Louis D

I have the 127 Mak as well, and the 72ED is way more of a G&G scope thanks to its wide field of view, lighter weight, and more compact size.  I'm not sure the 127 Mak would be much of an improvement over the 102ED that the OP wants to replace, other than being shorter.  The 90 or 102 Maks might work for the OP based on weight and size, though.

2 hours ago, vagk said:

But isn't this ring necessary to keep the eyepiece barrel from hitting the mirror?

It need not be any thicker than the eyepiece barrel thickness which is at most 1mm.  Kept at that width/thickness, it would not contribute to vignetting.  The SW/WO diagonals go with at least a 3mm lip, which is completely unnecessary.  I have a 1.25" WO diagonal with just as thick a lip, and the vignetting in a 32mm Plossl is quite noticeable.

Good report.  A little disappointed to hear that even with a Dioptrx you can't see the entire FOV.  BTW, did KUO ever send your test Dioptrx back to you?

I'm surprised you needed only 8mm of additional in-focus in 1.25" mode.  Looking at the diagram below, I figured it to be much more than that.

The diagram showed it would be closer to 32mm inward from the 1.25" shoulder, or 24mm inward of the 2" focus position.  Did the housing get significantly changed or did the focus point end up somewhere between the 1.25" and 2" shoulders instead of 8mm above the 2" shoulder?

I've had an Astro-Tech 72ED for quite a few years now.  It's a great grab and go scope.  Even though it will accept 2" eyepieces, I've had trouble with heavier ones causing the focuser tube to slip as you approach zenith.  I've tried increasing the loading tension, but it still slips.  I'd recommend an R&P focuser if possible.

I've read that the SW 72ED focuser has rather limited travel and can cause problems when using a 2" diagonal.  The AT 72ED (from Long-Perng, I believe) doesn't have this issue with its long travel focuser.

Visually, it doesn't show false color except above 100x.  Even then, it's a mild violet that could be filtered with a weak yellow filter if it bothers you.  Both it and the SW have FPL-51 equivalent glass.

Overall, it's a fun scope for low to mid power viewing.  It can also be used up to about 125x without too many false color issues.

If you can stretch your budget, I'd probably get the TS-Optics Photoline 72mm Doublet APO or Astro-Tech AT72EDII FPL-53 if starting from scratch.  These would have better color correction, better R&P focuser, and better rail attachment.

Check to see if your SW diagonal has a restrictor ring at the bottom of the eyepiece holder tube.  If it does, I'd make sure any replacement does not have one.  I know the GSO made 2" dielectrics do not have this issue.

It's a Celestron Regal Zoom 8-24mm that has had the original eye cup screwed off and replaced with some aftermarket bits and pieces.  It was sold with Celestron Regal spotting scopes.  I've measured the actual focal lengths to be 8.2mm to 21.2mm.

It's step up from the standard Celestron 8-24mm zoom, but not quite as good as the Baader Hyperion Zoom.  The biggest issue for astro usage is that there are no filter threads.  The lower lens group goes right to the end of the barrel at one end of the zoom range.

Here's some photos of mine.  The upper two are from a 65mm spotting scope.  The bottom one was the version sold à la carte with markings for all three spotting scope sizes.  Yours must have been sold with a 100mm spotting scope.

7 hours ago, rwilkey said:

In f/5 and similar scopes the 32mm Panaview is soft at the edges but absolutely stunning on-axis.  It was the first upgrade I ever bought for my 200P and led me down the 82º route, just like Bingevader above.

Same with the 30mm 80 degree WideScan III clones.  It has horrible field curvature leaving the outer 50% blurry.  However, the central 50% is pin sharp.  It's noticeably sharper than the 30mm ES-82 in that area.  By over-correcting refractor field curvature, I discovered it actually has fairly low astigmatism in the outer 50%.  If it was sold with a field flattening group ahead of the field stop, it would be a real contender.

14 minutes ago, Mike Q said:

I wonder what the customs fees would be on that 

Zero.  Covered under the $800 personal de minimis exemption.  I can't help it if other countries don't reciprocate.

2 hours ago, Zermelo said:

On sale: https://www.firstlightoptics.com/baader-holiday-special-2022/baader-hyperion-zoom-eyepiece.html

though it was so popular it is now out of stock.

That makes it $110 cheaper than buying it in the US.  Add in the fact FLO doesn't charge state sales tax, and you save even more.

Blue/violet color fringing is classic achromat chromatic aberration.  Observing at higher powers will reveal it more clearly.

As for why the MA looks worse at night, stars are the absolute acid test of optics.  Any aberration anywhere in the field will be seen with stars.  Even aberrations in your observing eye will be seen.  Extended objects seen in the daytime are much more forgiving than stars because your brain is forgiving of blurred objects, but not of aberrated stars.

4 hours ago, AstroMuni said:

Take a look at this site too https://astrobiscuit.com/best-budget-telescope/

The venerable 60mm slow achromat was THE go-to Christmas gift telescope for decades.  Back in the day, the mounts supplied with them were a bit better than today's mounts (vintage scopes came with a cast iron head and hardwood legs).  The scope isn't the issue with a 60mm f/11 achro, it's the mount they come with nowadays.  They typically can't handle the long moment arm.  The fact that little kids have great difficulty hovering over an eyepiece and keeping their hands off the scope and mount when observing tends to doom these scopes today.  They go off target at the slightest touch and/or shake incessantly long when touched.  Focusing and nudge tracking become aggravating in a hurry.

On 02/11/2022 at 09:15, xpm said:

We live in a Bortle 7 location, but will look to do some dark sky camping with the scope once we have one. That being said, seeing things from the garden will also be a requirement.

Make sure to consider size, weight, and transportability for both camping and backyard use.

7 minutes ago, bingevader said:

There are a couple on https://www.astrobuysell.com/uk/.

Wow, someone is asking £70 for one which almost the new price when VAT is removed (£74).  Unless that person is collecting VAT, that is ridiculous.  In the US, we always price used equipment against the new, without tax, price.

Mostly for resolving globular clusters like M22 and M13 at 200x and above.  Much below that, and they just look like a fuzzy spot.

I haven't found a grill cover that lasts more than a season or two under our hot Texas sun, hail, high winds, deluging rain, ice storms, etc.  I just bought a 100% heavy gauge stainless steel grill so I don't need to worry about covering it.  As such, I would never leave any astro equipment outdoors here under any soft cover all season long.  Perhaps at a star party during the day, but that's it.

Basically, it would have about the same field correction.

If you're clever, you can make your own version of the AstroStuff RQFS.  It's just a Synta/Vixen finder foot (check ebay), a riser of some sort (3D printer or carved wood or plastic or even machined aluminum), a 1.5" or so small bolt with nut, and an original Rigel QuikFinder shoe.  I bought one from AS, but they're local to Texas, so not that expensive.

1 hour ago, Carbon Brush said:

Those that comprise a heating element inside a pyrex tube with bung will get very hot if not cooled by 50L of water🤣
I speak having run one in mid air and it melted the cable when it came into contact with the glass.

OMG! 😲

1 hour ago, Carbon Brush said:

Mains voltage filament lamps are all but obsolete devices in the UK and Europe. We use LED almost everywhere.
OK small lamps for cooker hoods or inside ovens or other specialist applications can be bought. But the genral 60W/100W bulbs are gone.

I bought a few dozen over a decade ago in various sizes when the big compact fluorescent push came out.  I couldn't stand CFs or fit them in some of my fixtures, so I wanted an alternative.  LED bulbs don't bother me and do fit in all of my fixtures, so I have a big supply of unused incandescent bulbs in the attic.

I was going to say that heating pads might be another option; although I've never read of anyone using one.  My mother used to put one under a bowl with bread dough and covered both with a dish towel to encourage the bread to rise, so it might work with a covered telescope if you can keep the heat trapped.

I just have to ask "Why?".

If you want equatorial tracking, put it on an equatorial platform.

Do you want to do DSO astrophotography with it?  I doubt if the struts are rigid enough for astrophotography.

You do realize how heavy an EQ6-R-Pro would be, right? (93 pounds)  Why would you want to haul all that extra weight out just to observe?

2 hours ago, Stu said:

I can’t even remember what they are called!

Spider vane apodizers.

On 30/10/2022 at 11:22, Ratlet said:

As it's a telephoto there's only about 45mm, maybe 50mm when I remove the m42 mount to play with.

Regular 1.25" right angle prisms have a 63mm to 67mm optical path length.  I would think an Amici prism might add a bit to that.  It certainly won't be any shorter.  You might be able to make a straight through finder, but I have my doubts about a RACI finder.

1 hour ago, starhiker said:

 

This combination with Skeye is inspiring. Thanks. What is the name for the phone holder?

 

Home brewed special:

My refractor night-time finder setups:

RACI/GLP/QuikFinder

RACI/SkEye/QuikFinder

On my Dob, the Telrad sits on its own base due to its sheer size/bulk.

You can pick up a Neodymium filter for cheap these days as one of the cheap moon & skyglow filters out there on ebay or other sites.  They are basically the same as the more expensive ones, but with a tad less transmission.  That way, you could see for yourself if they enhance any objects.

You would just need to make sure you're getting a low profile one.  I just noticed a bunch of them are high profile now that won't fit in your filter wheel: