AnonymousAnimosity

23 hours ago, alacant said:

Hi

Assuming you have the guide camera connected (via whatever-your- guidecamera is called) in the guide module and dither pulses are indeed being received by the mount...

To lose the walking noise, you need to move the camera in declination as well.

To optimise RA at 135mm, set the maximum dither in EKOS  (currently 10) and delay the start of each frame in capture by say 10s to allow the rig to settle. Whilst you're in capture, set something reasonable for the guiding settle distance. 1.5 px works ok for us.

Stack using a clipping algorithm. sigma 5, 2 or windsored 3,3 work well with our 700d, but YMMV.

Cheers and HTH

 

Thank you, since there is only one parameter to be set for ungided dithering in EKOS I will get back to this and try the settings you suggest when I find the time to sort out guiding.

7 hours ago, michael8554 said:

The image scale is 6.55"/pixel 

To dither the 100D by the commonly used 12 pixels, the mount needs to move 12 x 6.55 = 78.6 arcsecs.

So does a pulse of 0.5ms, or 10, achieve that ?

Michael

 

My bad, I mean to write 0.5s! Although I must have read somewhere that a few pixels were enough I will definitely increase the pulse duration and aim for 12 for the next attempt. Thank you for pointing out the mistake.

A few nights ago I tried doing unguided dithering of the skywatcher star adventurer through EKOS. The tracker is connected via the ST4 port to a guide camera (which I've yet to use) that is controlled by EKOS. I left the pulse duration at the default value (0.5s), which should be enough to dither for enough pixels at 6.55"/pixel (samyang 135 and canon 100D).  Stacking was done in SiriL. 

I shot about 120x120" lights, calibrated with 15 flats and biases and this is what the background looks like:

there are still visible patterns but it's a bit better compared to what I usually get.

The following night I took about 100x180" lights, calibrated with flats and biases:

Yesterday I further increased the dither pulse duration in EKOS (0.8s if I'm not mistaken), this time double the amount of subs:

I am not sure what I should do differently to solve this problem. Any ideas?

3 minutes ago, teoria_del_big_bang said:

Ah, its the polar alignment part of the module you need - ah I understand now and yes that makes sense.

Does THIS tutorial help at all ?

Good luck with it all, I am sure it will all become clear to you soon 🙂 

Steve

That is indeed very helpful, thank you!  

I don't have much time to dedicate to astrophotography so for the time being dithering and polar alignment are the only uses I'm looking ot get out of astroberry, I will look into guiding in the future.

5 minutes ago, teoria_del_big_bang said:

I still am not sure what the Align module would do for you as it cannot align the mount. Maybe it can tell you the error so you can manually adjust it to account for any error ?

Yes that's what I'm hoping for! In normal conditions polar alignment is pretty quick, but if this method worked it would be useful when polaris is not visible.

3 minutes ago, teoria_del_big_bang said:

Sorry but I have no experience with the SW Star Adventurer tracker but are you saying that there is no port on them that connects to a computer ?
How do you send it to a target then ?

In Ekos I see there is a driver for this mount so I am a bit confused.

Steve

It's not a GOTO mount, just a tracker with a motorized RA axis, so targets are aimed at manually. There is an ST4 port for autoguding and a usb port but I've read that it's not for connection to a PC.

I noticed there is a driver in EKOS but I couldn't connect to it so that's confusing.

1 minute ago, teoria_del_big_bang said:

Ah, I think I have missed one of your comments here in that you say the mount (or tracker) cannot be connected to RPi.
If that is the case then the Align module will not enable because it cannot do anything.

The Align module is used to send the mount to its target and if you have the plate solving software installed basically takes a short exposure and plate solves it to see if there is an error and the mount is not pointing at the target and will then correct this error.

BUT, if EKOS is not connected to the mount it cannot do any of this because it has no control over the mount.

Steve

According to information found on the INDI forums it seems that the only way to get it working is to select "telescope simulator" as a mount, that does in fact "unlock" the align module. I will read up some more and test this on the first clear night. Thank you for pointing me in the right direction! 

22 minutes ago, teoria_del_big_bang said:

It sounds like either the main CCD camera or the mount is not recognized by EKOS.

Can you put up some screen shots of all your tabs in EKOS as a start then we may be able to see what is missing and point us in the right direction (not intended as a pun but quite funny).

You talk a lot about getting a guidescope and guide camera, normally this has nothing to do with the align module, unless you are trying to align via your guidecam and guidescope instead of main scope and main camera.

Steve

Both cameras seem to work properly, at least I can capture preview images. My tracker can't be connected directly to the raspberry so I figured I had to use the ST4 port of the guide camera.

Here are the screenshots:

edit: I have just now noticed that I'm supposed to have a mount in the EKOS profile, however it doesn't look like the star adventurer is recognized through either ST4 or usb (I guess it's just for power).

Yesterday I finally had the time for a quick imaging session after a few months of non-stop studying, just 30 minutes around Deneb at f2.4 I believe. No colour because I like the contrast better this way.

Hello, a few months ago I bought a cheap guidescope, a T7M guide camera and a raspberry pi 4 to perform polar alignment, dithering and eventually guiding on the skywatcher star adventurer.  I have read the documentation for the "align" module, however I can't seem to get it working, all the buttons in the "align" tab of EKOS are greyed out. Has this happened to anybody else? If you use a similar setup with astroberry and a tracker I would be thankful if you shared your experience.

18 minutes ago, Adreneline said:

Very good star colours.

Thank you! I used Startools for processing. 

A quick picture of the Beehive Cluster.

My first two pictures with this lens, Star adventurer and modded canon 100D. Stacked in Siril and quickly processed with StarTools.

72x120" lights at f2, calibrated with flats and biases

91x120" lights at f2.8 with l-enhance filter, calibrated with flats, biases and darks. Dark optimization in siril does seem to reduce pattern noise a bit.

18 minutes ago, Richie092 said:

I suppose it depends on what is going on top of the ring. If you are mounting a guide camera on it then it probably won't be worth it. If it is staying as it is then it will only need a tiny bit taken off, personally I would file it.

I would like to mount on this 30mm guidescope, it looks like it should fit even if I file the rear of the base.

Today I finally picked up the WO redcat ring, sadly it clashes with my camera so rotation is impossible. I am not sure whether I should try to file it or just return it and buy something else.

I've been using a star adventurer with camera lenses for some time and I was contemplating the same decision recently, I can offer a few comments on the scopes you have linked based on my limited knowledge.

• You will need a field flattener (more or less specific for each scope) unless you buy one that already comes with it, such as the TS Optics EDPH 61/274, so budget that in as well
• I have seen some good results from people shooting at focal lenghts over 300mm on a star adventurer, but keep in mind that your polar alignment will have to be spot on every time, the lengths of your subexposure will be limited without autoguiding and you will probably have to discard a significant portion of your frames due to wind and periodic error. I think that using an 80mm refractor could get very frustrating.
• A good knowledge of the night sky (aided by software like Stellarium) is necessary to frame targets manually, you may want to look into platesolving solutions to make life easier

I ended up buying the Samyang 135mm f2 lens rather than a telescope because pretty much every refractor I considered in the €800 range didn't strike me as of particularly great value for the money (if you are patient and wait for good second hand deals that's a different story). 

The cheapest option for a telescope might be the Skywatcher Evostar 72ED, you can buy it new with a flattener for about €500 but (based on what I read) I'm not sure I would recommend it without autoguiding (€200 or so for a cheap guidescope and camera). 

3 hours ago, Space Oddities said:

ASI120 or similar works very well for that setup! I use it to guide my Samyang and my RedCat with the same guide scope and that's more than enough

 

Thank you, since the Redcat ring is out of stock for a while I am looking for some alternatives. Mounting the guidescope to the support ring of the lens seems like the easiest way, but I'm struggling to find telescope rings of the right size, I can only find smooth ones (no holes to screw in a finder shoe). Perhaps drilling a couple of holes in these? I'm not sold on 3D printed PLA ones like astrokraken or astrojolo/

Do you know of any alternatives?

I have just purchased this lens, I intend to use it with a Canon 100D on a Star adventurer (might swap it for an Az-GTI for mosaic automation). 

To mount the lens I will buy the William Optics Redcat ring and a short dovetail. 

https://www.firstlightoptics.com/william-optics/william-optics-redcat-spacecat-single-mounting-ring-black.html

What is the best option for a guidescope? If I'm not mistaken this 32mm guide scope from FLO should be appropriate for my image scale.

https://www.firstlightoptics.com/guide-cameras/astro-essentials-32mm-f4-mini-guide-scope.html

 Is it necessary to also buy the Redcat handle bar (https://www.firstlightoptics.com/dovetails-saddles-clamps/william-optics-cat-series-saddle-handle-bar.html) or can this be attached directly to the top of the mounting ring?

As for the guide camera an ASI120MM should be enough right?

On 24/12/2020 at 01:19, rickwayne said:

You can quantitatively analyze your images to see what might be most economically improved.

It also pays to be aware of your image scale -- how much  of the sky is represented by each pixel. My K5-iis DSLR, for example,  is somewhat  undersampled  for my Stellarvue, meaning that the pixels  are a little too big for optimal  detail. That's one reason I selected the ASI183, which has much smaller pixels. Good primer and calculator for that here.

For now a raspberry pi running astroberry seems like a cheap solution to many problems, it should help with consistent focusing, faster framing and dithering to get rid of walking noise. I thought that stacking lights from multiple nights with slightly different framing would be akin to dithering but it doesn't seem to solve the problem.

On 24/12/2020 at 01:19, rickwayne said:

It also pays to be aware of your image scale -- how much  of the sky is represented by each pixel. My K5-iis DSLR, for example,  is somewhat  undersampled  for my Stellarvue, meaning that the pixels  are a little too big for optimal  detail. That's one reason I selected the ASI183, which has much smaller pixels. Good primer and calculator for that here.

Undersampling seems unavoidable with a DSLR and the focal lengths I'm imaging at. But I will keep it in mind if I decide to upgrade the camera.

6 hours ago, rickwayne said:

What dissatisfies you with what you're producing now? That would inform any practice, gear, or software recommendations I could make. Trailed stars e.g. leads to different advice than noisy images.

I would like to take pictures of better quality where the background is smooth and fine detail is well defined when zooming in, something that would look good as a wallpaper or maybe even printed. I am aware that processing is absolutely key, but I don't think I can acquire data that is  sufficiently clean and sharp to get the sort of results I have in mind. 

Another concern is maximising the opportunities to shoot, the amount of data I can gather (faster optics basically?) and the number of targets that I can frame up nicely (longer focal length?). 

I apologise in advance for the long post!

Hello, I would appreciate some advice and perspective on finding the most cost-efficient way of optimizing my current astrophotography setup. I am in no hurry to upgrade as I have yet to push my current equipment to its limits, but I feel like I need a sort of long-term plan and sense of direction to keep myself from getting the "shiny new object syndrome" and compulsively browsing FLO whenever I see nice pictures.

My first year of astrophotography was with an unmodified pentax K-S1, a tripod, a 50mm lens and very cold hands since the camera did not support a wired intervalometer. With that equipment I was able to capture the M81 and M82, the orion region and andromeda. Buying a skywatcher star adventurer was a massive upgrade, together with a 200mm lens it opened the way for galaxies like M101 and closer views of the pleiades, orion and andromeda.

A few months ago I bought a modified Canon 100D, an intervalometer (finally), a vintage 135mm lens (which suffers from less aberrations than the aforementioned 200mm) and an optolong l-enhance. This has allowed me to shoot targets such as the California, Heart and Soul nebulae even from urban skies (bortle 6) with a full moon. I am sitting on a few nights' worth of unprocessed data because processing is time consuming and studying takes up most of my time. I purchased a Startools license so I think I'm covered from that point of view, even though I plan on checking out the free trials of Pixinsight and APP once I acquire more (and better) data.

I find myself unsatisfied with the results I can produce and lately I've done a lot of research into the manifold possible paths of improvement.  I am set on sticking with the star adventurer as it allows me to set up very quickly and it fits nicely in my backpack when visiting darker skies. I have no plans to purchase a full-on equatorial mount as I wouldn't be able to carry it back and forth. Here are some key points I have noted down:

• A faster and sharper lens such as the Samyang 135 f/2 would allow me to acquire better data much faster, but I feel it would be a temporary band-aid as there are many targets which are rather small at this focal length therefore
• A long telephoto or a short telescope would enable me to get more details out of big targets and allow me to image smaller nebulae, however guiding would very likely be required (about 500-800€ for the telescope and €250 for guiding)
• Selling my current equipment and buying a used mono camera + some filters would be expensive (I believe no less than €800 more than what I could make reselling some items and possibly a kidney), but I am very fascinated with the aesthetics of SHO pictures and it seems suited to a 135mm lens. Is a star adventurer even precise enough for narrowband imaging (considering the need for longer subs)? I suppose guiding would be a mandatory requirement.
• This one is probably a bit gimmicky: selling my current camera and buying an ASI533MC + Evoguide 50 with a flattener, the difference would be similar to the price of a Redcat but I would get the added bonus of cooling I guess? Not convinced about this one.
• I own another DSLR for daytime photography so in theory I could go frankenstein on the canon to try and cool it or debayer it, but I am not sure I'm willing to accept the risk of messing up and rendering it useless.

I thank you in advance if you've had the patience to read through the whole post, I would be grateful for any input and opinions concerning the points I have brought up or your own experience with this hobby.

On 14/12/2020 at 21:21, alacant said:

Perhaps you mean the lens was set on A? 

That is what I meant yes.

On 14/12/2020 at 23:02, alacant said:

@AnonymousAnimosity I wonder if we have the same lens? On our example, the blue and green coincide almost perfectly. Maybe it's the filter... Dunno.

I do believe we have the same lens judging by your picture. In the previous post the images of the three channels were in the wrong order, the out of focus one is red, so green and blue are very close.

The filter definitely alters the focus across the 3 channels a bit, these are excerpts  (R, G, B.) from a picture that was taken without.

12 hours ago, alacant said:

II's nice. It doesn't give the usual undersampled looks-like-it's-been-taken-with-a-cheap-lens type images; better than my Takumar 135. Focus is however super critical as outlined below.

Apart from being painfully slow at getting the light captured, one annoying point is that the diaphragm blades have a sharp notch-indentation at each corner which produce spikes even on dim stars. Gonna try some step down filter rings instead. Focus against the lens stop gives red star halos with true infinity being around 1/10 of a turn away. The best way we found was to centre say, Capella and focus away from the lens stop until the red halo just disappeared. Focusing with a Bahtinov yields red halos, so not much use with this -and many other- old lenses.

 

 

I have been using this lens for a couple of months and I've never managed to focus properly with liveview, maybe it would be easier with the camera connected to a PC. Yesterday I tried making a quick Y mask and realized that as you pointed out when the spike is centered the red channel is actually way out of focus leading to red halos around the stars. Maybe it would be helpful to still use the mask balancing the spike's position in the 3 separate channels?

This is a comparison of the 3 channels of a quick picture from last night taken with a modified canon 100D and a clip in l-enhance filter. I set the aperture ring to around f/5.6 but I did not notice the camera was on A mode, so the lens was wide open.

Here's a picture of the Sadr region at 135mm (Carl Zeiss Jena 135mm f3.5 at f4) with a modded canon 100D and the Optolong L-Enhance clip-in filter. 74x180" lights at ISO 800 plus flats and biases. Stacked in DSS and processed in startools, perhaps too aggressively. It was taken from a bortle 6 town a few days ago when the moon was almost full.

11 hours ago, AstroFin said:

Hi!

I live in Finland, so I can relate. You’re probably going to need at least a spare battery or a “dummy battery” for your DSLR. In general, it is always important to have a good ( =reliable) power supply while imaging in low temperatures. A dew geater band for your camera lens/telescope is also essential. Otherwise the lens will freeze.

If you want to image at, let’s say below -10°C, it would be smart to change the stock grease of your tracking mount to something of higher quality. I know people who use aerospace-grade grease on their mounts.

Pay attention to the focus, as the temperature drops, sometimes quite drastically, you might need to refocus during your session.

It’s worth noting that the screen on most GoTo mounts will stop working when the temperature drops below around -10°C. The hand controllers were unfortunately designed for the conditions of California, not Scandinavia. The controller itself does work, but you can’t read anything on the display. You can build a heater or try using a dew heater band on the screen.

There are some upsides, though. Your DSLR sensor will be cooled down and image noise will be reduced! Also, the nights are very long, so there is a lot of time to take images. 

Oh, and don’t forget to shoot the auroras! I had a great night imaging them last Saturday.

I’ve done visual Lunar observing at -30°C, but only once. The weakest part of my observing kit was the observer itself, since I was the first to give up...  😅  Moral of the story: remember to keep yourself warm! 

 

What kind of power supply would you suggest for powering a DSLR in low temperatures (0 Celsius and below)?

4 hours ago, Whistlin Bob said:

I find that we're always our own harshest critics, so I can understand you may not be entirely happy, but I think that's an absolutely terrific image.

The focus and framing seem bang on and I can pick out lots of my favourite targets for a summer nights observing, not least the veil and the crescent. I love the density of the stars through most of the image, how prominent the dark lanes are and the bokeh on the brightest stars.

Perhaps a touch more saturation would be good, but I wouldn't change much.

Looks like the nifty fifty has struck again!

Thank you, it's easy to lose perspective of the quality of the images I capture when compared to more expensive setups. That said, I'm sure I can optimize both acquisition and processing far better.