Fun facts
CTB1 was discovered in 1955 by George Abell on the Palomar survey plates, thinking it was a planetary nebula based on its shape. In 1960 Robert W. Wilson (who later won the Nobel Prize with Arno Penzias for discovering the cosmic background radiation) and J. G. Bolton properly cataloged it as part of an early radio telescope survey. This list was known as CalTech observatory list B, hence the CTB designation. In 1966, Abell included it in his catalog of planetary nebulae (not to be confused with his catalog of galaxy clusters) with the note, “it may be a supernova remnant,” as it was already thought to be an SNR based on its radio signal. Further research in 1971 showed that CTB1 is, instead, a supernova remnant 10000 light-years away from us with a diameter of about 100 light years. Thus, CTB1 is probably the proper designation for this object, even though Abell was actually the discoverer.
Distance: 10,000 light years
Diameter: 100 light year
Constellation: Cassiopeia
Designations: CTB1, PN A66 85, Abell 85
{From https://digitalstars.wordpress.com/2022/10/22/ctb1-abell-85-the-garlic-nebula/ https://skyandtelescope.org/online-gallery/garlic-nebula/ and Stellarium}
Capture & Processing Notes
Let me start off by saying, I’m still not pleased with any of these CTB1 Garlic Nebula images. I dare say that those captured in October (when I had a full night of data collection with no technical issues or wind) were the best. This dark skies version, even though I took three (long, arduous) stabs at processing it, still leaves a lot to be desired. But, as with the framing experiment back in October, I’m sharing/documenting the full journey – the good and the bad. This target will be transferred to my 2025 collection list – when hopefully, I’ll have clear, dark skies, no technical difficulties in the fall when I have lots of dark hours and object visibility.
Having said all that – here is the capture story…
This was first light with DSO-CTRL3 – the new HP Probook control laptop purchased in early December 2024, after a week of random shutdowns with DSO-CTRL2, that HP’s (usually excellent) technical support could not help me solve. Third time is apparently a charm — just about everything was configured correctly!! Although there were a few interesting, first-time running the software set-up steps that needed to be conducted.
With the Polemaster (used the “old” SW version), I had to do the axis rotation step as there was no “previous use.” The way that the Polemaster was aligned the RA and Dec axis were reversed (that has been going on since I got the RST-300 and the screw for tightening the Polemaster onto the mount’s post needs to have the Polemaster “upside down” from its normal orientation). This caused me to have to do the rotation in Dec rather than RA to get the stars to move – but it created a good axis circle and I didn’t have to repeat that step again. (Although, now that I type this, the guiding was a little rougher than the SC on both nights, so I’m wondering if I should move the connection plate around so that the Polemaster is right-side up the next time I use it to see if that improves the polar alignment).
The start-up and running of the SGP sequence went great. I did have to reestablish the windows that are viewable in PHD2 – which didn’t “stick” until the second time I reestablished them on the screen (I’m not sure what I did differently, but after the second target of the night, they came up in the screen view that I’m accustomed too for the rest of the trip).
Putting the already assembled R&P focuser with the EAF attached on during assembly made the focusing much simpler! The autofocuser was roughly in focus, so the routine that ran prior to plate solving came to an acceptable solution. (As opposed to the SC where I had to attach the EAF during assembly – I thought I was being smart by moving it out to the position that I had marked on the SC focuser – that turned out to be a bad idea!) When I went to “fix” the SC focuser issue, I accidently connected the autofocuser hand controller to BB – and in the middle of an image – I moved the focuser to the zero position! I immediately realized my error and moved it back out to approximately where it was. I selected “Run” on the autofocus panel, which runs an autofocus at the conclusion of the current frame. I had guessed close enough to where it originally was (with the move to command) that the autofocus routine ran and got it back into focus and on its way.
The one SGP set-up that I didn’t get correct was the new version of the plate solving tab. I loaded and selected all the plate solvers, so instead of using ASTAP, SGP used Astronomy.net – which did resolve the plate solving, but took longer. After the first target, I went into the ASI2400 BB-RST300 G158 equipment profile and unchecked all but the ASTAP solvers (both the one I loaded and the “native” one that came with SGP) – and it worked fine the rest of the time.
I discovered when I came outside to do the meridian flip on the SC target, that I did have an unplanned shutdown of DSO-CTRL3 after it captured 34 images (during 19:31 – 22:32MST, 3hours of operation)! The “good” news – and the $929 lesson from the month’s long random shutdown issue – was an error message that came up when I powered the computer back up again: “The BIOS shutdown the computer to prevent overheating. Check to make sure the air vents are not covered.” Apparently, putting down a couple of placemats, putting the laptop into the felt-cushioned case, and wrapping it securely in a towel is too much! Interestingly enough, the DSO-CTRL1 laptop was snuggled up just like that and never shutdown – perhaps the BIOS “upgrade” is being more cautious than necessary (BTW – I looked up the operating temperature range for the HP Probook laptops – it is 50° – 95° – a pretty small range). So, for the rest of the night where the temperature stayed in the mid-40’s (and all of the following night, when the temperature dipped to 18°), I simply wrapped the laptop in the towel – it operated throughout the rest of the night and all the following night without issue.
The reason for the big gap in collection was because when I went to restart the sequence after powering up the laptop, the RST-300’s GPS was completely confused. (I had also gotten a message when I powered on the laptop that a “previously connected USB device was not recognized.” I started the sequence with the telescope pointing where it had been (it was continuing to track even though the laptop had powered down – so should have been close to the correct position. But, it slewed to a location nowhere near where CTB1 was! Decided to abort the sequence, park the telescope and start from a clean sheet. When I parked the mount, it moved to a position of approximately (0°, 180°) – IAW, directly pointing at me as I was standing behind the rig! I manually slewed the telescope with the iHubo controller and then disconnected all the equipment. I got out the hand controller, which had indeed lost its “GPS base.” The time came up (after a short delay, but the GPS coordinates never did. I recycled power and tried again. The second time, the time came up immediately, but again the GPS coordinates never did. I was beginning to panic – if I can’t tell the mount where it is, I’m screwed! I realized that I could establish a manually entered location and tell the telescope to use that instead of the GPS base location. I decided to try one more time to cycle the power and see if the GPS would come back to life before I did that manual location. When the power came back up in the handset, I first went into time/date to make sure that was correct – it was. Then I went to the GPS – it populated! So, I got the sequence going again at 00:36 to collect a few more images (until 00:54) before it set for the night.
The forecasted winds held off throughout the night until about 04:00MST. So, they didn’t effect this target, but it certainly wreaked havoc on the images that were being collected when the winds kicked up to the 25+ mph range! Especially with BB – I had to throw out all the images captured after 0400 because the mount and autoguider could not keep a steady collect and all the images were star trailey and out of focus.
Because of the shutdown on the night of 29 December, I decided to also start the night of 30 December collecting on CTB1 to have a larger data set to process. This image is created from the data from both night’s data collection – stacked together as a multi-session image in APP and processed (multiple times – this is version #3) in Lightroom and Photoshop.
Sequence Plan (29Dec2024): Gain: 158, Temp: -0°C, offset=30. 38x300sec. Total: 190 minutes (3:10hrs). Captured 29Dec2024, 1931MST – 30Dec2024, 0056MST and 30Dec2024, 0036 – 0056MST. (DSO CTRL3 shutdown to prevent overheating at 22:32MST. I restarted the sequence at 00:36MST until CTB1 set at 01:00MST)
Sequence Plan (30Dec2024): Gain: 158, Temp: -0°C, offset=30. 49x300sec. Total: 245 minutes (4:05hrs). Captured 30Dec2024, 18:39MST – 22:54MST (Switched to NGC2264 Cone Nebula when it rose)
Total Data in Image: 29Dec2024, 38x300sec. Total: 190 minutes (3:10hrs). 30 Dec 2024, 49x300sec. Total: 245 minutes (4:05hrs). Total = 87x300sec, 435 minutes (7:15hrs).
Processing: Captured in SGP, stacked in APP (Adaptive Airy Disc), star removal with Starnet++, processing with LR/PS
Equipment
Equipment: All equipment controlled by HP Probook running Sequence Generator Pro v4.4.1.1441.
- Imaging (ASI2400-BB-FF): ZWO ASI2400MC imaging camera on (Big Bertha) Orion 8″ f/8 Ritchey-Chretien Astrograph Telescope, Teleskop Service (TS) 2.5” Rack and Pinon Focuser M90, Teleskop Service Flattener 1.0x for RC Telescopes (TS-RCFLAT2)
- Autofocuser: ZWO EAF Electronic Automatic Focuser (EAF-5V-STD)
- Mount: Rainbow Astro RST-300 (controlled by iHubo ASCOM driver)
- Polar alignment: QHYCCD camera (controlled by Polemaster for polar alignment)
- Autoguiding: Orion 60mm Multi-Use Guide Scope with Orion StarShoot AutoGuider Pro Mono Astrophotography Camera (controlled by PHD2)
Summary
Captured: 29 & 30 December 2024. Total = 87x300sec, 435 minutes (7:15hrs).
Shooting location: Mills Canyon Rim, Kiowa National Grasslands, New Mexico
Equipment: ZWO ASI2400MC camera on Big Bertha (Rainbow Astro RST-300)
Other images of CTB1 Garlic Nebula
Capture & Processing Notes
This is a multi-sesssion image created with data gathered during five imaging sessions in late 2024. The first two were on 21&24 October 2024 – the framing experimentation with the CTB1 Garlic Nebula from the HCH front patio (described directly below – and perhaps the best image of them all!). The third session was on 29 November 2024, again from the HCH front patio, during the post-Thanksgiving weekend when I began experiencing the DSO-CTRL2 random shutdown problems throughout that session and all those during the first week in December – ultimately resulting in the purchase and set-up of DSO-CTRL 3. The last two sessions were on 29 & 30 December 2024, at Mills Canyon Rim in the Kiowa National Grasslands, New Mexico – first light with the new laptop, DSO-CTRL3 (described directly above).
Sequence Plan (21Oct2024): Gain: 158, Temp: -0°C, offset=30. 105x300sec. Total: 525 minutes (8:45hrs). Captured 21Oct2024, 1947MDT – 22Oct2024, 05:50MDT.
Sequence Plan (24Oct2024): Gain: 158, Temp: -0°C, offset=30. 118x300sec. Total: 590 minutes (9:50hrs). Captured 24Oct2024, 1916MDT – 25Oct2024, 06:02MDT.
Sequence Plan (29Nov2024): Gain: 158, Temp: -0°C, offset=30. 37x300sec. Total: 185 minutes (3:05hrs). Captured 29Nov2024, 1824MST – 2152MST (Switched to SH2-308 Dolphin Head Nebula when it rose, never processed this data on its own)
Sequence Plan (29Dec2024): Gain: 158, Temp: -0°C, offset=30. 38x300sec. Total: 190 minutes (3:10hrs). Captured 29Dec2024, 1931MST – 30Dec2024, 0056MST and 30Dec2024, 0036 – 0056MST. (DSO CTRL3 shutdown to prevent overheating at 22:32MST. I restarted the sequence at 00:36MST until CTB1 set at 01:00MST)
Sequence Plan (30Dec2024): Gain: 158, Temp: -0°C, offset=30. 49x300sec. Total: 245 minutes (4:05hrs). Captured 30Dec2024, 18:39MST – 22:54MST (Switched to NGC2264 Cone Nebula when it rose)
Total Data in Image: Total = 347x300sec, 1735 minutes (28:55hrs). {Including: 21Oct2024, 105x300sec.; total: 525 minutes (8:45hrs). 24Oct2024, 118x300sec; total: 590 minutes (9:50hrs). 29Nov2024, 37x300sec; total: 185 minutes (3:05hrs). 29Dec2024, 38x300sec; total: 190 minutes (3:10hrs). 30 Dec 2024, 49x300sec; total: 245 minutes (4:05hrs).}
Processing: Captured in SGP, stacked individual sessions in APP (HCH data (with filters) used HaOIII Color, dark skies data used Adaptive Airy Disc), then registered/integrated them together, star removal with Starnet++, processing with LR/PS
Equipment
Equipment: All equipment controlled by HP Probook running Sequence Generator Pro v4.4.1.1441.
- Imaging (ASI2400-BB-FF): ZWO ASI2400MC imaging camera on (Big Bertha) Orion 8″ f/8 Ritchey-Chretien Astrograph Telescope, Teleskop Service (TS) 2.5” Rack and Pinon Focuser M90, Teleskop Service Flattener 1.0x for RC Telescopes (TS-RCFLAT2), Optolong L-Extreme LP filter
- Autofocuser: ZWO EAF Electronic Automatic Focuser (EAF-5V-STD)
- Mount: Rainbow Astro RST-300 (controlled by iHubo ASCOM driver)
- Polar alignment: QHYCCD camera (controlled by Polemaster for polar alignment)
- Autoguiding: Orion 60mm Multi-Use Guide Scope with Orion StarShoot AutoGuider Pro Mono Astrophotography Camera (controlled by PHD2)
Summary
Captured: 21 & 24 October 2024 (HCH), 29 November 2024 (HCH), and 29 & 30 December 2024 (Kiowa National Grasslands, NM)
Shooting location: HCH, Colorado Springs, CO and Kiowa National Grasslands, NM
Equipment: Big Bertha on Rainbow Astro RST-300
Processing summary: Captured in SGP, stacked individual sessions in APP (HCH data (with filters) used HaOIII Color, dark skies data used Adaptive Airy Disc), then registered/integrated them together, star removal with Starnet++, processing with LR/PS
Capture & Processing Notes
Capture & Processing Notes (Re-framed sequence captured on 24 October 2024): This is the second imaging session at HCH to verify the reframing of CTB1 Garlic Nebula prior to imaging in dark skies. (The capture notes from the first session on 21 October are shown below for historical sake, but the image above is the re-framed version with data captured during the 24 October 2024 session.
Changes made during the 24Oct2024 session from the 21Oct2024 imaging session:
- Turned off the auto meridian flip
- Changed the EAF step size to 150 (throughout the BB/BZ equipment profiles)
Everything worked very well and the new framing (and settings) is what I will use going forward for this DSO.
This is also an illustration of “I’ve never processed the same image the same way twice!” This is essentially the same data. The big difference in the processing was starting with the STARLESS 30% stretch stacked image (vs. 20% stretch). The rest of the processing steps were pretty much identical. Another processing experiment I’d like to run on these data are to use a Hubble pallet processing – some of the images I’ve seen have done that which renders the head of garlic a shade of yellow – thus having people recognize it as a head of garlic and not a brain/brain stem! That will likely not come for awhile – there are many more pressing things on my list of things to do, including first and foremost planning and packing for next weekend’s (hopefully) dark skies trip!
Capture & Processing Notes (Original sequence framing captured on 21 October 2024): This capture was an SGP Framing & Mosaic Tool test. I’d added this DSO to my list to capture starting in October 2024, but when I planned the sequence in SGP I couldn’t see the nebula in the star field that came up at its location. I built a sequence as best I could, guessing at where the garlic head-shaped nebula was located. But I didn’t want to spend precious dark skies time capturing the area around/near or just a portion of the DSO. So, I deferred the target from my October plan until I could validate the framing during an imaging session from the front patio. That opportunity came during a few clear nights in late October (with a lot of moonlight…but that’s what the LeXtreme filter is for!).
I assembled Big Bertha (still in her case from the October dark skies trip) and set up to image on Monday night, 21 October. This was my only objective, so I imaged throughout the full night (which are getting longer!).
During the collection, everything worked smoothly at the beginning of the sequence. It was a little before 2000 when I was up and operating, collecting data on the first subframe. I sat outside and watched a couple of subframe’s collection – hoping that I would get an indication that I had the DSO in the frame…no such luck…nothing was visible in the subframes except the star field. So, I talked myself into just letting it run throughout the night – it’s only bits, it’s from the front patio, no-harm no-foul if there’s nothing but stars in the end.
I did experience one slight technical glitch… I came out to execute the meridian flip at about 2300MDT and discovered that the telescope had already flipped on its own at some point before my SGP-directed 20 minutes past the meridian (when I came out there was ~ 6 minutes to go before that point). I let it complete the subframe that it was collecting, and as expected, I got the warning: :”The next subframe’s time is longer than the time to the flip – would you like to execute the meridian flip now?” I thought…sure, why not, let’s see what it does! What it did was lock up the laptop (with another “do you want to pause before the meridian flip” warning hidden behind the main window that was precluding me from executing any commands in SGP). I finally decided to use the ASCOM driver to send the telescope to its parking position, disconnect the equipment, reboot the laptop, recycle the power on all the equipment, and restart the sequence. When I did that (thankfully) it reacquired the DSO on the correct side of the pier and went on its merry way of collecting data flawlessly the rest of the night (including the autofocuser working well!)
I’m going to have to investigate the SGP log to see what I can figure out, or ask the question to their technical support that I pay for with my annual subscription about the auto-meridian flip function. OR, just turn it off – since I always come out and supervise anyway… (which may be my short term solution!)
When I stacked the subframes, I was pleased to see the garlic head-shaped nebula in the frame! Albeit, not centered correctly. But with a little tweaking of the framing I should be all set for imaging this DSO during our upcoming (fingers crossed Mother Nature cooperates) November dark skies trip over the Halloween weekend. This is definitely a target that I want to image in dark skies. Although there’s not a lot of information or other’s images of it – it is an intriguing object worth some dedicated dark skies time to bring out the richness of its colors and features.
Sequence Plan (24Oct2024): Gain: 158, Temp: -0°C, offset=30. 118x300sec. Total: 590 minutes (9:50hrs). Captured 24Oct2024, 1916MDT – 25Oct2024, 06:02MDT.
Sequence Plan (21Oct2024): Gain: 158, Temp: -0°C, offset=30. 105x300sec. Total: 525 minutes (8:45hrs). Captured 21Oct2024, 1947MDT – 22Oct2024, 05:50MDT.
Processing: Captured in SGP, stacked in APP (HaOIII Color), star removal with Starnet++, processing with LR/PS
Equipment
Equipment: All equipment controlled by HP Probook running Sequence Generator Pro v4.4.1.1441.
- Imaging (ASI2400-BB-FF): ZWO ASI2400MC imaging camera on (Big Bertha) Orion 8″ f/8 Ritchey-Chretien Astrograph Telescope, Teleskop Service (TS) 2.5” Rack and Pinon Focuser M90, Teleskop Service Flattener 1.0x for RC Telescopes (TS-RCFLAT2), Optolong L-Extreme LP filter
- Autofocuser: ZWO EAF Electronic Automatic Focuser (EAF-5V-STD)
- Mount: Rainbow Astro RST-300 (controlled by iHubo ASCOM driver)
- Polar alignment: QHYCCD camera (controlled by Polemaster for polar alignment)
- Autoguiding: Orion 60mm Multi-Use Guide Scope with Orion StarShoot AutoGuider Pro Mono Astrophotography Camera (controlled by PHD2)
Summary
Captured: 24 October 2024. Total: 118x300seconds; 590 minutes (9:50hrs)
Shooting location: HCH, Colorado Springs, CO
Equipment: Big Bertha on Rainbow Astro RST-300
Processing summary: Captured in SGP, stacked in APP (HaOIII Color), star removal with Starnet++, processing with LR/PS