Cosmic Geoff

Your options are: Investigate 'equatorial platforms' Trade the whole outfit for a variant that has GoTo. Fit a push-to encoder system, e.g. Nexus, but don't expect this to be cheap.

You have three options: investigate the equatorial platforms. Trade the whole outfit for a Skywatcher GoTo equipped version. Fit a push-to encoder system (e.g. Nexus) but don't expect this to be any cheaper than a GoTo.

Last night I was obliged to operate my CPC800 without a dewshield because the weather was so windy. After some time I checked the corrector plate with a torch and noted that it appeared to have condensation on the inside as well as the outside, to the point where I wondered how it would affect the imaging. I had not expected any dew to form in a high wind. I left it for some time with the dewshield on, and the tube horizontal, and most of the dew (inside and out) seemed to go away. I recall another member complaining that his observatory-mounted SCT got condensation on the inside of the corrector plate. I think what was happening here is that (as I read elsewhere) the sky is very cold and the faceplate radiates heat to it, cooling down to the point where condensation occurs from moist air inside or outside the tube. The moral of this story: always use a dewshield even if you don't think you need one.

All ZWO cameras don't use the same bayering scheme. For USB3 to work, all the relevant ports and the cable have to be USB3. I'd expect it to default to USB2 if not.

That seems a lot. I have two Dell Vostro laptops of different ages, and actually measured their mains power consumption once running. One (with HDD) consumed 20+ watts, and the other (with SSD) about 7 watts. For reference, 5 amps at 19.5v = 97.5 watts. If there is a Dell +12v adaptor, the obvious choice is to use it (and read its spec. sheet first.)

A few clues: I have a 102mm f5 Startravel, which when used with an ASI224MC camera, performs plate-solving reliably. I found that plate-solving could work with my CPC800 + f6.3 focal reducer + camera, but only tried it once. I fitted an ASI120MC camera to an Astro Essentials 50mm finder/guidescope, hoping to use it for platesolving + aiming, but found it only worked when aimed at dense starfields, e.g. the Pleiades. Plate-solving ought to work with your WO GTF81, but you will have to figure out how to swap between eyepiece and camera. Maybe use a flip mirror diagonal? If you were using a Celestron Nexstar mount I would suggest using the Precise GoTo feature instead of plate-solving, but Skywatcher's Synscan does not seem to have an equivalent feature. 😁 In fact I found my Synscan GoTo to be a bit rubbish in the absence of plate-solving, even without the hindrance of a Wifi connection. Celestron do a plate-solving app for smartphone, but you have to buy it bundled with a telescope and special camera holder.

Seems a further reason for selling it as-is and letting this be somebody else's problem. Unless the muck comes off when carefully cleaned.

No it doesn't. Surely it was re-coated before the stain occurred. I should have thought that stripping and re-coating would have got rid of the stain if it was there, or somebody would be wanting their money back. It seems more likely that dirty water has got into the scope and dried on the glass, on top of the coating, leaving a deposit of muck. Clearly an attempt should be made to check or remove the stain before any talk of re-coating. If you feel confident about removing the corrector plate, try cleaning a small area of stain with a cotton bud stick and see how that goes. If you don't want to, my advice to the executor would be to sell it as-is. (If you imagine that rainwater is clean, you should check the crud that collects in the bottom of a rainwater barrel after a year or two.)

If you're happy... Note though that I am not recommending the Celestron x-cel LX eyepieces, I just happened to acquire a set along with another used 'scope. That is likely to remain a matter of opinion. I have a very similar zoom of a different brand, that cost no more than a single budget eyepiece. Optically good but mechanically stiff, and with restricted FOV at lower power. The Baader Hyperion mkIV zoom (~250 Euros) is said to be good. Get a dew shield (or make one). Don't buy a dew heater until you have used the scope with the dew shield and have ascertained whether the dew shield is sufficient or not at your particular location/pattern of use. I have never used a dew heater and while I have often been annoyed by the finder dewing up, deploying dew heater power supply and wires every night would also be annoying.

I don't think that professional dismantling and cleaning, though good for the scope, would be cost-effective for the executor. Better to sell it off cheaply to someone willing to take a punt on being able to sort it or use as-is.

Guide price for used SCT = half the price of a new one. As PeterCPC says, it would be worth trying cautiously to clean it. The brown stain may turn out to be muck rather than corrosion of the reflective surface. It would definitely be easier to sell without the stain.

Have you tried re-soldering the joints on the controller board and renewing any electrolytic capacitors, especially if they have bulged? If there are any ICs in sockets, pull them up and re-seat them.

If you bought it new, it will be under warranty so contact your dealer. If it was used, 🙄. I doubt that the weight of the scope and camera is to blame. If you can, swap over the RA and Dec motors, or their connections, and see if the fault moves. Also check the motor wire connections.

Depends what you mean by 'mid level' and 'upper level' eyepieces. Your proposed purchase, the C8 SE, has a focal ratio of f10 so will not require exotic eyepieces. If you buy branded eyepieces from Celestron, etc you should be OK. Plossl eyepieces (like the 25mm you will probably get with the outfit) will be adequate for longer focal lengths, while you will probably want more complex eyepieces with longer eye relief for focal lengths like 8mm. BST Starguider are often recommended here. For instance I bought a 15mm Celestron Omni Plossl which seems entirely adequate for the C8. I have some Celestron X-cel LX which are okay, but one of those will cost you close to 100 euros. It is possible to spend hundreds of euros on one eyepiece but that would definitely be overkill. You should avoid very cheap eyepieces, as if they turn out to be poor you will not have anything to compare them with to judge the quality. Likewise don't buy a box set of eyepieces as you may find you use only one or two of them.

I actually use an ASI224MC camera and a 102mm Startravel on an EQ-5 Synscan mount for EAA imaging. I think some more research would be wise before investing in a large-sensor camera. Besides chromatic aberration, I noted that when used in daylight with a low-power eyepiece the Startravel had an alarming amount of pin-cushion distortion, which made straight television aerial elements look bent. It works okay with the small-sensor ASI224MC, but with a larger sensor, who knows what errors may become evident? I would think either leave well alone, or put money aside for an APO refractor in addition to a large-chip camera.

I wouldn't. The eyepieces I use with my C8 SE range from 32mm to 8mm. I never use a Barlow lens with it for visual. The focal length is 2000mm which means the highest useful magnification is attained with around 8mm on most targets.

Advice on what? Plenty advice is already posted here daily. Since you managed to restore this junk to working order, (marking you out as more skilled than many of the people posting here) you shouldn't have any trouble selecting some 1.25" eyepieces. It's a f8 Specifications - Meade 4504 Instruction Manual [Page 37] | ManualsLib so a set of budget Plossl eyepieces should do the job. e.g. 32mm, 25mm, 12mm, 8mm and a x2 Barlow

Agreed. This OTA is a bit too heavy for all the "Budget" altazimuth GoTo mounts, and while there are heavier duty alt-azimuth GoTo mounts, they cost even more than an EQ5 Synscan. An EQ5 is one of the few mounts that can be had in the basic (manual) form, or with electric drives, or with the full GoTo, and any of these things can be added to the manual version as aftermarket kits. An EQ-5 is a good mount to have, as it is fairly solid and you can hang all sorts of scopes, up to 9 or 10Kg (visual) on it.

Today I tried reprocessing some of my early efforts at planetary imaging from 2018. At the time I was using a C8 SE and a ASI120MC camera. Date: 6 May 2018. Pinkish image is original (1 video processed in Registax), next is from 2x .avi combined and cropped in PIPP, total 1500 frames, processed in AS!3 (30%), , processed with Registax & colour corrected. Larger image is from 3x .avi combined, total 1500 frames, combined in PIPP, processed in AS!3 (30%), , processed with Registax & colour corrected. The image scale indicates that I must have used a Barlow, but I have no note of this. According to my log this was a glancing transit of Europa. There are more videos from the same night, but I am having trouble combining the .ser files.

I think you will find that trying to do any astrophotography with this mount is a very instructive experience. 🤣 You may be shopping for a more substantial mount very soon.😀

You can reduce the height by retracting the tripod legs. But then you will have trouble observing low objects if there is a 2metre high board fence in the way... Large Dobsonians have similar issues. That's why it is advisable to at least see these things in the metal before buying... It should be very stable. We don't know what brands are available to you in Bulgaria. Celestron and Sky-watcher are OK if you avoid the very cheapest models. I've heard good things about some Bresser models.

I cannot imagine why a legitimate trader would not accept cards or paypal.

My setup actually does record 5000 frames in 18 to 20 secs , ( ~275fps) with the ROI of 320x240 PX. USB3 ports. CPC800 at f10 with ASI462MC, exposure 0.75ms (Mars) 1.65ms (Jupiter). 320x240 is a little tight for Jupiter so it took 40 secs for a larger 544x548 px ROI, and a .ser file four times the size as for Mars At '3.7x pixel size' it seems I am operating close to the optimum focal ratio. Indeed I found a 1.8x Barlow did not seem to improve things any.

Nice outfit, but on the downside I found the combination of 8" Newtonian + equatorial mount not very user-friendly. The eyepiece can attain an awkward position or extreme height. You could image with this, but the big tube will be a bit of a wind-sail. If you are willing to spend this much (or more) consider the Nexstar Evolution 8 (with 8" SCT) , the CPC800, or the C8 with AVX, which will all be easier to manage. The CPC800 is great for planetary imaging, and the AVX would offer more imaging options, depending on what scope you mount on it. The CPC800 is heavy... Be aware that if you are only interested in visual, or your imaging ambitions only extend to planets, you will find an alt-azimuth GoTo less of a bother to set up than an equatorial one, and equally effective.

Could be the seeing. It seemed bad last night (29th) and my images with C8, ASI462MC, were below par and generally no better than yours. Looks like you have enough frames. I generally find no benefit beyond 5000 frames (=20 secs). There seems to be some colour fringing in your image. You don't mention an ADC. It is worth using, especially if the planets are low in the sky.