Trippelforge

Geez, I wonder why they are so loud? I have a dual motor Celestron kit and can't hear it unless I put my ear next to it. 

22 minutes ago, UKRoman said:

 

I've just today received an EQStar Pro for my old Vixen Super Polar is mount, directly from Astro Gadget. It's taken about 3 weeks to get here from Kharkiv in Ukraine. Quite frankly I'm amazed it's even got here at all given the troubles in Ukraine at the moment. Hats off to Alexander from Astro Gadget for carrying on in the face of all the challenges.

Obviously I haven't tried it outside yet, but I'm looking forward to the first clear night to give it a go. The kit is well made and easy to install, taking me about half an hour. There were no printed installation instructions with it, but if you know your way round a mount then it's pretty straight forward and intuitive. So far I've only connected to the EQStar Pro using the Synscan App to ensure the motors are working. Tracking motion seems to work fine and it's pretty fast when it comes to slewing. The only thing that's a concern (and hence the reason I've just been searching for posts on this topic) is the very loud variable whining noise from the stepper motors. I knew that all stepper motors were noisy even when idling, but hadn't quite expected this. For astro-photography it won't be an issue as I'll be inside anyway, letting the mount do its thing (and hoping it won't wake up the neighbours). But I'm not sure I could stand next to it for any length of time doing visual work.

If anyone can comment on how noisy their EQStar Pro stepper motors are, I'd love to hear your experiences.

Cheers

Wow... it's that loud? I wonder if that's normal... did you reach out to AP and ask?

Glad to hear it seems well made and easy to use. I contacted him about the Ukraine situation and he said his company was located far away from the chaos. 

On 11/11/2022 at 09:28, PeterC65 said:

EEVA is Electronically Enhanced Visual Astronomy. It's sometimes called EAA, Electronically Assisted Astronomy. Another (older) name for it is Video Astronomy.

Basically, it means using a camera instead of an eyepiece but viewing the image live, or close to live. I think the older term Video Astronomy means live, whereas today it is possible to do live stacking, so the images are processed but close to live. By "close to live" I mean anything from sitting in front of the laptop watching as the 4s exposure frames arrive and are stacked (this is what I mostly do) through to letting the software stack frames for 15 minutes and then taking a look.

What EEVA isn't is collecting data for hours, sometimes over multiple sessions, then post processing it much later. That is AP, Astro Photography, which is my opinion is a different hobby. EEVA is much closer to visual only astronomy (just using your own eyes).

I've just read your other post about how useful more stacking can be, and I think you should decide whether you want results on the night (EEVA) or the next day (AP). The kit you need for each is quite a bit different (AP is more expensive!).

I like a wide field of view when I observe visually. The first astro camera I used for EEVA had a 5.6mm x 3.1mm sensor and this felt like I was looking through a keyhole compared with the DSLR that I also used (22.2mm x 14.7mm). The DSLR is a pain in the neck (too big, too heavy, has a physical shutter, only runs off its own batteries) so I wanted an astro camera with a sensor about the same size as the DSLR. At that size they have relatively high read noise and are expensive for the better ones and that's why I settled on the mid-sized Uranus-C (11.2mm x 6.3mm). It's field of view is double that of my first camera but half that of the DSLR. So, I also have a x0.6 Reducer / Field Flattener which solves the problem. I've only used it once so far but it produced a great view of M31 (I posted a snapshot in this thread, page 6 about 1/3 of the way down, on October 21). Focal Reducers only really work with refractors though (I believe - mine certainly doesn't work with my Newtonian).

Since I bought the Uranus-C I've also realised that the bigger the sensor the more area the scope needs to illuminate. Some scopes struggle to illuminate a full DSLR sensor, and you get darker corners in the image (vignetting), plus the scopes inherent edge deficiencies (aberrations of various types) are worse the further out from the centre of the illumination. If you think about it, most scopes are designed for visual use where at most they have to illuminate a 7mm diameter human eye, so asking them to illuminate and remain in focus across a 27mm diagonal DSLR sensor is pushing things.

I ran everything through the AP tool and was pretty shocked at how much FOV I was losing with the Uranus-C. I then tossed on a reducer and saw how much I could get back, although making sure I buy the correct one has been a bit confusing. I asked around and it seems I just need to make sure it matches my scope specifications. Although many of the manufacturers are telling people that they won't work with anything besides their own scopes. 

Regardless I am solely doing AP, and targeting DSO's. I also am using a refractor (80mm) so it seems I am lined up in regards to a flattener / reducer. I have gotten SO MANY opinions across various forums on if I should or shouldn't pick up a Uranus-C. 

Obviously though you have been happy with the Uranus-C, I always felt like as a budget option it would be a nice upgrade over my old 500D, but a lot of people are kind of scoffing at the idea. So once again I got stuck... new DSLR, 1k+ AP camera... ugh

15 hours ago, PeterC65 said:

Bear in mind that I'm fairly new to astronomy but ...

You can use narrow band filters to select a particular wavelength and image only that one. This is how people use monochrome cameras I believe, using red green and blue filters to pick out those parts of the spectrum and sometimes narrow band filters to pick out particular emission lines. The seperate images then get combined, sometimes with false colour, in post processing.

You can use narrow band filters with colour cameras too to pick out the emission lines from a nebula for example. This is what I do with a UHC filter and an OIII filter.

Whatever range of wavelength you are collecting, the optimum focus point will be an average. Whether you can see blur in the imaged object will depend on the range of wavelengths being emitted and observed, and the degree of chromatic aberration in your scope. I've not found this to be a problem so far with no filter but a fairly nice refractor (an apocromatic with FPL53 glass).

I'm very happy with the Uranus-C. I would have probably felt the same about the ASI585. I'm glad I didn't go for an even bigger sensor as I think there would have been illumination issues and unless you pay four times the price there is nothing with such a low read noise. The next step up would be the IMX533 sensor, so the Saturn-C or ASI533, but the IMX533 sensor is only wider than the IMX585 in one dimension and not worth the extra cash I believe. Cooled cameras may be better for full on astrophotography with long exposures but they are much more expensive and I think it is diminishing returns.

I should add that I do EEVA and only take snapshots so I'm not after the n'th degree of perfection.

What does EEVA mean?

Thanks for explaining everything to me, I feel much more educated on the topic now. My main issue at this point is worrying about the FOV. I had no idea how small the Uranus-C was FOV wise until this morning when using the tool. So I have gone out now and started to research focal reducers to see if I can open that up a bit. 

10 minutes ago, Synchronicity said:

I've recently bought a ZWO ASI 183MC-PRO and my process was reasonably simple and similar to what you are doing. 

• I searched for that camera and the others I was considering in this forum and read what was said. 
• I searched https://www.astrobin.com for images taken with the camera and my scope - an Esprit 80.
• I entered the scope and camera spec into the Ocular settings in Stellarium and used that to get an idea of the framing and size of various targets I was considering.
• I did the same with the telescope simulator at https://telescopius.com/

For the detailed specification of the cameras I found that price was filtering them down anyway so the list wasn't too big!

HTH

Michael

OK so I am doing what people normally do. I think what kind hung me up a bit was when comparing two camera's not far apart and thinking "is it worth it?". And then running through the specs and not seeing much difference. 

11 minutes ago, PeterC65 said:

I'm still figuring this stuff out myself, but as I understand it, with refractor telescopes the focus position depends on the wavelength of the light and the wider the range of wavelengths the wider the focus range. So when using a camera, which is sensitive across a wider range of wavelengths than the eye, the lack of focus at extremes of wavelength can be noticeable. A UV / IR cut filter limits the range of wavelengths thereby limiting the extent of chromatic aberration and star bloat. Personally, I haven't noticed star bloat so far, and I've not been using a filter. I've bought the L2 filter to check how much difference it makes. There is a case for not cutting the IR since it is more light which usually improves the image, provided it is in focus.

Thank you for explaining that, it makes sense. Quick question, how do people focus in on a particular wavelength? With just starting out my only association with focusing is simply using a bright star. 

So in your final opinion the Uranus - C hasn't been a bad camera? I planned on using it as a budget DSO for now. My stupid 500D has been having some sketchy problems. But so many people in the other forums keep trashing them and pushing me to start out without something at the 1k price point. I can't afford that though. lol

I have been shopping around and trying to compare various dedicated camera's. Each one on say ZWOs website lists a bunch of specs along with a page of graphs. When I line them up I get a bit stuck when comparing. I understand that low read noise has a strong correlation with desired dynamic range. And when you line them up you find a sweet spot that falls on the gain scale. But that's where things start to get confusing, such as I am not sure if one location on the gain scale is better than the other. Such as if this (sweet spot) point falls around 180 gain, is it better than if it were 100 gain.

Man that probably sounds confusing... I hope it sort of makes sense. lol

My main curiosity like the title says is how are people comparing the various models? Currently I am trying to find reviews, looking up astrobin examples and scouring forums. But when I have bought anything else (even DSLR) I could just line them up and see pretty easily which was better. Which kind of works for anything you buy in life... however for some reason the CMOS camera's are hard for me to do so. Which is probably due to so many other "specs" listed.

Any advice on how to do this?

21 minutes ago, happy-kat said:

I have a very sensitive IR camera and if I don't block IR, focus is not as good. If I want IR then I change filter and block everything else.

Thank you that clears it up. Do you have the IMX585 chip? I am now curious if it would have focus issues without a filter. 

12 minutes ago, PeterC65 said:

Both the Player One and the ZWO cameras have AR coated windows meaning they let through all wavelengths. They both use the IMX585 sensor so I would expect their QE curves (wavelength response curves) to be identical, but the camera specs show some small differences which may be caused by different window materials.

QE curves differ mostly from sensor to sensor and those for the IMX585 are fairly typical.

Neither Player One nor ZWO seem to specify QE below 400nm, so in the UV band, but they are both sensitive in the IR band. At 400nm the blue response is falling but the red and green responses are rising so without a spec it is hard to know what the UV response will be. Have you seen something that specifies the response below 400nm? I'd be interested to know what it might be.

I've recently bought an Astronomik L2 filter to cut the IR band. I've yet to try it but expect it to reduce star bloat. I also have an IR pass filter, also yet to be tried, as I understand that IR imaging of the Moon and planets can reduce atmospheric distortion.

 

I just looked at their posted graph and noticed that's where it stopped. I did notice as you said that the red and green were still rising when they had hit the 400 limit though. But I obviously don't really know how that works (figured it was a cut off point). When imaging DSO's what is the reasoning behind blocking the IR band? Is it just not needed for certain targets / causes actually degradation of final images? 

20 hours ago, PeterC65 said:

The specs for the Player One and ZWO versions of IMX585 based cameras are almost identical, since most of the spec is dictated by the sensor itself. The only significant difference is the gain value at which the sensor switches from Low Conversion Gain mode to High Conversion Gain mode which I believe is set in software. For the Uranus-C HCG mode starts at a gain value of 180 (and above), for the ASI585 it starts at 250 (and above). When in HCG mode the read noise reduces and the dynamic range increases, both good things, so most people seem to operate their cameras only in HCG mode and largely ignore LCG mode. For this reason alone, I chose the Player One camera as it offers a wider range of useful gain.

So far in practice I rarely use gains below 250 so the HCG / LCG switching point is moot. Having bought the Uranus-C however, I do find the hexagonal case design useful, and it is well made (and well supported as I have recently discovered). I'm sure the same would be true of the ZWO model.

As others have mentioned, if I'd wanted to use an ASiair (ZWO computer used to control cameras, mounts, etc) then I would have bought the ZWO camera as it doesn't support other makes of astro camera. But I use a simple direct USB connection to a laptop.

Whichever of these cameras you choose, I'd recommend either. There is no amp glow so black is black and you don't need to mess about with collecting dark frames. The sensor size is quite big but not so big that parts of it don't get illuminated and you have to deal with vignetting. The pixel size is smallish so you can see plenty of detail with the right FL scope. The sensor takes 4K images which gives an amazing full frame image (lovely on a 4K monitor) and is enough for you to crop the image or just collect data from a smaller region of interest.

I started with a similarly speced camera but with a smaller (physical and resolution) sensor that suffered from amp glow, and I no longer use it. When I upgraded from that camera, I considered bigger sensor size cameras but settled on the IMX585 and I'm very pleased with it.

 

I have been digging into spectrum ranges due to learning that modified DSLRs list out various options. I also noticed the IMX585 seems to cut off prior to falling into the UV range (via it's website graph). Another user in a post said:

Quote

In terms of dedicated cameras some OSC will be full spectrum and some will come with a UV/IR or IR only Cut on their optical window, you need to read the fine print to know for sure.

 I don't see anything in the player one listing directly addressing that question. Any idea on the answer if the question is important?

While looking through various camera's I am coming across graphs showing the wave lengths of each. The one thing that stands out to me is how some are being listed between 400-1000nm. Which obviously does not allow the capability of gathering UV light. My entire thought process revolved around dedicated camera's having "naked" sensors. Which I based off of the fact that removing filters is one of the reasons people modify their DSLR's, in particular UV/IR. How does it really work, I assume I am completely confused!

14 hours ago, MichaelBibby said:

If your talking about the banding fault that Peter and myself had with the camera, I've already got my replacement. Customer service has been awesome. Apart from that, it seems like the main consideration on deciding between them (as others have mentioned here) is where the high gain cut off point is and how that relates to how you intend to use the camera. The only other small problem I have had a couple of times is a couple of frames being temporarily backed up in sharpcap during live stacking (10s exposures). But this has not been a problem at all and usually resolves itself pretty quickly. Not sure if this effects ZWO's camera, likely a firmware thing (actually, the problem might be with my computer or sharpcap itself, because I've also had the situation where the histogram wouldn't reset straight away but take a minute or so). Apart from that I'm happy with the build quality. (Can't say much else because I'm not experienced with astrophotography).

I was looking at all of the charts and not extremely educated on what a lot of it means. I know the basics, but something like "high gain cut off point" I do not (which is prob a basic, lol). My intention is to use it for DSO's, emission nebula, galaxies etc. I never considered these price point models as I got a lot of negative feedback on the mere idea of not dropping 1,000 bucks on one. But then I started to come across conversations and videos about how capable they actually are. 

Anyhow, I only mention all that due to hoping you might be able to tell me a few things to look out for as far as specifications. Like the high gain cut off, what value is the most important for DSOs for instance?

So what is the general consensus on ZWO vs Player-One in regards to the IMX585? I was looking at picking up a Uranus-C , but not so sure now.

That makes more sense, so your capabilities in general have to be pretty damn high in order to even think about the method. That would explain why some of the articles were showing giant hubble sized dobs... LOL

I have been recently coming across this term and had never heard of it before. I looked it up and read an article and my take away was that it pretty much is taking hundreds if not thousands of short exposure images. And then go on to stack them and throw away a lot of frames to avoid atmospheric aberrations for instance. A few of the examples I saw showed very detailed and impressive images. The head scratcher for me is how are people taking 1-2 second frames and pulling in enough data to produce anything, even with a massive stack?

I have no be confused on what it means, and the process though. 

Old thread but I have been considering the EQStarProEQ3 (for my CG4) as I can't afford a new mount. I currently have the dual motor Celestron kit that looks like it came from wish. 

So I was curious how everyone is doing with theirs today and if they are still happy with it? Also it's mentioned the guy is shipping out of Ukraine... I wonder how that's currently working out.

24 minutes ago, DaveS said:

Ideally your exposure times should be long enough to swamp the read noise by about 3x. How long this is depends on your light pollution, the read noise of the camera, and whether you're doing OSC, mono RGB or NB. The rather noisy CCD cameras that I use tend to need longer exposures, but CMOS can get away with shorter.

OK so there is a point when the exposure times are so long that read noise etc gets out paced by the "good" image data. I always had assumed that it worked the opposite way. Taking that into consideration I REALLY need to upgrade my motor drive system, 30-40 second crap isn't cutting it. 

On 06/11/2022 at 02:42, wimvb said:

Shorter exposures does NOT equate to less noise, because cameras have read noise, independent of exposure time. Longer exposures = less noise, or higher signal to noise ratio ("more signal per noise"). In theory, every time you double the total exposure time you already have, you cut the noise to 70%, as long as you've exposed long enough to drown the read noise. The point of diminishing returns is determined by perseverance, or just simply by you saying "that does it for me".

When we progress in astrophotography, most of us (including myself) go from shooting multiple targets per night to shooting multiple nights per target.

Some people pointed out that when stacking short exposures it increased the signal to noise ratio. So is that simply not true, or does the read noise pile on as well and make things worse unless I extend exposure time? I keep getting a bit confused, obviously I can simply experiment and see though.

My simple situation (as I probably mentioned) is that my son and I took a bunch of 30 second images. Our idea was to hit Andromeda for more 30 second exposures each night for additional stacking. Which obviously the thought process that the stacked image would improve over time. Taking into consideration of your explanation it seems signal to noise won't ever build up enough to become detrimental to the process. 

Sorry I have been getting somewhat confused, as is it seems that I am getting some conflicting information. 

On 20/10/2022 at 15:16, Swillis said:

You need to have 50 posts to get access to the classifieds section. Which you get to quicker than you might think. 

Although I notice you're US based so it might not be that useful as most adverts are UK or EU based. 

Not sure if cloudy nights has a classifieds section?

I has no idea this forum was UK centric. That explains why so many store links are not based in the US (lol). I came across one, but it's very disorganized in my opinion and hard to nail down exactly what you want. It's extremely active though and things that are decent deals sell instantly. I really like how easy this forum is to navigate and how clean it looks. I wish CN would get an update at some point (I am sure it won't).  

On 23/10/2022 at 18:31, edarter said:

With regard to a modified dslr, I would suggest one with an articulating screen. Your back and knees will thank you!

Ed

I use the PC screen so it may not be a huge deal for me? Or is there another reason why an articulating screen would be helpful?

16 hours ago, WolfieGlos said:

I have a stock 77d and a modified 800d; both have articulated screens, wifi and the same sensor.

The wifi works well for me, but it is a bit of a chore to get an image off of the camera, to the phone, to upload to astrometry to platesolve. Got my modified camera from astronomiser, http://www.astronomiser.co.uk/ . From the point of order, I had it in under a week. Superb service, highly recommended. 

So the wifi capability is only to a phone? My old 500 connects directly to my PC.

2 hours ago, Ouroboros said:

Looks not unlike my first set up which was Canon 450D on an EQ5 tracking (unguided) mount under similar skies. Mine was a faster scope f/5.

So the duration of your subs is limited by the mount and how well you can polar align. I reckon I was limited to exposures between 60 and 120 seconds when well polar  aligned.   Without a polar scope your 30 seconds might be about what’s achievable.

Then we must consider ISO. As this site puts it “There is an optimal ISO value for each DSLR, where your specific sensor provides the optimal balance between read noise and dynamic range.”  Read noise occurs each time an image is transferred off the camera. 

They reckon for the 500D the optimum ISO is 1600. For my 450D I know it is 400 or 800.

As Olly says, it’s better to take longer subs if you can (up to a point).  You don’t want light pollution to become the dominant signal.  But I think your limiting factor is the mount. If you can tweak the polar alignment to allow for 60 second or more that would be worth doing. 
 

 

I believe it is 1600, that is what I have been shooting at. I do have a polar scope and have spent a lot of time calibrating everything. Polaris stays on the circle line pretty dead on when I spin it, so I am hoping it's good enough. I had a hell of a time tweaking it though with those stupid tiny set screws (lol). 

However I do notice a tiny bit of trailing when I go over 40-45 seconds. It's very slight but obviously builds from there so I am not tracking perfectly. I don't know how to get it aligned any better though, however I can't rule out the motor drive (which I am looking to replace). 60 seconds might be doable though if I don't zoom all the way in on the stars and get critical. 

2 hours ago, newbie alert said:

Depend on the noise, light pollution and target brightness... There a few different types of noise which will all have an effect on your final image.. background sky plays a part in how much ( good) signal hits the sensor

Depending on how bright your target is, some targets are so dim that you won't get much signal from, so you can't build on signal if it's not contributing to filling the well..

 

 

 

Thank you, I will keep that in mind when we start going down the ladder in regards to magnitude. I suppose at one point we will hit a limit due to LP and need darker skies. The best thing I can get to is Bortal 3, which is about 3 hours away. Although I have already been planning a little camping trip with my son in order to do that. 

2 hours ago, Ouroboros said:

@Trippelforge Noise is quite a complex subject, as you might expect.  There are different contributions to noise in an image. Some of the noise is random and some is systematic.   We can point you at various sources of information if you’re really interested in getting into the subject.  But in the end it often comes down to a compromise in selecting the best exposure times that suit your equipment and sky conditions.

It would be helpful if you told us what sort of telescope and camera you’re using, and the type of mount. Is it an equatorial mount? Are you able to guide the mount?  What’s the light pollution like where you are? 

Sorry, I am not sure how to put a signature in my posts here. I noticed the about me section, but nothing else.

Barska 80mm ED @ f/7
Celestron CG-4 with tracking (non-connecting)
Canon 500D
Bortal 5

15 hours ago, newbie alert said:

So you have 30 mins of data...  You will get a far better image if the integration time runs into a good few hours.. the idea of stacking is to add signal above the noise from the camera.. so the point of deminished returns is by far in the 10's of hours

Shorter exposures = less noise, so a ton of shorter exposures will keep building up the image. If I try take longer exposures the noise will increase to the point of not getting as much "good" data out of each frame.  So if I am understanding right it's all about balancing and 2 hours vs 30 minutes will net a better image. So I probably should get more. Sorry just trying to make sure I am understanding. 

15 hours ago, Ouroboros said:

The statistical mathematics of this is that noise is proportional to the square root of the number of samples.  So you have to image for four times longer to reduce the noise by a factor of two.   So one would expect the average of 60 x 30 second sub images will have a noise level  of 1 divided by the square root of 2 times better than the average of 30 x 30s subs.

i.e. 

Noise of 60 subs = (1 / 1.41) x Noise of 30 subs.

There is a diminishing return of taking more and more subs. If you’ve already got 2 hours of data you have to image for 8 hours in total to see a factor of 2 improvement in noise.  In the end it comes down to how much time are you willing to devote to this image. 

Thanks for the detailed explanation. So "how much time" basically means I probably can keep going until I hit the diminishing return wall. Which I probably will notice eventually when the stacked image because crap. I told my son that we may want to move to Andromeda each night, and snap 15 minutes just because. And eventually after several hours may have a much more detailed result. I just didn't want to keep going into the several hour range if there wasn't much point.

My son and I took 30 x 30 second exposures of Andromeda. Once stacked the image we got was pretty amazing, so the assumption we had was that taking even more images would keep increasing the detail and quality overall. So we went out and took another 30 x 30 and stacked those on top of the others, tet we couldn't discern much in the way of any changes. 

So back to the title question; is there a limit or massive jump that needs to be taken to really improve the end result? Such as perhaps 30 more exposures isn't going to do much, but for example 90 more exposures should?

Hopefully that makes sense, as I always assumed gathering more and more images could increase quality.  

1 hour ago, ONIKKINEN said:

Pretty sure its that extra second or so that the mirror takes when flipping up or down at the beginning and ends of an exposure that ruins the timings. NINA will think the exposures go back to back without delay and after a few exposures your actual exposure schedule and what NINA thinks is happening dont match and you get timeout errors. In live view the mirror is kept out of the way so the timings match.

Do you think setting a delay between images might help? I am just concerned that live view always being on will run down my battery faster. If I have no choice I guess I will need to go ahead and buy a power adapter.  

12 minutes ago, spuduk said:

I would try a new usb cable. I had issues similar which turned out to be a cheap cable.

I know this cable is cheap, I found it randomly in my house. I actually kind of want a longer one so I guess it wouldn't hurt to buy a new quality one. Thanks for the suggestion!

8 minutes ago, ONIKKINEN said:

Similar timing issues with my 550D, try this:

Put the camera in manual mode with the exposure set to bulb. Turn live view on, and only then connect to NINA. Make sure that all delay shooting modes/mirror lock things are turned off from the settings too so that these dont ruin NINAs frame timings.

When swapping batteries you need to disconnect the camera, shut down, and then replace and reconnect.

Almost positive that it's already set in manual mode, with bulb (but going to re-check). Live view however is not on, just the settings screen. I have not really tweaked a lot of settings in NINA. Just made sure my ISO was correct. I will check the other options you mentioned tonight. So by what your saying there is some kind of conflict with NINA trying to also control mirror lock etc? That might explain why I didn't have problems with Backyard. 

Thanks for the help, I will mess with it. At the very least it's good to know that I am not the only person with issues.