After a day out it is unexpectedly clear. So after being notified as such from some friends at Basingstoke Astronomical Society, I opened the dome and uncovered the 22″.
I set the 150 Esprit in the dome running on M57 again to grab some more data as the night before. I do like to have at least 4 hours on each object now.
M57 6 hours of 72 x 300s
I then started cooling down the 22″ for the specific purpose of viewing Saturn at around 2:30am.
At 2:30am I started viewing Saturn.
I needed to move the scope back away from its usual place away from the Workshop as Saturn was behind the roof. I used the 31mm Nagler to start with, Saturn was fairly small but crisp in the FoV. I then swapped to the 13mm Ethos, refocused and Saturn appeared much larger, however the detail came and went with the seeing. Saturn was pretty low at this point, only 23º above the horizon. The rings were clear and obvious, the Cassini division easily seen between the A and B rings. I could not make out any surface detail. I spent about 20mins observing with my observing chair which was very pleasant on this summers night at 14º.
I finally looked at Neptune at 3:20am. I star hoped from Omega Pisces down towards Neptune.
Screenshot
I could just make out Omega Pisces in the night sky due to the approaching dawn. Neptune was extremely small but an obvious planet rather than a star.
Screenshot
Finally here is a crop of M57 and the galaxy IC 1296
This evening I have chosen another Messier object as I try to completed my list. M57. The Ring nebula is very small and as such appears small in the Espirt. I did want to get this with the 12” before I sold it but never got around to taking a great photo. Instead I will image with the 6” and zoom in.
Full screenZoomed In
The Seestar is also out, this time I have removed the tripod and thus it allowed me to perform a mosaic of the Milky Way. It is not immediately or at all obvious how to decide which bit of the Milky Way to mosaic, however I will go off and find a YouTube view. Meanwhile I have started the mosaic based on a random placement of it. I found the outcome to underwhelming to say the least. The total exposure for each frame in the mosaic was 10s of seconds and I could not seem to find a way to increase the total exposure or frame count.
Tonight I have the 150 Esprit in operation and the Seestar S30 Pro. I am imaging M56 again with the Esprit to gather an additional 1.5 hours of data.
On the S30 Pro I started with a Milky Way shot, It was meant to be the mosaic, however the scope was on the wedge and the mosaic only works when not using the wedge. So instead I went for a single image. Clearly seen is the cloud in the distance.
Once this was completed I went to image the Lobster but landed up on the Bubble instead. So I imaged that until 3am at the end of darkness as it is.
Tonight was about using both the 150 Esprit from the observatory and the Sky-Watcher 180 Mak outside. I setup before darkness fell and then proceeded to send the 150 Esprit to image M56, one of the Messier objects I had still not imaged. I decided on 120s exposures and in the end took 90 of them, with a handful or so having to deleted due to movement issues, probably when I stood next to the pier.
M56 120s Exposure
The dome would not rotate at sidereal tonight. Every time I set it to 1x sidereal it would after a while run away and just keep turning. This meant I had to manually move the dome every 15mins or so during imaging.
With the Sky-Watcher 180 Mak I imaged Saturn. This time I caught it before 3am, but I also managed to work out how to use the ADC and apply colour channel shift before saving the image.
Saturn best 30% of 8,000 frames
Whilst I had a lot of frames and the colour shift is much better than the other night, the seeing was not as good tonight. The Jet stream is still out of the way, however the air was very turbulent, thus the gap in the ring cannot be seen as well tonight.
I uncovered the scope to cool it down and then went to bed until 1:30am. I then got up and went out to image Saturn which would appear around 2:30am from behind my Oak tree. The outside temperature was still 19ºc so pleasantly warm.
Temp from Air Source Heat Pump sensor
I will attempt to capture the charts for the Jet stream from net weather.tv, and the charts for cloud cover, transparency and seeing from skippysky.com.au both excellent sources of information for lunar and planetary imaging. As can be seen below it was a perfect night.
Jetstream – netweather.tv
Total Cloud Cover – skippysky.com.auTransparency – skippysky.com.auSeeing – skippysky.com.au
I had many challenges. Not least adjusting my polar alignment that had shifted slightly since the previous night out. I then struggled for an age to get SharpCap to plate solve, finally realising that it was due to being out of focus!
Once focused it was easier to polar align. I did need tonight to rack up the exposure to 37s to do so, so I must go back and look at my original settings from my other session and compare.
After that I could get Saturn on the chip after a manual spiral search and Saturn was only slightly misaligned on the OTA and I started imaging.
Saturn 3:50am using SharpCap
Here is a video of one of my capture sessions.
Raw video of Saturn
The settings I used were based on hitting Auto sharpen and then adjusting slightly. I did try Auto sharpen more but this was too much.
Sharpening & Adjustments
This means you go from this unsharpened image to this sharpened one. So much better but I could get better focus and improve my use of the ADC.
Unsharpened SaturnSharpened Saturn
I then took the tip from Mark Radice and set the stack to only use the best 30% of frames and just drop the rest.
Best 30% of frames stacked
Once this was done it was time to head back to bed at just gone 4am.
Saturn right of the Moon, the steak on the right is a plane
Luke and I setup the S30 Pro with the Antlia Triband RGB filter to see what difference it makes.
Meanwhile I have taken the Telegizmo cover off the 180 Mak ready to go after the Moon at midnight and Saturn again after 2:30am.
After waiting for the majority of the “night” as it is, at 10 past 1 I slewed to the Moon and started to image using SharpCap 4.1. The image was not great as the seeing due to the Jet stream being overhead was not ideal, but it gave me a start on re-imaging pieces of the Moon. I managed to at least grab a single stacked image of the 3 large craters at the edge of Mare Nectar’s, namely Theophilus, Cyrillus and Catharina.
Bottom left to top right of the crater chain – Theophilus, Cyrillus and Catharina
I must admit to having problems with remembering how to use the ADC so I will watch a video over the next few days.
Meanwhile the S30 Pro also struggled under the not dark skies but again produced an ok image given the lighting conditions.
I setup the Sky-Watcher Mak 180 this evening to make sure I could get everything working on the new ZWO AM3 mount ahead of starting my imaging on Saturn and Jupiter along with the Moon.
First I had to install a new battery box inside Telrad as the previous one had split. Once completed I installed on the top of the OTA. I setup next to the observatory on the step to give some height. Later in the evening it was apparent from this position I could see objects including the Moon and planets appearing above the Oak tree across the road at around 00:15am at an altitude of 8º near the ecliptic.
Based on the above I estimate Saturn will be visible possibly around 3am. Until then I will continue to refine and test the system.
I opened the Windows laptop I have for astronomy and started SharpCap v4 from Robin Glover. This looks to be a fantastic piece of software, not only for capturing lunar and planetary images but also for automatically processing them using the Live View. It has come on a huge amount since I last used the software.
It now also has a polar alignment built in. This transpired to be fantastic. It is automatic and works on plate solving. So once I got focus, I switched to PA starting in the home position pointing to just near Polaris and clicked start. After a few screens and a little adjustment I was there.
I then slew to Arcturus but it was definitely not on the screen. I must have been close though as the scope looked to be pointing in that direction. I found Sharpcap had a plate solve feature which undoubtably is what is used during PA. I found the star it was pointing at.
I looked at Sky Safari on my phone and found Arcturus was next to this. I moved the mount using the Sky Atlas app on my phone that comes with the ZWO AM3 and Arcturus slewed into view. I synced and was good to go once the Moon rose.
Soon the Moon rose and at full chip resolution it still did not fit in, however given the suggestion (the best one I have heard in a while) from Robin Glover was to ditch the planetary camera I had from ZWO due to the small chip, and instead use one of my deep sky ZWO cameras, so an ASI 2600MC for me, this made finding stars, the Moon etc so much easier.
I then used the Region of Interest feature to zoom into the Moon. You can see how grainy the original unstacked image is.
Then I confirmed the settings for the stack and for set to live view the Lunar surface. The menu option for this was under Tools rather than the Live View on the quick link bar. A small stack of the ROI gave the following.
This was not bad given the currently low altitude of the Moon but also the Jet stream being overhead as detailed on the brilliant weather website SkippySky.Com.Au
Screenshot
The cloud cover, transparency and seeing were excellent tonight, however with the jet stream being overhead the air was just bumping around too much.
At 2am Saturn was still behind my own oak tree.
Finally at 3am Saturn appeared out the side of the oak tree.
I need to understand how to adjust the ADC correctly as it was definitely not easy. Also I need an EAF as manually focusing makes the planet wobble too much.
One of the problems I did have was thinking I was adjusting the gain on the image when I was actually just adjusting it on the screen rendition. This meant I was underexposed on what I was capturing.
The planet looked tiny on the APS-C chip
By 3:35am the sky was visibly bright and my practice session came to an end.
I had been seeing a small problem with the Seestar S30. I noticed on holiday that the top left corner looked out of focus. I contacted the brilliant ZWO support and they suggested it might be a focus issue in that it was not focused properly. Tonight I thought I would refocus and take some more images to see. This is what I saw.
As you can see the image is almost perfect. Much better than the affending stars from the trip up Tenerife’s mountain Teide recently. Problem solved. It had clearly not auto focused correctly. If I see the same problem again I will simply re auto focus. Here is another of Mizar and Alcor in the handle of Ursa Major.
Mizar
Onto the other test for the night was the Canon 6D that I have and testing it again with the Samyang 14mm f/2.8 lens for use in Namibia. I set about shooting so images on the twilight sky and the stars were pin sharp.
I also liked this one with a longer exposure and thus the clouds captured in motion.
I’m out with the 22″ Obsession again doing visual. The images below are from the Moon Globe HD app on my iPhone, not focal this time. I have included as an aid to what I saw visually.
I could see huge Plato crater and Archemedeis to the top. I could make out 3 small craters, Bancroft, Beer and Feuillee before getting to Timocharis near the terminator.
I could just make out Heinrich and then Pytheis at the terminator
• ⁃ Beer & Feuillee stand out so much more. Also Montes Archimedes is very prominent and the 3 main ranges. We are in the middle of a heatwave with a very unusual heat dome sitting over my part of England. This is causing the air to be very still and thus the seeing is astonishing. The Moon is still not wobbling at all.
Mare Tranquillitatis, above Rupes Cauchy I can see what looks like the straight wall a rile going diagonally 9 o’clock to 4 o’clock and Rima Cauchy below the crater and the Hussain crater below that at 4 0’clock
Back in Mare Fecundities I can see rays coming off the crater to the right of Messier crater
In Mare Nectaris, crater Rosse is very obvious
At this point there was some cloud to the South West as the Moon was setting behind my neighbours tree
Moon 5 Days old
Time – 22:38 / Object – M106 / Eyepiece – 31mm
M106 not seen due to cloud, I could see HD 107610 though
Time – 22:41 / Object – M12 / Eyepiece – 31mm
Moved to south east near Vega where no cloud.
M12, seen with direct vision, faint against bright sky. I could see a fairly bright star to the top on the outside of the cluster. Not sure if it is part of the cluster or not
Time – 22:53 / Object – M10 / Eyepiece – 31mm
M10 seen direct vision. Slightly brighter than M12 but not prominent star. Then it got cloudy so packed up
The temperature was 17° at midnight and 80% humidity, clear and dry
Time – 22:15 / Object – Moon / Eyepiece – 31mm
Note that all observations are made North South flipped. First I viewed Mare Crisium
Picard and then Peirce and the smaller Swift crater can be seen easily
In Petavius crater you can see Rimae Petavius and a small crater to the top
Mare Fecundities you can see ripples on the floor
4 Day old Moon
Time – 23:20 / Object – M5 / Eyepiece – 31mm
5 Serpentis can be seen in the same FoV
M5 has a compact centre and I can make out a couple of prominent stars to the top right of the cluster in a line from 4 o’clock to 10 o’clock
Time – 23:50 / Object – M51 / Eyepiece – 31mm
I can easily make out M51 and the interacting NGC 5195 with direct vision, although I cannot see the connecting spiral arms. I can see some of the spiral just not extending all the way to the adjacent NGC
Time – 00:02 / Object – M63 / Eyepiece – 31mm
This spiral galaxy is seen with direct vision
I can seen a mag 11.53 star and 3 others in a line starting with Tyc 3024-1007-1
I can see the bright star next to M63 although the galaxies spiral arms do not reach out as far to it as in a photo on Sky Safari. I can see 2 faint stars diagonally placed on the opposite side of the galaxy in the plane of the disc, not sure of the names
Time – 00:17 / Object – M94 / Eyepiece – 31mm
A very bright and tight core easily seen direct vision, so much tighter than the previous M63
Time – 00:24 / Target – M86 and M84 / Eyepiece – 31mm
• Both galaxies can be seen but they are very faint. I can make out the very faint edge on spiral which is probably an NGC, however I cannot find a reference as of yet. This forms a triangle with the two Messier objects as can be seen in this screenshot from TheSkyX.
I have the travel scope setup on the patio next to the observatory. Unfortunately I’m waiting for my camera to come back from the dealer so I cannot use the 12”. So instead I have the 100Esprit ready to image SH2-129 an emission nebula with an OIII object called The Squid in front of it. I have the Askar C1 filter in place and will see if this filter which covers Ha + OIII emissions catches it.
4 Epsilon Lyra Double Double star – 31mm I can see the double but not split the 2 stars; 13mm Ethos allowed me to split the doubles and the 10mm whilst slightly dimmer afforded me a slightly wider split
Cat’s Eye Planetary Nebula – 31mm very small not quite pinpoint of light visible nicely without a filter, OIII filter makes it slightly more apparent and Nebustar filter it looks marginally better; 13mm Ethos provided brighter nebula, again the filters provided a better view with the Nebustar being brightest; 10mm is the best view of them all with a definite oval shape East or West, right to left but now OIII produced the brightest and clearest view although it is pushing the seeing tonight
Turtle Planetary Nebula – Not seen
Rasalgethi Alpha Hercules Double Star – 10mm too much for tonight, could not get good focus but could easily split; 13mm Ethos the best view with brighter primary in yellow, very striking and smaller secondary blue; 31mm Nagler just splittable but both components look yellow.
Albireo Double Star – Bright large yellow primary and smaller but still bright blue star in the 13mm Ethos
M13 Hercules Globular Cluster – lovely in the 31mm Nagler; 13mm Ethos much brighter view and obviously larger with resolving more core stars; 10mm darker background so contrast better and even brighter core and stars more obvious with direct vision, including nice pair at 10pm on the cluster
M57 Ring Nebula – planned but not attempted
61 Cygni Double Star – planned but not attempted
NGC 6891 Open Cluster in Lyra – not seen in 31mm Nagler
NGC 6702 & NGC 6703 Galaxy pair – planned but not attempted
A really good night overall, the eyepieces lent to me from Bob are excellent and make the viewing more pleasurable being able to switch with my wider field of view ones.
So the 22″ Dob is still out of action with the encoder cable needing repairing from a recent issue with snagging. I’ve ordered some RJ9 connectors to replace the one on the RA axis that is broken. So instead I thought I would open the dome and given the perfectly clear weather with no chance of rain, I would image Arp xxx with the 12″ that Bob Trevan had recently imaged with his 17″ and leave the scope running.
Due to the brightness of the sky when I started it was impossible to find a guide star, thus I have decided to perform almost lucky imaging of 1min exposures. Again given the background brightness this time of year, if I were to try lucky imaging of this faint object of say 1/10th of a second, it would not appear.
So I have set the scope running with 240 images to take in luminance and will come back in the morning and check the results.
Tonight was a visual night. GingerGeek and I used the 22″ Obsession Dobsonian to view some of the wonders of the late Spring sky.
We started with Venus with the aid of a Moon filter. Whilst Venus is bright and not too overwhelming in the eyepiece, the contrast afforded by the addition of this particular filter aids the clarity of the image as Venus sits on the bright backlight of the night sky this time of year. Venus is in a gibbous phase and you could clearly see a concave arch to the edge of Venus that was missing. The seeing was very steady and we were able to push to 179x with the 13mm Nagler.
Next up was Mars. Whilst it took a while for it to appear in the astronomically twilight sky, I swept the area North East of Venus and landed the target after a few moments. Mars was so very small compared with Venus, obviously red as seen without a filter in this case and slightly shifting in colours due to the seeing. By the time we had finished looking, Mars had appeared in the night sky.
Now the sky was getting darker we wanted to start on the deep sky objects. It became apparent very quickly there was a problem with my alignment. This was a problem I faced the last time out and the trouble is with he RA encoder. The RJ11 cable has been pulled and needs recrimping. So for tonight it was about star hoping only 🙂
We then went on to look at globulars M3, M92, planetary nebulae M57 the Ring nebula and M97 the Owl nebula. We tried to get M101 but the sky brightness would not allow it. We also looked at Mizar and Alcor that I could see from 11:30pm as a double, and we looked at Polaris and it’s double star companion SAO 305 through the scope.
The planetary nebulae were seen through an OIII filter and Tele Vue Nebustar filter. I thought the view was slightly clearer through the Nebustar filter, maybe due to the slightly wider bandwidth which includes H-Beta. The Ring nebula was very crisp and I thought I could discern the central star which is 12th magnitude. Our friend Bob was kind enough to lend me a set of eyepieces he recently acquired. The Tele Vue 10mm Radian eyepiece gives 230x through which we could see the central white dwarf.
Whilst looking at the globular clusters we pushed the magnification to 288x with the 8mm Tele Vue Radian. Both this eyepiece and the 10mm gave fantastic views with the globulars sparking with pinpricks of lights from the 1,000s of Suns!
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.
M101 for me this evening to try and get there RGB data in one night. GingerGeek has come round to test out his travel setup, he has a Takahashi FSQ85, QHY268C and the Pegasus NYX-101 harmonic mount.
Focused at 20,105 on Luminance so RGB will be 21,105
1 x 300s Red
Taking 2 minute exposures for each colour at -25℃. I then realised 5 minutes is so much better. So at 1:30am I then started exposing at 5 minutes with the plan to combine both data sets. The SkyX worked brilliantly as can be seen below, looking after the guiding and image capture.
The main challenge I had early on was the the dome shutting unexpectedly. I will attempt to find out why over the next few months. The camera noise continues to be an issue but less so tonight so I think it may be USB related, again I will troubleshoot and check there cable lengths.
GingerGeek had a productive night troubleshooting a multitude of problems on his untested travel kit and was pleased with the results including taking his first image of a supernova in M101.
Opened the dome and setup the 22″ Obsessions telescope for visual.
I have gone with a recommendation of Mark Radice this evening andI will both image and perform visual on M46 including the planetary nebula Herschel H39-4 that resides within it.
So with the 120 Esprit inside the dome imaging away on M46, now that it is to the East of the Meridian, I connected the Argo Navis to the 22″ and set about aligning the scope. After a few minutes and with the alignment complete, I pushed to M46.
M46 Observing Notes
31mm Nagler 75x Mag. M46 Open Cluster fills the view. Apparent instantly is the planetary nebula Herschel H39-4 towards the 5 o’clock position. A small ring can be seen with direct vision and with averted vision the contrast increases. I am not using any filter yet.I can resolve many stars. With the 13mm Ethos 180 x Mag H39-4 becomes much larger and you can resolve easily the star within the centre of the ring. Now only several handfuls of stars can be resolved.
M42 Observing Notes
31mm Nagler 75 x Mag. M42 steller nursary and hydrogen nebula is very bright with the wings sweeping outward. The trapezium is clearly seen. With averted vision much more gas is forthcoming around the area within the FoV. Moving to the 13 Ethos 180 x Mag the trapezium is resolved pleasantly into a much wider set of 4 stars. The hydrogen gas now takes on structure and lingering on this one can make out dark features within it give the nebula a 3 dimensional feel. Now you experience a warm glow within the eyepiece that seems to draw your eye towards the gas in which the trapezium stars sit.
At this point I cam back into there Warmroom to write up my notes and review the images being taken in the observatory. I have now taken 21 x 300s of M46. Now switching to M48.
I then joined the BAS Zoom call to speak with Derek, Nigel, Bob and Mil Dave. We discussed M44 taken by Bob and suggested if I could see the UGC 4526 galaxy. So I went out to take a look.
M44 and UGC 4526 from Bob
M44 Observing Notes
Looking at M44 with Nagler 31mm at 75x Mag…..
I landed up finishing M48 at 23:47. I took 30 x 300s but then checked through the last few when the dome closed and I actually got 26, I might have lost the guide or the dome slewed incorrectly or shut, not sure which.
Addendum – It turned out to be loosing the guide star and because the camera wears not in focus, so connecting the focuser and moving from 14000 to 21000 position fixed it. The star profile was much better and SNR was 25-30 instead of 10.
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 !
