Louis D

I guess I'll have to give it a bit more effort now that I know it should go downward. I've pulled the rubber eye cup off before. I'll have to try using a lens spanner/wrench to undo that top ring to see if the whole assembly drops off downward. I'm trying to make these things eyeglass friendly for me and my daughter. The both of us have a lot of eye astigmatism. I much prefer the Meade HD-60 line for this reason. There's basically no eye lens recession once you flip down the rubber eye cup and fully twist down the extendable eye guard. She's got both sets at her house right now, so uncloaking experimentation will have to wait.

I can unscrew the printed ring and then the colored beauty ring slips off, but the big upper part won't unscrew or slip either direction. However, I was trying to get rid of the eye cup because it eats up 4mm of eye relief, causing the eyepiece to go from 16mm to 12m of ER, making it appear more like a Plossl with eyeglasses. It appears the eye cup is still solidly attached when done with your decloaking. Thanks for the clear photos and explanation, though.

My daughter's 127 Mak is somewhere in the middle. It's stored in a Walmart duffle bag wrapped in bubble wrap.

In the OP's defense, where in the included instructions did it mention this crucial adjustment as an important check, and how to perform it if it is such a common occurrence? As a practicing engineer of many years myself, this episode would cause our group to perform a root cause failure analysis, call for suggestions to correct it, come to a consensus on the best way forward, and then put an action plan in place to prevent recurrence.

Yep, here's the link.

Tips from Texas for solar observing in extreme heat: Wear a wide brimmed, ventilated hiking hat to avoid sunburn on the head while avoiding cooking your brain. Put a large box fan blowing on high across your body at 90 degrees to the direction of the scope. Wear shorts and a T-shirt or very light fabric, full covering clothes that breathe well. I can manage about 20 to 30 minutes at noon solar observing in 95+ F heat before I need a break in the A/C to get water, cool off, and to avoid sunburning my arms and legs. If you don't have A/C, I recommend placing cold/damp washcloths on your head to cool off your brain to avoid heatstroke. You can keep them on your head under your hat when you go back out, at least until they warm up to ambient temperature, then remove them because they then impede evaporative cooling. Cool/damp cloths around your neck can also help as well. The key thing is to listen to your body. If you start feeling woozy or lightheaded, start cooling off immediately. Your brain does not like overheating and needs to be cooled immediately to avoid passing out. It generally shuts down first in my experience. Laying flat on the floor can ease the strain on your heart and allow blood to flow through your brain more easily to cool it. If you can't get inside for whatever reason, find shade ASAP, lay down, and call for help if someone is in earshot.

This is where I got stuck by that middle section not unscrewing up or down. Perhaps mine is theadlocked.

I just wrap my OTA in an old, thick blanket in the trunk (boot) during transport. Seems to work fine for me.

I tried with my AT Paradigms (BST Starguiders), but I couldn't get the upper metal assembly to come off. Is the trick using a lens spanner/wrench to remove the upper ring of the twist-up eye cup?

I just have to ask why the focuser tension wasn't adjusted properly at the factory. Have they simply given up on imparting a good customer experience out of the box?

An f/12 scope is very forgiving on eyepieces. Even cheaper, simpler eyepieces can be decent at the edge in it. A Barlow could be useful to up the power while maintaining long eye relief with longer focal length eyepieces so you can wear your eyeglasses at higher powers. On the other hand, the exit pupil gets small rather quickly at f/12, so eyeglasses might not be needed for astigmatism correction.

Did you mean 10mm eyepiece? If so, I would wholeheartedly agree.

Worst case if this doesn't work out and replacement parts aren't available from SW, try putting an off-axis aperture mask on the other side (or wherever the remaining optics are best) and you'll have an unobstructed system. Sure, it will be heavy and bulky for the aperture, but still usable.

I've been using Baader solar film in a homemade cell since it came out over 20 years ago. It's an incredibly tough film. A forward-back shake while viewing the sun or an incandescent filament will reveal any damage if you move the sun/filament around the entire aperture. Tears would be immediately apparent from the shake as air would flow through the gap. The bigger concern for me would be the filter falling off due to a poorly made cell. Mine is a very snug, custom fit and doesn't come off without coaxing. My Hercules 1.25" wedge looks nearly identical to the Lunt above except that the white ceramic heat sink is visible like the Altair wedge. When used with my 90mm APO under the Texas sun, the white disk doesn't get any hotter than mildly warm. I can keep my thumb on it with no discomfort. If you're concerned about that residual 5% light going up to the eyepiece or camera, don't be. It gets further attenuated by a 1:1000 neutral density filter (ND3) below the eyepiece holder. There just isn't much heat energy left at that point. It's still too bright for your eyes, so you'll need a variable neutral density filter or similar on the eyepiece. Some wedges have this functionality built in. My bigger concern is the focused sun's energy striking the interior side wall of my focuser over time if I walk away from my scope on my non-tracking alt-az mount. I'm concerned it will scorch the interior blacking paint/material. As such, I always cap the front of the scope when walking away for any reason. I have enough experience as a child with a 2" magnifying glass to know that it doesn't take much to ignite combustibles with the focused energy of the sun. BTW, 1.25" wedges are generally only rated up to 125mm scopes. For 150mm scopes, a 2" wedge is recommended due to the larger heat dissipation capacity. If the prism wedge itself got scratched, although I don't know how that would happen because it's hard to get to, you would have some loss of image contrast due to scattered light. Let's say the scratch does somehow lead to prism failure and it shatters. That's the beauty of the design right there. 100% of the light dumps out the back instead of the normal 95%, and none of it goes up to the camera or eyepiece. The failure mode leads to a safe condition.

I have such long eye lashes that I end up touching the top of the eyepiece, and perhaps the eye lens itself, with short eye relief (12mm and less) eyepieces. I find this very disconcerting and uncomfortable. It can also leave eyelash gunk on the eye lens. Normally I wear eyeglasses at the eyepiece due to strong astigmatism, but sometimes I'll check what tighter eye relief eyepiece FOVs look like without them to see if it is possible to take in the entire view comfortably. This is less of an issue with volcano tops. It's the flat tops that are bad. Sometimes I can't even get in close enough due to the diameter of the eyepiece top exceeding the inner diameter of my eye socket (e.g., the 20mm Meade 5000 UWA).

That should work. I get much improved performance from my microscope and Svbony eyepieces in my binoviewer when Barlowed by about 3x to f/18 or so in my scopes. The rays will be strongly diverging, so there could be exit pupil issues because eyepieces are generally designed for converging light cones.

That's SkEye Cam, which appears to be for astrophotography with a cell phone camera. I'm not sure how the plate solving plays into it. Regular SkEye planetarium app makes no mention of plate solving.

The whole point of plate solving is to do an end run around the phone's inaccurate sensors. Otherwise, you've basically got SkEye's system of locating pointing direction using only sensors. They just need to add offsets to the values provided via plate solving to account for inaccurate phone to scope alignment. That's basically what SkEye does. It doesn't know how well aligned the phone and scope are since there is no initial alignment step. You center the scope's FOV on a known star, locate that star on the app's star map, and then tell it to align on it. Bam, the app knows the offset between the phone and scope. Do this a few more times as you locate more objects, and the alignment offsets get further refined. If SkEye added plate solving, possibly using the front camera to do an end run around Celestron's patents, it could really improve pointing accuracy. As long as the camera can see some portion of the sky, even at right angles to the scope's line of sight, and it knows the alignment between the phone and scope (it might require two alignments, one for the sensors and one for the camera), the app can calculate where the scope is pointing. That would negate the need for the Starsense mirror. If the phone is tilted up from the scope too much to make it easier to see at low elevations, the camera wouldn't be able to see the sky at high elevation aimings. That's the main issue I foresee with this approach. Another issue would be obstructions above and behind the scope as in my backyard. I've got trees preventing views north of zenith. Thus, when looking south, a phone flat on the scope's tube is looking up and back at a bunch of tree limbs to the north.

Yes. Notice how the red and blue patterns in the diagram don't overlap very well for the Huygens design. You would see CA even on axis.

I've noticed there are some folks who think the original 30mm and 40mm XWs are preferable to the new XW-R versions and will pay a premium for them.

@vlebo Please take a picture of where the Pentax XW 30mm has an S in its designation. Perhaps you have a misprint, and thus a collectible.

Either it's a scaled down version of a longer focal length 82 degree eyepiece (think 16mm NT5 vs 31mm NT5), and thus everything but the AFOV gets smaller, ER included; or it's a different design achieving the same AFOV, but with a smaller ER. As Don says above, a smaller eye lens at constant AFOV leads to less ER. Why didn't ES choose to maintain constant ER and AFOV throughout the 82 range? Only they would know. I'm guessing it was to keep the line more compact and affordable. Look at how big the ES-92 line is with constant 92 degree AFOV and 17mm usable ER.

Be aware that the 16mm NT5 has very tight eye relief. Otherwise, it's a highly regarded gem of an eyepiece, but at a price. The higher power will make the sky background darker, allowing most objects to stand out better.

If it's the middle one, it looks just like the image below, minus the eye cup:

I would get the GSO 1.25" 90-deg 99% Dielectric Mirror Diagonal based on my experience with the GSO 2" 99% diagonals. I'm not a fan of my William Optics 1.25" 99% Dielectric Dura Bright Carbon Fiber Star Mirror Diagonal. It has a 22mm restriction at the bottom of the eyepiece receiver which vignettes widest field eyepieces.