powerlord

aye, there used to be an excuse as you say - where would you learn to do better - but now nearly everything is a few clicks away. there's no excuse really. And yeh mechanics who don't use torque wrenches and swear they get it right by feel (though you can bet they have never actually put it to the test) are a bugbear of mine for sure - from wheel bots nearly welded on, to stretched head bolts, etc. arg...

hmm, ok still a problem then. Oh well.

maybe something in that - I had a plumber doing a new bathroom a few years ago.. he was struggling to screw the shower cabinet together. I looked closed and he was using a flat head driver - the screw was a posidrive. I said to him - er.. what are you doing ? "this is better - the philips one slips all the time" I explained to him what posidrive was and yeh, philips will slip, cause its not a philips screw head... which was apparently completely new information to him.. he of course, continued to use his flat head driver to knacker all the screws as soon as I left the room. But still, if you know nowt, don't tough it surely ? I mean, if you are the sort of person that doesn't know metric from imperial, posidrive from philips, surely you'd think twice before hacking into 1500 quid worth of mount?? But apparently not. sigh.

offt. ok that's an issue. what resolution tv, and size of tv is that based on ? For example at 2m, a 4k ipad pixel size is going to be massively smaller than say, a 1080p 42" tv at 2 meters. is there a combination that would work I wonder ?

yeh focusing the scope and guidescope would be tricky for sure. with an OTA. But we are trying to test guiding here, not telescopes. Just use a camera ? a DSLR and regular lens will have no issues focusing on tv ?

<rant> A bit of a rant... I've bought quite a bit of second hand equipment in the last year - from folk in here, or folk on astromart, and the number of times I find the following defies belief... I really can't understand a person who purchases something, perhaps costing over 1000 pounds, and then can't be bothered buying a 5 quid set of allen keys, or a proper circlip/needle nose pliers.. or just goes in there and screws things up without a clue what they are doing. It seems almost the default ? As An example, I purchases a second hand EQ6 pro a few weeks back. From astromart. I went to see it and the person selling it was selling it on behalf of a friend who had passed away for the family. He himself had lots of fancy mounts, his own observatory, etc. So I trusted his judgement when he said the mount was all working and in good order. On getting it home, on the first night I noticed the worm was jumping.. and then once that was adjusted, some other issues, and finally over the weekend, I took the time to totally dissassemble it and fit a rowan belt mod that was sold with it, boxed. Here's some of the things I found... and remember, this is a 1200 quid mount... 1. every one of the 4 bearing covers was scaped and botched where it had been taken off/fitted with who knows what rather than a proper circlip type tool. They were also tightened massively tighter than they should be. 2. several of the grub screws were worn where a metric allen key has been used instead of the proper sized imperial one (hint.. if allen key is a bit loose.. it's the wrong size. stop!) 3. the lower ALT adjustment bolt was really really stiff. It was hardly possible to adjust, and hard to remove. On removing I notice the threading on the ali is all burred and knackered... 4. with the ALT bolts out. the mount will not move at all in the ALT pivot - it's been bolted so tight it can't even move ! No wonder they have been having to force the bolts in, scoring the tilt plate in an attempt to move it. hint... if it's not moving.. ask yourself why.. stop trying. 5. To dissassemble the ALT axis, I need to remove the EQ6 plastic badge cover and degree one on the other side... yup - you've guessed it, both glue on with tons of epoxy - could not be removed without chipping them off in bits. 6. the bolts of course are rock solid tight, once removed I see the grub screws on the adjuster plate also massively tight. It all had to be taken apart, cleaned, regreased and put together again with an appropriate tension, so that, guuess what.. the axis can actually work as an axis and rotate!. Of course I now don't have any covers but if I did, I wouldn't be glueing them on with epoxy I could never remove again!!!! Needless to say, this was all quite annoying , and I expected better from an experienced felllow astrophotographer, but it is not the exception - I've had vixen plates where a metric bolt was been forced into an imperial hole, gears adjusted so tightly they hardly move. etc etc. </rant>

I'm wondering if anyone has every done this, and if not, if anyone wants to, and even if they don't it's interesting to think it through...(to be clear I AM NOT GOING TO DO THIS). Seems to me testing, tuning guiding is tricky in that you can only do it outside with clear sky, etc - and that's when you want to be imaging. And if, say you want to have a business of tuning mounts, you want a reliable way of doing it all day every day ? How about this: - shoot some wideish field 4k60 footage of east or west (doesn't need to be, just an idea) on a good clear night. fov should be chosen to ensure stars resolve to a decent FWHM (2?). Note day, time. It should be at an AZ that is equivalent to where you could put a tv/monitor on your wall 3 feet or so from the mount.. In house, mark dot on ceiling precising north of a position on floor the correct distance back to reasonably accurately represent polaris (this all works best if your room is orientated N/S) Position tripod so that polaris centred. and set mount to date and time of video footage. Mount tv to wall in east or west in AZ location matching the footage. calculate 'FL' of guidescope by plate solving, pointing it at tv (i.e. won't be actual FL, but will be whatever it works out to. Now, setup mount, goto or adjust direction to point main scope at tv, and plate solve. Now should be tracking. Set up/calibrate PHD2. Start guiding. It should now be guiding based on the tv. It's not that important to be super accurate here I'd imagine as the point that we are trying to test is how good the guiding can be, not how good the PA is, etc. The benefit it at least seems to me, is once you do all the above once, and record positions on floor, ceiling, FL for guidescope, tv/monitor wall position.. you can now set it up again any time very quickly. Thoughts? Or is there a simpler way ? home planitarium ?

smooth knobs easier to CAD. Because that looks to me like a solidworks CAD render. Not a real product at this stage imho.

oof. a sense you would not be happy ? I'm all for getting it better, if it's within my capabilites. What are you thinking ?

Tada ! other than the very top left - pixel peep away Mr @vlaiv !! Me thinks I can live with that. top left could be my distance to baader mk3 still a bit out. but considering the secondary had a chunk out of it, that looks pretty good to me! Also I appear so far at least, to have sorted the initial problems out somehow, possibly connected with the fact the thing has been taken apart and put together a bunch of times by now. what was the big issue from last time you ask ? that'll be me thinking that the mirror was loose on the 3 clamps, and tightening them all... not realising that was the last thing you do. hence optics were pinched to bits. So.. after the last effort I'd given up and ordered a new SW 150p-DS, but I've emailed them to say cancel, because tbh it seems to be working fine now. agreed ?

@admin could u move this to imaging please? Posted here by accident and only just realised.

Been doing this a year now and never done the big boy for some reason. 30 mins in, g and b. 25 mind in ha. Shot at 400mm (asiair 80ed and ff). Thought I'd posted this earlier but isn't there.. So trying again.

You'll also want probably a bt remote, and deepskycamera if on android. Focus is the hardest bit, but then for wide field they can be very good. They have mentally small pixels - e. G. The s21 has 108mp camera!! But pixels are 0.8um. Though it can hw bin. But since they tend to stack in hardware for long exposures, you can get very nice shots with them without darks and bias.

they are all basically the same - a springy clamp, and a thread to attach to the tripod. it's a generic enough thing that you just need to buy the cheapest. they are only about 2 quid.

its the baader mk3. I've got it precisely (i think !) 55mm from sensor. I did collimate it myself, so it's not collimation I don't think

hi chaps, contrary to forecast, it's clear at least for the moment. so live now, I'm capturing some subs from IC1805. here's one stetched in siril. the good news is stars seem circular in the middle. and bottom left and right look ok too. top not so good. bottom left.. weird. top right.. weirder. but could be unrelated to damage? could this just be tilt ? it's up just now, so any ideas folk have, I'll try them if I can. scope will still be cooling down, as this was an unexpected session, so only been out about 30 mins at this point. stu

just an update, that it's now back together and collimated. looking at terestrial stuff, it looks good. no darker bits. pointing at sky it looks flat. So.. just have to wait and try when clear I reckon.. there's hope yet. stu

thanks, appreciated. It does sound like it might be about same as one I have though, but for different reasons. It's not something I can swap back and forward really either as I understand it - one needs somehow removing from mount, and the other glued on ? I think I'll leave it, but thanks for the offer. I'll see what the current OTA works like next clear night, then go from their. I'm not wonderful at collimation - every tutorial is massively longer than it needs to be imho (yes.. including astrobaby's) and one contradicts the next one.. But will give that another go and get it close as I can before hand and see what I get. again, much appreciate the offer. stu

Thanks Vlaiv, but no it's this one: https://www.teleskop-express.de/shop/product_info.php/info/p1667_TS-Optics-Newtonian-Secondary-Mirror-elliptical---D-63-mm-minor-axis.html With vat, shipping and import fees it'd be 1/2 the price of a new scope, and I've got that mark on the primary still. I think A new OTA makes more sense frankly. @Starflyer - a very generous offer if you have something, but honestly don't put yourself out - it's my own stupid fault, and I'm not short of a few bob - it's more the hassle and feeling like an idiot for it happening, than the money to put it right. As I say above, I feel IF I bought a new secondary, there's the cost, the hassle of shipping, the fitting it to the support, etc.. and then after all that I still have a primary that is damaged, AND an OTA that had a weird problem in the first place again.. seems to me, maybe just getting a SW 150-DS is a better plan. If that all works, I'll probably let someone on here have the old damaged, but sort of working one for the price of postage for someone who wants it.

Well, stuck some matt black paint over broken bit of secondary. Will see.. Someone mentioned replacement secondaries cheap? But looking here it's 110 with vat. https://www.orionoptics.co.uk/product-category/optics/elliptical-flats/ 89x63 is closest. I mean, cheaper from aliexpress but then you don't know what yer getting. So I feel if paint doesn't work, best binning it all and getting a new one, or the sw 150p-ds.

i was thinking that myself - a bit of black paint on over the cracked off bit. though that would mean taking it apart again - one for another day.

Will see. at this point it is all I can do to avoid smashing it all to bits with a hammer. Maybe after a few days with some perspective I'll talk to FLO about a replacement secondary. stu

All because last time I took a spider off my 200p, i found the arms were bigger than the scope. so in order to get it out, you had to bend (not bend bend, just springy bend) the spider arms to get it out - so I though this was the same - undid first 2 at same time, undid second 2 at same time - and blam! sigh. I am glad it is friday.

i was talking about the cracked secondary Vlaiv. Yes, the mark on the primary is gonna effect things, but it's no worse that dust/dirt on there. I hear you about diffraction - we'll see what it's like - but it's a cheap scope - I'm not burning loads of my time on it frankly.

so.. maybe... just maybe I'm ok. as I'm using an asi1600/533. the primary jas been 'scuffed' but otherwise ok. all collimated now and it looks like the cracked but is pretty much completely out of fov of asi1600. So.. it's shot using full frame cameras with it for sure, but I think ok otherwise. sheesh... and wednesday I bought at used mobile phone from a bloke on gumtree that turned out to have a touchscreen that didn't work ("oh I've just applied a software update -see - it's now rebooting and all yours"... on getting home and charging I find out its duff and he won't give me my 155 quid back). then this. arg