First Use of the Celestron Focuser on my SCT

[@larrywoolard4160]

After over a year of adjusting my Celestron focus motor on the C14 and not being able to tighten the adapter plate completely without the motor locking up and screws working loose I tried this simple fix: Place the OTA pointing down, remove manual focus knob, install the adapter plate with screws still loose, then use a centering bushing to EXACTLY center the brass shaft of the focus assembly with the inside diameter of the adapter plate. You can now tighten the three screws while making sure the centering bushing remains free to turn. This will exactly center the focus shaft with the three mounting threads of the adapter plate used to mount the motor. In my case the C14 has a tapered brass focus shaft (where the knob would mount) so the bushing inside diameter should be just a slip fit as measured where the focus shaft comes through the adapter plate. It is important that this bushing bore and outside diameter be concentric and that both be a slip fit. This is actually an assembly tool Celestron should include with the electronic focus motor. Since I made this change my motor works perfectly!

[@Aero19612]

Glad you got it working reliably. Celestron didn't do its best design work for their focus motor. They need a flex connection to accommodate misalignment or a precision assembly tool like you used. Mine worked all through last galaxy season with no issues (longer screws + Loctite). Huge relief. About to enter a new galaxy season, so fingers are crossed. Thank you for sharing your mounting approach, Larry!

[@larrywoolard4160]

@@Aero19612 If you need an assembly bushing I will gladly make make one for your 9.25. No charge since you have helped me so much with your fine videos.

[@Aero19612]

That's a very nice offer, Larry! I think the root of my problem is a little different from yours. In my case, one of the three threaded holes in the SCT is almost stripped (at least the upper threads) so when I screw my adapter plate into that hole, the screw works itself loose. So far, the longer screws and Loctite are keeping everything solid. Famous last words, but it's working for now. Thanks again!

[@colmbrazel]

Thanks for video. I wonder if loading other star catalogues into Stellarium might show that missing star? I'm always intrigued by the Concept of Critical Focus Zone say of +or- one pixel and atmospheric distortion maybe up to 3 pixels due to prevailing temp and conditions and backlash and how you separate one from the other. Very interesting Great effort there thanks.

[@Aero19612]

Hey Colm, I need to check the latest release of the Stellarium catalog to see if they have this star now. It’s awfully bright to have been left out. I’ve often thought that “focus” is a mythical place we imagine but can never visit. As with most of astrophotography, the perfect is the enemy of the good so we just do what we can get away with. Thanks for watching!

[@RaysAstrophotography]

Nice setup James! Particularly the planning for OAG!

[@Aero19612]

Thanks, Ray. Do you use your C14 with the OAG and without the focal reducer? Do you have difficulties finding guide stars?

[@RaysAstrophotography]

@@Aero19612 OAG I use only on the refractor. I don't want to use on C14. Very difficult to get guide stars. Too much of a trouble

[@DJRonnieG]

Been using Esatto 2" on my C8 but I needed to switch to attaching a Sesto Senso II. Kinda fudged the mirror movement armature during calibration when I had it overshoot the mark. Nice power and hardware box! I just run a CAT-5E outside and I keep a laptop on a plastic bin with the electronics and power supplies. I ought to share pics in a video soon.

[@Aero19612]

Thanks for watching, Ronnie! I'd like to see your setup. Let me know when you post it.

[@drfritz142]

Thanks - I really enjoy your channel and the way you approach the testing / setting up of your equipment with taking test measurements, doing a table in Excel, fitting, thinking about it... right down my alley. So thanks for the good quality stuff here! I have a question regarding Stellarium - towards the end of your video you show the fields of view of your main scope and what appears to be the guide scope in stellarium. Plus two more centered circles. This is neat. How did you do it? Thanks and clear skies!

[@Aero19612]

Thanks for watching! The two circles and rectangular box out side of my imaging sensor boundary represent the view through my off-axis guider. The "oculars" plugin for Stellarium allows you to see what your OAG guide camera sees which is extremely valuable when planning an imaging session.

[@drfritz142]

@@Aero19612 always. You make excellent videos. I’ll have to check that out. I think I have the oculars plugin but maybe not... I just fell in love again with Stellarium after I connected it with Ascom.

[@Nottsboy24]

Interesting upload 👌 loads of wires but i can see your well organised...I have the Celestron Nexstar Evolution 9.25 which is full of new innovation. I can't go through it all but it does not require a auto guider, how it works is once set up and aligned using the SkyPortal App software installed on a Android or iPhone device you can then align to ten more calibration stars...the more stars you align to the more accurate the tracking eliminating the need for a auto guider. The mount generates it's own wifi and also has a 10 hour lithium ion battery installed. You can also polar align to any star or planet which cuts out polar aligning to the north star 🔭

[@Aero19612]

Agree--this wiring arrangement will get cleaned up. I'm impressed if you don't have to have auto guiding. I can see how you can have a very precise pointing model, but how does that compensate for minute back and forth due to mechanical gear variations? I'll read up on it. Thanks for watching!

[@Nottsboy24]

@@Aero19612 no backlash due to the new worm gears plus the 10 calibration stars prevents that happening....also no Meridian Flip as my mount is alt/az mounted on a HD Pro Wedge

[@scalemodelenthusiast1633]

Thank you for this! I have been shooting night scapes of the milky way with my DSLR for many years. This week I took the plunge and purchased my first telescope (9.25 SCT NEXSTAR Evolution). I also purchased the Celestron auto focus motor and was concerned about the functionality. I am still waiting for B&H to get it shipped but in the mean time I’m trying to get as much info about it as possible. As a newbie can you offer any advise on how I should go about dialing this in for my rig? Thank you

[@Aero19612]

Congratulations on your new scope! If you're still using your DSLR, you won't need to worry about setting filter offsets (as in my video). Some camera-control software have autofocus routines built in (e.g., NINA and SGP) and some do not (BYEOS and APT). The thing to watch out for is the attachment to the scope. My scope mounting plate has a damaged thread so the little screw doesn't engage well. When you mount your focuser, see if you can identify the size/thread of the screws you will re-use just in case you have to buy some slightly longer ones. Let me know if other questions come up.

[@BrokenPik]

So the backlash compensation is 20 steps ( IN or OUT) in NINA ... there are 2 option. same with SGP you have a choice of In or Out only not both .... so 25 steps with 20 steps backlash out? i just got mine and its a mess . i thin the backlash looks more like 100 steps :-( before it starts to go the other way...

[@Aero19612]

Hey, Mitch You just got the Celestron focuser and got a backlash of 100 steps? Seems like a lot. Did you use the method I demonstrate in the video? The NINA "overshoot" method is the same as SGP. You can also mimic this in APT (see 20:45 in kzbin.info/www/bejne/qIXClKqhi7KbpNE). In these cases, the focuser gears are always in contact for one direction (say, inward). When you command a move in the opposite direction, the focuser moves the commanded amount + the actual backlash + the overshoot, then moves back inward by the actual backlash + the overshoot, leaving you in contact for inward motion but now farther out by the commanded move. APT has another method (as does NINA) where you specific the inward and outward backlash, but the other method is more reliable. Hope that helps!

[@justus8420]

Really nice Rig. Do you have the answer in terms of "Dew plate". I have the same Problem, where to put the dew string?

[@Aero19612]

I've only had 3 cloudless nights in the past two months so not able to test thoroughly. I've tried two places: (a) on the thick cell (as shown in the video) and (b) on the tube just behind the cell. I did get dewing in the center of the corrector plate (not around the perimeter) with the strap on the thick cell. So it did help some. But dew in the center might as well be dew everywhere. I got some dew on the plate for (b), but couldn't tell a difference in the images. I think I like the strap on the tube. I can slip it under the mounting rail for full contact all around. Also, when I suspect dew will be a problem, I turn up the heat to about 80%-90% well before dew can form just to give the heating element time to heat up the tube and the air behind the corrector pate. I run off the mains, so battery charge isn't an issue. Then I cross my fingers. Some people say heating the air in the tube will cause image artifacts--I just can't believe that's an important consideration. I'm going with the strap on the tube for now. I will update when I learn more. Thanks for watching!

[@davidf9494]

Great video James! Have you thought of using a wireless router and connect indoors without a cable. I ran cable for a couple of years and now use a Mini PC on my SCT (EDGE HD8) and a tablet to control everything. The LAN has a range of about 100'

[@Aero19612]

Thanks, David! I would love to go wireless and have thought about it. My big concern is bandwidth and a somewhat spotty signal between my setup and indoor laptop.

[@davidf9494]

I had the same problem James with our WIFI giving only one bar and the signal dropped often enough to try something else. The very inexpensive travel router and creating a LAN worked well so I always get a full 5 bars on strong signal. It also means I don't have to rely on WIFI when I'm at a dark site.

[@Aero19612]

Very interesting. I'll look into it. Thanks for the tip!

[@Androcentus]

I have a nexstar8SE and teh celestron focuser..>Every time I try to focus in skysafaripro it goes back and forth usually passing through the correct focus...It drives me nuts, any idea how to fix this? Thanks.

[@Aero19612]

Hmm. Several things: Does the final focus position provide good focus? I'm not sure what focus algorithm SkySafari uses, but typical autofocus routines move the focuser out, then pass though optimum focus taking pictures at several steps along the way, fit a curve to the data, then move back to the optimum focus point. Also, the Celestron focuser uses a backlash compensation method that REALLY move the focuser a lot. So, maybe it's doing the right thing(?). Thanks for watching!

[@RobB_VK6ES]

If possible you might try upping the voltage supplied to the PPBv2 to compensate for drop over the cable and mosfets. Like DRonnieg I use a local computer and gigabit network cable from a remote computer to mission control computer. In my case the remote is a Pock Pi 4 similar to Raspberry Pi loaded with EKOS/ Indiserver (similar to the ASIAir). APT now has the ability to bridge from locally installed Ascom devices to a remote Indiserver. See indilib.org and APT help >indigo indi for more details

[@Aero19612]

Hey Rob. I'm plugged into the house main. Shows I'm getting 13V. Not sure I can increase. What's weird is that startup portion within NexRemote is "odd" when powered thru the UPBv2-- it's slow to respond and tells me I have an Advanced VX instead of saying "CGEM Ready" in the display. There's no load due to slewing at all--just screws up from the get go.

[@RobB_VK6ES]

@@Aero19612 Probably No 1 thing to check is the RJ12 extension, that may be causing the fault. Next maybe connect a car battery to test with a low impedance pure DC source. The other thing that comes to mind is a ground fault or loop. A complicated power system with no common ground or broken ground can cause all sorts of issues with back feeding and the like. Rant/ time. I had to get my hand controller replaced recently as it did not recognise the mount as a CGX but rather an Advanced something ??? The hand controller had been used literally a handful of times always indoors for testing it even had the screen protector still attached. If I could find a buyer for the CGX I'd sell it in a flash. I don't like the lack of openness of the Celestron ecosystem and being tied to Windows. I registered with Team Celestron to closely follow the development of the CPWI software. It is obvious the dev "team" is too small and out of touch with what users really need. As you may know CPWI grew out from Celestron licenced PWI IP and was originally intended for CGX and CGX-L mounts. Now it is being developed in house by what appears to be a single Dev to cover nearly all the other mounts in the lineup as a Next Remote replacement. How long since the launch of the CGX? 2 years? and we are still waiting for a stable and usable version. I bought the CGX on the recommendation of a prominent KZbinr. Had I exercised due diligence I would not have bought it so I only have myself to blame for the dissatisfaction.

[@Aero19612]

Checking the RJ12 from the mount to the HC is a good idea--hadn't thought of that. The symptoms of my under-powered mount ended up showing me "Advanced VX" as the mount type instead of "CGEM Ready". That's probably what you're seeing. Rant is all ok. I keep thinking Celestron is becoming more serious about catering to astroimagers. I had hope that the CGX reflected that. I know people who have one and it works great and others who have one and have nothing but problems. The essence of early product reliability issues. I'll get a new mount one day. Not sure what I'll get--don't want to spend $10,000. I prefer the $3,000 price point. The iOptron CEM60 keeps coming up. Oh well, not anytime soon. Thanks for the suggestion

[@RobB_VK6ES]

James you might want to look over at pegasus they have a new mid tier power box announced. Interesting thing is they mention exposing environmental data to imaging software via their 6.4 ascom drivers. The new power box is to be known as powerbox advanced. They specifically mention SGP and Maxim as retrieving the enviro data. I expect any protocols they have in place will be available to the PPB pro. Perhaps a feature request to Ivo at APT for inclusion of the enviro datastream

[@Aero19612]

Yeah, I've been meaning to do that. I checked the APT forum--people have mentioned the desire to access ASCOM temperature sources. Ivo says it's coming this year. I also mentioned that it would be nice for the focuser algorithms to have access to this information as well.