Geoff Lister

I tried my Virtuoso's Az/Alt Dob. mount on a wedge, and by setting the Alt to the North Celestial Pole, i.e. 90 degrees, I was able to get EQ tracking on the Az axis, with no (obvious) Alt movement. So, with Az Synscan, and a wedge, and the latitude setting at 90 deg. N, it should be possible to get a reasonable EQ operation. Synscan's alignment correction should remove most of the remaining setup errors. Note to self:- I should try this with my Virtuoso's wedge between the Skymax mount and tripod. Geoff

This table shows the current consumption I measured on my various mounts. So, for the 10" Dob. spending most of the time tracking, an average consumption of 700mA gives 0.7Ah per hour, or 5 hours for a 50% discharge on a 7Ah battery. Geoff

Hello Mark, I have a couple of mounts with Synscan handsets. As I understand it, the WiFi version has similar facilities and user interface. The star database is limited; the named stars tend to be only the brightest ones in each constellation, and limited to "named". This may get you to the epsilon or zeta stars, but unlikely to stretch to mu or nu. However, if I want to find the Andromeda Galaxy, I go for the "M" option (button 4 on my handset) and enter "31". Geoff

The Synscan system gives you GoTo, but it also gives you accurate tracking. You can use the manual buttons to select an area of sky, and then change eyepieces to get the desired view, in the knowledge that the view will not have drifted away during the change. Geoff

I have the 250mm Skyliner truss-tube version with Synscan GoTo. The mount has a pair of heavy-duty gearboxes, (I think they use all spur gears, but there may be a worm somewhere in the train), and the handset has the option to calibrate the drive to remove backlash. There are dual encoders on each axis, so you can move the mount manually, with suitable fixed clutch friction, and the mount still knows where it is pointing, for excellent tracking. I often do "Brightest Star" alignment at dusk, and the tracking will keep an object near the centre of a 32mm eyepiece whilst I go in for tea and wait for the sky to get fully dark. You only need to be able to see 1 star to do a manual slew to the first star, and when centred, the mount performs an automatic slew to close-to the second star, usually well within the field-of-view of my 32mm eyepiece. Geoff

I went the other way, and set my Virtuoso to 90 degrees before mounting it on my wedge. With normal tracking, the azimuth axis moved (at about 15 degrees/hour), and the altitude pointer remained at a fixed position on the scale. My reasoning was that, at the North Pole, celestial objects will remain at roughly the same azimuth (Dec.) angle as the Earth rotates. Geoff

+1 for Stellarium. If , like me, you have 'blind' areas behind houses, trees and fences, Stellarium will help you identify the bits of sky that are available, from dusk and onwards during the night. Once you have selected a few visible constellations, do a web search for DSOs in that constellation, or just zoom-in on the Stellarium view. In the winter months, what you can see at 7pm is very different from 11pm. A planisphere is fine, but Stellarium adds planets, comets and the Moon. Geoff

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