Louis D

12 hours ago, AlexK said:

The above double-sided one is a way better design compared to the classic one. First of, it has much less distortions. Clean to comprehend, and even has lines teaching you the bright constellations stars finding with pointing figures. E.g. Arcturus is on the extension of the UMa "handle".

Regarding planets not charted, Louis, you supposed to watch for the ecliptics line on that chart (dashed). Planets are bright stars. So if you follow the ecliptic line on the sky and stumble upon a bright star not charted on the planisphere, that's a planet (or an UFO). You can learn distinguishing outer planets by their color. While Venus and Mercury are day and night in brightness and always close to the Sun. Also, there is a common misconception that planets do not blink compared to stars, but that's referring way back into the days with no industrial pollution to speak about much.

Oh, I know all that now, but starting out 23 years ago, not so much.  I don't even have to look at constellations to know where the ecliptic is during the different seasons now.  I just have a feel for its path across the sky having followed so many solar system objects over the years.

I've been using a "The Night Sky" 20°-30°N Large Planisphere for over 20 years as needed.  You just line up the standard time with the date and either hold the south side over your head when facing south or the north side when facing north.  There is some distortion near the edge, but it's not horrible.  It's pretty accurate about what is up and shows the motions well during the night.  It's handy for quickly getting oriented when you haven't been out under the stars for a while and requires no batteries or boot time.  It is useless for planets, I'll say that. 🙄 They also make versions for 30-40°N, 40-50°N, 50-60°N, and a catch-all southern hemisphere version.

I lined mine up for 9pm standard time on May 10th and took these scans so you can see for yourself what it shows.  It would be nice if it included a few more brighter objects.

South:

North:

1 hour ago, Soligor Rob said:

So if it was between the 14mm or 12.5mm which should I buy? bearing in mind I intend to purchase the 17.5mm & 9mm when they become available.

Definitely the 12.5mm.  It will fit nicely between the other two whereas the 14mm will be too close to the 17.5mm.  That, and the 12.5mm is supposedly better corrected and flatter of field than the 14mm which I do have.  I can confirm minor amounts of field curvature and astigmatism/chromatism in the last 10% or so of the 14mm's field.

2 hours ago, JeremyS said:

“Quite good” is an expression that I’ve come unstuck with a couple of times with US colleagues. In British English it generally (but not universally) implies that something is passable, generally OK, not terrible. But not as good as I was expecting.  That’s how I use it. But I understand in US it (often) means really rather good, certainly better than OK but slightly less than superb 🤔

"Quite good" has the subtle addition of being surprisingly good or exceeding rather lowered expectations.  Your UK meaning would probably expressed as "okay" or "passable" or "good enough" in US English.  Should I say "Really rather good" to mean exceeds lowered expectations.  I didn't want to imply premium level quality when they're not, but that they significantly overachieve given their price.

On 09/05/2021 at 09:40, Soligor Rob said:

Right I've taken in that most here rate the Baader Morpheus EP's fairly high, so can I ask how the compare to the Celstron X-Cel LX range of EP's.

I haven't done back to back comparisons at night between my Meade HD60s (supposedly similar to the X-Cel LXs) with my two Morpheus, but the shorter focal length versions are quite good.  The Meade units have somewhat blurry field stops, slightly tighter eye relief, smaller AFOV, and possibly poorer stray light control than the Morpheus.  You can look at my eyepiece photographic image comparison thread to see how the HD60s compare to other eyepieces as well as my Morpheus eyepieces.

I've projected the full moon onto my palm with the eyepiece removed from my Dob.  It's certainly bright enough to be easily seen at night in a darkened location.  Of course, the image focuses quite close to the top of the focuser, so it would need projected onto a translucent material for easier viewing with a Newt.  Fracs might have enough back focus for front projection.

It should also be doable, though dimmer, with an eyepiece or Barlow in the focuser.  This would allow for the image to be larger and focused farther from the focuser.

Away from full moon, the image will be dimmer, but might still be doable.

This would definitely not work very well during a lunar eclipse.  The moon gets very dim during them.

5 hours ago, Peter Drew said:

The Moon can be projected but it will be very faint unless it's close to the eyepiece and low power.  The Sun is unbelievably brighter than the full Moon, mag-26 compared to mag -12, mentally compare this to the difference between a mag +12 star and one of mag +26 star.  We project the Moon on a 72" monitor by using a DSLR connected to the telescope and the monitor for outreach.        🙂 

Keep in mind how much lower the ambient illumination is at a dark site (that is not too close to or above the Arctic Circle) compared to the daytime.  This helps immensely with viewing the projected ~40000x times dimmer moon.

Those Parks and Fullerscopes scopes/mounts look like they could be cousins.

I tend to use a pair of zooms in my binoviewers because changing two eyepieces and making sure neither is tipped is a real pain compared to twisting the zoom collars.

There are a bunch of different Telrad dew shields.  I have this one, but rarely use it because dewing hasn't been much of an issue for me.

2 hours ago, fozzybear said:

thats not possible she has a room full of them believe me

 

Amazon seems to have a room sized box.

7 minutes ago, ollypenrice said:

Hang on, people are saying that they are using the same ones after over twenty years. What can be wrong with the build quality?

They are quite big, yes, but they use proper batteries, not those festering little watch batteries which you can't just buy in 

Yes, easily available and easily corrodible batteries.  Perhaps this isn't an issue in SE France, but it's a big issue in central Texas.  I also had an expensive camera flash and a vintage Viewmaster viewer die this way.  No amount of cleaning contacts will help.

Do you remove the batteries from your Telrad after each use?  I do this with my flashes, laser collimator and other infrequently used, disposable battery operated devices now.

1 hour ago, fozzybear said:

My telrad is at least 17 years old with the Alloy battery holder  still have the original cardboard box with foam 

Still on the original AA batteries?

1 hour ago, Stu said:

You haven’t met Louis have you?

What a great likeness. 😁

As far as exit pupil goes and wasting light, who cares?  I can use the 40mm on my 127 Mak as well to keep down the exit pupil.

When viewing large, bright open clusters in an f/6 Dob, getting the whole thing into a single view is more important to me than worrying about a few photons crashing into my iris instead of my retina.  When I was showing my daughters and their boyfriends the Pleiades and Collinder 70 over Christmas through my 40mm SWAs (Meade 5000 SWA and Pentax XW in two different ~f/6 scopes), none of them said "Oh my God, stop wasting photons with too large an exit pupil!  Replace those eyepieces with your 30mm ES-82 and APM UFF eyepieces immediately".  They just reveled in the sight of those magnificent clusters.

1 hour ago, Don Pensack said:

SAEP is more of a problem when the eyepiece has a large exit pupil and less of a problem with a smaller exit pupil, though I don't think there is a hard cutoff on that scale.

I wonder, but have never read anything about it, whether spherical correction (myopia or hyperopia) in the eye can influence one's sensitivity to it.

 

It tends to be an issue until fully dark adapted so your iris can take in the entire exit pupil.

I know presbyopia has little to nothing to do with it because eyepieces with SAEP looked the same to me before I got it and after.

What I'm trying to figure out is why SAEP is more noticeable in slower f-ratio scopes.  Perhaps something to do with the combined exit pupil size between the scope and the eye?

About 8mm in my experience.  That yields a 0.6mm exit pupil (assuming an actual 118mm aperture) which is right at my limit with floaters. YMMV

2 hours ago, ollypenrice said:

Update: this post is ten years old. Telrads still going strong.

Olly

Keep a close watch on your batteries.  Once mine corroded inside the Telrad after 12 years, I couldn't get it working again even with a new battery holder soldered in.  No such problems with the 20 year old lithium button cell in the Rigel QuikFinder.

1 hour ago, Don Pensack said:

And a 50x/100x/150x/200x/250x sequence is exit pupils of 4mm, 2mm, 1.3mm, 1.0mm, 0.8mm

And I'll once again advocate for widest field at about 30x and exit pupil of 6.7mm with something like a 40mm SWA.  It's a noticeable jump up in true field of view when trying to frame large clusters like the Pleiades or Collinder 70, that is unless you're using a 25mm ES-100 to get a 4.2mm exit pupil, in which case the difference is only 0.25 degrees, so not a big improvement then.

On the other hand, a 6.7mm exit pupil is not very useful for hunting faint fuzzies due to the washed out background, but it's hardly noticeable when taking in bright clusters.  That TFOV is also handy for centering bright objects when your finders aren't exactly aligned with the main scope.

We get up to softball sized hail (about 4 to 5 inches) on rare occasions in Texas and Oklahoma, though not around here.  They tend to fall closer to between the Oklahoma City and Dallas-Fort Worth latitudes.

2 hours ago, jetstream said:

go for the low scatter XW 7mm, get a 10mm Delos and thats about it. If a 3.5mm XW came wandering by I would grab it but it would be last on my list.

I have the 10mm Delos and love it.  Absolutely no flaws edge to edge even without a coma corrector at f/6 (yes, I've swapped repeatedly and found no difference).  By comparison, the 12mm ES-92 really needs a CC.

I also have the 9mm Morpheus, and it appears to be very close to Delos quality.

The 7mm XW shows a bit of chromatic aberration off axis on bright stars, so a bit of a disappointment for me.  Otherwise, it is quite sharp and contrasty.

My venerable 5.2mm XL is still an excellent performer at that focal length.  Sharp and contrasty edge to edge with no faults that I can detect.

The 3.5mm XW is very sharp and lacks any faults that I can see.  However, that is one tiny exit pupil it produces, so I rarely use it.  I tend to binoview at those exit pupils to keep floaters at bay.  I picked it up for $215 during an Amazon flash sale, otherwise I wouldn't own it.

All that said, I've thought about picking either or both 6mm and 8mm Delos eyepieces.  However, I rarely feel a need to split the difference between the 7mm and 9mm and 7mm and 5.2mm eyepieces.  I do have the 5-8mm Speers-Waler zoom if I really feel the need for those focal lengths.  However, it's eye relief is lacking for eyeglass wearers despite the LER of Waler meaning long eye relief.

I highly recommend the 30mm APM UFF.  It's basically flawless edge to edge with high sharpness and contrast.

What's your budget?  I recommend getting a deep Pelican style case so eyepieces can be stored upright.  That way, you can pack more eyepieces into the case.  The cheap, aluminum looking cases out there actually have thin walls made of textured and painted plastic that puncture easily if banged up against a sharp corner.  The blow molded Pelican style cases are practically indestructible by comparison, as well as being waterproof.

Something like this case on Amazon would be ideal for large eyepieces without breaking the bank.  I've found these Chinese made cases are very robust.  Certainly not quite as good as my Doskocil case, but a fraction of the cost.  Just make sure it is sent with the P&P foam inserts.  Apparently, one reviewer got one without any.  I'm guessing a resold customer return.  Apparently, the actual case is orange based on review images, hence the clearance price.

3 hours ago, Stu said:

Looks like this should be delivered tomorrow with any luck! Expect hailstorms and floods 🤣🤣

Do you guys actually get hailstorms like we do in Texas?  We never hear about it over here.

Our town just got pummeled three weeks ago by baseball sized hail.  Luckily, my house was on the edge of it and only got up to about 20mm hailstones that didn't do much damage other than strip a few leaves off trees.

Here's some images from folks who got it much worse than me.

I looked through one being run by a beginner at a star party a few years ago, and the image of Jupiter it was showing was much sharper than the views through other 8" SCTs on the field that night.  Apparently, the optical corrector in the rear baffle really helps bring out low contrast details.  The owner had paired it with Delos eyepieces and was running it with a tablet wirelessly.  It all seemed to work seamless together for him as he selected other objects from the tablet to slew to.  It made me think about getting one for fun.  Highly recommended if you've got the money.

2 hours ago, John said:

Sadly I believe they are no longer in production. They do have a wonderful reputation though

My mid-range is a 13mm Ethos and a 14mm Delos.

 

Sadly, nearly the whole company closed up shop.

2 hours ago, CraigT82 said:

Really? Better let these US scope makers know...

Teeter

Obsession

There's always one in the crowd who has to prove me wrong.  Hope you're proud of yourself. 👏 😒 😄

1 hour ago, CraigT82 said:

51 inches

Indeed.  Not even Americans use inches for focal length.  Aperture, yes, focal length, no.