Louis D

1 hour ago, Philip R said:

I see they accept an AMEX payment... "That'll do nicely!"

Was there ever a British Express equivalent?

8 minutes ago, johninderby said:

Eye watering prices on the 4” and 4.3” diagonals. 🙀

https://www.siebertoptics.com/SiebertOptics-eyepieces-observatory.html#2.7

But when you've just dropped 100+ large just on the optical tube assembly for an observatory class instrument, those numbers seem like peanuts.  They're mostly used for observatory outreach events since almost all professional astronomy is done using instruments these days.

1 minute ago, JenkoRun said:

As a trainer? I could probably find something off Ebay that I can afford for that... Provided we get a clear night sky anytime soon >.<

Yes, because you're going to find that it is difficult to get your object centered, to track it well at higher powers, and to focus it sharply, among other issues.  It's best to hone your skills at lower powers and gradually refine them to move to higher powers.

5 minutes ago, JenkoRun said:

*Whistles* that'll be the most expensive part I buy for this yet, thanks for recommending it and the advice you provided, cheers!

Then I'd start with lower cost 2x, 3x, and 5x Barlows to learn the ropes, so to speak.

There are also 3" eyepieces like the 30mm ES-100 and Siebert makes 2.5", 2.7", 3", 4" and 4.3" eyepieces for observatories.

1 hour ago, John said:

As the photo says, the .965 inch ones are not available new now, as far as I'm aware:

I just picked up a cheap 70mm aperture, 300mm focal length telescope to turn into a finder scope for kicks, and guess what?  It came with two 0.965 Huygens eyepieces, a 20mm and a 6mm, so they're still out there being produced for inclusion in cheap telescope kits.

54 minutes ago, MrGuGuZai said:

i tend to do some imaging, is the dobsonian mount hard to do imaging? 

You can hold a smartphone camera up to the eyepiece and get snapshots of brighter objects like the moon and planets and, with a proper solar filter, the sun.  If you build or buy an equatorial platform for it, you can extend the imaging opportunities somewhat.

10 minutes ago, JOC said:

but if you look at it from mirror size they are more than linked - following that argument the larger mirror allows a larger exit pupil and from what I gather the more faint the object the more advantageous it is to view it through a larger exit pupil as more light will hit the optic nerve.  i.e. the larger mirror permits you to increase pupil size you need to see faint objects.  It seems to me that whether you look at the larger mirror as something that gathers more light or something that allows a larger exit pupil its all about being able to see the more faint objects which need more light to hit the optic nerve.  Thus supporting my statement that increasing the size of the mirror appears to be a means to an end to see more faint objects (even if by dint of this you are doing so by increasing the possible pupil exit size that can be used).

A larger scope will not necessarily improve the ability to detect an object if the magnification at the optimal exit pupil becomes too high.  An example of this would be Barnard's Loop.  It wasn't even discovered until the advent of photographic plates because it's too large and diffuse to detect with the eye in pretty much any telescope.  Had it been 100 times farther away, it might have been detected earlier.  However, Barnard's Loop is easy to detect with night vision gear and a low magnification lens.

I would probably consider using a Tele Vue 5x Powermate for high magnification work with the above 1.25" adapter and T-ring.

Have you tried focusing it during the daytime on a distant object?  Have you twirled the focuser knob all the way from one end of travel to the other?  If you can get your DSLR to come to focus consistently, remove the DSLR and replace it with an eyepiece (even if just handheld) with its shoulder in approximately the same position as the camera's sensor.  You should be able to move the eyepiece in and out a bit and get a focused image as well for it without touching the telescope's focuser knob.  If you can, that's one possible way to use the scope, though it may negate the use of a diagonal and require an extension tube of the proper length.  I'm concerned that your moveable mirror isn't moving properly to bring the telescope to focus.  Hopefully, that's not it.

I would hope you've tried observing with eyeglasses that correct your astigmatism to see if that improves your low power views.  If you don't have eyeglasses to correct your astigmatism, you need to get a pair.  What you've described is exactly what astigmatism of the eye looks like.

8 hours ago, Gary1975 said:

My daughter (9)  and I are interested in starting astrology.

Well, if you're interested in astrology, I found a couple of forums dedicated to the subject.

However, if you're interested in astronomy, then you've come to the right place.

While you can connect some scopes to a phone or tablet, you'll be paying about 60% or more of the price for the electronics rather than the optics or mount.  If you want to go down that route, I was impressed by the Celestron Nexstar Evolution 8 HD at a star party a couple of years ago.  A rank novice had bought it and easily set it up, aligned it, and wirelessly connected it to his tablet.  He could navigate around the sky on the tablet, select an object, and the mount would slew to the object and keep it centered.  The optics were superb as well.

Let us know what your budget is so we can better align our recommendations.

Eyepiece projection doesn't generally produce very good results because very few eyepieces project a flat field, so only the central part of the image will be in focus.  Microfiche lenses reportedly did a good job.  Pentax made a small line of specialty projection eyepieces years ago (the XP line), but they are rare and expensive.

I would stick with prime focus, prime focus with a Barlow, or afocal projection.  For the first two, you'll need a 1.25" to T-thread adapter and a T-ring for your particular camera's mount.  For the afocal method, there are various adapters to try and facilitate aligning the camera with lens to the eyepiece.  However, I've found it difficult to get the large lenses of DSLRs to play nice with eyepieces.  Cameras with small lenses like smartphone cameras work much better for this method.  This adapter gets good reviews for this purpose.

Moving up from 6" to 8" won't be nearly as noticeable difference moving from 6" to 10".  Try it for yourself on your 6".  Create a circular mask with a 4.5" diameter opening and put it on and off over the front of your scope while observing different objects.  This is the same step difference as moving from 6" to 8".  Now repeat the same experiment with a 3.6" diameter mask.  This will demonstrate the 6" to 10" step to you.  Make sure to consider the weight and bulkiness increases in moving from 6" to 8" to 10" before any purchases.  Also, each step up results in a shorter focal ratio, so each will be more and more demanding on your eyepieces in terms of edge correction.  On the 10" in particular, you'll probably want to invest in a coma corrector to make the outer edges of wide field eyepieces more acceptable.  If you only use 50 degree or less AFOV eyepieces, you might be fine without one.

4 hours ago, JOC said:

For me 'Exit pupil' is not a tangible 'something' I can't think in those terms and tbh just take what I am told at face value when folks go on about it.

All I can say to make exit pupil tangible is to point your scope at something bright like the sky and pull back from the eyepiece and notice how the illuminated spot shrinks with increasing magnification.  If I had to guess why 2mm is the sweet spot, that's the size of most people's irises in the daytime, so that's where your vision has adapted to having the best acuity over time.  As far as why tiny exit pupils are uncomfortable, it's like a pinpoint of light shining into my eyeball illuminating every floater individually in there.

3 hours ago, Maniek said:

I also have Morpheus 9mm and I'm a bit disappointed with it. It's a cold and tight compared to ES😏.

I get the same feeling moving from the 17mm ES-92 to the 14mm Morpheus to the 12mm ES-92 power progression.  Despite the 76 degree field, the Morpheus still feels constrictive in comparison to the two ES-92s.

2 hours ago, merlin100 said:

My hitlist  will include a 25mm Plossl, 9mm or 10mm Plossl, a decent 2x Barlow and lastly a 30'ish mm 2 inch EP for wider views. 

The 25mm Revelation Plossl would be a good choice for not a lot of money.  FLO's Sky-Watcher SP Plossls may also be GSO made.  If so, they have a 10mm version.  However, you may find that you'd prefer using a 20mm or 25mm with a 2x Barlow instead due to the much better eye relief.  As far barlows go, since you're using a Dob, you can use a long barlow.  I've compared various vintage Japanese made Barlows: Tele Vue 2x, Meade 140, and Orion Deluxe, and the Orion is just slightly sharper than the rest, though it is the longest at about 6 inches, so not a big surprise.  I see it still in stock over in the UK.  Just confirm it's new old stock and marked Japan made.  It is actually a 2.1x Barlow like the Tele Vue.  The Meade is a 2.4x Barlow.

3 hours ago, Paul73 said:

ES92°? That is interesting.

What scope do you use it with?

An 8" Dob, a 72ED and 90mm Triplet APO normally.  It is tricky to balance on the 72ED when viewing near zenith (it wants to turn turtle), and it can cause the Dob to sink when viewing below about 35 degrees elevation.  However, the immersive views are so worth it.  I have strong astigmatism in my observing eye (2 diopters), so I need to wear eyeglasses to avoid spiky stars at anything above 1mm exit pupil.  Thus, my options for wide fields above 76 degrees become extremely limited.

Here's photos of and through my various ~17mm eyepieces for comparison sake.  The Morpheus and Delos will be fairly close in size to the AF70 and Nagler T4.  It also gives you an idea of how much additional apparent and true field you get by jumping up from 60 to 70 to 82 to 92 degrees.  The views always try to put the end of the rulers at the right edge, so the distance shown on the left edge corresponds to the true field of view governed by the field stop independent of edge distortion.  Based on these values and the known field stop values for the Nagler from Tele Vue and ES-92 from Explore Scientific, I get 19.5mm, 22.3mm, 24.2mm, and 27.4mm moving from left to right and top to bottom.  The "full view" images were taken using an ultrawide angle but lower resolution camera and then scaling the result to match the central magnification of the narrower angle but higher resolution images above them.  The small edge images were taken with the higher resolution camera pointed at the edge to reduce artifacts introduced by the camera lens.

1 hour ago, Paul73 said:

Thanks John

I don’t wear glasses to observe and would struggle to hold a hovering eye position. Whereas I know that I can observe all night comfortably with a Delos.

Paul

Do you raise the eyecup sleeve of the Delos to view?  The ES-92 actually has slightly less usable eye relief than the Delos (17mm vs. 18mm).  If you don't raise the eyecup, it would view pretty much the same.

5 hours ago, JOC said:

The only thing is the Morpheus stops at 17.5mm and that rather misses on the wider field views of the sky, but for the sake of my bank balance that's probably a good thing and I have some lesser EP's that do serve in that capacity.

I would pick up a 30mm APM UFF to get those wide TFOVs you desire.  It views very much like a Delos or Morpheus.

1 hour ago, rkelley8493 said:

They're pretty good! I tried the 17.5 Morpheus, and it has about the same properties as Pentax XW & TV Delos. It's sort of like an offspring of the two with a slightly wider field of view.

Have you had the chance to compare it to the 17mm ES-92?  I have the 17mm AT AF70 and Nagler T4, but prefer the ES-92.  I've wondered if it would be worth it to pick up a 17.5mm Morpheus for 1.25" usage.  The AT AF70 has noticeable of chromatic aberration and astigmatism in the outer 15% of the 70 degree field, so not really a viable options most of the time.  Is the Morpheus free of aberrations at least out to the last 5%?  The 14mm Morpheus has quite noticeable field curvature, astigmatism, and chromatic aberration in the out 10% of the field, but less than the 17mm AT AF70 and way less than the 13mm AT AF70.  Still, I like the Morpheus better than my 14mm Pentax XL because of the significantly wider field.

If you like the eye relief of the Delos series, you might like to get a 12mm ES-92.  It presents a just as easy to take in 92 degree AFOV without having to hunt around to see the edges.  It's just there in front of your eye all at once.  It's also very sharp right out to the edges.  Reportedly, it's just a step or two behind the 12.5mm Nikon NAV-HW and even less behind the 13mm Ethos in overall correction.  I don't have a 12mm Delos to compare it to, but it comes pretty close to the 10mm Delos in sharpness and contrast, just with a much larger AFOV.

3 minutes ago, TareqPhoto said:

The question is, why selling?
I don't buy second hand or used, and sounds this guy has money all around so that he bought TWO FSQ and selling them maybe to buy something more expensive, not thanks, for $4800 i can save about $1200 more and buy new one completely. 

Two different sellers.  Probably newbies with deep pockets who they thought they'd get into imaging big time, but in the end found it wasn't for them, so they are dumping their little used equipment.  I see this happening a lot in other hobbies as well that have large, up-front investment costs.  Boats, RVs, motorcycles, ATVs, photography, video production, woodworking, metalworking, CNC, etc.  Folks think, hey, I liked doing that activity that one time years ago on a shoestring budget, let's get into it big time now that I'm older and have the money to do it right.  Only thing is, they're not the same people they were years earlier and their interests have markedly changed.  It's one thing to properly grow into a hobby rather than jumping headlong into one from the start.  Who would start being a rodeo bull rider at age 65 after having ridden a horse on vacation in their teens?  Yet I've see plenty of folks drop thousands of dollars on a telescope system in their 40s and beyond after having had a department store scope in their childhood only to turn around and sell it all after 6 months to a year out of disappointment and/or boredom.

About 20 years ago, I remember Jason Ware bringing his 16" LX200 to a local star party.  He used to do quite a bit of astrophotography with his.  You might want to drop him a line.

For future reference, if you are only concerned with the text in the document and not the illustrations and formatting which are what are taking up the majority of the 30MB, open the document in a PDF viewer, hit ctrl-a to select everything and ctrl-c to copy everything, open a new text file somewhere on your computer using notepad (on windows) and then hit ctrl-v to paste it all into it.  Save the file and tell it to lose any remaining formatting.  Next, compress it into a zip file.

I was able to take a 587KB PDF manual down to 27KB uncompressed and 10KB compressed with this technique.  Running the original PDF file through compression decreased it to 537KB.  PDF files typically contain illustrations and formatting information that won't compress much at all because it's already stored in a compressed format internally to the document.  It's really only the text that can be compressed.