pipnina

I think anyone who suspects they suffer from SAD during the winter in the UK needs to look at vitamin D tablets if they don't already.

We need sun exposure to get the vitamin normally, so almost everyone needs it in supplement form and it can affect your mood when you become deficient! It wasn't a life changing difference or immediate for me but I could swear I suffered far less this winter than previously. It's supposed to be good to take for health even if you don't have SAD anyway, and 180 (half a year of) pills are pretty cheap.

As for astro... I know exactly what it's like to become disillusioned. For me it's the blasted weather. Months on end without the ability to get the kit out. A big struggle to get it all set up when the chance arises and, invariably, there will be technical issues! And because of the extremely limited time we get here to observe I feel all my images are left half cooked. I feel many of my images need 4, maybe even 8 nights worth of observations to let me truly get the image as clean as I'd like. But in this wet puddle of a country that is a year's fill of observations!

I have been working to sell my beloved triplet, simply for being both too big and too slow. f5.1 just won't cut it in this place. But telescopes are seldom made faster and the RASA is also very heavy. I am trying out a very nicely sized and fast Canon 300mm f2.8L lens, the 1989 version. I haven't had the chance to test it yet but I have my fingers crossed. In theory once I upgrade to a full frame sensor (either 2400MC or 6200MM - binned x2) it will be *faster* than an APS-C sensor on a RASA8.

I am pulling my hair out trying to juggle my kit and finances during this transition and experimentation but i have my fingers crossed that once I'm done I will have downsized my kit to the point where I can pick it up, plop it down and hit go, and even if I only get 1h of images it (should) have the SNR that my triplet+571 cam would achieve in 6 or even 12 hours!

1 hour ago, Celerondon said:

I see why you are confused because this story is as confusing as that picture. From your account, I can’t understand how the mount did anything after you parked it.  It is also hard to figure out how a GEM in the northern hemisphere tracked itself into the position shown in this picture. 
 

is there any way that someone or something could have slewed your HEQ5 into this unnatural position?  Doesn’t your mount park itself while pointed at the north celestial pole?  A tracking mount should rotate in the other direction and I don’t get why your dec axis isn’t aimed at the pole.   Kids, or cats, perhaps?

 

Don

I do have a mischievous cat however even his powers of destruction haven't affected my telescope yet. No kids to speak of.

I have only assumed so far that the mount or EKOS simply loses track of where the mount should be pointed... But why now after years of it working fine? Perhaps i need to look into mechanical issues as a struggling stepper motor or slippery clutch could maybe cause it to wig out?

52 minutes ago, ONIKKINEN said:

Sorry, dont know anything about EKOS/Indi, but something like this has happened to my EQM-35 and AZ-EQ6 when using NINA. So there is a chance this is a Skywatcher thing and not a software thing.

For me the weird wrong way slewing happened randomly and wouldn't go away within the night it happened. I ruled out different things and was left with only one option, the mount itself being confused by sync commands from NINA creating a bogus pointing model of some sort. At the time i used the USB port on the hand controller as a way to connect the mount to the PC, and a temporary fix was to factory reset the mount through the handset. Most likely not helpful for your case, different mount and control setup and all but thought to mention that a very similar thing happened with my mounts.

I don't know enough about the finder details of the skywatcher mounts under-the-hood operation, do the handsets act as the whole brain while the board inside the mount simply works as a stepper motor controller? If so It could be EKOS making alignment issues. If the brains are inside the mount then maybe I could plug my handset in and give it a factory wipe of some sort?

33 minutes ago, Elp said:

If you've parked and powered down I don't understand how this has happened. Was it off prior?

I always power up my setup pointed at the pole star with the counterweight pointing as close to straight down as possible. Usually the first goto slew will be off by some ten thousand arcseconds or so but the first platesolve will bring it within a few hundred, and by 4-5 platesolves it's normally in the 20 second tolerance I have set in EKOS.

I feel like I should have a security cam pointed at it (for multiple reasons) as I think many issues with controlling it from indoors would be solved if I could see it while controlling it!

Imaging was going well on M101 a few nights ago, but when it crossed the meridian EKOS/Indi or the mount itself had a wobbly performing the flip and it kept pointing in the wrong direction.

I went outside a few times to right it back to home position after hitting park in EKOS. It messed up each time. Eventually i hit park for the final time and gave up.

When I looked at it the next day I saw it like THIS! I had to perform a lot of careful maneuvers to get it out of there between the tripod legs! I have no idea how it managed it or how mount positioning could go so wrong... Could this be something to do with EKOS's alignment settings? I cleared them a few times when it was parked and also let it "sync" in the park position so it knew it was pointed at 88 degrees on DEC etc. It still refused to point properly.

First of all, my condolences! Rest assured you aren't the only one who did something stupid today... I will be making an "oops" post myself tomorrow.

It's possible you could buy a replacement optic from TS themselves, as they have a selection of telescope-building supplies including lenses:

https://www.teleskop-express.de/en/telescope-accessories-5/telescope-diy-improvement-299/telescope-making-optical-parts-91

Maybe there's even a triplet that fits your telescope OTA? Who knows.

For a small sensor I'd agree with the samyang. No direct experience but people's results with it that I've seen have been terrific.

I own a 135mm f3.5 canon FD lens for my AE1-Program. Even wide open it has incredible full frame coverage but just a bit of blue fringing that could probably be taken out with a UV-IR cut filter:

13 hours ago, ollypenrice said:

I discovered this when painting a steel handrail in front of the house. On a hot day it flowed out nicely.

Olly

Might explain why my hammerite application went so badly... It was 5c at the time!

2 hours ago, Peter Drew said:

Give it a good sanding down and then a coat of silver-grey Hammerite.   Available as a spray can     🙂      

I've used hammerite at work, sadly they bought it in paint pots and we were painting onto paint (valve handles needed to show what the valve carried by colour)

Brushing it on wasn't most effective... They looked a bit like a red tar monster when we were done haha.

1 hour ago, Elp said:

The thing with rust which I presume is on it, if it's on the metal it is extremely difficult to get rid of without some sort of real surface grinding and pre treatment, hammerite is supposed to cover the rust and metal but does it continue to rust underneath?

When I painted an area on a previous car, even when sanded down to bare shiny metal, a few coats of primer and a few coats of spray paint and lacquer, it still continued to rust a few months after. I suppose this application it isn't so exposed to the elements.

With paint you usually want a good keyed (textured) surface so there's something and more surface area to adhere to in the absence of an electro static process. Maybe use a coarse grit sandpaper to finish the surface prior to coating. You can always sand down with wet and dry to smooth it off afterward but needs a few coats of paint prior.

Bare mild steel will corrode very rapidly in wet environments. Rust is also supposedly self-perpetuating and a small amount of rust formation will crack or bubble paint allowing more oxygen access to the metal.

I suggest completing rust removal, preferably by wire wheel (you can buy them for home electric drill chucks, flapper wheel may also work). If you want to ensure it's moisture free in the cracks or pits you could always stick the metal in an oven at a skin safe temperature for a few minutes.

I need to think about all this myself, as my HEQ5 is starting to look a bit shabby with some parts of it rusting up and the counterweights losing their paintwork... Eventually it just catches rust and there's nothing you can do about it I guess. I suspect modern cars can avoid rusting on bodywork much more easily since they can control the conditions and state of the bare metal much more easily in the factory before applying multiple layers of rust protection below the paint.

16 hours ago, Clarkey said:

Doesn't sound too bad for the repair. I'm glad it worked out ok as I have a RC imx571 too. (Probably on your recommendation)🤣

Same here. I look in mine and see rust and during operation it sometimes stops and needs to be off-on cycled so I fear repair could be in its future... Or the crashes are purely software based...

3 hours ago, TiffsAndAstro said:

Bit late to the party but I remember making a cost list for a 1st year project 35 years ago at uni and the film and processing cost alone were more than £3k. Was shocked when I was told no chance, lol I am politely paraphrasing my tutor's response

 

 

The film cost was that high!?!? Was Kodak tech pan that dear or are we talking about some sort of scientific glass plate that's hypered, high speed but fine grain, and comes in sizes of 4x5 inches at the smallest and requires cooling and gases to store?

A normal colour roll of 35mm or 120 was quite affordable until only very recently when the costs rocketed up.

1 hour ago, Bugdozer said:

This is one thing that I am always curious about when people talk about really dark skies and the descriptions of them given in the Bortle classifications, because some of it doesn't quite make sense to me. 

Firstly, a higher Bortle sky is always going to have more light from the sky overall than a lower Bortle sky. No objects actually lose brightness under a high Bortle sky, they just lose contrast against the increasingly bright background glow that is everywhere, until at some point they are effectively rendered invisible. But their light IS still coming down. 

However, in my experience, once you get down to about Bortle 2.5, there isn't actually enough light to see any shadows at all. The Milky Way could be right overhead, and clear to look at, but I can't distinguish between looking at the ground and having my eyes shut. Basically, the amount of light given off by things like the Milky Way is below the threshold at which my eyes can detect reflected light from objects. I can believe something like Venus could give off enough light to cast a shadow at its brightest, but if I already can't see the ground at all, then having an even darker sky is not going to make shadows on it more visible. Seeing it reflected off water makes sense, but I am dubious of darker skies seeming to make our eyes more sensitive to light which is already below detection threshold.

The sky at my home has an Exposure Value (EV) of about -5.5 or so, and it's already dark enough that the ground is very hard to see even once I'm adjusted.

However a place near me is much darker, dark enough to see the MW core and even sometimes the outer spirals, which means it's probably closer to EV-7 or even EV-8, I can see the ground at this level but not clearly. I would guess if it were just the MW core in the sky and no sky glow at all, I'd struggle to see any ground at all as you say. The milky way just isn't that bright!

3 hours ago, tomato said:

Got an update from Eddie, the damaged PCB is now with the manufacturer (Touptek) for repair. He told me not to worry but I can't see me getting it back before astro darkness disappears, but then we probably won't get a break in the clouds either, so what's the rush?

It may be different up north where you are, but in devon I can manage about 1.5-2 hours of imaging during the astro dark holiday if weather permits, and with narrowband imaging I can get away with a bit more.

The brightest sky I see from that period here is when the moon is out, which means a moonless night in that time window is still better than normal full moon conditions, under which I'd either image a target at opposite sides of the sky to the moon, or use narrowband, and my results are usually somewhat decent as the last few years the summer period has had a good number of clear nights so I can make one target a multi-night project (relative to UK average...)

13 minutes ago, symmetal said:

I would wait until you see what results you get with your Canon lens with your current camera as far as corner star shapes are concerned before buying a full frame sensor. It wasn't until I bought the RASA 11 that I could take full frame images with the 6200MM with good overall star shapes.

My Canon 'L' 100-400 zoom gave poor star shapes over the whole frame unless I stopped it down to f8 when it was tolerable. A prime lens should be significantly better than a zoom of course, so hope yours performs well.

I tend to software bin my 6200 images after stacking, as the full size images can be a bit slow to process, especially if doing a mosaic.

2x2 software binning gives 2x the noise and 4x the signal, so a 2:1 improvement in S/N. Noise adds by using the square root, so with a read noise of say 2e, the 2x2 binned read noise is sqrt( 4 * (2^2))  = 4e. 🙂

Alan

Wait noise adds with the square root?? How does this work?

I want to improve the speed of my setup. I worked out that if shooting only RGB then the ASI 2400MC would afford me effectively the same resolution image as my RisingCam 571 (6000x4000) but with a wider FOV due to the larger pixels, since I am speeding up my imaging with a normal camera lens I expect that would be best for star shapes anyway, while affording me a 1 stop boost to my speed (so 6.2x faster than my RisingCam+ f5 scope)

However it means narrowband (My main interest turned out to be Halpha only really, not worried about the loss of SII and OIII) becomes much less efficient as only one subpixel gathers data for it.

If I got the ASI 6200MM I can keep my narrowband capacity but with the 3.76 micron pixel size, the same as my RisingCam, I won't gain the speed increase as I would with the 2400MC.

Unless, I binned. A 3200x4800 image might be a little small for me but could be servicable. However this increases the effective read noise by a factor of four even though in theory is gives me a 2 stop light sampling boost right? So am I worse off with the 6200MM and should stick to RGB imaging with the 2400MC if I want speed, and simply forgoe narrowband for now?

Interested to hear thoughts.

Thanks

7 minutes ago, vlaiv said:

I don't know much about this, but from what I've gathered, rated voltage of stepper is not important as it is used. This I've gathered from 3d printing forums as steppers are used to move the mechanics of 3d printers.

In any case, stepper can be driven in two different ways, if I'm not mistaken, and most modern stepper drivers are current drivers. They just pump enough current (depending on settings) to get the motor running. I think that max voltage has something to do with holding torque in that case - if you want more holding torque (or is it max speed?) - you need to provide higher voltage. Some stepper drivers work with 48V - and you can use those drivers with 3.5V motors for example.

With current drivers - you really don't care about declared voltage.

See this answer for more details:

https://electronics.stackexchange.com/questions/200324/how-to-interpret-the-stepper-motor-voltage-requirement

I only have a cursory knowledge of electrics in motors in general, but I think as a motor spins faster the magnetic back force increases which means you need yet higher voltage to move the motor. I'd guess if voltage correlates to max speed it's because of that. Holding torque I'd guess would be current based as the strength of the magnetic field is proportional to current and not voltage.

21 hours ago, wimvb said:

Btw, does anyone know if this is a 0.9 or a 1.8 degrees/step motor?

The number of bars on the rotor shows you the step angle. A 1.8 degree motor will have 100 bars on the stator and 98(IIRC) on the rotor. A 0.9 deg motor will have twice as many.

Yours certainly looks like an 1.8 to me

I bought one of these and it seems to be quite good

Of course it will be most effective once the sun goes down. You can position it some distance away while your camera is on a tripod, focus on it and the picture will show you the sharpness you can expect from stars. Just adjust the camera's orientation to position the fake star at different parts of the frame: https://www.firstlightoptics.com/other-collimation-tools/hubble-optics-5-star-artificial-star.html

For smaller camera lenses (nifty fifties?) I'd guess the larger holes will be suitable and nice and bright once more than 10m away. For bigger lenses ideally you want as much distance as possible. Most lenses will decrease in quality as you focus closer.

10 minutes ago, Bugdozer said:

I believe not every Canon lens is even possible to fit with an adaptor, due to Canon's "innovation" of making the auto focus motor part of the lens rather than part of the camera body with some models. I don't know whether that applies to this particular lens.

This lens does have a built in motor, and given it was designed in 1987 that's definitely way ahead of its time as Nikon would use the in-camera motor until I think the 2000s. I suspect the need for the motor to be insanely fast to track sports and wildlife led to this design choice. The lens from reviews I've seen almost literally snaps into position on subjects, and this lens is big, so moving it (and quickly too) would put a lot of strain on a wimpy in-camera motor I think.

Regardless, all manufacturers use in-lens motors now and only pro tier nikon DSLRs have the built in motor for legacy lens support (Nikon D850, D7500 and similar). The bit that irks me is not being able to manually focus the lens AT ALL without it being powered. But then the lens wasn't designed for people who would care about that I assume...

7 minutes ago, symmetal said:

Hope the one you're buying from Russia works out for you @pipnina. In your first post you said the lens was non IS and non USM, though it does say Ultrasonic on the label implying it's USM focusing. Did you get it cheap because the USM isn't working? How will yours focus if that's the case?

As they are quite inexpensive I've bought a set of these EF extenders to make it easy to get to the lens connections and have a go at interfacing with an arduino. I programmed my current arduino based autofocusers to use the Moonlite autofocus driver, to avoid having to write a separate Ascom driver, so it should be fairly easy to adapt it to create EF protocols I would think. 🙂

An official Canon extender is £170 for one, but these are £38 for all three so no great loss if I ruin one of them. It'll mean drilling a hole in the side of one of them to solder wires to the rear of one set of contacts.

 

Alan

 

Ah yes you're right there is only the original lens (the one I got, from 1987 https://global.canon/en/c-museum/product/ef270.html)

Which is not IS but does have the ultrasonic motor. Then the subsequent 2 versions are simply IS USM and IS USM II.

I just re-checked the ebay listing and they don't mention broken motors. I suspect I got it uncontested because of the very minor damage to the front element (two small chips, noticable but I suspect not ruinous to the image, won't know for sure until I can test it though!)

I still have my fingers crossed (now that I've been re-injected with hope due to this adapter) that it'll prove a very suitable replacement for my telescope.

On 14/03/2024 at 05:54, wxsatuser said:

There is

Astromechanics Ascom Canon lens controller.

May be hard to get one as they are Russian and importing might be hard.

Plus not cheap.

Be aware although a very nice lens old versions may have issues with CA etc.
You may get a good one or not.

On 14/03/2024 at 09:25, Adam J said:

One of these adaptors from Astromechanics would solve your problem. 

Astromechanics

You might be able to find one that is in someones old stock, I know FLO used to sell them. Apart from that it may be a problem importing. 

Maybe a wanted notice in the forum and on Astrobuysell uk. 

Adam 

 

Sergey from Astromechanics replied to me earlier, managed to work out a way for me to pay and that the UK does not impose the same restrictions as the EU so they can deliver it to me directly. They suggested 12-20 days on average until it should arrive, I await it patiently and thank you guys for letting me know of its existence!

Feels a bit wrong to buy from russia at this time but alas it seems they are the only ones who have made the exact part I need.

8 hours ago, wxsatuser said:

There is

Astromechanics Ascom Canon lens controller.

May be hard to get one as they are Russian and importing might be hard.

Plus not cheap.

Be aware although a very nice lens old versions may have issues with CA etc.
You may get a good one or not.

4 hours ago, Adam J said:

One of these adaptors from Astromechanics would solve your problem. 

Astromechanics

You might be able to find one that is in someones old stock, I know FLO used to sell them. Apart from that it may be a problem importing. 

Maybe a wanted notice in the forum and on Astrobuysell uk. 

Adam 

 

My goodness! If I can get my hands on one of those it'd be just the ticket! It would solve the challenge of autofocusing as well which requires some jury rigging on manual focus lenses.

I've sent them an email as their website seems to suggest the UK doesn't impose the same level of sanctions as the EU... I await their response.

I'll hold onto the lens for a bit to see if I can get hold of the adapter. If I can it might just push me over the edge to buying an asi full frame camera haha. It's been my plan to downsize from my big scope to something faster and more portable so if this lens and adapter work... I'll be over the moon!

Thanks for the links both of you!

I thought I scored a real deal when I won the bid for a Canon 300mm f2.8 L (non is non usm) for only £600. Given the lens was originally over 4000 I felt pretty good about it.

Until I got my hands on it today. And learned that it WILL NOT manually focus and cannot be focused AT ALL unless a canon DSLR is attached to it. So it may as well be a brick as far as my astrocam is concerned!

I am beyond disappointed and to make matters worse, my normal DSLR is a Nikon so I can't even use it on that. I guess I can only hope that I can return the lens to the ebay seller and find another set of optics to try for compact and fast astro imaging unless anyone knows a way to hack it lol

Captured back in January on my 130mm f5 triplet.

Forgot to post here at the time but quite pleased with the result- just wish I got another night or two to add data to it.

I have tried to do astro with my Pixel 6 in a similar way with the same app. I also ran into the same flat calibration issue.

I suspect the lens suffers too greatly from internal reflections. I also noted that despite the images supposedly being RAW, it appeared as though the camera was still imparting a white balance into the image which may affect matters.

I also struggled a LOT with hot pixels. Did you succeed at removing or handling them in your phone? In my case I was shooting in summer so it was 15c outside.

I also did not have BlurX or NoiseX. Certainly however many differences in technique (or hardware from P6 to P7) your result is miles ahead of what I achieved!

1 hour ago, Ratlet said:

I did a quick google to check that statement.  Honestly I think it already does!

https://hubblesite.org/contents/media/images/2006/14/1876-Image.html

If it weren't for the diffraction spikes I think you'd struggle to tell them apart.

I think Alan has created a more pleasing level of contrast and balance of colour than the photo editors of the hubble project. However one cannot deny how impossibly detailed and sharp the hubble image is (and always will be) in comparison to our meak sub-meter telescopes!

Hubble images often have an almost greeny tint to them and sometimes squander the red colours. Alan has captured a beautiful blue hue in the galaxy with maybe a slight magenta lean and has produced incredibly vibrantly scarlet hydrogen.

That's my take at least.

I think if this image were any better it might make Hubble blush!