SimM

I can recommend the Beelink brand that has been sold by FLO, although specs change quickly, so J4125 generation CPUs are now N5095 for increased performance for a bit less expense. Mine is a Beelink U59 Generation with N5095 CPU, dual channel 16GB DDR4 RAM and 512GB of SATA storage with 5x USB 3 output. It's ironic that these little Mini PC can now support 3x 4K simultaneous video outputs, but for Astro use they are used "headless" after the initial setup e.g. no keyboard, mouse or monitor required. One reviewer had setup and reviewed the same Mini PC for Astro use and considered the performance more than adequate for data acquisition. I have rotated through two of the Mini PCs because the first one had 8GB of RAM and only one stick of RAM but was advertised as dual channel. The replacement had RAM and SATA storage both doubled and did work dual channel. In the space of one week the Windows 10 Pro (capable of Windows 11) has now become Windows 11 Pro preinstalled. I didn't have any issues with Windows 11 Pro and ASCOM 6.6 runs just fine. I did grab the latest Virtual Com Port (VCP) drivers from the chip manufacturers (FTDI and Prolific's websites) just to be sure. Power for the Mini PC comes from a 12V wall socket. They are rated at 36W but will need to supply only about 15-18W and typically run with much less than this. I want the CPU to complete tasks as quickly as possible and then do absolutely nothing until called upon to repeat the process. I did benchmark the two Mini PC and that's exactly what they do. The dual ranked one was quite a bit quicker and the advantages of the newer CPU would be wasted without two sticks of RAM. It seems that the manufacturer only supplies one module now rather than two 4GB ones with typically 8GB RAM. 512GB of SATA storage is plenty and for many uses even 128GB or 256GB would be adequate, but the Beelink can also take a further 2.5" SATA drive (or equivalent) so storage is practically unlimited. Although a Mini PC can be used for a replacement for a Laptop, I wanted to use it as a replacement for a USB hub and have it placed on the OTA rig. I have two PSU, one for the Mount and Dew Heater/Controller and one PSU for the Rig which includes the Mini PC. Some Mini PC come with a 19V PSU that are known to work at 12V, but his one has a 12V PSU, so can be operated without the supplied PSU wall wart supply for fewer leads if your PSU can provide sufficient power. The 12V socket is 5.5 x 2.5mm so the usual 5.5 x 2.1mm plugs may not fit. Performance of a Mini PC is surprisingly good. I did start off with a Laptop running Windows 10 Home and Chrome Remote Desktop but this required a table, plastic crate and Laptop with trailing leads across to the Mount and OTA. I have since used an old Windows 7 Pro license to "upgrade" the Laptop to Windows 11 Pro before getting the Mini PC. The Mini PC is mounted on the OTA rig and directly provides USB to the equipment, so the table and plastic crate and trailing leads are no longer a prerequisite. The quote TDP for the processor include the graphics processor so that actual use for Astro use is a fraction of the available power rating and the CPU drops back to minimise power usage when it's not required - if it's not needed then it's not used. At the moment I'm trying to provide a vented enclosure that will also provide protection from Dew and trying to get the Mini PC to automatically power up using a BIOS setting because I may not have access to the power button (anyone get this to work)? I'm also using the Microsoft Remote Desktop which I originally made work without a Windows Pro license. With Windows Pro it just works and I can access it from "inside" on an iMac, or "outside" from a Laptop or iPad. Running with an iMac, using the Microsoft RDP Application Client is particularly interesting and in test I could run a 4K YouTube Video with sound on the Mini PC with the display/sound on the iMac flawlessly with graphics acceleration provided by the iMac and the WiFi providing sufficient bandwidth. I also get to set a bigger resolution on the iMac than my previously attached PC Monitor. For Astro use the requirements are far less demanding, but I would caution about the misconception that "any old" Laptop will do. Simon

I did split it like this. A waterproof mains PSU box on the ground with an internal 3-pin socket for a WiFi extender. One PSU for a Dew Controller on the Mount Spreader Table - with 12V outlet for the Mount. Second PSU runs up to the rig where it splits/powers "everything". This is a 12V Mini PC, Focuser, EFW and main Camera Cooling. One "up" heater cable to the OTA Dew Heater and one "down" USB cable to the Mount. Both PSU run cool because the running power is far less than the often quoted maximum power ratings. The "secret" for cable management is to combine/distribute 12V Power and USB to the two "zones" with cables that are long enough, but not too long to get tangled. Simon

It was a clear night up to about 1:30 am and then ended abruptly with thick cloud seemingly to appear in an instant (so the forcast was right). So in the end I didn't manage to quite solve all my issues, so a "target" was a bit too much (this time). I had the L-eNhance fitted within the 21mm ZWO spacer that attaches to the ASI294MC. It was my first time with only a scope with a (noticeable) filter, but the experience of only having NB was (for me) a bit weird. I would have preferred the ability to switch filters, so I'll definitely be getting an EFW - even for OSC use, so that I have a "closed" environment to call up NB, BB or similar without having to open stuff up . Some tasks that are normally straightforward become much harder and difficult when that choice is removed. I've often thought about having a filter drawer or a manual filter wheel for OSC use, but just a few hours with only access to one captive (NB) filter convinced me that an EFW isn't really a luxury, especially as filters are pricey and need looking after. I did find that plate-solving worked very well even with the filter in-place. Also getting focused - I haven't so far, setup auto focus, but I could visibly check and adjust the focus OK and see HFR numbers as well. Considering how bright the moon is, the filter really helps with the background. So I'm both pleased with how it went but also a bit frustrated with some other issues not related to using the filter. I would have liked the ease of switching out the filter but I was reluctant to mess with it. With the placement of the filter inside my ZWO 21mm extension, there really is only one way round it can fit e.g. with the front facing the sky and the threads back towards the camera - otherwise it would clash with the sensor. Optolong had an article that about identifying the AR side of a filter and placing it towards the camera. For my two Optolong filters this would mean putting them with the threads away from the camera - which seems wrong? With an EFW it would mean having to put the motor side facing towards the sky. So not as the instructions suggest (or finding some filters that are the other way) or trying to reverse the filters in their holders. Everything points to filters facing towards the sky - so perhaps the Optolong article wasn't right! Simon

Indeed. I was keen to have a go with my L-eNhance filter, especially as tonight the Moon is pretty prominent (Waxing Gibbous) and only three days off a full moon. Normally I wouldn't consider this as being practical but I thought why not try NB! Target is the Rosette Nebula and NGC 2244. I followed all the suggestions to read on CN about ASI294MC issues and the L-eXtreme filter e.g. flats and colour casts, so perhaps I shouldn't push my luck and stick with what my instincts say might give trouble for little additional benefit e.g. very little upside and great potential for disappointment. The filter is 1.25" and very close to the ZWO camera in the ZWO extension tube in a small adapter. I will try to target the Rosette Nebula and NGC 2244 and answer the question of any issues with the OSC and filter position and of course my "somewhat dubious" newbie imaging skills. Simon

I have Scope - field flattener - extension tube - OAG - ZWO 21mm extension tube (with 1.25" adapter inside) - ZWO 294 camera. If I had a filter drawer (more for mono use IMHO) then I would replace the 21mm extension tube. So for me a filter drawer would be behind the flattener but not quite as close as the 1.25" adapter - this puts the filter very close to the camera sensor e.g. you couldn't opt to put the filter in from the other side of the holder it really is that close. The adapter has two small holes and so getting it out is really easy e.g. spin it round with an Allen key and you have a carrier to mount the filter. I like the arrangement because everything is inside and the setup is closed. Swapping filters isn't something you do every five minutes so either a filter drawer or a filter wheel are not something I want to go for considering it's a colour camera and mono isn't something I want to try anytime soon. I would like to use the L-eNhance or L-eXtreme for a pseudo SHO Hubble "look" although I probably won't get a SII filter for a while. Having the filter code to the camera sensor should minimise halos if they are a reflection of a reflection? As the filter is moved forward it exaggerates any issues is how I (misguidedly) look at it? I would like to use autofocus and did wonder if any NB filter affects this and if the L-eXtreme would make it even harder. Getting auto focus to work is harder than it looks so for me there are probably several issues to work through. Interesting that auto focus through the guider works and with an OAG the two focus is directly linked with the same image scale hence the guider sees the brighter image before the filter via the little prism. Any NB filter will cut down the light so would be beneficial in getting a longer focusing sub that averages the seeing and variability and so be beneficial? I have a trial of SGP Pro which I plan to get to try it, first I have to establish the focus zone and step size and other stuff for my focuser (and walk before I run).

I have a colour camera ASI294MC with an Esprit 100 F/5.5 scope and flattener. I'm also a newbie for imaging. Even so, I want to try using filters for narrow band targets - for me that is a new thing. Some choices in astro gear seem pretty clear cut, this one not so simple. I have a 1.25" UV/IR Cut filter for putting inside the 21mm extension tube that comes with the ZWO. Now a second filter to replace it. There is an adapter ring that is 1.25" to T2 that takes no back focus and places the filter right in front of the sensor cover. I bought a 1.25" Optolong L-Pro broad band filter with the aim of reducing sky pollution and the effects of the moon but without an obvious hit to integration time. I don't have any street lights and live about 5 miles from the nearest town and about 12 miles from the nearest large city. I'm not sure how to ascertain the true Bortle level but maps show it as Bortle 4 although I have my suspicions that it is higher e.g. closer to Bortle 5 in reality. I'm looking at trying narrowband imaging and was looking at either the L-eNhance or L-eXtreme filters. At first I thought it was simply a case of picking the "new and improved" whiz-bang L-eXtreme, but after reading conflicting views I'm not so sure. On the one hand, it is claimed to be night and day better but equally the question of halos artefacts crops up. So the question is how much benefit will either filter provide and are the side effects of the L-eXtreme something to live with in exchange for perhaps increased contrast on moonlit nights? I was lucky enough to be given an L-eNhance filter, bought from FLO but I'm considering returning it to get the L-eXtreme - if that is a better choice and the additional cost is not so great with this size. There are other filters like IDAS but they are not available in my preferred size of 1.25". My understanding is that a narrow band filter has good transmission characteristics in the pass band but still requires an integration time that is double not using a selective filter. Even so, the images I look at are considerably darker with the L-eXtreme so perhaps they need an even longer integration time? Some things I read about the L-eNhance are that it's not much better than L-Pro when helping out with Moon glow because it is already quite a wide pass band. Would either filter have an effect on the ability to achieve focus using a V curve (to help automate the process)? Are halos inevitable or are they a function of where the filter is placed and how far off-centre additional bright stars are? The choice to me is different to someone who was thinking of upgrading and taking a hit on the resale value (thanks FLO). I am pretty confused as it's not obvious which of the two filters would be best. My original thought was to play it safe with the L-eNhance. False logic said that if I could use the L-Pro for normal targets then for NB the l-eNhance would be a good choice (if only having one filter that is available in my preferred 1.25" size). A few clouds later and I'm considering was that best. If I lived within a City the choice of cutting excessive light pollution vs getting artefacts would make the decision skewed towards the L-eXtreme. Is Bortle 4 or Bortle 5 a pivot point for which option to go for. Simon

I read the manual with interest. Typical of BP there is lots of detail and the company is always responsive to questions. From the operating procedure and description, it looks a lot similar to a Quark Chromoshere, e.g. an etalon with mica separation plates and a source of heating to vary the separation of the plates. The heat up time and adjustment time is quoted as 3-5 minutes. When I tried a Quark, it was around 8 minutes to setup and about the same to shift one band. One difference is that the BP requires the temperature offset to be set rather than having presets, so greater control with some added complexity. The operating principle also requires a tele centric Barlow and operation at around F/30. There are stipulations on the DERF or filter required depending upon the scope and some caveats like not connecting the supply wrong or using the control to exceed the preset by too much e.g. 10 C - why not limit the operation on the controller? BP products, whilst never cheap, are usually well thought through. Some competition in the market place is also a good thing, too.

Insurance companies have a way of looking at a claim and weaselling out if it, if they can. If the scope/mount/camera/power/computer was a bicycle - it wouldn't image very well, obviously. Like a bicycle, they might want proof that it was secured e.g. can't lift it and carry it away easily (open to opportunity)? Similarly with a scope/mount, they might want some evidence of it being secured e.g. locked to a ground spike etc. If you could show that it was forcibly removed e.g. tools were used to remove it, then a claim might be successful. Another problem might be that the insurer says that it was unattended and open to theft - like not locking your house before a burglary - no forced entry to show otherwise. Perhaps the best you might hope for is that an insurer may settle with a partial (percentage), somewhat in your favour. Or it's a risk you just have to accept. Of course, having insurance might also mean that you would never need to make a claim because that's how it goes (best scenario). After a claim, they would perhaps increase the premiums so much that any benefit was later forfeited. Short of tying a cord to your scope and big toe and sleeping in a tent nearby, there might not be too much to do, to protect it. Simon

I looked at your astro solar images and decided that there really was (for me) no need to go up to an 80DS. It will of course take quite some considerable time to reach the same level of imaging proficiency, too! £1900 is a good price S/H for 60DS compared to UK new prices. The problem in the UK is how the dealers get their supply. Bresser.de import to Europe and Bresser UK supply the dealers like FLO. So they have no option but to charge extortionate prices. FLO (and others) are not the problem here. The price hike compared to buying and shipping to the UK, paying VAT and Duty is a whopping 60% uplift. At those prices, I think it kills the market in the UK for Lunt products stone dead, IMHO. They are (for me) arguably the best product of their type.

Short answer is that I don't think you can go too far wrong with either option e.g. Lunt 60 DS or 80 SS, for about the same outlay, but YMMV. I have a 60 and DS, but used for less than a week. I had the same question e.g. SS 80 or DS 60 for about the same expense, back in February when I placed my order. There are DIY solutions to use smaller etalons with larger optics and there are other options like a Quark on an existing scope. I did spend quite some time and decided that it was better to forgo aperture for DS. Otherwise, I think the DS will be a later addition (I nearly wrote addiction!). I did briefly own a Quark, which had a fault with the main cell - there was a line almost directly across the middle (so much for quality control) and the PSU would give mild electric shocks - worse on damp grass (but it was only mildly irritating and I'm still here). It was returned for a refund along with an expensive UV/IR filter. A secondary disadvantage of the quark (for me) on my 4" scope, was only seeing a partial view of the sun - which I found disorientation and no option to "zoom out". For best operation about F/25-F/30 is required. So, using the objective/EP calculators isn't the whole story. I now others have been through a sequence of Quarks, trying to find a reasonable one, but I simply don't have the patience for this. The DIY option is something that always exists, although I wouldn't want to do anything that I later regretted. Experience learned the hard way with solar might not be advantageous? The reason that solar scope are so expensive comes down to the cost of making etalons. Using Lunt as an example, doubling the size of an etalon increases the cost roughly 4 times. A blocking filter and etalon as an addition can be about the same as a whole scope. The blocking filters also increase. On a 60 the sun is about 4.2mm across and in theory a B600 filter would be OK, but in practice a B1200 is better especially for imaging (not tried imaging so far). There are also different focus options that bump up the price. I have the R&P option and don't have (so far) any regrets. I don't have experience of an 80, but the image size is not vastly different, so as the B1200 is more than adequate, I can't see a reason to opt for an 80 with B1800. It may be beneficial because of the DS arrangement, I just don't know. A 60 DS is different to an 80 DS in that the 60 uses an internal first etalon and a front mounted DS etalon. On an 80 there are two internal etalons. The advantage of the internal etalons is that they can be made with smaller diameters. Like an EP, the telescope resolution is a function of the objective diameter and not the EP or intermediate lenses used. Internal etalons use two additional lenses to spread and converge the light path so that the light passing through the etalon is exactly perpendicular. A disadvantage of two etalons close together is that the second etalon doesn't throw the shadow of the first one away. This effect can be mitigated to some extent with an additional filter, as a mod? The 80 uses the same DS as the 100. So if you feel like upgrading to a 100 you save some money! There is also the option to use a front mounted DS on the 100. Clearly a better option, but realistically, since it's a big piece of glass, it also comes with a 4x price hike. Talking with Lunt, it doesn't seem that popular e.g. only a handful have been sold. Another option is to use a 60 with a 50 DS, but perhaps buying the 50 to use with a 50 DS would yield approximately the same result? Quite popular but it depends on what you want. Another factor to consider is the weather - aperture matters greatly with night time viewing where photons are in short supply, but for solar, there is an abundance from our neighbourly star, so like solar film and ND filters and wedges etc, brightness isn't an issue. The resolution is a direct function of objective aperture. In theory it is linearly related but it is perhaps a bit more than that. So an 80 should be a bit more than 4/3 improved. I wouldn't be too concerned about aperture because seeing conditions also greatly affect what you see. I reached the conclusion that there is no short cut (or cost saving) as what you pay (pretty much) determines what you will see. Etalon quality does also greatly depend on which supplier you opt for. In some ways, it is remarkable that you are able to buy a solar scope anyway as it's not the easiest thing in the world to make and there isn't much competition. What you can buy today was also prohibitively expensive in the past and internal etalons have really made that achievable as most folks have budget constraints. Still very expensive, relative to some other parts of the hobby? Etalon quality may also be a factor that is more important than absolute aperture. One reason to buy S/H is that you are often able to "try before you buy". I have a Lunt LS60MT and 60mm DS with B1200 R&P and no regrets (so far). I haven't needed to "throw in the towel" or use a towel and the image, especially as SS is very bright. The FL is shorter than previously used, now F/7 vs F/8.2 too? I haven't (so far) converted the scope for white light or night time - it is modular. It is marketed as 60mm but the front objective is a 70mm. There may be a field stop that limits the light path as it passes through the etalon section? I'm just coming to terms with how small the whole setup is. Compared to a 100mm Esprit the weight and size are tiny (a convenient - good thing). I carry an EQ6-R Pro mount into the garden and then attach only one (of two) counterweights. The scope is not unlike a finder (it isn't but seems that way) so is very easy to put on the mount. I also have the Lunt 4" long dovetail - balances very nicely and the DS doesn't upset things. I'm not compelled to swap out the dovetail for a green 6" SW one that I have (somewhere). I do have a Televue Sol Searcher - arrived from FLO yesterday. Finding the sun isn't so hard without one. Simply set the mount north, key in the sun and it slews almost to the right direction and then using the shadow of the sun shield (4" long black ring on my version) and notice that is is 4mm wider than the body. If you equalise the shadow on the clamshell on two (ideally 4 sides) to also be exactly 4mm (and balanced) and you are looking at the sun in the EP. I have the Lunt zoom, on the widest view the sun fits comfortably and zooming in from there. I can use other EP but the hassle of switching them offsets any potential gain, IMHO. You can of course get lightweight mounts that auto align but I'm happy with a heavier mount (that I already have). Using the PT doesn't affect (move) what you see with the bigger mount, but YMMV. The Sol Searcher is (to me) an interesting/useful addition - pending the lack of clouds we have today, of course. The previous version of the 60 (also the 80 or 100) were dedicated to solar use. The new modular system provides for other uses. I originally thought this was a gimmick because the cost of doing solar is quite high and most astronomers will come from another setup e.g. already have a larger scope for night time or white light. I am however, coming around to the idea that you want several options during the day e.g. h-alpha and wight light (wedge) or h-alpha and C-aK. Whilst you could use one e.g. AZ mount and two scopes simultaneously to do this, the option to switch over and use one scope and one mount is much simpler, IMHO. I haven't tried it (so far) as you have to swap 6 grub screws for 6 finger screws (provided) and then (others have said) the time to swap over is about a minute. On a 60 the etalon (red part) is removed and the focuser reused with the blocking filter/diagonal exchanged for a white light or C-aK e.g. I will use my BP Herschel Wedge. On an 80 it's similar except an (optional) separate focuser can (needs to) be used. I don't see a need for using the scope for nighttime use because I already have a 4" APO, except that for very wide field it might mean that I can get an even wider FOV with my existing colour camera using the 70 scope. For me, the benefit is the convenience during the day. Lunt do market their new modular scopes as being 0.65 angstrom vs the old 0.70 angstrom. I wouldn't be sure that this isn't anything other than "marketing speak" e.g. taken "with a pinch of salt". Simon

Does the LS60 allow the modular scope to be rotated independently of the collar and the internal etalon? So (now) no longer a need for a “rotation device” for the front etalon? What does “clocking” achieve?

@Minhlead - Sorry to hear that it didn't work out with the Quark. Getting a refund was probably a very good outcome even if you are a little out of pocket. My experience with a Quark also wasn't good. Ordered from a reputable UK Dealer, product was delivered and looked to be well made. At the beginning of January there was too many clouds to get outside but I did try the supplied PSU and the Quark - seemed to heat up in about 8 minutes and switch bands in 6 minutes. There was however an issue with the unit - pick it up and you get the impression that it is vibrating. It turns out that the PSU leaks a small current and the mechanical vibration is a mild electric shock. 230V AC in the UK. A multimeter confirmed that there was 93v AC on the rivet on the side and the current was 20 uA. That is 1/1000 of what can be regarded as "lethal". I did experiment with wrapping the unit in clingfilm and also notified the dealer about getting it replaced. When the clouds did clear, I did some WL with a Baader wedge and then switched in the Quark. With WL I tend to centre the Wedge with the EP removed. I tried the same thing with an EP removed from the Quark. That's when I noticed a second defect. The image of the Sun looking through the etalon showed a line that was half the width and from the top to the bottom relative to the adjustment knob. It wasn't on the front or the back and only visible when looking through it with the Sun. At this point my patience was wearing thing and knowing the problems of getting things replaced (over and over), I insisted on a full refund - received. I also had the recommended UV filter refunded as it was bought specifically for the Quark. With Quarks, you kind of know that it is a bit of a lottery. The odds of getting a good one are (like the lottery) slim. So I'm probably guilty of wanting to believe it would be OK, but knowing that isn't going to happen ("he looked confused for a moment, then suddenly the penny dropped"). So, I'm now moving in the direction of acquiring a Lunt scope. Simon

It is certainly not a reason to change what you know works - "if it ain't broke - don't change it". Sort of "chicken and egg" as well, as there are not many users to get opinions about it, to get interested in it. The "gimmickry" is OK, but I can see that many astronomers will probably be already starting with some existing equipment, anyway. Simon

Thanks Steve for the cutaway diagram. See the mods to the LSMT60. They use the same red front-mounted 60mm clear etalon as the outgoing LS60THa. The scope is 420mm f/7 with ED doublet FPL-51 replacing the single objective and not coloured. As a normal scope it's 420mm f/6 (uses full 70mm objective). It's anyone's guess if they improved (or cost reduced) the scope. Claim is < 0.65A or < 0.45A. So, at least there is one front mounted-etalon in DS configuration (a good thing?). Simon

This is the result of stacking a video of images? What you see with an EP doesn't compare to it? OR does your eye only capture the good moments (or probably averages it and sees it as worse?).

I have started using Affinity and I couldn't understand why changing colours had no effect - until I switched to a colour space! It was the same first time a tried to use a toaster - so much more fun when plugged in - LOL. I did find the prominences look good against mid grey background but the reddish background makes a "powerful" statement in your coloured image. Simon

Lovely image. Do you "tweak" every image with moving sliders on a curves dialog or do you have some kind of preset that you use? Is the colour around the sun achieved with the same "tweak" or is it different on the outside? It must be different because the starting point is shades of mono and all are in the inner part too? For a "natural look" would you be aiming to not have the outside totally black e.g. grey or something else shows up the prominences?

Is the blocking filter operating like an ordinary 1.25" filter that you might put next to a ZWO sensor (except it blocks and is smaller e.g. B600 is 6mm and B1200 is 12mm diameter)? Is it after the diagonal on the EP side? Tracking an object accurately for a reasonable time isn't so hard with an equatorial mount, even when only roughly aligned as would be the case in the daytime (from trying a solar wedge for WL). So, to use the example image from above, the sun is 4.2mm and the sensor is 4.9mm x 7mm. A blocking filter that is not close to the camera sensor and that is only 6mm seems a bit borderline e.g. won't it vignette the camera sensor if it isn't sufficiently close to the camera sensor and that's why they recommend a bigger version for imaging. Or is the path of the light from the objective, through a positive and negative lens that causes it to pass "parallel" through the Etalon and also the blocking filter e.g. vignetting of a cone of light e.g. an f/4 or f/7 refractor, no longer applies? Since the target is only ever fixed then there is no reason to accommodate two or three suns. By the same reasoning there would be little point having a zoom e.g. the 7.5mm - 21mm that will show about 1.25x - 3x sun diameters for visual use? So apart from zooming out to find and centre the sun, you would always want the 7.5mm end of the zoom? OR is (likely) it more comfortable to use a lower power EP than need not completely fill the FOV? Except, I notice that it's often recommended to use a 10mm or 12mm EP with the 60 Lunt scopes? I'm not a fan of zoom EP but I can see the wow factor of zooming in with ease for this "special case" target. I ask because the cost and benefit increases of having a bigger blocking filter are good to know and because I was considering using a fixed EP rather than the zoom e.g. a 10mm or 12mm as recommended with an existing 17mm or 21mm for the find/centreing exercise. With the smaller blocking filter there would be nothing additional to look at with a longer EP or with a small sensor to see? Simon

An astronomy scope is designed to do one thing well, focus at infinity. Anything else is a bonus. Spotting scopes are more like other optical instruments... so, camera lenses, binoculars and other optical instruments are designed to focus at roughly 10x the focal length to infinity. That's a compromise that isn't needed for astronomy. You can see other compromises e.g. an SLR has to allow a mirror to flip up and down, so the design of the optics becomes much more difficult e.g. a wide angle lense has to have elements to overcome these difficulties. Zoom lenses are another compromise where a prime lens does more with less. One advantage might be that the market for spotting scopes is much bigger and the costs to design and manufacture are lower.

Unless the mirror is very old, it won't be silvered. It is more likely that it is aluminised and there will be a hard overcoat to protect it, so not easily damaged.

How good is a William Optics Gran Turismo GT 102 Triplet Refractor with a WO x0.8 Reducer Flattener 7A for AP?

If you are going to put a PSU in a drybox, then it makes sense to put all the mains plugs and sockets in the drybox as well e.g. no point in the PSU being dry if the plug is in an extension reel that is outside.

Same issue, might happen on any scope/rings combination? Point to the zenith and it immediately starts to slip. Adding a 2cm width of A4 paper between either ring and the scope, adds little to the overall diameter, but shows that little additional friction is required to prevent the scope sliding. It's not a permanent solution.

I would like a pier and even an observatory in the future. For now it's a (more) stable base than just the lawn and a repeatable position (like on a decent patio). I'm probably not going to want to leave the mount outside, so it's inevitable that polar alignment will have to be redone. I can do a Polemaster + 1 star alignment quite quickly. MOT is good "stuff" and I just want a firm base and a location to do a quick alignment tweak. At least if I did eventually go down the pier route, then I will have verified the location. An observatory is also a longshot e.g. unlikely.

A Reducer that is 0.65x is more "difficult" to get right than a more modest 0.8x and the image circle is reduced e.g. 0.65x X 43mm vs 0.8 X 43mm vs 43mm (not reduced), so a Reducer is not a "magic" panacea. Cropping the image is both wasteful of the camera sensor and cropping an already smaller FOV is limiting and wasteful, considering the starting size of aperture. So I see it as an additional and very useful addition for 120/150 owners. 100's are a good match for your EQ6 sized mount for AP, so there is something for everyone.