AstroTim

Looks like you might have captured Callisto transiting Jupiter. I’ve just been observing that visually. Tim

I’ve also been looking into getting a filter drawer for visual use and have had the same thoughts as you. I currently use a manual filter wheel, but that is a very bulky solution for just swapping quickly between one or two filters during a session. I have been quite surprised at the lack of options, and cost involved compared to filter wheels, which are readily available and relatively inexpensive. I actually suspect that filter drawers are geared more towards visual use (if you regularly want to switch between 3 or more filters then a wheel becomes more convenient) and therefore there is probably much less demand. Tim

Until a few nights back (see my post above), I had been a little disappointed with mine, as it didn’t seem to be making any difference to the views I was getting (mainly viewing Jupiter and Saturn). Maybe the seeing conditions on those other nights caused there to be little or no benefit from using the filter, or maybe you get more of a benefit on Mars than Jupiter (although I am sure I read that they are particularly good for Jupiter). Tim

I tried a neodymium moon and sky glow filter on Mars a couple of nights ago, when the moon was particularly bright and close by, and it seemed to improve the amount of detail visible, more so than when I’ve previously tried it on Jupiter. It seemed to cut down some of the reflection/glare around the perimeter of the planet, making the polar cap stand out more clearly, as well as a little more surface colouration. It also improved the views of the Moon by removing a bit of the glare and allowing the features to stand out (possibly the best view of the Mons Hadley area I’ve had to date). I don’t know how the improvements compare to those using a neutral density filter as mentioned above, but if you have a neodymium filter it might be worth giving it a try. Tim

How does UV marking work when you come to sell the item? Can it be removed without causing damage to any paint finishes? Tim

Just got hold of the BSW screws and they fit the finder bracket holes perfectly. So, to confirm for any future viewers of this thread, the correct size screw for a circa 2018 C8 rear finder bracket hole is: 5/32 diameter (32 TPI) British Standard Whitworth (BSW) thread Tim

Same in Nottingham. I could just about make out the GRS but no chance of Europa or the the shadow. My first confirmed sighting of the GRS though so pleased with that and thanks for the heads up.

Looking again through the various thread specifications and I think it might actually be a 5/32 BSW (Whitworth) thread. Just ordered a pack so will update once they arrive.

Thanks for the replies, and apologies for the delayed response, I didn’t get notified of the replies. I’ve read the referenced threads and the consensus across those and most threads I’ve seen to date seems to be 8-32 UNC, which is what I tried but don’t fit. Looking at the cloudy nights thread, the suggestion is that the rear holes have been drilled and tapped slightly undersized from the standard (although presumably with screws to match) and that you need to force the replacement 8-32’s in. Still not sure I like the sound of that. I’ll probably try a few different packs and types of 8-32 UNC screws and see if any are a better fit. Tim

Realise this is an old thread but didn’t want to start another for the same topic. I am having the same problem as @dweller25. I measured the existing screw as 32tpi and 0.154” (3.92mm) major diameter. I ordered some 8-32 UNC Allen head screws but they don’t fit (one turn and they bind solid). The screws I ordered have a major diameter of 0.161” (4.09mm) and therefore a fraction wider than the existing screws. The nominal major diameter for 8 UNC is 0.164”. I’m not sure if it’s just a tolerance issue or whether they are a different screw thread entirely. They aren’t M4 as that would be 0.7 pitch (about 36tpi). They also aren’t 6-32 UNC as I have some of those and the diameter is too small. I found another thread on here that suggested 8-24 UNC but that isn’t a UNC size as far as I can tell, and I’m fairly sure the existing screw is 32tpi. I also can’t see 8-32 UNF, as mentioned above, as a standard UNF size (32tpi would be a 10-32 for UNF) As far as I can tell, an 8-32UNF would be identical to an 8-32UNC anyway. I’m a reluctant to try and force the new screw in, even though it would probably just cut out a wider thread with the OTA being aluminium. Has anyone had any success finding a replacement screw for the finder bracket? Is it a case of ordering several 8-32UNC from different suppliers until you find one that fits? Would the type of screw make a difference (the ones I ordered were high tensile steel cap heads)? I can’t believe how much time I’ve spent simply trying to fit a finder bracket, or how much I’ve learned about screw threads in the process! The scope is around 3 years old so assuming it’s manufactured in China, rather than US like the older ones, if that makes a difference. Regards, Tim

Looks like SkySafari might be on offer at the moment too. £19.99 for the pro version, which is listed at $39.99 full price on their web site (unless it’s one of those permanent price reductions)

Thanks, I’ll take a look at those. Cloudy tonight though. Tim

Does anyone know of a similar tool for Jupiter? I’ve tried a few times to confirm whether I’ve glimpsed the GRS but I’m never really sure whereabouts on the surface it should be at a given observation time, and therefore whether it is what I’m seeing or not. Tim

The above was based on a quick look at my C5, which uses just screws (no nuts) to hold the front section on to the tube. Reading through the link posted earlier, it looks as though at least some OTAs use nuts on the inside as well, so the above wouldn’t work in those cases (while you could possibly use a spot of glue to retain the nuts in place for reassembly, you risk them dropping onto something fragile during disassembly). regards, Tim

I don’t know how the older OTA’s are put together, but it might be easier to remove the whole front end section with the corrector still in place (not sure of the correct term) by undoing the screws around the outside edge of the tube (check if they are plain screws, or have nuts on the inside first though). That way you don’t risk misaligning the corrector or any of the packers etc. (you will still need alignment marks on the tube and end section so that you put it back in the same alignment, but at least it’s only a matter of aligning the screws with the right holes). You might not be able to clean right to the absolute edge of the corrector this way, but it may well be good enough and the overall task will be simpler. Regards, Tim

I must admit, this is putting me off a little from buying one of these mounts, although in most other respects (variable quality from unit to unit being the other exception) it seems a great mount. I have a Celestron Mount and the Goto slewing noise was also a concern for back garden observing. On the Celestron Mount there is a Scope Setup setting called “Custom Rate 9”. It’s not obvious from the name, but this actually controls the Goto slew rate. It turns out that the Goto slews at whatever speed slew rate 9 corresponds to, and that speed can be set to match one of the slower rates. Just wondering if there is something similar in the Skywatcher Mount firmware (given they are both owned by the same company). If not, then I don’t know whether there is a forum, or a way to post feedback on the firmware download site, as it sounds like something that could easily be added to a future firmware release, if enough people want it. Regards, Tim

Playing devils advocate also. UPS postage via eBay packlink is £3.69 for a 5 to 10kg parcel. Not sure if the scope would fit within the UPS package dimensions, but the postage might not be that far off the mark and might have been discounted by the seller. I advertised free postage, even though it cost me £3.69, would free postage have made the advert suspicious too?

Many thanks to @Dr_Ju_ju for printing the part for me. The bracket fits securely onto the spotting scope in place of the original sighting tube. I’ve managed to fix a Celestron red dot finder onto it for now. It doesn’t attach quite as well to the bracket as I’d like, but that should be solvable. At least now i’ll be able to find the objects I’m hoping to observe. I’ve no idea how this scope would compare to a similar aperture and length telescope. Maybe the optics are designed more for daylight observing, although presumably the same would be true for binoculars. Anyway, it should help fill the void until I have the budget for a decent travel refractor. Tim

Hi Julian, Thankyou for offering to print this for me. 1) it is for a Swarovski scope, and as far as I can tell should fit the model that I have, although ultimately I won’t know until I try it. The whole thing is a bit of an experiment to see if I can get away with using the spotting scope as an occasional astronomy scope, as I don’t possess a refractor. I find it very difficult to locate DSO’s or specific stars in the scope due to the angled eyepiece position and fixed magnification, hence trying to add a finder. 2) I assume (unless it’s hollow) that the one piece print should result in a stronger end product. 3) Black would be my preferred colour 4) I suggested PETG as from the brief 5 minute search I did, it looked to be stronger than PLA, and a bit more durable for outdoor use, but I have no experience with either material. Are there advantages to using PLA instead? Regards, Tim

I have found a design on Thingiverse for a red dot finder bracket https://www.thingiverse.com/thing:2989735. Unfortunately I don’t have a 3D printer myself, but wondered whether there is anyone on here who might be able to print one for me? I would be happy to cover the cost of materials, postage, and time. The design is in OpenCAD format. I don’t know much about the different filament types (although I was thinking PETG as it seems quite durable) so would be interested in any recommendations. Regards, Tim

I’d like to add my thanks to FLO, Steve, and everyone else involved in putting this presentation together. Looking forward to the next one. Tim

I’ve had a similar experience with Zeiss cleaning solution. Worked great on spectacles, but left streaks on binoculars. I thought maybe it was the cloth I was using (although it was a microfibre camera lens cloth) but hearing of your experience makes me wonder whether it just doesn’t work so well with coated lenses. Quite surprised given Zeiss’s reputation in optics. Tim

The Celestron holder does look quite substantial compared to the Altair one

@johninderby I’d be interested to hear how the Celestron nexyz compares to the Altair Astro phone holder, as I’m looking to get a decent phone holder myself, and these two were on my shortlist. Regards, Tim

There were some issues when it first came out. It was incompatible with the 9.25” EdgeHD and quite a few people reported issues with it sticking or jamming. There was an updated version released around October last year that as far as I know resolved both issues. I don’t know if that is the update your specialist is referring to or whether there has been a more recent update.