Cosmic Geoff

Don't buy a focuser without checking out Chinese-made helical focusers. They seem to be intended for guidescopes but work fine as a screw-in fine focuser for a Newtonian. For pic see my Newtonian OTA post in the 'For sale'. That focuser cost me around £20 from China. be cautious if buying a motor for your EQ-2. I had a EQ-2 clone mount and bought the £30 budget motor for it. It was rubbish and eventually got binned. IIRC there is a better drive but it can't be transferred to another type of mount. Also a 130/900 scope sounds a bit chunky for an EQ-2 mount. Replacing the mount with something better should give you much more stable views, but at significant expense. I doubt that the Kellner eyepieces supplied will work particularly well with your scope (or anything else). I have not been impressed by similar kit eyepieces supplied with my scopes and found that an upgrade was worthwhile for higher powers. Apparently this telescope has a spherical mirror rather than parabolic and reviews suggest the kit is a low cost entry level instrument. Accordingly I would caution against buying upgrade components that can't be re-used with your next telescope. Eyepieces and standard mounts will in general be re-usable.

The EQ8 should serve well for the purpose. The forgiving nature of the 'lucky image' process means it is possible to get good results with a light portable mount like the Celestron 6/8 SE, but a solid and heavier mount is much less trying to use.

That's a possibility. The older ones have a smaller effective aperture, I'm told. You want a SCT (or the 180 Mak) as the focal range means you can hang all sorts of useful imaging accessories on it. I use a Celestron 203mm SCT. This is about the smallest really useful size and you might go bigger if your budget or other considerations permit. The results are strongly affected by the seeing and where I live only a minority of nights deliver really fine results. Spending more on a camera helps, I've found - a ASI120MC is the minimum and does deliver pleasing results. As for the mount, you don't need an equatorial but it does need to be something decently solid and well-behaved. And you need a good optical finder to recover the image should it wander off chip. And an ADC is essential with the interesting planets so low.

An ASI290MC seems overkill for a guide camera. If you bought it firstly for imaging, you really ought to have an IR-cut filter otherwise your colour images will not come out with the correct colour balance. The filter is not IMHO an optional extra. OTOH if you fit the IR850 pass filter instead of the IR-cut you can take infrared images. I bought the ZWO IR-pass and cut filters to go with my ASI224MC.

A few spots of rain should not hurt (think of it as coarse dew 🙂 ) but is best avoided. I have rarely been caught out, only once or twice. If a proper cover is not to hand, the ubiquitous black plastic rubbish bag may serve.

Having bought an ASI224MC and the ZWO IR-cut and pass filters I am able to image things in the infrared (IR850). Date: 13 May, kit CPC800, ASI224MC, ZWO IR cut or pass filter, ZWO ADC. Colour image: 20% of 5000 frames. IR image: 50% of 500 frames. Here is a pair of images of Jupiter. The conditions were not very good, but the comparison is interesting. The moon in transit is Io. The shadow is visible in both images. Io can't be seen in the colour image but a white dot appears in the right place in the IR image, above the Great Red Spot which shows white in IR. The Southern belt has a pair of tramlines, more evident in IR. Nobody told me that the required exposure for the IR image is about ten times longer than for visual, but it is. The required exposure time for the ASI224MC (in visible light) seems longer than for the ASI120MC. (counter-intuitive?) Can anyone who has both cameras confirm that this is the case, and by how much? Is there a proper way of processing the false colour out of the IR image? I just set a chrominance slider to the lowest value in Registax6. There was also a tickbox, but that made the image dimmer when it was dim enough already.

Scope handles are a very useful feature usually omitted by the manufacturers on budget scope designs. When I acquired a 200mm Newtonian OTA the very first thing I did with it was to fix a grab bar across the tube rings via the spare screw points. My C8 now has an equipment mounting dovetail/grab bar mounted on the opposite side of the tube to the main dovetail bar. Very useful when mounting up a fat OTA.

Planetary and deep space have quite different requirements. A Mak-Cass has a focal ratio more suited for planetary photography, but a 90mm is really too small. If you want to pursue both branches, first read the book 'Make Every Photon Count', then think in terms of a SCT and planetary video camera for the planetary imaging, and a small short focal length ED refractor, a DSLR and a large equatorial mount for the deep space imaging. Plus a wad of money. You can dabble with whatever you have to hand, but the results will suffer accordingly.

It has a long focal length and a narrow field of view, which I'm told makes it difficult to use for imaging, compared with a small short focal length refractor. In practice, you could image small galaxies with it, while a lot of other things will fail to fit in the FOV. If you have Stellarium and some camera specs you can see this for yourself by modeling what various things look like in the camera frame. I have played around with deep space EEVA using a Startravel 102mm f5 refractor and a ASI120MC camera, neither of which I bought for this purpose. Much easier to manage than using a f10 SCT.

I try to view it telescopically in the daytime form time to time, or spot it with the naked eye at sunset at a favourable evening elongation. Have seen it quite a few times now, and tried imaging it once or twice.

Nothing wrong with wedges on a fixed pier - the big LX200s are mounted this way for observatory installation. However in your case you should forget the wedge. AFAIK the Evolution mount is not ideal as a deep-space imaging mount, any more than the C9.25 is ideal as a deep space imaging scope. The wedge costs around 400 pounds, and you would be better advised to invest this sum toward a GEM mount like an AVX or HEQ5. Then you can put the C9.25 on it and demonstrate to yourself how grim a scope of this FL is as a deep space imaging scope. Then start saving for a small refractor. OTOH if you want to do planetary imaging, use your present setup with an astro planetary camera. It will work just fine - maybe not as fine as a CPC925, but well enough.

The SE 6/8 mount will let you slot the dovetail bar in sideways, so provided you have enough clear length you don't need to worry about the protruding screws. The smaller screws are for 'cone error'. (Look it up). But why are you doing this? I assume you are buying the 72ED for imaging (otherwise why buy such a small aperture scope?) If you try imaging with the SE mount you are heading for a big disappointment. It's adequate for visual with short scopes that don't weigh more than a C8, but for imaging it's awful. I invested in a CPC800 because the SE 6/8 mount was not good enough even for planetary imaging - too much backlash, drift and wobble.

My 102mm Skywatcher Startravel has sticking out bolts securing the dovetail bar to the rings. Not a problem with Skywatcher mounts and saddles, but to fit it on ny Nexstar SLT (which requires entry from the end) I had to countersink the bar and replace the original bolt with a countersink head screw (and remove 2x polar aligning screws).

This is rather like 'where should I buy a car?' It depends on whether there is a dealer near you, how much you know about scopes, and whether you want a popular model, or something exotic, among other things. Avoid buying a starter scope from a general store or supermarket. Safest bet is to educate yourself as far as possible and then buy from an astronomy dealer -either face to face or online. If you like a bargain, you can buy secondhand. Buying from genuine amateurs via a forum like this (or your local equivalent) is fairly safe and will save you money. You can buy used from dealers who sell used astronomy equipment with some confidence as they have a reputation to maintain. Savings vs new will not be so large. You can find bargains on ebay but this is more risky and there is the possibility of getting burned by less scrupulous sellers. If it looks too good to be true, then it probably is... Be aware that if you buy used you may get something as good as new, with extra accessories, but equally you may find that your used purchase needs some fettling before you can use it.

My 2p worth: I was unable to split e1 and e2 Lyrae with my 127mm Mak until I got a couple of decent eyepieces for it to replace the poor 9mm sold with it. These stars should be splittable with a 70mm refractor, and IIRC I managed it with my vintage 70mm Ross. x125 seems a bit low - I used x150, x 180 or more. With a Newtonian, good collimation makes a significant difference to the ability to split double stars.

You can try it. Adding weights may help a bit. Other possibilities - replace the whole mount if it's just a Supatrak. An EQ-5 will be an order of magnitude more solid at least. Make your own legs from timber - I did this for a permanent garden mount for SLT mount heads, but it was a lot of work.

An EQ-5 would be adequate for visual use, or planetary imaging - I tried mounting my C8 on my EQ-5 and it worked okay, the OTA weight being well within the mount limits. I did not pursue this route as dismantling the C8 SE rig and then doing polar alignment each time seemed too much of a faff. If you have deep-space imaging in mind it may be advisable to go for a heavier equatorial mount. A sidenote - it is highly advisable to provide your SCT tube with a grab handle at the back end, or on the other side of the tube from the dovetail, to reduce the risk of dropping it.

Camera requirements for DSO and planets are totally different. Most folks would use a DSLR for deep space and a planetary video camera for planets. An 8"SCT is an excellent choice for planetary imaging, less so for deep space. Is this the CPC800? For deep space you will most likely need an equatorial wedge which costs about £400 IIRC. Unless you are particularly wedded to using the existing scope and mount, you should consider re-equipping with the German equatorial and small refractor combo commonly used for deep-space imaging.

Fine if you can manage it, but I suspect that the 'screen' doesn't just unplug or unscrew, and to change it you will need specialist surface mount desoldering/soldering equipment that will cost more than a replacement handset.

A small DC motor might have permanent magnets for the field and a commutator to feed the rotor. The likely failure area is then the commutator & brushes. Given the modest volume of CPC scopes manufactured, I doubt that the motor will be unique to Celestron. You might try giving the motor a twirl and a squirt of cleaner/ lublricant (sold as "3 in 1" over here.)

If you look on the Cloudynights forum you should find some dismantling hints for the CPC800. At the back of my mind is something about rotary encoders with glass discs ? so check that and take care.

This is a CPC800? I own one. I have no idea what the problem is. Maybe take the covers off and have a look. Or arrange to get it serviced? You are sure it is not a bad button on the handset?

It seems that you are determined to buy the outfit you cite despite the advice given. ? If you are used to a dinky 4SE the weight and bulk of a 203mm Newt and EQ mount may come as a nasty shock. I would point out that the combination of 200mm Newtonian + equatorial mount, while often offered to beginners is particularly user-unfriendly. See my negative comments under "Advice on eyepiece" here. As for resale value, I paid £60 + carriage for my 203mm Newtonian OTA. The seller had been dropping the price in an effort to shift it. Re EAA, you should experiment with the kit you have got, and if you buy anything else, buy it to purpose and not because it's cheap. Be clear about what you are trying to achieve. For planets, if you are not satisfied with the eyeball view, forget EAA and go for planetary imaging. You can dabble in this with your current 4SE and a suitable planetary video camera. Your 4SE with its built in flip mirror is actually designed for this. (If I quoted the cost new of my current planetary imaging setup you would probably feel ill ?). For deep-space EAA, I have had promising results with a 102mm f5 refractor, ASI120MC camera and SLT GoTo mount for near-live EAA. The f5 gives usefully wide field with the small (planetary) sensor and the GoTo mount is needed to find the targets blind. The results on galaxies did not look exciting, but when I compared some of the images with visual view from a 203mm SCT I was amazed. You could use your 4SE mount which would accept an alternative small refractor like the Startravel. Do read the EAA/ EVAA threads and see what other people are doing. Note that for faint extended objects you want a 'fast' telescope rather than a Maksutov or SCT.

I hate to bring bad news, but why do you want to buy this particular telescope and mount? (I assume you mean the basic EQ-5 without drives or GoTo). I have the equivalent telescope and mount in my collection, and I hardly ever use it. Why? Because, compared with the other telescopes and mounts in my collection, it is almost unusable. This combination is much marketed, but consider the following: With the equatorial mount, the eyepiece can get into some awkward and even inaccessible positions. (With the legs fully extended, the eyepiece can be as much as 7 feet (2.2 metres) above the ground. ) Equatorial mounts have two uses: for long exposure astrophotography (for which this combination (EQ-5 + 200mm reflector)) is not suited as the telescope is too heavy for the mount if photography is intended); and for tracking objects in the absence of a GoTo mount. If the mount does not have GoTo that also restricts its usefulness IMHO - it is far easier to locate faint and non-obvious objects with a GoTo mount. If you intend visual observation only, it is better (as a beginner) to avoid the complication of an equatorial mount and consider a different mount, e.g. a Dobsonian. As for your eyepiece question, wait till you have bought and used a telescope, and then order the eyepieces(s) you feel will be most useful. With the telescope cited you will probably want a range of eyepieces + barlow to give various magnifications.

Amazing detail. I thought from my own inferior images that the South Polar Cap was shrinking - thanks for confirming that.