Louis D

The only concern I would have with carry-ons would be if you board late and all the overhead bins are full, and your bag either won't fit under the seat ahead of you or you're against a bulkhead with nowhere to put a personal carryon.  In that case, I've been forced to gate check my bag.  In that case, it then goes through the regular checked bag process.  The only exception I've seen are for umbrella type strollers where they'll put them by the airplane door for you to grab for transferring to your next flight.

6 hours ago, Highburymark said:

Nice Alan! First view I ever had through a Herschel wedge was with a 152mm F/5.9 - Altair I think. It should really shine in early morning and late evening, when atmosphere is steadiest, and lets you go above 200x. 

Should also cut down on thermal build-up if using a 1.25" wedge.

Makes you wonder why there is no telescope tripod mount standardization.

1 hour ago, Ags said:

I am not one to advocate experimentation with visual solar observing, but is it feasible to add an IR-block filter before the herschel wedge to keep temperatures down?

As long as it's an interference type that reflects rather than absorbs IR energy, they work fine and don't heat up in my experience.  I keep one on the front of my 1.25" Hercules wedge to block IR that is passed by the ND filter.

Here's a thread on SGL discussing this very topic:

Check the transmission graphs in this post of mine:

Basically, the more IR filtering, the better.  You don't need to unknowingly cook your eyeball during solar observing.

5 hours ago, Philip R said:

I read or heard somewhere within LHR, that baggage with ‘air tags’ are no longer permitted to placed into the aircraft baggage hold because it contains a sealed-battery.

Just did a quick google search, and the FAA and all foreign airlines now allow airtags.  Lufthansa clarified their policy in October, 2022 to allow them.  They were the lone holdout in 2022.

Whatever you take, put an Air Tag in it somewhere in the case of theft by air cargo handlers.  They mostly take electronics, but have been known to take photography equipment.  Telescopes resemble photography equipment.  Don't think putting clothes around it hides it.  Every bag is screened via X-ray scanner.  Those running the scanners tip off conspirators deep in the bowels of the airport of anything valuable looking.

2 hours ago, Sunshine said:

Now that you mention, I believe it was a 14 but it could have been 15, id have to check my list history on buy and sell, now im curious. 
 

update: you see! i am an idiot, it was a 24mm panoptic and i listed it for $165 CAD (100 pounds?) 

Ouch!  They go for between $265 and $299 used on CN classifieds today.  $165 CAD equates to $120 USD today.  No wonder you had so much interest.

Well, the galaxy looks quite nice indeed.

Too bad about the stars.  It looks like the various color layers need shifted radially.  The shift grows with increasing distance from the center.  I recall Helmut Dersch had a feature in his Panorama Tools to do just that.

My biggest eyepiece regret was buying a 21mm or 22mm Rini "wide field" starting out on a budget for maybe $20 in the late 90s (figure close to double that in today's dollars) to fill a gap in my lineup.

It was basically a 3 element eyepiece of some sort with terrible correction and maybe a 50 degree field, hardly what I would term "wide field" even as a beginner.  Then, the central lens came loose in storage within a year for unknown reasons, jamming at an angle.  It rattles around in there now.  Since the whole thing is sealed tight in thermal plastic, I can't do anything about it.  I felt totally duped on that purchase.  It's now a focuser plug.  Live and learn.

16 hours ago, Sunshine said:

I made a stupid move a few years back, bought a mint used 14mm panoptic and didn’t really care for it in my dob back then so I sold it. That’s not the stupid part, the stupid part was I totally forgot what i paid for it and didn’t bother checking its value new and ended up selling for half of what other used ones were listed for. It’s no wonder I had several interested buyers within minutes. 

Especially considering it must have been a one-off engineering-only prototype since the shortest production Panoptic was the 15mm before it was discontinued. 😉

I can't imagine what the collector's value would be.  Probably not as high as any Nagler Type 3 would fetch, though. 😁

1 hour ago, Stu said:

Because I binoview, the brightness control is very handy as I cannot easily do it using polarisers/rotating eyepieces!

Imagine the possibilities of putting polarizers on the bottom of each eyepiece and then rotating them individually so each eye sees a slightly different brightness.  I wonder if the human brain could combine the images into an HDR photograph-like semblance. 

Sounds like a winner for most beginners.  For more advanced users, it's like getting a two-fer deal.  The Starsense unit for use on more advanced scopes, and the actual scope/mount/RDF/eyepieces for beginners like your grandson.

Depends on the usage and telescope for me:

• Lumicon OIII (90s and modern versions in 2" and 1.25" respectively) for most nebula observing
• Wratten #8 (480nm cutoff and no violet) or Wratten #4 (470nm cutoff and very slight violet) Light Yellow for fast achromats to cut violet fringing for general observing
• Meade Green interference filter for best planetary/solar/lunar detail with a fast achromat, color cast be darned

Alternatively for easier to find/afford options:

• The Svbony UHC is nearly as good as the Lumicon OIIIs on most nebula except under the most light polluted skies
• Cheap, Chinese yellow filters on ebay are roughly Wratten #4 equivalents and thus cut almost all violet
• The vintage Hirsch #12A is almost exactly a Wratten #4 if you can find one
• Vintage 48mm K2 Yellow filters are exactly a Wratten #8 if you can find new old photography stock.  48mm is the same as an astro 2" filter
• #56 Green or cheap Chinese green filters only pass half as much light, but have similar bandpass characteristics to the Meade Green
• Vintage 48mm X1 Green filters are exactly a Wratten #11 Yellow-Green and have higher transmission than either of the above green filters and yet cut almost all violet/blue and red light

The modern GSO and other astro-specific yellow filters are either too weak (#8 cuts off around 440nm) or too strong (#12 cuts off around 500nm) to be useful as minus violet filters.  The modern #11 Yellow-Green filters pass too much red to be useful.  They're basically the same as a Hoya X0 Yellow-Green.

10 hours ago, Franklin said:

An active night vision eyepiece, something like a Quark that just plugs into a regular scope but allows you to see in NV.

The Collins Electro Optics I3 was pretty much that.  It didn't sell well, so it was discontinued years ago.

There are plenty of ad hoc NV astro solutions out there today, but I'm not aware of any as plug and play as the CEO I3 was.

2 hours ago, John said:

Is the availability of high spec NV sensors still impacted by technology export restrictions, primarily in the USA, or have things moved on from there now ?

 

So what's keeping the 40+ countries in Europe from designing and selling their own high spec NV sensors?

To raise up a Dob, lots of folks on SGL use a water butt stand:

I've found Dobsonian mounts very forgiving of slight slope because the center of gravity is directly over the azimuth rotational axis.  Alt-az mounts are not at all forgiving of slight slope unless you're using a counterweight on the other side because the center of gravity is way off to one side of the azimuth rotational axis.  This necessitates re-leveling the mount in the dark anytime you need to pick it up and move it to another location to dodge observing obstacles like buildings or foliage unless your entire observing area has the same slope and you keep your tripod oriented exactly the same from place to place.

For Newtonians with focal lengths of one meter or longer, I generally recommend the Dobsonian mount over the alt-az mount in my experience.  For shorter, just the opposite.

4 hours ago, johnturley said:

It actually states 50 degrees on the barrel.

Simply a case of saying it's so doesn't necessarily make it so.

My Baader Scopos Extreme 35mm says 70 degrees on the barrel, but it actually has a measured 66 degree AFOV and a 68 degree eAFOV.

9 hours ago, johnturley said:

Although it states 50 degree APFOV on the Vixen SLV, I find it to be nearer to 45 degrees.

The original Vixen LVs from 7mm on down were all 45 degrees.  I can't remember if they changed the claim to 50 degrees with the NLV or SLV line, but the actual optical design didn't seem to actually change, just the claims.

Well, I finally found an affordable, high quality cyan BG39 (minus red) glass filter.  It's a 1" (25.4mm) diameter bare disk, so I mounted it in a spare Meade UV/IR blocking filter mount with a just less than 1" clear aperture due to the retaining ring.  I had to leave the original UV/IR glass in place to keep it from falling out the front.  It's specified bandpass from the manufacturer (Newport) is below:

At best, it has an 80% transmission at 500nm (teal or blue-green).

Here's how it looks by itself and in combination with other filters through the spectrograph:

As you can see, it does a fine job of completely blocking orange-red and red light starting right around 600nm as specified.

I tried it out by itself and in combination with various other filters and in comparison to various other filters on Venus last night in my ST80:

• By itself, the Cyan BG39 filter transmits quite a bit of violet, but it does an excellent job of blocking red.  I saw simply a violet fringed blue-green disk with no orange or red flaring.  I'd say it was sharper than with any Yellow filter thanks to that.
• The best combination was with the Yellow K2 (#8) filter.  All violet and blue fringing was blocked along with the orange-red flaring leaving a nice and sharp disk.  The color cast was a pale blue-green.
• Next best was with the Hirsch Yellow #12A filter which left barely perceptible violet-blue fringing.  The color cast was a a very slightly more blue blue-green disk than with the Yellow K2 filter.
• The combination with the Hirsch Light Green #11 yielded a slightly darker image than with either yellow filter above.  It still had lots of violet-blue fringing, but no red-orange flaring.  The combination color cast tended toward blue-green while the Green #11 by itself tends toward yellow-green.
• The Yellow #12 combination was rather dark in comparison and overly yellow-green.  I wasn't a fan of it despite it blocking practically all poorly focused blue and red.  I would rather use the Meade Green interference filter to achieve that goal.
• In comparison, the Rokunar Green X1 (#11) yielded almost identical results to the Yellow K2 or Yellow #12A, just with a yellow-green instead of a blue-green color cast.  The best performing BG39/Yellow combinations both have sharper cutoffs and slightly higher combined transmission especially in teal/blue-green, but on Venus, it made little to no difference.  I preferred the Green X1 simply for the simplicity of a single layer filter.
• The Hirsch Light Green #11 by itself simply does too little to block either violet or red to be of much use.
• The various yellow filters do a good job of blocking violet, but the resultant orange-red flaring is probably just as bad as the violet fringing.  The violet fringing is well away from the disk while the orange-red appears as flares practically on top of the disk.  It's easy to ignore the violet corona, but it is impossible to ignore the orange-red flares distorting the disk image.

To try to break the Green X1 vs. Cyan-Yellow K2/12A tie, I tried the Green X1 and Cyan/Yellow combinations on the Orion nebula and the Trapezium.  Alas, I couldn't tell a difference on such dim objects.  No filtering was best by far for them.  I simply couldn't see any fringing on them without filters, so why use them?

On Sirius, I didn't find the color fringing all that objectionable.  I tried the various filter combinations, but still preferred the unfiltered view.

I've come to the conclusion that the poorly focused red and blue/violet light of fast achromats is really only a problem for bright solar system objects.  Unfortunately, that's what most beginners first point these scopes at and are less than impressed by the resultant views.  I'm sure at higher powers, it would also affect the ability to resolve globular clusters and close double stars, but most folks don't ever use these scopes for those purposes.

I'm more convinced than ever that a high quality 470nm to 610nm (or 480nm to 600nm if the cutoffs can be very sharp) bandpass interference filter of high transmission would be ideal to market as a planetary filter companion for fast achromats.  Now, we just have to convince some retailer to come to market with one.

If you have a Green #56 or Yellow-Green #11 filter on hand, try repeating the comparison on the moon with a filter in place on the ST80.  I've found a light green filter will greatly suppress the violet and red-orange flaring going on in the fast achromat on bright objects.  This then vastly improves sharpness by removing most of the veil of unfocused light splashed across the field of view.  Sure, you're left with a greenish view, but it's a much sharper view.

Try Venus next time.  It really sharpens up nicely with a green(ish) filter in the ST80.  It goes from a flaring blob of violet/orange-red light to a (mostly) sharp edged greenish disk in my ST80.

Is there a particular circumstance forcing you to use a diagonal in your imaging train?

10 minutes ago, Zermelo said:

Is that the eyepiece equivalent of "borderline personality disorder" in a person?

Hey, let's keep my personal life out of this. 😉

I bought a display Meade 8x42 binocular 25 years ago for a good discount.  It came with neither neck strap (I added a neoprene one) nor case.  I've kept it in a $10, soft sided, padded lunch cooler all these years.  It can sit out in its case, and no one thinks it's worth stealing.  The case is a little too big, but it squashes down for storage.  Something like this might work for your bins.

Plus, if an eyepiece has borderline kidney beaning (SAEP), a Barlow can exacerbate it, possibly making it unbearable.  A telecentric won't have any such effect.