Geoff Lister

10 hours ago, Cjg said:

Not sure how good the importers of Skywatcher are

Several of my Skywatcher items were shipped directly by Optical Vision Ltd. I believe that they are the main (only?) authorised UK importer. I have not had any problems with my Skywatcher or Celestron 'scopes, so I do not have any after-sales experience.

Geoff

The composite photo, below, shows how much they have in common.

and a range of interchangeable mounts and OTAs

Geoff

I made a small adaptor so that I can use my Virtuoso mount on my Skymax's tripod. I screwed a "Terry" clip to the side of the Virtuoso mount, to keep the adaptor handy.

4 minutes ago, happy-kat said:

The interesting thing to me is one of my manuals covering the eq mode shows the mount on what looks like the star adventure wedge. 

Yes, mine does too. My Virtuoso mount has a female 3/8" - 16 UNC tripod thread, but most of my photographic tripods (cameras and dovetail bars) use 1/4" - 20 UNC. A quick web search indicates that the Star Adventurer wedge seems to have a 3/8" female thread on the tripod end, but I could not find thread details for the male, camera/OTA, end.

Geoff

3 hours ago, happy-kat said:

The newer edition of the manual no longer talks about the EQ mode boot up option when I last downloaded it.

I have 3 versions of the manual, 2 PDFs downloaded about a year ago, and the paper version supplied with my 'scope. Each is different. My paper version "Instruction Manual MiniDob Mount" has the cover sheet and then internal pages labelled "1" to "16" + back sheet. One PDF, 7656KB, with front page title "Instruction Manual Skywatcher Virtuoso Multi-purpose Mount #S11750" seems to be aimed at the USA market, has an additional solar filter accessory, and a Celestron USA contact address; it has 13 pages. The other PDF, 368KB, same title as my paper version, but with different text, graphics and paragraph structure, and with front sheet, then pages labelled "1" to "10" (no back sheet).

My paper copy, on page 11, has the following section entitled "Equatorial Tracking Mode for Celestial Body"

1. Attach the MiniDOB onto an elevation degree adjustable tripod according to the figure below:- (figure shows a tripod with an adjustable inclined plane)

2. Users in Northern Hemisphere aim the tripod at North (Users in Southern Hemisphere aim the tripod at South). Adjust the elevation angle and ensure it equals the local geographical latitude value. (No advice for those living on the equator).

3. Set the Latitude setting for the MiniDOB according to the 'Quick Guide' (pg 3). This is a bit confusing, as there is no 'Quick Guide' on page 3, but pages 1 & 2 have a 'Quick guide' for North and South hemispheres, respectively, and section 3 of each shows setting local latitude for N hemisphere and "0" for S hemisphere.

4. Press '5' first then 'turn on power', it should now be under the RA equatorial longitude tracking mode.

I assume that, in stage 4, holding down button "5" at power-up, turns off the altitude axis tracking component. Worth a try at some point.

Geoff

The virtuoso mount uses the standard Celestron/Skywatcher/Vixen dovetail clamp. The basic mechanics are designed around a light-weight, compact, OTA. I have used mine with my 127mm Mak (3.5kg instead of the 90mm @ under 2kg), and the OTA from my truss-tubed 130mm Newtonian Heritage 130P, but I try to avoid doing maximum-speed slews. The Virtuoso mount has adequate clearance for the 90mm OTA, but will not work with a balanced 127mm or 130mm at high altitude angles. A long-tube refractor would also have similar restrictions, and would impose greater torsion loads during acceleration. Like many pieces of equipment, you only know the true limits when something breaks .

Geoff

I love mine. As mentioned, above, a great grab-and-go. The C90 Mak. has a relatively narrow field of view, and is not so capable as my Skymax 127mm Mak when looking for the faint fuzzies. The mount has a much higher slew rate than my others, and I have used it with the Skymax's Synscan handset for full GoTo. The mount is very stable, and I tend to use it on a glass-topped round patio table, about 60cm diameter and 60cm high, on my paved patio. The manual indicates that, although it is an Az/Alt Dobsonian mount, it can also be used on a wedge, to give it the photo-friendly EQ mount capabilities (on my "to do" list).

Geoff

The Micrel MIC2171 is a 2.5A switch-mode power controller. The data sheet has several sample circuits, showing 470uF capacitors as the main smoothing capacitors. Without adequate capacitance, voltage ripple may well affect the circuitry downstream of the regulator.

Geoff

The 70mm OTA of the Travelscope is let down by its tripod. I found it difficult to use as a low-magnification terrestrial spotting 'scope, and almost impossible to get a stellar object to stay in the FOV as soon as I let go of the altitude handle. The 130ps is available on various mounts, all of them a vast improvement on the Travelscope's tripod, and, as a bonus, they will also work with the 70mm OTA's dovetail plate.

Geoff

As a beginner, and for visual astronomy, I would suggest that you avoid telescopes with an equatorial mount (the "eq2" bit in the description). I found the Astromaster 130EQ-MD, in my signature, difficult to use when I started, and I have not used it much since. An Azimuth/Altitude mount is more intuitive, either the Dobsonian type (as on the Heritage 130p) or on a tripod.

The EQ2 publicity photos show the Newtonian tube uppermost, with substantial balance weights downwards, and the eyepiece on the side facing you. If you then rotate the assembly, so that the tube moves towards you, and the weights away from you, the eyepiece is pointing down, so you have to release the 2 clamping rings and turn the tube to get the eyepiece horizontal again. With an Az/Alt mount, the tube does not rotate as you scan left/right/up/down.

This will give you an idea of the different sorts of mount https://en.wikipedia.org/wiki/Telescope_mount   then https://en.wikipedia.org/wiki/Dobsonian_telescope  & https://en.wikipedia.org/wiki/Altazimuth_mount .

Geoff

+1 for the Heritage 130p Flextube (look at the 5-star reviews associated with Louis D's link), & 1 or more better eyepieces, including a x2 Barlow https://www.firstlightoptics.com/barlow-eyepieces/celestron-2x-universal-125-barlow.html for better views of the planets.

If you want a tracking system, to keep the object in the field of view of the eyepiece, then I find my Heritage 90 Virtuoso works well https://www.firstlightoptics.com/heritage/skywatcher-heritage-90-virtuoso.html .

I tend to use my 32mm Plossl eyepiece first to look at an object, and then use the smaller ones for more magnification https://www.firstlightoptics.com/celestron-eyepieces/celestron-omni-plossl-eyepiece.html.

Geoff

To get an idea of the construction of the manual 250PX, have a look at:-

https://storage.googleapis.com/skywatcher-canada/upfiles/en_download_caty01316546523.pdf

and the version with the Synscan motors and handset, at:-

https://storage.googleapis.com/skywatcher-canada/upfiles/en_download_caty01335568752.pdf

I always store, and transport, the OTA and base separately. The base has a diameter of (from memory) about 53cm, and you develop a "wide knee waddle" style of walking to get you through doorways and up/down steps.

I have the Synscan version, and at the end of a session, I select the "Park Scope" "Home" function in the "Utility" menu, and this places the OTA horizontal and pointing North. To separate the OTA & base, I release the locking bolt and lift the OTA straight-up for about a foot. On assembly, it is a matter of seconds, to lower the OTA into the mount, and tighten the locking bolt.

I have about a 10 yard/metre walk between where I store the Skyliner and my observing position, and I recon it takes me about 90 seconds longer to set up the OTA (including extending the three truss rods) and base, than it does to set up the tripod, mount and OTA of my Skymax 127 Mak.

Geoff

I think that I will play safe, and view the Sun through my ST120 refractor, using the solar film-covered centre section of its objective lens cover. We are in serious trouble, if I need the full light-gathering properties of the 250PX to look at our local star.

On ‎13‎/‎11‎/‎2017 at 23:01, cletrac1922 said:

Also with the dust cover, take off the small cover, and attached some Baader on underside of dust cover, and you can also observe the sun

I may well try this, but the main cover has a narrow lip to grip the tube end, so I am concerned that a gust of wind could enter the large gap and push the cap off. I guess, a couple of bungee cords would give added protection.

With a solid tube design, OK; but with the open design, would stray bright indirect sunlight entering the gap, and reflected off the underside of the dust-cap, ruin the contrast?

Geoff

On ‎14‎/‎11‎/‎2017 at 14:35, Andy250px said:

I can never set my eyepieces all the way into the focuser, I always need to pull them out a few mm just to get focus. 

The focuser does seem to have a short travel range (just measured at 41mm). I have not had any problems with my 1.25" eyepieces, but I too found that with the 2" eyepiece adaptor, and my one 2" eyepiece, a Meade 56mm Super Plossl, I had to pull it out about 0.75" to get focus. I resolved this by buying a 30mm-long, 2" eyepiece extension tube. If I remember correctly, from one of the other threads, it may help to use the collimation screws to move the primary mirror rearwards a few millimetres.

Geoff

My 250PX is like the one in John's photo, above, but with the Synscan GOTO. I tend to set up mine on my patio, with power ON, well before dusk, do a "brightest star" alignment as soon as I can spot the first bright star (e.g. Vega, Arcturus or Altair), go in for tea and a warm-up, and come out again, perhaps an hour later, with the second alignment star still close to the centre of the eyepiece.

When not in use, the OTA (retracted and vertical) and base are kept in an unheated garage, with the rigid cover and "shower cap" in place and the whole OTA covered in an old bed-sheet. This seems to keep the mirrors clear of contamination.

Geoff

It impressed me so much that I bought a second one for my holiday home in France. An excellent compromise between aperture and portability.

I have had one of these car starter/air compressor packs for many years. I leave it plugged in to a timer socket, and it gets topped-up for about 30 minutes a day. If I am not expecting to use my car for a period, I leave the pack connected across the car battery and that ensures that the car battery is also kept healthy. The charging regulator circuit in the pack turns off the charge current (about 0.5A) when the top-up is adequate. I get a reliable start even if the car has not been used for over a month.

Geoff