AstroLearnerWill

I found it quite interesting that on one of the frames I captured, I see a strange light next to the galaxy, that appears to match the shape of the galaxy. It's the only frame out of 200+ that has this. 
What do you think caused it? 

You can see it here in a screen recording I captured of the raw image with the strange light while switching to and from another raw image that doesn't have the light showing:

edit: most likely a cosmic ray!

Hey

Fairly pleased with how M51 came out last night. Very clear skies and mostly a straightforward imaging session minus the telescope hitting the mount 6 minutes before I was due to meridian flip (whoops) - I've updated the meridian flip settings in NINA to account for this now. 

As always, I'm keen to hear folks thoughts and especially where any improvements can be made. I do consider myself a rookie with this hobby still! 

141x 60sec lights
75x bias
75x flats

Using NINA, PHD2 for capturing. 

Siril for stacking, pre-process, background extraction and photometric colour calibration. 

Photoshop for various actions from Annies Astrotools, including stretching and finer adjustments. 

Needless to say I will be purchasing an assortment of REAL fuses! Thanks all for the help.. and what an interesting 'edge-case' you come across in the hobby. 

On 28/02/2023 at 20:45, Carbon Brush said:

While thinking about using mains on astro kit.......

Many items (originating in China) have a 13A fuse in the plug. A one size fits all solution. A bit like chicken wire  in a home fuse board🤔.
Always when you buy a lead or equipment check the fuse.
For example ,small items (like the clone Canon coupler) take very little power. Use a 3A or lower fuse.
Always rate the fuse according to the equipment.
A lower value fuse will ensure events like the OP cable failure have a quieter BANG!

Another problem I have seen on some Chinese equipment is fake fuses. Yes FAKE!
The fuse used in our 13A plugs is 1" long.
The fuse wire is NOT taken beyond the ceramic tube and bent over. It is internally fixed.
Those above are two giveaways I have seen on fake fuses.

Another one that you don't see unless you break open the fuse is the filling.
A properly made fuse contains a fine sand to quench the arc when there is a big fault to vapourise the wire - yes it happens.
I have seen fake fuses without the sand, which means the energy transferred under fault is far higher.

When I challenged the equipment manufacturers, they tried to fob me off with what are best described as fairy stories.
As the parts had come from amazon, that was where I went next. amazon withdrew the items from sale.
Though probably a less than scrupulous marketplace seller remarketed a week later under a new name.

Needless to say, anything not bought from a big name with known quality controls is best treated with suspicion.
The amazon marketplace and ebay sellers...........

If in doubt, swap the fuse. A known good fuse purchased from an assured source costs pennies.

HTH, David.
 

Thanks @Carbon Brush

Out of interest I broke open the fuse of the offending plug to see what was inside, what do you make of this? Certainly no fine sand, for one. 
 

5 hours ago, ollypenrice said:

Beware of buffoons on U-tube! It is full of people heaving this way and that on an assortment of sliders till they 'get something they like.'   Look out for Adam Block and Warren Keller, who can be relied upon.

Olly

 

Thanks for the recommendations!

22 hours ago, ollypenrice said:

that learning the ropes of a stretch tailored to just the one image in question is the key thing

Agree - I do struggle with understanding how and what this is, and it ends up being a bit of a lottery how it turns out.
I've got the basics of what a histogram is but need to find some tutorials / videos on proper stretching / transformation / that side of things

Ah yes it could possible be related to the cold as it was near 0 celcius when it happened. 

Also, it was definitely a cheap cable that came with the cheap coupler, from Amazon. 

How would one go about avoiding mains on the scope? Say I've got a pegasus advance box on the scope, that reduces all the mains cables to just one, ie the cable powering the advance box. This is a cable / power supply from pegasus so I'd hope that would give a bit more durability. But is even just one cable attached in that fashion avoidable? 

Thanks

3 minutes ago, Elbasso said:

If only myself tripping over the cables in the night

Yep, did this too

They're definitely too expensive! As is the norm for this hobby unfortunately..

Nearly everything I've bought for my setup including the pegasus has been second hand from https://astrobuysell.com/uk/, which helps a little. Then you have the expense of all the short cables you need to do it neatly. Still, I'm hoping that it will reduce my setup time somewhat. 

As a relative newbie, my approach to the hobby has been to:

1) take some images

2) realise where an improvement can be made (there are always improvements or something new to do)

3) make the changes / spend money / optimise

4) rinse and repeat

I went through such a journey this week and learned why you shouldn't have six cables all sporadically sprawled across an active mount & telescope (HEQ5 + SW 80EM).

(I have three 5m data cables heading to my laptop, three power cables, plus dew heater cables)

A loud bang and a bright flash later I find that the power cable to my Canon coupler had completely blown off.. 

Needless to say, I have a Pegasus power box advance on order..

14 hours ago, LuckieEddie said:

Nice.

For any given amount of time on a target, I'd suggest taking significantly more exposures, even if they have to be shorter. 10's or even better 100's of subs will let the stacking average out the noise, including satellite trials. For the same reason 10's of darks are recommended.

Gotcha. I was thinking I might take some more lights when I get a chance in the upcoming weeks, and also some darks (though the jury seems to be out regarding if they're useful for DSLRs with the temp fluctuations), and then compare the images. 

On a separate note, I would love to learn more about post processing, someone with a lot of experience should do an online course on it, I would certainly pay for that! For now though I guess we have tutorials and youtube videos. But it's a tricky one to know where to start for beginners.  

Posting only the third image I've captured and processed after building an astrophotography rig. 

Any thoughts / guidance is appreciated and welcome, you only get better by listening to what other more experienced folk have to say. 

I'm using the updated version of Siril (1.2), and trying the new generalised hyperbolic stretch tool. My peak ended up being left of the 25% mark so I don't think I did that well. 

You can also see a satellite artefact in the image which isn't great. 

Overall I think there is a ton of detail in my images, which I'm pleased with and I'm sure can do better with it, but the contrast isn't great and the sky isn't very 'dark' in the image. I'm bortle 5 and this was taken on the 26th Feb 23. 

Thanks

Equipment:

HEQ5 Pro, skywatcher 80ed, 0.85 flattener, modified D600, guidecam, l-enhance filter.

Images:

18 x 9minute subs + biases + flats + only 2 darks.

Processing:

All in Siril 1.2.0. Preprocessing + manual selection of stacking images. 

* Photometric CC, Background extraction, generalised hyperbolic stretch. 

Thanks all, again, that makes perfect sense re PA now.

Thats cleared things up. I've also marked the mount where 'home' is using the video linked above. I'll set the mount to this position at the beginning of every session to make things a bit easier.

Thanks all for the help, very insightful.

I'll be adding a step to do a manual platesolve and ensure the 'sync' setting is 'On' in Nina. This will ensure the mount knows where it is. I presume the automatic platesolving as part of 'skew and center' in the framing tab does not sync to the mount.

I'm a bit confused why I don't need to polar align necessarily. My understanding is that this is important to reduce any field rotation in long exposure images and to give the guider higher accuracy and therefore better sharper images.

Hi

My current startup routine looks something like this. 

Balance scope and mount

put heq5 pro roughly in home position and switch on

nina 3 point polar alignment to get roughly in the right place 

nina 3 point polar alignment to get more accurate 

Slew and center on a bright star so I can manually focus with a mask. 

Slew and center on target, start guiding, begin imaging. 

The thing is, every time I slew and center the mount is never very close to where the target is on its first attempt and usually goes through 3 or 4 re-slews and plate solves to get it right. 

Should I be doing some kind of goto alignment or home calibration so the mount knows where it is? Presumably it’s solely relying on the best guess home position I start it up in, at the very beginning of my process. 

Also, I’ve previously had the mount unable to move on occasion stating horizon limit, despite not being close to it, which makes me even more curious about the goto alignment.

Thanks for any advice! 

2 hours ago, Fegato said:

I'm guessing you're around F/6.5 with your setup?

That's right. I do get fairly good guiding with my setup so I can afford to increase the exposure time (clear sky time permitting). I'll give that a go and get some more detail. I landed on 164s subs after using Nina's optimal exposure calculator, plugging in data from a sensor analysis with Sharpcam.

13 hours ago, Rallemikken said:

What filter did you use?

L-enhance. First time using this filter. I'm in bortle class 5 skies and on the day had a 100% full-moon very close to where I was pointing the telescope (brilliant timing with the clear skies). I used the l-enhance because I wanted to isolate the Ha which as others have mentioned is strong in this nebula. So perhaps I can expect a stronger red detail due to that choice. On another night with no full-moon and darker skies, I'd like to try without a filter and see the difference with this nebula.


Thanks everyone for your feedback, I am amazed and grateful for the constructive critical feedback. Really is the only way one can improve.

I've got some new post-processing techniques to try and also probably the biggest factor is to get more data as mentioned by some of you above. Ideally on a night without a full-moon close-by. Due to being impatient and lack of clear-skies I've tried to get everything done in one evening, I should consider multiple evenings or leaving the scope out capturing images overnight.
 

10 hours ago, Rallemikken said:

Siril and Gimp are all you need, but it takes time to master both. And don't rely to much on tutorials, try to find a workflow that suits you and get the most out of your data. In this case it looks like your color balance is way out.

As a start, you need a good fits-file. I have added a script to Siril, and runs it in semi-automatic mode. See attached file. Prepare stack as usually, after it finish run "cd process" on the command line and "Search sequences" under the sequence tab. Choose the last one, r_pp_light_.seq, and head over to the "Plot" tab. Learn how to exclude frames, and prepare the stack with only the best left. DO NOT be to eager to dump frames with high FWHM. When skies drift over the FWHM drops, but the signal gets worse. Many times I drop the frames with the lowest FWHM of this reason, the signal sits in the darkest frames. When it comes to roundness, be a little more brutal. Then the stacking tab: I mostly use Average stacking with rejection, Additive with scaling, Sigma Clipping 2.5 / 2.5  Once you have a fits-file, copy it out of the Process folder and start to play. Take a look at http://www.agle.no/astro/vis_enkeltbilde.php?indeksnummer=54  Pretty similar gear.

This is the exif of what I did in Siril, in this order:

Photometric CC
SCNR (type=0, amount=1.00, preserve=true)
Background extraction (Correction: Subtraction)
Median Filter (filter=5x5 px)
Asinh Transformation: (stretch=   8.0, bp=0.00000)
Asinh Transformation: (stretch=   7.0, bp=0.00000)
Asinh Transformation: (stretch=   6.0, bp=0.00000)
Asinh Transformation: (stretch=   5.0, bp=0.00000)
Asinh Transformation: (stretch=   4.0, bp=0.00000)
Asinh Transformation: (stretch=   3.0, bp=0.00000)

The SCNR is the "Remove green"-filter. The new background extraction in Siril has become really good, with preview and no loss in signal. Rest is done in Gimp. Play around in Siril with the same fits, and save different versions from this as tif's.  See what you can make the most of in Gimp. Every image has it's own quirks. Don't drift to much between different applications. They all do the same, it's just a matter of learning to master each one. There is nothing in Pixinsight or Photoshop that can't be done in Siril and Gimp. Just take your time, and DONT DELETE old datasets. In a year or two you will brush the dust of them, and present new images as you learn.

OSC_Preprocessing_no_stack.ssf 1.3 kB · 2 downloads

Hey

Thanks for your advice and feedback, that's exactly what will help me improve.

It's a good experience actuallly doing some of the stacking myself, I've learnt a few new things about the process.

I went through the process you mentioned step by step and came up with the attached after some minor editing in GIMP. What do you think? The colours appear to be a bit better balanced, not just full on deep red. A bit more of a spectrum of colours visible and some extra detail. Of course I'm only expectations minor improvements here, but as long as I'm heading in the right direction.

Thanks.

Hello, I'm a beginner and have been following some tutorials on pre and post-processing, but I'm sure I can do better with this nebula!

I managed to get some clear skies last night and took around 30x160s lights and the same biases, flats, and darks. Using an 80mm SW refractor, HEQ5 Pro, flattener, 600d astromodified. I'm using an l-enhance filter for the first time too.

I've used siril and this guide to both pre-process all of the frames into one image, and then some basic post-processing as mentioned in the tutorial. Which produced the image attached to this post.

After pre-processing and photometric colour calibration, I see a lot of detail in the red channel, more so than comes out in the final post-processed image. I'm not sure but based on this can I do a better of job of getting all of that detail from the red channel to show in the final image?

Any advice on how to produce a better image with this nebula would be much appreciated.

I've used Siril and Gimp so far but I also have a trial licence for PixInsight I can use too.

Thanks!

The image processing makes such a huge difference, I spent hours pouring over youtube videos and tutorials which netted some significant improvements in my images. It's amazing what you can do with data that you didn't even know was hiding in your images.

Great efforts with M42, really got what looks like some deep reds there in the 2nd image. Did you use a h-alpha filter at all? I think the next step for me will be to take some shots with (and buy..) a ha filter and take some shots without, then combine into a HaRGB photo. I don't know if that means I'll need to take two sets of darks/biases/flats as the optical train will change, that would add a lot of time to the process and a lot more cloud-free sky required..

I'm not there yet but also have aspirations for a proper zwo cooled cam, definitely an improvement on the DSLR by the sounds of it.

This hobby goes like something like this:

- Buy expensive gear

- Learn, practice, create awesome image

- Look to improve further and reach the next level of photo, which requires new accessory / filter / equipment

- Buy expensive gear

- Learn, practice, create awesome image

- Repeat...

😁

11 hours ago, Enceladus Dan said:

Hello Will, 

I'm still new to this, 16 months into my journey. For me my only experience in Astronomy was using my eyes, when my job took me to remote places around the world. On top of learning how to use my gear I bought, I had to learn image processing, as I had no experience what so ever. 

I have recently been getting my fix of AP during this bad spell of weather were having, by following some youtube tutorials on Pixinsight by Lukomatico. They are very good and easy to follow, all data and tools needed are provided (just need pixinsight free trial) 

I am so amazed at how much better my images are after, I will definitely be buying pixinsight. I just need to work out if I get an astro cam or PI first. Choices, Choices. 

These are the Images from following the tutorials. Now I just need some clear skies to catch some of my own photons again. Seems like it's been forever. 

Clear skies

Danny

Wow, your photos look spectacular! Very nicely done! Love the colours and vibrancy.

I was waiting on a trial licence from pixinsight, so I got going with Siril and GIMP and followed these tutorials:

Siril - Full image processing (pre-processed with scripts)

The Budget Conscious Astronomer: Background Extraction using Gimp - YouTube

Star Reduction in GIMP — a tutorial using Wavelet Decompose | by Paul Bleicher | Medium

Which helped me produce my first image of M31, I'm proud of it but as always there is a lot to improve on.

Kit: Sky-Watcher Evostar 80ED DS-Pro, 600D astromodified, HEQ5 Pro, 0.85 reducer/flattener, no filters.
200s lights.

16 hours ago, The Lazy Astronomer said:

TL;DR - the L-extreme is designed for emission nebulae and would be of little use for galaxies, the exception being to add some Ha data to a broadband capture.

The longer answer: the L-extreme is a dual narrowband filter with 7nm bandpasses around the Ha and Oiii emission lines (Oiii actually has a couple, but I believe the L-extreme focuses on the 500.7nm emission).

The Ha and Oiii emission lines are caused by ionised gases which emit light at specific wavelengths. The L-extreme blocks out ~95% of visible light to isolate just a small section around those 2 emission lines, thus significantly increasing the contrast when photographing these regions. 

Galaxies, on the other hand, emit light across the whole of the of visible light spectrum, and so are best photographed without the L-extreme. That said, a good number of galaxies do have some quite strong Ha regions, so it can be of benefit to add some narrowband data into a broadband capture to accentuate these areas (most would do this by adding the Ha data to the red channel when processing).

To answer your other question, you can choose to either create a full false-colour narrowband image, or to blend the narrowband data into a true-colour broadband image. When doing this, the images would be stacked separately and the narrowband blended in during processing. As above, Ha would be added to the red channel, and Oiii would be added to green and blue.

Thank you and everyone for the advice here!

That makes a lot of sense. I've also heard that using something like the l-extreme with a 600d (modified) will require long exposures since its such a narrow pass,and as such the images get quite noisy.

So perhaps sticking to a ha filter will be best, as a starting point as you say. If I'm going for galaxies but also some emission nebula. Then combine with a true-colour broadband image.

Are there any HA filters you or others would recommend on that front? for my setup of astromodified DSLR, 0.85 reducer/flattener, ED80 scope?

Hi

I have an Astro modified 600d dslr, ie allowing h-alpha through now. I’ve been advised that an optolong l extreme filter would be an excellent choice for capturing detail and colour from galaxies and nebula. I’m in a bortle 5 area, and have a 80ed scope with 0.85 reducer. 

I understand the filter works by allowing two different frequencies of light through, while blocking others (presumably light pollution and everything else).

Does this suggest that galaxies only emit light in those two different specific frequencies? Hence why you’re able to capture a complete looking image even with the filter? Or perhaps they are just the two most prominent frequencies emitted by galaxies. 

Related to that, when capturing images would you usually only take images with the filter or would you take both with and without and then stack them all together? 
 

Thanks! 

3 hours ago, LaurenceT said:

Yes, the strain on finances can be extreme especially when you're no longer earning any money. I've financed the new hobby mostly by selling off my photography gear that was sitting in the cabinet unused.

You asked for a link to the first ever DSO image:

 

Looks incredible! Awesome first effort. Thanks for sharing.

1 hour ago, LaurenceT said:

The learning curve is indeed incredibly steep, even as a lifelong hobbyist wildlife and macro photographer with all the attendant complexities I've been absolutely floored by the technicalities of astrophotography and astronomy.

My age of 75 has somewhat been against me as a beginner and it may sound weird but I was actually concerned that I would pop my clogs before producing a deep sky image, I managed to get one last week!

I certainly will have a look at your blog and welcome to this brilliant forum.

It really does seem like a hobby that you can as far as you want to, both in terms of complexity but also the strain on your wallet! I think that only adds to the allure.

That's fantastic you were able to get your first image. I'm not sure if you've already shared anywhere but I'm sure we'd all love to see how you got on.

1 hour ago, John Wick said:

Same story for myself, started last December with a MSM tracer for Milky Way imaging (live in Bortle 3), just purchased the Star Adventurer ii Pro (2nd hand, never been used it seems, £250) Also just purchased the Samyang F2 135mm, brand new £380. Waiting for the opportunity to test it all.......do have an itch for a goto mount though...

Ah good luck! You are lucky to be in a bortle 3 area I think, hopefully that will help you get some great results!

I'm in a bortle 5 area, so I'll be looking in the future for any filters that might help me remove the light pollution. Based on other folks results it looks like should be able to produce something though.

11 hours ago, MarcuSmythe said:

I am in the same position of venturing my inexperienced foot forward in that direction.  If it were not for the constant clouds I would even gain some experience! Good luck.

The only upside to the clouds is that I now feel over prepared for the my first imaging session, if there is such a thing.

Good luck and would be interested in how you get on from one beginner to another!