Cosmic Geoff

How is the mount being powered? Is the battery pack maybe not delivering enough power when cold?  The wifi circuitry should not be sensitive to moderate cold.

3 hours ago, mikeDnight said:

Where the refractor scores for me at least, is in its laser etched sharpness, high definition and clarity of image at the eyepiece.

What specification of refractor are you talking about here? I have a 102mm f5 achromatic, and have not been bowled over by its visual performance.

I have had error 16 or 17 a couple of times with a Celestron SLT mount.

So far as I recall I fixed this by reprogramming the mount firmware with Celestron's MCupdate utility.  You can find instructions online.

If the polar alignment is perfect, you should not need to touch the DEC axis at all when tracking.

Yesterday (19 Jan) I was doing some daytime observing around 11am and commanded the GoTo to find the Moon. It pointed South at the garden fence.  I looked up the Moon's position and it was due south with an altitude of just over 6 degrees.  Remarkable.

With 3% illuninated, I probably would not have been able to see much anyway.

The scope could be used for planetary imaging, with a suitable astro camera.  It would only work for deep-space imaging of the most basic kind, with short exposures.  Upgrading the eyepieces, particularly the 10mm, and buying a Barlow lens, would be advisable.

If the mount has WiFi, the handset may be a costly optional extra.

Platesolving works perfectly with laptop + Sharpcap + USB cable to recent model handset + EQ-5 Synscan mount.

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.

7 minutes ago, MG01 said:

I'm trying to put together a power box and would like to provide 19.5VDC at 4-5A for my laptop.

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.

5 minutes ago, Chris-h said:

"Some mirrors we receive have been kept is wet conditions or conditions where moisture occasionally condenses on the optical surface and stays for hours, sometime days. This is one of the biggest problems which cause degradation of the reflecting surface. The moisture gradually seeks out microscopic pin holes in the top protective layer of a mirror’s coatings and begins, ever so slowly, to attack the aluminium underneath this layer. Over the years, this action can also attack the glass but to a far lesser extent. However, glass needs very little attack to loose a little of it’s polished finish.

Unfortunately, there are one or two cases a year when there is very little sign of any attack on the mirror’s surface and we consider that it will coat to a virtually perfect reflecting mirror. The problem is that when coated, we come across areas which are slightly duller which, were impossible to detect in it’s original condition or when the old coating was stripped off. Let me stress, this is a rare occurrence but, it does happen, even after we have given the mirror the most stringent visual tests prior to coating. The dulling of the surface in these rare instances is usually very limited and detracts only from the mirror’s appearance, it has little or no effect on the mirror’s overall performance. The only way to remove this attack on the mirror’s surface if it is very noticeable and which may detract from it’s performance, is to re-polish and re-figure the mirror. This is usually very expensive and in some instances not possible."

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.

2 hours ago, Chris-h said:

It also means the stain must have etched into the glass?

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.)

19 hours ago, Raychin said:

Well for a 100€ for an eyepiece, that i will use long time, is perfectly ok.

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.

19 hours ago, Raychin said:

Related to this does Celestron Zoom eyepiece 8-24mm 1.25" is something that will be useful or is a toy for a boy?

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.

19 hours ago, Raychin said:

Now i am after a Dew Shield and ring heater. I am not sure with what the aluminium Celestron Dew shield is better (or it’s not), compared to a soft one fro Celestron or from another brand?

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.

4 hours ago, Raychin said:

Thank you for that advice! I will follow it!

Can i ask about the eyepieces? Should i buy mid lvl brands and models or it is ok as a complete amateur, to start with the upper models and brands? I don’t imagine that i will see live image of Jupiter, Saturn, Mars just like in NG magazine!  But will be a noticeable difference of view between the different lvls of eyepieces with the naked eye gazing thought them?

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. 

2 hours ago, Raychin said:

some  barlow lens (2X),

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

40 minutes ago, Astronomist said:

For the skymax 150 an eq5 class mount would be the size to go for, at 5.2kg OTA only being somewhat to heavy for an eq3.

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.