Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

sgl_imaging_challenge_banner_android_vs_ios_winners.thumb.jpg.803608cf7eedd5cfb31eedc3e3f357e9.jpg

Geoff Lister

Members
  • Content Count

    627
  • Joined

  • Last visited

Community Reputation

368 Excellent

About Geoff Lister

  • Rank
    Proto Star

Profile Information

  • Gender
    Male
  • Interests
    Railways (full-size and model), radio-controlled model boats, and astronomy
  • Location
    North Somerset, UK
  1. The OTA has the standard dovetail plate, running the full length of the main tube. The OTA fits comfortably on my Skymax mount, for full Goto, for a wider FOV than the 127mm Mak. The focus assembly on the Heritage 130 is at the top, when mounted on the original Dob. mount, or equivalent where the dovetail clamp is to the right of the OTA. If mounted on an EQ mount, or photographic tripod, the eyepiece position moves to the right-hand side and places more strain on the focuser's thread. There would be a significant risk of a camera falling to the ground. Geoff
  2. This gives an idea of the current consumption. When tracking, the Virtuoso mount takes little extra power if viewing close to Polaris, and increases towards the celestial equator. The high consumption is when slewing at maximum rate. Geoff
  3. If you want a system that is air-transportable between Geneva, Scotland and London, then it is worth considering the Skymax Synscan 127 GoTo system. The Mak. design is very robust. I have one in the UK, and a second one that I have transported across France. Neither of them have required any collimation adjustment. The whole setup weighs about 11kg. Geoff
  4. I have used my Virtuoso mount with my 127mm Mak., and the 130mm Newtonian from my Heritage 130p. Both seem OK as long as you limit the max slew rate to 4 (not 5), and avoid targets at high altitudes. Geoff
  5. I have 2 Skymax 127 systems; one in the UK, and one in France. Both came with the 6x30 straight-through finder, but I replaced the UK one with the RACI equivalent, as shown in John's photo. The RACI one is much easier to use for high-altitude alignment stars. Last night, I was using my French system, and Vega (at about 70 degrees altitude) as the first alignment star, and I had to get on hands and knees to use the straight-through finder. French concrete is uncomfortable on the knees . Saturn is a better target when viewed from Bristol's twin city, Bordeaux, particularly after a glass, or two, of the local wine. The "redundant" straight-through finder is now on my Astromaster 130 OTA, as the Astromaster's original RDF is useless. Geoff
  6. Hi Gordon, and welcome to the SGL. I have this system, and it is a very good table-top Dobsonian mount. It does have a 3/8" - 16 UNC internal thread in the central section of the base, but would need a thread adaptor if you use a normal photographic tripod. However, it is much more stable if used on a small table. I use mine on a 60cm diameter glass-top patio table. It is much more stable than my tripod-mounted systems. To get the widest views, I use a 32mm Plossl eyepiece. The MCT optical tube also works well with my Celestron 8-24 mm zoom. This gives me adjustable magnification; and thus select the optimum magnification / image clarity compromise for the best view, particularly for the planets.
  7. As Geoff Barnes mentioned above, Goto gives you tracking; almost essential at high manifestations. I have struggled to find Uranus and Neptune with manual mounts, but had no problems with my Synscan mounts. With tracking, you can try different eyepiece, and the target stays centred; with a manual mount, the target drifts off. I often use my 127mm Mak. OTA on my Virtuoso mount. I point the finder roughly at Polaris, power-up, and then use the direction buttons or manual movements & re-tighten clutches, and I have decent tracking without the need for full Goto alignment. If I want a wider view, I use the OTA from my Heritage 130. Geoff
  8. I stick them in the oven after the Sunday roast/Apple crumble has been removed. I read somewhere that if you use a microwave, when most of the water has been driven off, there is no "load" for the microwave energy and it puts more strain on the magnetron. Geoff
  9. My 250PX mount does not have adjustable feet. I mounted a decent bubble level on the base. To level it, I turn the bottom of the base so that the bubble is towards the direction between 2 of the feet, and insert a metal wedge under the third foot to centre the bubble. I used a metal wedge, because it was handy, but a wooden one would work fine. Once level, I rotate the upper part of the base to point north, extend and fit the tube, and power up. Yes, this is a problem, but the first star alignment will sort out any compass error. The important bit is the level mount. Geoff
  10. Hello Peter, thank you for the feedback. I found it difficult to get a sharp focus, with the poor LCD contrast and the atmospheric distortion adding ripples to the edge of the disk - Jupiter is so much easier, particularly with its convenient Galilean moons. I have added your suggested sites to my browser "favourites". There was a small hole in the clouds, so I tried the SS60 on my Virtuoso mount. The SS60 fits neatly in place of the 90mm Mak. With the mount on the patio table, the EP was at a convenient height for seated viewing. With the Virtuoso mount and alternative SS60/90 Mak., this makes a very handy grab-and-go battery/mains combination (the Virtuoso mount only takes about 40 to 80mA when tracking). Needless to say, as soon as I had the combination tracking the sun, the big black clouds arrived, and I had just enough time to take this photo before the deluge. Geoff
  11. I have used solar film fitted in the lens covers of my 90 and 120mm refractors, but realised that if I wanted more detail in the view, I had to get a dedicated Ha instrument. Last week, I received a parcel from FLO, (very speedy service, and with the usual "May Contain Clouds" sticker), containing a Daystar Solar Scout 60. The sticker was correct, but last Sunday (6th) the sky was largely cloud-free. The package contained a plug-top 5V 1.5A USB A, PSU, but with input pins designed for USA mains sockets. I found an adaptor in my "bits box", but I also tried the 5V 2A supply that came with my Android tablet, and a USB battery pack with 2.1A output; both seemed to work. The battery pack fitted in the little satchel that came with my Skymax Mak., and hung from the mount's eyepiece-holder tray. I have a plug-in mains power meter, and I found that, whilst the unit was warming up, the input power to the supply peaked close to 8W, so the 1.5A supply may be close to current-limit at times. I also used a strap to support the power lead at the 'scope end - the lead has thick cable, and wanted to avoid the "tail wags dog" effect. I borrowed the diagonal from my ST120 and started with a Celestron "Omni" 32mm Plossl EP. The adjustment knob has click positions, with "hourly" intervals from 1 o'clock to 11 o'clock, so I started at 6 o'clock. The view was clear and bright, but no obvious detail, except a minor ripple running round the disk (of similar amplitude and frequency to that round the Moon when I used another OTA as the Sun was setting below roof height). I tried each of the adjustment settings, but could not see any obvious detail on the disk (there was much more activity from my eye's floaters). I also tried my 8-24mm zooms (Celestron and Baader Hyperion Mk4); both gave reasonable performance, but no obvious improvement in detail. During the last half-hour of sunlight, I replaced the EP with my (colour) GPCAM + 0.5 focal reducer, and took a few stills. I normally use the camera and laptop combination at night, and found that it was difficult to get a clear view of the image on the LCD - the strong sunlight washed out most of the contrast. This is a section of what was probably the best. I found that by tilting the laptop's display slightly I could see a little more detail in the disc, but nothing spectacular. I need to spend more time imaging, to find the optimum SS60 tuning position and camera settings. A day without clouds and frequent showers would be useful. I will probably get a case, similar to the one featured earlier in this post. Question:- I noticed that, as the unit was going through its 10-minute warm-up, the LED flickered between amber and green many times before remaining green, and then, when established, showed flickers of lower brightness green. Is this normal? Geoff
  12. I have used solar film fitted in the lens covers of my 90 and 120mm refractors, but realised that if I wanted more detail in the view, I had to get a dedicated Ha instrument. Last week, I received a parcel from FLO, (very speedy service, and with the usual "May Contain Clouds" sticker), containing a Daystar Solar Scout 60. The sticker was correct, but last Sunday (6th) the sky was largely cloud-free. The package contained a plug-top 5V 1.5A USB A, PSU, but with input pins designed for USA mains sockets. I found an adaptor in my "bits box", but I also tried the 5V 2A supply that came with my Android tablet, and a USB battery pack with 2.1A output; both seemed to work. I have a plug-in mains power meter, and I found that, whilst the unit was warming up, the input power to the supply peaked close to 8W, so the 1.5A supply may be close to current-limit at times. I borrowed the diagonal from my ST120 and started with a Celestron "Omni" 32mm Plossl EP. The adjustment knob has click positions, with "hourly" intervals from 1 o'clock to 11 o'clock, so I started at 6 o'clock. The view was clear and bright, but no obvious detail, except a minor ripple running round the disk (of similar amplitude and frequency to that round the Moon when I used another OTA as the Sun was setting below roof height). I tried each of the adjustment settings, but could not see any obvious detail on the disk (there was much more activity from my eye's floaters). During the last half-hour of sunlight, I replaced the EP with my (colour) GPCAM + 0.5 focal reducer, and took a few stills. I normally use the camera and laptop combination at night, and found that it was difficult to get a clear view of the image on the LCD - the strong sunlight washed out most of the contrast. This is a section of what was probably the best. I found that by tilting the laptop's display slightly I could see a little more detail in the disc, but nothing spectacular. I need to spend more time imaging, to find the optimum SS60 tuning position and camera settings. A day without clouds and frequent showers would be useful . Geoff
  13. Yes. This is my understanding of the process:- With a perfectly level mount, and the altitude (elevation) set at (say) 45 degrees, a full 360 degree azimuth rotation of the mount should describe a circle at exactly 45 degrees to the horizon. However, if the mount was tilted slightly (say) towards the south-east, that circle would fall to below 45 degrees in a south-easterly direction, gently rising to above 45 degrees in a north-westerly direction. At power-up, the Az/Alt mount does not know where it is pointing, so the handset sets its pointing software registers to zero; equating to the OTA level and pointing to the North Pole. It works out any new position by counting pulses from the motor encoders on the 2 axes, multiplied by the gearbox ratios. When you select your first alignment star, the handset calculates the correct azimuth and altitude of that star, based on the time, date, and location that you have entered. When you centre the first star, the software can now put the "correct" Az & Alt values in its registers. When you select the second star, the mount performs an automatic slew to point the OTA towards the location in space where that star "should" be if the mount was perfectly level. The software then records the difference between its "guess" and the true position, when you have centred the star and hit "enter". It uses these differences to make a best estimate of the mount's tilt. If the 2 stars have an azimuth difference of about 90 degrees, and an altitude difference of at least 30 degrees, this makes the sums easier, and the "estimate" more accurate. It is much easier to get the mount level with a spirit level, than it is to get the OTA pointing to true (not magnetic) North. With the mount level, the calculations are likely to be more accurate, to give you a better GoTo position. It also means that the "guess" for the second star is more accurate, and so easier and quicker to find and centre. If your mount comes with a small bubble-level, it is worth checking this against a good spirit level, as I have found that the one on one of my mounts was a bit off. I marked the proper bubble position with a small blob of Tipp-ex, and that seemed to speed up alignment for future sessions. I am sure that there are other forum members who have a more detailed knowledge of the alignment process, but I hope the above explanation makes sense. I use Az/Alt Goto, but I would assume that a 3-star alignment helps to eliminate the extra polar alignment errors.
  14. I loop the cable through one of the side handles. If the cable gets tight, the cable pulls on the shoe box, holding my plug-top supply & mains extension lead end; this slides on my patio quite well. Geoff
  15. Your photo looks like my Skymax 127mm mount, which has the Synscan V3 handset. This handset works with my Virtuoso 90 (tracking mount with built-in buttons similar to your handset), so I would expect the electrical and signal interface to be common for tracking and GoTo. The difference is the "intelligence" in the GoTo handset. The 150mm tube, I assume it's the Newtonian, is longer than my 127mm Mak. At max slewing rates, this will place more strain on the gears as the OTA accelerates and stops. Geoff
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.