Cosmic Geoff

I have never found the SCT focal ratio to be a problem. I use eyepieces ranging from 8 to 32mm. Remember that with a powered mount it will be easier to keep objects in field.

I doubt that a 102mm refractor would significantly outperform your present scope. If you are prepared to spend up to £1300, why not consider an 8" SCT? This would give a useful increase in aperture over your present scope, and be shorter and lighter than an 8" Dob, and in several of the standard packages would also have GoTo. The Celestron SCTs are now quite expensive new, but there are lots of them out there and you should be able to find a used one at half the price of a new one. This should be no problem if your budget is in fact £1300.

The Dell Vostro is just an example. (It happens to be the model I am using for imaging). It's just a fairly up to date type with SSD instead of HDD, and USB3 ports, and consumes far less power than my older Vostro. There are lots of laptops on Ebay as dealers buy business clearouts and sell them on. Any computer with serial ports belongs in a science museum. 🙂 Astro camera - look up the details of the ZWO cameras in my signature.

Here the Startravel 102 or 120 can be bought as an OTA. Apparently the AZ3 mount is one to avoid. The chromatic aberration is more visible in some circumstances than others - obvious when viewing the edge of the Moon, not noticeable on images of galaxies. Overall it is not enough of an issue to make me yearn for an ED or APO telescope.

I had this 16/17 error twice with my Celestron SLT mount. Briefly, it means that the handset is not seeing the mount electronics. In my case the cause was that the mount firmware had become corrupted and required to be re-loaded. The procedure for this requires a laptop, cabling with USB to serial converter that connects to the handset, and download of various firmware and utilities. (see nexstarsite.com for guidance) Also worth checking that the handset cable is firmly pushed into the (partly hidden) socket in the mount. And that you have an adequate power supply and that the plug of any external power supply is making proper contact. (Poor connection here is a known issue and it causes assorted problems). I recommend that you do not try using wifi until you have restored the outfit to proper operation with the handset. If the mount firmware has failed, trying wifi will be a total failure. Also note that if you want to connect the mount or handset to a PC or laptop, you need to look up on nextarsite.com how this is done - it will not connect if you just plug in cables, and you might even cause damage.

What is the lifespan of a LiFePO4 Battery? | RELiON (relionbattery.com) This claims that a LIFePo battery will last for thousands of cycles, and last 10x longer than a lead-acid. (If charged every 10 days it should in theory last longer than the mount and telescope. 🙂).

I use a 102mm f5 Startravel for EAA and find that it works fairly well for giving enhanced views with a FOV of about half a degree. I bought a 50mm finder/guider with the idea of using it for plate-solve & re-sync alongside my visual telescopes, but I found it just didn't work unless aimed at a dense starfield like the Pleiades. A 127mm Mak should work for planetary (including imaging).

The jump starters are relatively cheap, (often cheaper than a lead-acid 'astro power pack'), do the job and can also be used for starting your car, inflating tyres, and emergency lighting (depending on model). They all seem to have a cigar lighter type output, and I doubt it matters much what model you buy for primarily astro use. I also have a Celestron LiFePo power pack, which was relatively expensive but said to be longer lasting than lead-acid batteries. It is light in weight for its capacity and also works well as an emergency light (good for working under car, or slug-hunting). The output could be as much as 16v when freshly charged, but this has not been a problem in two or more years of use with three of my mounts. The output will drop slightly if you don't use it immediately after charging, and will also drop a little under load. The 5v USB output may also be of use to some. I would recommend either of the above for the O.P's rig. No need to buy anything exotic,, suspiciously cheap or any extra converters.

Rather than answer this point by point, I would just say that when I first thought of buying my 127mm Mak SLT, I was thinking that I could fit an astro camera to it and view and control remotely... All this is more difficult in practice than it may seem to the uninitiated. The SLT mount is not what I'd choose for a remote-controlled outfit. I do have a setup that is capable of achieving the degree of GoTo pointing accuracy you would require for finding objects by remote control, but it relies on plate-solving (q.v.) The interfaces do involve RS-232 ports, but nobody uses computers incorporating these physical ports these days, and the relevant control port on my EQ-5 Synscan mount is physically a USB port, but still requires a special driver for reasons too tedious to describe here. And it is controlled via Windows 10. Any recent laptop will probably suffice. The challenge is that Goto Mounts have a limited aiming accuracy, and astro cameras have a practical field of view that is often rather small. Providing an astro camera that combines a large field of view (for finding things) with high resolution (for viewing fine planetary detail) could prove expensive. The view of a planet as seen via a live-view setup on a laptop screen will be familiar to planetary imagers - the view is surprisingly bad! The detailed views produced by planetary imagers involve 'lucky imaging' (q.v.) via processing a video of several thousand images, and substantial post-processing. If this has not put you off, I suggest that you acquire a useful laptop, e.g. a used Dell Vostro Windows 10 business laptop a few years old, and an inexpensive astro camera. and try setting this up with one of your telescopes (without any remote control or remote viewing) . The difficulties of your project will then become apparent. 🙄

What are you trying to do with the boiling water? This will have no effect whatsoever on steel or aluminum sheet. As suggested above, once you remove all the breakable stuff, steel sheet can be straightened out by panel beating. Inevitably this may flake off some paint, and you will not get the shape perfectly restored. Bending the metal in the opposite direction with that knob might help to straighten it. Steel will soften if heated red-hot, but there is no need to go to that extreme. 😁

A new 8" Classic Cassegrain or a used C8 OTA (plenty of them around) would be within your budget.

1. You can use colour (OSC) or mono, or mono with colour filter wheel - it's up to you. 2. Most of the ZWO cameras have a 2" body, a detachable 1.25" nosepiece, and threads that match the common adaptors. 3. What is a comma corrector? 4. Depends on the scope focal length, and the pixel size in your camera. 5. I'd suggest a small pixel size. You do not need a large chip size. A lot of people used an ASI224MC but now a ASI462MC seems favored, with even newer models coming. You will also need an ADC (atmospheric dispersion corrector) for best results, especially if the planet is low in the sky. You could start by trying the ASI120MM - the ASI120MC wasn't a bad camera, and you won't need to guide for planetary imaging. 🙂

I have a 15mm, 8mm and a 8-24mm zoom that I use with my C8 SE. I also have a 32mm Plossl (rarely used). What eyepieces to get is a topic that will run and run...

What's your budget for the planetary imaging scope? There are lots of options. You need aperture, though in this country there could be diminishing returns in sizes beyond a C9.25, it seems, because of poor seeing. A 127mm would be underwhelming, but you could get the larger Mac, a Classic Cassegrain or a SCT (new or used). For planetary imaging, you could choose anything that the HEQ5 would physically support for visual use. A Newtonian would be cheap but could prove awkward to use, partly because of the restricted focal range.

The ASI120MM will work, but the results will be mono (OK for the Moon). I used an ASI224MC for a couple of years. I now use an ASI462MC which works well. It has a smaller pixel size than some other cameras (+less need for a Barlow). There are probably even newer cameras worth considering. You will need a UV/IR cut filter for this camera, and you may as well buy an IR-band pass filter as well for IR imaging. You will also need an ADC (atmosphere dispersion corrector) for best results. I use an alt-azimuth fork mounted SCT.

Removing the OTA from a CPC800 is not something you want to do every day. If you want an 8" SCT, the CPC800 is a better mounted scope than the C8 SE (which has the same OTA) but the outfit is much heavier. I still think you should get a separate mount for your solar scope. Why not use the mount of the C4 SE? It should take the weight and you can have the scopes on and off the mount in seconds. I have had a 102mm f5 Startravel on my SLT mount.

I have found that dew settles preferentially on upward facing surfaces. I always use a dew shield and find this is adequate 99% of the time. More condensation-prone locations may require adopting heated solutions in addition.

Out of interest I connected up my ASI120MC camera after a session on Jupiter with the ASI462MC. The processed results are not much different between the cameras (though the seeing was bad and none of the final images look sharp). Found that with Sharpcap 4 the frame rate was a lot slower with the 120MC and the exposure time a lot more, and that the gain for the ASI120MC is variable, with the maximum being 100. I took a couple of videos with the IR filter and the ASO462MC, which clearly showed up a transiting moon (only its shadow could be seen on the normal shots.) With the ASI462MC, 5000 frame videos gave a notably better result than 2000 frames. (Finger trouble there).

You would need a second dovetail bar and some tube rings. I think you are under-estimating the weight of the 500x102mm (I have one). If I were you, I would provide the solar scope with its own mount. A CPC800 is heavy - I have one and it takes me half an hour to heave it out of its storage, attach the fragile bits and get it ready for observing. If you give the solar scope its own mount you could deploy it far quicker. If you carry out your scheme, be sure not to uncap the CPC800 OTA or its finder while solar observing, otherwise you will melt something.

I'm not familiar with the mount, but you can probably use it as a manual just by leaving the clutches slackened off. It may also be possible to reconfigure it as an alt-az if you reconfigure it for 0 deg or 90 deg latitude. Personally I don't believe in this 'learn the sky' philosophy much. This isn't the 19th century. Electronics rule.

Just to add my few words of advice. Don't get hung up on the chromatic aberration in achromatic scopes. Many people were perfectly happy with their long focal ratio achromatic refractors before the ED and APO scopes were introduced. Also note that visible chromatic aberration does not = Ruins Your Evening. Even with the f5 achromats, the chromatic aberration, while definitely present, is more obvious on some targets (e.g. the edge of the Moon) than on others (e.g galaxies and nebulae) I have a classic brass 70mm refractor with a very long focal ratio which shows no chromatic aberration at all. Beware of budget telescopes that are 'too cheap'. At one point I bought a supermarket refractor which, while in most respects excellent value, had an objective lens which (as I eventually realised) was not good enough. I might have tried sourcing an upgrade, but there was no way of getting the objective lens off without using a saw. At one point I had both a narrow-field (f12.5) and a wide-field telescope in the 4" & 5" aperture range. I used the narrow-field instrument far more, and made little use of the 102mm f5 achromat till I discovered I could image with it. The Startravel 102mm f5 achromat appears to be a short version of Sky-watcher's Evostar, and for the price is a well-made instrument with the focuser, dew-shield, tube etc all made of metal. It makes a useful budget imaging scope but is not much good for viewing fine detail on planets etc.

I'm not familiar with the scope and mount, but suspect the mount drive is purely intended to ease visual observing. If you read up on what people use for serious astro imaging, you will see the difference...

There are various things you can check in the daylight before binning the mount, e.g. has anything happened to jam the movement? Is the azimuth motor actually running? Are there any fault messages on the handset? Will moving the connectors clear a bad connection? (Note that the altitude and azimuth motor/gear units appear identical and could be swapped over as a test.) Most of the small GoTo mounts you can buy separately come from Skywatcher, and having used a Nexstar you may not like the Synscan operating system much. 🙄 If you do buy another mount, beware the effect of not having the support on the same side of the scope as with the SLT.

The raw image always looks bad on screen. If you can make out any detail it often means it's a good night.

No idea how bad your result was. ASI462MC and C8 works well for me. If you are trying for the best result, you need an ADC even at moderate altitudes, as the dispersion is significant compared with the fine detail you are trying to resolve. And yes, the ADC has the same effect on stars. Moon - irrelevant.