Cosmic Geoff

If you think the lead is holding the weights in place, then applying sufficient heat from a gas burner etc will melt it and free the weights. In commercial mounts, the weights have a clearance hole and are held in place by a side screw with hand knob, backed up by a safety cap on the end of the rod. If you can get these weights off, you could replace them with commercial weights - at a cost. Otherwise you will have to drill & tap a long side hole. Or fix a common circlip on the shaft below the weights.

I assume this is not much different from polar aligning the EQ5 mount which also has a central hole. Rather than crouching to peer through the hole, it is actually easier to mount a scope in the 'home' position and use its finder, followed by a look through the main scope (at low power) to confirm you have the mount set in the right direction. You should then be able to look throuh the axis (probably after moving the scope to horizontal) to confirm you can see Polaris. In an urban environment, the extra light grasp of a polarscope makes it easier to see Polaris and fine-tune the alignment. If you have got this far, this ia more than good enough for visual use, but if you are taking images with a long focal length and long exposures it may be necessary to tweak the alignment further. In which case I think you will need the polarscope and polar adjuster, which will certainly make the process less trying. Note that there are electronic methods of gaining an accurate polar alignment for imaging purposes (which assume you have mechanical adjusters that work smoothly). I assume 300mm is the focal length??

Depends on how much you want it to work and how much time and money you are prepared to invest. To bring it up to the standard of a manual equatorial mount, it will need a RA drive & slow motions designed and fabricated, part of the DEC drive to be designed and fabricated, the weights cut down to size and paintwork done. If you have to hire someone to do the work, the costs could be significant. If it's a Project to restore a loved mount, carry on. If you just want a mount for your 8" Newtonian, order a new one and get it by next week.

Looking at the photos, it appears that any RA drive is entirely missing, while the gear (?) on the other axis is for a declination drive. It looks like a significant amount of work would be needed to provide hand slow-motions or motorized drives. Judging by the number of counterweights, assuming they are all solid steel, the scope originally fitted must have been unusually heavy. My 8" Newtonian required two 5Kg counterweights IIRC.

I have tried unguided imaging with a C8, and ASI224 MC camera. At f10 most images were so soft and small-scale as to be almost unusable. Results at f6.3 were much better. I think the seeing affects the softness of the images achieved.

The choice depends on how much you value the GoTo function. In turn this depends to a degree on whether you live in an urban area (where the GoTo scores) or im a location with dark skies. Of course you can see more objects with an 8" ... if you can find them. But even a 130mm will show you plenty. If you want to do astro-imaging, you should aim for a small scope on an equatorial GoTo mount. An 8" Newtonian on a (massive) equatorial GoTo mount is not ideal for a beginner in astrophotography. If you get the 130 SLT you can dabble with astrophotography and EEVA (q.v.) - at least enough to let you see the potential. I tried EEVA with a 4" reftactor on a SLT mount and was astonished at the results - the results onscreen surpassed what was visible visually with a 8" scope at a darker site.

Apparently with older SCTs the primary, secondary and corrector plate were figured as a set, rendering replacement of one component impractical. Hence the advice to mark the orientation of a corrector plate before removing it. With later SCTs and improved production methods, it is said that the orientation does not matter and parts may be replaceable. One of the links above is to a 3rd party maker of replacement corrector plates, which one assumes work with recent SCTs. Unlucky owners will have to compare the cost of repair with the value of a used SCT.

If the corrector plate is cracked, the scope may be effectively scrap, unless its optical performance is unaffected.

The issue is not unique to your mount. Slide the counterweight up the rod toward the mount. If that's not sufficient, buy a smaller weight, or see if the mount simply ignores the imbalance. I bought a smaller weight for my EQ-5 - I think the weight was intended for an EQ3-2.

I would rate a GoTo mount as essential. As noted above, all the serious imaging mounts have GoTo, and though you could use an electrically driven mount with ST4, you will be spending half the night trying to locate your objects instead of getting them within seconds with a "Platesolve & Resync". The GoTo mounts are also said to have more effective motors.

I tried imaging some galaxies on the 4th May and on examining my image of M60 I found a bright star between it and NGC4647 that wasn't on internet images. A quick search established this was the supernova. Taken around 22:44 BST with 102mm achro, EQ5 Synscan, ASI224MC, 1304x976px, stacked 10 frames of 29.6 secs, sky transparency poor, crescent moon.

I would suggest that swapping the visual back or diagonal is not a priority. Your money would be better spent on replacing the kit 9 or 10mm eyepiece with something decent ( budget around £50, or more if you like). As for finders, bear in mind that that you should only need to use the finder once a night if you are using the GoTo. I put a straight-thru 30mm finder on my Mak. The Nexstar version of your outfit (from Celestron) does not offer up objects (e.g. planets) that are below the horizon. With the Synscan, it should display the altitude and azimuth, allowing you to see where the object is and choose whether to GoTo or abort. My Synscan handset has one or two buttons that do not respond unless pressed firmly.

I already checked ages ago and they were totally interchangeable. Could not see any differences asides from the paintwork.

I don't know, but the AZ4-2 steel tripod is identical to the EQ-5 tripod.

My experience of alignment with the similar EQ-5 Synscan is that it can perform well if you do a two-star align with two stars both on the same side of the meridian (e.g. East), and then GoTo objects in the East. Go anywhere else (e.g West) and the GoTo is so inaccurate as to be useless. I have a Starsense and find it convenient but not particularly accurate. The alt-azimuth Nexstar GoTo however performs well with a two-star align anywhere in the sky.

I'm sure it is technically possible, but whether the astro equipment manufacturers have the funds to develop one and the astronomy community have the cash to buy it in significant numbers is another matter. An alt-azimuth mount with a Starsense-like plate-solving self align, coupled with a field rotator, ought to do the job. The mass-produced Chinese mounts have never been re-designed from scratch - for instance why does a USB port (if provided) need a serial driver? There are some nice mounts from specialist companies, some of which may actually do what you ask, but at prices that make one exclaim 'HOW MUCH?!'

There is a reducer for the C8 - known as the Celestron f6.3 reducer. ( so called because it converts the f10 C8 to a f6.3) They are not cheap - mine cost £100 used, and they go for more than that on ebay. New around £150. If you tell us what camera you are using, we can give you an idea of the FOV (or you can find out yourself with an online app).

If that's your aim, your DSLR might suffice for imaging the moon, but for the planets you really want a dedicated astro camera e.g. a ASI224MC that can take a video to be processed later by 'lucky imaging'. For a telescope for planetary imaging, I would recommend a medium aperture SCT, eg a Celestron C8 or C9.25 (though you could use a Newtonian). For a mount, an alt-azimuth GoTo mount will be entirely adequate (but if you envision deep space long exposure imaging you may prefer to use an equatorial GoTo) Note that some combinations of camera and telescope will not get the whole Moon in field. I've already spent more than your £2000 budget for you. 🙂 You will need to decide on your main interest and priorities. As others have hinted, you can't cover everything with one set of kit. So far as imaging goes, I have one outfit for widefield & longer exposures & EEVA (q.v.) - (on equatorial GoTo), and another for planetary imaging and shorter exposures of small objects (alt-az GoTo).

As I already said. One can buy cheap ex-business Windows laptops which work well for astro applications and run all the free astro programs.

A comment that you have not had this problem with your EQ-5 Synscan would be useful. The picture above shows the mount in the collision position.

You could get a Startravel 102mm achro refractor. It costs about £200, so worth considering if you can't afford an ED or APO.

You could consider selling the Celestron Nexstar Evolution C6 as a complete package, and then re-purchasing a C6 OTA (or whateber OTA you want). Why? The implied value of an Evolution mount is high (check the relevant prices) but you might not get much for it if you try to sell it separately as an alt-azimuth mount for small short telescopes. As a guide price, you might attain for the package 66% of what a new C6 Evolution costs. If you are going to use the mount as a camera tracker, you need to figure out how to do the star alignment. It might be better to dispose of it and get a dedicated camera tracker. As a guy at my astro club pointed out, these relatively new devices are becoming increasingly capable.

I had an odd event with my EQ-5 Synscan last night. I was using it to image EEVA-style some galaxies in Coma Berenices, east of the meridian. All good till I commanded it to find one with an azimuth of over 170 degrees (i.e. just east of the meridian), and a lower altutude. The mount proceeded to do a meridian flip, and I did not realise anything was wrong till I found that stars on the laptop screen continued to trail, accompanied by some odd noises. Eventually I spotted the problem with the aid of a torch - the declination motor, now on the east side and below the declination axis, was colliding with a couple of connectors on the fixed box on the east side of the mount. I recovered it by commanding it to go to another object. The mount continued to function, but now needing a platesolve & resync to find objects. Anyway, it was now aiming on the other side of the meridian from the two alignment stars. I have been using the mount for over a year and have never had this happen before. I thought this kind of thing couldn't happen. And why did the mount flip itself before reaching the trigger point of 180.0 deg azimuth? And what can I do to stop it happening again, other than keeping a wary eye on what it's doing?

Aperture counts for general observing, so that points to the 127mm Mak you have shortlisted. The only notable thing it won't do well is show wide star clusters. Some of the nearer galaxies are also wide, but in practice they are a disappointment visually. Unless you live in a dark skies area and have a bigger scope, all you will see is a dim glow representing the central nucleus, fitting easily into the Mak's FOV If you want to see galaxies, take a big scope to a dark skies area. Or try imaging them - with modest kit you can get a better result from a town than you'll get visually with a big scope at a dark skies site.

I am not clear what you have and what you are trying to do. You have a manual mount? And a Synscan handset? But no motor control box and no motors? Having a USB port on the handset just means a few less bits of cable and hardware needed to connect it to a PC or laptop. Unless you want to make a hobby of obtaining motors and building a motor control box and programming it, I think your best course might to sell the mount and handset for what you can get, and then look out for a used Eq3-2 Synscan or a EQ-5 Synscan. The latter should be a better mount and more widely available.