symmetal

Looking at your fits file there is almost no red signal present. I converted it to 16 bit tiff and loaded it into Photoshop and gave it a levels stretch. As the histogram shows, green is dominant as would be expected but the red is only showing very faintly in the brighter nebula area. If I do a rough background equalization you can see the red histogram content is negligible. You need to have much longer exposures to get a better red narrowband Ha signal. The filter's green and blue OIII bandpass width is about three times wider than the red Ha bandpass width so your red signal will be the weakest of the three. If possible, then 3 to 5 mins exposures will be better and plenty of them. I assume you're in a light polluted area so too long exposures may overexpose the green too much though. I'd still have thought you would have got more red than you have though, looking at sample results from 60s exposures with this filter Definately don't select 8 bit instead of 16 bit. It will make things far worse with heavy posterization of the stretched data. 🙂 You can increase the camera gain if you wish to reduce the exposure duration. I'll have to check what the electron/ADU gain settings are on the ASI385MC first. Alan

If your protection device is inserted between the power supply and your astro gear it will be fine. The 30A is the maximum the power supply can deliver if it's required to do so. If your astro gear only consumes say 5A maximum that is all the power supply will deliver to it. According to ohms law V = I * R, (voltage = current * resistance) it can be rearranged as I = V / R or R = V / I If your equipment draws a maximum of 5A from 12V then its load resistance is 12 / 5 or 2.4 ohms. If supplied with 13.8V the maximum current it can draw is then 13.8 / 2.4 = 5.75 amps so your protection device will be fine. It's worth fitting a 10A fuse in the +ve wire from the power supply anyway as extra protection in the event of getting an accidental short circuit in your cabling. 🙂 In reality your equipment will be using less than the 5A anyway most of the time, only likely peaking to around 3A or so when slewing in both axis at once. Alan

Glad it's confirmed it's just a power problem. 🙂 The 5A rating of your supply is fine, it's the drop in voltage at the mount when a higher current is drawn which is the issue. It's easy to lose 0.5V or so between the power supply and the mount when drawing a few amps, enough to drop below the minimum mount voltage. A 13.8V supply is recommended, as it will allow quite a bit of voltage drop before the mount fails. A fixed 13.8V supply is probably preferable than a variable voltage one, just to avoid the possibly of changing the voltage during use. If you don't think that'll be an issue then the variable supply is fine. A 5A rating or higher would allow you to power some accessories too. 13.8V supplies are used in the amateur radio field so if you have a shop selling ham radio or CB equipment they will have 13.8V power supplies. Alan

When doing the alignment it starts moving in Dec, and as soon as it tries to move in RA as well, (so more current drawn) it shuts down. Try slewing manually in both axis at the same time and it will shut down too I expect. A better rated supply will solve your problems. 🙂 AstroKeith has just said much the same thing. Alan

No it won't be a problem. I run all my imaging equipment from switch mode power supplies, and have never had any power issues. The small amount of residual switching frequency, (around 100kHz), possibly present on the DC output won't matter. The mount is controlled by digital signals, including the stepper motors, so should be immune from a few millivolts rapid variations in the supply voltage. Some switch mode supplies are designed better than others though to reduce this interference to negligible amounts. Many cameras, (which have sensitive analogue circuitry reading the sensor) run just from 5V USB and the USB supply from the PC will have far more interference on it than the switch mode supply will have. Any circuitry that requires a very stable supply should have the necessary filtering before the circuitry to achieve this. 🙂 Alan

It'll be fine. Just be sure you don't accidently knock the set voltage knob while in use. Also, as with any mains powered equipment, if it's outside ensure it's covered to protect it from any dew that may form and have it powered via an RCD for additional safety. Alan

That's most impressive for just one sub per panel. 🙂 I did write a reply shortly after you posted it, but looks like I forgot to click submit. 🤔 Alan

@mgutierrez When you stack say 100 images to obtain a final lower noise image, you improve the SNR for each pixel, by stacking the same pixel in each image to get an average value for that single pixel closer to the actual value, which it would be if there were no noise present. For a more accurate sky background value you don't need to stack multiple images, you can stack multiple sky background pixels from the same image, the 100 x 100 pixel block vlaiv mentions, and so again get an average value much closer to the actual sky background value. You've therefore also improved the sky background value SNR. Alan

Thanks for the likes. 🤗 Would anyone like to comment on whether it looks too overprocessed, or the colour saturation is too high. Some of the bright stars have some odd looking flaring but I think it's due to reflections off the nearby dust. The odd shape bright star to the bottom-right of vdB152 is a double star. The blue 'halo' surrounding it, is I believe primarily due to dust reflections. 🙂 Alan

That's a real faint fuzzy. 😁 Alan

Swapped over the camera to the 6200MM for some NB now there's no astro dark and the Moon's up and needed to rotate the camera to get the correct orientation, so loosened off the RASA front ring to allow the adapter plate to rotate. Found the adapter plate still wouldn't rotate and realised the whole central lens assembly was rotating instead rather than the ring loosening. Holding the lens assembly with two fingers the adapter plate ring came undone easily so it wasn't done up too tight. The corrector plate is supplied with two metal plates firmly clamping the corrector plate between them and the lens and front ring assembly are fixed to these plates. It seems they aren't firmly clamped together anymore so everyting is rotating with the corrector plate staying still. 😭 This is a new scope and not the one that was dropped so is still in warranty. It's Friday again so can't contact FLO until Monday. The corrector plate needs removing to tighten up the two plates so I'm not doing that without permission, and Celestron have said removing the plate yourself voids the warrenty so I'll have to wait. 😟 The scopes been in the Sun, covered by a towel, for the past few hours ready for this evening so maybe the metal pieces expanded more than the corrector plate glass causing the issue. Luckily I got quite a few sets of images the past few weeks so can amuse myself processing them in the meantime. I don't think I'm meant to own a RASA. 😐 Alan

A very colourful area, vdb 152 itself is also called the Wolf's Cave Nebula. I've left off the LDN and Barnhard labels from PI annotation as they are way off in location. B175 is the 'pillar' above vdb 152 At the top left is the remains of the planetary nebula Dengel-Hartl 5, discovered in 1979, while the large red circle segment at the bottom left is part of supernova remnant SNR 110.3+11.3. There are three apparent galaxies just inside the SNR ring which don't appear to have any designations. Most images of this area seem to be very colour saturated with not so much of the fainter background detail. Before star removal processing this lack of detail is perhaps not surprising. 3 hours 20 mins of 90sec exposures, RASA 11, ASI2600MC on EQ8-R. Procesed in PI and PS. There being little to no actual sky background it took a bit of experimenting with DBE and ABE to get something which didn't show noticeable gradients. Alan

Thanks for the information. I may be able to get one good enough to submit in the future. Alan

Congratulations Göran. 😊 Well deserved. How do the magazines find out about the images? Do they look through astrobin and the like and ask if they can feature it, or did you submit it for possible use. Alan

Yes, I agree Göran. I'd have thought the background leftover, after removing the stars wouldn't have much to work with in this case, but there's plenty of detail visible. How much is interpolated data would be interesting to see. Doing star removal on linear data, with its smaller stars, is a big advantage here. Alan

Thanks Olly. 😊 On the higher stretched one, the red patches do appear more like reflected starlight as you say, and not Ha. It was hard determining the overall background colour as virtually the whole image is composed of different coloured dust. There looks like more interesting structures off to the right too so a follow up mosaic image is worth investigating. I now really appreciate having the RASA, as you can complete an image with acceptable noise, in just two hours. In my skies with so few clear nights, that's a real benefit. I have loads of unfinished targets taken with the FLT98, which is effectively redundant now as it's the same fl as the RASA11. I could use it to generate a star layer for the brighter stars I suppose to reduce the diffraction artifacts from the RASA if I'm being pedantic. 😉 Just for comparison here's the image quickly stretched without using star removal beforehand. 😲 Alan

Here is is with a bit more stretching which reduces the effect of the nebula compared to the previous one, though it shows a few more red patches and more detailed dust. I've boosted the stars a bit more too, as in reality they dominate the image so should be more apparent. I've also redone the annotation to include the extra catalogues which I'd just noticed were available if you clicked the + button. 😁 The 'random' LDN placements is quite amusing. The actual dark areas aren't included. 😄 Which one do you prefer? Alan

You also don't need to check each sample to see whether there are any stars enclosed either, so can quickly plonk them where you want with a larger sample box size. 🙂 On my laptop the image looks a bit dark so I'll redo it with a bit more oomph. Alan

It was fairly low in the sky around 30 to 35 degrees altitude but thought it was worth a try while it's visible in astro darkness, but it has turned out better than I hoped. There are so many stars, the background is hard to determine, so I tried the method posted by @Fegato of doing star removal before DBE and putting them back right after. This worked very well and revealed far more dust than is visible in the normal image. For BlurXTerminator I this time disabled star sharpening which preserved the star colours better. StarXTerminator was used again before separate stretching. Processed in PI and PS. I kept the dust fairly muted as in reality it would be swamped by the stars and not visible, apart from the very dark patches. There is a large faint red patch above the cocoon so maybe some Ha there. 2 hours of 2 min subs. RASA 11 and ASI2600MC on EQ8-R. Alan

Glad it's working now. 🙂 I bought PI only a month ago and the PSFImage was included I believe, though you can download it and add it yourself from from the PI Forum here. It's useful to get the PSF parameter for BlurXTerminator, which seems to performs better than using the 'auto PSF' option. Alan

It looks like it can't find suitable stars to do a PSF analysis. I asume the stars aren't all overexposed, out of focus, or badly elongated in shape. You can try running the Script / Render / PSFImage utility and see if it can determine the stars PSF value. The script takes a while to run on large images. If it does succeed try using the Moffat PSF Function used in the script in place of the 'Auto' PSF Type in the Signal Evalution section of SPCC. Alan

Excellent images. Alan

On 4th May 2023, Japan's Himawari-9 geostationary weather satellite caught a little visitor passing through on its 0040 UTC set of images. It has 16 narrowband channels and here's the one in the red spectrum at 640nm. 😊 It's a 5500 x 5500 pixel image. Alan

Now you mention it the top blue nebula does appear to have three similar structures one behind the other. The leading edge of the 'dorsal fin' also seems to consist of four very similar structures too. The denser patch on the front edge is repeated to a lesser degree in the structures behind. 🤔 Alan

Thanks everyone for your kind comments. 🤗 I did initially do a partial stretch using Generalised Hyperbolic Stretch using Mode 'Colour' under 'Colour Options' which is similar to an arcsinh stretch where colour saturation is preserved, to where the stars were visible, and the background just visible, then ran StarXterminator and found around 20 stars were not being removed. I had brought the GHS Symmetry Point in a bit to reduce the degree of background stretch, and maybe that changed the star profiles a bit such that they weren't detected properly. I'll have to do another test to see if that was the case. @Fegato Thanks for the tips. I'll give them a tryout along with the video. I'm new to PI so plenty to learn. 😀 I expose to swamp the read noise by at least a factor of 5 and with the ASI2600MC, for me that is around 50 seconds with the RASA 11, and I chose 2 mins to reduce the number of subs, and also increase the exposure time vs download time. The lack of star colour is also possibly due to BlurXterminator reducing star colour, when sharpen stars is selected. I'm just processing a new version of the Ursa Minor Dwarf and there is plenty of star colour all over the image with 2 mins exposure when I used BXT with sharpen stars at 0.0 which helped I think. Alan