Optec Flip-Flat Service – Vendor Review

So during the ongoing Human Malware situation we have been concentrating on imaging asteroids, comets and more recently performing exoplanet measurements on the 12inch RC than long exposure deep sky astrophotography.

Astronomy is one those hobbies that is for most part is sole activity for the dark early hours of the morning and these days is usually done remotely. It was therefore disappointing that when one of the team went to use the Sky-Watcher Esprit 120ED for a night of astrophotography and found that he was unable to open the Optec Alnitak Flip-Flat. As the lockdown and travel restrictions progressed due to the initial wave of the human malware situation the issue was soon forgotten as we continued our focus to performing exoplanet observations on the 12inch RC for the ESA Ariel Mission.

Now that IMT3 has been decommissioned ready for it to be reborn as IMT3b at it’s new rural darker sky site I decided to take the opportunity to retrieve the FlipFlat and diagnose the issue at home on my desk.

Using the Alnitak controller software, I could hear the motor running but it never seemed to complete the close or open. All it continued to display was the TIMEDOUT message as shown below.

Timing out !

I sent an email off to the vendor I purchased it from but after a month I got no reply. In the hope I would not be left with an expensive paperweight I reached out to Optec. After quite a few weeks of getting no reply I was pleasantly surprised to receive a message from Jeff Dickerman (President) of Optec. Jeff apologised for not responding earlier and offered to help resolving the issue. The error message seemed to be a known issue and it was generally an easy resolution which required taking the box apart. Jeff sent me instructions on how to take the unit apart and fix the problem.

You’ll see the motor is attached to an internal wall with a modified shoulder screw and stack of Belleville washers.  These spring washers are used to allow the arm to slip when someone grabs the lamp and physically tries to force the cover closed.  Unfortunately they can also allow the arm to slip during an open or close operation which leads to that dreaded “TIMED OUT” message.  Optec have redesigned the stack a bit to eliminate this issue going forward. 

To correct, you might be able to adjust the washer stack by removing the lock nut and sliding off the washer stack to the pivot arm.  Check carefully to see if the shoulder screw protrudes beyond the pivot arm.  If so, rather than installing the cork washer next, install a 5/16” ID washer first to cover the exposed shoulder.  Next add the cork washer and stack of Belleville washers.  Finally screw the lock nut back in place and tighten while holding the shoulder screw near the motor (this is important to avoid breaking the internal motor gears).

Step 1 – Pry open clamshell
Step 2 – Shows what to secure
Step 3 – Tools needed
Step 4 –
Step 5 – Check shoulder visibility
Step 5a – Shoulder
Step 6 – Washer Stack

In the end I decided to courier the unit back to Optec for repair as I did not want to render my unit completely useless in case I made a mistake.

I’m extremely grateful to Jeff, Tina and the team at Optec for all there help, patience and understanding. I’m a very happy customer and the flip-flat will be rejoining the Esprit120 when the IMT relocation is complete at it’s new rural location. I can then do a Homer Simpson and annoy Dave with “Flap goes open, flap goes shut, flap goes open ……”

Viewing Report – Cinco de Mayo 2020

Moon 96% Waning.

Our TOSA Manual needs updating now that we have replaced the HiTechAstro Deluxe Cloud Sensor with the Lunático AAG CloudWatcher cloud detector.

New Screens to get familiar with:







Initially I was unable to open the shutter of the dome. Thinking I’d forgotten to reset the HiTechAstro relay I soon realised I had to figure out why the AAG_Cloudwatcher software was reporting Unsafe. GingerGeek spotted that the Brightness level looked like a sawtooth and should settle after a few minutes, which it appeared to do and the dome shutter opened successfully.

Following on from my previous observing session on 1st May when clouds interrupted play just as I was completing a Guiding Assistant run in PHD2, I started tonight’s session with a quick look at Venus before it set below our horizon and then had another go at running the Guiding Assistant in PHD2 for the OS 12″ / Tak FS-102 combination, with the Tak as the guider for the Officina Stellare.

Venus in Ha (because it’s so bright).


As the Tak has an Alnitak Flip Flat attached to it I added it to the profile I’ve created for the OS12 and Tak combination so that the panel can be opened to allow light through to the camera 🙂

Guiding Assistant completed successfully and values applied for RA MnMo, Dec MnMo and Dec Backlash compensation.


Y scale = 2, Target Radius = 1.5

Sequence running for 2, 5, 7, 10, 12 and 15minutes.

2, 5,& 7 minutes exposures ok but trailing beginning to show at 10 minutes, quite evident at 12 minutes and very evident at 15 minutes.

Added 8 and 9 minutes to sequence, but both of these show signs of stars trailing.

Started a sequence of 24 x 5 minute exposures.

Aborted at frame 20 as the NGC3628 was now below the horizon.

The image has drifted and NGC 3628 has not remained fixed in the frame, so we still have issues with guiding as that is almost certainly the source of the drift.

02:22 Slew to M5, just off centre.

Slew to HIP 74975 to centre and focus.

De-selected guider.

02:57 Slewed to M5 and started a sequence of 24 x Lum and 8 x R,G,B 120s frames.

Sample Luminance frame:

04:08 SQM graph has started to droop. Was 18.2 before 4am, now down to 18

04:10 ASC image brightening quickly

04:15 SQM 17.54

04:24 Camera Warming Up

Disconnected Guider

Telescope Parked and disconnected.

Dome Parked (shutter closed) and disconnected

De-humidifier on.

Camera Power Off

04:30 I’m off to bed

Viewing Report 20th/21st July 2019 – IMT3 Observatory & Travel Scope

Viewing time period – 21:15 – 02:15

There were two things I wanted to do tonight, one was to get first light with GingerGeek through the Skywatcher Esprit 120ED, the other was to setup my Esprit 120 on the MyT in the garden and grab a photo of the Moon to celebrate 50 years since Neil and Buzz stepped out onto the lunar surface. As a bonus I wanted to to get the guiding working on the MyT too.

As GingerGeek opened the dome on the IMT3 I setup the portable gear on the patio. I connected the setup to a 12V car battery to see how well it did at running the Mount and the camera. The initial voltage of the battery was 13.1v when I started. I connected the camera to EZCap and the Mount to TheSkyX (TSX).

Meanwhile GingerGeek opened the dome, connected the mount, opened the very geeky but cool Flip Flap covering the Esprit 120 and slewed to a bright star for deterring the focus and the position relative to the 12″ main scope.

Remarkably the focus was fairly near and after a few iterations GingerGeek managed to get the V curve sorted for good focus. Before this was done he setup the Luminance filter on the filter wheel control with SGPro that had not been configured. I then looked at the resulting image and determined the FoV within TSX. The field almost fits the 12″ and so the position is fairly close, close enough for solving and being in the right area for imaging. There was an error by SGPro complaining about 800px difference with what was to be expected, the problem being the difference in the angle of the Esprit 120 vs where the mount knows it is pointing as shown through the 12″.

Despite that we managed to take an image and then move on to see if we could guide with the 12″ off-axis guider for the Esprit. This worked a little but the guider graph was way off at various points, I believe this is potentially either a setup issue on the guider and/or the fact that we are too frequently taking too many images to correct and thus chasing the seeing. I will look at this next time are out.

Back on the portable setup, I managed to very quickly connect, perform polar alignment using the PoleMaster and the new bracket I fitted. I then slewed to a star which was not quite in the FoV so I need to spend more time on this next time I am out. No problems though, I nudged the scope and found the star. Performing a sync on this solved any further slewing problems.

I then waited for the Moon to come up over the roof tops which was unfortunately not until 2am of the 21st thus slightly missing the landing date of 20th by 2 hours (Eagle landed at 9:17pm BST) but non the less still obtaining an image of the Moon to celebrate the 50th anniversary of the first lunar landing at the time Neil put that famous foot on the Moon at 1:56am BST on the 21st July 1969 🙂

Apollo 11 50th Anniversary

GingerGeek managed to get a few images but nothing much was showing on them especially the Elephant Trunk nebula he was imaging, I suspect, but am not sure, the wrong filter was selected so probably OIII rather than Ha as a previous Frame and Focus command through SGPro for 15 seconds showed the Elephant Trunk, at this point we were taking 10 minute exposures so it should have easily been visible. Again another problem to sort next time we are out.