pipnina

I finally caught a gap in the clouds, but due to equipment malfunction and the brevity of the cloudless window, I only caught one un-polluted 120-second exposure with my new 3nm chroma Ha filter. I chose the region around Sadr because I have long wished to see it and was curious as to the level of detail it contained, as well as because I already knew it to be a bright object. I am not dsappointed and when the opportunity arises I intend to complete this with more data! Maybe even give it a go in SHO once my auto focuser arrives (these chroma filters are very parfocal within the LRGB set, but the narrowbands seem to shift a fair deal.) I also created a synthetic colour version All in all for 120 seconds with an f4r reflector under bortle 5/6 skies this is impressive beyond words. I got a test using my lum filter in as well at the same exposure time, and there was almost no nebula to see.

What is the total integration for each channel and luminance? IMO the benefit of adding luminance is that in one hour, you are capturing the equivalent of THREE hours of RGB in terms of signal to noise. This means getting clean brightness data is way faster and you can pick out faint things easier and darker structure will look cleaner. However there is a limit to this. And in my so far limited experience with a mono cam, I think adding luminance is not worth it until R G and B have at least 2 hours each (if you're going for galaxies). And at that point, luminance must have a MINIMUM of 2 hours to not *add* noise to that image. IMO you should go for luminance only if you're prepared to double your imaging time to add it and bring out clean faint objects and structure. Maybe the more experienced here would disagree. Both of these images look great however, and I'd agree with you that LRGB and RGB seem very similar indeed.

I've always wondered why the RAW image files from these telescopes can be so hard to find, since they are not privately owned or operated but paid for with international tax money. But I found a website (most likely intended for researchers) that lets you view the various obsrvations with a variety of supporting and pre or post-calibrated files. You need to filter searches somewhat to find the observation code, then make a request for the date relating to those codes, then access it via FTP client... But I got some hubble raws of the crab nebula. I now realise 2 things: The uncalibrated raws have HUGE artifacts. Bright stars bloom on spilling columns (I forget the name of the CCD effect), LOOOADS of cosmic ray strikes, and I think a nasty 45 degree angle square rounded filter silhouette!? They provided various calibrations as well as other files I am not sure of the purpose of, but they don't match the source image's paramaters! Plus a final calibrated image has distortion relative to the RAW and also JPEG artifacts... And somehow a single fits is opening multiple image tabs in GIMP. Example: RAW (stretched and curves) Calibrated Some kind of cosmic ray / bad column mask? No idea what these are! I think it's fascinating to see what this telescope captures before human hands touch it, but I also find it very confusing from a "why is the camera's FOV not used properly / vignetted", "why a single 45 minute exposure instead of 9x5 min or 5x 9 min to remove cosmic rays?" or "why does their CCD bloom so harshly". Not to mention "why is it so hard to find these files to begin with!" What do you guys think?

Ah I see! Many thanks

Hi! My chroma narrowband filters just arrived and they gave me two charts with each one. One chart is as seen on the shopping page (% transmission, in a range of 300 to 1100nm, so these 3nm filters are very hard to see the true useful bandpass) But they also came with a second graph of "optical density" which was not on the FLO website (I presume since each batch may be slightly different?). This graph's scan range is of only 646 to 666nm on the Ha filter, so the true bandpass is easy to see, assuming what i'm looking at is the same as the first graph, but inverted? It seems to show that my filter would pass 100% from 655.5 to 657.5, and only be slightly tapered at 658. This might be good since I was initially worried that even some closer/larger galaxies like M51, M82 and M66 would be down in the depths of the filter's downward curve after I did some redshift maths, but this might mean I have more sensitivity to the red end than I expected?

Looking at your images, I think 67P/Churyumov-Gerasimenko does have a bit of green to it, however I think the reason you're struggling is simply because your signal-to-noise is not high enough to distinguish parts of your image beyond the colour noise. You may be able to tease some more out with some of my favourite methods: Open your stacked and stretched tiff in rawtherapee: Then go to the colour tab (the second tab) In the colour tab you will find noise reduction as an option, turn it on but don't apply any luminance. Change Chrominance from automatic global to manual, then put the master slider all the way to the right. Then see if you can saturation-boost the comet to be green. This method SERIOUSLY smooths out the background RGB graininess into a flat colour. If you have enough SNR to create a green comet, then this will let you do it. I like to go back to the exposure tab at this point and edit the LAB colour curves to tease colour out in the most natural way I can. For example, CC lets you adjust the saturation of objects, based on their saturation before LAB is applied. This lets you boost saturation without causing clipping. CL is my favourite for astro, because it adjusts saturation based on brightness. You can use this to boost the saturation of brighter parts of your image (i.e. comet tail) while clipping out sautation in the background (so you can minimise RGB noise as well as background gradients while having a nice colour image) Hope these tips help. I don't know what processing software you use but I imagine lightroom also has similar features.

I think the biggest upgrade for the money would be replacing the black ring that has the two thumb screws, with one that has the brass compression ring design. It unscrews and I have seen someone else use that mod on their 130P-DS. I know my own 130P-DS seemed like it had focuser sag, when in reality the two metal pinchers just couldn't grip my coma corrector properly and it was flopping around no matter how tight I made them! I don't know if the tube itself can handle enough stress for the focuser to become the problem however... Just touching the guidescope in the shoe is enough to show us signs of the thin metal flexing. You also introduce the risk of causing light leaks and further deforming the tube by changing the whole focuser. This scope is a real cheapo so I don't know if it's worth spending the same money as the scope cost new to put a good focuser on it or not. Hopefully others come along with there experiences too!

Hi! I have plans to image things like the iris nebula and the integrated flux nebula near polaris, but I have noticed that despite my best attempts to polar align (using Ekos' polar alignment routine with my astrocam and getting things to a matter of seconds away from true) I still see field rotation across my images, such as a recent M81/82 daat set I collected and put through pixinsight's blink feature. I have made sure my guidecam is roughly aligned with the telescope (M81 and M82 were both in the FOV during the beforementioned session, so guide stars were in the same place as the imaging. Perhaps cone error or maybe untrue bearings are to blame in my HEQ5? Alternatively, my scope (now an 8" TS photon) does seem easy to wobble in the vixen style dovetail and puck, perhaps the scope is rotating in its seat due to flexture? I also noticed when I first got PHD working (only got guiding recently) that it failed to perform the calibration on RA, and in the end I realised I was pointed at polaris, and as such the small RA movements PHD was making would have almost no effect. Can PHD setting be tuned to work up there or am I out of luck for guiding up in that region? I also am curious about objects that are under the pole. Can they be reaonably imaged or are there restrictions with our EQ mounts when it comes to the observable area under the celestial pole? My mind goes a bit numb thinking about how the mount would need to position itself to do something like follow polaris around if it were below the pole vs above it, while keeping polaris in the center of the field and without rotation. Advice appreciated! Forecast is poor tonight but I see an absence of clouds so I shall chance it! Many thanks

My "reject high" map in pixinsight looks like a cobweb! Sometimes the trails are not all rejected however : ( There are usually one or two left over even in one of my stacks of 800 images!

For all forms of astronomy, being at 50+ degrees north and missing multiple months of astronomy time (unless planets are high at that time I suppose) every year. Plus, british weather being what it is! Not to mention the months where we have no darkness also happen to coincide with the longest spells of clear skies we will see all year! For photography... It has to be equipment malfunctions. Nothing worse than not being able to work out WHY something isn't right... But something DEFINITELY isn't right! At the moment I'm suffering there because of reflections, collimation shift (I really don't want to have to take the primary out and use sealant on it... May be the only choice)

if the star adventurer's 5kg is inclusive of the dovetail and counterweight that would make it different to all of the other skywatcher mounts. Certainly my HEQ5 has about an 11 to 15kg weight limit and I am at 11ish with only mt telescope, let alone the 10kg of counterweights on the other side! I haven't weighed my star adventurer setup, but I had the 1kg counterweight plus a heavy sigma 105 f2.8 lens and a battery extension on my swsa maybe two weeks ago and it seemed to cope just fine... as long as I had it balanced (I set it up incorrectly, and the balance was only good for some of the axis rotation, as the night went on my images became more and more elongated- oops! I think your current weight at just about 5kg is going to be ok as long as you are balancing it nicely.

My Leo triplet LRGB I made earlier with my new mono cooled cam had about 15 hours of L, in 1 min subs. I only barely got the tail of the hamburger and it was faint. Meanwhile with 4 min subs (once I got my guidecam) and using only RGB (about 120min total) I was starting to see little hints of IFN showing through around M81. I think longer subs help, but for me the benefit of reducing the burden on my computer storage is as good a reason as any to go as long as possible! That 20h total LRGB of the Leo Triplet created a project folder of about 500GB in size once pixinsight was done... 25% of my SSD's total capacity.

I have seen some people mention that filter can need to be fitted with one side facing the telescope and another facing the camera. I installed my chroma LRGB set in the way I pulled them out of the packet, not realising they may need to be in a certain way. Does anyone know if chromas are orientation-dependent, or can they be put in whichever side facing the camera? Cheers

I wonder what instrument commissioning entails : o This telescope literally made science with its first published image (of space), before the alignments were even remotely complete. Who knows what it's going to tell us in these next few weeks!

The focuser does flex slightly when I push on the laser, but if I turn the laser in a loose focuser it seems to stay put near enough.

I could swear I saw a post only recently talking about GSO/TS F4 newts, where the guys at FLO said spring issues were common but have been revised, and changing springs should no longer be necessary. 😕 Maybe it was true, maybe not. All i know is that at the moment I can't seem to keep it collimated as it slews around the sky

Yes it moves in and out of colimation in the same pattern as I turn the DEC and RA axis. So if I flip DEC 180 degrees, it moves out of collimation, then I move it back to the staring position and it's back to being collimated again.

Hello I upgraded from a 130P-DS to a TS-PHOTON 200 F4 very recently and while mostly the build quality is an improvement, I have noticed that even though the locking screws are quite tight, the scope still shifts collimation quite a bit when i move it around the sky on the mount. I have the baader laser colli in the focuser (relatively collimated itself, I rotated it in the focuser and saw only minimal movement, within the helping circle on the primary), and where the telescope might be almost perfectly collimated in one position, if I swing it around (notably DEC) it shifts somehow and the collimation becomes very dodgy indeed! About half way to the edge of the laser collimator's guide mesh. This is a heavy scope, is it possible that it's simply overwhelming my HEQ5 somehow (dunno how that'd affect collimation but...), or flexing under its own weight? I do have a finderscope in the finder shoe, but only for a lack of other ways to mount it currently as the skywatcher dovetail used an unusual imperial thread while the photon's dovetails and tube rings are presumably metric (certainly they don't fit together). Is it also possible that the locking screws are *too* tight on the primary adjustment? Secondary alignment doesn't seem to shift much (again stays within, although sometimes at the edge of, the center guide circle on the primary) Any ideas, is this collimation error deadly for my images? It'd be very sad if I had to collimate for the specific patch of sky I want to image every night : ( Any help appreciated! Thanks!

I did not know of this effect! I will definitely have to start doing my flats properly (before not after imaging session) from now on, because while I don't touch the focus position before imaging, the scope probably warms rather considerably if i let it sit in the sun in the daytime.

I haven't attempted any widefield images with my DSLR since modding it, but the other night provided a good opportunity to try it out on cygnus with my 105mm f2.8 The weather did not co-operate (no clouds, just poor visibility coming and going) and my star adventurer was not balanced properly (lessons for next time!) but things turned out nicely in the end. I had snapped a 4 panel mosaic in monochrome using my telescope a little earlier, and figured it would be fun to scale the DSLR image up and merge the telescope data into it. I found a layer blending mode in GIMP that would allow me to put the colour data in the DSLR in front of the telescope's image, while keeping all of the detail in the mosaic. Well chuffed. It's a biggie though. The mosaic represents about 2 hours total time on luminance, while the DSLR image represents about 2.5 hours of total time in the stack. Hope you've all enjoyed some clear skies of your own!

I also have the 2GB pi and use astroberry too. I have run out of ram once or twice, but I can still complete an imaging session as long as I do things a certain way. Have low resources mode turned on in kstars (this stops previews from rendering above like 25% resolution, but that saves a lot of memory). Also I find if you need to open and close things too much it can cause issues. I tend to run everything locally on the PI because it saves issues with connection loss and cuts down on image download times to my PC indoors. Not sure what you are doing differently to me. I use whatever solver is installed by default, but I only have the necessary fits files installed for solving.

Your example looks pretty much exactly like what my 130P-DS produces with the Baader MPCC 3. This was before I removed any mirror clips. I have decided to replace it for a TS GPU coma corrector in hopes it gives me a better image overall. (No idea if this works with the 130P-DS but I kinda broke mine by cutting the focuser tube too short so I am using this as a convenient excuse to upgrade to an 8" f4) I did try a variety of spacings with my baader using shims (I think i ended up with too much in theory) and it didn't change a great deal.

That's also a good point. I'll give that a check tomorrow too. With collimation checks, If i can ensure that my secondary is straight and my spider vanes are equal lengths, (and ofc, that it doesn't look like the picture attached), does that mean I should basically seek to adjust the spider vanes to shift the secondary further to one side of the tube and then re-collimate there?

I checked my cone error after hearing some people suggest it could be causing issues with my guiding/pointing or polar alignment. I followed the tutorial here: https://www.youtube.com/watch?v=WatdQlPp22Y So I got my setup roughly pointed at this church a mile or so away. And with the RA axis level (I used a spirit level as instructed) I centered the cross above their bell tower in the field of view using DEC and AZ. I then flipped the scope on RA axis and got it level again, and found the horizon again using the DEC axis. Only to find my FOV had moved some good distance away (probably about 5-6 degrees, maybe more?). I adjusted the cone error seen by raising the rear tube ring away from the dovetail. I eventually ran out of thread for adjustment however before I reached the half way mark I was supposed to target! The photo on the laptop is after I performed the second iteration of the instructions- I flipped RA back to the starting point and leveled it, centered it back on the cross using DEC and RA, and then flipped RA and centered it again using DEC only. There is still some cone error left, but it's in the same direction as it was before I did any corrections, and I'm out of thread! I checked my collimation. The spider veins are all within 2mm of the same length as best as I can read, and the secondary mirror looks about right as I can tell, and the primary is properly collimated to the secondary as per my cheshire eyepiece. I just don't know why my scope would be so far away from where it should be in terms of cone adjustment, that I run out of thread! Does anyone have any ideas as to what I should do to get the rest of the adjustment? Also please forgive the state of my scope, I went a bit bananas on the tape to keep stray light out (especially on the primary mirror cell)

Oh yeah I bet that scope is a MONSTER double splitter! At least when the atmosphere wants to behave