Waldemar

Reflectors do not have chromatic aberration normally, so your problem is the Barlow. The used lenses inside the Barlow may be plastic like the outside...

I totally agree... this was just meant to be an example. Many ways to DIY On the other hand the turnover on this kind of stuff is low, so the prices need to be high in order to get out of initial costs.

https://www.bing.com/images/search?view=detailV2&id=1E502F26DB74498AD81488DF53D9F9FC3E22F190&thid=OIP.5sZqFlIJJVT6PjL1RVSrSQHaFL&mediaurl=http%3A%2F%2Fensoptical.co.uk%2Fimage%2Fcache%2Fdata%2Fproduct-3179%2Fcounter-weight-a2-1000x700.jpg&exph=700&expw=1000&q=balance+system+for+etx+90&selectedindex=42&ajaxhist=0&vt=0&eim=0,1,3,4,6,8,10

Balancing is very critical, not only for imaging, also for visual, albeit less. So... to prevent your mount from giving up on you, please pay attention to the balance!!

So you mean the clutch system... If the balance is near perfect the chance of a slipping clutch is minimal, but if a rubber ring or any other material will give you more grip, that should be ok. Edit: Don't forget the slippage serves a purpose: it protects the motors against burning because of imbalance

Just change the knobs one by one. In that way you won't ruin the collimation a lot

Maybe you can attach a picture, to be sure? If you mean the dovetail on the scope and the dovetail clamp on the mount, then no, there should NOT be any rubber things in between. The clamp should grab the dovetail in a solid way, without any possible movement.

No need to do that... the filterwheel should attach to the camera without anything in between, but maybe an adapter... as close to the camera as possible

In many cases the diagonal has screw-off 2" connectors, as well as the Quark does probably, too. Try to unscrew with sensible force...

And of course you got that 3D printer, Gina... that works too, I guess 🙂

I've got 42, 48, 52 and 68 mm metal spacers from https://www.teleskop-express.de/shop/advanced_search_result.php?XTCsid=of0ltqsf8cvoeksi4bu5p54k87&keywords=abstimm+ring&suchdas=OK, I also made some myself from copper sheet in several thicknesses. All depends on what size and thickness you are looking for.

Because manufacturers are not interested in making equipment that lasts a life time... They need turn-over. edit: Btw, the best grease to use is one that is PTFE (Teflon) based like SuperLube. Don't use too much, packing bearings is a no-go, use it sparingly. Mount bearings do not have heavy loads like car wheel bearings.

Hi Vin, Since this is a guide scope, why would you want such an expensive focuser on it? The total cost will be several times the cost of the Evoguide50ED... and once focused it is not needed anymore... Here: http://starlightinstruments.com/store/index.php?route=product/category&path=38 you can try to find an adapter to attach a Feathertouch focuser to your Evoguide

This USB-ethernet converter solved all problems I had with USB 2 and 3 connections: https://www.silextechnology.com/connectivity-solutions/device-connectivity/ds-600 It can handle 4 USB2 plus 4 USB3 connections. The ethernet cable can be max 100 meters long.

Maybe this can be of any help: Cleaning solution.docx

well 'nothing to worry' is not exactly right... The jamming may damage the motor, and with the belt upgrade the worm & wheel are still i use, so you will have to readjust the spacing to solve the problem.

Sounds like the worm & wheel were jammed... Sometimes that happens when the worm-wheel is not perfectly round and/or too tightly adjusted.

That Baader astrozap front filter will be okay on it's own. Any other filter in your filterwheel is of no use. Solar H-alpha filters (etalons) are totally different from the 'normal' H-alpha filters used for NB imaging. Heat will be of no problem in either mentioned scope or setup with the Baader foil.

Graet choice! I am using SX for years and never had any issue. Great material and simple to install. works with any software I know and very versatile because of the available adapters. I got the giant wheel 9 x 2"and the 5 x 2" wheel

That goes for the RA or DEC axes to get rid of backlash. It does not solve the problem at hand.

lay two pieces of wood, or T-profile, or what ever material you can think of of about a meter long on the table and lay your telescope on them in such way that it can roll on the material. You should be able to lay it still in any position. If it moves to a certain position you should change the position of whatever causes the imbalance or put some counterweight on the top side, for the heavy side will be lowest.

If you would look through a microscope to any machined metal surface, you would see that the material is not as smooth as it feels. The surface is in fact rough in several degrees, which restricts a real smooth movement. PTFE based greases and oils like SuperLube consist of different sizes of PTFE particles which fill up these 'rough' areas, depending on the need. In that way those type of lubricants really smoothen any movement. On top of that the temperature range is like -40-+300 ° C, so basically suitable for all circumstances. In fact you could say this type of lubricant has a negative resistance coefficient, meaning the more pressure, the better it works. Personally I lubricate everything with SuperLube for years and years already. From my bicycle to my mount and everything in between.

Cleaning and regreasing before upgrading is always te way to go, I would say... Be very careful with the optics, though! Use PTFE based SuperLube for everything that moves, but clean well before applying. A little goes a long way, do not 'pack' the bearings. Brake cleaner works very well to clean the worm and wheel. Do not open closed bearings, better replace them. have fun and succes!

There are three ways to balance a scope: DEC, RA and radial. All three are important to obtain good balance. RA and DEC are obvious, radial is along the telescope's axes. Any finderscope, filterwheel or motorized focusser will disturb that balance and needs compensation. A nice way to do that is to lay the telescope perpendiculair on two upside-down T-profiles and see which direction it roles. Compensate for that by replacing or adding weight on the opposite side, untill the scope stops rolling in whatever position it is on the T-profiles. The only place that needs no compensation is when the weight (like a camera on a Newt, or a filterwheel on a frac) is in the direction of the CW bar.