markse68

Hi Josef, it’s the Royal Greenwich Observatory which is part of Royal Museums Greenwich. My astro society (Flamsteed) have links to them but no authority. I think I’ll make enquiries though as to me it’s a real shame to have such an amazing instrument performing so badly. Checking the collimation and condition of the diagonal mirror/prism wouldn’t be too costly an endeavour at the very least. Mark

I saw the comet! Well I say I saw it but what i mean is Starsense took me to where it should be- I’m convinced i was looking at the right area as there’s a pair of stars with one distinctively red (HD139920) and with averted vision I could tell there was something there below and right of it. A ghost of something- no idea what shape but definitely something 🤣 Mark

Fantastic night by the sounds of it and thanks for the report- a joy to read. I keep promising I’ll do similar with a trip out to Ashdown forest but haven’t yet- would have taken some serious polar gear last night I think! Mark

Edit- been an idiot- it is there if you type it in right And I saw it- very very faint averted vision and I wouldn't have found it without Starsense but it was there I'm sure, just below and right of the red star HD139920 (newt view) Mark

You can buy polypropylene sheet from craft shops which is similar, possibly the same stuff the commercial dew shields are made from I think. It’s cheap and easily cut with a stanley knife. I used the 50mm wide extra strong self adhesive velcro along the edge and it’s a b*****d to unfix but does the job well Mark

Well- that was a let down! I had seen Mars through it back in November when it was much lower at 8-9pm viewing time and had seen some dark features but not with any sharpness and I had put it down to atmospheric disturbance and had hoped this time round with it overhead (although smaller) that the image would be sharper. It was terrible I get a far far superior image from my little 6" f5 Tal reflector! I confirmed this later on. It's such a shame but I think the scope is in dire need of some serious attention. I suspect it is a long way off collimation as they first used a 50mm ep for ~170x and with Mars centre of view it had terrible chromatic smearing- not typical chromatic aberration (its an achromat) but a linear smear. The optics haven't been cleaned in a very long time but that's not an easy job given the cell weighs 100Kg and isn't very accessible. It really needs the Es Reid touch to bring it back to its potential. It's a lovely old thing and quite a feat of Victorian engineering and I'm sure it could do better! Mark

I didn’t get out till late unfortunately but the seeing was excellent from here in London too. Mars was beautifully clear- some mottling apparent in the lighter region and it looked like a proper world rather than a glowing ball. Having read through posts here and lazy to look through my lists, Steve’s 32 and 52 Ori were lovely splits at 250x with my Tal barlowed 6mm CZJ ortho. Wasat was a new one too and very nice with its tiny faint pinprick b star. Unfortunately I didn’t have Steve’s success on Sirius- it was a bit too fiery and I forgot to check the Trapezium. Thin high clouds rolled in and it was very cold so only about an hour or so but very enjoyable. Forecast is clear tonight too which is super exciting as I’m off to view mars through a 28” f12 refractor 😀🤞 Mark

Exciting! off out now for a look 🤞 Mark

I can see Saturn has rings and just about make out Jupiter has banding at 14x with mine

Thanks Michael 👍 Mark

There are several of the #22-3030 Telephoto Camera Mounts on ebay but they are all in the US so would incur import VAT but ebay usually handle that and would likely still be cheaper than a good quality phone mount. You’d still need a T-mount adapter for your camera but if you don’t mind waiting a while they can be had quite cheaply direct from China via ebay again. Mark

I think it could be real- there are several images on Astrobin which show a similar bubble around them- could be from their combined stellar winds blowing the nebulosity they’re in outward or perhaps the collapsed cloud they formed from? I heard that the nebulosity is only meant to be something they’re passing through but how can they tell that? Nice image anyway Mark

Anyone know if a 1.25” Lacerta wedge will reach focus with a Tal-100RS? Can’t find spec on optical path length but it looks quite large Mark

agree about the anodising- you need to apply enough pressure that the anodising invariably breaks down- the ones with steel inserts are a much better idea. But surely you’re not against friction drives in principal Ollie? 🤔 Mark

Yea best to use a 4 jaw chuck and dial gauge off a shaft that’s a good fit in the existing bore- not a 3 jaw or you’re almost guaranteed eccentricity Mark

Amazing that someone with such a dangerous profession can live to 94! What a legend!

There’s an ebay seller called Starvue who has caps in all sorts of sizes for binoculars/spotting scopes Mark

I get it when looking at Mars- at first I see very little but then the detail gels over time. Could it be that the details are more colour based in Ha rather than brightness in white light? Using different cells/perception in the eye? Mark

How did you measure the position of the mirror old vs new? Is it possible that even though the new cell is mounted further inside the tube that the actual mirror is further back due to the thickness of the old cell? You should have a fair bit of mirror height adjustment on the collimation screws- from the photos it looks about 10mm haha! You should be able to just reposition the mirror closer to the end of collimation adjustment screws to bring the focal plane further out at the focuser. Mark

That’s really great Geof! Mark

I don't know that specific focuser but on my Moonlite there's a block of PTFE in between the screws and the focuser spindle and on my Feathertouch it's a block of steel I think that acts like a lever against the spindle to apply pressure/lock it. My guess is yous would have something similar that has fallen out- hopefully it's still there and you can sort it out on disassembly 🤞 Mark

it must be missing a thrust plate inside or maybe it came loose and is rattling around in there? Mark

Are there not screws for adjusting the tension on the spindle against the draw tube? There are usually near the locking screw Mark

That's really great Mart! Mark

I hadn't and thank you Geof- yes Martin's map is very nice and useful Mark