DSW invited me over to the IMT3 observatory for an imaging weekend to image M101 and the recent supernova2023ixf discovery. DSW was using the 12inch RDK and I decided to put the FSQ85 on the Pegasus NYX-101 to test out the setup ready for our Tenerife trip to Mount Teide.
I ran the QHY268C at high gain mode, gain 56, offset 30 and -20℃. I finally managed to cure the noise banding I was experiencing on the QHY268C but using a fully shielded high quality USB3 short length cable that I run from direct to a Pegasus UPBv2 that sits on top of the scope.
Although it’s mid summer and the Moon was bright and approaching full the phase, the sky conditions on the first night appeared to be okay at first sight. Before processing I decided to check on data quality via the blink module in PixInsight it was obvious that they were a lot of unusable subs due to high cloud and using them would have ruined the quality of any resulting stacked image.
Running the data stack of raw images through the PixInsight Subframe Selector to analyse the PSF SNR versus noise it clearly shows that I could only use 7 frames (35 minutes) didn’t drop below 0.08 from night one whilst all the data from night two should go straight into the bin along with most of night one 🙁
Pixinsight SubFrameSelector
Given I don’t have enough data to do the end result justice due to my poor PixInsight skills I decided to invert the images – I really should subscribe to Adam Block Studios (Shout out !)
Inverted image of M101, supernova 2023ixf and surrounding area
Running the AnnotateImage Script labels the various galaxies in the image which I enjoy looking up to see which type they are, magnitude and how far away they are.
Annotated FoV for area around M101, supernova is not labelled
Zooming in to M101 to see the Supernova better, it is located to the right of NGC5461 and indicated by the two arrows.
M101 with SN2023ixf indicated by the arrows
Light Curve
The AAVSO have a light curve plotted from measurements submitted by amateurs, just enter “SN 2023ixf” and submit here. It was still around 11th magnitude on 18th June but there does appear to be a slight decline in the brightness curve.
My current setup for OSC on the Takahashi FSQ-85 uses the QHY-OAG-M and the various QHY metal spacers which you screw through the OAG onto the CAA that fronts the QHY286C.
However, I’ve never liked the screw adapter approach for this sensor as unnecessary back focus is wasted due to the weird CAA to QHY286C not being a screw thread. The lack of an IR cut window on the QHY268C sensor means I need to sit an additional filter in the QHY 020055 M48 (F) adapter, in order to change the filter I would have to take the imaging train apart to remove it !!!
Baader Universal Filter Changer
Enter the Baader Universal Filter Changer (UFC) , the chart below details the core base changer alongside the adapters required to match to most common setups.
You can purchase additional sliders than can hold 50mm, unmounted and threaded 2 inch (M48) filter. The slider is magnetic so it will not dislodge during slews or during scope assembly or disassembly.
The 4 assembled components of the Baader UFC
Proposed Set-up
The Takahashi Flattener (TKA37582) has a metal back focus distance of ~56.2 mm so I need to get close to that but being under that distance is better than being over as I can add additional spacers if needed. The effect of adding a 2mm thick 2-inch filter decreases the optical backfocus by 0.6mm (2mm/3) so I will need to add 0.6mm spacing to account for the filter effect which results in a total distance of ~56.7mm.
Order
Component
Thickness (mm)
1
QHYCCD QHY268C CMOS
17.5
2
QHYCCD CAA M54(f) (#020002)
6
3
Baader UFC M54(m) camera side adapter (#2459117)
2
4
Baader UFC base (#2459110)
13
5
Baader UFC SP54(m) telescope side adapter (#2459134)
1
6
QHYCCD OAG-M M54(f) (#020079) adapter
3
7
M54 Metal Spacer
0.5
8
QHYCCD OAG-M
10
9
QHYCCD Metal Spacer
0.4
10
QHYCCD OAG-M M54(f) adapter
3
11
M54 Metal Spacer
0.3
12
Baader M54 x 0,75 Inverter Ring
0
Total
56.7mm
New Imaging Train
I should now be able to change filters much easily albeit at an additional cost but the flexibility should be worth it. Of course I will need to test the star shapes in the field to make sure that I have the correct back focus and add extra distance if needed.
Vendors
The majority of the Baader UFC components were purchased from FLO (First Light Optics) and the remaining adapter (#2459134) from Tring Astronomy. Delivery and communication by both vendors was great, shame about the Royal Mail industrial action messing deliveries about during the Christmas holiday.
Thanks
My gratitude to Stuart1971 from StargazersLounge who helped me with suggestions to try to sort out the QHY268C noise banding issues.
As it was a work night and Dave was working I was imaging from the back garden and not the dark site. I started late in the evening and had issues sorting out the autofocus in NINA which meant I was even later than I had planned.
Using the OptoLong L-Pro filter and the native camera driver (not ASCOM) :
QHY268C Nina Native Mode
The target was decided by Dave as M31 (Andromeda Galaxy), I decided on 120 second exposures at -15℃, gain 0 and offset 30 (Photographic Mode). I finally started to capture data at 19:55 when M31 had already transited 45 minutes earlier.
M31 single sub (stretched) via NINA Imaging Session
I believe the dark shadow to the left is the QHY OAG prism, I may have to reduce it’s depth in the light path or rotate it 45 degrees so it sits on the long horizontal axis.
Once M31 had reached approximately 50 degrees altitude and was starting to set in the West my guiding started going awry especially in RA. I put this done to either balance issues or cable snagging so that’s something I need to look at in the future.
After shutting down earlier than I thought due to the guiding issue and the pending rising Moon I decided to do my darks, flats and dark flats. However my Pegasus Flatmaster refused to connect to NINA so I decided to fix and complete this task on a different day.
I only managed to capture 62 subs which totals just over 2 hours. I was hoping to get at least 6 hrs for a single session and something approaching > 12 hours which means I will need several more nights to capture my required amount of data for M31.
Not a great first outing but given I hadn’t imaged in ages this was expected. I can honestly say that although a OSC coupled with the new harmonic mounts such as the ZWO AM5/Pegasus Nyx are very convenient as part of a lightweight holiday travel setup. OSC also is easier processing but still I can say I’m not a total fan due to the loss of high frequency data, high HFR focus issues and in the case of the QHY268C the noise banding issue which although appears to be removed by darks etc still is unnerving.
Update (17/12/2022)
Have resolved my Flatmaster 120 panel issues but I feel I’m better off with a fully controllable fixed panel instead of a manual panel so I will look into that.
My Darks, Flats and Dark Flats are now done (25 of each) all performed at -15℃ to match this session temperatures but there is still not enough actual data to start processing.
Unusually it was a clear Friday evening. I did plan to be ready to go as soon at the pole star was visible but my imaging PC insisted on updates and the local hard disk was running at 10MB/s (replacement SSD on the way).
By the time I was ready, mount setup, polar aligned and balanced it was already late. I decided not to use the latest SGPro or NINA beta but just use the existing SGPro version. I was delayed starting as I was having issues with SGPro hanging when it couldn’t talk to the SQM (ASCOM Conditions Observing Hub) on a previous COM port, I need to report this back to the devs as a bug.
At this point Peg-Leg Dave joined me on a video call and we discussed imaging M45 in different modes on the QHY268C OSC. So we moved the scope to Alp Ari and proceeded to plate solve in SGPro, sync’d the scope Cartes Du Ciel and calibrated OpenPHD2.
Using the SGPro framing and mosaic wizard to decide on the framing for the target sequence I wanted as much of the reflection nebula as possible rather than being dead center.
M45 – SGPro Framing Wizard (FSQ85/QHY268C)
I’ve used the multi-star guiding in OpenPHD2 since it was first released in an earlier beta and I know Dave is looking forward to using it when he moves from using an OAG on his 12-inch RC to a 90mm guide scope to make it easier to get more guide stars or even one star.
Multi-Star Guiding in OpenPHD2
Whilst trying some mode/exposure tests the guiding started acting up in RA, so parking the mount and disengaging the clutches I redid the balance of the scope. It was only marginally off but it was enough to cause issues for the CEM60 …. it is not forgiving !
We decided to increase the Gain/Offset to 15/75 and use the Extended Full-Well mode (#2) of the QHY268C, testing the star brightness levels of various exposure times we opted for 180 seconds as that was under the maximum brightness level.
As I currently have no IP camera outside I like to see the mount position using GSPoint3D as I like to view where it is especially during meridian flips. NINA has this built-in now in the recent version 2.0 betas. As SGPro lacks this functionality I can use the view via this is standalone version that connects to the ASCOM mount.
Mount/Telescope virtual viewM45 – Pre Meridian Flip
SGPro paused the guiding just prior to the meridian flip. Following the automated flip, the guider and the imaging sequence automatically restarted after a plate solve and auto centering were performed.
Inverted shot of M45 (180s) – Post Meridian Flip
It gradually got cloudier just after midnight and the quality of the subs declined so I decided to stop acquiring data even though we really wanted over 4 hours of exposure.
I proceeded to take calibration frames. Using a target ADU of ~23,000 the SGPro flat wizard on the Pegasus FlatMaster (100%) gave an exposure time of 9.68s for the Optolong L-Pro filter, 25 flat-frames were taken followed by 25 dark-flat frames of the same exposure time and finally 25 dark frames of 180 seconds.
It was at this point that I realised that the FITs header showed a gain level of 0 and not 15, the offset was correct but I can’t be sure if the EFW mode was used as it’s not in the FITs headers. Only when using the native driver in NINA can you set the mode within the sequence, in SGPro the mode is set in the external ASCOM driver when the camera is not active in SGPro even though though it’s in the ASCOM API as the Camera.ReadoutModes property.
Also for some reason the default setting in the QHY driver is to NOT disable the overscan area which means I have black borders on my images which will make processing the data in Pixinsight a challenge !
I actually got to bed after 3am even though I had planned to stay up until the dawn. Next morning I noticed that my counter-weight had slipped and rotated on the bar. This may have also caused some of the issues with the guiding so I need to set-up earlier and check things more thoroughly in future to avoid these mistakes.
So although it’s not the data we planned it will be worth processing over a wine. The evening was a really a useful experiment and hopefully lessons will be learned …. if I remember the next time.
I’ve taken the plunge and dipped my toe into the CMOS world. Since I didn’t have any OSC experience I chatted with DSW (has a QHY186c) and decided on the QHY286C. This I purchased from Bern at ModernAstronomy who has always provided excellent service.
The issue with APS-C sensors when coupled with the Takahashi FSQ85 is that the edges start to show signs of star elongation, I already see this on my Atik460. This can be corrected with the FSQ-85 flattener (ordered from FirstLightOptics) which has the effect of slightly increasing the focal length but also reduces the back focus from the native 197.5mm to 56mm.
Effective Focal Length
455mm (f/5.4)
Image Circle Diameter
44mm
Metal Back Focus
56mm
FSQ-85 EDX with Flattener 1.01x
This means that I can’t use my existing Atik OAG->Atik EFW2 and Atik460 because it’s total distance is 59mm (22mm+24mm+13mm) so it’s out by 2mm even once you include the filter effect on the back focus. Note – This is also true for my Starlight Xpress configuration.
I do not understand why Atik could not have got to within the 55-56mm range by shaving off a mm here and there 🙁 I may need to replace all Atik gear when I convert to mono CMOS or replace the OAG with a guide scope.
So onto the QHY268C, the OSC CMOS unfortunately has a CAA tilt adapter instead of a direct thread connection. This wastes 11mm of precious back focus giving a total distance of 23.5mm whereas the recently released QHY286M CMOS has a 12.5mm back focus !!!!
Also the QHY268C does not have an IR/UV cut filter in place so you need to buy an additional filter and holder and add that to the cost and factor in the adapter and distance needed …. I’m starting to regret this purchase more and more !
Source – QHYCCD.com
Back to the Takahashi Flattener (TKA37852), the back focus is 56.2mm but we add on the filter thickness as it changes the light path (2mm/3=0.66mm) so ~57mm (56.9mm), the imaging train is as follows :
Adapter
Distance (mm)
Accumulated Distance (mm)
Connector
OU031
2
2
M54(M) -> M54(M)
QHY 020770
4
6
M54(F)
QHY Spacers
14.4
20.4
screw
QHY OAG-M
10
30.4
screw
QHY 020055
2.5
32.9
screw
inc filter
0.6
33.5
–
QHY CAA adapter
6
39.5
screw
QHY268C CMOS
17.5
57
screw
FSQ85 Flattener to QHY268C imaging train
The combined weight is 1365g so I may need to adjust the balance of the scope a little as it heavier than my Atik460/EFW2/OAG setup at 1080g.
Completed – Imaging train ready for first light
I may have to adjust the spacers a little but I won’t know until I have received a 2-inch Optolong L-Pro light pollution filter which is currently on back order from FLO.
Transmission chart for Optolong L-Pro
QHY268M
The recently released mono version of the QHY268 looks like it has a proper screw face plate with a more acceptable back focus of 12.5mm. This is more reasonable and would allow me to couple a filter wheel and OAG as well not requiring a IR/UV cut filter.
Like SyedT on StarGazersLounge I could go back to using a guide scope and ditch the OAG and then the imaging train could incorporate a rotator :
I was thinking of a rotator for the remote Esprit120 which has a generous back focus of 76mm so I should have no problems there but that will be another adventure for the future !
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.
