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Despite trying for over a year we have been unable to get our telescope’s Paramount ME set up accurately.
If anyone is willing to come and assist we would be eternally grateful. We are based in Milton Keynes.
Sheridan WilliamsSheridan Williams
First problem is I cannot set up the mount accurately N/S and altitude. Having done that approximately and aligning an object and synching, it will not slew back to it later.
Another way I tried was to slew to an object, then physically adjust the mount in RA and Dec. This slews back to the original object but fails to slew to a new object.Sheridan Williams
How far out is the mount N/S alignment? Iron piers can be a pain because of their impact on a compass. Also, have you set the approximate latitude on the mount properly ie within a degree or two?
So, you power up. You connect TSX successfully and you tell TSX to go home. Does it do that, making the bing bong noises it uses when it finds Home AND afterwards, are the lights on the mount the colours the manual says they should be (off hand, I don’t remember what they should be for an ME)?
So, if you Go Home and then tell TSX to do sidereal tracking and try to image a star through the scope do you get untrailed star like images?
Can I assume you have changed your location in TSX to the mount’s current location / height – Google or similar will easily give you 3 decimal place accuracy – height accuracy doesn’t have to be perfect. Also, how is your computer time being maintained? If a network is available Sync the time in Windows Settings or use the Meinberg server software. If not available then a £9 USB GPS dongle will do the job if used with NMEATIME2 software (cheap licence). Laptops have internal clocks but closing down Windows or not using the laptop for a week or two can -in some cases – lead to a big time difference between the laptop time and the real world.
Further question, do you have the T-Point add on? That would make life much simpler.
Hang on. I just thought. You talked about an ME 2 years ago.
From the forum it looked like the gears were not properly engaged and you might have had trouble with a serial to USB adapter. Is this the same scope?
You mention in that old forum that you were using Sky6. Why? I thought this was a new install and part of the purchase deal for a Paramount is a TSX licence. Why would you use the old code?
The usual way of polar aligning a Paramount is to use Tpoint. After a mapping run it will tell you how far off your alignment is and in what direction. It is generally very quick.
The gear problem was sorted. The system is exactly as we inherited and was working fine. It had Sky 6, so no need to pay to upgrade software. USB adapter checked and working fine.
Sheridan Williams
Latitude set approximately but scale on side only allows 2-3 degrees precision. N/S done with compass and checked roughly with Pole star.
Powers up successfully and goes home, bings & bongs, lights on mount OK. Location set using GPS coordinates, time checked too in software every time scope used.
Set sidereal tracking, slew to an object (doesn’t appear in finder scope) use hand controller to correct. It then stays centred in view in view for viewing session by visitors (15 minutes).
Surely approximate alignment would not need TPoint. The scope is being used for Cub, Guides, Brownies etc who are only viewing for 20 minute sessions.
We have a problem with TPoint in that we need to use objects around the sky which are obscured by buildings and lights (the OU is probably the most light polluting place in MK!) They have also placed building and trees in places that obscure the sky.Sheridan Williams
When I setup my observatory I did the following to align my equatorial mount on the pole.
I started with a rough alignment, which from the sounds of it you have already done. For azimuth, I found out when the Sun would be due south and then aligned the mount shadow by eye. For altitude I used the crude scale on the mount.
I then performed drift polar alignment to get the alignment more precise. This works best with an illuminated reticle eyepiece or digital camera. Depending how accurately you need the alignment, you watch how a star drifts in a couple of different locations on the sky over 1 to 5 minutes. Here are a couple of links to the technique.
https://explorescientific.com/pages/polar-alignment-using-the-drift-method
https://www.skymtn.com/mapug-astronomy/ccdastro/drift-align.htm
In my experience this simple technique works really well. One point to note, it is easy to get mixed up about which direction the mount needs shifting, so I keep a careful watch as to whether my adjustments decrease or increase the speed of the drift. I first used the technique with a portable setup, and after some practice I could get very accurate alignment within 20-30 minutes.
NLO has a Paramount ME that we successfully polar aligned using the polar finder imaging routine in Sharpcap. It is quite an old model kindly donated by the late Kieron McGrath of SCS Astro. Its been very reliable with no problem in slewing to objects.
David
Hello Sheridan,
Can the scope have an imaging camera attached? One way of checking rough polar alignment with an ME is to note the precise time (to, say, a few seconds GMT) when homing completes and the sidereal tracking starts. Then, immediately take an exposure of, say, 60 seconds. If there are plenty of stars on the image upload it to Astrometry.net and it will calculate the precise field centre. For an ME it should home at 0 dec and 2 hours past the meridian at the time you homed it. Of course this is somewhat dependent on nothing going wrong with the homing process (you get the bongs, so that is encouraging) and also the telescope being mounted parallel to the Versaplate…… It also assumes there are no trees or buildings from your site that are over 30 degrees high at an azimuth to the SSW…. Astrometry.net will instantly tell you if the field centre is far from zero degrees Dec. The sidereal time from the observatory at the time tracking started, minus two hours, should tie up with the R.A. calculated by Astrometry.net.
It’s a simple test that should give you a rough idea how far off the polar alignment of the mount might be.
Martin
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