Jim L

Gorgeous!

I don’t know Mike’s motivation in sending this latest email, but if I were to guess I’d say it’s just as he says, (it’s) “Just something I’ve been thinking about.” I don’t see any ulterior motive. I’ve spoken with Mike on the phone, and my take is that he is a thoughtful person who believes strongly in doing what’s right in preference to what’s easy. Case in point: Mike ships his gear protected by starch based biodegradable peanuts. I’ve priced those peanuts and they’re very expensive in comparison to the more common forever plastic variety. Mike could easily ship plastic and pocket the difference, or brag that he’s environmentally responsible, but he doesn’t. I’ll bet his additional annual cost in shipping biodegradable peanuts runs well into the six figures; money coming out of his pocket. Mike simply does the right thing, and apparently that’s all the benefit he needs. I think Mike loves amateur astronomy and is sharing his love in the manner that works for him; which is bringing the best scopes he can at the best prices he can to his customers. I’ve also dealt with other companies driven more by what’s expedient to their bottom line; I get a completely different vibe from them and Mike’s not like that. I’d guess the email is simply Mike musing over the nature of his business, it’s future, and it’s relationship with its customers, whom he actually cares about. His is a business founded by his father and that has been in his family ever since. I expect that for Mike it’s personal, and in his blood.

I subscribe to several amateur astronomy company blogs and emails, Astronomics among them. Today I received this very interesting email from them that I thought worth sharing. I have no special relationship with Astronomics other than being a customer, but in my own dealings with them they have always been fair and honest to a fault. I hope you all have similarly excellent experiences with your own companies in your part of the world.

I dry mine for 2 minutes at 700w, flip them around, and repeat for another two minutes. It’s the excitation of the trapped water that creates the heat so you want to be sure there’s plenty of air around the pack for the released moisture to escape. As the water is released, and there is less of it available, they don’t get as hot. One pack melted the plastic plate I placed it on, so they can get very hot. My packs have a bag that is made of material much like Tyvek, which is very tough. The bigger danger to my packs is that the silica gel balls can fracture and that might not be good for them, but I keep within the products instructions and so far, other than the melted plate, everything has been fine. It may be that all packs aren’t created equal, and some may not be as suitable for microwaving. The packs that shipped with my Takahashi scopes did not dry in the microwave, which suggests to me that they weren’t made for reuse. If the packs don’t claim to be microwaveable proceed with caution. In your case I’d use half the wattage and let them rest for a minute between heating.

I had my AT72EDII out last night looking at a variety of night time objects across the sky including bright nebula, open and globular clusters, galaxies, and double stars. Included with my kit was a SvBony 3-8 zoom and a SvBony SV135 7-21 zoom. I started out with the 7-21 zoom but while teasing out one of the tighter doubles switched to the 3-8 zoom. I hadn’t used it in a while and so was very pleasantly reminded at just how handy and capable an eyepiece it is. The views through it were sharp and relatively distortion free, and it facilitated finding just the right magnification for the object and seeing. It’s not perfect, and my biggest complaint is that it’s stiffer to turn than I would have liked, but beyond that and at its current sale price of $120 here in the states, it’s an absolute bargain. I had with me several wider field eyepieces, but last night as I hopped from object to object the two zooms with their combined focal length range of 3-21mm were all I used or needed. If you’re on the fence about the 3-8 I’d suggest giving it a try and while you’re at it grab a SV135 zoom as its complement. They’re perfect for a lightweight travel kit.

Here are the larger 112 gram microwaveable desiccant packs, which weight in at 114 grams dry. These will go into the four of my larger Pelican cases. They cost just a bit over $4 per pack and recharge in under ten minutes. Based on the smaller packs they should remove up to about 60 grams of water, or five teaspoons worth, before they need recharging. Here’s the source: https://www.amazon.com/dp/B0876TS3RJ?psc=1&ref=ppx_yo2ov_dt_b_product_details

Beautiful photos, and amazing details!

Once desiccant packs reach their water storage capacity they no longer provide protection for your optics. Fortunately, many desiccant packs can be easily dried within a few minutes in the microwave. Here’s a 50 gram (52 grams including the porous bag) pack that’s taken on 12 grams of water, or about 2.4 teaspoons worth; it’s full and no longer provides any further protection. The dark spots are beads that turn dark as they absorb water. This pack is microwaveable and I put several into the microwave at a time, taking care to arrange them so that the released moisture has a way to escape. The small packs that came with the Takahashi didn’t change weight after microwaving which means they are not rechargeable and so I discarded them. A few minutes later 12 grams of water have been removed and the rechargeable pack is ready to back into the case. Here’s the case humidity before adding the desiccant pack: The case internal humidity a few hours later that evening, and a very inhospitable environment for fungus: The little hydrometer will let me know when the desiccant package needs drying, which is usually within one to three months depending on conditions and usage. There are plug-in rechargeable desiccant packs but purchase them with caution. Many of them contain very little active ingredient in comparison to their weight, bulk, and cost, and can take hours to recharge; I don’t care for them. Here’s the microwave rechargeable desiccant packs I use: https://www.amazon.com/gp/product/B07TCGPZXK/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 They also have 112 gram microwave rechargeable packs which should last twice as long between recharges. And here’s the little hydrometers I put in each of my cases: https://www.amazon.com/dp/B08P3QJJZL?psc=1&ref=ppx_yo2ov_dt_b_product_details

Thanks, Wookiee. Most of my achromats work that way, and I use that method often, but this was a different situation. The doublet glass in this particular scope is held in alignment within its cell with eight grub screws (four each element), and was correctly aligned within the cell. What appears happened to my scope is that the mating surface between the lens cell and optical tube was very slightly compressed on one side due to the sideways impact of the scope on the pavement. I came to this conclusion by observing that collimation went wonky in the instant the threaded in cell seated itself against the tube, and not before. Back to inexpensive achromats for a bit, misalignment between the focuser, lens cell, and telescope tube is a common problem when the cell and/or focuser are secured to the tube with Philips head screws, like my ST80. The contact surfaces between the tube, lens cell, and focuser often aren’t sufficiently precise, and collimation suffers as a result. Most recommendations are to put a bit of a torque on the misaligned part to bring it to collimation and hope it stays that way when the affixing screws are tightened. I’ve had mixed results using that method and even if collimation is achieved it’s very susceptible to being lost with the slightest bump because the parts aren’t fully seated and in support of each other. Correcting the mating surface between elements so that the fully seated elements are in correct collimation makes that collimation robust, permanent, and repeatable. It’s not all difficult to do and requires nothing more that what’s shown in the photograph and a Cheshire eyepiece.

My AT72EDII 72mm refractor took a bit of a tumble when I knocked my setup over jumping up to face what I thought might have been a mountain lion but which was actually probably a small mouse foraging in the dry grass. The fall didn’t misalign the doublet lens within the cell, but the threaded on cell was no longer square with the optical tube. By loosening the cell and rocking it with my hand I was able to achieve proper collimation. Using a set of feeler gauges I found that a 0.35mm gauge placed at the right location would level the cell when the cell was tightened. I marked the opposite high side with painters tape and went to work lowering the marked side using sand paper taped to a piece of glass plate. I sanded a bit, reassembled the scope, checked my progress using a Cheshire eyepiece, and repeated the sequence as necessary. Five easy minutes later collimation was perfect.

They can be handy for aligning the secondary axis with the center mark on a Newtonian, and for checking the focuser alignment on a refractor. Placed into a Barlow a laser can also be used to align the primary mirror axis with the focuser axis. Without a Barlow the results can be far less reliable. So I’d say yes, it’s worth having. You don’t really need anything super fancy, but be prepared to collimate it if it’s not well aligned. Alternatively, a combination sight tube like the one sold by CatsEye is an excellent choice, and adds the capability of centering and squaring the secondary mirror in its holder.

The secondary mirror holder and mirror mods are completed. For reasons unknown, here in the states it’s nearly impossible to purchase 1-3/4”x 1/4” washers unless you want a 1,000 or so. After fruitless searches for the proper size in more reasonable quantities I picked up a 2”x1/2” washer. A few minutes with a the grinder, lathe and flat file later: The aluminum bushing keeps the washer centered; it’s an interference fit in the washer so it’s unlikely to come out of its own accord. The other side of the bushing is wider, and provides a platform for the mirror holder spring, like so: The spring will further ensure that the bushing never comes out of the washer. Here’s how it stacks in the mirror holder: I chose to not include a HDPE washer as the polished thumb screw ends will not cut into the washer, the setup as shown is very precise and is as solid and immovable as Gibraltar, and the extra washer is superfluous. Last on the list was darkening the side of the mirror. As delivered the mirror side facing the focuser looks like the core of a globular cluster with thousands of sparkling points of light. That can’t be good for contrast so I picked up a chisel point Sharpie and gave it a good blackening. I chose the non-waterproof version since I know it can be removed easily with isopropyl alcohol if desired. You definitely want the chisel tip otherwise it will take forever to coat, and the chisel tip lays down nice, thick, ink. All together, collimated, and ready to observe: Total cost, including the stainless steel thumbscrews, was around $12. I went back and blackened the edge of the washer after I took the photograph above, though it would have been easier had I done it before the holder was mounted. One final thought: the screws throughout the scope aren’t the self destructing Phillips head type, they’re JIS (Japanese Industry Standard). If you use a proper JIS screw driver you’ll be far less likely to round the heads and everything will come apart and go back together much easier and with less drama.

The voice of experience, perchance? 🤔

My wife, who researches these things, tells me it’s a Northern Pacific Rattlesnake. Much like us they’re nocturnal, and not aggressive, but they will bite you if threatened or cornered, or if you accidentally step on one while listening to your favorite Astronomy podcast. They’re third on my list of wild animal concerns, below mountain lions and bears but above wild boars.

Almost stepped on this handsome fellow at an observing site. He was buzzing away but I never heard him because I had earbuds in listening to a podcast. Fortunately we parted friends.

At f/10 and with a chromatic aberration ratio of 3.63 chromatic aberration should be reasonably well controlled, but I like Louis’ idea of experimenting with filters to see if you can get even more out of it. I’m a big fan of the #11 filter in fast achromats because it gives noticeable improvements without causing an egregious color change through the eyepiece like the #12 can sometimes do. In any case, it looks like an excellent loaner scope for your astronomy curious friends and family.

Monica and I had her 10” Dob out for the first time last night at my favorite observing location. We were too excited to remember to take a photograph, but here’s one from an earlier session showing the view to the south: We’re working on the Messier objects so we began our evening with the Leo Triplet followed by numerous galaxies in the Virgo Super Cluster. Seeing and transparency so so, but the views were still spectacular and galaxies were everywhere. Monica’s favorite constellation is Scorpius so next up were Ptolemy’s Cluster and the Butterfly Cluster, and then M22 and the Lagoon and Trifid Nebulas in Sagittarius. The biggest surprise of the evening was the globular cluster M4 in Scorpius. We had a look at M4 through one of our 4” refractors from our light polluted back yard the evening before, where it was the dimmest of smudges only visible with averted vision, but through the Dob, under darker stars, it was a mass of hundreds of resolved stars easily enjoyed with direct vision. That was a very pleasant surprise and confirmed our decision to purchase her new scope. All in all a great evening under the stars.

Thanks gentlemen, a hardened steel washer and HDPE disk will be included. I purchased stainless steel 4x30 mm thumbscrews shipped for less than $10 from a well known PRC market place, and I reworked the screw ends. A CatsEye combination sight tube, autocollimator, and Cheshire eyepiece are scheduled to arrive tomorrow. I’ll complete the mods to the secondary holder that evening and begin work on the primary cell afterwards. The primary cell will have its collimation screws replaced with studs and through thumb nuts, the fan will be shimmed so it sits a few more millimeters from the mirror, and the back of the cell will get a fitted cover to better direct airflow. Next will be some minor tweaks to the mount.

For those interested in beginning solar observing the Actual Astronomy Podcast’s most recent podcast is largely about solar observing and how to get started. https://www.podbean.com/ew/pb-tf9rc-143257f Chris often discusses solar observing so it might be worth perusing their other podcast releases for additional advice and information. As always when observing the sun through a telescope, don’t take any chances or shortcuts, and redundant in favor of safety is your friend.

Essentially that’s what I did, but instead of a chunk of iron that serves no other purpose I substituted the fan battery. The Velcro strip is long enough to allow the battery/counterweight to be moved up or down as required to achieve balance.

Most of our scopes have several set screws to assist in collimation or to hold diagonals, eyepieces, or other gear in place. One of my favorite and most effective fixes improves the function and reduces the damage from set screws, and costs virtually nothing but a little spare time. The problem with most set screws, grub screws, set bolts, etc., is that the unfinished end of the screw usually takes the shape of whatever results from the screw being cut from its origin material. That surface is often sharp and it deforms, or worse yet cuts, the surface it is tightened against. The more the screw deforms the opposing surface the less effective the screw is in securing it. The solution, fortunately, is relatively easy and entails shaping the screw end into a nearly flat but very slightly convex surface using nothing more than fine abrasive paper or a knife sharpening stone. On larger bolts, like the primary mirror cell lock screws, I begin with a fine abrasive paper placed upon a flat surface. Holding the screws in my fingers, I move the end of the screw over the paper or stone in small circles, occasionally rotating the screw to avoid creating an angled surface. Rub in circles, rotate, repeat; a drop of cutting oil helps. Before long the sharp edges of the screw ends are eliminated and a very effective and non-damaging contact surface is generated. The photo below shows the three primary mirror cell screws in varying stages of modification. The left most screw is as it comes from the factory, the right most screw has been partially shaped, and the center screw shaping has been completed: Here’s a closer, albeit poorly focused, view of the same three screws: Smaller screws respond equally well to reshaping and here are the secondary mirror collimation screws in various stages of reshaping: In the case of very small grub screws, rather than hold them in my fingers I insert an Allen wrench or hex driver in the hex end of the screw and use it to hold the screw against the stone. Remember: circles and rotate. Here’s one of the finished parfocal grub screws within its ring: The very slightly convex contact surface created by rubbing the screw against the abrasive surface in circles, and by rotating it, holds the ring without damage to the eyepiece barrel and requires less tightening in the bargain. I reshape every set screw on all of my telescope gear. It only takes a few minutes and the improvement in the function of the screws is surprisingly large.

So you just bought your wife a very nice new 10” Dob, the weather’s gone to the dogs, and the gods look with contempt upon your pleas and sacrifices for clear stars. Oh yeah, you’re also broke. What now? Cheap and easy tuneups, that’s what! Some of the following tips are specific to 10” GSO made Dobs, but many are universal, so let’s get started. 1) Rotate your focuser. There are two grub screws that when loosened will allow you to rotate the focuser to whatever position you desire. The location of one of the screws is shown with the blue pen below, the other screw is directly opposite: Here is the focuser repositioned: 2) Red dot finder shoe: Finding objects with your Dob will likely be easier if you attach a lightweight red dot finder. I found a mounting shoe in my spares and picked up a super light but effective red dot finder for around $15. I didn’t want to drill any new holes so I used a couple of thin strips of 3M double stick tape to attach the shoe: Here the red dot finder is installed between the focuser and the shoe for the 8x50 RACI finder. That 3M tape is strong, and the finder isn’t going anywhere: 3) RACI Finder cross hair delete. I was using the 8x50 finder to search for M13, which in my skies is very dim, and I found the cross hairs in the finder field to be too thick, too dark, and more often than not a distraction. They were particularly annoying when they completely blocked the desired target from view. The solution was to unscrew the eyepiece and to pluck out the cross hair wires with a pair of tweezers. With the cross hairs deleted I can more easily find the objects I’m looking for, it’s just as easy to center the target in the field, and using the finder is far more pleasant! Sorry, no photos. 4) Eliminate the need for the 2” 35mm extension. Some of my 2” eyepieces wouldn’t come to focus without the included 35mm extension, but swapping eyepieces, adapters, and extension was inconvenient in the dark. The solution was to install parfocal rings on the 2” eyepieces, and to adjust the rings to make the 2” eyepieces parfocal with the first 1.25” eyepiece I usually go to when switching from 2” to 1.25” eyepieces. First, install the 1.25” eyepiece you want the others to be parfocal to. Focus the telescope at a distant object and then lock the focuser in position by tightening the screw shown below: Next, remove the 1.25” eyepiece and adapter and install the 2” eyepiece with a parfocal ring loosely installed and the eyepiece holder set screw loosened. Focus the eyepiece by sliding the eyepiece barrel in and out of the focuser until the image is sharp. Do NOT turn the focuser knobs. Tighten the eyepiece holder set screw to secure the eyepiece in the focused position: Finally, slide the parfocal ring down the eyepiece barrel until it rests atop the eyepiece holder, and tighten the parfocal ring grub screws. This eyepiece will now be parfocal with your 1.25” eyepiece. I got my 2” parfocal rings from Astromania via Amazon, but FLO also stocks them: https://www.firstlightoptics.com/adapters/astro-essentials-parfocal-rings.html 5) Battery counterweight. You’re most likely going to need to add some weight to your optical tube to balance your heavier eyepieces, so why not use something you’ll also likely need as that weight, like your fan battery pack. I placed a self adhesive strip of extra strong Velcro along the bottom tube seam and the mating strip along the back of my battery pack: I affix my battery on the underside of the tube because it better offsets the eccentric load created by the focuser and finders: That’s it for now, I hope some of it is helpful, and I’ll have more to follow.

Nicos, I’m glad we see eye to eye on the things that matter, and here’s to more sublime scopes in our future, wherever they may come from.

Ratlet, I’m certain that your Stellalyra 10” is the same Scope as the Orion Skyline 10” scope I ordered this afternoon. I hope you had an enjoyable evening observing the moon and in solidarity with you I will also forgo a quiet evening indoors and have a peek at the moon tonight.

Thanks, Gerry. Louis mentioned the Explore Scientific version earlier and I expressed my concern those exposed trunnions wouldn’t hold up to my clumsy handling, but I did look it over carefully. I really like that the mount uses quick-connects so that it can be easily disassembled and assembled for transport, but I was less impressed with the short travel of the focuser that some owners complained necessitates the placement and removal of a threaded on adapter when switching between eyepiece sizes. I’m sure it’s a fine instrument, but not necessarily the best for my purposes.