Louis D

On 27/07/2022 at 07:13, Chandra said:

Of course, the ones you show in your photos go much further, but they are configurations designed for imaging, which need a plus stability.

I like CCD-Freak's overmounting example below:

That's an AT60ED up top.

32 minutes ago, Chandra said:

the stuffing costs much more than the chicken as we say around here.

OMG, that's a hilarious saying.  I've never heard it here in the states.

3 hours ago, Cosmic Geoff said:

I very rarely use my telescopes in a visual wide field role.

Because a lot of big, heavy eyepieces are 2" only as I pointed out above.  For instance, all of the ES-100 and ES-92 eyepieces are 2" only.

Vernonscope Brandons are 100% American made from glass melt to figuring to barrel to assembly.  These are the only consumer-grade eyepieces the US military are allowed to procure.

All Tele Vue eyepieces are US designed and are made in either Japan or Taiwan with no Chinese made content.

All Pentax eyepieces are assembled in the Philippines, most likely from Japanese glass.  Pre-Ricoh buyout ones are 100% Japanese made.

All Nikon astro eyepieces are made in Japan (I think).

All Takahashi eyepieces are made in Japan (almost certain on this).

Noblex are made in Europe (might still be Germany, they're going through a rough patch right now).

All GSO eyepieces are made in Taiwan, although it's not clear if they have Chinese made components.  They tend to be sold under various brand names as well.

Long Perng eyepieces are also made in Taiwan (I believe, and again with possible Chinese components) and sold under various brand names worldwide.

APM labels their eyepieces as Germany, but they are made in China.

Baader is a German company, but their manufacturing is in China.

A lot of vintage (pre-2000) Orion USA, University Optics, Vixen, Meade and Celestron eyepieces were made in Japan or Taiwan.  They will be marked as such on the chrome or black barrel or have a circled letter maker's mark (definitely Japanese then).  Sometimes, only the original box mentions the country of origin on lower end eyepieces.

Many premium spotting scope and microscope eyepieces (both new and vintage) that can be adapted to astro use are (were) made in Europe or Japan (Leica, Zeiss, Swarovski, Meopta, Nikon, Olympus, etc.).  Ask here or on Cloudy Nights for confirmation on specific models.

Truly vintage American Optical and Bausch & Lomb microscope eyepieces are 100% American made but will require adapters for astro usage.

I'm sure I missed a company or two in there, but this list will at least get you started.

Unless you're strictly using the TV APO straight through, you already have a 2" diagonal, so I don't understand the comment about buying a 2" diagonal.  They don't have to be expensive, though, if you want to keep one with the SCT.  I picked up 3 used GSO 2" 99% dielectric diagonals from Cloudy Nights classifieds to keep with various scopes for about $70 each.

You will need a 2" visual back if the SCT doesn't come with one.  They're about $25 to $35.

I would try the 2" eyepieces because there are some fine 2"ers at shorter focal lengths as well the longer widest field ones.  The 12mm and 17mm ES-92s are two I can think of right off the bat.  The 21mm Ethos also comes to mind.

$80 isn't too bad of a price, but you'd need to check out the mechanics of everything.  I'd also check the optics; but barring physical damage or fungus, they're probably okay.

In general, though, I've found sellers of entry-level scopes tend to overprice their scopes and accessories.  Given the slim market for used entry-level scopes (who wants to give their kid a used scope on Christmas morning?), they stay on the message boards for months.

On the other hand, higher end scopes and accessories are usually great to purchase used.  They are generally built to last in the first place.  Their owners generally take astronomy seriously and thus take good care of their equipment.

Less than 25% of my equipment was bought new.  Many advanced amateurs have much deeper pockets than mine and are always on the upgrade treadmill to my wallet's advantage.

16 hours ago, Chandra said:

I admit an AR150 is a sweet treat, but I certainly think it's a very heavy, high-torque beast that's hard to control with any mount on the market today.

I think you're overstating that a bit.  I would think any of the higher end EQ mounts would have no problem at all with it.  However, who wants to drop $5000 to $20000 on a mount for a $700 telescope?

That's an AP Starfire 160 on an AP1200 mount above, so I would think it would handle a Bresser Messier 152/1200 just fine.

Software Bisque also makes some good mounts that should have no issues with the 152, either:

2 hours ago, Mandy D said:

Because a Newtonian reflector has two mirrors, there can be no lateral inversion of the image at the focusser. However, because of the location of the focusser, there is an apparent rotation of the image. With the focusser in the normal location, this rotation will be 45 deg to the axis of the tube. An eyepiece will normally rotate the image by a further 180 deg, whereas a camera at prime focus will not. For imaging it is normal to rotate the camera through 45 deg anti-clockwise wrt the main axis of the tube.

Good point.  If you take out the eyepiece and look at the image of the moon directly down the focuser tube by pulling your head back a bit, does it look upright and non-inverted?  I'll have to check next time I'm out with mine.

1 hour ago, DaveL59 said:

Having been burgled twice

Despite living in a relatively higher crime area (not awful, just not super low), home break-ins seem rather rare.  Cars, yes; sheds, yes; homes, no.  I sometimes wonder if its because burglars know that about 30% of the homeowners/renters are armed to the teeth and are not afraid to shoot first and ask questions later since our Castle Doctrine totally backs them up on home break-ins.

2 hours ago, badhex said:

with this size of scope you can go from 4° TFOV at one end to 200x at the other merely with the switch of an eyepiece

Another advantage of short, fast fracs over long slow versions.  Of course, cost skyrockets to make them as color free.

4 hours ago, Zeta Reticulan said:

It's far better balanced than my Altair 60 EDF. I considered the 72mm version of the Altair, but there's a lot of weight in the focuser. My guess is all of these little scopes are aimed more at AP, with visual as a secondary market.  Consequently they are probably expected to be used on heavier mounts than purely visual astronomers would be likely to use. I also now only use 1.25" accessories and a short dovetail on the 60 EDF.  

Edited 4 hours ago by Zeta Reticulan

On my Astro-Tech 72ED, I have an 8" long dovetail mounted the opposite direction so I can balance heavy 2" eyepieces and 2" diagonal.  Then the problem becomes that the focuser tube slips out no matter how much tension I put on the focuser pinion.

Even on my TS-Optics 90mm Triplet APO, the load can make the R&P focuser unwind!  I have to keep a finger lightly on a focuser wheel to prevent it from happening.  Who designs a focuser that allows that to happen?  There are ways to design helical R&Ps to prevent this.

On 22/07/2022 at 17:05, Franklin said:

The Altair Ascent and TS 102ED f/11 are amazing scopes, quite long and need a beefy mount but the definition they give is superb and all with 51 glass. For around £750 new it's a great buy and they come with a split tube, so bino friendly and a dual speed focuser. What's not to like?

I guess it depends if you already have a beefy mount.  If you need to spend an additional $800 or more on a beefier mount, then you could apply that toward a shorter FPL-53 doublet or triplet of the same aperture.

I save homeowners insurance claims mostly for storm or water damage from sewer backups (dang neighbor tree roots).  These claims often exceed $5000 each.

If they're in stock in the fall time frame, I may ask Santa to bring me one for Christmas.  I would have to stay off the naughty list for the rest of the year, though. 😇

4 minutes ago, Space Hopper said:

Size comparison with an APM ultra flat 15mm, Docter 12.5mm, APM Superzoom in the middle, Tv 2" Powermate 2x, Panoptic 35mm.

Pretty substantially sized, isn't it?

Thanks for the early report.

2 minutes ago, Space Hopper said:

I had to drag the rig inside at this point as it decided to rain on me ! (Normal UK conditions !!)

Better than more 100+ F days.  We're still waiting for our first July rainstorm.  We also haven't been below 98 F all month.

2 hours ago, Zeta Reticulan said:

I'm just not that sure I can deal with a mirror-reversed Moon lol.

Don't ever get a Newt/Dob, then.  You'll have to lean over the scope from the side opposite the focuser to right the image (180 degree rotation).  It's not very comfortable and finders tend to get in the way.

Since I started on a Dob, I guess I just never let the whole image rotation issue bother me.  The left/right flip of a mirror diagonal makes using printed star charts more difficult than a 180 rotation.  For Newts/Dobs, you just rotate the chart 180 degrees.  For the image flip case, you need to try to look through the page from behind.  I suppose with electronic charts today, you just specify the preferred orientation to the software.

I guess mine's defective.  I took it apart after noticing it wasn't all that great, cleaned it up, and tried all four orientations of the two lens groups, but even in the best orientation (the original), it's still not all that great.

9 hours ago, Mr Spock said:

Small and very light. No weight - no frills. Great optics too 

If only I didn't have such strong astigmatism in my observing eye.  I do have a Circle-T Edscorp 25mm which I can use with eyeglasses, but it's not very sharp outside the central area at f/6.  I suppose if I had a tracking mount it might be useful.  Are the shorter focal length Abbe orthos sharper across the field at f/6?

22 hours ago, Zeta Reticulan said:

I've always wondered about decloaking my 19mm Luminos. It's basically a paperweight at the moment.

Peel off or puncture the Celestron logo and you can then access the small screw that the eye guard rides up and down on.  Unscrew it all the way with a jeweler's screwdriver, lift off the outer carapace, clean off the grease left on the main eyepiece casing, and store the screw and carapace together in case you ever want to put it back on.  BTW, the lens cap won't fit anymore.

6 hours ago, badhex said:

Haha whoops, operative part of a diagonal being that it changes the image path diagonally, and this items obviously does not. Clearly I was not thinking 'straight'.

I believe you are correct, it does look like it has prisms in there. Still, not much use for a newt so I'll set up a post to give it away.

And it wouldn't likely come to focus anyway.  The optical path through those is pretty long.

On 12/07/2022 at 10:38, Space Hopper said:

Finally an email from UPS to tell me my long awaited zoom is on its way, to be delivered by Friday.

I'm used to long waits for scopes and mounts, but not eyepieces till now. Lets hope its worth the wait.

 

@johninderby you've contributed to this thread quite a bit, and shown some interest. As you are local, if you'd like 

to borrow it and try it out, and put it through it paces, you'd be welcome. Drop me a PM sometime 🙂

Have you gotten it yet?

I just realized from reading the various CN reports on it that the presence of AMD or barrel distortion may be squeezing extra TFOV into the AFOV, enough that maybe it shows roughly the same TFOV at a given focal length as an eyepiece with a 75 degree AFOV that has strong pincushion distortion.  If it's eAFOV is greater than the 67 degree AFOV everyone seems to be seeing, this might explain the original 75 degree claim from the designers.

The 26mm Meade MWA (really a 25mm eyepiece) has an 83 to 84 degree AFOV and a 90 degree eAFOV, which is the same as the 25mm ES-100 which has a 100 degree AFOV.  Thus, the designers claim a 100 degree field of view since it sees the same TFOV as a competitor's 25mm 100 degree AFOV eyepiece.  Convoluted yes, but I can see their reasoning.  The Meade just gets there with barrel distortion instead of the ES's pincushion distortion.

I guess we need someone to measure the APM SZ's TFOV at a few focal lengths to back into the field stop diameter after taking the scope's focal length into account.

6 hours ago, badhex said:

rather rustic diagonal

I don't see a diagonal in your photo, but I do see an inline image erecting assembly.  I believe it uses Porro prisms like a binocular, so no spike on bright stars like an Amici erecting prism diagonal.

I can always tell when I have the camera at the right spot for my AFOV images because the field stop pops into view and going any further inward produces blackouts.  Of course, if there's massive SAEP/CAEP in the eyepiece, or if there is no distinct field stop, this complicates matters for me taking my images.  I then have to find the best distance that represents what the eye sees.

So most are very close to a pound.  That fits in nicely with Pentax XW and Delos weights.