Cosmic Geoff

The APO scopes you cite are fine instruments, but I don't think they are necessarily what you want for a first astronomical scope.  Reflector scopes are even better at eliminating false colour.  It is quite likely that you will want to replace your 'first scope' with something else as your astronomical interests develop.

You express an interest in GoTo. If you will be observing in a light polluted area, this would be a decided advantage in finding non-obvious objects to observe. If you are not initially interested in long exposure astrophotography, or in visual only, then get an alt-azimuth GoTo.  An alt-azimuth Goto can be used for short exposure astrophotography and for planetary imaging.

I would suggest that should you buy a 150mm APO and a suitable GoTo mount, you will have spent an impressive amount of money and acquired a heavy outfit that may not necessarily suit your ongoing requirements.

I recommend that you give up the idea of buying a "lifetime scope" as your first purchase, and instead buy a smallish telescope (e.g. 127 or 130mm) and alt-az GoTo package. This might cost around £500 (600 euros?) and would provide an adequate introduction to astronomy.  If subsequently you decide you don't like the scope or the mount, or the tripod, or for that matter GoTo, then you can do something about it without much financial pain.   More to the point, having acquired some experience of handling an astronomical telescope and mount, you will be in a far better position to buy an outfit that suits your needs and interests.

You might even have decided that you want More Aperture, which in practical terms means a Newtonian reflector or a SCT.

On 11/03/2020 at 13:02, daslolo said:

yes, it's about deforking, what i want is dovetailing that fork mount, to put other otas on it

Not sure exactly what you want to achieve. You could piggyback a scope of substantial size on top of the fork-mounted C11. Considering the size and weight of the assembly it will just shrug off the weight of a smaller scope.

Is the C11 permanently mounted in an observatory?

I suggest that the probelem is the mount, and if you had a more stable mount, you would not be looking for an electric focuser.  Fixing the mount is easier said than done, but you could for instance look at gettng an EQ-5 style tripod and making an adaptor plate.

I suspect that some of us are getting frustrated by the OP's apparent inability to deliver a detailed report of the problem, while the OP is hiding from a barrage of techy messages.

I did not have anything to do this afrernoon other than try to compile the following, namely some simplified instructions for the OP which also suggest what could be going wrong, if in fact there is a tectnical fault.

I downloaded the Startracker instructions and have copied some relevant passages along wih my own notes.  These notes cover the initial setup of the Polar Home Position and a one-star align.

Setting the Polar Home Position1.  (page 8 Level the mount, if necessary, by adjusting the length of the three tripod legs.2.  (etc)
A bit wordy.
 In plain English, Polar Align the mount, then with counterweight and telescope fitted, position the counterweight at its lowest position (over North leg) and the telescope above the mount and pointed at the pole star.  Do all this with the power OFF.  The setup should look like Fig 3a in the Manual.  If you do not start from this position, the following setups will not work.

Skip a lot of stuff to Page 13 "Initializing the Handbox" (sic).
This section makes reasonable sense (to me, at least). Engage the RA and DEC locks before you start, otherwise you will lose your setup as soon as a clutch slips.
It doesn't say exactly how you enter the numbers, (and I have not been able to see what the display actually looks like) but probably you can select number groups with the arrow keys and then enter numbers with the numbered keys (or whatever)
You can skip through the Daylight Saving by pressing Enter (or so I assume) No daylight saving this week.
Location: Cornelius Varley helpfully provided the Lat/Long for Dartford, and I am copying these details here. "Your location co-ordinates should be similar to E000 13 11 , N51 26 38 (the centre of Dartford). "
If this looks too confusing, use the other option and select your town and city. "London" will be good enough for now. Time zone for Dartford (or London) is 00.
This should conclude the data entry and the next step is a sky align.

Make sure the telescope & mount are at the Polar Home Position and the clutches are locked.
Press 1 x the ENTER button to access the main menu and select the menu item „Alignment“. Then press the ENTER button. Different alignment methods to choose from now appear.  Select „One Star“, and then press the Enter button.
Do what it says, I guess. Use One Star to start with as this is the simplest option.  I am assuming that you will recognise the alignment stars and where they are in the sky.  Pick a likely one and press Enter. The telescope should slew to the (first) star.
What's happened now? The mount should have slewed to the star with at least finderscope-field accuracy, but if you did a good job earlier it may be in the main eyepiece field.
Did it work? The next stage is to centre the star using the direction buttons and accept the setting.  

Something wrong? There are various possibilities.  With 'Another Clone Mount,' doing the final centering kicks up a fair racket, despite the slow speed.  So you should be able to hear if the motors are still working.
Your power supply may not be man enough for the job of slewing the loaded mount without developing a glitch.  Are you using the supplied dry cell pack? Maybe those batteries are past it several months after purchase.  Or did you buy them from Poundland? They'll be rubbish.  I made that mistake once. Get a new premium quality set.  

Or did you use one of the popular power packs that work fine with Celestron and Sky-watcher mounts and lots of others? Did you know that the Exos-2 mounts use a different standard of power plug from everyone else? Here: (from the manual) Connection power supply: DC- plug 5.5/2.5mm.
If you try using a power source with the popular 5.5/2.1mm plug the results are going to be unpredictable.

Another possibility is that some cable is getting snagged in the dark as the mount moves, with unpredictable results.

Paul - I hope that some of this helps.

11 minutes ago, paul schofield said:

Oh really, good spot sir. A bit vague indeed. I have read and read it so many times. 

That's not really the point. Did you polar align the mount and aim the telescope at Polaris (with power off) as the starting point, or did you do something else?

Firther down it says "5: If steps 1 through 4 above were performed with reasonable accuracy, your telescope is now sufficiently well-aligned to Polaris, the North Star, for you to begin making observations. "   which makes their intent clear enough. Particularly with reference to the clearer EQ-5 Synscan instructions which cover the same ground.

1 hour ago, michael8554 said:

Bizarrely you have to read the pdf manual for the Goto kit, not the manual for the mount !

I managed to find it. (I should get a prize).  Reading through this, the directions for the initial Polar Home Position align are a bit vague, but it seems to be the same as for the EQ-5 Synscan cited above. The one star, two star align etc seem to work as for the Synscan.

I tried finding a manual for the Exos-2 Startracker but could not find one. Failing that, I have been reading through the Synscan GoTO manual (since I should be getting an upgrade kit delivered later today.

Nobody has picked up on my point above about pre-align.  With the Synscan, you have to polar align the mount, aim the attached telescope at Polaris, and then turn the power on.  The system now knows roughly where it is: mount setup and level, scope pointed at Polaris.  (And if it isn't, don't expect any of the following to work) If you go for a one-star align on Rigel, select Rigel and the mount will slew till Rigel is in the finder field (we hope). Centre the star in the finder then in the main eyepiece. Job done.

I assume the Exos-2 works either in exactly the same way or close enough so you can figure it out from the manual.

If there is a function to return to the start position, execute it and see what happens.

Badly behaved electronics can often be fixed by that old engineer's trick - turn the power off, count to two and turn it on again, or  a factory reset.

I have looked at my ZWO ADC (which does have the bubble level).

No rattling, no parts at odd angles.  Just a black body with two levers (and the bubble level) sticking out. To adjust it, I move the two long screws in their slots, in opposition.  No need to tighten or slacken anything.

As I understand it, both the optical elements are thin wedges, and rotating them relative to each other creates some colour dispersion to counteract that from the atmosphere.  I hope that helps.

I can't find any info. Picture please? Or link to a aimilar one?

One hopes that somebody familiar with the Exos 2 will respond.

One assumes that some pre-align is involved here.  Otherwise why is the mount slewing to Orion (even if it's wrong)?  Is the mount really not moving at next stage, or just moving slowly?

I can confirm that the SLT mount has a slip clutch on the altitiude axis but not on the azimuth axis. The reason for this (I assume) is that the mount can spin around in azimuth as much as it wants, but with certain scopes/accessories in place, aiming too near the zenith will result in a collision, and something has to give (preferrably not the diagonal or the Alt gearbox).

The altitude slip clutch may be too loose and can be tightened, (see above) but don't overdo it.

If I were you I would lose the Wedge. The moon is bright.  You should be able to image it with an alt-az mount.

Perhaps it's rude to spend other people's money, 🙂 but you could buy a German Equatorial mount, suitable for imaging (with auto-guiding, etc) to mount the second TAL 200K.  Then you would have two great setups, one for visual and quick imaging, the other for dedicated long-exposure imaging.

It appears that the TAL 200K is no longer in production, but to break one for spares seems rather a crime. 😲  I can't see the need arising unless you drop one and wreck it.

Yes, the weight of the C6 OTA will vary depending on what exactly is attached to it. This should not matter unless somebody is trying to create the lightest possible assembly.  I am a little unconvinced with Celestron's efforts to bundle the C6 with the Astro Fi mounts.

So far as I can see from your post, the  C6 OTA weights around the same as my 127mm Mak (but is physically bigger) and the Astro Fi mount and tripod look mechanically similar to my  SLT mount and tripod.  My stuff works, but I have never been impressed with the stability - the tripod is too wobbly.

The C6 OTA also can be bought bundled with the much more expensive AVX (£1511) and Evo mounts (£1346). I rest my case.

Dare we ask what the second TAL 200K is mounted on (if anything)?🙂

You might be disappointed by the ultimate selling price, especially if you hope to avoid the bother of postage and packing. I suggest you write it off and put it in storage. Sooner or later you may want to rob some part off it that you might otherwise be paying good money for: a slow motion control, a finder, a weight...

The Evolution mount should work fine without the wedge for any visual work.  It will also be fine for many imaging exploits, such as planetary imaging, or anything else that only needs a short exposure.  I managed to image a 11.5 mag galaxy (just about) using an alt-azimuth GoTo mount.

You don't say what size of  SCT and tripod you have.  Some of the EVO tripods look the same as the budget SE tripod. I have one of those and while it's adequate for visual use it's definitely not what one would choose for imaging anything. The CPC800 and (I think) some EVOs come with a heavy duty tripod which is far more stable.

16 hours ago, Jupiter1 said:

another problem that I have is that when I move the axis in slow motion ,say number 3 it tends to run on one way ( I think it is the Positive side in the Gear compensation (Backlash ) I have not found how to improve that yet.

Yes, if you tilt the mount there will be a tendency for it to run 'downhill' unless carefully balanced. It may happen with German equatorial mounts too but they have counterweights and more 'scope' for adjusting the balance.

In contrast to many domestic appliances, updating the firmware on a Celestron mount or handset is not such a simple exercise, and may entail buying extra cables and downloading some installation programs.  You can check the level of firmware in the handset and mount from the menu.  Then you should read all the "small print" for these revisions and decide whether any upgrade is relevant to you (see Noah 4x4's notes) or whether you would prefer to leave well alone.

As replies above, the first thing to do is to estalish that the collimation is correct. When I received my (used) C8SE the performance and the collimation were both awful, but I soon managed to correct it.

Then we come to other matters that will affect the visual performance.  The C8 is big enough to be  substantially affected by poor 'seeing'.    You will find plenty of pretty pictures taken through a C8 which bear little resemblance to what you see through the eyepiece. The main reason again is the 'seeing'.  The popular planetary imaging techniques involving making a video which is then processed to get rid of all the crud and bad seeing and preserve only the moments of excellent seeing in the final image.

In fact I moved to planetary imaging (with specialist cameras) to see the planetary detail my telescopes were capable of revealing.

Given the large focal range of a SCT it should be possible to get any camera in focus. Are you making the camera look through they eyepiece, or using the telescope as a telephoto lens?  Once you have a focus, it is a good idea to put the eyepiece back on and note how far (usually) you have to pull it out to get a sharp focus. That should give you a reference.

What finder are you using? Whatever finder came with the C8 may not be adquate for imaging, where you will want to locate your subject using the finder only. I recommend at a minimum a 9x50 RACI (right angle, corrected image) finder.

57832 looks like a typical Ross serial number. Probably early 20th century.

This seems to be the same Nexstar as the ones I use.

Why are you setting up in the daytime?

If you want to observe the Sun (with filter), then if I remember correctly, you just have to do a solar system align and choose the Sun.  Or align on the Moon- you can't use both.  It should be easy.  IIRC, the alignment mode ( 3 star, auto 2 star, solar system, etc) is one of the first things you select on setup.

By the way, even though Celestron supply these wedges and charge a lot of money for them, I have seen few people, if any, have a good word to say about the results, when compared with putting the OTA on a German Equatorial mount.   You are unlikely to need the equatorial except for long exposure photography (is that your aim?). 

I hope that helps.

I have a 70mm Ross vintage scope which has a fairly long focal ratio (significantly longer than f10), a tapered tube originally sheathed in leather (now leatherette)  It was originally sold, post-war, by Charles Frank of Glasgow as an astronomical telescope, The focus barrel takes a 32mm Huygenian for which 31.7mm astro items can be substituted.

A lot in your photo looks non-original to my eye. In particular, the white tube and the white joystick and black slot.

If you quote the serial number, (preferably via a photograph) it will give  some idea of your scope's age.

1 hour ago, Tomatobro said:

Flo do them for £28 if I have got the right one

Don't buy the cheaper drive which is an all-in-one running off a PP9 battery. I had one once and it was awful. I ended up binning it.  There is a more expensive version with a separate handset and battery pack, which looks more like the drive kit for the EQ5. I have one of these for an EQ5 and it works very well.

This looks very ambitious for a "first telescope". It appears that no expense is being spared. 🙂 Starting cheaper and simpler could save you money in the end.

The jack socket is the size used on various mounts. It is a 2.1mm (inner) 5.5mm (outer).   I'm surprised that you managed to break the socket rather than the plug or lead, though, as the socket seems relatively robust.

I thought of changing the jack socket on my C8 SE mount because it was making poor connections, and got as far as buying a replacement socket from the now-defunct Maplin, but I found I could not find a box spanner slim enough to undo the outer nut, so had to give up and find another solution. These sockets often cause trouble with poor connections.

I'll just throw out some ideas here which may or may not be helpful: 🙂

Just because the mount is supported by rollers under the horseshoe, that does not mean you have to drive it via the rollers.  If you drive it via a metal gear and worm placed at the lower end, then the drive train can have the same sort of worm wheel and worm, motor drive train, electronics and software as in mounts such as the CPC800, EQ-6 etc.  The CPC series mounts rotate a fork on a turntable driven by a large worm wheel and worm. The same remarks apply to the declination drive.  In fact you might be able to recycle the whole system from a scrapped mount.  So no need to invent your drive train, electronics and software from scratch.

I have not seen mention above of the requirement to have high speed slew rates (several hundred times the sidereal rate) which are a standard feature of GoTo mounts.

You do not necessarily have to use stepper motors. IIRC some mounts use DC servo motors.  The SLT mounts have a simple encoder on the end of the motor/gearbox, obviously intended to count the motor revolutions.

It's possible to spend a lot of money on monitors for image processing, but I am not sure how far you need to go for astro pictures. I processed a lot of holiday pictures on a CRT monitor before realising that it was persistently too dim in the dark greys and blacks. On the other hand the screens of my Dell Vostro and budget LCD monitor seem okay.