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.
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).
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 ……”
So we started the decommissioning of IMT3, dome and all ready for the move to a new darker site location. The new incarnation once installed will be known as IMT3b. As part of the process the Esprit120 will be relocated to a separate pier mount in a RoR shed to be known as IMT3c.
Decided to have a quick look out before moving house, given it was supposed to be cloudy and there is a bit of a clear spell. I have decided to just take a look at a few objects. First up is the Cheeseburger Nebula NGC 7026.
Next up is IC63 which is a ghost nebula that Tim imaged the other night, I want to see what it looks like in my 12″ vs his 10″. The first thing I noticed was in the guider window that the reflection of the bright star Gamma Cas caused an interesting image.
Next I am going to go after M110.
I have now slewed to M32 just below.
The last object of tonight and then off to bed so I can be up to help Bob concrete IMT4 tomorrow is NGC 508.
Imaging with GingerGeek for another exoplanet. This one starts its pre-transit at 23:55 and should just about be on the point at the meridian where we can perform a meridian flip and then image all night.
We like to make sure we have the right star field so actually having a photo from the exoclock website helps. Tonights candidate is the dimmer star to the left of this pair.
The star is a magnitude 10 star in Lacerta. Unfortunately despite the forecast it has just clouded over, here is what we would have been imaging.
So the evening started well, I had logged into IMT3, got the dome ready, TheSkyX/SGPro software was up and running, CMOS camera was cooled and I was already syncing on a bright star even though it was still twilight.
Dave and I had chatted the previous night and had settled on HAT-P-32b in the constellation of Andromeda. The reason was due to the target position in the sky, the time of rising and setting was before the rise of the sun so we could get a full ingress and egress and no meridian flip was required.
Then the gremlins started to play havoc with our efforts and I was having major issue with guiding to the point that I was going to give up as the issues were eating into the desired 1 hour egress monitoring time period. Dave joined the session to help resolve the issue and we managed to start imaging about 10 minutes before the start of the transit.
Dave had to go to bed due to work commitments but I was determined to get the full set of observation and run it through the HOPS analysis software. It was an uneventful night interspaced with music, movies and hot cups of tea.
Once I had transferred the data over the internet to my server, performed the analysis and sent the result to Dave it was 5:30am so I crawled into bed around 6am.
Session period 19:00 – 01:18, transit start ~23:06 and end ~02:37
Before I move house, we are going to try and grab another exoplanet or two or possibly three…..we’ll see. Tonight whilst it is currently clear and due to cloud over by 1am, we will go for HAT-P-6b that is on alert from Exoclock.
The transit end time is after it is due to cloud over but we may be able to get the start of the transit and some useful data to possibly half way through. So I have opened the dome, started to cool the 12″ down and slewed to a magnitude 4.29 star in the vicinity of Andromeda called HIP 116631 also known as 17 Iota Andromedae in the Flamsteed catalogue so that I can slew and centre on the object when it gets dark.
I’ve now manually centred the star due to the brightness of the sky still and synced in The Sky X
I’m now waiting for a bit more darkness to perform the first focus run.
At 20:31 I performed a focus run on the mag 4.29 star with the red filter and got position 63007 @ HFR 5.2 and temperature at the focuser of 17.28℃.
I have performed another solve and sync as I had left the scope running for a while without guiding and the star had moved slightly.
I have now taken a quick 20 second exposure of the target to confirm it was the right star as per the star chart from the Exoclock website and it was.
I have started guiding on a nearby star with PHD2.
HAT-P-6b rising from the East as can be seen in TSX.
So here is a 2 minute exposure of the target. I tried 60 second but given I am running Gain 10 Offset 10 the maximum pixel count for the centre of the star was 1,648 out of 65k. So a 2 minute exposure produces 9,488 which is still low but I will continue on the low side for now. 1 hour before the transit is in about 45 minutes so I will wait then start gathering data.
So we’ve started and set to run for 5.5 hours, this means a a meridian flip in 4 hours time so I will need to stay up until 2am, perform the flip then head back to bed.
The clouds have started to roll in, however so far we have been lucky and our star and planet are just outside the bank of cloud …… but for how long?
So it finally clouded over around 1am although the data for the past 20 minutes is suspect, so I hope we at least have the first half of the transit.
Session period 21:00 – 23:57, transit start ~21:16 and end ~00:05
Started with Lum autofocus at 21:17 but on changing to the Red filter the HFR rose to 8.5 so refocused on Red at 21:20, position 60789, HFR 3.97 at 21℃. The change in HFR was more likely the warm sky and seeing conditions.
Restarted imaging at 21:39 at new Gain 10 and Offset 10 with a 15 second exposure to get the exposure down well below the 65k max to around 35k. The target star is a magnitude +7.69 so the initial Gain 139 Offset 21 and even Gain 75 Offset 12 were too high even at 10 seconds exposure.
We started with no delay in between the exposures until the start of the transit, then decided due to the large amount of data (35GB) being collected we should put a delay in which we did of 60 seconds. In hindsight we should be placed a smaller delay period in 15-30 seconds to allow us to gather more data points for the transit period. We have emailed the ESA team to start a conversation on planning exposure/delay settings for transits.
We then finished was forced to finish before the projected transit was completed when the clouds rolled in, and took Dark, Bias and Flats frame at Gain 10, Offset 10 ready for the analysis software.
After reviewing the data and the monitoring graphs it is obvious that the less than desirable Sky Temperature showed it was not truly clear. Below is the effect of high haze and cloud passing across the sky during our observation session. It should be noted that we have not had sky with a reading <= -18℃ since mid July.
How much impact this has on the observation and measurements we will discuss with the Exoplanet team.
22:00 – 01:44 (GingerGeek came over and Bob was remote)
So the original plan was to perform another exoplanet observation and improve/learn from our previous experiences. However the weather did not look like it was going to be accommodating so we decided to change plans.
At first we planned to take a shot of Pluto and then go back to it later on in the month to see how far it had moved but it was low and below the the IMT3 visible horizon.
Next up was to continue imaging Messier objects for Dave’s Messier Marathon collection. We settled on M14 and had created and started an imaging sequence but again the clouds rolled in putting a stop once more to some constructive imaging.
So we then decided to track an asteroid for as long as we could before the clouds stopped us. Once Dave had loaded the asteroid database into TheSkyX we then choose one close by to the previously planned Exoplanet. The asteroid 85275 1994 LY (magnitude 14.01) was in the constellation of Ophiuchus.
We turned off PHD autoguiding and mount control in the SGPro control panel as we were going to be using mount tracking on the asteroid instead of sidereal.
Autofocus using Luminance filter – 60,389 position, HFR 5.0, Temp 24.94℃. We started at 22:46 and took a series of 30 second images until the cloud cover stopped us. Dave then used the Pixinsight blink script to stitch the resulting FITS->PNG images into a movie, then looped the short AVI, added titles and music in iMovie (best viewed full screen and in HD).
@ 19:00 Opened dome in order to cool the dome and scope down.
@ 21:00 GingerGeek arrives, wine is poured and we took 5 x darks, flats and bias for both the last run and tonight. The flats (red) were 3 seconds exposure to get 2/3 well depth required for this.
@ 21:44 Slewed to WASP-93b before we set about focusing on a nearby magnitude 5 star using the Red filter. Starting focus position was firstname.lastname@example.org℃.
@ 22:06 After failing to focus using the Red filter we resorted to using the Luminance filter to auto focus and achieved a excellent fit (focus position 61630, HFR 4.95 @20.83℃).
When we swapped back to the Red filter, SGPro then moved the filter offset to focuser position 60630. We slewed back to WASP-93b (GSC:3261:1703) and found a guide star just off centre of the star field with the exoplanet target.
Started to take exposures to find the brightest value of the centre pixel of the star and make sure it was 2/3 full well depth and thus 33,000 ADU (even though it is a 12-bit camera SGPro is set to 16-bit for ease of use. Eventually this was achieved at around 200 second exposure.
@ 22:51 Started imaging, 18.21℃ was measured at the focuser.
Started around 21:15, Guiding by 22:02, Capture started 22:22, Finished at 03:31.
Dave and I are part of the amateur exoplanet monitoring effort for the ESA Ariel mission. We decided that we would allocate some time to try and provide observing data towards the project whenever we could.
Part of this requires some forward planning such as looking at the upcoming transit visible and their associated time. This is due to the altitude of the object, the ingress and the egress times of the projected transit.
Prior to this we had discussed in advance which object to target for the chosen evening. All the hard work of choosing objects is done by the Exospies project website as they list the candidates they need data for via a schedule. So it’s a simple task for use to go through the list and work out what fits best for us.
Unfortunately whilst opening the dome to cool down I decided to review the schedule but I was hit with a server 500 error from the website. In a panic that I might miss the start of the event I scoured the internet for alternate exoplanet transit time websites and found the excellent Exoplanet Transit Database of the Czech Astronomical Society.
I had issues with focus drift all night due to the temperature fluctuations but at a recent Zoom session it was discussed that images can be out of focus with no detrimental effect on the measurements :
I was unable to auto focus successfully maybe due to the low altitude and seeing. I also discovered that temperature compensation was enabled so we probably need to remeasure the temperature compensation coefficients so the focus deltas are better between the par focal filters.
The object was at a relative low altitude, the outside temperature was warm and although the skies appeared clear our AAG CloudWatcher sensors via the Grafana dashboard told a different story. For us a truly clear sky is anything equal or lower than -18℃.
After performing a meridian flip, resumed the guiding I started to feel tired so I set my alarm for 3am and went to bed. Unfortunately there appeared to be a guiding issue at some point shortly I went to bed.
This was investigated using the phdLogViewer and shown to be a loss of guide star and didn’t recover for around 18 minutes.
The guiding issue also caused the image to shift so the target and reference stars moved. We need this in frame in order to run the frames through the provided HOPs data analysis program which hopefully won’t have a problem in reading them. That’s an exercise for this weekend and hopefully we will have enough data to yield a decent light curve that we can submit.
GingerGeek and I were out imaging tonight. The sky unexpectedly cleared and we thought given the impending move of IMT3 to another site that we would try to gather some more data on M57, specifically LRGB and some additional Ha on the 12″.
We ran Autofocus on Luminance which gave 60,671 at 20.64℃ and HFR 6.5. We then started to image and after a few frames the temperature started to drop. In the main this is because we opened the dome last minute rather than a minimum of 2 hours before we used it so the dome was warm and now cooling down the optical train shifts.
We refocused to 62,712 on luminance at 19.10 with an of HFR 5.15. We then ran the image acquisition and below is a screenshot of the guiding, which looked like it was going to cause an issue but it was ok. If it had then it would have been the local fog rather than anything on the mount. At midnight we performed a Meridian flip nice and early which afforded us to leave the observatory running and go to bed. Notice the graph below, the yellow line drops as we performed the meridian flip, this is due to the dome now shielding against next doors light !!!!!!!
The neighbours light continue to be a pain as can be seen here, I really cannot wait to move the observatory to it’s new dark site.
Finally managed to capture LRGB and Ha, below the RGB and Ha frames can be seen in PI. Note the central star is not visible in the Ha frame,
Finally I stacked 1 of each colour without calibration to see what it would look like.
So we left the observatory imaging, I had a quick peek outside around 12:30am and there was water running off the dome and the outside windows of the orangery! The Observatory ran until the dome shut at 3:58am (it woke me up) when the light levels started to rise.
I opened the dome at 8:30pm and then went off to do some more work. A few calls later and it was time to come back and see if I could grab comet C/2020 F3 NEOWISE which had now moved further West and further in altitude over the past week, meaning it should be visible from the dome. Below is Arcturus as I performed a quick sync.
Below you can see Arcturus on The Sky X with the dome slit showing and the obstructions from the horizon also present.
Comet NEOWISE can be seen just above next doors tree.
A quick peek with the camera and I could just make out the comet.
Clearly more clouds rolled in which is typical
Looking at the cameras in the dome I could see the cloud bank of cloud (picture top right)
Fortunately the comet could be seen at the back of the cloud bank.
So I set about quickly taking some images before the comet disappeared behind the tree.
The other useful thing tonight was using the monitoring GingerGeek put together. Below are a selection of shots from the website.
The chart below shows the light cloud cover and the sky temperature is representative of the sky clarity and relates to cloud coverage too. The scale is inverted to -18℃ is a cloudless beautifully clear night sky, which tonight was not!
At least there was no rain 🙂
This image below shows the cloud bank just North West of Reading that was a problem.
This next chart is from the data produced by the AAG CloudWatcher weather station. Note the sky temperature is nowhere near the -18℃ to be clear.
And finally the all sky cam just as I packed up showing the clouds clearing
Tonight I thought I would take some more images of M57 through the 12″ in OIII and then Ha. I first got the OIII filter focused at position 62,500 with a temperature of 22.42℃, I took 10 more images at 600 seconds.
Ha was then started at 00:44 after meridian flip. I spent some time looking at comet C/2020 F3 NEOWISE through 100mm binoculars with Helen, Ezri and her boyfriend Luke. Then we took some photos with the 50mm lens on the 6D.
I went to bed at 2am and left it running. In the morning I noticed I had 10 good images then the image moved due to guiding problems due to cloud.
GingerGeek and I decided to go after M57 the planetary nebula in Lyra. I had seen a lovely photo on Flickr with the outer Ha/OIII halo showing which resembled a splat of paint, taken with 9 x 1200 seconds Ha, 3 x 1200 seconds OIII and 9 x 600 seconds luminance. So we decided to go try. It would also add to my ongoing collection of Messier objects.
The resulting image of M57 was rather small as can be seen above. We initially set an autofocus run on Ha which came in at 67,213. We then focused on OIII at 67,178. After a few frames we noticed that the focus point had shifted ever-so, thus we refocused at 23:33 for OIII and to a position of 63,610.
The OIII focus exposure length was 20 seconds on a magnitude 4 star which completed very nicely. By the time we had gathered OIII for 9 x 600 seconds the clouds rolled in. We took Flats. GingerGeek ran the whole session remotely whilst I directed 🙂
Tonight GingerGeek came over for a bit of social distancing friendly astronomy along with a bottle of Malbec wine. The idea was to calibrate the AAG, specifically when it goes from Very Bright to Light to Dark and at those points what the SQM value is along with the Sun’s position below the horizon. The AAG needs to get to 2100 which is dark, light is 5 and very light is 0.
The first time we noticed the values starting to change on the AAG brightness when it moved from its continuous reading throughout the day was at 21:47 when the Sun was -3.45 degrees below the horizon and the SQM was 10.15.
Within seconds the AAG read 9 and was already on Light vs Very Light and the Sun was now -3.54 degrees below the horizon and the SQM read 10.28.
It took almost half an hour for the AAG to get to dark. At 22:16 the AAG finally reached 2100, the SQM was at 13.97 and Sun was at -6.52 degrees below the horizon.
GingerGeek had also developed a new server for IMT3 to visualise some of the data from the observatory. The Grafana dashboard charts below show the data along with the Sun altitude.
Looking at the last 24 hours shows the effect of the light nights on the SQM. The raised values after 4am went the value should be reducing or zero is the effect of a cat or bird covering the sensor. Also worthy of note is the sky temperature which shows the effect of cloud as the SkyTemperature increases. A truly clear sky would yield a value of -18℃ or better.
We also took darks on the ASC and applied them since we had never bothered to do it before. The shot below shows the before and after effect of applying the dark/bad pixel map. The whole image looks a lot cleaner and darker, although there seems to be some negative representation going on with dark pixels.
The setting that needed to be changed in the ASC software took GingerGeek a while to find.
During the daytime the ASC looked awful but remote the darkframe reference file and just applying the badpixel map seem to be better. Tonight’s set of images will show if this is better or not.
The only other odd thing that happened tonight was the dome closed without the safety setting it off. Not sure why yet ……
So I opened the dome late this evening as it was not due to be clear. However an opening in the cloud meant I could test guiding again on the 12″, especially whilst it was light in the late Spring weeks.
The first job was as always to focus which brought me to a reading of 61944 at 19.83℃.
Another small job was to sort the guider FoV out. I went ahead and used M92 to align the guider.
The final FoV settings are here for completness.
Set AS1600 to Gain and Offset 10 due to cluster being very bright and I needed to set a standard of 60 seconds minimum exposure. Gain 139 and Offset 21 gas saturated unless I selected 15 seconds, Gain 75 and Offset 12 saturated at 30 seconds so hence 10 and 10 which came in about 58k ADU.
I then performed a slew to a nearby star so I could centre the scope, there platsolve completed successfully and I updated TSX and the FoV for the 12″ with the new angle.
The first image of 60 seconds came down and was out of focus, I then realised changing the profile SGPro forgot the autofocus setting, so I had to stop the run, delete the images and set the original focus point then rerun.
Next I ran a few images but then to my horror I had the same guiding issue, where the star moves being dragged up and down in a periodic way. I slewed elsewhere and tried again and the problem did not occur. I was near M92 and just East of the Meridian and quite high up. Not sure why that is a problem.
I could not resolve, I waited a while then performed a meridian flip and low and behold the problem went away, again not sure why. I still have this terrible noise coming from the RA motor/gear area. I decided to bite the bullet and take off various caps on the scope listening and looking inside. I decided it was not after all, the through the mount cabling but coming from the RA gear itself, so I looked for the MEII guide for removing the worm block and then followed the instructions to take off the RA cover.
This gave me instant feedback on what the issue was, the belts driving the axis were making a noise. On looking through forums on Bisque.com I found a few people with similar issues and needing to grease the belts, they were told Lubriplate was a good grease. This is an American grease so I will find a similar here and then apply, I will ask Bob first for his suggestion.
So the night wore on and the LRGB frames of M92 I thought I would take whilst testing guiding progressed. At one point the imaging stopped due to cloud. I just caught the dome before it closed to change the safety sensor due to cloud. When it cleared it never really cleared, with the sky temperature reading about -14℃.
Nearing the end of the imaging session, I had caught about 15 frames of each of the filters.
The guider was behaving mostly with he odd funny jolt. By 3:30 am the sky was lightening very quickly.
By this time I had stopped guiding and imaging. I closed the dome, slewed the scope to the flat panel and proceeded to take a set of LRGB flats for Gain 10 Offset 0 and also Gain 139 and Offset 21 as request from the previous nights imaging.
It was unexpectedly clear this evening so I opened the dome late, so no cooling down.
Focus 60,279 Lum filter at 19.93℃
Slewed to Arp 286 as I had seen on Flickr and wanted to see what it looked like in 12″. I noted I needed a new set of Darks for the Lodestar off axis guider after we had changed the driver recently, so I set about taking those with PHD2.
The problem I then saw was no guide star in the FoV! I really need a rotator!!!!!
So I will image without the guider. The first image jumped as I realised the auto-guider was still on and trying to track nothing sending the mount this way and that. So I disabled and set about running 3 x LRGB for 300 seconds a piece
The first image was Luminance and looked ok, although bright due to high level cloud and no astronomical darkness this time of year. I also noted the mark on the filter caused by the LensPen! I won’t use that again. However I do expect that to come out with the flat so not too bothered. Also I could go clean it I just don’t want more dust on the filter so will leave until I have a reason to take the camera off again.
For reference here is the luminance flat.
Next up was Red filter for 300 seconds
Then Green filter
Then finally Blue filter.
So I left it to run for 3 x 300 seconds each filter. Meanwhile Mil Dave came online and opened his dome and we decided to go for a joint target to see how they compare. Given Arp 286 was below Dave’s hedge I mentioned the Coddington Nebula IC2574 which is actually a galaxy, being the object in my latest image from the travel rig with the Esprit120 and the comet passing. It has some interesting star clusters in it. We agreed on luminance and 300 seconds. Here is Dave’s result ….
Meanwhile the humidity kept rising
At just gone midnight I finished the short run on Arp 286 and slewed to Coddington to catch up with Mil Dave. First I did a quick refocus as the temperature had dropped about 2℃ since I started.
The refocus put me near but not near enough so I changed to 62,056 for a better HFR which worked. Then I went on to do Coddington and here is my result.
I had problems with unguided exposure, then had a problem finding a guide star, then the object was behind a tree!
So next I slewed to Mil Dave’s choice of object, here is Mil Dave’s image
I managed to find a guide star straight away and grabbed this
Notice my screen stretch is different hence the bright background. It is just a quick screen grab off the NUC. My turn to pick now, so went for several objects but all behind offending hedges at Mil Dave’s house. So I sent Dave off to choose one. He came back shortly with Arp 278. So off we set. Here is mine.
and of course Mil Daves….but no, he forgot to save it 🙁
So my object next, I selected one nearby to save the rather long dome rotation I just did, and the resulting loud noise when it jammed! I need to look at that. Meanwhile Mil Dave trundled his round manually. So I choose NGC 7331, also known as C30 and Herschel H53-1, so also on my list for the Herschel 400. This is what I got.
Meanwhile the cloud from the South East started to creep in and my daughter, who just came in even at this hour of 1:36 said it was foggy outside.
Dave’s grabbed the NGC 7331 below.
I was about to suggest a Sharpless object when the clouds rolled in enough for me to shut the dome. It was reading -4.8℃ sky temperature and the limit was less than 30 for overcast, so I manual overrode.
Just before it shut this is the image I got of SH2-126 which is impossible to see since it probably needs the Ha filter rather than luminance.
Well a good night all round, given we thought it was going to be cloudy it was nice to come out and play with Mil Dave and go hunting faint fuzzies, so a goodnight from me and a goodnight from him ?
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.
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 –
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.
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.
I performed a quick focus run whilst pausing the guiding and got 61836 and HFR 4.4 which is vert good for this scope.
Meanwhile the clouds from the North had started to drift in which was going to stop play 🙁
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.