Louis D

Kind of reminds me of how underwhelmed I was when I finally saw Mt. Rushmore for myself. I kind of expected it to be bigger and grander, but the heads are only 60 feet tall seen from 1000 feet away. In contrast, I was overwhelmed by the Iwo Jima monument when I finally saw it up close for myself. The figures are about 30 feet tall seen from about 35 feet away. I guess I need to get within 70 feet of Mt. Rushmore to get the best effect. 😄

Try combining a cheap Moon & Skyglow (Neodymium) filter with a #8 or #12 yellow filter (depending on how much violet and blue you want to cut) to create a poor man's Contrast Booster. You might have 10% to 20% less transmittance, but that hardly matters on Jupiter or Mars at opposition. Here's a solar spectrum comparison I worked up to show the effects: Compare to the official Baader spectra for several of their filters:

At f/8 and above, a spherical primary could be considered acceptable for non-planetary observing. No amount of collimation will improve an f/4 spherical all that much.

In my own 72->90 journey, I went from an FPL-51 f/6 doublet to an FPL-53 f/6.7 triplet and have had no regrets. That, and the mechanics of the 90mm were much better. The 2.5" R&P focuser and camera angle adjuster make for a much better experience. False color went from barely noticeable to nonexistent. You're right though, even with the FPL-53 triplet, out of focus stars show red/green on either side of best focus. The 90mm is quite a bit heavier than the 72mm as well; but it's nothing my DSV-2B mount can't handle. If you've already got a 72mm FPL-53 doublet, you're going to need to jump up quite a bit in aperture to see a significant improvement in resolution performance. Something like a 125mm FPL-53 doublet or even triplet might do the trick. Of course, you'll probably need a much beefier mount. Along these lines, I bought a 6" f/5 GSO Newtonian to see how it performs. So far, the jury is out. I think I much prefer my 8" Dob in every respect. Aside from astrophotography, I'm not sure what the advantage is to a Newt on an alt-az mount. Sure it's smaller to store, but not all that much, especially when you figure in the mount head and tripod. That, and it has a massive secondary to favor astrophotography which does nothing to improve visual contrast.

Quite similar to the visceral experience of attending a Broadway/West End play/musical in person versus watching a video of it on TV. There's simply no comparison at all. Maybe someday with advances in virtual reality the gap will be closed; but for now, live and in-person can't be beat.

No idea how powerful my cheap, direct from China, ebay laser sights are, but they're plenty bright to see from multiple feet away in clear skies when aiming my scope. I'm pretty sure they're not IR filtered, so I'm insanely careful using mine. I recommend getting the laser sights with the bigger, 18650 battery instead of the smaller, 16340 battery. I've had much better luck with them in all temperature conditions.

I've found little kids at outreach events get annoying trying to jump up and grab your laser pointer to play with like a light saber (parents need to reign in their kids, but don't), so I just don't bother with them anymore due to the risks involved. If it's just responsible adults (no inebriated folks present), then laser pointers are fine.

I was out observing the moon last night with my 8" Dob without coma corrector (to eliminate its SA), the 3-8mm Svbony zoom, and the 5-8mm Speer-Waler varifocal. Here are a couple of impressions from this session: The purple/yellow fringing was largely gone at 3mm and 4mm. Only a small bit of yellow fringing remained in both eyepieces. I must have been seeing violet chromatic issues introduced by the "APO" triplet at tiny exit pupils. Both were showing subtle mara contrast details quite well no matter where I put them in the eyepiece's AFOV. Both fields appeared flat of focus center to edge to my presbyopic eyes. 5mm seemed to be the limit of usable magnification last night. Any higher, and my floaters got in the way, and no more fine detail was revealed in the Svbony. Again, 8mm in both seemed best. The lack of a CC didn't seem to hurt axial details moved to the edge all that much with this extended object. What was more important was slanting my view with or without eyeglasses by tilting my whole head and pulling back to get a straight on view of the edge rays. This minimized chromatic aberrations. The S-W's 78° AFOV and 7-11mm of usable measured eye relief felt way more comfortable with and without glasses than the Svbony's 60° AFOV and 8mm of measured usable eye relief. There's more to ER than what the measurements say with zooms/varifocals. I could still see the Svbony's AFOV receding away as I zoomed in. The S-W didn't seem to do this all that much. This made the Svbony's AFOV feel much narrower at higher powers than it really was. The Svbony's full field below 5mm is all but impossible to use for very long if you have long eyelashes like me. I had to mash my eyelashes in the eye lens surround area to see the entire AFOV at 3mm and 4mm, and it was very uncomfortable. I had to pull back on each eye blink to avoid getting gunk on the eye lens. With my 2.5 diopters of astigmatism, the views at 6mm to 8mm were subtly sharper with glasses than without despite the small exit pupils in the f/6 scope. The lack of parfocality of the S-W was far outweighed by the huge AFOV and slightly longer eye relief. Much more of the moon, if not all of it at lower powers, would fit in the S-W's AFOV giving a much more satisfying view. The Dob didn't care how huge and long the S-W was compared to the Svbony as far as balance. This might not be the case in a small alt-az mounted refractor, Mak, SCT, or Newt. Now I feel like I need to get the APM Super Zoom and pair it with a quality Barlow/Telecentric Magnifier to see if it would be the best high power zoom combination for my astigmatic eyes.

You could build a Roll-off Dob Shed.

Always browse in private/incognito/InPrivate mode while not being logged in. That way, no cookies get deposited on your computer long term. If you were logged into ebay, you're out of luck. It also prevents cross-site snooping by websites.

You make some very good points. When I've only got an hour to get outside after work and before bedtime to get up rested enough to go to work the next day, I simply don't have the time, desire, or patience to mess around with setting up and fine-tuning an imaging rig. If I lived in the mountains of New Mexico and had a permanent observatory imaging setup, I might feel completely different about imaging versus observing. I could actually do both at the same time using preprogrammed imaging runs. However, unless I was imaging something no one else had imaged in the same way, I'd have a hard time justifying doing it at all. I took a lot of snap-shot images through the eyepiece of bright objects starting out in amateur astronomy years ago and lost interest in it within a couple of years. Nowadays, I just enjoy communing with nature and the celestial sphere from the quiet of my backyard.

Any SAEP (kidney-beaning) issues when used on such a bright object? Any finickiness holding the entire field of view at once? I've read that SAEP is the main issue with the entire SSW line.

Just like camera lenses, high end prime lenses (eyepieces) generally stomp on entry level prime lenses (eyepieces). High end zooms generally stomp on entry level zooms. High end teleconverters (Barlows/Telecentrics) generally stomp on entry level teleconverters (Barlows). A high end zoom might stomp on a series of entry level prime lenses/eyepieces. It's a matter of comparing apples to apples rather than apples to oranges, just as in photography. Specific to your question on the Barlowed 25mm Starguider, it might perform similarly to the 12mm. It definitely would have much longer eye relief. By itself, the 25mm Starguider is a poor performer in the outer field in sub-f/8 scopes. The 12mm is quite good in comparison. Rather than degrade eyepiece performance, high quality Barlows generally improve the performance of marginal eyepieces by slowing down the light cone to within the design range of the eyepiece. Unlike photography, it is necessary to consider appropriately matching eyepieces to scopes based on the f-ratio of the scope and the design f-ratio of the eyepiece. Unfortunately, most eyepieces don't list their design f-ratio. Thus, you need to read up on eyepiece reviews in scopes of varying f-ratios to get an idea of how it might perform in your own scope(s). I have a GSO version of your scope; and at f/5, it is fairly demanding on eyepieces. If you move into wide apparent field of view eyepieces someday, you'll want to invest in a coma corrector for it as well to get the most out of your eyepieces.

That's a TS-Optics 90mm FPL-53 Triplet APO I bought a few years back. I've read it may be a Sharpstar scope. To me, the Hercules/Antlia 1.25" wedge looks like a 1.25" version of the 2" Meade, Starfield Optics, and Altair Astro wedges: Coincidence? I think not.

For the 14" SCT, I'd get the 40mm Lacerta ED. At f/6, it's nearly as good as the 40mm Pentax XW-R, with a bit less eye relief, but 3/4 the weight. At f/10, it should be nearly indistinguishable. Here's my comparison image at f/12 from my 127 Mak:

As I've said in other related threads, keeping my older eyepieces works well for my budding amateur astronomer daughter. I've already loaned her my eyepiece sets I bought just to compare them (Paradigms/Starguiders and HD-60s) along with lower end retired eyepieces such as the 30mm 80° Widescan III clone and 40mm Meade 5000 Plossl. As she progresses, I'll eventually loan her my retired 27mm Panoptic and 12mm/17mm Nagler T4s. She may also end up with the 40mm Lacerta ED or 40mm Pentax XW-R at some point. Yes, I've dropped over $600 on step-up eyepiece sets just to see how good or bad they are, and then report back here on them for your collective edification. You're welcome. 😄

I went with the Hercules solar wedge. Being 1.25", it doesn't take up that much back-focus. It works perfectly well. I ordered direct from them before China cracked down on retailers not going through approved marketplaces like AliExpress. It looks like their online store may be back up again. They're also available under Hercules and no-name versions on AliExpress here, here, here, and here. They're low cost, but work very well.

For me lately, it's been a combination of poor weather, lack of spare time, and sheer exhaustion keeping me from using mine. For a long stretch in the 2000 to 2012 time frame, I was too overwhelmed with helping to raise three little kids to get out much to observe. Luckily, I didn't sell my gear, so I was able to get back into observing relatively painlessly once they all became tweens or older. It was also good for at least one of my kids who took an interest in astronomy. The other two were too busy playing video games or dancing/teaching dance to be interested in astronomy. I had maybe 7 or 8 eyepieces, a few Barlows, and three scopes back in 2012. This has exploded to over 70 eyepieces, 8+ Barlows, and 7 scopes today.

I've been observing for about 25 years now. Being a bit of a hoarder, and not being hard up for money or storage space, I tend to collect eyepieces and compare newer ones to older ones as references. I'm sort of like the musician with 40 or more trumpets or guitars. Each has its own characteristics to be experienced.

It would have the spherical aberration of an uncorrected f/2.2 spherical primary, which is to say a lot. I've looked through an f/4 spherical primary Newtonian (Celestron FirstScope 76), and only the central region of a 20mm Plossl was barely usable. f/2.2 is going to be way worse. I'm not sure how much the camera corrector lenses would help with the SA.

From my online reading, the RASA does indeed use the standard SCT Schmidt corrector plate which is very nearly plane flat at the macro level.

So that's why you keep it in your pocket! We won't tell. 🤫

As I've said in previous, related threads, I love panning about rich star fields at lower powers discovering star clusters that are not at all obvious at higher powers. It's sort of like going out for a drive on an empty road and just enjoying the scenery instead of heading for a destination. It's just relaxing to have no particular observing plan which allows me to unwind after a stressful day.

You probably didn't have a vintage chemistry set with potassium nitrate in it. It was included for making a smoke bomb. Of course, it's also the main ingredient in gunpowder. I'm thinking they need to sell the Breaking Bad chemistry set to put the fun back into childhood chemistry: 😉

Especially if, like me, the observer uses filters from multiple manufacturers and even multiple generations from a manufacturer (looking at you, Lumicon). In that circumstance, there's little hope of parfocality across filters. I have been known to swing over to a nearby star to achieve best focus and then return to the nebula. This is best done in one axis if using an alt-az mount to make getting back more repeatable.