The-MathMog

2 hours ago, Louis D said:

That's wild.  I live over 25 degrees south of that, so we have plenty of astronomical darkness even in the summer.  It would be about the same as being in Cairo, Egypt on your side of the pond.

Sure is. It is easy to forget how high of a latitude Denmark actually is, compared to how the weather is. We basically had no snow this winter. That is because, looking at big weather-systems, we are basically sheltered by Norways mountains. The same latitude in the Americas, would be well into Canada.

7 hours ago, Ricochet said:

Before mine failed, I had never heard of a failure and I have no hesitation in continuing to use them. In regards to what might be a more common issue of one that has seized after a long time left in the locked position, I would recommend unlocking and relocking regularly.

Great news. Check it is now working properly on something cheap, like a standard 2"-1.25" reducer before reclamping on the coma corrector.

Yeah, definitely think I will. Almost certain that it was a case of being locked in place with big temperature-shifts for a while. And it is working fine and dandy again.

7 hours ago, johninderby said:

Glad you got it sorted. 👍🏻

I second the idea of not leaving it clamped when not in use. 

Might do that. I do have the telescope and mount permanently set-up though, to minimize any changes in image-rotation, balance etc, and setup-time. Right now I can just bring the tripod out, then the mount with the telescope attached, bring cables in, and I'm pretty much rolling

10 hours ago, almcl said:

Great that it worked, well done!

Indeed, having to send it off for repair or the like, was the last thing that I wanted to do, with 4 nights of clear night still to come, and astronomical darkness ending in less than 2 weeks tops (the downside of living at a latitude of 57 degrees..) 😅
Thanks again.

I own the ES HR Coma Corrector, and it works great for my camera/telescope setup, when the sensor to objective distance is correct. I've read in the manual that the distance isn't AS crucial with DSLR's (for some reason unbeknownst to me), but if you are still struggling with coma, then the recommended distance is 55mm from sensor to objective.
And great images for such short exposures, but with a beast of a scope like that, no wonder.. 😅

On 17/04/2020 at 19:58, almcl said:

My solution which you may like to try if you're feeling brave, was to tap the release handle smartly with the plastic handle of a screwdriver while holding  the trapped item.

I got it loose! Thanks for the help!
I used some duct-tape on the coma corrector, and then made an improvised double-sided tape for grip. Then as suggested I gave it some good taps with the end of a plastic multitool, and it came loose in no time.

Thanks a lot you all!

I own this one, and have spaced it from "A", and that works fine

19 hours ago, Louis D said:

Is this a common problem with the Baader Clicklock?  Up until now, I've only read glowing praise of the BC.

First time in a years time it has happened to me, and could only really find one other thread about it, so not sure. It has been working amazingly until now.

12 hours ago, Neil H said:

Hi how about putting some double sided sticky tape on the coma corrector so you have a bit more grip the only down side is cleaning it off after 

I'll try that, but as mentioned, at times when applying enough force, the whole Clicklock will just turn around the coma corrector, showing that it isn't holding it THAT tight. And I can't really get a grip on the two parts of the clicklock that needs to rotate from one another either.
Just cleaning it if it works, will be worth the hazzle ^^
 

8 hours ago, Erling G-P said:

+1 for trying to heat it with a hairdryer.  Whenever I've had mechanichs having problems with stuck bolts on my cars, they usually end up heating them, which always seems to work.

I'll give that a go, cheers.

5 hours ago, Ricochet said:

Contact Baader. I had a clicklock break, luckily when it wasn't holding anything, and there was no way of releasing it.

5 hours ago, almcl said:

I have had this happen a couple of times in the last fortnight, after almost a year of blameless service.

My solution which you may like to try if you're feeling brave, was to tap the release handle smartly with the plastic handle of a screwdriver while holding  the trapped item.

If that doesn't work, my other 'goto' for stuck items (usually my coma corrector into the the camera adapter) is a nylon strap oil filter wrench.  This is even more risk prone bur, for me at least, has always worked without damage.

Darn, I sure hope it doesn't come to having to have them repair it... F the clicklock, the ES Coma Corrector is the heart and soul..

I might try those suggestions of yours. Not sure exactly what nylon strap oil filter wrench exactly translates to in danish, but I'll have a look. Only issue is too, as said, the coma corrector is very slippery, and there isn't really a part of it, that is easy to get a good grip on.. And even if I hold it, the whole clicklock just seems to turn around it, as if its grip is not THAT tight.

I'll try to see if I can release it after this session, as it will then have had the whole night to cool down. I think the last time I tightened it was during the night, so me trying to release it when it is maybe 20 degrees hotter could cause an issue? 

So, I wanted to change the distance from my camera sensor to my coma corrector, but before removing the assembly from the telescope, I was unable to release the lock on the Baader 2" Clicklock... When trying to turn it, it just screws off of the telescope (as that is how it is mounted).
I can remove the other parts, and easily take the whole train off the telescope, but the click-lock is stuck to my coma corrector, and I can't for the love of me get it to release... If I use enough force, the Clicklock just slowly slides around the coma corrector, and it is slippery as hell, so I can't get an amazing grip either.

So any advice on how to do this, before I use excessive force and risk damaging either part?

My scope is still fully usable, but I currently can't change orientation which is quite annoying... hmmm
 

I had something similar to this recently, and found out that it was an asteroid that slowly moved through the picture through the night. So when LRGB was taken it was in a slightly different spot. I don't have enough knowledge to say that this is certainly the case, but a possibility.

That is one stunning image right there! Great job!

As mentioned, a bit green/yellowish to my eyes too. I don't really see much of the uneven background though. But great data! And I couldn't help myself, having a twiddle with it in photoshop. This is how I personally would color-balance it
Using the color balance tool, until the background is nice and black, giving my eyes "rest" and then looking at it again. A curve, boosting the blue areas of the galaxy, and then a slight saturation boost + some local sharpening on the dusty parts.

1 minute ago, oymd said:

I will try and fit the SW 0.85reducer tomorrow night if clear. 
 

can I please check regarding cal ration frames?

if I fit the reducer tomorrow, and redo the targets I took over the past week, and I keep all my settings the same, temperature, exposure time etc, DO I NEED TO REPEAT THE DARKS, FLATS AND DARK FLATS with the reducer attached?

or I can use my existing MASTER calibration frames that were taken WITHOUT the reducer and stack them with the NEW Light subs taken with the reducer?

You'd need to redo the flats yes. Anytime you change your setup/remove camera/remove filter, you need to take flats again, as they only work when you keep the imaging train the same as the lights.
Darks you don't need to take again. Not sure with dark-flats as I've never used those.

Flats should be taken after each session, as dust can have changed positions. Darks you can reuse, if the settings are the exact same, hence why some people make "dark-libaries", where they have a collection of dark frames with different exposure/temperature/gain values.

2 hours ago, JonCarleton said:

I found an image in the trash.  This is an example of an unstretched sub from an earlier session.  Still struggling with focus issues at the time.

That image doesn't seem all too bad. If you had a lot of those, stacked properly, I'd think that would yield good results.

Have you tried stacking with DSS?

And cheers - all trials and errors the last few years
 

I

2 minutes ago, oymd said:

My gear is AZEQ6 Pro, ED80 and ASI294MC Pro. 
I have the 0.85 SW reducer, but have never tried it yet, as I am just getting into imaging, and do not want to mess up my imaging train until I get some more experience. 
I posted over the past few days some good first results, but they were all 30 second subs. 
I wanted to push the sub duration a little to see if that allows more data collection. 
I really did struggle with the FOCUS AID in APT. 

Pretty sure it’s my lack of understanding. 
 

I ended up putting the bhatinov mask back in and manually adjusting focus. 
 

Could not get my head around FVMH and LWH, or whatever they are called!

I'd say, just continue using the Bahtinov mask. If of good quality, it can produce near perfect focus. There is even tools (sharpcap has it), that analyses the Bahtinov spikes, and help you focus.

When working with FWHM (full width half maximum), just get the number as low as you can, that is the best focus.

Alright. The 0.85 SW reducer, will definitely help your image, in the edges. I'd personally go for it, as assembling and disassembling an imagetrain can be training in itself.

I read about someone, who when processing an image, would get to a point where he was happy with it, and then delete it. Just to do it over again. If he could do it once, then he should be able to do it again, and use that part as training (can be a bit extreme, but I hope the point comes across :D)

 You say that you take flats too? It seems that they aren't calibrating the image properly, as there is still quite some vignetting and dust visible

But again, focus in the center doesn't seem too shabby, might just need some fine tuning.

29 minutes ago, kendg said:

On android I use Mobile Observatory pro. Does what I want and has notifications with events for 7 days.

Also does aton of other stuff too.

Thanks, I will try giving that one a look.

27 minutes ago, JonCarleton said:

Alas, I am an avid disk cleaner and no traces of my failures survive for long.  I am using a SVBony305, and used a 30 second exposure with about 60% gain.  By contrast, I use 1ms with 0% gain for moon shots.  This is the moon shot I stacked, though a bit overzealous in the GIMP post-processing.

I might get another shot at the nebula tonight and will post the results.

Nice image btw

Depending on the camera, as I am not familiar with it, it could definitely be a possibility that, that is too long an exposure / gain. As long as you are capturing files in a raw format, with the highest bit possible, you almost always pull out a lot more data, than is evident at the beginning. If you've overexposed, you can't really recover those areas.

Here is an example of what an image looks like for me, straight out of DeepSkyStacker - and then what a quick stretch in photoshop reveals

Hey there.

I am curious, as to what media or software you guys are using, in terms of knowing when certain alignments, conjunctions or events happen?

I actually had a clear sky, a couple of days ago, when the conjunction of Venus and the Pleiades happened, but I didn't know until the day after. I even thought: "what a nice clear sky, but naaah, the moon is way too bright tonight" (I mostly shoot galaxies these days).
So I am actually a bit bummed at missing that.

So, what good sources are you guys using? I am mostly using stellarium, reading a bit on the forum here, and looking into SkySafari Pro (will that give any clues?). Or is it simply by chance figuring it out 😅

Thanks in advance.

From the dates you just stated, yesterday and the 25th of march, I would say that the moon is definitely the dominant factor here, and that you can't use the comparison there.
The moon as it is, is nearly full and will significantly brighten the sky, hiding a lot of details of faint galaxies. Back at the 25th, the moon was under the horizon basically the whole night.

So I would say, wait until the moon is crescent and/or below the horizon, and then try again

I've heard a lot of good things about this filter too, so give it another go

I would try that yes, as you can definitely end up overexposing some targets. Especially bright ones like the Orion Nebula.

What camera did you use, how long was the exposures, how high gain etc?

Even though M42 is quite bright, it is actually a hard target to expose right, without blending several exposure ranges, as it has a veeery bright cores, but faint flimsy parts.

The best results I've gotten, has been combining short exposures of 10-30 seconds with long 2-4 minute ones, or even adding even longer HA ones.

If you got a picture you could share, that would help too. But experimenting is always a good idea.

The focus seems alright. In the middle. But at the edges, the stars definitely start to suffer from an uneven flat field.

What is your gear, and are you using a field flattener?

The star shapes can definitely be affected by the 90 second exposure. It doesn't even have to be a steady drift, but small errors in the gear of your mount even. So best is to judge from shorter exposures with high gain/iso to see if focus is good.

Keep it going, and as others have said, keep experimenting and be patient. It will bear fruit!

One tip in terms of the focus you can try, to get it more consistent. Try using the camera in daytime, and focus on something in the wast distance/horizon. Then mark where that point actually is. That'll give you a baseline of where "infinity" is on the camera.

That, or you can try making your own Bahtinov mask. If you don't already know, it is a mask that you put in front of the camera/telescope, that will help you focus. There is plenty of templates online that you can print, and cut out yourself if you don't want to buy one. I've been using my own homemade one for my 150PDS for the last 3 years now, and it works wonders

A "quick" comment, as I don't know too much about it..

But the pro for off axis guiding, as far as I understand, is that since you are guiding from the same light-source (the main mirrors or lense in the telescope), you can get more accurate guiding, as there will be less errors introduced by slack and loose connections. If the connection between the focuser and the telescope slacks a bit, it will move both the camera and the off-axis-guider, basically cancelling that out. Where as if you have a separate guide-scope + camera mounted on the telescope, any slack,"bending" or tugging due to cables, can introduce errors, where the camera will then guide the mount, even though it is not necessary. Giving you eggy stars in your images.
Making sure that all connections are very tight, and that cables aren't dangling, is then a lot more important with a separate guide-scope.

The downside for off-axis, is that the camera will receive a lot less light, than having a dedicated scope. So you will tend to have a harder time, finding bright enough stars for guiding. Having to add another element between the focuser and the main cam, can also introduce problems with reaching focus, or even weight limits.

Anyone feel free to correct me, if I've said something wrong here haha..

15 minutes ago, Peart said:

Thats what I thought it was. I have a question about flats I will struggle to get them during the day as I heard you cant move the scopes orientation so would a white shirt over the lens and a laptop with a white screen held up to it work. Thanks for the help. 

Indeed, that is how I take them, so I don't have to wait till dawn!

Knocked, wind, periodic error (quite harsh one), balance issues and backlash? The cables could be a cause too. Best to attach them as much as you can to the telescope, with them still being able to move as the telescope slews/tracks.

When I got my Celestron AVX mount, I often saw star trails, more often with longer exposures, logically, but not always. And I found out that it was because of periodic errors in the wormgear.
The AVX has Periodic Error Correction learning, and after I did that, and applied it, I went from having to scrap every 2-3 frames, to being able to do 4-5 minute exposures without guiding, as long as polar alignment was very good.

Might not for certain be the issue here though.

Because of the current situation, I have, as many of you guys probably have too, spend a lot more time under the stars when possible.

It has literally been over a year since last I was out doing some astrophotography because of work.

So here is my second take after the long break, NGC 3344 (The Sliced Onion Galaxy).

Initially I thought it would be a lot fainter than it was, so it was basically a shot in the dark, of just trying to get back at doing this.

But the final image actually showed a lot more detail than I would've hoped for!

Spring lent a lot of clear night, but those seems to be gone already. I would've hoped for a few more hours to add some more luminance data to it, as I did have to push it quite a bit.
I am not too happy with the shape of the stars either. Guiding was not very stable through the night, even though balance and polar alignment seemed to be good. Might need to update my Celestron PEC data? 

Any advice or feedback is very welcome! 🤩

NGC 3344 (Sliced Onion Galaxy)
_______________________
Image:
Luminance - 13x16 min
RGB - 2x16 min each
Flat and Dark calibrated
Gain 111
Offset 40
Total Integration - 5 Hours 4 minutes  (LRGB)
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Gear Used:
Skywatcher 150PDS
Celestron AVX Mount
ZWO ASI 183MM-Pro
Baader 2'' Neodymium Filter
Baader 1,25'' RGB Filters
ZWO Mini EFW
Explore Scientific Coma Corrector
ToupTek Camera G-1200-KMB Mono Guider
Orion Mini 50mm Guidescope

______________________
Software:
Sharpcap
PHD 2
Photoshop CS2
Deep Sky Stacker
Stellarium/Stellarium Scope
Astrotortilla