Pegasus NYX-101 Harmonic Mount

I’ve always liked what PegasusAstro have been doing with their astronomy equipment and I already own an original FlatMaster120, UPBv1 and a UPBv2.


Packaging – The mount transport box is (21cm x 34cm x 34cm) which is larger than the AM5 transport box. Weight/Size (6.4 Kg compared to ZWO AM5 5 Kg). The build quality follows the same high quality and blue anodised styling of recent products.

On opening the packaging I found damage to the mount knob indicated a possible rough handling in transit with plastic shrapnel in its plastic bag. This was superficial and did not impact the function or integrity of the mount.

There was no hand-controller supplied in the box but the manual hints that a hand controller can be connected to the ST-4 (EXT) port but no detail on if that is compatible with any existing hand controllers, so for now we have to use the Unity PC application, ASCOM access or the mobile phone application (Android).

The USB2.0 port is better than others I have encountered on other mounts such as iOptron and it grasps the cable securely and does not feel loose or feels like it would just drop off. This is especially useful as I tear down each night so let’s see over time if it maintains the positive connection it has at the moment. I connected the mount USB and power to the UPBv2 sat on top of the scope.

The carbon fibre tripod has no stone bag which can be found on other astro/photography tripods. You could suspend some form of weight from the leg spreader that might help prevent the tripod from tipping over with heavier scopes.

I found the Altitude adjustment a bit loose and takes a bit of getting used to even though the NYX101 has altitude tightening bolts which themselves seem to shift the altitude which again affects polar alignment if you are not careful.

Due to the compact nature of the mount there is no room for a GPS receiver so this function is relied upon either from your phone or by pushing the values from Unity or via Uranus device. If you push from your phone and you have Unity running then Unity will not see the change until you restart Unity.

I like the SW tripod (adapter required) and M12 counterweight compatibility, LX200 protocol support, polemaster placement support. There is a polemaster mounting plate but this is a permanent fixture via screws with no quick release mechanism. However there was a post on Cloudy Nights by PhilippeL on a release adapter he made, CAD link here.



Set your park/home positions and then enter in your location/altitude via Unity/Mobile phone app so that the mount understanding things like horizon limits.

As with other mounts, care needs to be exercised that your scope does not collide with the tripod legs, this is still a risk when using the pier extender with longer length scopes.

Unity Software

I couldn’t find a change history or date on the released Unity Platform on the website so it’s not easy to look back when things happened but you can use this link to check the currently available version. I used version 1.8.1733.15, when upgrading the existing Unity software the update process will remove all older versions including the ASCOM drivers and then install the latest version.

I do seem to lose wireless connection to my house router randomly even though the mount was positioned within 6ft of it. I had setup the router to give the mount a static IP address via DHCP but I don’t know it loses the connection – DHCP lease time is set high.

Firmware Update

When I first looked at configuring the NYX-101 to connect to my house network I had no end of trouble getting a connection. The only way I could achieve a connection was to have both the PC/laptop and mount connect to one of my travel routers which itself was also connected my the house wifi.

I soon worked out that the “Smart Connect” feature of my house wifi router was attempting to connect the ESP32 wireless (2.4GhZ) of the NYX to the 5GhZ band. Once I had put the MAC address of the NYX-101 into the exclude list of the house router 5GhZ band then it would reliably connect to the 2.4GhZ band. From that point onwards everything worked as expected and I could then successfully perform the firmware update to 1.15.

The 1.19 firmware (released the week 13th March 2023) also brought a pleasant surprise of the motor noise being reduced when slewing. This is a welcome change since making any noise in a suburban garden location in the early hours of the morning when people sleep with their windows open is highly undesirable.

Resetting park & home

I actually turned off the mount by accident whilst the mount was pointing somewhere in the sky so it lost its position and didn’t know where park and home was. This is easily rectified by moving the mount via one of the applications to the correct marks and setting the home and park positions again. This issue was mostly solved with a later firmware update where the mount now remembers where it is pointed once power is restored. However on performing a meridian flip (no slew & center) and then instructing the mount to home resulted in the mount not being it’s predefined home location.

Mobile App (Android)

Originally there was only Android11+ support but after raising a support ticket ( to request that the documentation state that the linked app only supported Android 11 I also requested a pre-Android 11 support. This actually appeared pretty quickly on the website so kudos to PegasusAstro for the fast response.

I do suffer regular disconnects from the mount when using the mobile app via the hotspot. I’m not sure why this is as I was sat right next to the mount, could be down to an idle time-out ?

I also see the NYX-101 disconnect from my house wireless router in Unity but could locate no reason why (DHCP lease was valid), I could find no entry in the Unity log files or see no reason on the router. Now this could possibly be either interference from other 2.4GhZ networks or down to the Aluminium casing, would an external aerial resolve this problem ?

There is no way to reconnect to the wireless other than shutting down Unity so as long as you have a USB connection then everything should continue working.

Mount/Altitude Limits & Meridian Flip

To begin with I set the meridian and altitude mount limits in Unity and then test the automated meridian flip using ASCOM simulator for the camera. Regardless would I did the mount would stop 10 degrees because hitting the Meridian. It slowly dawned on me that I had set the meridian limit to -10 which I thought was 10 degrees after the meridian but the value should have been +10 so it was actually stopping 10 minutes before the meridian ……. dooh !

Unity hard limits for Elevation & Meridian

Once I made the change then both NINA and SGPro performed the meridian flip just fine. There is also a switch to enable automatic meridian flip to prevent any potential crashes but I opted to leave this disabled so the mount would just stop tracking but NINA would continue taking new subs in both simple & advanced scheduler.

One item that would really help here in a text box with optional input to set either limits instead of having to grab the slider to see the current setting – I can query/set this in the API but it’s not easy to view and change using the slider method.

Polar Alignment

I used the polemaster software to perform a polar alignment but decided to utilise SharpCap to compare the alignment procedure and difference. Because SharpCap requires the scope to be slewed 90° so the scope weight was now on on horizontal the RA axis dropped causing the mount to shift and results in the PA being 4° off axis.

This would happen regardless even if I tightened up the axis bolts. Talking to another user he suggested at using a counterweight but to me this would negate the mount as a portable mount.


Using the OpenPHD guiding reference document (link), it appears the that the harmonic gears have a period of 430 seconds with a periodic error of +/- 20 arcsecs or less. Two complete periods are required for the Permanent Periodic Error Correction (PPEC) before guiding any improvement will be seen, this is pertinent for the imaging train in use at the time. If you change the imaging target the model will re-initiate the PPEC learning cycle.

The recommendation is to set the guiding interval to 1 – 1.5 seconds and try to be within 30 arcsecs of polar alignment error. I certainly found keeping the FSQ85 setup to around 1.5 seconds resulted in better guiding graphs compared to 3 second intervals.


After initially purchasing the mount I took my NYX-101 along to Astrofest 2023 (UK) for Evans to look at (by prior appointment) as I was not entirely happy with the resonance during slewing. I compared my mount against two other NYX-101 mounts in my astronomy society and it definitely sounded like it had been treated roughly during delivery transit. Although Evans did a great job to investigate the mount during the show, due to the noisy nature of the exhibitor floor it was not obvious that it had been resolved until I was in a quiet environment back at home.

On contacting PegasusAstro I was offered to have the mount picked up by DHL and couriered back to Greece for inspection. The whole process from DHL pickup was professional from picking up to receiving the mount back, the service was excellent and he mount was backed with me 7 days later. The courier communications was good but I received no notes or communication on what was done (board serial number was the same) under I enquired. The most important thing the mount operation was much better and more akin to the other two reference mounts I had listened to; my gratitude to Evans and the team for their patience with me.

It had been reported on various forums that the ZWO ASIAir had suddenly stopped working with the NYX-101 and some heated speculation quickly arose as to the reason why this occurred. ZWO was quick to dispel any conspiracy theories and rightly put their hands up and stated it was a bug in ASIAir software (link) which would be resolved in the 2.1 beta release (you will also need the latest firmware). Kudos should go to ZWO for setting for the story straight and resolving the issue to the benefit of the astro community.

First Light Use

So Dave asked me to come over to the observatory for the evenings of 26th & 27th so I could do a test run on the kit I would be taking to Tenerife later that Summer. At this time the M101 Supernova SN 2023ixf so I decided to image it alongside Dave using his 17inch RDK and Bob’s 24 inch RDK.

Using the QHY Polemaster I noticed that when I rotated the mount for alignment that the chosen calibration star moved away from the rotation circle – is the mount slightly misaligned ?

The guiding document available here were extremely helpful in testing out various settings. Certainly I was seeing some trailing around 3 seconds but that could have been due to the PA issues or balance. I ended up using Predictive PEC and setting the interval to 1 second just to see what would happen. I still noticed large variations every now and then and it was not as smooth as I’d hoped for.

Slewing to a target after plate solving it was clear that the mount had moved outside my FoV at first slew. This was unusual for me as my CEM60/NEQ6 first slews were always in the FoV, this issue may be related to an situation observed by Chris Woodhouse and can be rectified by following his forum post.

Chris asked me to confirm his experience of overshoot when slewing in the DEC axis causing the target not to be in resulted field of view. Chris had raised a support ticket for this issue and PegasusAstro were investigating.

Closing Thoughts

The NYX-101 is more expensive that the competing ZWO AM5 but the NYX-101 offers more weight carrying capacity (20 Kg versus 13 Kg without counterweights) and compatibility with those already own QHY Polemaster, SW NEQ6 or similar tripods.

The direct open API (REST) via Unity or access via ASCOM Alpaca allows me to query components and it’s easy to script up web status pages quite easily.

If you only ever plan to use light imaging equipment and are already invested into the ZWO eco system then the AM5 might make more sense but if you wanted to use other vendors equipment then for me ZWO is a closed ecosystem with limited flexibility.

If using USB3 cables for any equipment such as CCD/CMOS cameras then it is wise to invest in a high quality shielded cable as USB3 tends to have issues in the presence of 2.4GhZ. I used 5Ghz wireless from my Mele Quieter3c mini PC to avoid this problem but I would advise to use good shielded cables in all situations.

I’m looking forward to taking the mount on the upcoming trip to Mount Teide, Tenerife to see how well it performs under dark and clear skies 😀


The following wishlist is based on my experience of using the NYX-101 alongside the Ultimate Power Box v2 (Firmware 2.4) and NYX-101 (Firmware X.Y.Z) via the Unity software (1.9.1825.32) :

  • Would be nice to see dust covers provided in the box for all the various ports on the back of the mount.
  • An external aerial port might be useful for the included ESP32 wireless connection ?
  • An option to power other Pegasus items such as the UPBv2 from the aux power port on the mount ? This would mean that then I would only have one cable going up/down from the scope to the mount which is especially useful for those who are mobile and don’t use the NYX mount in a permanent setting.
  • Include a hand controller in the default offering or document compatibility with any existing hand controllers. Could utilise the USB port instead of relying on the ESP32 internal module ?
  • Display the MAC address of the ESP32 module in the Unity app (wi-fi network tab) so it’s not necessary to hunt for it in the router’s client connection pages.
  • A disconnect/reconnect button for an existing wifi connection definition.
  • An editable display box for both the meridian and altitude limits where I can enter the desired value as I can only know what the settings are by actually grabbing the sliders or reading/setting the position from the REST API.
  • API call to set/get horizon & meridian limits as a profile similar to the location. This would allow the user with different scopes/piers/tripods to store different hard horizon/meridian and auto meridian flip settings.
  • If possible add a NYX-101 uptime value to Unity and API similar to other products like the UPBv2 to show how long the NYX-101 has been powered on.
  • If possible add a timer field to the wireless tab to indicate how long the mount has been connected to the configured wireless access point and/or the USB connection.
  • The NYX-101 health status in Unity sometimes doesn’t not render correctly on smaller/different aspect screens between Unity releases such as a Dell 13.3″ laptop.
  • API call to provide NYX-101 health status if the information is not already available via other API calls.
  • API call to indicate if a new firmware (inc version) is available as it is indicated in Unity ?
  • A changelog history for NYX-101, Unity & UPB between versions.


As of May/June 2023 there is now a XT60 cable available to run from the AUX port to run to the UPBv2 and now I only need an adapter cable to fit my 10 Amp PSU with a XT60 connector.

14th June : Firmware 1.21 released by PegasusAstro and the patch notes show this release fixes the DEC axis overshoot experienced by Chris Woodhouse :

  • DEC motor accuracy improvement during slews. In previous firmware declination axis tends to overshoot.
  • Wi-fi hotspot channel width was reduced from 40MHz to 20MHz to improve channel data integrity.
  • Wi-fi hotspot can turn ON and OFF.
  • Wi-fi hotspot channel can be selected from 1 to 11 (11 is the default).
  • Reset home is not allowed when mount is hard encoder limit.
  • Improved accuracy after n-star calibration.
  • Improved mount position store interval.

Viewing Report 2nd June 2020 – IMT3

20:28 – 00:30

After a day of checking the mount and spending some 3 hours resetting the RA and DEC cam stop and spring plungers I have come out to see if I have resolved the image or made it worse. I can still hear the squeaking of the cables in the Through the mount position as the worm turns so I do need to remove 1 or 2 of them to free it up. However I no longer hear the knocking, tapping and grinding of the Dec axis. I am also going to capture some PEC data for Tom on the Software Bisque forum to look at. GingerGeek with his usual smoking jacket turned up to assist from a distance.

Whilst trying to find a star we came across a galaxy, NGC 5646 H126-1, which looked very interesting for the 12″, so we will come back and image that at a later date. We are in a rush for the clouds as it is to cloud over by 11:30pm. What we need to do is disable PEC, disable TPoint and Protrack and the guider relays then point at a star and guide without applying any corrections as per page 147 of the MEII manual for 15 minutes.

I went out to the dome and set with the help of GingerGeek the camera on the back of the 12″ to as close to 0 degrees as possible, in our case 0.81 degrees after plate solving.

We slewed to a start neat declination 0 and close to the Meridian on the East side of the mount called Tycho 326:747 and at 22:37 started to look at the auto-guider settings. The star was at DEC +01° 34′ 10.909″ and RA 14h 45m 20.1920. The auto-guider log in question for tonight was “Autoguider.018.log”. The star looked good in the main ZWO ASI1600mm camera which we would use to guide and collect the data. We did notice as per the image below over 15 minutes the star drifting East, so the polar alignment is out. More importantly we got the 15 minutes of data in the log as the clouds started to roll in, as can be seen in the star brightness below.

Autoguiding in TSX

The resulting log file was read into the Sky’s PEC and the raw data shown below one we clicked ‘Fit’ on the data which scales it to this chart. The peak to peak was 0.7 arcsecs. We applied this to the mount –

Raw PEC data from log
Fitted and applied PEC data

Next whilst GingerGeek went off to get his beauty sleep…..he really needs it 🙂 I set about slewing to a bright star in the vicinity and calibrating the guider, since I had rotated the camera. The calibration was successful even though the RA looked slights odd as a fit. The different in the RA and Dec rate was potentially due to position on the sky and the error in the RA plotting data. I will go back and do another calibration next time it is clear.

Calibration in PHD2

I then slewed to M92, could not find a guide star very suitable so moved around a bit and then started to guide and see what the graph looked like. What surprised me was the the amplitude of the guiding was only 0.36 arcsecs which is really low and no guiding issues as I saw before. It looks like the adjustments to the spring plungers and cam stops may have been the cause and fix.

Guiding graph at +74 deg altitude and near M92

I performed a quick focus run whilst pausing the guiding and got 61836 and HFR 4.4 which is vert good for this scope.

Auto focus

Meanwhile the clouds from the North had started to drift in which was going to stop play 🙁

All Sky Camera

I managed to get a single frame and focus on M92 of 20s before the clouds stopped the guiding. So I shut up the dome, sent the logs to Software Bisque, or the chap on the forum who was kind enough to help and went off to bed.

M92 20s sub

Viewing Report 1st June 2020 – IMT3

20:25 – 00:15

Dome once again open to cool down

Solved FoV for Lodestar guider on 12″

Now guiding on star to West side of mount around 0 degrees Dec and near the Meridian to see if problem reoccurs, graph looks ok but there is a slight regular pattern of error.

Slewed to M92 which is a glob currently at Alt +74, Dec 43 and on the East side of the mount where I had issues last night. I plate solved the image.

The auto focus run looked good

Found guide star by moving M92 slightly off centre. Now guiding. All looked good for a short while. So each section of PHD2 graph is 25 points, so when you have 100 points selected there are 4 sections of the graph. This mean each section/column represents own my case 250 seconds as I expose for 10 seconds, so just over 4 minutes per section. So the errors I saw last night were about 12mins apart. This cannot be the work gear as it has a cycle of 2min 29sec. This is from the latest Paramount manual for the MEII.

  • Tracking at the sidereal rate, one revolution of the worm takes 149.6 seconds (2 minutes 29 seconds).
  • The right ascension gear has 576 teeth.
  • The declination gear has 475 teeth.

The error I am seeing is about 4mins. I cannot continue imaging as every few frames are trailed.

Viewing Report 30th May 2020 – IMT3

5pm – 3:19am

I opened the dome at 5pm. I wanted to try tonight to sort guiding via PHD2 again on the 12″ this evening and then on Esprit120 if enough time allowed.

I changed the PHD2 Profile for 12″ from 6 calibration steps to 12. Performed calibration. Started test guiding in West at +47 Alt. Tried 300 seconds exposure x2 all good

I Slewed back to the East and to Pelican Nebula. Set the Reverse Dec Output After Meridian Flip tick box again ! It then re-calibrated for this side of the mount.

I have also changed the assume Dec orthogonal to the RA axis.

I reran the calibration a number of times until there was no longer an error at the end of the calibration. There was also trailing of stars. Some of the problem seems to have been an incorrect calibration, we need the RA and DEC rates to be very close indeed. Some of ours this evening were 1.5 arcsec difference. The good calibration we finally settled on was 0.5 arcsec difference. The other change was I went out and tightened up the grub screw holding the Lodestar guider on the prism tube that goes into the OAG body, this was loose and I could move the back end of the guider around. This was due to changing the OAG position recently and clearly not tightening the grub screw in enough.

Good calibration
Good guiding after good calibration

I then refocused on Lum and then switched to Ha. This is the image after 300s with a much better HFR of 5.21

Pelican 300s in focus with no trailed stars
Close up of stars from 300s image

When I had a bump in the seeing (assumed) the PHD2 graph looked like this

PHD2 graph bump in seeing

the resulting image of 300s I was in the middle of looked like this :

Image effected by seeing and bump in PHD2 graph

and zoomed in you can see the problem.

Trailed stars due to that seeing bump

Watching Chris Woodhouse’s excellent YouTube video on PHD2 guiding he has also set the min star size to stop it picking up a hot pixel, something we have seen this evening. He has also disabled Star Mass Detection, which stops PHD restarting if it if it thinks another star has been picked even though it may not have, both of these under the brain and guiding tab.

Settings before the change
Minimum star HFD and Star Mass Detection changes

It’s now 2:51am, the sky is brightening but the seeing has settled, the mount is behaving and I am taking 600s Ha images of the Pelican Nebula without any trailing of stars. The odd spike sees a jump up to 3 arcsecs occasionally.

600s Pelican in Ha with good guiding
Close up view of stars at 600s

The guiding graph below shows a really good small RMS below 1 which is key.

PHD good guiding below 1 RMS

So by 3:19am the sky is really getting bright and showing on the SQM as 18.6 and dropping fast. I have stopped guiding and imaging and will now head to bed. The final focus position for Ha was 59925 so I can grab flats tomorrow! I will then take a look at the Esprit120 tomorrow night.

Viewing Report 28th May 2020 – Travel Setup – Combe Gibbet

19:30 – 03:48

Combe Gibbet

Another visit to Combe Gibbet tonight with another astronomer, GingerGeek. After forcing him to leave the comfort and safety of his own home, where his girlfriend gives him tea, coffee and beer and with the luxury of mains electricity, he joined me at the very dark, very blustery sight near 1,000 ft up in the North Downs of Berkshire, formally Hampshire, they moved the line!

We left at 7:30pm and after the 50min trip arrived at the long road up to and past the Gibbet, which is really not much of a road at all.

Not a road, looking down the bottom part of the track

We drove carefully to the top, both parked our cars and set about setting up for the evening. GingerGeek had his Tak FSQ85 on his CEM 60 iOptron mount whilst I setup my usual array of large 4″ binoculars and at first the Mak 180 on the Paramount MyT. Later I would swap to the Esprit 120ED. To celebrate the outing, little geek had brought some beer 🙂

Beer O’Clock!

The Sun soon started to set, the day trippers hung around to watch the sunset and then were gone. I started looking at the Moon through the Altair Astro binoculars which is just a wonderful sight. A Camera cannot capture the experience of seeing the Moon with its Earthshine and in full as the FoV is 1 degree in the binoculars was a wonderful framing.

Moon through binos taken afocal with iPhone 6sPlus

Next up was Venus before it sets, it is amazing just how bright it still is given its phase. I found in the binoculars eventually as it was hidden behind that cloud band in the distance. I then tried to get it in the Mak180, when a few new things happened. Firstly I could not slew to it as I had yet to polar align, so I had to place the scope in the right place. At the focal length of the Mak180, some 2.7m it is difficult to find something faint behind cloud just by pointing. I eventually gave up. I then noticed my laptop power had diminished by nearly 30% over about 20-25 minutes, this was due to Firecapture just hogging the USB bus capturing 100’s fps. So I was going to start the night short on juice! So I turned Firecapture off whilst I went to find Mercury in the binoculars.

Venus through 4″ binos taken afocal with iPhone 6sPlus

Mercury was a challenge, so much so I could not find it, I put that down to that not well placed cloud band. Meanwhile I pointed the Mak180 at the Moon to have a look, but by the time I had finished I the laptop was done to 53% !!!! Not so good.

So it was time to chat to GingerGeek (GG) before I put the Esprit 120 on the mount. GG was having lots of problems setting up. Firstly he had swapped the rings on the mount for the Tak that day and was struggling to balance the scope. It was so bad the scope kept dropping nose first then camera first and then either way depending on its orientation. Eventually, after much cursing, actually a lot of cursing, GG settled for the imbalance and continued to setup, unfortunately not before he knocked his beer over in his boot of the car ? fortunately I did not laugh too much ??

I went back to my setup, placed the Esprit on the mount and then set about getting focus with Ezcap, the software that comes with the ZWO camera. I do find the software very straight forwards and does what it says on the tin as it were. I then slewed to one of the open clusters I wanted to image and realised it resided in the North and that the twilight was still very much apparent so not suitable for imaging. Instead I settled for M51 high up as to the West was the Moon.

M51 300s Image uncalibrated

It is a lovely image at 5 minutes, I could see instantly at least 4 other galaxies and the colour of the main Messier galaxy was very pleasing. I look forward to processing the resulting subs. I set the timer for 1 hour (12x300secs) and went back off for veggie soup, cheese rolls, brownies and coffee that GG had kindly brought along.

crop of uncalibrated 300s M51

GG at this point was having issues focusing for his 5 minutes shot of the Pelican in Ha, he had made some other changes to the software before heading up the hill too which was confounding him. After some more time he finally had focus and started to image. However whilst a few of the images were okay, the resulting imbalance and gusts of wind made it difficult to keep pin sharp images. It should also be notes at this point that GG and I were running from the same car battery, although GG was only running the camera from it, the mount was running from his Lithium battery.

Stunning Pelican Nebula – 300s Ha uncalibrated

At just before 1am the inverter connected to the spare car battery turned off due to loading and power. Everything stopped for both of us ??? however GGs mount kept running due to the Lithium battery. I closed down my setup and allowed GG to reset his camera and reconnect, he then went on to start imaging, however the resulting image had moved significantly and GG decided to give up. So we spend the next 40 minutes packing up. Whilst this was going on we looked at Saturn and Jupiter through the binoculars which was a wonderful sight. Now for the 50 minute drive home to unload the car just before dawn, although by 2am it was clearly getting lighter.

Guiding graph on Esprit 120 Paramount MyT last night, all over the place with wind

The SQM for the site last night was 20.91 although the Moon was very bright. The site is also very dusty, and my laptop was covered in the morning. Another incident was that I inadvertently unscrewed the cover from the guider as I transferred from one scope to another and the glass cover fell out, I now have dust and dirt on the sensor to clean. It is not a great design by ZWO for the ASI290MC as it really needs a locking grub screw to top that happening or a reverse thread.

Herbig-Haro object at the end of the long feature can just be seen.

GGs image has set us on a little project to image the HH 555 bipolar jet at the end of the major turn of gas in the Pelican Nebula. We will attempt over the next few nights to get an image from both the Esprit 120 ED Pro from the IMT3 dome in Ha and also from the OS 12″ to see what it looks like compared to the Tak FSQ85. Another good social distancing astronomy session ? goodnight.

Dwarf Stands Guard At Dusk

Viewing Report 24th May 2020 – Travel Setup

19:00 – 01:12

Tonight I traveled 50mins and 26 miles to Combe Gibbet, a high point for us in the South of England called the North Downs in Berkshire, which at 940ft above sea level places it in the wind, so it is cold but affords a distance from many towns, so it is dark. The is indeed a Gibbet at the top if one should want to take a hanged man or woman and display them for all the surrounding villages to see ? very barbaric, but part of our history.

The car was packed with various astronomy gear, the Mak180 for Lunar and planets.


The Esprit 120 ED Pro.

Esprit 120 ED Pro

And of course the Altair Astro 4″ binoculars with my Paramount MyT mount.

Altair 4″ Binos and Paramount MyT

I met a a social distance my friend Lawrence who was in a much better car than myself more suitable for the off-road terrain of getting to and just past the gibbet. Lawrence brought his trusty binoculars and his deck chair. Meanwhile I setup the 4″ Altair binoculars, the Mak180 OTA on the Paramount MyT and my Canon 6D on a tripod.

All set for tonight
Sun setting

As the Sun set from this location we spied Venus first and took a look through the binos.

Moon, Mercury and Venus

I captured some frames in the Mak180 with the ZWO 294MC camera. We then moved to the sliver of a Moon 2.8% illuminated and 1.6 days old. I placed the Mak180 on this for a few frames also. Lastly we moved the binos to Mercury, which is unbelievably small. Very faint in the twilight sky and surprisingly faint in the binos. I once again slewed the Mak180 and captured some 4GB files.

Lawrence looking at the Moon

We then went a hunting for comet C/2020 F8 SWAN but it did not appear in the star field where it should be despite being able to see Mag 8.9 star. The comet was purportedly magnitude 5.8 but this was not the case. I checked my ephemeris on both SkySafari and The SkyX and I wass definetly in the right part of the sky and confirmed the star paterns from my star hoping, but alas no comet.

Lawrence looking at Mercury

So although the wind was now dying down both Lawrence and I were cold so at just gone midnight we packed up and set off home. I must remover by coat tomorrow!

Addendum, I had read an article the following day that the comet may have broken up but I cannot yet confirm this.

Viewing Report 21st April 2020 – IMT3

Viewing time period – 22:05 – 03:36

Update on viewing with Bob running IMT3 for the night.

So after joining the BAS Zoom session I asked what others were imaging and got a spiral galaxy NGC4535 from Trevor and the Needle NGC4565 from Mil Dave.

I slewed to NGC4535 which included a meridian flip and found it pretty much in the centre of the fov. Started a sequence of 3, 5, 10, 12, 15, 20 minute subs but aborted after the 15min subs as trailing was evident. Focus could also have been improved.

NGC 4535 720s (unguided) Exposure L

NGC4535 and NGC4565 were approaching the meridian so I did a flip to Praecipua in Leo Minor and then a slew to some nearby fainter stars to do a focus run. Start Focus position was 75542 at a temp of 14.14. After focus run the new focus position was 73335 HFR 4.7 98%.

Now slewed to NGC4565 and set a sequence of 12.5m (750s), 13.5m (810s), 14.5m (870s) subs going trying to establish where the limit is for unguided in these conditions. The first 750s sub was fine but the 810s was just showing a little elongation. I aborted the 870s sub and started a run of 12.5m (750s) subs going to see how consistent the results are … will need to look at these in the morning but I think this is about the limit and would probably back off to just 10m subs to provide a bit of a buffer.

NGC 4565 750s (unguided) exposure L

Viewing Report 15th April 2020 – IMT3 – Final TPoint…..

Viewing time period – 18:16 – 23:15

Here is my workflow so I can repeat each night until this is finished.

Open dome – done

cool down – done

turn off dehumidifier – done

turn off fans on scope – done

find home – done

focus – done 60,535 clear

remove existing model – done

slew and sync to nearby star – done

make sure scale is correct -done

make sure image link to all sky database is selected – done

start TPoint run – done @ 21:13

Complete TPoint – 93 points done, paused TPointing at 23:15

Turn on Dehumidifer – done

Note that tonight I found the dome was definitely not lining up with the 12″ OTA. We have noticed this gradually becoming as problem over the past weeks and months. I am not sure if this is a problem with software, hardware, a change in settings or the temperature of the dome in some way has effected this. To this end I will set about a calibration run of the dome tomorrow to see if that can rectify the issue.

Viewing Report 16th April 2020 – IMT3 – Final TPoint again…..

Viewing time period – 20:59 – 23:42

Here is my workflow so I can repeat each night until this is finished.

Open dome – done

cool down – done

turn off dehumidifier – done

turn off fans on scope – done

find home – not needed

focus – done 59,659 clear – done


slew and sync to nearby star – done at 21:06 as not dark enough before then

Not quite dark enough yet

make sure scale is correct -done

make sure image link to all sky database is selected – done

All Sky Image Link settings

start TPoint run at point 93 – done @ 21:10

Complete TPoint – 231 points done at 23:46 including checking 5min unguided exposure which was fine

Final TPoint plus Super Model

Turn on Dehumidifer – done

So what did I learn tonight? It was worth doing the TPoint model. The resulting pointing accuracy is much better with objects being almost centre off the chip. Unguided images on the 12″ look good at 5mins, I will try longer when the clouds and rain disappear. That following a documented approach helps as above. The adjustments to the worm and the loose weight helped. That fixing the dome rotation slippage on the encoder today helped.

TPoint completion of 231 points
Final model applied
Polar alignment report
Command line view
Protrack on
Tpoint model on sky
2min unguided image through OS12″
5min unguided exposure through OS12″

I mentioned above the dome slipping on the encoder, this was because of the small weak spring that is used on the dome, which is not good enough and over the past year has stretched beyond its limit. This means as the dome rotates and the dome shudders due to the joins in the dome not being flush (another issue) and thus the spring is stretched. This meant that some of the time the encoder wheel seen below was not touching the dome and therefore lost around 30-40 degrees. To rectify I have temporarily stretched and tightened the spring which we will replace later with a more suitable one.

Encoder wheel
Encoder spring now stretched to fix problem

Viewing Report 14th April 2020 – IMT3 – Last TPoint…..

Viewing time period – 20:30 – 22:30

Tried again to get the TPoint completed tonight but hit with a load of issues which I will try to sort tomorrow. FoV in TSX was wrong. Not plate solving in TSX. Focus potentially an issue. Use of All Sky Image Link for Scripted Image Link needed to be selected from the Image Link –> All Sky tab. Image scale in various places was incorrect again and should be 0.32. Managed to get to 10 points with 3 failed. Clearly something has changed given this worked a week ago. I will attempt a go tomorrow night to resolve. Meanwhile I have left Bob to image. In hindsight we should also be leaving the observatory running all night as when I got up at 4am it was crystal clear and dome was closed as nothing planned, so a default object and scope setting should be used and left running. However, Bob did manage to grab some frames in the clear of M53 until what looks like 3am so that is better than nothing.

Viewing Report 13th April 2020 – IMT3 – Last TPoint ?

Viewing time period – 20:32 – 22:13

Dome has been open a few hours now and the 12″ cooling down with the fans on.

At first the TPoint run was not solving the image, I had to change again the Image scale which was set to 0.01 for the automated TPointing back to 0.32.

Once this was done I started a new TPoint run. The new numbers coming in looked better on the scatter graph, however at about 29 points the mount stalled and the TPoint stopped. So I went out and backed off, turning anti-clockwise the spring screws 1/8 turn on the RA axis. I then restarted the mount, but now it is too late to start again as I have work tomorrow. So I will leave the mount in Bob’s capable hands and head off to bed.

Viewing Report 10th April 2020 – IMT3 – TPoint again part 1

Viewing time period – 20:36 – 00:33

Another night of trying to complete a TPoint run. After opening the dome around 4pm to cool down and turning the fans on the 12″ and pulling back the light shield material we (Bob, GingerGeek and I) @20:49 completed Slew and Sync to test plate solving ability which worked well.

First Solve and Sync works

We then started the TPoint run.

Starting TPoint Run
First point captured out of 231 points

Our first failure was Point 28 @21:21. The following are other failures.

Failed Point 50,51,52,53 @21:42

Failed Point 55 @21:45

Failed Point 60 @21:53

Failed Point 71,76,77,78,79,80,81,84,85,86,89,

TPoint failures

We then performed the first of a few meridian flips back and forth at Point 92

Meridian Flip

At pointing sample 96 we changed from 20s exp to 25s (20 failed at this point) to see if this helped the failure rate, it helped a little. The sky clarity was not great nor was the 12″ pointing correctly through the dome at the Meridian so need to look at this at a future point.

More Tpoints failed as follows. TPoint 100,102,105,106,107 (at this point scope 1/3 obscured by slit!)


Failed TPoint 109,110,112,113,114,116

By 11pm after 2 hour we had completed 122 points

Failed TPoint 123,127,128,129,130,131,132,133,134,135

@23:39 stopped due to cloud

@00:33 stopped again due to cloud and shut dome but left TPoint session unfinished to see if we can pick up tomorrow night if clear.

Viewing Report 7th April 2020 – IMT3 – TPoint Failed

Viewing time period – 20:54 – 22:30

Old TPoint Model before new run

Tonight I set out to perform a TPoint run to improve the values we got last October. However it transpired to be more difficult than I thought. We updated TSX after October to there latest release, this seemed to have changed some of the parameters for plate solving. This meant that every time we took an image in the TSX it would not plate solve and so we could not perform the TPoint run. After the best part of 1 hour I gave up and let Bob take over the scope to play.

Meanwhile I then setup the Mac 180 to image Venus, however, by the time I got round to it and found it in the telescope and thus on the chip it was low down the side of the house opposite by the roof and was bumping around badly due to thermals. I found it difficult to centre the scope on Venus with such a small chip so I may need a more repeatable way of doing this moving forwards. I took a couple of videos just for posterity even though I felt the quality would be poor.

Subsequently the following day I opened up the images take with TSX and also download the All Sky Database that was missing to both the NUC in the dome and my local Mac. I then started to change the settings in Image Link within TSX until I could solve the image.

Solved image using Image Link All Sky Search in TSX

The key parameter transpired to be the Image Scale Tolerance on the All Sky tab setting it to 5% from 1%. Also I changed the Image Scale back to 0.32. On the Setup tab I selected Setup under Source Extraction and changed the detection to 10.0 and the minimum number of pixels to 20.0.

New Source Extraction Settings and solved image

I then tried a second image and that solved in 1 sec too so very happy. I will try to give the TPoint another go tonight as well as Venus on the Mac 180. If TPoint works I will take RGB on the Tak. First solution from the image I solved can be seen below.

TSX Image Link solved

The resulting astrometric solution from TSX is below based on another 60s exposure image is below as text.


Center RA (2000.0): 07h 14m 12.34s

Center Dec (2000.0): +32° 34' 16.1"

Scale: 0.3250 arcseconds/pixel

Size (pixels): 4656 x 3520

Angular Size: 0° 25' 13" x 0° 19' 04"
Position Angle: 195° 28' from north through east

Mirror Image: No

RMS: 0.88 (X: 0.45 Y: 0.75)

Number of Stars Used in Solution: 40 (100%)

FWHM: 8.98 pixels, 2.92 arcseconds


Things still to resolve

  1. Check out why WSX is loosing connection and shutting the dome
  2. Clean filters for the 12″ to get rid of doughnuts
  3. Clean sensor for QHY168C

Viewing Report 5th/6th October 2019 – Travel Scope – Tenerife

Viewing time period – 21:20 – 01:11

Moon and Saturn

This evening started with the Moon high in the sky and waxing its way to half. Next to it Saturn sat, close in fact, so close I pointed the scope at it, around 22:30 and both the Moon and Saturn fit in the same field of view 🙂

So I took a few exposures, worried that either the Moon would be overexposed or Saturn underexposed. I settled on 0.001s and took a bunch of shots. Below is my setup by the light of my rather bright head torch, turned on only for this photo I might add.

Esprit 120 and MyT

Next it was back to trying to resolve the guiding issues that had troubled me the night before. The good news was Tom from the Software Bisque website (not the Tom Bisque, another Tom) had come back with a few suggestions and questions that made me think. I had a good set of guide stars to choose from.

Hw many guide stars!

The autoguide Setup window is where I would spend most of my time I was sure, changing parameters.

Guider settings

I recalibrated the mount, this time using 100arcsec as the parameter. The previous calibration run produced a rather short cross.

Poor calibration ?

This gave me a better ‘cross’ and I think should improve the guiding, although I am still skeptical about just how quick it calibrates, some 4-5 seconds.

Better calibration

Back to guiding the mount was still all over the place, I am convinced it is overcorrecting, on the basis if I don’t guide I get better stars up to 45s or so. I added in a much longer settle period and this seemed to help, but still the graph is a long way from the sort of guiding I was getting before they updated the software.

Poor guiding

The wind was a bit gusty tonight as last night and for sure this was not helping, you can tell from a few exposures it was wind related jumps and drifting

I sat back after a while of changing different settings feeling that it was not improving, so I took a whole bunch of images, only 90s of the Sharpless object Trevor had mentioned, SH2-101 which is called the Tulip nebula. Trevor had produced a lovely image from his 14″ in the UK so I thought I would have a quick go, knowing most of the frames would be lost.

Final set of guider settings

So by 00:30 I decided to start to pack up, the wind had picked up, I was cold, the guiding was still a problem, so by just gone 1am I was heading down the mountain, some 1 hour and 20min drive! The final view from the bridge as it were was this.

View from TSX

The next day I processed the data for the Sharpless object and it was ok, given the short amount of data. One for the 12″ I think.

SH2-101 Tulip Nebula

Meanwhile I processed a single image of the Moon and Saturn and was pleased with the result as seen above. Here is a version with Saturn as an insert.

Viewing Report 4th/5th October 2019 – Travel Scope – Tenerife

Viewing time period – 23:58 – 03:38

So I have arrived in Tenerife and for a few nights only I am up at the MONS observatory, using the plateau (concrete platform with power) outside the dome.

It was dark when I arrived at 20:15 so I am setting up by head torch and given the tripod and mount and scope are all in bits it has taken some time to put it back together.

I setup in the corner where Bob normally sits as thee were a bunch of students using the scopes normally kept in the sheds outside. After setting up I panicked as I had forgot my UK to EU plug ! I asked the lady leading the student outreach and she let me in the MONS and I searched for a plug and found one, despite everything being emptied out due to the MONS having work done to it. However on testing the plug it did not work 🙁

A call to the operator did not produced anything. So I tore down the scope and packed in the car, very disheartened. As I was just about to head off the operator arrived with another plug ! I took my laptop and tried it, but it did not work either. It took a while to work out but of course the power had been turned off from the fuse box and flicking the RCD produced power and so reluctantly I emptied the car and went about setting back up 🙁

By this time it was approaching midnight and I had been at this for some 4 hours. I started the laptop, found I was pointing almost spot on to Polaris, so using my Polemaster it took a few minutes to adjust. I then set about slewing to a nearby object, syncing and then finding a guide star, at this point my troubles where just about to begin. It was now 1am.

So after setting the temperature of the camera to -25℃ and the gain to 7 and offset to 20 I found the scope would not guide. It was bouncing all over the place, some of it was the wind, but some of it was erratic behaviour of the mount, so it seemed like it was overcorrecting. I started to change some of the settings but t no avail. All I could do was to shortened the exposure to around 90 seconds and try and get some data, even if the stars were slightly trailed. I would try to take a longer look at the guiding tomorrow night.

Not so great guiding

So I slewed to one of the objects I was to target, a galaxy called NGC 891 in Andromeda and started collecting data. All in all I grabbed 44 images before the guider was causing so much of an issue even 90 seconds was too long (processed image below)

I then slewed to M45 in Taurus but still the guiding problems persisted. I took 4 x 90 second images and then decided to call it a night at around 3:30am.

Now for packing up the scope and the 1 hour 20 minute drive back down the mountain. How I miss observing from Hacienda on La Palma!

DirectGuide and the Paramount ME II

So I used to be able to guide on the Paramount ME without the need for an ST-4 guider cable. This is achieved through information being shared about the position of the star to PHD2 and it then sending commands to the relays on the Paramount ME, however I had yet to be able to get this working with the Paramount ME II and using SGPro as the host program.

So for a short period on the evening of 5th August 2019 I ventured out to complete the setup and get the guider working.

As information is key I had spent time re-reading pieces of the Paramount User Manual, The Sky X Manual and the PHD2 Manual, the later having partial information needed to setup, another piece of information was in The Sky X Manual.

So what did I do? Well DirectGuide is a bit like Pulse guiding that is supported on other mounts, however for the Paramount ME II pulse guiding is NOT supported. So you need to configure and setup for Direct Guide, but where?

Looking at the Connect Equipment window in PHD2 you are presented with 3 options, How to connect the camera, how to connect the mount and a 3rd option around how to connect an Aux mount. It is important to understand when to use that 3rd option around Aux mount as that is what can cause confusion when trying to get Direct Guiding to work.

Aux Mount should only be chosen if you are using an ST-4 cable, if you are not then this option should remain set to None. If you inadvertently select ASCOM Telescope Driver for The Sky within this box the mount will not behave correctly. So leave it set to None!

Configuring Camera and Mount ONLY

Camera needs to be set for the camera of choice, for me my trusty Starlight Xpress Lodestar is selected. For the Mount I selected ASCOM Telescope Driver for The Sky. Next you need to configure the Mount by clicking on the spanner and screwdriver icon next to the option.

Under here you can configure The Sky Controller Driver Setup, selecting The Sky version, X Pro for me and various options for the mount itself. The key checkbox is Use DirectGuide. This menu of options is from the ASCOM Chooser and you should select any settings you wish to enable. Mine can be seen below.

ASCOM Chooser for Mount and DirectGuide setting

I quickly configured the Camera also and below are the settings that work well.

SX Lodestar Camera Configuration

On connecting to both the camera and mount, selecting a guide star and calibrating the guider it is apparent that I have configured the setup correctly. All is now well with the guiding and it produces a smooth chart with tonights seeing as can be seen after several dips produced by cloud at the begging of the guider graph.

Smooth guiding after cloud disappears