pupil with a 5mm eyepiece to maintain decent, though not exceptional, contrast.  This equates to 130x.

The 5mm BST Starguider is a very good performer for not a not of money.  I'd start with it and see how you like it.

6 hours ago, globular said:

Still can't find a 17mm anywhere though

I found them in stock at multiple places in the US (Agena, OPT, Amazon, High Point, possibly others).  How badly do you want one?

1 hour ago, Dario said:

I had to test it from home through a window

1. Hopefully, you at least opened the window.  Viewing through windowpanes is a recipe for blurriness at high powers.  They are going to be far from planar at the wavelengths of visible light causing distortion like a bad lens.

2. Hopefully, the inside and outside temperatures were close.  Otherwise, you're going to get thermal gradients as air rushes through the window to equilibrate the temperature differential.  Those thermal gradients will act like lenses distorting your view.

3. In summary, if you're going to view from inside through a window, open it wide open and allow the temperature inside to reach the outside temperature before observing.  Perhaps running a box fan in the window temporarily would hasten this process.

58 minutes ago, Armand Popa said:

did anyone compared a Skywather planetary to a TS planetary. 

Both of them are TMB designs, am I right?

I have a TMB planetary II, 2.5mm chine clone, but I am very pleased with it. It has good image and is is well corrected at the side of the field.

I want to buy a 3.2mm one but I am stucked at the differences between Skywather (5 elements) and TS (6 elements)

Thanks!

 

I'm assuming you've already read this comparo, but it case you haven't:

Other than it, I don't know of any detailed shootouts across Planetary brands.

3 hours ago, John said:

The Antares 2 inch 1.6x barlow works well with the Ethos's - perhaps it would well with the ES 92's as well ?

 

If you've got both, give it a try sometime and let us know.

I'll try the GSO ED alone sometime with the ES-92s to see what happens.  I also have an Orion Deluxe 2" 2x (Japan) that's 6" long I could try.  I could even thread the GSO ED optical nose piece onto the end of the ES-92s for grins.

56 minutes ago, SmokeyJoe said:

Just playing about, took a couple of pics at very fast shutter speed of the quarter moon last month at the end of a DSO session and it was very over exposed on the edge of the sunlit half.  Didn't think about dropping down the ISO, not used to proper cameras. 

The full moon is no brighter than f/16 at 1/125s at ISO 100.  Let's say you're shooting with an f/5.6 telescope.  That would be 3 stops faster which would necessitate either ISO 12.5 or 1/1000s shutter speed, or some combination of the two.  Perhaps ISO 50 and 1/500s.  It depends on the ISO settings available in your DSLR.

High shutter speeds are your friend in this case because they will mask mount vibrations and reduce atmospheric blurring.  In fact, some astrophotographers will take hundreds to thousands of video frames, select the best, and stack them with specialized post processing software to create ultra sharp images.

To get the earthshine illuminated half will require a vastly slower shutter speed and/or higher ISO.  You would then need to composite the two images (dark and bright parts) in post processing.

1 hour ago, rkelley8493 said:

Aw man 😧  That's crappy news.. I was hoping they'd release an 8mm 92° to fill a void I have with this focal length. I'd be more likely to purchase a new ES 8mm 92 than I would an 8mm Ethos, but it looks like I may not have the luxury 😕

The APM XWA is available in 9mm and most recently, 7mm, focal lengths.  Yes, not exactly 8mm.

Have you tried the 17mm ES-92 in a telecentric magnifier?  I have with my 2" GSO ED 2x Barlow and TV PBI, and it works really well, as does the 12mm ES-92.  It does make for a very long and heavy optical stack, though.  I'd recommend it only for Dobs with stout focusers.

A Barlow will increase magnification and exposure time.  It will also spread out the image circle, decreasing vignetting relative to no Barlow, assuming you use a 2" Barlow.  I'm not sure about vignetting with a 1.25" Barlow and a DSLR.  It would depend on the sensor size.

I'm not sure why you would want to put a moon filter in front of your DSLR.  Just use a higher shutter speed or lower ISO instead.

Not clear if it has been discontinued in the US.

3 hours ago, michael.h.f.wilkinson said:

Absolutely, My Nagler 17T4 might be the next to go

The 17mm ES-92 is, if anything, even nicer than the 12mm in that it is slightly sharper to the edge and slighter flatter of field.  It also has a slightly easier exit pupil to hold as @John reports above.  It is definitely one of my favorite eyepieces to use every time I observe mid-sized objects.

2 hours ago, Fozzie said:

i thought i'd read some where shorter lengths in the range in the future..

@Don Pensack reported on CN that ES told him in 2016, and I quote:

"Learned today there will be an 8.8mm , a 6.5mm, and an, as of yet, unspecified focal length in the series appearing in 2017."

So don't hold your breath waiting for them. 😆

I don't have the 31mm NT5, but I do have the 30mm ES-82.  By my scale, I get the following weights:

30mm ES-82 (original mushroom top) : 973g (decloaked), 1369g (with cloaking eye cup)

17mm ES-92 : 1153g

12mm ES-92 : 1011g

Tele Vue eyepiece specifications page lists the 31mm NT5 at 998g

So, the 12mm ES-92 is just about identical in weight to the 31mm NT5 and 142g lighter than the 17mm ES-92.

The 31mm NT5 is just about the same weight as the decloaked 30mm ES-82.

The only other eyepiece that I use which weighs over 900g is the 35mm Baader Scopos Extreme at 1072g.  I have a feeling its weight and bulk doomed it despite really excellent performance for its price.

I ended up buying an alt-az mount with axis locks (DSV-2B) to facilitate heavy eyepieces changes.  At a star party I attended, even the DM-6 struggled during heavy eyepiece changes without axis locks.  The owner had to keep a finger on the diagonal during changes to keep it from nosediving.

It's a pretty sweet eyepiece, isn't it?  I'm just hoping for a 22mm to 24mm version to replace my 22mm NT4 someday.