ONIKKINEN

I am seeing some weird weather phenomena that i cant quite explain, maybe the hivemind at SGL can help with this one? There is this bright white round blob rising in the east at the moment that i have not seen in ages, very odd, i wonder what that is. Skies are also more or less black instead of gray or white, with the occasional tiny speckle of light pushing through the void 😲.

I believe the flat wizard uses whatever you have set the default offset to be. If you have set it to 700, all should be good but if you have left default offset at 768 and just use 700 for imaging sequences, your flats will be at higher offset.

Did you use darkflats and darks with calibration? Without those you will have overcorrection of flats and they look like yours. Alternatively if you have some weird offset issues where some of the calibration frames are taken at different offsets to the lights you will get this kind of deal, or maybe a little bit of overcorrection if the offset were 0. As for the NINA flats issue, no clue but i actually also ran into this issue. Previously i shot with a Maxfield 0.95x coma corrector and flats exposures were 0.136s give or take a few decimals in the end when using NINA flats wizard, but now i have a TeleVue Paracorr which is a 1.15x barlow, so flats exposures are increased to 0.205s. Thing is, NINA flats wizard refuses to figure out the exposure 3/4 of the time and says something about the panel being too bright and no solution was found to get a good exposure(cant recall exactly what). But manually taking the flats works just fine. Below is what a histogram looks like where flats calibration works with no apparent flaws: My panel is a plastic toy - quality amazon tracing LED panel and visually a little bit bluer than neutral white, hence the blues and reds switched places to what you would expect based on the QE curve of the camera. This flat calibrates all the channels just fine so have not bothered looking into a proper panel. If you want to, you could post one of each calibration frame and a matching light frame preferably straight off the camera in .FITS format and others could have a look. Its easy to overlook something and get left with odd looking data.

Dithering is a random motion that is done between frames, which will make hot pixels like these ones disappear with rejection stacking. Yours are very pronounced because of no dithering and so they appear as a line (because of polar alignment error induced drift and or other sources of misaligbment). If you are guiding you can set the guider to do this automatically between frames, if not youll have to do it yourself. Some software also allow a "direct dither" without guiding. Others have suggested darks, which will also remove hot pixels but this is not a substitute for dithers. Darks also should not be used with canon cameras as they do internal calibration of their own that results in 2048 median pixel value regardless of dark exposure length or sensor temperature (so the darks are pointless and only add noise). So in short, darks remove hot pixels, but you will still need to dither to remove walking pattern noise completely. Dithering does both, so dithering is the ultimate fix.

Did you guide or dither? This is walking noise, and dithering is the cure. Guiding alleviates it somewhat but dithering is the real fix. You can dither without guiding too, just move both of the axis a good 20+ pixels every few shots. Ideally once per 5min, but every dither helps in the end if you cant be bothered to do that every 5 minutes.

As feedback i think your image looks pretty good for such a short integration, but colour calibration could take another look for this one. Try the photometric colour calibration tool in Siril, and maybe SCNR green if necessary (not always the case). Could just be a little bit too much saturation if you did do PCC. Dust can move between your lights and flats, so its possible it just wasnt removable this time. Did you take flats directly at the end of the session without removing the camera from the scope? If you moved the kit inbetween your lights and flats you will also get bad calibration.

This is what the manual says too. Always finish with a rising adjustment and there is no slop.

I am using an old version of NINA so it may have changed but have you tried clicking on the number itself? Click on the number and it allows you to type the number instead of pushing the + button 120 times.

Fair is a matter of perspective, i for once have not seen an arc second of clear sky since late october and will not be seeing this event. Or the opposition from how it looks like. Lucky if i get another night in 2022!

Great travel setup, except for the mount. With an 8" newtonian you will want to have an EQ6 ir at minimum an HEQ5 to run it satisfactorily. My mobile setup is an 8" newtonian, AZ-EQ6 and all the related accessories and kit. I used to have a lighter mount, an EQM35 and it was just as much trouble to haul as the twice as heavy AZ-EQ6. If you want a true backpacker setup you are looking at a tiny startracker and a lens/camera combo which is obviously limited to certain targets only because of the size. If you want bigger than that because you want to make the most of your infrequent use of the kit you might as well haul the biggest scope out. Doesnt matter what it weighs if you carry it to your car and then use it within 10m of your car when you get there. Edit: Also, yes you do need to check collimation every time the scope is transported. Its easy to bump it to things and if your roads are bumpy then its not even up to you to do the shaking. But this is not rocket science and a step you need to learn anyway with a newtonian, collimate your scope perfectly once indoors with the secondary mirror correctly centered under the focuser and from here on out its just a 1 minute process with a laser to adjust the little things that have shaken out of alignment during transportation. For carrying the kit, look at Oklop branded bags, i have one for the scope and it makes carrying the thing much easier.

20 is way too low, stick to the default 768 offset to make sure no pixels are at 0. There are no real world downsides to having that extra offset as you can afford to lose that few hundred ADUs from the 65k the camera has to work with. Assuming you are using HCG mode too? If not, maybe better to, as LCG mode has limited benefit compared to HCG and only in some very specific situations (if you dont know you need it, you will not need it or benefit from it). It doesnt really matter if the images come out good or not, 0 value pixels are physically impossible to calibrate properly and you will have problems with flats and darks calibration if you have them (cant divide or multiply by 0 so software used for calibration uses a very small number, like 0.0001 or something, but not 0. Its a problem because the real pixel value could be -100 or -200 but there is no way to know since it was clipped). I would still recommend taking all darks indoors with the camera off the scope and completely covered as just a few photons creeping in somewhere will ruin them. As for why this happened, not sure. I have noticed that sometimes immediately after shining something bright down the tube, like a flat panel, the next frame will have some ghosting of signal as if the light was still partially there. This is always the first shot after, so was your failed one the first darkflat after taking the flats? Dont know of a solution to this, other than checking each first shot of a sequence when taking darks but for what its worth this happens quite rarely.

I set up on the car park as i cant carry the 60kg mountain of stuff far anyway. Not much traffic after dark and most of that is other astronomers. SQM 21 or slightly better skies to anywhere but north/northwest where the Helsinki nebula is still bright. South is obstructed to 25 degrees or so, which means M42 is not visible here. I have another common spot i use to the north: https://www.taivaanvahti.fi/locations/show/120 Since that is north of Helsinki it can be used to image northern targets better than the Kirkkonummi one. This is a less windy spot too, but not by much. Have had good seeing here a couple of times too. Also is a carpark so winter friendly. By the way since clouds have a warming greenhouse effect, once they go away the weather turns cold really fast. Shouldnt expect to have warmer than -10 clear nights befire spring and should expect to get many -20 nights in January-March so best get used to it if you want to image at all 😬.

You could bin the mono camera x2 and do a bayer split for the OSC which reduces image size to half, so the same size as the mono at bin x2. This way all of your data is mono and compatible easily so no faff in the compositing phase. Youve made great images with the setup as it is now so i dont see how it wouldnt get better with swapping one for mono. If anything it sounds like a very efficient setup, you get a full LRGB image per run.

That would be 6 months of oopsie cooldown with the pace i got mine. Apparently there were some health issues for one of his colleagues and that was partially to thank for the delay but its not an uncommon thing to read online. So best spend some time measuring for the cuts (and actually cut where measured, important bit).

TS in Germany claims delivery in 5 days: https://www.teleskop-express.de/shop/product_info.php/info/p11153_Celestron-Focusing-Motor-for-SC-and-EdgeHD-Telescopes.html I dont really believe these according to manufacturer type estimates, but its probably not a month long wait.

This place will likely have good seeing once/if the shallows close to shore freeze solid. Like it is now there will be a little thermals rising during the night so low elevation targets are probably not worth the effort. If its windy it might be good anyway. Not a bad horizon at all really.

Also, some forum usage tips. If you write a users name like this they will not see it in their notifications feed, i just happened to stumble on this post again this time. You can write "@" without the quotation marks and the name of the user you want to reach and it will create a mention like this: @muletopia which can be seen in the notifications. You can also click the "quote" button for a comment and that will send a notification to whoever wrote the comment you are quoting.

Does it give an error or a reason as to why it did not slew? The scope will not slew if there are limits in place, like the mount being parked in EQMOD, or if you have set elevation limits annd those are met. Usually NINA gives an error of some kind in case it doesn't do what you commanded it to.

Done and dusted, this time with rightly measured, rightly drilled to the measured places rather than someplace else. Perfect collimation and visually even looking vanes. Looks like my particular spider has a little bit unsymmetric attachment points of the vanes to the central part so may have been on a wild goose chase before with them. Have not noticed this to be an issue in the previous tube so doubt i will care in this one. I will also cover the old holes with velcro tape which i will use to attach a dew shield so nobody will ever know that i had some spider hole drilling practice 😉. Didn't lose any clear skies in the process, as have not had them for more than 5 weeks, and looks like the situation is not changing for this week either judging from the forecast of snow and warm winter weather. Only once winter really sets in with a cold front we will get clear skies here, this almost winter with barely below 0 is guaranteed full gray sky 24/7.

I dont have experience on either of the ones you had in mind, but i have an Askar OAG which i think is great value for money (and good quality otherwise). It is natively M54 and comes with threaded adapters to M48 and M42 for both the scope and camera side so you can fit it to almost any scope without extra kit. This one has a 10x10 prism, so a little bit smaller than the 12x12 on the 2 bigger ones. But on the topic of that, for your 290MM you definitely will not need to have a bigger prism and the 10x10 is plenty enough. Not so sure about the 174MM though as the sensor is a lot larger, but you might be surprised how many stars even the small sensor will pick up. While i dont image at 2m focal length so its not an exact comparison, i think its somewhat close. I am imaging with 1025mm focal length and 200mm aperture with a 120MM using just 3s exposures. So far i have never come across a situation where there aren't at least 5 suitable guide stars in the tiny little sensor with this short exposure. The 290MM is more sensitive, but has smaller pixels so i think it evens out in terms of usable sensitivity. I would be very surprised if you have trouble finding a guide star with the 290MM with sensible exposure times. The bigger ones are probably a safer bet if you do intend to buy the 174MM but thats a fair chunk of cash so you may want to think about that and try with the 290 first.

Yes i remember that, i was dreading the (w)hole process fearing i would somehow fumble with the big hole. I was almost neurotically obsessed with getting that right so must have spent all my available focus on that and somehow let go of the brain after i was done with it. I also see what you mean when you mentioned back that the tube is rigid, i am sure i could drill 10 focuser holes in it and would not notice a change in rigidity, this thing is ridiculously sturdy.

Pipe installment practice run in the end. I will definitely redrill the holes, looks like i also did not do them symmetrically enough and the spider has trouble having straight vanes because of that. 9mm instead of 8mm holes this time to give some adjustment room, and also this time to the correct place 😉.

Or drill once, as i did just now drilling holes in a helmerichs carbon tube where i will place all of my current VX8 to complete the un-VX-ing operation of the scope. I measured the holes in the correct places, twice, as the saying goes. Then just drilled them, piece of cake. Drilled the holes nicely too, not much scruff and bite on the easily biteable carbon tube so everything is clean looking. Just one problem though, even though i had measured the correct locations of all the holes i drilled 2cm away from them for the secondary spider so now the secondary mirror cant get fully under the focuser to be illuminated correctly 🤪. Collimation is still possible but one side of my APS-C sized camera sensor receives 15% less light and under the stars there will most likely be awful tilt issues with star sizes. So measure twice and cut once, but remember to cut where you measured instead of next to it 🤣. Thankfully not a huge disaster, just have to find or make my own collimation screws that are long enough to hold the secondary mirror further away. Thing is i already had quite long 45mm M4 screws as the VX8 had a similarly (almost as) far away drilled spider holes. This was one of the things i wanted to fix with the new tube, but for some reason i forgot that and actually made the thing worse. May have to drill new holes and call the earlier ones practice holes.

Hmm, maybe, but not qualified to say as have not owned a RASA type scope before. But the aberration itself looks familiar as failed newtonian flats also looked like that but its been a number of years since mine failed so bad as to cause that as i have fixed most of the issues. But when i was taking flats the next day or used previous flats they looked like that with a bright ring and some weird things going on on some of the corners. Is it possible something mechanical has failed like mirror locks, focusers etc? Probably not as the RASA11 is not exactly entry level kit and one would hope its mechanically stable.

Did not find the galaxy, but IFN pops up in a cropped field of view with a very heavy stretch so safe to say the exposure is already quite deep and the galaxy is seriously elusive: By the way, there is loads and loads of IFN and background galaxy stuff in the image for just 3.5 hours. In case you decide to sacrifice a couple more nights to it you'll get a killer IFN image out of it for sure, even if the galaxy stays hidden somewhere. Cropped feature from middle of the flat calibration ring artifact thingy (was easier to process the flaws out when cropped): Never had a chance to play with a full frame RASA 11 shot so this was an experience, thank you for sharing!