old_eyes

Waiting on new cables to check. And I will of course check with no USB hub, and alternative power supply only for the camera.

The bits you circled certainly look superficially like some of the defects I am seeing. Something to bear in mind. However, Atik have come back and said they are puzzled and asked for faulty subs, which I have just sent them. This feels like one of those journeys, gradually eliminating possibilities, rather than a jump to a solution. 😟

Carole, Just a quick question. How many desiccant tablets were in your 460ex? When I opened mine there was a single tablet that fell out very easily, but under that is another white surface that I first thought might be a wedged tablet, but now I think looks a slightly different texture and could be a barrier membrane. My observatory is not suitable for a dehumidifier. The main construction is corrugated steel and I went with plenty of ventilation to prevent excessive condensation. It has worked well. In over two years operation I have only had two episodes of significant condensation. However, it means that a dehumidifier would be attempting to dehumidify the local atmosphere. Might need to think about taking the camera off the rig when I am expecting it not be used for extended periods.

Hi Carole. Found some guidance on the Atik site for drying out a camera and regenerating the desiccant. Trying that now. If the recommend the process for users it can’t be too risky.

Thanks Carole. These are single subs - to get the 'raw' data with minimal post processing. No calibration of any sort, no stacking. Scope is an Esprit 120. I don't think it can be optical as the black points read zero. Not low , zero, total black. AN optical defect would not produce this sudden jump to zero. Out of focus stars the same. You get a smooth gradient as the 'doughnut' forms. The profile of the stars looks hideous. Sudden jumps between signal and no signal. Baffled, but hoping for someone to say - "yep, I know what this is!"

Hi, My secondhand Atik 460ex mono camera has behaved impeccably for a long time. Suddenly a couple of weeks ago it went weird, having problems downloading and showing dark halos around stars. I replaced the USB cable with another I had spare (only a cheap one) and tried again tonight. I am still seeing the same effects. I wonder if anyone recognises this This is a 60 second exposure taken with my usual Voyager configuration. A cropped section at 1:1 just STFed in Pixinsight. I tried the same exposure using Atik's Artemis capture software, just in case there was anything weird going on with Voyager. I also used NINA with the same results. I know the images are somewhat out of focus, but the autofocus routines in Voyager and NINA took one look at this, and said - Nah! No usable stars. It could be a usb cable issue and I am waiting on new Lindy Chromo cables from FLO and will test those as soon as they are here, but a bad cable has previously resulted in only partial downloads, never these curious dark rings. I am asking Atik what they think, but just on the off change someone instantly recognises the issue, I thought I would ask here as well. old_eyes

I may have misunderstood what you are trying to achieve, but why not use HDRComposition? That tool is designed for this job. It takes stacked images of different exposures and creates a high dynamic range version that allows you to see the detail from the long exposures whilst not having the bright core of objects burnt out. A standard approach for objects like M42 and M45. it is simple to use, and the tool works out which order to stack the images for the best result.

Just goes to show, you can't beat speed in a scope. Photon flux may not be everything, but it is a hell of a lot of the story. My latest attempt at this target took (cough) three times as long! Alternative final processing of OSC Rosette - Imaging - Image Processing, Help and Techniques - Stargazers Lounge

Gotta love those RASAs! Super image Olly. I looked at a widefield of my own. Not in the same league for signal-to-noise and colour.

For all you lovers of the aesthetics of deep sky images, I have posted some alternative processes of Rosette Nebula data in OSC in the Image Processing section. Please wander over and tell me what you think. I know it is all personal choice, but I am genuinely interested in what people are looking for in a deep sky image. old_eyes

I have been playing around with slightly different processes of an OSC image of the Rosette Nebula, and I am interested in your comments and preferences. Which processing do you think does most justice to the object? Combining data from a number of projects I accumulated 9 hours OSC data from Pier 5 @Roboscopes in Spain (Tak Epsilon 180, ASI 2400MC Pro, Paramount MX unguided). I passed the data through my usual Pixinsight process - WBPP, DynamicBackgroundExtraction, BlurExterminator, SpectrophotometricColorCalibration, EZ Denoise, Starnet2 separation of stars and nebula. The star mask I stretched with ArcsinhStretch. The nebula I processed in two ways. First MaskedStretch, then either using GeneralizedHyperbolicStretch, focusing on enhancing the contrast on the nebula structures, or CurvesTransformation, trying to keep more of the background nebulosity/dust visible. After the stretch a small amount of LocalHistogramEqualization to bring out some of the structures. Then recombining with the stars using PixelMath and the max(star_mask, starless) function Using the generalized hyperbolic stretch, I produced this: [A] Lots of punch, but I have lost some of the outer nebulosity. Using the curves transformation, which I have had more practice with, I get this: [B] A softer rendition with more of the outer nebulosity and dust visible, but not so much contrast in the main nebula structure. Well, could I combine the best of both? This image [C], uses the max function in PixelMath to choose the brighter of the two pixels from the original images - max([A], [B]). This keeps the background nebulosity and dust, but strengthens the contrast and colour in the main nebula. The final image uses PixelMath to average [A] and [B] = ([A] + [B])/2 Really interested in which one you prefer, and any comments on what is wrong with my basic Pixinsight process.

You are of course right about re-ionisation. The bit that I found fascinating was the explanation about why, from one perspective, neutral atoms appeared so quickly, and from another, so slowly. All buried in the subtleties of quantum mechanics.

The early universe was a hot dense(ish) cloud of protons, neutrons, electrons, photons, neutrinos and probably a bunch of other stuff. This soup is opaque. Light doesn’t get through it. Then suddenly (well relatively suddenly), after 380,000 years neutral atoms form and the universe becomes transparent. When asked why, I have always resorted to waving my arms and saying that before that time the universe was too hot, and that is why 380k years is the closest we can hope to get to the Big Bang with photon based astronomy. but I never really understood why 380k years. Along comes a Medium article that explains it all simply and clearly. Worth a read and a chance to marvel at the Goldilocks universe that supports us. Just the right physical parameters. https://medium.com/starts-with-a-bang/the-quantum-reason-why-neutral-atoms-first-formed-9b6eae87dfbc

This is a three-panel mosaic captured from Pier 5 @Roboscopes in Spain (Tak Epsilon 180, ASI 2400MC Pro, Paramount MX unguided). 2 hours capture per panel, processed in PixInsight. I think the blue stars are a bit too blue. It looks a bit artificial, but it did get nice colours for the yellow and red stars. Original image scaled about 50% and an annotated version. I hope you like it.

In case anyone missed it, here is a thread on a sudden and potentially horrible problem with a Mesu 200 MkII and it's happy resolution.

Yes very lucky indeed. I was already planning a road trip to Sint Oedenrode for repairs and wondering what sort of paperwork/carnet I would need for a temporary import for surgery! The rig does go below 0.5" RMS for the right target on the right night, but I am happy with 0.6". As you say - not a limitation.

UPDATE. So I think (deep breath) we are OK. Immediately after the fault started I contacted Lucas Mesu, and he was his usual helpful self. Checking over the mount, I realised that the RA servo (the RA axis was the problem) was sticking out much further than the DEC servo and seemed loose. Lucas asked for some pictures and video, and when I touched the RA servo to show the problem it fell out of the mount. Fortunately not completely, as the cables and the equatorial wedge stopped it coming right out. Worrying that it was not a good idea to have an open hole into the RA mechanism, I pushed it back into place. Lucas sent over some pictures and measurements to show exactly the depth the servo should be inserted, and the orientation to prevent strain on the encoder connections. The servo is held in place by a grub screw and this was loose. I put the servo back as instructed, tightened the grub screw to what felt like a similar torque to the DEC axis servo, and nervously tested the mount. It seemed OK in daylight, slewing to roughly where I expected a target to be in the sky and returning to the parked position (at least to the accuracy of a spirit-level). My remaining worry was that the servo being out of position might have damaged the drive shaft or the encoder connections. So a live test was needed. Last night I was able to test under relatively clear skies and I got about 6 hours run time in total. At first, the guiding curve was poor, but I realised I had been knocking the whole system about a bit, so I recalibrated in PHD2, which settled the guiding down enormously. Polar alignment also seems to be a bit off, so there may be more to gain from sorting that out. Slewing, centring, meridian-flips etc all worked fine. I imaged the Horsehead Nebula (as this is a project I am working on at the moment). This is a PHD2 log chart for part of the session: Not great guiding, but the Horsehead is low down in my skies and the seeing was not great. For comparison, here is the guide chart for the same target on 2nd January before the problems started. Very similar results. I get better guiding with higher targets under better sky conditions, so I can be hopeful that the mount will be as before. It is tribute to the solid construction of the Mesu 200 that it was possible to put the RA drive back together and have it work normally. That and my luck. I have not explored the whole sky yet, so it is possible that there is a problem lurking there, but that would mean I had damaged the RA axis disk. Hopefully that is the stronger part of the mechanism and would be OK. If you have a Mesu mount, it might be a good idea to check that the grub screws holding the servos into their collars are not coming loose. I think I will check mine every year, just to be on the safe side. Anyway, panic over. Now I just have to deal with the North Wales skies! old_eyes

LBN 777 the Baby Eagle Nebula (also the Vulture Head Nebula) - part of the Taurus molecular cloud. 52 x 300s subs on Pier 5 @Roboscopes in Spain (Tak Epsilon 180, ZWO 2400MC Pro, unguided Paramount MX). Processed Pixinsight and cropped. I think the blue cast lower left might be real reflection nebula, but I am not sure. It looks a bit like what you see around the Pleiades. Any experience or comments?

Hi Jonk, We have moved on a bit doing some basic diagnostics. I will update when I have a solution. Situation MAY be different, and there might be an explanation, but I prefer to wait until Lucas gives me some confirmation.

Thanks all. Lucas is on the case and has asked for video evidence. That's the next step. But any thoughts from a Mesu owner welcome.

Hi all Mesu users. Got a problem and looking for advice. I have had a Mesu 200 MkII for a couple of years. I bought it from Bernard at Modern Astronomy in December 2020. So far it has worked extremely well, but I have just developed a major problem. Last night I was using it in my automated observatory as usual, and parked it at the end of the session. Today, I set up another run and found that the RA axis was making some strange noises and seemed to be slipping. The scope would not goto the area of the sky selected. I released the servo motors and reset the scope to the park position. However, when I engaged the servo motors again the DEC axis moved OK, but the RA axis did not. Neither under computer control of with the handset. The LED on one axis of the Sitech servo controller was blinking and the other steady. The RA axis was floppy, as if the servo was not engaged. I switched all power off and turned the mount back on again. Both LEDs on the Sitech controller were on. The DEC axis responded normally to the hand control pad, but the RA axis would not move. I tried releasing and re-engaging the servo motor several times but with no effect. Listening carefully, I could hear the servo motor rotating when it was engaged or not engaged. I also noted that the RA axis servo motor seemed loose in its housing. The encoder end of the servo moves by about 3-4mm side to side with a light touch. There is no movement in the DEC axis servo. Has anyone seen anything like this before? Are there any adjustments I can make to make the RA axis servo engage with the RA axis disk? I have emailed Lucas Mesu to see what he thinks, but wondered if there was anything I could do myself. old_eyes

Thanks for the advice and comments everyone.

Thanks. I must confess that up to now I have tended to set it and leave it, and so far with few problems. Clearly I have to be more active.

That's the easiest thing to do, and as I have a couple of hours possible this evening I will try that. I think I was worried that if the dew-band was set too high it might contribute to convection current in the dew-shield. But that is probably far less likely than dew/frost! I don't have automatic dew-heater controllers, but I have been thinking about a Pegasus UPB for other reasons, so may check that out.

This is probably and idiot question with a very simple answer, but I am having trouble keeping my Esprit 120 objective clear of dew/frost. Last night was clear so I was imaging away happily, monitoring progress from inside the house, when suddenly the subs went bad on me as if the sky had suddenly clouded over. It wasn't that, but when I went to investigate I had what initially looked like dew on the objective, but turned out to be a fairly substantial layer of frost. This despite having the dew-band operating at its usual setting. The ambient temperature wasn't that low (-2C), but there was quite a lot of moisture in the air. I turned the dew-band up to maximum but it did not clear the frost in a reasonable time. My first thought was that the dew-band had failed, but I check this morning and it was working. I used a temperature probe to measure the temperature under the dew-band and it was 6 degrees higher than the edge of the lens cell on the scope. So I wonder whether the heat input from the dew-band is being transmitted effectively to the lens cell. There is quite a gap on the Esprit 120 between the inner surface of the dew shield and the body of the scope. Options are: Whack the dew-band up to maximum and keep my fingers crossed. Add a second dew-band. Extend the dew-shield with some foam camping mat. Change the position of the dew-band. At the moment it is wrapped around the dew-shield at the position of the lens cell. perhaps it would be better at the base of the dew-shield allowing better conduction to the body of the scope and thus the lens. Chalk it up to unfortunate weather conditions and live with it. It is the first time I have actually seen frost on the lens. I am using the Lynx Astro 4-port dew controller together with Lynx Astro dew bands on main scope and guidescope. Any advice from other Esprit 120 users, people who have fixed similar problems, or experts on dew prevention gratefully received. old_eyes