ONIKKINEN

Try out NINA which is free. Somewhat easy to use (for an astronomy software 🙄) and works well with my 550D.

Only done one deep sky mosaic so far, with APP.

Was fairly straightforward, put all the subs and the calibration frames in and APP stitches them together into a single stack. Takes forever though as APP is quite slow for some reason.

Brightness of the target is a decent metric, but only if taken into consideration with its size - for example M101 is brighter than M51 at mag 7.9 compared to mag 8.4 when considering their total brightness over the entire object, but M101 is much bigger in angular diameter so that light is spread across more pixels = its actually fainter! (by a huge margin).

Cant remember off the top of my head if NINA has surface brightness in magnitudes per square arc-second in its sky atlas, but the PC downloadable version of stellarium does.

What surface brightness you can image with a reasonable integration will depend on your gear and i wont guess where the limit is but once you image a target with a suface brightness of X you know you can image all the other targets with similar or better surface brightnesses.

And framing obviously is important. I dont think the crab would turn out that well with 200mm fl and 50mm aperture.

I would not worry about that difference. If your histogram peaks for all the colourchannels are somewhere around 30-50% then all good, but most importantly if the flats actually work. So you can test this by just applying the 3s flat to a sub and see if you get good calibration? Probably works just fine.

The most amazing thing about this IMO is:

Quote

There is a possibility that Nasa will not find the source of the issue and instead have to issue software changes or use one of the craft’s backup systems – something that has been done before in 2017 when Voyager had to switch from its primary thrusters to secondary ones because of signs of degradation.

That a relatively simple space probe launched 45 years ago "might have to" use backup systems because some glitch appeared and it somewhat affects the function of the probe. Meanwhile here on earth a modern mobile phone will be borderline hazardous junk at 5 years of use. Absolute insanity that the thing is still working properly out there!

Did you calibrate the data?

There is overcorrection of flats and also dustspots still visible so flats have not worked at all. The colourchannels also have different vignetting, so maybe different collimations? That would mean each filter must have had their own flats after each session, or its a no-go in terms of flats calibration. As a newtonian imager this all looks very familiar if i didn't take flats during each night. The blue channel has dark halos around stars (no idea whats the problem with this, but also i dont know how to deal with H-alpha containing data so if its something to do with that i cant say yay or nay)

The data is quite deepfried like this and ideally you would calibrate and then stack again but if its an old dataset then maybe not possible?

You can try to bruteforce the background to be workable with: https://www.graxpert.com/ . I tried it and while it still needs some work to even out the background it probably will turn out to be an image if you work on it. GraXpert is the best tool i have used when it comes to flawed flats and deepfried backgrounds, really works wonders so give it a try (its free!).

GraXpert background removal:

Stars have odd colours when M51 looks ok to me (i did simple Siril colour calibration). H-alpha thing? Try to run GraXpert on each of the stacks before the RGB combination thing and see if you get a better image.

Take every major piece of kit apart to avoid damaging anything i would say. Especially things that are awkwardly shaped, like a camera jutting out from the back of a long refractor, or the side of a newtonian. Very easy to bump that onto a doorframe and break something. If possible put the individual items in easy to carry bags (like sports equipment/hockey bags) to make them easy to carry. The more difficult you find carrying them, the more likely it is you drop something and have an expensive oopsie.

That straight and even diffraction pattern around Phecda is the stuff of dreams for a fast newtonian. Beautiful scope and image!

On 17/05/2022 at 19:22, vlaiv said:

Indeed - do mind not only the spacing - but also how close you put the prism to main sensor.

Faster the system - closer it needs to be to minimize vignetting.

Simple calculation says that for example 8mm prism on a fast system of say F/5 - needs closer than 40mm if you want to avoid prism size stopping down guide assembly. Even at 40mm (in F/5 case) - there will be only one point 100% illuminated.

OAG really needs to be close to camera for best performance (and it works better with slower scopes in that regard).

Math feels like rolling a square barrel - up a hill - for me so not sure i would find the calculation simple 😬, but did i get the idea that a bigger prism would be desirable even with the tiny sensor as it will be sitting in a rather fast scope at ~F/5? My RA worm has some rough spots that undergo a large periodic error within a 10s or so time period so ideally i wouldn't have to push guide exposures too high due to prism size stopping the aperture for the guider making for dimmer stars.

Askar makes an OAG with a 10x10 prism, bunch of adapters and a helical focuser all in the box so looks like this might be the way to go.

2 hours ago, MarsG76 said:

 

Yes I BIN2x2 my 120MM mini.... As far as imaging goes, I dont see my self going back to guide scope again... once the OAG is setup as running... and thats not that hard to do one you do it a few times... takes care of flexture and you're guiding at the same focal length as imaging.
One important thing to note is make sure the OAG is parfocal with the camera, half the problems in not finding a guide star was that the OAG was not in exact focus, limiting to the brightest stars if not completely eliminating seeing any of them.

Im thinking of using a helical microfocuser between the camera and OAG for peace of mind. Id rather not deal with the headache of figuring out the exact shims required to keep it parfocal.

8 hours ago, MarsG76 said:

I'm using a ZWO120MM mini with a OAG on my C8 at 2032mm focal length, and I don't remember having a situation where I didn't find at least one guide star within the search area.
On my 500mm focal length refractor, I don't think I ever seen a starless field. 

If it works for 2000mm FL then sounds good for my plans.

2 hours ago, vlaiv said:

It actually makes more sense to use smaller sensor than larger for OAG.

This is because prism is too small to illuminate large sensor. I use ASI185mc - it is somewhat larger than ASI120 (8.6mm vs 6mm diagonal) - and it gets vignetted on my OAG:

I see, is this with an 8x8 size prism OAG? I dont have one yet, but the 8x8 ones are cheaper than the bigger ones, so another way to save cash right there.

2 hours ago, wimvb said:

If you plan to use the original asi120 and not the mini version, make sure that it will fit. On my scope, I had trouble trying to fit the asi120 between the focuser and the filterwheel. I bought the asi290 mini, and it just works. You can use it with the standard zwo oag. The 290 is more sensitive than the 120. So far, I've had no trouble finding guide stars in the fov. Multi star guiding doesn't always work, though.

Mine is the mini version, so i think it will work backfocus and size wise to any design of OAG, especially since i dont have a filterwheel.

I have played around with framing in stellarium and for most targets there appears to be a guidestar with little or no fiddling required, but nothing beats real life experiences, so im looking for feedback if anyone has used the very small sensor 120MM in a similar or longer focal length setup and how it went.

Looks like many use the 174MM for off axis guiding, but since i already have a 120MM and am not thrilled about the cost of the 174, would be convenient to be able to use the existing one.

The reported sky qualities are very rough estimates and the real life situation varies a lot, since you mention street lights nearby, its safe to say that the general measurements carry no weight for you then. If you want to really know what quality of skies you are under, you need to measure it yourself by either visually, using a sky quality meter (unihedron SQM for example) or by letting a software like ASTAP measure it for you using one calibrated subexposure.

Well, most of the time i dont actually go to a dark site, but just a site. But that sounds silly so i will call it a darksite trip even though the destination was Bortle 6 or 7. Over the past 2 years i have gone out with my scope roughly 50 times and thought it a good point to reflect on what i have learned to do and not do while imaging at a darksite. Plenty of mistakes were made and (i hope) learned from, so i am writing out a list of good practices and things to avoid so that others could minimize frustration and lost nights under dark skies. I have streamlined my setup process to a point where there are never any surprises and i am collimated, polar aligned, all software running, all trinkets on the scope and guide calibrated within 30 minutes of striking the tripod down. Bringing this time down is essential in getting the most out of a darksite trip, as time that you spend fumbling in the dark will result in no images and will just frustrate you, leading you to avoid these trips.

Purely mobile astrophotography without a backyard is perfectly doable even with quite heavy kit if you plan ahead and get used to it, for example i am currently imaging with an 8'' newtonian and an AZ-EQ6, so around 60kg of stuff with everything packed. The only real requirement for astrophotography is in my opinion a car and of course being in shape enough to handle the gear. (and the cost of course, but you dont have to spend as much as i have).

Most of the trip happens before you decide to go out, in the form of research and planning, so here are my tips for that.

1) Before even thinking of going to a darksite:

Make sure you have a good quality power supply! Most "dumb" battery solutions drop below 12V well before they actually run out of juice, making your kit unstable (especially in cold weather, dont bother when -20). I recommend pouring good money for a power supply that can supply stable 13.6V for the entire night.

Dry rehearse everything from packing the stuff into easy to carry bags or boxes and setting the gear up at home. If you cant do it easily at home you absolutely wont be able to do it free of frustration out in the cold and dark of night. If you have been imaging from the comfort of your own backyard you may have forgotten how to do some things, or have not given any thought on how to carry the stuff as it is relatively easy to carry even heavy stuff a couple of meters outside. Give significant thought on how you are planning on carrying your mount, which for most quality EQ mounts will be over 15kg of steel in an awkward chunk. Pack spares of as many pieces of small and easy to carry kit you may need, like cables that can easily break during transportation (pack them separately from heavy stuff to avoid this), fuses for your cigarette lighter plugged devices (the tip has a fuse!). Obviously dont bring a spare scope or a spare mount or something like that. If those break, time to pack up and go home.

2) Where to go?

Absolutely, definitely dont EVER go out with the intention of darksite imaging to a place you have not visited before! Have done that, wont do that again. You might find lights where you thought there were none, roads not winter maintained, or just something that makes the spot a no-go. Just check it before hand.

If you dont know of a local darksite that is well documented and you are familiar with, you need to do some research. https://www.lightpollutionmap.info/ Is a good resource for rough sky quality estimates. Do be aware that this is not set in stone and should be used as just a general idea of sky quality. Try to look around google maps street view mode around dark areas you want to travel to to find a spot that you could easily drive to and set up a scope in. After you have some ideas, drive to the site after dark before actually going imaging and check that it actually works for you. Google maps may be outdated and there may be street lights or new construction that has brightened the area, you wont know unless you actually physically go there at night. Pay attention to things other than darkness too, for example which directions are free of trees, obstacles and such. For example if north is covered you need to plan how to polar align without access to Polaris. Easy to do with many software out there, but almost impossible if you just figure it out when actually setting up! If the area is very open, like the edge of a field or an opening in a forest or something keep in mind that there may be wind. Try to gauge whether there is too much wind and dont bother using the location if the forecast has any significant wind in it to avoid a useless trip.

3) Target research

You HAVE TO know what you will be imaging before you go out or you will waste time looking at planetarium apps or imaging a sub par target. Knowing the target location already, keep in mind that some azimuths may be covered with obstacles (if they were in the spot you chose) and choose a target that is elsewhere. You may need to choose multiple targets for the night if your primary target gets too low in the sky as the night progresses. Also have secondary targets in mind if for some reason you find that you dont want to image the primary target. Reasons could be something like light haze making the data worse than what you want/have already gathered or poor seeing making a difficult target not work out. Be aware of where the Moon is and dont bother imaging your main target if the Moon is close to it. Just plan a target somewhere else in the sky for these situations.  Once you have the targets in mind, set them up as sequences before heading out. I use NINA and have a library of sequences that have exposure lengths, dithers, guiding, platesolving etc all set up and all i have to do is click "start sequence" and the scope does its thing. I have named the sequences ending in - Rotation 90 or something like that so that i know what rotation the camera needs to be in. Before accidentally shooting for half a night so that half the target is off screen (never done that...)

4) Packing and traveling

Check that each piece of kit is packed, then check again and pack the thing you forgot the first time. Try to minimize setup time by preinstalling as many things as possible, like: Keep the imaging train intact and if possible attached to the scope. If not possible, keep the imaging train as one chunk that you thread/insert into the focuser. Keep the guide cam in the guide scope and don touch the focuser, keep your mini-PC and the cables connected to that in a neat package that you just unfold when on site etc. Driving for an hour to somewhere and figuring out that you left an important piece of kit home is not a good time (have done, will probably do again). Give some thought on temperature differences with your kit as you will probably need to spend some time cooling the scope down when you arrive. If its winter and there is a 40 degree difference between indoors and the imaging location, you need to take steps to minimize the cooldown time on the way there so that you waste as little time as possible. I carry my newtonian in an Oklop padded bag, which also unfortunately acts as insulation and the scope will still be almost room temperature after the drive. This is why i open the bag once its in my trunk to let it cool down faster and dont use the heater in my car at full. Obviously the heater needs to a) keep me alive and b) keep the windows clear, but other than that just wear a hat and gloves and you'll find a ready to use scope when you arrive instead of looking at tube currents for more than an hour!

You may also want to pack visual astronomy gear if you plan on doing that. If you think that you'll "do some visual if you have time", spoiler alert, you wont. You need to plan on doing visual or it doesn't happen, at least if you suffer from chronic astrophotography as badly as i seem to do. This is a good way to salvage a ruined night if there is too much wind for example, as your mount will perform well enough for visual purposes in wind that makes accurate imaging nonsensical.

The best way to prepare is to leave all of your kit prepacked at all times in their carrying bags and not put them up for temporary storage between trips. Difficult to forget something like this!

5) Set up and beginning imaging

Do this the same way every time so that there are no surprises. For me it is: Plug in the cooling fan on my mirror to the battery pack to win as much cooling time as possible while i set everything else up, set up the mount with rough polar alignment to the north, scope and gear on the mount, polar align with sharpcap pro (Or NINA if Polaris is not available), guide calibrate on as low a declination you can, but still preferably at a high altitude. Not possible for me at 60 degrees north, so usually i have to settle for Declination 10-30 targets. Once its done, start the sequence, focus etc and off it goes. DONT "test things out" or "adjust" guiding if you didn't plan on it. If you need to iron out an issue with guiding, plan the session for JUST that or you will be frustrated on the wasted time and probably still not get the issue fixed. Check guide logs later and try to make guesses on what to fix, its much easier than trying to ad hoc a solution to a minor issue. If you have a new piece of kit that need testing, expect to not get any imaging done and you'll be less annoyed in the end.

6) Rules and showstoppers

Sometimes the weather just does a 180 and clouds appear out of nowhere even when the forecast said it would be 100% clear for the whole night. Have a set limit on how long you are going to wait for the clouds to pass and stick with it. If you wait for 30 minutes and "its just about to get clear", well usually it isn't and the 30 minutes goes on and on and on. Depends on whether its a good spot and a long drive but usually i wait for an hour and at this point the forecast should have changed to the actual conditions and now its much more clear on what the weather will be like. If at that point i dont see the clouds ending soon i head back home. Much better than just waiting for gaps in the clouds for the whole night! Accepting defeat is much better than the demoralizing wait for the clouds to end for hours and hours on end, trust me on this one.

Equipment breakages would also be something to keep in mind. Lets say something breaks and you dont have a spare. Just go home and fix it later, dont try to fix an issue you didn't prepare for beforehand. If you planned well and a cable, fuse, or something else easily replaceable breaks then great, fix that and keep going. Software issues are the most common culprits in my opinion to keep in mind. If you didn't check that every piece of software works with the remote setup then its on you and something to fix for next time.

7) Ending the session

You also want to have a limit on how long you are staying. If you plan on sleeping through the night, make sure everything is set up so that it keeps doing its thing without the need for babysitting. If you are planning on heading home after imaging and not sleep through the night, then have a limit set in mind. If you image to the bitter end of sunrise when you didn't plan to you'll be grumpy and tired tearing down the kit and driving back home in the wee hours. What the limit is will depend on your sleeping habits of course, but try not to ruin your sleep schedule too much or you wont be doing these kinds of trips out of annoyance anymore.

8 ) Try to have fun!

Sometimes easy to forget 😅.

TLDR ( wrote a wall of text...): Planning, planning and more planning will make your trips more efficient and less annoying.

Any rules, ideas, or tips come to mind? Feel free to comment your own experiences!

Depends on where the guide cam is i would say.

If its in a typical fast achromat guidescope, then yes you will benefit from the UV/IR filter. If its in an OAG in a scope that produces no chromatic aberration and has no weird IR reflection issues with optical surfaces, then no there is no need for one.

1 minute ago, Apprentice said:

Well I can say that AM130 is quite reasonable. I also use it on the azgti mount and have modded it with motor focuser, flocked the tube, placed a telrad, spotted the mirror, trying to find a DIY bobs knobs for secondary. 

 

 

I have absolutely zero interest in AP at this stage,  know the 130PDS has a better mirror, focuser etc. But trying to figure out if it's worth dishing out 200 euros and will it bring a significant improvment to my views.

AM130 has this issue with outer 15% being out of focus and having a really crap focuser

I am certainly watching the market for some improvement and looking towards 6"sct or potentially a better refractor. Of course that will have to wait, so was hoping this could be a quick fix and better views.

Oh, sorry i mistakenly thought this was post was in the imaging section when its not!

But i think the same points stand, actually especially for visual only. I found it really difficult to get ideal focus with my astromaster 130 because of the focuser and possibly because of the spherical aberrations produced by the primary mirror just not producing a sharp view. I dont have a 130PDS but judging from a thousand comments from users it cant be worse than the astromaster. I would be very surprised if on-axis performance wasn't significantly better with a parabolic mirror like with the one in the 130PDS, but not sure if 200€ better of course.

For imaging the primary mirror issue is actually not nearly as big of a deal when tracking issues and the atmosphere will probably be bigger sources of blur than the spherical mirror, but for visual with your own eye it is a big deal.

I could attach some raw stacks if you're interested?

Im afraid i dont have much good and easy to process data and most of my stacks are flawed in some way that may be difficult to work around, but that might be the case for your own datasets too at first so might be good practice.

I dont think the astromaster is suitable for AP at all, go for the PDS if you can.

The astromaster has a plastic focuser that is hardly usable for visual and will make consistent collimation impossible if you try to load it with a camera. The spherical mirror is also not really a fixable issue.

These look great for starter images and looks like you got the hang of it already. You'll improve your processing over time as you get more data in and try new things, but i dont think you should be worried about something specific going wrong right now.

16 hours ago, Fukencio said:

I have good equipment and Bortle 4 sky with light pollution filters

• Optolong L-Pro Light Pollution (for galaxy

I would drop this filter for galaxy imaging and your sky conditions. Bortle 4 is great and you wont benefit much, if at all, from using the filter on galaxies. With the filter you lose much of the colour palette coming in and so will have a difficult time producing a real colour result in the end (might be impossible). You will also cut the light coming from the galaxy itself with the filter, since light pollution and average galaxy light shares much of the same spectrum. For galaxy imaging i think its better to go without a light pollution filter and just deal with the gradients in post.

16 hours ago, Fukencio said:

So...my question is: Is there any place here in the forum or outside in where a Pro can take my raw files and process them to show me if the good data is there? or a service?

Many folks do this here in either the beginners section or the dedicated imaging section under the right category (deepsky-lunar-planetary etc). If you have a specific image you are not sure about, post it there and attach the raw stack preferably in .TIF or .FITS format and see if anyone wants to have a look? I dont think i have ever seen a posted stack that has had no downloads at all, many will gladly have a look at your data for free. Sometimes i see that there are no replies for these kinds of threads, but most of the time its because the image posted was already good, which i think is the case with your work too.

I also have an extra spike, but only sometimes. I have not figured out the cause and i have kinda just given up trying to troubleshoot it.

Focuser tube on mine is not obstructing the primary, there are no extra bits hanging in front of the scope or washing lines in the way. I suspect my coma corrector (TS maxfield) is the cause, but wont know for sure until i change it.

I had, and still somewhat have, significant cone error in my 8" newt and field rotation on a target at 74 degrees in DEC was definitely an issue. Best advice i can think of is to look into fixing cone error if you dont have the sensor area to spare to crop the corners out.

On 07/05/2022 at 23:58, maw lod qan said:

Saw on the internet the EQ6R I bought has gone up from $1695 to $2025 in six months.

Do you foresee it stopping anytime soon or is this going to be the new deal.

It sure doesn't make it easy on someone wanting to get into this hobby!

Mount prices have varied a lot in the past few years due to component shortages and probably other things so i wouldn't try to build a general price increase model based on mounts alone, but from what i can gather it seems that prices have generally gone up by about 10-20% depending on the kit in question. I dont really see this trend decreasing that much, if at all and dont think much of it.

If i couldn't afford an item before price hikes, the 20% increase means nothing to me. If i could barely afford the item before, saving up for the extra 20% is probably not that big of a stretch. My view on whats expensive and whats not has become really deranged since starting astrophotography so maybe that's why i dont think the price situation is a big deal right now.

The most frustrating thing has to be sudden shift in weather from clear to cloudy. I do mobile astronomy only so every time i want to set up my stuff takes at least 90 minutes until the camera or eyepiece is in place and doing work. I try to look at all the different weather services out there but lets be honest, none of them hit their mark every time. The times when i go out and expect a clear night only for the clouds to roll in AFTER i have gotten setup destroys me inside every time. Its really demoralizing and makes me feel like a complete clown. 90 minutes to set up, wait maybe 30-60min for the weather situation to become more clear and then tear down the stuff and head home without doing anything 🤮. I have gotten much better at judging weather in the past 2 years though and this problem gets smaller and smaller as time goes on.

43 minutes ago, Astro Noodles said:

No one has mentioned Starlink yet.

For my imaging they have never been a problem since sigma clipping removes all outliers even if there are a lot of them across the entire night. For visual its a nice curiosity if anything.