yuklop

Hi everyone, I sometimes wonder if I’m not going a bit barmy! I have a lx200 12” on a wedge. I understand balance is important and I can achieve perfect balance in dec. There are many guides, and it’s a straight forward matter to sort out. Most of the guides then say at the horizontal position release the RA clutch and see how the arms want to move - then balance. No problems so far. The bit I haven’t seen explained is, as soon as the forks are rotated about RA the balance is lost. Whichever arm is high wants to drop. It very much wants to return to the level position. I can fix this by adding weight to whichever arm is low. But it would require a different amount of weight for each RA position. Is this normal behaviour? Is there a sensible fix since it must be best that the scope to be balanced however it is pointing. I can only imagine this is because there is a load of weight at the top of the forks, I.e motor assembly on one side and balance on the other. But if that’s the case why isn’t it mentioned in the guides on balancing!?

Yes, it does. The tricky bit is that I cannot be balanced for all RA positions. The correct balance for forks level is not correct for forks not level. And trickier still the extra weight to balance must go on the low arm (which of course changes depending on whether it is pointing east or west) I think it needs balancing for whatever RA position it is in for imaging, which is a pest. I’m wondering if that is usual or if I have somehow done something odd!

Hi everyone, I sometimes wonder if I’m not going a bit barmy! I have a lx200 12” on a wedge. I understand balance is important and I can achieve perfect balance in dec. There are many guides, and it’s a straight forward matter to sort out. Most of the guides then say at the horizontal position release the RA clutch and see how the arms want to move - then balance. No problems so far. The bit I haven’t seen explained is, as soon as the forks are rotated about RA the balance is lost. Whichever arm is high wants to drop. It very much wants to return to the level position. I can fix this by adding weight to whichever arm is low. But it would require a different amount of weight for each RA position. Is this normal behaviour? Is there a sensible fix since it must be best that the scope to be balanced however it is pointing. I can only imagine this is because there is a load of weight at the top of the forks, I.e motor assembly on one side and balance on the other. But if that’s the case why isn’t it mentioned in the guides on balancing!?

Thanks for the comments. I had a colleague who had a car crash into his garage knocking this scope for 6. It got a bit dented and insurance wrote it off. He got himself a new 14'' ACF with the proceeds, lucky chap, and I got this one for a good price. This would be risky, but I got to try the scope and check the optics out before I bought it. The dings and dents could all be knocked out!

Hi Everyone, This post is about restoring and rebuilding a 12'' LX200 classic. I did a load of research and pulled ideas from various parts of the internet and I want to post it all in one place in case others find it useful. A summary of the mods I did (a more detailed section on each mod follows including how hard it is, how effective, how expensive, and where I got the bits). The start point was this LX200, which was optically good, but a bit battered around the edges (had been an insurance write off when I purchased it). It also had a dec drive with huge backlash (>99!) and it refused to slew further round than due east. Summary 1. Stock focusser upgrade 2. OTA deflocking and internal painting 3. OTA and forks painting 4. Serviced the finder scope 5. Replaced all electronics with Onstep 6. Replaced dec and RA bearings 7. polished the brass bubble level! 1. Focusser Upgrade Guide: http://www.skymtn.com/mapug-astronomy/MAPUG/ImgShift.htm Cost is just a few pounds, it is very easy and a very effective modification. In fact, if I were only to ever do one mod to an LX200 it would be this one. You need: 2 x Needle roller cage bearings: https://simplybearings.co.uk/shop/p110004/NTA815-Needle-Roller-Cage-Only-0.50x0.9375x0.0781-inch/product_info.html 1 x Thrust washer: https://simplybearings.co.uk/shop/p110209/TRA815-Needle-Roller-Thrust-Washer-0.5x0.9375x0.0312-inch/product_info.html 2. OTA deflocking and internal painting Here is how to take it all apart: http://www.lx200classic.com/files/Gutting your LX200 OTA.pdf My OTA had awful flocking all over the inside. Put on with tape that was both near impossible to remove and flaking off at the same time. Cost is low, but it is time consuming and tricky, especially since you need to remove the primary mirror before attempting this. It should be fairly effective though as I won't have bits of old flocking hanging off inside the tube. You need: IPA to help remove adhesive. Elbow grease. Then some chalk board paint into which I mixed a load of carbon black for an extra absorbent and rough non-reflective surface. Then paint that on. 3. OTA and forks painting No guide required for painting. You do need to take it all to bits though. A really good guide for that an the reassembly: http://www.skymtn.com/mapug-astronomy/ragreiner/decfixmajor.html I painted mine white with black forks. Image at the end! I will say my mount had lots of small areas of corrosion that needed rubbing off first. 4. Serviced finderscope Mine is a skywatcher 9x50 right angle finder. Very easy to take apart. Nice clean with baffles and optical wonder and it is as good as new. Well worth doing. 5. Replaced all electronics and motors with Onstep I was facing tuning the LX200 drives like this: http://www.skymtn.com/mapug-astronomy/ragreiner/decdriveadjust.html or http://www.lx200classic.com/files/Bruce_Johnston_LX200_Drive_Repairs.pdf Didn't fancy it. So I thought I'd rid myself of the old drives and all the old 1990's electronics at the same time and replace it all with Onstep. Now its done it was definitely the right choice. https://onstep.groups.io/g/main I cannot speak highly enough of Howard, Khalid, George and Drew and all the other great people working and helping to allow folks like me to restore an old telescope with Onstep. I'll post a message to the onstep boards on all the details, but essentially I now have a stepper motor driven mount, 2 electric focussers all controlled over WiFi from my phone or tablet. Cost is very low for such a major mod (<£100 in my case). I will likely recover all the money when I sell the old handset and electronics. You will need to be a bit handy with a soldering iron and computer science but the instructions are good and the help available is awesome. 6. Replaced Dec and RA bearings RA: https://www.cloudynights.com/topic/507157-ra-bearing-replacement-and-accessory-cable-management-modifications-for-a-meade-lx-200-gps/ You need one of these:https://www.ebay.co.uk/itm/113994912099 BEARING SIZE:6013 2RS 65MM X 100MM X 18MM and one of these: https://www.ebay.co.uk/itm/360617561146 Dec: http://www.skymtn.com/mapug-astronomy/ragreiner/decfixmajor.html You need: 2 x roller bearings: https://simplybearings.co.uk/shop/p92349/BA1616ZOH-Imperial-Needle-Roller-Bearing-1x1-1/4x1-inch/product_info.html and a couple of thrust washers. I got mine from ebay: https://www.ebay.co.uk/itm/KOYO-TRA1625-Imperial-Thrust-Washer-1-x-1-9-16-x-1-32/123720798055?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 And to have the mount dec holes accurately bored. This cost me £30 by a bloke with an industrial milling machine my wife found on facebook. My experience was that all the local engineering companies didn't want to know. It is the one job in this whole build I could not do myself. I do own a drill press, but it was not worth messing up the centering. 7. Polished the brass bubble level. As standard it is painted black. Rub that paint of and it is made from brass. Lovely. Oh, I swapped the old handle on the back for a chunky kitchen drawer handle. Another great little mod! The final result is below. Hopefully may more years of action for this this excellent old LX200 classic with its new lease of life.

Hi Michael, Thanks for the link. I think the play on mine is on a different cog, but I suspect the principle of the fix could be the same. I will have a good look and see what I can do. Regarding the RA drive. Does the picture look right? The is a picture of the drive as it is installed before I removed it. What does that adjustment screw below the spring actually do? I can't see its doing much in this setup, other than being a hard stop if the worm is pushed too far down. Thanks, Dan

Hi Michael, Thank you. I know something is pretty sub-optimal with it. It looked quite odd. Where the spring is between the hinge there is a recessed dip that look like it should seat the spring. In my case the spring was mounted over the screw. I wondered if that was normal too. The screw was so lagged in a thick grey grease that I could barely see it. I would expect that was unusual too. But actually the most concerning thing is the play in the little cog on the motor shaft. This may also be hardest to repair. Dan

Hi All, I have an lx200 classic and the drives are not behaving well. The dec drive has a backlash compensation set to the max (99) and it still isn’t enough and the scope is a picky about slewing to northern areas of the sky, it essentially gets stuck with the drives turning and the scope not moving. I have taken it apart and have the drives out. I can see two options. Service the drives, there is tons of help online for this, or just keep the worm and main gear and convert it to a onstep system. Both pretty cost effective. Do folks here have an idea of the relative pointing and tracking accuracy of the onstep system vs a standard lx200 fork mount drive system? Remounting on a GEM isn’t going to happen as it is very expensive and also I like the fork mount!! Many Thanks, Dan

I have an unbranded set of LRGB filters (perhaps old QHY filters, but this is far from certain). If the brand of filter isn't known, then the true transmission spectra also isn't known. So I measured them with some interesting results. Unbranded LRGB Now compare this with a Baader Blue filter: The Baader filter has much better IR suppression. It is B + IR Cut, compared to the unbranded filters which have high transmission in the IR for each of the RGB lines. The grey line in the LRGB graph is the L filter. This filter is a decent UV, IR cut. So I think if I use the colour filters with the L filter always in the optical path I could reproduce the effective IR cut of the more expensive branded filters. I also measured all my other filters and every one was interesting. You can get your filters professionally measured here: https://www.gerdneumann.net/english/service/spektrale-vermessung-ihrer-filter-spectral-scan-of-your-filters.html But they charge a frankly staggering €25 per filter! I can also measure your filters for you. PM and we can discuss, it certainly won't be €25 per filter! Dan

Hmm, thanks for the reply. I think it is actually a star Gaia DR2 ... a magnitude 13 star thats crept into shot masquerading as one of Uranus moons. Damn. Still means I didn't capture all 5 of the possible moons. I will try again next time. :)

Hi Folks, I had a go at imaging Uranus and its moons a few weeks back. I just got round to processing the data. Came out ok, if lacking any real detail in the planet. My puzzle is, when I came to figure out which moon is which with Stellarium, I found 4 of the moons match what I recorded, but one does not. I can easily imagine Miranda being lost in the planets glare, but then what is the bright dot directly above the planet. I can't see any stars in the area and I checked the magnitude isn't limited on the planetarium app. The video was shot on 09/12/19 at around 21:00. Kit was: LX200 classic, 2x focal extender, ASI224MC. Any help greatly appreciated. Thanks. Dan

Hi All, I'm considering what software to use in an astrophotography workflow. So many options from free to very expensive. I made this little diagram to try and decide. I don't need no cost, but low cost is nice! Seems like everyone on Astrobin uses PixInsight. Of course there are much more comprehensive lists out there such as: Here I suppose this question is asked fairly often. Do you think the diagram is about right in terms of functionality? I expect I'll start with Stellarium, APT, Deep Sky Stacker and Startools as a low cost option. I guess this will work well, although I know Deep Sky Stacker and its a little long in the tooth now, so perhaps an upgrade to APP or PixInsight will happen soon enough. Any other cheaper stacking tools you would recommend? Many Thanks, Dan