Cosmic Geoff

To answer your last question, there has been some discussion about this on the forum, and in particular I remember a graph which shows the altitudes at transit for the next few years - Mars & Jupiter improve rapidly, Saturn more slowly. An ADC (atmospheric dispersion corrector) will counteract some of the malign effects of the low altitude. A C11 will probably do fine, and you've got it now ... some suggest that a C9.25 is the sweet spot for lousy UK conditions, but some members here post fine pics taken with C14's. Seeing is key, and if you are in a rural location with vegetation under the light path you may have better luck than those in urban locations. As for your mount, it is perfectly possible to planet image with an Alt-az GoTo, (avoiding the hassle of polar alignment) and since you have the option, I suggest that you accurately level your tripod, set the mount in alt-az mode, and solar system align it on the planet you want to image. That process ought to be quick and painless. The only downside of using guided alt-az for this is that the image may be tilted (which may not bother you at all) You may get less drift with a two-star align. I presume that an AZEQ6 GT can do a two-star align in AZ mode - I don't have one so I wouldn't know.

I got out just in time with my CPC800 setup + ASI224MC. The seeing low down was bad, and got worse as the session progressed. With a zoom eyepiece (about x200) I could not make out any moon or shadow. On the screen Jupiter at times looked like an egg in a blender - the worst seeing I have encountered here. I packed up wondering why I had bothered to upgrade the mount and camera for this year.😕 Reviewing the image videos this morning I find that the first processed images show the shadow clearly, and also the moon emerging as a pimple on the planet's limb. Most of the following ones show the progress of moon and shadow, and the last at near midnight shows a GRS creeping into view.

An ADC is adjustable to compensate for the low altitude dispersion, and in practice will reduce it to an un-noticeable level. That's the whole point of using it. One is still imaging through a long atmospheric path, however.

Rather depends on whether the OP particularly wants a Dob, or whether he might like a C8 SCT, which has a different focal ratio and narrower fields. The C8 OTA is very light and you can put it on any manual mount you like if you don't want one of the Celestron GoTo mounts. If you go for the popular C8 SE that is the most portable of the GoTo variants and quick to set up (carry the whole thing outside). I did hanker after an Evolution which has a better mount. The OP won't want the CPC800 which is very heavy and designed with imaging in mind.

An image of Jupiter taken late evening, 27 June. Not as good as some other people's efforts, but one of my best Jupiter images this year. The planet was low (around 15 deg) and the seeing was not great. CPC800, ASI224MC, ADC, captured in Sharpcap, processed in Registax6. Best 20% of 5000 frames IIRC. One of the images here is a random raw frame, to show what I had to work with. Io should be visible on left in the processed image.

An image of Jupiter taken early morning, 16 June. Not as good as some other people's efforts, but the planet was low (around 15 deg) and the seeing was not great. CPC800, ASI224MC, ADC, captured in Sharpcap, processed in Registax6. Best 15% of 7000 frames IIRC. One of the images here is a random raw frame, to show what I had to work with. Ganymede should be visible on left in the processed image. GRS coming into view on left.

Below is a single-shot or 1-frame image of Jupiter, taken through an 8" SCT fitted with an atmospheric dispersion corrector. Altitude of the planet was ~14 to 15 degrees. This is what you are likely to see if you take a look at the planet visually. Dire, isn't it? An experienced observer with patience would see more detail in moments of better 'seeing', especially if observing from a better location. The blur is caused by observing through an unstable atmospheric soup. In a vacuum, an 8" telescope would give a much clearer image. The frame is from a 5000-frame video which when digitally processed discloses far more detail than shown here.

There is no shortage of advice for planetary imaging inline. Maybe you are overcomplicating your processing. I suggest capturing using Sharpcap (or your choice), saving the file as a .ser file. This avoids the step of converting it to colour in PIPP. While capturing, use the histogram in Sharpcap (or equivalent) to set the exposure level to around 70% max of peak white. Import the .ser file into Registax and process it, using around 20% of the best frames. If the image quality is very poor, you will not be able to pull any detail out of it.

When imaging low planets, I found that the images had colour fringes, which could be taken out to a degree by aligning the red & blue separately in processing. The dispersion amounts to a lot more than the nominal resolution of the telescope. I read that an ADC would do it better, and indeed it does. No contest.

It sounds like the telescope is simply not in focus. Try focusing it through the whole range of the focus mechanism. A star should look like a point of light. If that doesn't work, check that various bits such as extension tubes, 2" to 1.25" adapter etc are positioned as they should be, and you don't have too much extension or not enough. One you get the feel of how the telescope responds, sorting out this sort of thing should become much easier.

Sorry to be discouraging, but I think the problem is a combination of excessive expectations, poor telescope quality and atmospheric conditions. If focus is achievable on the Moon, it will also be achievable on Jupiter and reveal a small glowing blob as in Michael8554's simulation. The view of Jupiter + moons is distinctive, and you cam focus on the moons, which should look like white dots in a small telescope (or with poor seeing and low altitude, wobbling white blobs). We had a discussion a while ago on how much focusing on the Moon differed from focusing at infinity, and the conclusion was that the difference was too small to be detectable or significant.

'Perfect' isn't attainable. With this telescope, you need to think about upgrading the eyepieces as the kit ones almost certainly are not that great. You will also need a x2 barlow lens to extend the range of the eyepieces in the direction of higher magnification. Which eyepieces you buy and how much you spend is up to you, but note that if this telescope has a f5 focal ratio, some eyepiece designs will not be suitable. Also get an external power supply insteqd of relying on the internal batteries - it does not much matter what, so long as it delivers the right voltage for a sensible length of time.

Why not contact some 2nd hand astro equipment dealers and see what they can do for you? One might take the unwanted kit off your hands and supply a (used) C8 SE within days. You could take a hit on value but the saving in hassle might be worth it.

Wearing my mechanical engineer hat, I'd say that the linked slotted dovetail bar looks like it should do the job. Alternatively, any dovetail bar could be made to serve with a couple of suitable holes drilled and countersunk. You could fit a bar the same length as the tube, with some packing near the screws and thin double sided sticky tape to prevent movement between the bar ends and the OTA end caps. I assume that you do not want to drill the OTA. Alternatively, get this: https://www.firstlightoptics.com/dovetails-saddles-clamps/skywatcher-l-bracket-dovetail.html Its use should be self-explanatory. See the customer reviews.

These look good, lots of detail. CPC1100 looks like right tool for the job. 🙂

Jupiter is looking particularly bland lately - with a small telescope one might be able to make out just one cloud belt. I have never acquired the knack of seeing much planetary detail - tried various scopes and eyepieces. Eventually having several scopes and a spirit of 'what's to lose' I tried planetary imaging and pretty soon had an image of Jupiter taken through the 127mm Mak that was far better than anything I had seen visually. I then had a season imaging with a C8 and ASI 120MC. I also found that my binoviewer + Skywatcher x2 Barlow lens worked surprisingly well for planetary viewing on Mars- possibly because as well as using two eyes it cut down the glare at each eye by more than half. For visual use, the C8 SE is the best planetary scope in my collection, seeing permitting.

I had to look up what a GIAZ mount was. This is clearly a visual mount, but the 150PDS and Evostar 80 ED appear to be imaging scopes which would require a totally different mount for imaging. Can you explain? If you want a complement to the Mak, a f5 Newtonian would offer widefield views of starclusters and nebulae, but will not be a plus for planets unless it's a lot bigger than the 127mm Mak. I don't think that a smaller refractor would be an interesting visual alternative to the 127mm Mak.

Why are you using Sharpcap 2.1? I use Sharpcap 3.1 (which I assume is a later version) with this camera and I am not having a problem. And yes, there probably is a setting to turn on on-screen debayering.

And as a footnote, a setup optimised for planetary imaging would be radically different and just as expensive. Bought new, my CPC800 (C8 SCT + heavy duty fork mount), ASI224MC planetary video camera, and ADC would cost over £2000. One doesn't have to use a CPC800, as a SCT on a substantial equatorial mount is usually preferred, but that is no cheaper.

The dew shield. Before buying a load of non-essential accessories, wait till you have tried using the scope, which if you live in the UK may be in a few weeks' time. ☹️ I anticipate that you will want a couple of higher powered eyepieces (cue long discussion thread...) something like a 15mm and a 8mm. How much to spend? depends on how much you like spending money. It's not a demanding scope - I have found that Celestron Omni Plossls work well enough. I see that it comes with a couple of eyepieces but I'd not expect them to be very good - the higher powered kit eyepieces I got with my scopes were generally poor. And some sort of proper external power supply - it doesn't matter what, so long as it reliably delivers the correct voltage for a sensible length of time. A lot of people use engine starters (from Halfords etc) which do the same as a Celestron power tank, but are cheaper (and start your car, inflate tyres, or whatever). Don't bother with Barlow lenses - it has a long Fl already.

The message of the video is pretty clear. ☹️ Also, did you notice how much the scope bounces around on its mount when he touches it toward the end of the video?

Beware of trying to cut corners with mounts - in my experience a lot of them are annoyingly wobbly even with the recommended OTA atop them. Wobbly: EQ-2, Celestron SLT. Celestron SE 6/8 - not great but okay for visual with a short 5.5 Kg OTA. Not wobbly: AZ-4, EQ-5, CPC800 mount & tripod. I bought a vintage 70mm refractor for a modest price and then found that owing to its length and weight the minimum mount was an AZ-4 or EQ-5 , either one costing far more than the scope did.

It's an entry level telescope - if you read the small print you will see you can't collimate it. And to work the wifi mount you need to provide the "handset". If the mount can get GPS from the tablet or phone that might be advantageous.

It is also quite light and easy to carry, - a quote from a customer review of the 150mm Skyliner Dobsonian. You need to confirm the actual weight of your scope + base. Are you perhaps confusing the Kg and lbs weight figures? The weight should equate to about 27 -29 lbs. If it is 16kg and that is too heavy to carry, then we can try to suggest something lighter. Actually I can believe that 16 Kg is likely to be too heavy to carry in one lump up several flights of stairs. Perhaps the solution is to carry it in two sections - tube and base? The C6 SE at around 13.5Kg total is one of the lightest outfits you will find without going below 6" aperture.

What mount are you currently using? You don't say but 27kg kit weight seems a lot. If you want GoTo, this is just possible for £400 if you choose one of the smaller & more portable outfits. Also consider a Celestron C6 SE (used). This is a 6" SCT with GoTo and the tube is a lot smaller and lighter than the equivalent Newtonian. If you are normally fit, you will be able to pick up the whole thing including mount and tripod, and carry it through a doorway. It also comes apart fairly easily into 2 or 3 sub-assemblies. You can do planetary astrophotography with this (though the mount is not ideal). Also consider a 6" Dobsonian (cheap and low-tech and not excessively heavy). This could be carried in 2 parts - tube and mount. Observing nebulae (galaxies) from an urban site will not work well. If you have a lot of light pollution it is best to concentrate on small bright objects (e.g. planets, double stars etc) Be aware that serious astrophotography requires heavy and expensive kit and lots of cables and accessories - not the kind of thing you will enjoy taking upstairs and assembling on a rooftop.