ONIKKINEN

Interesting weather related observation here: Now that everything is covered in snow here i noticed that skyglow is CONSIDERABLY worse than it was just a while ago. Snow acts as a reflector for light pollution and basically all lights are shining directly to space. I would estimate that bortle ratings went up at least by 1 class, possibly 2 classes in some places. Not that i have had proper time to confirm this, just a few glimpses through gaps in the eternal early winter cloud cover.

1 minute ago, Louis D said:

Sounds like you'll do fine with those eyepieces.  You might want to add a 1.25" Barlow to get to higher powers without breaking the bank.  I won't make any used recommendations because I'm sure the Finland used astro market is nowhere near as robust as the one here in the US.  Others on here could probably recommend a current production Barlow of high quality for a decent price.

Used market does exist, but since the userbase is quite small there usually aren't that many interesting listings. But i do have a TS optics apochromatic 2.5x barlow (https://www.teleskop-express.de/shop/product_info.php/info/p55_TS-Optics-Optics-TSB251-2-5x-Barlow-Lens--1-25-inch---apochromatic-triplet-design.html) .

Performs well, or at least has performed well with any eyepiece in it so far. Also had a shot at imaging the planets with it and cant fault the apparent quality. I am pretty sure its the same as the GSO 2.5x barlow as they look pretty much the same but with a different brand etched to the side.

Part1 of my purchases has just arrived: APM 24mm ultra flat field 1.25 inch barrel eyepiece. Might be able to test this tonight as the weather is 50/50 right now and every weather service seems to disagree what happens in a few hours.

Part2 was not in the budget anymore since i had to use the money elsewhere, but since FLO is scheming against all the wallets of the northern hemisphere i ended up ordering a Pentax XW 10mm from the current sale 😃.

Still not sure what focal length eyepieces i should have gone with, but if i would never buy anything if i just kept thinking about this, so these are the ones i ended up with. With these i get 35x and 84x, which i think i will be using quite often. TeleVue eyepieces maybe one day, but for now these will do.

13 minutes ago, Chris said:

 Just to check we're simply talking about saving as 32 bit in DSS rather than 16bit right?

Yes, a 32bit rational format. DSS actually does all of the background stuff in this format already, and the autosave file that is automatically created is in 32bit rational (which is floating point, the subject of the linked other thread).

I am curious how big of a difference it is in your case as the subs themselves appear already stretched, but by stacking 40 subs with initial 14 bits you should be getting a 21bit depth final product if im not wrong on the math part. That means saving as 16bit will have the image be compressed from 21 effective bits to 16 bits = 5 bits of precision are lost.

52 minutes ago, Chris said:

Well this is the thing like you say, when using DSS and going straight to GIMP you need to stretch the data to see something that you can actually work on. I probably should get another Canon camera for tutorials though because the Fuji has some weird quarks: one of which is that when you import the stacked image into GIMP it looks super bright like a flat panel, whereas a Canon camera looks much darker and you can hardly see anything. I had to move the histogram to the left in DSS to make it usable in GIMP, but I've provided both the RAWS and master tiff so people can take the process from the start if they wish. I recommend they use the slightly tweaked master Tiff though as working with Fuji RAW takes some getting used to in DSS.

My point on the typical-black-image was that such an image has all of the signal in a very tight area of the histogram when linear, unlike the example here which is actually quite bright. My shots with either a DSLR or now an astro cam always have all of the faint signal (nebulosity, the thing i want) within the first 500 ADUs or so. ADU = analog to digital unit which is a fancy way to say pixel value. On a 16 bit image which is 2^16 you have 65536 ADUs or posssible brightness levels of a single pixel (per colour channel). If all of the data excluding star cores and cores of galaxies is within 500 values, you essentially get less than 1% of the dynamic range of the 16bit depth to work with. When this is stretched to cover more of the histogram, say to cover all the way to 22k or about a third of the way to the right you now have stretched the initial 500 values to cover an area 44 times the range! This will definitely lead to the sharp brightness gradients and the image will be mostly unrecoverable. Using 32bit precision you get a ridiculous amount of precision, billions of ADUs i think? With that, you are no longer limited by the data precision, but the amount and quality of subs captured. @vlaiv is the master of explanations on the matter and i am mostly parroting what i have read from the man 😃. See this recent thread on bit depth:

If the conversion process from Fuji to TIFF is weird somehow and alters the histogram, then im at a loss. What about shorter subs, like 30s. Are they as bright? 120s subs from light pollution could also just be too much and that's why everything is far too bright. The long subs required for astrophotography is actually mostly a myth these days, probably also applicable to the Fuji. Cameras are getting better and better and most times subs under a minute in light pollution is more than enough. Scouring around the internet some people claim that the XT-1 raws are supported by DSS with no conversion to TIFF first? Wouldn't know if that's true though, worth a try?

Still, try stacking in 32bit. There should be a noticeable improvement. If i try to follow the tutorial on my very dark stacks converted to 16bit, i get a horrible mess with sharp gradients between bright and less bright parts as a result. What the stack looks like doesn't really matter, as stretching will bring out the detail in the image. That is if there is enough bit depth to do that.

One of the biggest strengths of Siril is that there is a "preview mode" where you can preview the image as it would be if it was stretched (autostretch mode or histogram mode for full range) but keep the pixel values unchanged in the background.

Edit: and i also got an almost entirely white image from the 17 stacked subs in DSS. Black point adjustments made the image normal-ish looking.

I have the Omni 2x and cant really fault it. The construction is a bit simple but i don't think it needs to be all that fancy, it does the job just fine. I have another, slightly better "apochromatic construction" barlow (2,5x) but honestly im not sure i can see the difference. Simple construction = low weight so might actually be preferable for the 150p heritage. The 2x is also good magnification wise, i don't think you would benefit from the greater power of the Baader 2.25x. The 10mm in the barlow will get you 150x, which is probably enough for the small dob. Remember that as magnification increases, you also increase vibrations and other wobbles in the mechanics of the telescope itself so you probably don't want to overdo magnification.

And welcome to SGL!

Hope you don't mind some criticism of the process, but i have to comment. By the way i like the video as content and your videos in general, but as a tutorial this one sets bad examples (IMO). Noticed a few glaring issues right away that in my opinion should not be told to beginners, dont get me wrong its easy to understand and better than going around processing blind and with no instructions, but better alternatives are not more difficult to do! These things took me unnecessarily long to unlearn when i finally jumped to SIRIL (free!) to do the linear part processing. The final part that you mentioned in the video of processing always turning up different is born of these bad practices, and goes away with a few easy methods done early on.

The problem with processing entirely in "normal" processing software is that you need to stretch the image first to see anything, when ideally a lot of the processing is done while the data is still linear. In Siril you can do the first steps: crop artifacts out, background extraction (gradient removal attempts), color balance (important in linear phase to have as much precision as possible) and then stretch the image. From that point onwards processing in Gimp or any other "normal" software is a piece of cake. Its hard to do the first steps wrong in Siril, but very easy in Gimp, which is why you have different results every time. Playing with levels and curves early on is also not a good idea and should be done on the almost finished image as a final touch up.

First of all, this example shot sort of works because you have a supernaturally well visible picture straight out of the stacker! Personally i have never seen anything but the few brightest stars straight out of DSS and people who have similar almost black stacks will not be able to work with this tutorial. If you had a typical black/gray/brown image out of DSS the processing would not work at all because: The stack out of DSS in your case is in 16bit, which results in poor precision and separated values of pixels like shown in the first levels stretch section at 2 minutes onwards (the spikes in histogram values). This detail is unrecoverable and will result in a "choppy" final image as there is no precision to draw detail from. In your video you can clearly see the overblown parts do not smoothly transition to the less exposed parts but have clear separations of pixel values. The stack should always be in 32bit, there are no downsides! I am not Vlaiv but i think i have read enough of his comments to catch the 32bit good, 16bit bad vibe 😁. By the way it does not matter what bitrate the capture camera was, stacking multiple subs increases bitrate and 16bit is just not enough.

Stacked the 17 frames in the dropbox (should it be 40?) myself and found that it produces a very overexposed image, Looks like the core is lost along with the starcores of most stars, not related to the video but taking shorter subs in the first place remedies this. Also i found that photometric color calibration does not find any suitable stars in the image, this usually means the data is already stretched or woefully overexposed, both are possible but i suspect a stretch looking at the histogram. Did you stretch the images or modify them in any way in the Fuji to TIFF conversion process? Modifying single subs in any way always leads to lost data, especially if there is any kind of stretch on them.

In my opinion the sooner one learns to not do all of the processing in Gimp or Photoshop the better and Siril is a great tool for that. Very easy to learn as it only has a few features but extremely helpful!

Stellarium measurements can be missing completely or outdated as new data comes in. Gaia is working hard on rewriting many distance measurement so these things can change quite a bit.

When i try looking up distances to galaxies in my shots i often have to resort to NED: NASA extragalactic database for any information of the target. For instance NGC 2614, a galaxy in Camelopardalis has no distance info on Stellarium or Simbad, but has one in NED: http://ned.ipac.caltech.edu/byname?objname=NGC+2614&hconst=67.8&omegam=0.308&omegav=0.692&wmap=4&corr_z=1

1 hour ago, ollypenrice said:

I recently responded to another thread in which the OP had used plate solving to make a mosaic and couldn't see why his two plate solved panels were rejected by the stitching software. When I applied them over my own image I got this: 

Although it was a young thread another member had experienced something similar. I have two reactions to this. 1) Plate solving clearly didn't just work for these members. 2) More importantly, an imager actually looking at their captures would see that the two panels were not going to overlap. If software encourages us to 'disengage brain' then this cannot be a good thing.

I've participated in a 35 panel mosaic in which no plate solving was used at all. Therefore it never went wrong. 👹

Olly

 

That i agree on fully, never blind trust that a setting works because "it should".

In the case of your example either the tolerance was too sloppy, overlap was too little and/or rotation was ignored. The last part is definitely true, and also a mistake i have done myself. Preventable mistakes if one pays attention.

24 minutes ago, ollypenrice said:

I've never been persuaded by DSLRs as the 'obligatory' entry route into imaging. CMOS astro cameras are way cheaper than were CCDs and, alternatively, older CCDs are now cheaper on the used market. Personally, I don't think the case for starting with a DSLR has ever been weaker. This will make mine a minority opinion but it remains my opinion!

I'm also of the opinion that the less you do via software, the less likely you are to have problems. Things like plate solving are fine when they work but, for heaven's sake, do you really need software to point at your target? I'd consider introducing it when you're up and running but the priority is to get nicely guided, nicely focused subs in the can first. Don't become a computer-maniac!

lly

I really fail to see how platesolving can be anything but a massive time and headache saver. If guiding is already setup, clicking auto center in NINA is just a single button away. Actually 0 buttons if the sequence has auto centering on. Now of course you need to download the star database and point NINA to it but not really difficult and only done once.

Think of the time saved not doing: star alignment, framing, centering, all manually and every time you set up the gear. Star alignment with an eyepiece: not that difficult, star alignment with just cameras: nightmare. 

I do understand the dislike for software but platesolving is one of these things that "just work" when setup.

Something not mentioned already would be platesolving, i dont think that was a thing 10 years ago (not mainstream anyway).

With a guiding setup and a computer of some sort you can platesolve and auto center targets with many different software. Basically click a button and have perfect go-tos to anywhere in the sky. Never have to do star alignment again. Polar alignment can also be done with platesolving, polaris visible or not.

I doubt i would have noticed or mentioned the walking noise as a problem if you didnt point it out, it looks great!

But yes more data should reduce noise nicely. Or binning, or both? The walking noise is really subtle and on its way out, i reckon 2 more hours will drown it out as long as there is enough dithering.

4 hours ago, Captain Magenta said:

I have an AZ-EQ6, am also AZ-only, and like Stu's mine has carried some slightly crazy loads, without ever giving me problems. The SW blue-tube 300p newt shown came in at 27kgs! I would suggest that the tripod makes a difference too, I fairly quickly got myself a Berlebach Planet.

 

That thing really makes the mount look small 😅

2 hours ago, Enceladus Dan said:

Further updates, I adjusted out as much backlash as I felt safe to do. The tight side of the worm was marked on a sticky label on the slow motion control. It left me with just under 180 degrees usable. 

I orientated it so I can put the usable area inline with the worm carrier bolt as a reference. It felt much better and after calibration I ran the guide assistant which managed to complete the backlash measurement. It came back as 20,366 ms with a recommendation to guide in one direction as mentioned by Onikkinen. 

I guess that is a little on the large side so I’ll contact FLO for recommendations as the mount is still relatively new. 
thanks for help and guidance everyone. 
 

regards

Danny

20 seconds of backlash is pretty wild... If possible definitely have a chat with the supplier if there is something they can do as that should be fixable with a new worm, unless there are some other issues at play also.

I have one of these: https://www.amazon.co.uk/fenix-HM61R-Rechargeable-Magnetic-Headlamp/dp/B082DGTZVG/ref=sr_1_12?keywords=fenix+head+torch+hm61&qid=1638488003&sr=8-12

Impossible to break, rechargeable battery that never seems to run out and has a very low 1 lumen red light mode for astronomy that lasts 400 hours on one charge.

Consider giving SIRIL a try. SIRIL is a free astro processing software that is very simple, effective and easy to learn (as there aren't that many functions). Color balancing with SIRIL is as easy as a couple of clicks with the "normal" mode and will work most of the time much better than manually fiddling with sliders in PS. The photometric color calibration tool however works every single time and makes the colors as real as they can be, since the data is from actual photometric surveys. With photometry the only way colors can turn out wrong (is there such a thing? Maybe not) is with very noisy data that the photometry does not apply well to for some reason.

In my opinion pretty much all of the YouTube tutorials about processing entirely in Photoshop are to be avoided because they make no sense at all. Photoshop is a powerful tool after linear processing (backgrounds, colours, stretch) has already been done.

You could also try putting a layer of gorilla tape or other strong but flexible tape on the contact surface. That should nicely plug the gap and be easy to re apply. That is if it bothers you enough to try and fix it.

3 hours ago, Peter Reader said:

Just checked with digital callipers: 0.4 mm difference between width of mount boss and the tripod recess. Disappointing for a £1,300 bit of kit...

But really this problem is just one of the signs that show the price it was made for, there is a good reason why "premium" mounts are 2-3 times the price of these common mounts.

I have an EQM-35 and while a very different class of mount this also happens and is unavoidable. There are just 2 connections between the mount head and the tripod, the central bolt and the azimuth peg and if the machining tolerances for these are less than perfect (of course they are) you will always have some motion to some direction. In your video you can see that its not actually a rotation around the central bolt axis but a tilting/panning motion to the left. The azimuth peg prevents rotation, but does nothing to prevent the central bolt-mount connection from moving in the hole itself to and from the direction of the azimuth peg even when really tight. The best you can do is just tighten everything as good as can be and leave it be. Shouldn't be a problem in operation since there are no loads being applied to this direction when the mount is slewing/being used.

Just ordered an AZ-EQ6GT which will be arriving within the next, well who knows when new stock arrives? I will be using it for both visual and imaging so probably will be using both modes, but looks like both modes work well with users of both/either here.

One question for owners would be how much of a workout is the mount to assemble and carry really? I would be setting up and tearing down every time so it is a bit of a concern for me. Not that it matters since its already on its way but would be interested to hear from owners anyway. I reckon i will try to to put it in some sort of bag to carry it around rather than hug it to and from but it might be too heavy for that.

On 22/10/2021 at 10:15, Stu said:

I’m in exactly the opposite situation as the first two posters, I never used my AZEQ6 in EQ mode. I’m purely a visual observer so find AltAz much more convenient as it keeps the eyepiece in the same orientation as you know.

I assume you would either be imaging or observing in any one session? You may find if doing a lot of AP then you end up leaving it on EQ mode so as to keep your PA reasonably accurate and only requiring tweaks.

In my experience it is a very capable mount, far more so than the AZEQ5, and it carried some fairly crazy kids when I was observing with mine. This was a C8 Edge and a 150mm f9 apo doublet weighing 20kg! Must have been the hot summer, looking at the grass. 2015.

This looks like way too much telescope for the mount but if it works i reckon it will eat my 8 inch newtonian for breakfast 😅.

You still have time this year to observe Jupiter, although it is quite difficult due to the seeing. Good seeing tends to be more likely long after sunset, but Jupiter is also gone long after sunset so its a bit of a gamble whether you get good views anymore or not. Below 15 degrees the views will be increasingly worse very fast with each passing degree of altitude lost. Jupiter is at 15 degrees at best for me now and its been a long time since the views were good and usually its just a shimmering mess with no real detail to observe. Collimation issues also possible but since the moon looks great i wager its just the atmosphere in the way.

I don't know about the halo, but i would suspect reflections somewhere between any of the lenses in your comacorrector(?), filter, sensor window and the sensor surface itself. The brighter the object the more likely these should be and many pictures of this area have such halos.

The split diffraction spikes are caused by a twisted/unsymmetrical spider and can be difficult to fix. Straightening out the spider veins is a huge pain and its not that easy to see visually which way you need to bend and what when you're fixing it. I had this issue with my VX8 and fixed this by just replacing the very thin but also weak spider with a sturdier one. The new sturdy spider doesn't buckle under tension to any direction and certainly doesn't deform easily. I still found it difficult to do the final adjustments by eye, so i took some pictures with my phone and overlaid some lines drawn in MS paint to make it more visually clear what is bent and to what direction.

Much easier to see the direction of the bend at a glance like this!

Do note that centering the spider symmetrically can take it out from under your focuser if the borehole has been drilled incorrectly. I fixed this by shimming the focuser (tilting it basically) so that it faces the newly positioned spider head on.

15 minutes ago, Sunshine said:

There are some things which I always thought were absolute irrefutable facts until, someone explained why said "fact" it is not true. 

My experience so far in astronomy is either climbing up or falling down Mt. Stupid. Every day i learn something i did not know how little i understood of. Hearsay and myths are easy to circulate but facts are not so much, especially if the facts are difficult to understand and a convenient myth explains it in a simple (false) sentence.

Looks great, i always like seeing less common galaxies.

Is the galaxy cluster at the bottom left of IC 1727? Looks like there is something very faint.

I was thinking about this a bit more, do i really need the 24mm? I would get a magnification of 35x, compared to the 44x that i get from my existing 19mm that i think is too bright in terms of background. Most often i am observing from Bortle 6-ish or if im up for a quick view at home it would be a typical city sky hellscape of B8+ so a brighter background is not what i really want most of the time. Also, the 63mm secondary mirror giving a 30% obstruction might make an appearance at this low of a power. I think i can see a shadow of sorts with daytime use with the 19mm, so i would assume the effect gets more noticeable at even lower powers.

I could live without having a wider fov as i can see pleiades with the 19mm fully already, so perhaps the panoptic will have to wait. But what i am missing is something between 44x and 93x which is quite a jump. Also, the 9mm that gives 93x doesn't see much use without a barlow as its mostly a Lunar/planetary eyepiece for me. The TeleVue Delite 11mm or 13mm would be right around the missing ranges and from what i can gather vacuuming up from a million threads here and at CN they do work for faster scopes. Also, they are quite a bit cheaper than some of the other televues. 62 degrees sounds just fine, perfectly viewable comfortably and not too low. I should also note that the 0.95x maxfield corrector is not perfect to the edges, so wider fields might not even be that desirable. Choices, choices...

1 hour ago, Ricochet said:

I also used my Vixen SLVs (4, 6, 9) and I thought they coped very well at f4.4 and would be a good "budget" choice if the 50° field is acceptable to you. The 24mm Panoptic was stunning in the scope from centre to edge and would be an excellent choice if you can afford it, but will likely make you want to upgrade all your existing eyepieces. 

I dont mind the lower FOV at all with planetary and Lunar close ups, so i might just grab one of the Vixens for a high power eyepiece since they are quite affordable. The last bit is what i am a tiny bit afraid of, since its happened on other equipment already but i think this is just how this hobby goes 😁.

16 hours ago, Stuart1971 said:

I thought this version had the heated window, it’s shown on Aliexpress as having it…??

I personally have not noticed fogging of the sensor window in very humid weather. Apparently this is one of the things where your mileage may vary.