thoughts on a high quality portable mount?

[buzz]

I bought the Avalon and await the return of the iOptron. You might be surprised but I would like to keep both. My original post was for a lightweight system. The Avalon, fitted with a William Optics Star71 / EOS cannot be balanced. The counterweight bar on its own is too heavy. There is still a place for a super light-weight mount that balances lightweight equipment.

 

[Davey-T]

Having acquired a 10Micron GM1000 HPS I've set about the iEQ45 to try and improve it's performance.

Purchased the HP worm and fitting new sealed bearings and precision ground shaft.

I have previously found the build to be very slapdash and simply by careful assembly reduced the RA slewing power consumption from around 1.5 amp to under 1 amp, the problem is the worm mesh is un-adjustable once assembled as the motor prevents access to the bolts.

I've come to the conclusion that with any "budget" mount it's a matter of luck whether it works as advertised out of the box and most of them will need a bit of fettling to achieve their best performance, which is all very well as long as you're capable of, and enjoy a bit of DIY. 

BTW when I first had the iEQ45 it had a couple of problems that it went back to have fixed and when it returned the first time it obviously hadn't been touched, just returned as was, however the next visit got it fixed OK.

Dave

 

[sloz1664]

3 hours ago, buzz said:

I bought the Avalon and await the return of the iOptron. You might be surprised but I would like to keep both. My original post was for a lightweight system. The Avalon, fitted with a William Optics Star71 / EOS cannot be balanced. The counterweight bar on its own is too heavy. There is still a place for a super light-weight mount that balances lightweight equipment.

 

Hi Buzz,

I had the same issue with my Avalon Linear / WO star 71 / Atik 460 combo. I purchased a 3Kg counterweight and manufactured a "half length" counterweight bar from 30mm diameter stainless steel bar. Thankfully it's nicely balanced now.

Steve

[buzz]

For info - I'm using the ASCOM driver through the handset, rather than EQMOD. I have used EQMOD in the past with an EQ6 but it was a love / hate thing.

With my Paramount I use Dimension 4 NTP program to set accurate time in TSX and noticed that Synscan does not have an inbuilt clock. I needed to send the PC clock to the Avalaon. (I'm not using GPS) I noted that the API supported reading and writing UTC to Synscan and after a discussion with the ASCOM driver author, Chris Rowland, he very kindly provided me a script that sends the clock over. It is a VBS, with options for daylight saving or not.

set c = CreateObject("ASCOM.Utilities.Chooser")

c.DeviceType="Telescope"

id = c.Choose("")

set scope = CreateObject(id)

scope.Connected = true

 

MsgBox "UTCDate is " & scope.UTCDate

' use next line for daylight saving only

scope.UTCDate = Now - 1.0/24.0

'use next line for normal time only

scope.UTCDate = Now

MsgBox "UTCDate set to " & scope.UTCDate

 

[buzz]

I knew that guiding the Avalon was going to be interesting....  I just didn't know quite how much.  Currently I'm using Lodestar/ST4/PHD2 with  0 min move, 1sec exposure and 100% aggression. and lowest guide rate (0.125x). Scope was William Optics FLT98, with the lodestar securely in the eyepiece holder. 

My guiding last night resembled a wounded fish!

I tried a few variations 0.5 sec to 10 sec, changed aggression down to 50%. DEC seems OK when there is drift but the RA is proving a challenge. ( have not yet tried pulseguiding through the Skywatcher ASCOM driver or using guiding through EQMOD)

This is only my first light with the setup so I expect a learning curve. I would be really interested in other users suggestions and typical performance.

[update]

I think I nailed the guiding. I conceptualized a ball suspended from a piece of elastic and thought about how I would raise and lower the ball without vertical oscillation.  The trick was to find a scheme that introduces the smallest moves, as gently as possible, without leaving behind the residual PE. The PE without guiding measured about +/-5" with some quite quick swings, so longer 10 second exposure times had less seeing noise but potentially big corrections and oscillations. I needed to first remove all other causes of tracking errors - so PA'd with the PoleMaster beforehand this time and supported the wiring bundle to minimize any drag.

The combination of Skywatcher ASCOM pulse guiding and less aggressive inertial moves reduced the RMS to under 0.5". Very short exposures were a bit too reactive to seeing noise. Somewhere in the middle, 1-3 second, a little hysteresis, 0.75 or higher aggression, low guide rate and good PA seemed to work well. I disabled DEC compensation as that introduces more sensitivity to seeing noise at high DEC. The hysteresis / aggression is a balance; rapid guiding with high aggression helps if it has some hysteresis to filter the noise.  My DEC RMS was less than 0.1" 

[buzz]

iOptron #3 came back.  PE slightly better but not great. Pk-pk values change significantly with RA and I cannot get PEC to work with either ST4/ASCOM (with latest firmware). Not good.

Will have to use the Avalon for lightweight gear - so I'm getting another shorter counterweight bar being made up in aluminium for balancing and their lightweight aluminium tripod to reduce the overall package weight.

[buzz]

Useful information for iOptron users:

Another user (CEM60) on the user group suggested the PEC failure could be due to interference from a dew heater. I was using a (filtered) high frequency PWM dewheater and fully regulated DC power supplies. When I turned the dewheater off, PEC worked.  All my other electronics and cameras have no issue, including the Avalon mount, using exactly the same interfacing kit. I used to design RF circuits and the first thing I would try, if the mount was not in warranty, is put shielding inside the plastic covers and a few more decoupling components near the connectors.

I thought that was it, as my Pk-Pk reduced from 60" to 7"  but it then refused to execute the ASCOM guide pulse commands that I had used 10 minutes earlier to calibrate PHD2 or learn PEC.  I tried repeating the whole exercise using ST4 but ran into other issues:

With the original and replacement mount I noted that after a slew, the mount would sometimes track, but at the wrong rate. (Slew command issued from TSX via ASCOM). In both cases it was immediately following a PHD2 guider calibration using ST4 (one was with a Lodestar X2, the other with a Superstar).  The 2-second PHD2 exposures were streaks!  A second slew fixed it and the mount tracked at sidereal rate. When it happened the first time, I pulled out the ST4 cable but it still kept going. I use PHD2 with ST4 or Pulseguide on other mounts without apparent issue. Bizarre.

I'm using the latest firmware and maybe something slipped up. I cannot roll it back as iOptron only show the latest version.