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In Bortle 9 skies you probably won't need to go even that long with your exposure. I think just a couple of seconds per exposure will be needed - this of course means almost any decent mount will do - as long as it can carry your scope / camera combination.

Hi and welcome to SGL. First of all, both stock barlow lens and 10mm eyepiece that come with that scope are not very good/sharp. Second thing is that such combination is probably providing you with too much magnification for your scope. In theory, you should be fine with x180 but in practice only very sharp optics can do than and air / atmosphere needs to be steady. There is a lot of things that you can do to improve your views of the planets like: 1. Place your telescope on the grass surface and not concrete / pavement. Let it acclimatize to ambient temperature - leave it sitting for about hour or so. 2. Make sure you are not viewing over any houses or roads in summer. Concrete buildings and pavement absorb heat during the day and create thermals over night. It is like looking things over camp fire - everything shakes and image is blurry. 3. Be patient when observing planets - try to find best focus and wait for moment of good seeing when things become better. 4. Try to view with only 10mm and no barlow - less optical glass of dubious quality and less magnification. Things will be smaller but sharper and will have more contrast. With more experience you will learn to distinguish between good and poor atmospheric conditions and you will know when is good time to observe planets.

Two things come to mind here: 1. thermals - did C5 get a chance to cool properly on both nights and was second night thermally unstable (like getting cold quickly so scope could not keep up)? In any case this can cause issues for Cat vs refractor on second night 2. Type of seeing effects / aperture size. Effects of seeing change with aperture size. There is something called coherence length and coherence time. This is related to seeing cell size and especially to relationship between cell size and telescope aperture. Small apertures usually "fit" inside seeing cells most of the time and as result main seeing aberration is tilt - image shimmers rather than blurs. Larger apertures usually don't fit inside single seeing cell and this changes dominant aberration - it is no longer tilt and image starts to blur rather than only shimmer. Blurring is responsible for detail loss much more than shimmer. For this reason it is said that smaller apertures better tolerate poor seeing.

Two things come to mind: Vertical line is usually associated with Amici prism either 45 or 90 degrees. What sort of prism do you have in that scope? Can you view image in daylight - like spotting scope and is that image properly oriented? If so - prism could be par of a problem here as such prisms are usually low in quality (astronomical grade Amici prisms cost a lot of money). Second - it seems that focuser mechanism is not good / mirror is slipping. In no way there should be sudden change in focus - it should be gradual with normal working focuser. This could also mean that mirror is not fixed properly and that it also changes position - which would cause changes in collimation depending on where you point the scope.

Oh, I did not notice that - would have thought they have it in stock, but probably issues with supply at the moment.

My approach is to remove background and then stitch images while data is still linear. Once you have stitched larger versions - then proceed as usual.

I would rather go for 38mm version as it provides about the largest FOV one can get from 2" eyepiece. Here is comparison: I have ES82 6.7mm and 11mm. Both are excellent eyepieces and only drawback is that eye relief is tighter than stated - or rather feels tighter. 82 degrees eyepiece really requires one to get close to be able to see it all to the field stop so eye lens of eyepiece is recessed slightly and that makes it feel like tighter eye relief eyepiece. In any case, to me 11mm feels just a bit sharper than 6.7mm, but that could easily be down to seeing and optics used. When I compare 6.7mm to 6mm BCO on any given night - they render same level of detail and sharpness to my eye (well difference being magnification and FOV only really). I'm planning on adding 8.8mm so I guess that 14mm version can't be bad either (however I'm not 100% sure on that - I have not tried it). From a quick search on people's opinions on this EP - most consider it very sharp and often say it's their most used EP - I guess than it has to be as good as others in the line.

Since you expressed interest in 82 degrees FOV, how about ES82 11mm I can't speak highly enough about my sample - probably the sharpest eyepiece I ever used. Looking at your EP collection - I think you are missing ultra wide field one? Not in terms of apparent field thru the eyepiece, but rather maximum possible field of view for ED100 telescope - something that you can use now in summer to sweep milky way and observe large objects like M31 for example? Given your budget and what I said above, I guess this would be my recommendation: https://www.firstlightoptics.com/explore-scientific-eyepieces/explore-scientific-82-degree-series-eyepieces.html 11mm version for £129 + https://www.firstlightoptics.com/ovl-eyepieces/panaview-2-eyepieces.html 38mm version at £86 bringing total to slightly over budget £215 + delivery.

I could not play that video but I have strong suspicion I know what is going on. Something like this: (if you can't see the animation above - open this link in new tab: http://serve.trimacka.net/astro/Forum/2015-11-21/post_01/RA_vs_DEC.gif ) Linear drift is related to polar alignment - better polar alignment - slower drift. Zig/Zag movement is related to something called Periodic Error of the mount. Drive train of the mount is not perfect and circular components are not quite circles (but rather egg shaped - on a small scale). That is due to manufacturing tolerances and all - you simply can't make perfect circle. Two way to deal with periodic error (PE) - first is periodic error correction (PEC) and second of course is guiding. PEC can fix things to varying degree - sometimes providing larger benefits and sometimes only minor - depends on what the error is like. If it is "in sync", or rather all oscillatory errors are harmonics of main worm period - PEC can go a long way. On the other hand if PE consists of unrelated frequencies so baseline frequency is not related to worm period - there could be almost no improvement at all. In reality it is somewhere between the two and more often closer to first case - after all gears are made to power worm and it is likely that their period will be harmonic of worm period - so PEC is something worth doing. From what I can see, this mount has PEC capability so consult your manual on how to enable it and do the training. Guiding is self explanatory - and I would advise you to look into it. Maybe off axis guider would be good match for that scope.

It tells you mostly that your OTA is not parallel with your RA axis. This can happen regardless of polar alignment and most notably it is called cone error. You seem to have a bit of that (scope is pointing upwards / downwards of where it is supposed to point when in home position). Again not related to polar alignment - that is related to orientation of your camera. Rotate camera in focuser and you will change direction of star motion when you slew in RA or in DEC direction.

That is kind of obvious - Lunar observing is always fun with a small scope, but is lunar imaging as well? I finally managed to process capture of the other night - took some Jupiter, Saturn and this Moon image. Processing of this image took most of the day today. Mak 102mm, ASI178mcc at prime focus, AZGti mount. Took 9 panels, 1000 subs each at 3ms exposure. Full FOV / no ROI. 256 of each calibration frames - darks, flats and flat darks. Stacked best 90% of each in AS!3. Stitching in MS ICE, wavelets in Registax 6 and final touch up in Gimp 2.10. This is monochromatic image of green channel. Image has been reduced x2 in size - it was too much resolution I think for given number of subs and seeing at that time in that direction. Click on the image for full resolution image (right click / new tab sort of thing).

Indeed. One of my goals when getting this scope is to actually see how good "all-rounder" type scope this is. I intend to submit it to: - planetary/lunar visual - so far excellent - imaging planetary / lunar - this part shows planetary performance and I think it passes with flying colors here as well - lunar is being processed as we speak (again, a bit of surprise there as well, or maybe not surprising after seeing this) - EEVA / imaging platform - this will be demanding and of course DSO visual - probably weakest point since it is lacking widest views.

Here we have another one - tiny little Saturn , but looks very nice also: Same equipment, same conditions, 20ms subs this time and yes, same processing workflow (but darks applied this time - not sure if it makes any difference or not).

Thanks! I'm actually not quite satisfied with colour balance - it was just a simple - hit "auto white balance" in Registax and it did pretty good job versus data from camera, but I've got my own idea of how to get "true" color. Unfortunately, I have not yet found a way to do it in existing software and need to do some measurements first - with a colour chart and such (do color conversion to linear sRGB then apply gamma and so on ...). Thank you. No idea if it will make any difference. I usually like to remove the bias (as darks are really only bias at those speeds) and correct for pixel response non uniformity with flats (apparently CMOS sensors get some of that), but here SNR is so good and planet wobbled so much on sensor that it is properly dithered - I'm inclined to believe that there will be absolutely no difference Thanks. Conditions were rather good, here are short animated gif of ten consecutive subs (randomly taken from original recording) and result of stack prior to processing: It is quite still - or rather there is no much blurring only shimmering - I guess small aperture played a part there as it cuts thru smaller piece of atmosphere - less than size of seeing cell.

Well, it's only Jupiter for now since that is all I managed to process tonight. I also took a recording of Saturn and Moon as well - will process and post results tommorow. This was taken with 4" Maksutov (SW Mak102) on AZGti mount and ASI178mcc camera. No barlow was used - at native F/13. Stacked in AS!3 and wavelets in Registax 6. Final touch up in Gimp 2.10 Above is just "preliminary" processing since I did not use either darks nor flats, but I did take them. I'll do another round of stacking to see if there is any difference (although SNR is very good as is). 5 minute recording at ~126fps (6ms subs) for total of ~38000 subs taken, stacked best 80% (seeing was rather good and I could not tell the difference in top quality sub vs one at 20% from the end - most of seeing was in form of shimmer rather than blurring). Surprised to see that much planetary detail with only 4" scope.

I second addition of something in 17-21mm FL - you want around 2.5 - 3 mm exit pupil for deep sky ...

No reason not to go for it then. If you ever find yourself having issues because of too big pixels - you can always switch to OAG.

Yes, you are right, my mistake. That is not quite what I wanted to say. I was talking about best performance of the mount rather than ability to guide at all, but you are right, I should have been more specific and clear about that. Indeed - barlow will provide additional focal length and additional resolution. That will make centroid algorithm more precise. It is not about pixel size, nor focal length alone - combination of the two is important. Ah, ok, sorry about that. I'll try to be more straight forward with my explanations. It is about how precise something can be measured. Imagine you are trying to park a car in a garage where door is 3.2m wide, but I give you directions in whole meters - so I say either stay on course or shift left/right but one whole meter each time. Odds are - you will miss the garage door and hit the wall. Mount can be directed quite precisely in the sky but you don't tell it in precise units how much to move - using large pixels gives large "units" of move left/right (it depends on focal length). If you want mount to move precisely where its supposed to be - you need to tell it to move in small enough units. All the math above just calculates how small units you need depending on how fine your mount is. You can still use larger "units" in your directions but, and mount will respond but it simply won't be as precise as it can be - due to "coarse directions" rather than anything else. All of that is related to sharpness of your image. If mount moves a lot causing larger RMS guide error - that adds to blur and image becomes less sharp. It is one of contributing factors of overall resolution achieved - other two being aperture size and seeing. It is therefore straight forward to see that you want as low (true) guide RMS as possible. As pointed above, ASI120mm will do excellent job - both in pixel size and in general. It will also be cheaper than Lodestar X2. Do you have any particular reason to prefer Lodestar + Barlow option?

Did image look soft while observing at eyepiece of just with camera? What were observing conditions like for you - what did you observe that looked blurry / soft?

No, I'm not saying any of that and honestly, I'm failing to see what in my post lead you to that conclusion. First - I'm not saying that Lodestar X2 has too large pixels to guide HEQ5/EQ6 class mount. That depends on focal length used - not on aperture size. I'm also not saying that one can't use Lodestar X2 with certain focal length to guide HEQ5/EQ6 class mount even if guide resolution is too coarse - you can certainly guide your mount, only question is how well? In first post you asked what would be a good guide camera. I understood term good in a certain way - for me good guide camera will one that will enable mount to perform to its best (given choice of guide scope). I've shown that you can't reliably guide below about 1" RMS with Lodestar X2 and 60mm F/5.9 scope simply because it lacks precision to measure star position accurately. If you want to use Lodestar to guide to better precision - you certainly can - just change focal length of guide scope so that it has better precision. Alternatively, if you don't want to change guide scope - then select guide camera that has smaller pixels - sufficiently small to enable good centroid precision for your mount. Btw, I would expect EQ8 class mount to guide to at least 0.5" RMS or less and above calculation and recommendation is valid.

I'm not seeing it. Maybe easiest way to see if it is concentric is to make mirror - either horizontal or vertical of half of the image. If it still appears circular - it is concentric. Here is first image with right part mirrored on left side: and here is bottom part mirrored on the top: That looks concentric to me. In fact, maybe this can show it even better: Inner circle is a bit misshapen (seeing, tube currents?) but it is concentric.

That is way too defocused for proper star test. Last image shows out of collimation optics, but I suspect that is because focuser was racked all the way out and that could tilt the primary mirror. You want very small level of defocus, something like this: You want those concentric rings to still be visible. Btw - one on the right is out of collimation because rings are not concentric - that is what you want to see - either concentric rings or slightly closer on one side. In your images above - first two images look rather concentric, but it is hard to tell because there are so many rings that they appear like flat surface. Last one is obviously not concentric.

But then again - you are not actually guiding either 55mm lens nor 1000mm F/5 reflector - you are guiding the mount holding either of those

Sampling rate of main camera and sampling rate of guide camera are only related by bunch of rules of thumb but in principle are not related. We could say that there is two schools of thought at work here. 1. Good enough 2. Best given circumstances Using first school of thought you can get to relationship between guide resolution and imaging resolution and it goes something like this: - under reasonable circumstances you need your guide RMS to be at least half of your imaging resolution. You probably heard about this rule of the thumb - There is 1/16 centroid accuracy thing and x3 of that accuracy per guide RMS which generally give about x5 guiding resolution vs guide RMS. Put those two together and you get our general rule of thumb that says something - make your guide resolution about x2.5 that of imaging resolution. This approach is "good enough" kind of approach, and using this approach you are fine with Lodestar as it gives you x1.33 ratio to your imaging resolution. Let's now try a bit different approach - approach number two that will try to do the best given circumstances. Rationale behind this approach is simple - if you can, why not go for best result given your circumstances? To explain it a bit better - your imaging resolution is 3.55"/px. Does this mean that you should settle for 1.77" RMS guide error just because rule of thumb says that it should be (at least) half of imaging resolution? Notice that - at least part in parenthesis. If your mount is capable of doing 0.8" RMS guide precision - why not go with that. If you compare two images - both sampled at 3.55"/px and one being guided at 0.8" RMS and other at 1.7" RMS you will see the difference in sharpness between the two - regardless of the fact that you are sampling at rather low rate. Why not aim for the sharpest possible image given your setup? In this approach - we don't look at guide resolution in relation to imaging resolution, we look at guide resolution with respect to what your mount can achieve at its best. This is your starting point. What mount do you have and what sort of guide performance does such mount usually have? I gave you an example for mount capable of 0.5" RMS. But we don't have to do it like that - we can do reverse. Given your guide scope at 355mm and lodestar with 8.2um pixel size - what would be the best mount performance this combo is capable of guiding. This works out to 4.76"/px, so if we take 1/16 of that, that is about 0.3". Multiply that with at least x3 to get resulting RMS - and that is 0.9" RMS. So that setup is only good for mounts that on average do above 1" RMS and only in exceptional circumstances can achieve 0.9" RMS. HEQ5/EQ6/AZEQ6 and all of those mounts are capable of better guide performance. Why limit them with guide setup that can't measure star position with enough accuracy to be able to instruct the mount to track better? ASI290 has 2.9um pixel size, while X2 lodestar has 8.2um pixel size. One is too large and does not provide enough resolution to be able guide mount like HEQ5/EQ6, while other has too much resolution with said guide scope - you don't need that much precision and smaller pixel size is less sensitive (part of guide performance comes from good SNR on guide star so you want that as well). You can't split pixels on Lodestar, but you can bin pixels on ASI290 to get to pixel size that both balances sensitivity and resolution needed to determine star position to a good precision needed to properly guide mount like HEQ5/EQ6. If you on the other hand have mount like Mesu200 or similar that can guide below 0.3" RMS - then I would say - use ASI290 but don't bin it - as you'll need that much precision in order to guide mount with such low error.

Let's try it this way: - re sampling resolution - depends on what scope you are using, quality of your mount and how wide you want to go. 1"/px is very high resolution and in most cases unattainable. You need mount that guides at least at 0.5" RMS or lower. You need very steady skies and you need at least 8" of aperture to get there. For telescope of 80-100mm of aperture, realistic maximum sampling rate is at about 2"/px. This does not mean that you have to go that high - if looking for wide field setup - simple fact is that you have limited size of sensor / corrected field and you won't be able to fit that many pixels. 3.5"/px is fine sampling rate for wide field. If we want to be specific about max sampling rate and Nyquist - there is simple rule to follow - measure your FWHM and go with sampling rate that is about 1.6 less than that. This means that one needs 1.6" FWHM stars in order to fully exploit 1"/px sampling rate. - re guiding resolution. Well depends on the mount you have and what is realistically achievable in terms of guide RMS. My advice would be to sample at about x3 per best possible RMS in terms of centroid accuracy. Centroid accuracy is about 1/16 - 1/20 of single pixel. To give a bit better explanation, here is how to calculate guider resolution. Let's say that you have mount that is capable of 0.5" RMS guiding under best circumstances. You want your centroid accuracy to be about 0.5/3 = 0.167". That will be 1/16 to 1/20 of a pixel so pixel size needs to be 0.167 * 16 to 0.167 * 20 = 2.67"/px to 3.34"/px You have guide scope that is 60mm F/5.9 or about 350mm of FL. You need a camera that has less than 6um pixel size to use as a guiding camera. With most common pixel size of 3.75um and 350mm of FL, you'll get 2.21"/px - which is slightly better than you need. With 290mm camera, which is a good choice for guide camera, you'll have 1.71"/px and if you choose that camera, then use x2 bin to further improve it's sensitivity as it will still provide you with 3.42"/px - close enough for above criteria. Hope this helps?