Imaging session: NGC 7822 and the mystery of the unplanned meridian flip

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 Imaging Session Report: NGC 7822 and the Mystery of the Unplanned Meridian Flip

Astrophotography has a funny way of keeping you humble. Some nights everything aligns perfectly; on others, the universe seems to shrug and say, “Not tonight.” This was very much one of those nights.

In this post, I’ll:

• Introduce the deep-sky object I actually captured
• Outline my original imaging plan
• Break down what went wrong (and why)
• Share my post-processing workflow based on the data I managed to collect

Think of this session as a road trip where the satnav fails, the fuel gauge lies, and you somehow end up discovering an interesting town you never planned to visit.

A Confession: This Wasn’t the Target

Let’s start with a confession.

NGC 7822 was not my intended target.
I had planned to image IC 1805 – the Heart Nebula, but plate solving simply refused to cooperate. No matter what I tried, the mount and ASIAIR stubbornly kept slewing to the same location.

Eventually, after two hours of wrestling with software, cables, and my own patience, I gave in. The system kept defaulting to NGC 7822, so I accepted the hint from the cosmos and went with it.

Accidental target? Yes.
Regret? Surprisingly, no.

What Is NGC 7822?

NGC 7822 is a vast emission nebula located in the constellation Cepheus, right on the border with Cassiopeia. It’s a challenging object visually - like trying to spot mist in a dark valley - but long-exposure imaging reveals its dramatic structure.

This glowing star-forming region sits at the end of a giant molecular cloud, approximately 3,000 light-years from Earth. It’s a stellar nursery, quietly shaping new suns while we struggle to point our telescopes at it.

Object details:

• Right Ascension: 00h 01m 28.35s
• Declination: +68° 42′ 43.2″
• Magnitude: +8.0
• Apparent size: 60 × 30 arcminutes

Astrophotography Equipment Used

For transparency (and troubleshooting), here’s the full imaging setup:

• EQM-35 Pro mount
• William Optics Zenithstar 61 II with 61A field flattener
• Canon 800D (astro-modded)
• ASIAIR Mini
• ZWO 120mm Mini guide camera
• RVO 32mm f/4 guide scope
• Optolong L-eNhance clip-in filter
• Celestron Lithium Pro power pack
• Three 25,000 mAh power banks
• Dummy battery for camera
• Two dew heater straps (main scope and guide scope)
• MSM green laser pen (polar scope alignment)
• Google Pixel 6a smartphone
• Samsung Galaxy A9 tablet (used as a light panel with a homemade sleeve)

Setup and the Battle With Plate Solving

After a rough polar alignment earlier, I balanced the rig in RA and Dec, powered everything up, and launched the ASIAIR.

Finding IC 1805 proved almost impossible. It was nearly at the zenith - an awkward position that made accurate slewing and plate solving unreliable. Each attempt snapped back to NGC 7822 like a compass needle refusing to point north.

From setup to surrender took two full hours. My imaging window - before clouds rolled in - was limited to 18:30–00:15, and by 20:00 I still had nothing running. Motivation was draining fast.

Eventually, I stopped fighting it. Guiding calibration went smoothly, and imaging finally began.

Environmental Challenges: The Odds Were Stacked

Several factors conspired against this session:

🌕 Moon and Location

With roads dangerously icy (nine car crashes on my road in two hours—including a police car), I stayed in the back garden.

Unfortunately:

• A steep, wooded slope blocks the southern sky
• The house blocks the north
• My usable sky runs north-west to east, above 70° elevation
• The site is Bortle 5
• The Moon was 96% full

Trying to image faint nebulosity under these conditions is tricky, is it not.

Imaging Plan (That Mostly Didn’t Happen)

After test shots, the plan was:

• ISO 800
• Bulb mode
• 300 seconds × 40 lights
• 20 darks
• 20 bias frames
• 20 flats

Reality, however, had other ideas.

Seventeen light frames in, power problems began.

Power Failures and a Rogue Meridian Flip

Both the camera power bank and the main mount power source started losing charge—despite being fully charged that morning.

Fifteen minutes later, the mount performed a completely unscheduled meridian flip, even though the ASIAIR indicated several hours remaining. It was like watching my car suddenly turn around on the motorway because it thought I'd missed a junction. 

Possible Causes: ASIAIR Issues

I’ve only experienced ASIAIR problems once before. These are the likely suspects:

• The mount and app were not properly synced
• Incorrect latitude or longitude was entered 
• The app may have mistakenly believed it was in the southern hemisphere

Any of these could explain the premature meridian flip.

Possible Causes: Power Bank Failures

For the first time, I wrapped the power banks in loose bubble wrap to protect them from temperatures dropping to –3°C. They were attached to the steel tripod legs using 3D-printed clips.

Possible explanations:

• The bubble wrap caused overheating
• Cold air pooled around the tripod at the base of the slope, draining batteries faster than expected

Cold behaves like water - it flows downhill and collects where you least want it.

Post-Processing Workflow

Given the limited data, processing was kept simple and efficient.

Affinity Photo

• Stacked 17 light frames
• Curves and levels to restore colour balance and exposure

Siril

• Background extraction
• Plate solving
• SSPC colour calibration
• Veralux Hypermetric Stretch
• Cosmic Clarity denoise
• Cosmic Clarity sharpening

Final Touches

• Minor contrast and colour tweaks back in Affinity Photo

I’ll share a more detailed workflow later this week.

Final Thoughts: Lessons From a Difficult Night

Not every astrophotography session is a triumph - but every one teaches something.

If you have thoughts on:

• What I may have done wrong during mount setup?
• Why the ASIAIR behaved unpredictably?
• What might have caused the power failures?

… please leave a comment below. I’d love to hear your insights.

Thanks for stopping by. I hope you found this post useful, reassuring, or at least relatable.

Clear skies, stay safe, and happy astrophotography,
Steve 🌌

Technique tutorial - how to set up a meridian flip on a ZWO ASIair Mini

 Blogger isn't always the most intuitive platform to navigate - but it is free and simple to use and manage. 

To help you find information quickly on this blog, you can

• use the search bar using key words e.g. Asiair mini
• use the blog menu list by date 
• use this page which will be regularly updated https://undersouthwestskies.blogspot.com/2025/12/want-to-find-something-quickly-on-my.html

How to Set Up Meridian Flip in the ASIAIR Mini

My experience of Meridian flips using the ASIair Mini and my EQM – 35- PRO mount has not been a good one thus far – twice I’ve failed to get a meridian flip to work. However, a few nights ago I saw what it should look like and gained some useful tuition from WA Emery, when we were both imaging down at Wembury.

So, in this post, I go through

·       What the meridian flip is

·       What you need to check before programming one into your ASIair

·       How to make the settings changes

·       What happens during the flip

 

Let’s get stuck straight in then:

A meridian flip is an automatic manoeuvre that slews the telescope to the opposite side of the mount when the target crosses the North-South meridian; preventing a collision between rig and mount and continuing your imaging session safely.

 

Before you start, make sure:

·       Your mount supports GoTo and ASCOM/EQMod protocol when used with ASIAIR

·       Your mount is correctly balanced on both sides

·       You’ve done a successful polar alignment

·       You’ve checked that plate solving is working and is correct

·       Your time, location, and mount parameters are correct in the ASIAIR app

To program the flip:

·       Connect Your Mount in ASIAIR as normal

·       power everything up and open the ASIair app

·       Connect the ASIAIR Mini to your mount (via USB cable or WiFi depending on mount).

·       Confirm mount is set to "Equatorial" mode.

 

This will all ensure that your ASIAIR knows the mount’s exact position and orientation to calculate when the meridian will be crossed.

 

To enable the Meridian Flip in the app:

 

·       ASIAIR App → Mount → Meridian Flip Settings (may be AMF – auto meridian flip)

·       Toggle AMF to on - This tells ASIAIR to monitor the mount’s RA position and automatically execute a flip when needed.

·       Enable Auto-Guiding Interaction – mount – flip settings menu – ‘stop guiding before flip’ - you need to enter the number of minutes you want to stop guiding before the flip – I normally do it 3 minutes before the flip time – which you can find at the bottom of the app screen. Your ASIair app and mount will work together now to identify when your imaging object will cross the N/S meridian – and it will stop the guiding (but not the tracking) X minutes before hitting the meridian line.

·       “Do AMF X minutes after Meridian” – this is how long you want your mount/guiding to wait after passing the meridian before slewing to target once more, plate solving and resuming guiding and shooting images.

Next:

·       “Recalibrate After Flip” is optional (usually not needed with high-quality mounts) but I do it because it prevents guiding from fighting the flip and ensures post-flip guiding resumes cleanly on the opposite pier side. Again, enter a time for when the mount/guiding will resume after the meridian flip.  

Points to note:

The bottom of your screen shows the time to elapse before a meridian flip is required.  I always watch my meridian flip to ensure no cables snag during the process. Remember, if your imaging exposure time risks crossing the meridian flip time, the ASIair will stop imaging before the flip so that you don’t get a partial image. This means it could be a lengthy wait before things resume the other side of the flip – e.g. 3 mins stop before flip +cancelling a 5mins exposure+ 5mins after flip+ restoring guiding and plate solving – you could lose 15 – 20 minutes of imaging time for the whole process to complete.

 

When you have entered your settings, all you need do is then start an imaging plan or autorun as you’d normally do.

Once started, the ASIAIR will display a Meridian countdown beneath the mount info (e.g., “Meridian in 32m”). The flip will only occur during an active imaging session.

 

What Happens During the Flip (Automatic)?

 

When the flip moment arrives, ASIAIR will:

·       Finish the current exposure

·       Stop guiding

·       Slew the mount to the opposite side

·       Plate-solve to re-centre your target

·       Restart guiding (with/without recalibration based on your settings)

·       Resume imaging

 

I hope this helps – this is the crib sheet for my next outing to ensure I haven’t forgotten to do anything. I will let you know how I get on.  You can find another tutorial here about the ASIair Mini which I wrote back along - https://undersouthwestskies.blogspot.com/2025/02/beginners-guide-to-using-autoguiding.html

In the meantime, as always, if I have forgotten any stages, got anything wrong or you just have some further tips to make a meridian flip experience better, do drop a comment below so we can all better learn.

Clear skies, stay safe and have enormous fun as always

Steve

PS I found this video useful

https://www.youtube.com/watch?v=nOZFmxMBbZM

Discussion: Lost in Space and Meridian Flips

First visit to this astronomy/astrophotography blog? Well, firstly a warm welcome to you and thanks for stopping by. After reading this post, if you want to find out more about me and this blog, why not visit my introductory page at https://undersouthwestskies.blogspot.com/2025/01/welcome-to-my-new-astronomyastrophotogr.html You can also browse other posts by using the search bar or the blog post list on the right hand side and I'd really like to hear from you via the comment boxes. Drop me a tip, an observation or a question. Take care and clear skies to you. Steve

 Astrophotography is a funny old game isn't it. Take last night. Target IC 4604 - The Rho Ophiuchi complex. 

My best ever polar alignment and set up times. A clear sky, faint breeze and a 37% moon. The tide almost in and breaking over the rocky foreshore below the car park. The distant rhythmic flash of the Eddystone Lighthouse and far out in the English Channel, lit up ships passing in the night. 

ISO 800, 240" x 20 plus calibration frames. My little radio tuned to Radio Four and then The World Service. My primus stove hissing and bubbling away away when I felt the need for a warming cuppa. 

Astrophotography and astronomy have taught me much over the last few years about the night sky, how to use my cameras, mounts and telescopes/lenses; and of course imaging techniques. A newly found passion for astronomy, astrophotography and art! And all the time, I have been developing my scientific knowledge, use of technology and problem solving thinking. My son-in-law has even ignited within me an interest in 3D printing and the potential it has for creating little helpful bits and pieces for my various astronomy/astrophotography rigs. 

As a person, I have developed more. My patience is much better! My concentration and focus back to pre-retirement levels! And my blood pressure? So much lower! Out at night, under the stars, I am relaxed, pondering, reflecting, asking some big questions, just tuning in to a radio programme I wouldn't have likely heard had I not been up at that hour! 

My friends would say that I've become even more nerdier than I was and that isn't a bad thing at all. I can chatter away about the night sky forever! 

But then it isn't all rosey is it! 

I keep 'hitting a wall!'

One wall is using SIRIL and Generalised Hyperbolic Stretches. I have watched all the Youtube videos. I've taken notes. I have practised and practised - to no avail. I am still none the wiser! 

Another 'wall' is using the ASIair plate solving.  

How did I miss Rho Ophiuchi? I mean how? On my screen in plate solving it was clearly identified and central. When I did the sky atlas stuff - it synched correctly. 

But, as you can see, all the bright cloud colours - where are they? I missed my target! By quite some way! Unbelievable! I am laughing about it - serves me right and a lesson learned. Check that I have the right co-ordinates in RA and Dec! 

Plenty of 'cloud and dust' stuff

ISO 800  240" x 20 

20 of each calibration frame

Canon 800D, Zenithstar 61ii with field flattener 61A, EQM-35-Pro mount, ASIair mini, RVO 32mm guide scope with ZWO 120mm mini guide cam, Celestron Lithium Pro battery pack 

Processed in SIRIL, GraXpert and Affinity Photo. 

If you can identify where in space I ended up in this shot, I'd be grateful! 

Conclusion 'Lost in Space' somewhere! 😕😩😆

Meanwhile here is my third 'wall'. How do you perform a meridian flip on the EQM35PRO using an ASIair mini? 

I thought I had the right settings last night and it sort of performed a flip but the cables twisted and wrapped themselves around the mount and so when guiding restarted it was shambolic. I ended up doing a manual meridian flip; after I had unplugged various cables to ASIair mini and my DSLR. That of course meant rebooting everything and doing a new polar alignment. 🙄

It is hard work being a newbie and novice isn't it 😉😆

If your gear hasn't don a meridian flip yet and you are using guiding with an ASIair - here are two helpful videos that explain the process