Adreneline

I've been trying to get guiding working with my ASIair + CEM25-EC + EvoGuide with 120MM-mini - it's proving difficult. Whatever last night I managed to get 10 x 120s guided and dithered and 10 x 120s unguided (no dithering) of M101 - the target was not relevant. The result was not what I expected. The guided and dithered clearly has a lower background noise level but what's with the hot pixels?! Hot pixels are not present in the unguided version at all - and there was me thinking dithering was one way to get rid of hot pixels. I've done my best to pre and post process both images exactly the same in PI. Am I doing something wrong? Any help or insights would be appreciated. Thanks. Adrian

Best to check the centres would still be aligned when mounted on a bar - I fear they may not Good luck with the Samyang - it's a great lens. Adrian

Or both! If you get one you'll wish you had the other I look forward to seeing the results of the modded 6D. Good luck. Adrian

Hi Jody! You'll be pleased to know I can't see a trace of magenta on my monitor. I loaded your image into Affinity and sampled the background to examine the RGB levels. As you can see from the four sample points the RGB levels are all pretty similar (a good thing) and most importantly the Red and Blue are not significantly higher values than the Green. One thing I was advised to do was to try not to clip the black point and it was a good idea to try to get the background to be around the R:G:B = 23:23:23 or thereabouts. You can see from the image above that the histogram is pretty much up against the left hand axis; it's a good idea to have a bit of space to the left of the histogram. The advantage of not clipping the black point is that quit often you find feint nebulosity is revealed. I know many though prefer the 'blackness of space" look and the subject of the image appearing to hang in the darkness. It's a totally personal preference thing I think - whatever works for you - but I pass on the advice so you can decide. It's a great image - one to be proud of! HTH Adrian P.S. I have to say I tend to go for around the 18:18:18 mark as per my attached image of M51 taken some time ago - and processed some time ago! M51+aa.tiff

I use an EAF and have always positioned directly above the lens, mounted off the WO tube ring/support. I've mounted "to the side" in the past but it makes balancing such a pain. I'm thinking of mounting the EAF under the lens but that means creating stand-offs for the tube rings and would probably impact on the stability. To be fair I could just manage with manual focus for now. I don't really want to guide but I would like to dither. Adrian

Been playing around with alternative mounting of my Samyang 135mm with my ASI294MC using Primaluce Lab tube 80mm rings. It's solved the problem I was having mounting a guide scope and compared with the previous WO clamp it allows me to change the aperture but I now have to decide how to mount my focusser. Um? Any suggestions? 🤞 Hope this is of interest to someone. Adrian

Not that is any consolation or help but I have experienced the same difficulties with the mini guide scope. I added a 1.25" nose piece extensions to the camera which allowed me to increase the back focus, however, even with a mechanically "secure" camera I still really struggle to achieve a good level of focus compared with my SW Evo Guide. The FWHM with the mini guide scope is consistently above 4 compared with the Evo Guide which typically achieves better than 3. It is worth noting that I need to use the same nose piece extension when using the camera with the Evo Guide. Fitting a spare 1.25" UV/IR filter to the camera seemed to help as well. Adrian

I've recently bought the 294 to use with my RedCat and my Samyang 135 fully aware of the fact that the images will be undersampled. That said I've been more than happy with the results recognising the RedCat + 294 is a widefield imaging setup and I for one don't go in for pixel peeping on widefield images. I also have a 6" RC with a .7 f/r which is a very good match for the 294 and although to date I have done very little with this pairing it has given encouraging results which will stand up to a fair degree of pixel peeping. You never know what you might buy in the future but it might not be unreasonable to assume it will have a longer focal length than the RedCat. HTH Adrian

Very good star colours.

It's Bortle 3 round here so not too bad really. I took a lot more lights but very high cloud put paid to quite a few. It is just RGB albeit with a UV/IR filter on the front of the camera. It's always difficult knowing when to stop with the processing. I was trying to maximise the contrast whilst at the same time keeping the stars under control. A tricky business! Thanks for the kind comments. Adrian

Thank you Martin - the Samyang is good for "hoovering up" photons. The trick is knowing what to do with 'em once you've got 'em in the bag! Thanks again. Adrian

Really good photograph. I love the balance of grassy foreground and sky with the magical Northern Lights and the Milky Way and the lights from the small town in the middle distance. Brilliant composition. Adrian

Thanks Adam. I collected the data on the 20th/21st and the above is my 5th or 6th revision. Time to stop I think. Adrian

I know I've not got near enough data but this is my first attempt at processing IFN in the region of M81/M82. I've tried every trick I know to stretch the data, contain the stars and minimise the noise - all with varying degrees of success - or failure! Anyway I thought I'd share and hopefully get some helpful C&C. Taken with an ASI294MC + Samyang 135mm - 51 x 120s. Adrian

Yes I am sure I have the spacing correct. The focus position is within the foot of the 'L' mark. I am using the lens at f2 so I am not surprised star shapes in the corners are less than perfect. To be honest the fov with this camera is such that I tend to crop off the edges anyway. In my opinion, being contenscious, the Samyang 135mm is not a lens suited to pixel peepers - it is more suited to imagers who want a large field of view without necessarily having to get into mosaics. I like the fact I can image all of IC1396 for example and the surrounding space and enjoy the majesty of the whole thing. I am not interested in looking at detail at the stars in the corners. Let's not lose sight of the fact that this is not an astronomical telescope, it is a consumer photography lens, and a budget manual one at that. Sounds like you have a good one and maybe I don't.

I've just started using a ASI294MC-Pro with my Samyang 135mm and so far I've been pleased with the results. That said I've been using it to try to image IFN where I am not so bothered about the undersampling - pixel peeping at the stars can be disappointing. I also wanted to be able to capture RGB stars etc. to combine with my RedCat NB imaging rig using a ASI1600MM-Pro. I also bought the 294 because I also own a StellaLyra 6" RC (f9) and the larger pixel size and sensitivity is a good match. You never know what you might buy in the future! Adrian P.S. This is my latest attempt at IFN - it is nothing to write home about or show on the Imaging forum but it will allow you to see how the stars look. The image is 51 x 120s exposures, gain 120, default offset, temp -20 degrees. There is only minimal edge cropping and my flats needs som work (I think). Two hours barely starts to show the IFN - I think another 20 might be required! There is no guiding on this image - I'm relying on the CEM25-EC to perform well with a light very well balanced payload. HTH

Well I don't know! What I do know is that when I had a WO scope (Z71) the equivalent diagram for that scope worked for me using a WO R/F.

Hi. Have you seen this?: This gives the spacing from the end of the flattener to the sensor as 54.80. The ASI294MC sensor is set 6.5mm inside the camera so you need 54.8-6.5=48.3mm of spacers. You just need appropriate M42 spacers to make up the gap. Adrian

Thank you. I am literally at ground zero knowing what to do with processing and setting up. I've still got to learn about Live View using my ASI294MC; I was using it with an ASIair which is not ideal. I wondered about using the BM but it seemed better than trying to judge it based on what I could see on the iPad screen of the terminator region. I was also manually focussing as I don't have a motorised unit fitted on the RC as yet. I am aware of what Topaz can introduce if used with abandon. I normally use the low light setting and have no sharpening at all, just very minimal noise reduction. On this image I used a sharpen setting of 1 - I couldn't pick anything less. Thanks for your hlep and advice. Adrian

I've been imaging DSO and the likes for the last four plus years but last night I pointed by StellaLyra 6" RC equipped with ZWO ASI294MC and a Baader UV/IR cut filter at the Moon having first focussed up on a nearby star using a BM. This is the result of 100 x 0.01s images stacked in Affinity. I clearly have a lot to learn but I was quite pleased with this first attempt. The lights were not calibrated in any way. I suppose I should have least used flats but I can't see any signs of dust motes and the vignetting was outside the Moon fov. At only 0.01s exposure I assumed darks were also superfluous or at the very least would offer little benefit. Affinity made short work of debayering and stacking the lights and the resulting 16 bit tiff was taken into PI to balance colours followed by sharpening and denoising in Topaz DeNoise AI (settings of 1 for denoise and 1 for sharpen - so pretty minimal). The transition region from the Moon surface to 'space" leaves something to be desired so don't go mad pixel peeping Thanks for looking and any tips or advice would be much appreciated as I really don't have a clue! Adrian

Have to say I would have thought the darks would have removed the hot pixels. Can you see the hot pixels on the stretched darks? I would have thought dark frame subtraction in DSS should remove them? (I wrote my reply at about 1.00 a.m. and I was blowed if I could bring the term "hot pixel" to mind - thanks to Peter @PeterCPC for reminding me). Dark frame subtraction should also remove any amp glow. Looking at your image the corner glows may be light pollution. Have you tried some sort of gradient removal in GIMP? Looking at your stars it looks as though you are not guiding as there is slight evidence of star trails/elongation- no guiding implies that dithering is not an option. HTH Adrian

Hi. The image you uploaded is showing as "Unavailable". It might be better if you upload a jpg so we can see the image without needing to download it first. I used to have a 414ex osc and it would exhibit similar "light corners" if it was not cooled enough; I seem to recall cooling to -15 degrees. As for the red, green and blue dots - not sure. What software are you using to pre-process, i.e. calibrate and integrate/stack? Did you take bias, darks and flats? The thought occurs they are 'blown pixels' (full On) and so will show as red, green or blue dots. Darks would remove these during pre-processing. Adrian

Inspiring! That gives a whole new meaning to commitment and dedication.

I grew up close to RAF Gaydon which was a V bomber base. At the annual airshow there would be a V Bomber Scramble when four Vulcans or four Viktors would do a mock scramble take-off. That was a seriously impressive sight and sound. Once airborne four Valiants would be hot on their tail. It was around 1960 so at the height of the Cold War. I used to go armed with my Observer Book of Aircraft, which sadly I don't think I have anymore

I agree! - I think As Lee says whatever you add/subtract it needs to be in very small amounts. I am sure it does pay off to get it "bang on" as star shapes into the corners are much better. Adrian