Geoff Lister

I have had my SW Skyliner 250PX Synscan GoTo for several years, and have no regrets. Geoff

Well... perhaps not the 127SLT, but these are some current measurements that I made on similar mounts. The Skymax 127 is probably the closest combined setup, but the Skyprodigy and Cosmos give an idea of consumption with different peripherals. These are some of my external 12V power sources. I tend to use the plug-top supply in the garden, and for portable use, usually the 6V 2600mAh packs, borrowed from radio-controlled model sailing yachts. Geoff

I use Synscan's "Brightest Star" alignment on my Az/Alt Skymax and Skyliner mounts. This gives me 2-star or planet + 2-star alignment. I found that the Synscan star suggestions, particularly for the 2nd star, were behind houses, fences or trees. So, I spent some time with Stellarium, and produced a table of 14 bright stars, visible from my garden, and, setting time and date for dusk (bright stars only visible to naked eye) at the middle of each month of the year, chose 3, 4, or 5 with sensible azimuth and elevation separation and noted their rough compass direction (N, NW, W etc.) and altitude. I repeated the process for 1 hour before dawn - not much use except around winter. Currently, if I power up, with the OTA horizontal and facing north, I only need to be able to see Jupiter and the automatic slew for the 2 stars (mid-July using Vega & Arcturus) gets them in the finder, or, quite often, in the FOV of a 32mm EP. It should be possible to do something similar for an EQ mount. Geoff

+1 for the 127mm Mak. This is my Skywatcher Skymax 127, with Synscan GoTo handset, in a portable form. With 2 sets of batteries, and a few eyepieces, the whole lot weighs about 11kg. My Cosmos 90 has essentially the same mount, but uses WiFi and an App. on my tablet. However, when looking through the eyepiece, I find the "real" buttons on the Synscan handset much easier to use, than the "virtual" ones on the tablet's touchscreen. I liked the Skymax so much, that I bought a second one for my holiday home in France. Geoff

Many thanks for posting the results of your search. I have not had any problems with the firmware on my Virtuoso mount, but it is always useful to have this in reserve. Geoff

My Cosmos 90gt is essentially the same, but with a different exterior paint job. I (very, very, occasionally) use mine with my Samsung Android tablet, but much prefer the handsets with my (mechanically equivalent) Skymax and Skyprodigy mounts. I found that the tablet would revert to my home hub, leaving the mount in an uncontrollable slew, so I added power "kill" switch to the mount. I also found that, whilst looking through the eyepiece, I could not easily locate the virtual up/down/left/right buttons on the tablet's touch-screen - not a problem on the other 2 mounts with real buttons and the tactile feedback on their dedicated handsets. There have also been times, during the SkyPortal alignment failed attempts, when I have disagreed with its conclusions, and been very tempted to do my own re-alignment with my 4-pound lump hammer! At least, the 90mm OTA fits on my other mounts, so all is not lost. Geoff

I have not tried my collapsible Dobs. for solar, but I would expect to need a very good shroud between the two main tube sections. Geoff

With my 10" Dob., I have seen, simultaneously, one of the Galilean Moons and its transit shadow on the surface of Jupiter. To me, the moon seemed close to a point source, and yet its shadow had obvious width. I tend to use the moons to sharpen my focus for viewing Jupiter. A quick check on "Stellarium" currently gives Jupiter's diameter as 44.86 arc-seconds, and Ganymede's as 1.65 arc-seconds. Neptune is 2.32 arc-seconds, and I have seen it as a light blue disc, with adjacent stars as white points. Currently, from the south of England, Jupiter is, at best, just over 15 degrees above the horizon, and I have started to lose contrast on Jupiter's surface features with magnification over x130. The atmospheric disturbance gives a wobble to the view, so everything has additional width. Perhaps I will have a better chance in a few years, when the UK's view of Jupiter improves. Geoff

With my birthday near the middle of October, my "star sign" is Libra, but, running Stellarium in annual steps forward from my day of birth, the Sun has remained close to Spica, well inside Virgo - go figure 🙄. I also ran Stellarium back in time, and there was an obvious jump of Sun/background star position, from the top of the scales in Libra to the bottom of the left foot in Virgo, between 1581 (Julian calendar) and 1582 (Gregorian calendar). Geoff

With my 10" Dob., I have found that Uranus and Neptune are a good blue/green contrast to adjacent "white" stars. Geoff

I have Skywatcher's Synscan GoTo on my Skyliner 10" Dob. and Skymax 5" Mak. I usually align using its "Brightest Star" 2-star alignment feature. I spent some time with the Stellarium program on my PC, altering date and time, to identify the brightest stars likely to be visible from my observing position in my back garden. I produced a table of 18 stars, and for the middle of the month, for each of the 12 months, identified 3, 4, or 5 stars visible at dusk, giving adequate azimuth and altitude separation for good Synscan alignment. The table notes the rough compass direction and altitude (with a single bright star, it is difficult to identify the constellation to which it belongs). Synscan has no idea of natural obstructions, such as houses, fences or trees, so may suggest bright stars hidden behind something; the table helps me to avoid these, particularly for the second alignment star. I produced a similar table for 1 hour before dawn; not of much use, this time of year, but viable for the winter months. Last night, just after 10pm, with a reasonably clear sky, Jupiter was bright towards the south. It was still quite light with only a few stars just visible. My table had identified Vega and Arcturus as good alignment stars for July. I used the brightest star alignment in its 'planet + 2-star' mode, manually pointing at Jupiter, (and checking that it was at the intersection of the finder's cross-hairs) and then stepped through the suggested stars to go, with automatic slew, for Vega, then Arcturus. GoTo alignment and subsequent tracking of Jupiter were spot-on; as it was for Saturn, when it had cleared adjacent trees, at about midnight. Then the clouds rolled in 😠. By performing alignment at dusk, it is much easier to avoid aligning on adjacent, but incorrect, stars. You only need 1 star or planet to be visible to the naked eye for the first, manual, slew; after that, the software gets the next star close to the middle of the finder, and, if you start with the mount levelled, probably visible somewhere in a low-magnification eyepiece, requiring minor adjustment to centre the view. Geoff

I have Synscan on my 10" Dob. I use it mostly for visual, but on odd occasions have used it with my GPCAM and laptop. As I understand it, field rotation is minimum with objects close to the horizon (Jupiter at the moment), and worst at the zenith. I tend to use Sharpcap on the laptop, and have had some reasonable results using the "live stacking" feature and exposures of up to 10 seconds. This way, given reasonable atmospheric conditions, I get a sharper image, and start to see some colours with the fainter fuzzies. Geoff

I have found that, to get the best focus on Jupiter, particularly at its current low altitude, it is best to achieve a sharp (sometimes wobbly) focus on one or more of its moons, and then slew to centre the planet, without touching the focus. Just keep looking, for several minutes, and your brain will start to 'see' more features. It is often better to go for lower magnification to get a sharper image, and let your brain fill in the details. Geoff

The rack-and-pinion driven focuser draw tube on my Astromaster 130 has about 4cm of travel. It is a basic 1.25" unit with no diagonal or 2" to 1.25" converter supplied or required. I have not noticed any problems achieving focus with the 20mm erecting or 10mm normal eyepieces supplied with the kit, or with others, mostly Plossls. I would suggest trying a daytime view of a distant building, tree or hilltop. It should be possible to get a good focus, close to the point that you will need to get a sharp focus on stars. Geoff

I have the Skywatcher Virtuoso 90mm Mak. https://www.firstlightoptics.com/heritage/skywatcher-heritage-90-virtuoso.html It has a Dobsonian mount and the built-in tracking does not consume much power from the batteries. It can be used without power, or for full GoTo, with the handset borrowed from my Skymax 127 Mak. The tracking is very useful, as it keeps the object in view, particularly at the higher magnifications. For the widest views, I use a 32mm Plossl eyepiece. Geoff

Having enjoyed the Synscan GoTo with my Skymax 127mm Mak., I decided to increase my aperture with the Skyliner 250 flex-tube, and the same Synscan control. When stowed, I cover the OTA with an old bed-sheet to keep out dust. The truss tubes extend to very positive end stops, and so the OTA keeps collimation very well. I probably make minor adjustments about every 6 months. The GoTo and tracking are very good, used mainly for visual observing, but with the GPCAM feeding my laptop, running SharpCap and its live stacking mode, seems to compensate for minor field rotation. It gives me a decent depth of colour when viewing DSOs. Geoff

I have the Skywatcher 90mm Mak on the Virtuoso tracking mount. The dovetail plate has two 1/4 - 20 UNC (standard photo tripod) tapped holes near the centre of the middle spine. The balance point, with diagonal and eyepiece, is just behind the rear hole, so it would be a little rear-heavy on a tripod. Geoff

The 5.5mm OD/2.1mm ID jacks usually come with the outer sleeve length options of 10mm & 14mm. I tend to use the 14mm, to ensure that the jack reaches the bottom of the socket, with just a bit of the sleeve visible. Most of my mounts have an added strain relief clamp, near the socket. I pass the lead through the clamp, with a short loop of wire going to the inserted jack. This stops the jack being disturbed by mount rotation. Geoff

This is my Skymax 127mm Mak in portable mode. With a couple of sets of batteries and a few eyepieces, the whole setup weighs about 11kg. Geoff

Most small to medium mounts require a power lead with a 5.5mm OD, 2.1mm ID power jack at the mount end (as shown on each of the power sources in my photo above). It is worth going for the ones with the slightly longer (14mm) outer sleeve, so that the jack makes full contact within the mount's socket. The Skywatcher/Celestron 7Ah power tank is supplied with a lead designed to go between the tank and the mount (have a look at FLO's details on this unit). https://www.firstlightoptics.com/batteries-powerpacks/skywatcher-powertank-7ah.html Geoff

I too, was almost put off astronomy with a Celestron Astromaster 130 EQ-MD, on its equatorial mount, for many of the reasons mentioned above. I then bought the Skywatcher Skymax 127 Mak. with Synscan GOTO, with its Az/Alt tripod mount, and liked it so much that I bought a second one for my holiday home. I sometimes use the Astromaster's 130mm Newtonian OTA on the Skymax mount, if I want a wider field-of-view than I get with the 127mm Mak. When I decided to go for more aperture, I bought the Skywatcher Skyliner 250PX (10" collapsible Dob.) again with the Synscan GOTO built-in. From memory, the base has a diameter of about 53cm, and probably about the same height. The base and OTA are both OK for a short (a few tens of metres) carry, and up or down a few steps - you have to adopt a wide-knee-waddle walking method to avoid hitting your shins on the bottom of the base. Geoff

These are a selection of power sources that I use with my various mounts. Most of the time, I use the plug-top mains supply, but if I want portability, I tend to use the pair of 6V 2600mAh packs borrowed from my radio-controlled model sailing yachts. I have found that the 8/10 cell battery holders tend to give connection problems, often requiring repeated mount alignment sequences. As an idea of current consumption, these are some measurements I made on my mounts. Power bank mAh figures are usually based on the 3.7V internal lithium battery, so, for a 12V output, the "useful" mAh value is about a quarter of the value on the case. Geoff

I'm sorry about the delay in responding, but I have been away for a few days. These two photos show my wedge. The Virtuoso's feet sit against the white blocks, and the clamping bolt, in the left foreground, is a 1/4" - 20 UNC with a converter collar to 3/8" - 16 UNC. The horizontal section has compass and bubble-level, and the bolt head, just in front of the slope, is to attach the base to the tripod of my Skymax 127. The speckled marks on the chipboard are from rain ?. I was able to get the virtuoso to operate in EQ mode, by using the standard Az/Alt setup that would apply at the North Pole (Az calibration set at 90 deg.). Not a masterpiece of design or fancy woodwork, just functional. Geoff

I have obviously looked at larger aperture OTAs, but, the 250PX is very capable, and, as an OAP, is at the top end of comfortable portability from garage to patio. Most of the time, I do visual observing, but if I want a little extra, the GP-CAM and Sharpcap's live stacking work for me. Geoff

Hello Mark, The 250PX is worth the money. However, I tend to use my, smaller, Skymax 127 Mak., with the same Synscan control, probably 5 or 6 times more often than the Skyliner. The Skymax, on its tripod, gives me a better view of low-altitude targets, that are obscured by close-by shrubs and fences when using the lower Skyliner Dob. mount. My garden is reasonably well screened from the surrounding streetlights, but security lights and neighbours upstairs lighting can sometimes be a challenge. If the sky is really clear, and preferably with no Moon, the Skyliner's 4x increase in light gathering lets me push the magnification on the more challenging DSOs (+ Jupiter & Saturn, when available at over 10 degrees altitude in a southerly direction). Geoff