Louis D

Personally, I find the TV 2x Barlow, Meade 140 APO 2x Barlow, and Orion Deluxe Japan 2x Fully Baffled Barlow are all color free and super sharp.  They are all medium to long Barlows and only the TV is available new.  I have a cheap, generic 2x shorty Barlow that is so bad, a friend returned it to me after I gave it to him to get him started in astronomy.  He literally didn't want to keep it because it was so bad.  It wasn't exactly cheap at $30 20 years ago.

I have a pair that came with my Lomo MBS-10 stereo microscope, and they seem decent in it.  I've never thought to try them in my telescopes, though.

11 hours ago, daslolo said:

Do you barlow each eyepiece or the nose of bino? Show me your setup.

Sorry, I don't have any pictures of my setup, but I use the nosepiece from a Meade 140 2x Barlow screwed into the front of the binoviewer's nosepiece to reach focus with a 3x magnification factor.

1 hour ago, mikeDnight said:

As Vixen HR's are currently unavailable,

Agena Astro shows three in stock and OPT shows one in stock.  It would still be best to call ahead to confirm availability.

7 hours ago, BGazing said:

+1

And then there's APM UFF 30mm for half the price of Pentax XW 30mm.

Which, per Don Pensack below, is slightly better than the XW.  It's not surprising given that the design is over 15 years newer.

7 hours ago, Don Pensack said:

+1 for the 30mm APM UFF in my f/5 scope.  I have to use glasses at this exit pupil, but correction is excellent and glasses were usable with the eyecup folded down.

It was just a little sharper and had slightly better contrast than the 30mm XW in the outer 10° of field.  I rated it equal to the 31mm Nagler except for apparent field.

It is NOT compatible with a TeleVue DioptRx, so if you need astigmatism correction, you'll need to use glasses or contacts.

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:

Not only does the UFF have negligible chromatic aberration at the edge, it has negligible distortion as well.  This agrees well with my own observations and in my test photos below:

What do expect to observe with this scope?  60mm isn't a lot of aperture to work with.  Since it doesn't have a 2" focuser, we can rule out all 2" eyepieces for breathtaking widest field viewing, which happens to be my favorite activity with my AT72ED.

For a 2mm exit pupil, which is considered the ideal observing exit pupil, you're looking at a 12mm eyepiece.  The 12mm Delos would be an excellent choice at that focal length.  My 10mm Delos is spectacular in all of my scopes.

With your 2x Barlow, you're then covered at ~6mm.

I would probably replace the 24mm Baader Hyperion with a 24mm Panoptic or APM Ultra Flat Field for better correction with widest field viewing.  Neither would barlow well to 12mm due to vignetting, so don't think about that option unless you replace the TV Barlow with PowerMate or similar telecentric magnifier.

A 3.5mm Pentax XW or Delos might be a good highest power option for you.  Another would be a 3.3mm or 4mm Tak TOE or a 3.4mm Vixen HR.  Both of the these would slightly outperform the XW and Delos on planets and double stars on the nights of best seeing at the expense of field of view and eye relief.

5 hours ago, Alan64 said:

If you can hand-hold your DSLR likewise, you can use any telescope on the planet, on a manual alt-azimuth even.

Only if the objective lens of the DSLR is smaller than the eye lens of the eyepiece; otherwise, you'll get vignetting.  Cell phone cameras work great with just about any eyepiece due to their tiny objective lenses and "fast" focal ratios which capture all incoming light bundles.

2 hours ago, joe aguiar said:

I think less 50 to 60 max

As guy above says these entry scope stay on the market for a long time.

Even decent stuff sometimes takes awhile or have to go half price 

It's the high stuff like tele vue eps that I see go with a few hours to a day or 2

joejaguar 

I'm sure that's the case, but I was trying to give the person some hope of recovering a bit of their investment.  I literally couldn't find a single example of this scope being sold recently on ebay in the US.  There was an EQ version which did sell, but no AZ versions.  Really, it's the market that dictates what something is worth.  I see lots of folks trying to sell starter scopes all over Craigslist for close to what they paid for them.  Meade ETX scopes and Celestron SCTs from the distant past tend to be the most overpriced.

1 minute ago, Don Pensack said:

+1 for the 30mm APM UFF in my f/5 scope.  I have to use glasses at this exit pupil, but correction is excellent and glasses were usable with the eyecup folded down.

It was just a little sharper and had slightly better contrast than the 30mm XW in the outer 10° of field.  I rated it equal to the 31mm Nagler except for apparent field.

It is NOT compatible with a TeleVue DioptRx, so if you need astigmatism correction, you'll need to use glasses or contacts.

For me, the more relevant question is would the $400 40mm Pentax XW be noticeable better than my decloaked 40mm Meade 5000 SWA that I picked up for $125 when they were closing them out.  It's not quite astigmatism free across the field, but it's way better than the sub-$100 modified Plossls, SWAs and Erfles I had been using up to that time.  See the last four eyepiece AFOV images below to see what I mean.

Is the 40mm Pentax XW sharp across the field like the 17mm ES-92?  Since they're similarly priced, I would hope so.

First off, what did you buy used that you didn't like?  I've had great luck buying used over the years.  Two 127 Maks, a 72ED, a 15" Dob, and a 90mm FPL53 Triplet APO, not to mention DSV-1 and DSV-2B mounts, Manfrotto 058B and 475B tripods, and dozens of eyepieces.

I would look for an 8" or 10" Dob and forget about imagining for now.  Used 8" Dobs go for under $300 and 10" under $500 usually here in the states.  Check your local Craigslist listings because you don't want to be shipping a large Dob across the country.

Aside from quick afocal snaps with your cell phone at the eyepiece, imaging gets expensive quick.  Also, the best visual scopes don't tend to lend themselves well to imaging, either.

If it has all the original accessories and wooden box and it's in great condition, scopes of this type usually fetch at least $100 in the US astro classifieds.

Since they're $120 with free shipping new in the US from Amazon, I'd guess you'd be doing good to get $65 to $75 used for one.  The problem you'll run into is that the folks who buy beginner scopes such as this one don't tend to buy used.  If this were a $1200 triplet APO, you could easily get $800 to $900 used for it because experienced observers are more comfortable buying high end, used gear at a premium used price if in excellent condition.

9 hours ago, daslolo said:

On 28/02/2020 at 08:55, Louis D said:

Decloaked 18.2mm TV DeLites are supposed to be very good in binoviewers if you don't want to go the cheapie route like I did.

decloaked?

Follow the link and all will be clear.

Wow, Soligor, now that is a blast from my past.  I remember when that brand name was used on off-brand zoom lenses for 35mm SLRs in the 70s and 80s.  Apparently, the name has been resurrected for astronomy duty.

Does the size of the out of focus blob of an object change when you spin the focus knob?  If not, @Ruud is probably right, the primary mirror has detached from the focusing mechanism.  If that's the case, you've got some scope surgery on your hands.

16 hours ago, JamesF said:

Some sort of optical sensor to give feedback on the gear rotation, perhaps?

James

Sounds like it.  The controller was running open loop and didn't know how to cope with that mode.

I've only heard of planetary imagers using 5x barlows effectively.  I've got a 3x barlow and never use it.  A 2x barlow is far more useful.  If you come across a used Meade 140 2x barlow for $40 or so, get it.  They were 1990s Japanese made 3 element barlows of fantastic quality.

Do either you or your wife have strong astigmatism in your observing eyes?  If so, you might benefit from wearing eyeglasses at the eyepiece when viewing at lower powers.  This would require eyepieces with longer eye relief.  If on the other hand neither of you have much if any astigmatism, you can get by with short eye relief eyepieces that tend to be less expensive because the lenses internal to the eyepiece can be made smaller and yet achieve the same view as the longer eye relief eyepieces.

If the ES82 series prices are too dear ($200+ here in the US), the Meade 5000 UWA are cheaper ($100+ here in the US) and tend to view very similarly.  There's also the OVL Nirvana UWA-82º eyepieces that are quite affordable, though limited in focal length selection.

The BST Starguiders and Meade HD-60s are also good choices.  I did a write up on them here.  If you want a really wide field of view at lower power with good correction in the central 50% (and strong field curvature beyond that), the generic 30mm 80º eyepieces on ebay are very serviceable for the money.

6 hours ago, Shaun_Astro said:

A 200p is great. Rock steady alt az mount, 200mm and no CA. I wonder why people spend ££££s on APOs when a £300 newt will show you much more. 

To get higher contrast and sharper pinpoints by totally eliminating the central obstruction.  An off axis reflector (or large reflector masked between secondary vanes) gets you pretty close to that experience.

Just about the only two places dust affects the view is right at the eyepiece focal plane and on the outside of the eyepiece eye lens.  Some eyepieces place a lens surface very close to the focal plane where the field stop is located up inside the lower part and any dust on it will appear slightly out of focus.  Also, reticles in centering eyepieces are exactly at the focal plane, so any dust on them is highly magnified.  Dust to a lesser extent, and general grunge to a greater extent, on the eye lens will highly degrade the view through the eyepiece; so keep the eye lens on your eyepieces clean of fingerprints and other sources of grunge.

There would have to be a general coating of dust on the primary to have any effect on contrast by increasing scatter.

2 hours ago, Astro-Geek said:

I tried that Louis, but my current contents insurer (Saga) have just answered my query that policy changes can't be made after the term has started, and the cancellation fee is £35....  ☹️    Although my sum insured is £75,000, there's a limit of £3,000 in outbuildings contents.

Definitely time to find a new insurer.  In my insuring past, both State Farm and Travelers here in the states had no trouble writing insurance riders for expensive jewelry pieces and musical instruments covering loss or damage outside the home soon after I bought them.  Maybe it's a quirk of US vs UK property insurance laws.

32 minutes ago, JOC said:

Paving the way for an intergalactic highway?

To quote The Hitchhiker's Guide to the Galaxy on this subject for those who don't get the reference:

"This is Prostetnic Vogon Jeltz of the Galactic Hyperspace Planning Council. As you will no doubt be aware, the plans for development of the outlying regions of the Galaxy require the building of a hyperspatial express route through your star system, and regrettably your planet is one of those scheduled for demolition. The process will take slightly less that two of your Earth minutes. Thank you."

"There's no point in acting all surprised about it. All the planning charts and demolition orders have been on display in your local planning department on Alpha Centauri for fifty of your Earth years, so you've had plenty of time to lodge any formal complaint and it's far too late to start making a fuss about it now."

"What do you mean you've never been to Alpha Centauri? For heaven's sake mankind, it's only four light years away you know. I'm sorry, but if you can't be bothered to take an interest in local affairs that's your own lookout. Energize the demolition beams. I don't know, apathetic bloody planet, I've no sympathy at all."

Why not just get an insurance rider for your scopes from whomever you're currently insured through?  Present your inventory and approximate replacement value to them for a quote.  Then, if you change insurers, just present the updated inventory to the new insurer for a quote.

As far as security, and correct me if I'm wrong, but isn't the Skyshed POD just made of plastic and as such would be easy to saw through a side wall with a Sawzall?  If you're out in the country, who would hear it?  Alternatively, a chainsaw would probably work even faster.  An electric one would be fairly quiet.

I use a pair of generic 23mm 62 degree aspheric eyepieces and barlow them up to whatever power I need.  No keyhole effect with them, and they're super light and compact.  Once barlowed to 3x or more, they're pretty much sharp to the edge.

Make sure your eyepieces aren't tipping in the holders due to the locking collet tightening unevenly in the eyepiece undercut.  Either use smooth barrels or mash the eyepiece into the holder tightly while tightening the collet.

Decloaked 18.2mm TV DeLites are supposed to be very good in binoviewers if you don't want to go the cheapie route like I did.

I drove 210 miles each way to pick up my 15" Dob 21 years ago.  Well worth it to avoid any potential shipping damage (and shipping charges for a 120 pound scope).  That, and I was able to weasel a 27mm Panoptic from the seller for $200 at the same time since he had no more use for it.

Let us know how you get on with the scope.

4 minutes ago, david_taurus83 said:

Bearing in mind its also recommended to stop the Samyang down to F4-F5 for better sharpness...

Which kind of defeats the purpose, it would seem, of having an f/2 lens.  Often, it's just the edges aren't sharp, so using a smaller sensor may obviate the need to do that.  In the past, I used a full frame Sigma 50mm f/1.4 lens on an APS Canon camera to photograph dance recitals without using flash.  At full frame, there was a bit of vignetting and sharpness falloff, but cropped on the APS sensor, there was pretty much none even at f/1.4.  I will admit I generally shot at f/2.5 to get enough depth of focus to have a dancer's entire body in focus front to back.  However, I would open it up to f/1.4 for poorly lit dances.