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Geoff Lister

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Everything posted by Geoff Lister

  1. If I take the optical tube from my Celestron Astromaster 130 (the 'telescope' bit) and attach it to the mount and tripod from my Skywatcher Skymax 127, I have the equivalent to the NEXTAR 130p. The Celestron NEXSTAR and the Skywatcher Synscan handset software are different, but have very similar functions and features. As mentioned above, an 8" Dob. will gather more light from dim objects, but, a computerised system will give you full GoTo; and I found it helped me to start learning the night sky. The other, often overlooked, benefit of GoTo, is tracking - the 'scope keeps pointing at the target, so you do not have to make frequent pointing adjustments, and can swap eyepieces without having to find the target again. You mention the "glass of red", I liked the Skymax system so much that I bought a second one for my (former) holiday home in France. This is it set up with a modified webcam replacing the eyepiece. My Skyliner 10" Dob. has the same Synscan system, so I have the benefits of both larger aperture and full GoTo/tracking - but at a price! A system wit a 5" mirror and full GoTo/tracking is a good place to start your voyage of discovery. Geoff
  2. I think that the responses, above, are far more informative than anything that I could add.
  3. It's difficult to anticipate the effects of stray magnetic fields on a compass - Elmer Sperry developed a gyrocompass system for use on ships, so avoiding this problem. I bought several, cheap, compasses on eBay, and, by holding one, and, moving it around the assembled mount, found the best position where the OTA had least effect. I don't think it is worthwhile spending lots of money on a compass, provided the needle swings freely around on it's pivot. Geoff
  4. This is how I did it with my 127mm Mak. I marked the positions for "normal" (25mm eyepiece), binoviewer (with 2 eyepieces), and my D3200 DSLR. I used tippex and a coat of varnish, and sat the OTA on a piece of 40mm dishwasher waste pipe to act as the fulcrum. On my other OTAs, I have just marked the balance point for use with a typical eyepiece. It speeds up assembly, and cuts down strain on the mounts' gear trains. Geoff
  5. The OTAs of my Skymax 127mm Mak and Heritage 130p fit well on each other's mounts; but with the Mak's eyepiece at the rear, and the 130p's at the top, the mount has to be set lower for comfortable use of the 130p (or standing for the 130p and seated for the Mak). With care, I can swap the two OTAs, on the Skymax mount (with tripod legs almost fully retracted), and still retain reasonable GoTo alignment. Geoff
  6. I have the V1 Virtuoso mount, and sometimes use it with the Synscan handset from my Skyliner. I measured the current consumption of my various mounts, (at +12V), and this will give you an idea. With a minimum voltage requirement of 7.5V, a set of 8 NiMH rechargeables, with 2500mAh capacity, should give you a good evenings observing before they drop below 1.0V (almost flat) each. My Synscan handsets require a minimum of 11V, so I tend to use batteries of 10, rather than 8, NiMH cells. This is a range of 12V power supplies that I use. Geoff
  7. "Budget" and "Baader Zoom" do not tend to fit well together. I like my 8-24mm Baader zoom, and, together with its companion 2.25x Barlow, gives me a 4mm to 24mm eyepiece range. I also have a "budget" 8-24mm zoom - it cost about a quarter of the price of the Baader, but is not far behind in performance. With my 250PX flextube Skyliner, I tend to start with my 32mm Plossl, and then go to the zoom. When I bought my Skymax 127, probably a couple of decades ago, the Skywatcher/Celestron importer for the UK, OVL, were offering a discount on the, cased, eyepiece and filter set. I am a glasses wearer, and the 6mm & 8mm Plossl eyepieces do not have enough eye relief, but the 13mm, 17mm & 32mm Plossls are fine. I also have the Svbony "ultrawide" (about 68 degrees) 6, 9, 15, & 20mm eyepice set, and these are worth considering. But, as "Spile" suggests, give your existing eyepieces a proper evaluation, and then consider filling the gaps. Geoff
  8. Is it possible that, during the GoTo slew, the extra current drawn caused the voltage at the handset to drop, even briefly, and the handset software to "forget" its position. This can be a problem with the Synscan handsets, that need at least +11V for reliable operation. The Starsense hardware may not be quite so voltage-sensitive, but it is worth a check. My Celestron SkyProdigy mount, with its built-in camera, and dedicated handset, takes about 250mA more (for the camera) than the equivalent Skywatcher Skymax mount and Synscan handset. Geoff
  9. +1 for Copper Slip. WD40, or "Water Displacement, 40th Formula" is not a long-term lubricant, but works as a releasing agent and temporary surface protection. I have had my trusty tube of Copper Slip for several decades, and I would not expect to fit any steel-to-steel fixings without a thin film. I have also used it, in bulk, when replacing steam loco boiler washout plugs - without it, the high-pressure water and thermal cycling, can make them difficult to remove. Geoff
  10. The usual advice, is to use the 'scope with its 25mm and 10mm eyepieces, and then decide. The 10mm is probably the weak link. I can only advise, based on my experience, but this would be my order of purchase. 1 A 32mm Plossl eyepiece - the Mak gives a narrow field of view, but this will give you the widest view with a 1.25" eyepiece. 2 A x2 Barlow - this will give you the equivalent of 16mm and 12.5mm eyepieces, using the 32mm Plossl and the supplied 25mm. 3 An 8-24mm zoom eyepiece - the Skywatcher and Celestron offerings at about £80 work for me, without breaking the bank. 4 A suitable power supply - the Az-GTi mount is not thirsty, but 8-off alkaline AA cells will probably not last very long. This is what I use:- The 6V packs were "borrowed" from my radio-controlled model sailing yachts, and the plug-top supply came from an obsolete ethernet switch (the white, heavy-duty, bell flex shows up well in the dark), but there are plenty of 1.5 or 2A equivalents, often sold for powering the 12V LED flexible, stick-on, lighting strips. Geoff
  11. +1 for the 127. The AZ-GTI mount is an improved version of my Skymax mount - mine does not have the manual clutches. The Synscan GoTo is very effective, but I found that I had to do a bit of homework on my bright stars to speed up alignment. Quite often, I would select the suggested second alignment star, only to find that it was behind a tree, roof, or fence. I spent a couple of hours with the excellent "Stellarium" program on my PC, and, by adjusting date and time, for dusk at the middle of each month of the year, I was able to produce a table of 14 bright stars, visible from my garden's patio, and select a few of these, with rough compass direction and altitude angle. I did the same for an hour before dawn, but that table is rarely used! By selecting a pair of alignment stars with about 90 degrees difference in alignment, the Synscan software does a good job of compensating for any errors in leveling the tripod. Once the bug takes hold, it is possible to use different OTAs on each other's mounts, although there may be some limitations on maximum altitude angle. If I want a wider angle view, I can (carefully) remove the 127 Mak OTA and fit the Newtoian OTA from my Heritage 130P, or my Star Travel 120mm refractor, without having to repeat alignment. Geoff
  12. I did the opposite with my Skyliner Dob base. There is no adjustment for the feet. I line-up one foot with the 'down' side of a bubble level (an addition to the base), and slide a wedge under the foot until the bubble is central.
  13. Most tripods have an adjustable clamp on each leg, so the bubble level on the Virtuoso mount will show when the leg lengths are correct.
  14. Sorry, I can't remember. It was probably about a decade ago.
  15. This is a photo of my Heritage 130P. The mount base is similar to that of the Virtuoso. The plastic table/stool and glass-top table allow easy 360 degree access. Geoff
  16. My Skymax and Skyliner mounts have the Synscan handset, and, as mentioned by John, above, need at least +11V. As Alan also mentions, the 8-cell battery holders are a poor way of connecting to the individual cells - 16 contact points of dubious quality. I found the best way to provide portable power, was to use a series pair of 5-cell, 6V, 2600mAh NiMH packs, borrowed from radio-controlled model sailing yachts. These packs are designed to work with the peak demands of servo motors, have spot-welded connections, and are terminated with decent connectors, and, despite my best efforts at sailing, somtimes get a bit wet (no problem with astronomy). I also found a 10-cell battery holder, so, if necessary, can use NiCd or NiMH cells. A 3S LiPo battery will also work, but discharges to 9V at its rated capacity, so not quite so useful; but a buck-boost power converter may well solve that problem. I measured the current consumption of my mounts:- It's the auto-slew to the 2nd alignment star, that will use both axes at max rate, and highlight any poor contact resistance. Geoff
  17. I have used several different 12V, 1.5 or 2A, plug-top mains supplies with my various Skywatcher and Celestron mounts. These supplies came from old USB powered hubs, desk-top external hard drives, and ones supplied with LED stick-on lighting strips. Geoff
  18. I use a plastic patio stool/table, or, a slightly larger glass-topped patio table. This gives an idea of some possible additions to the mount Geoff
  19. I have the 127mm Mak., and a Heritage 130P. Both are excellent. My 127 came as part of a Skymax setup, with a Synscan GoTo mount and handset. This is my Skymax setup, in a format similar to that of the Travelscope 70. Total weight about 11kg, with a few eyepieces and a couple of sets of batteries. I liked it so much, that I bought a second one for my holiday home (house sold just before COVID hit) in France. This is the setup with a modified webcam in place of the eyepiece - fine for Jupiter, Saturn and the Moon. The Mak. with its longer focal length, really benefits from a tracking mount, and preferrably, full GoTo. This is my preferred portable battery supply; the packs were "borrowed" from my radio-controlled model sailing yachts. The contact resistance is much lower than individual cells in spring-loaded plastic holders. This is my Heritage 130P, and Virtuoso 90mm Mak. The tracking on the Virtuoso mount is good for longer, high magnification, views without having to touch the mount, and for daytime solar viewing with a solar-film filter over the front. The Virtuoso mount will, with care, just about handle the 130P and 127 Mak OTAs; as long as I limit the maximum slewing rate; and, as a bonus, I can plug-in my Synscan handset, for full GoTo. Geoff
  20. I have the same Skymax mount, and my Skyliner Dob mount also has the same Nyloc nut. The difference between a slack axis and a tight one is a fraction of a turn of the nut. I have adjusted the clamping force, so that there is no slip in normal operation, but that it will slip if part of the OTA touches other parts of the mount or tripod. Geoff
  21. I have a 2" 56mm Plossl that I use with my 10" Dob, but it only gets very occasional use. All my other eyepieces and cameras are 1.25", so to use a 2", I have to remove the 1.25" adaptor from the end of the focus draw-tube and replace it with the 2" one, then reverse the process for all the others. I have also found that I need a short extension tube to achieve focus, so adding to a bulky, and heavy, extension at the front of the tube. To compensate for the extra weight, I had to add a balance weight at the primary mirror end. I haven't done the sums, but I would have thought a 32mm 52 1.25 Plossl would do a similar job, in a more user-friendly, and cheaper, package. I normally start my sessions with mine. Geoff
  22. +1 for the 32mm Plossl and 7-21mm zoom. I tend to start a session with my 32mm, and then the zoom. The zoom is particularly useful, with Jupiter & Saturn, for getting the best compromise between magnification and clarity of view. Geoff
  23. Hello Brad, and welcome to SGL. I have the same system, with the older, V3, Synscan handset. Several years ago, I had problems with the azimuth axis control; not exactly your problem, but it would not align or give fine positional control. The problem was inside the azimuth gearbox cover. There is a motor control board, with several ribbon cable connectors going to the motor and the 2 encoders (motor position and, if moved manually, axis position). One of the ribbon connectors was partly disconnected from its pins. It was difficult to see, as it was on the underside of the board, and the ribbon cables have very little slack. I managed to re-seat the connector, (using manual dexterity and a dental mirror!), and the mount has behaved perfectly since. From your description, it looks as though the motor position control loop is not getting the encoder feedback. I have used my mount with 1.5A and 2A plug-top supplies, but the Synscan system is likely to give problems if the internal voltage drops below about 11V when doing a maximum-rate slew in both axes simultaneously, usually during the alignment auto-slew to the 2nd alignment star. This voltage drop is often caused by poor power-connector contact or thin/long (higher resistance) power leads. Geoff
  24. +1 for the standard focuser with the Lacerta dual-speed upgrade. I fitted the upgrade to my Skyliner 250PX and found it easy to fit, and a pleasure to use. Geoff
  25. Hello Chris, welcome to the forum. I have the Skymax 127mm Mak, and I tend to start my observing sessions with my 32mm Plossl. Next, I tend to use a 8-24mm zoom, to get the best magnification/visual clarity compromise, particularly when viewing Jupiter and Saturn. My version came with a 6x30 straight-through finderscope, and I replaced it with a 6x30 RACI version - much easier when aligning on high-altitude stars. Geoff
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