Datalord

1 hour ago, DaveS said:

some interference between Sequence and the Trius drivers, possibly Maxim as well.

I really don't trust Sequence. When it works, it is indistinguishable from magic. When it doesn't, your mount parks, camera turns off and .Net exceptions crash everything. I use sequence for autopoint files and I have used it for making MLPT runs. Those I send to autoslew, disconnect Sequence and use APT for my camera run.

Andrew, just to make sure I don't make assumptions on my fail to understand the geometry, I made an astrometry solve of the exact image (non-egg) of the time above, mapped that to the skychart at the time and drew the frame with "up":

Does this match your parallactic angle theory?

1 hour ago, glowingturnip said:

doesn't help with fixing the root problem of course, but you can fix this easily in post-processing - split out the R, G and B into individual greyscale files, star-align them to each other (use the green for reference since you have twice as much green on your DSLR), then re-combine them to RGB

I'll try that!

4 hours ago, ollypenrice said:

When boosting star colour I sometimes get an effect very like your second image. I don't see it till I've done pretting aggressive boosting but it must be latent in the stack. This is with mono camera and refractors. I'm afraid I don't know how it arises.

So, this time around I took a photo from last night, just one frame. background extraction and a nuke in PI:

Very apparent, but this time on a different target, which is a different place on the sky (Eastern Veil vs M31 in the previous). The colour location changed with roughly that same angle as the difference in the target in the sky.

3 hours ago, andrew s said:

parallactic angle

I have no clue where that is, even after trying to read up on what it is? The above picture from last night is taken near zenith.

Very interesting. 

You're right, the egg might actually be part of the problem. I have another set from last night with considerably rounder eggs (fixed the chicken), so I'll check it out. I will say this has been a problem on all images I have taken from the very beginning with the RASA/QHY combination (this time I have different spacers than last), I just didn't "care" the same way I do now.

So, I went back and looked at my very first image of the rig, with the same target and with very bad focusing.

What's striking to me is that the colour is wrong on exactly the same sides, on round stars. Part of the story is that the camera malfunctioned AFTER this picture, and I got a full replacement, so the camera can't be the root cause. The rotation of the camera on each image is also different by about 45 degrees.

Another difference: On the original image I used just an IR cut that comes with the RASA, on the one above I used the LP RASA filter.

🙄

On 28/06/2019 at 05:07, Waldemar said:

That is bad...  I hope there's no damage

Again, the heroes working at E-Eye got the mount back to within 5 arcmin PA and it seems like everything is good. I got it running a 126 autopoint file, resolved 124 of them and all targets are in the frame immediately.

And for good measure, it's ticking away now on NGC 6946 and the guiding performance is for me incredible. It is surreal for me to see these numbers when I had to fight the Celestron so hard to get even a third as good as this.

I have my RASA set up in the backyard again and started gathering some data. This time around I want to fix a problem I had in my old pictures. I think it is chromatic aberrations, but how do I fix it? Why is it coming? When I focused the scope, it looked like the collimation was fine.

ignore the egg shape, that's a different problem. 🙂

5 hours ago, brenski said:

 

wasn't planning "untracked" - my post above suggested the Sky-Watcher Star Adventurer. But I was told that the Takumar 200mm would be asking too much of that tracker mount.

■ would the takumar 200mm work better with the iOptron skyguider pro?

■ what software would i use with the iOptron skyguider pro?

Ah, ok, makes sense. I don't have firsthand knowledge of them, so I can't tell. But a quick search on astrobin: https://www.astrobin.com/gear/25666/skywatcher-star-adventurer/

Check out those pictures and the gear they used.

As for software, I can again only use my own preferences.

• I use Astro Photography Tool for camera and acquisition. $18 per year and I find it better than, say, MaximDL which I had to purchase for $500 for my ASA mount.
• PixInsight is my preferred tool for processing, a bit of a dog to get started with, but excellent tutorials around and it made a giant difference for me.
• Photoshop for the final touches on my images.
• Carte de Ciel, free planetarium software for setting targets for the mount.

While it may feel bad to pay for all this software, your final picture is a result of your processing skills as much as your acquisition. It literally takes years to get good at it.

Great, for DSO and nebulae, definitely the ED. I would not buy a modded DSLR, but a cooled proper camera as future investment. Before that, though, a filter changer and some narrowband filters...

Maybe an important question I forgot to ask: What do you want to photograph?

If DSO and nebulae? Great with a refractor.

If planetary, you need to go a completely different route, at least on scope.

As someone who has started small and upgraded to what amounts to a very decent new car worth of stuff, I concur with the above on the mount side. Get as much mount as possible, it is the first and last point of a good photo. Camera wise, stick to you canon until you absolutely must go to a cooled solution.

And yes, a small refractor is by far the best starting point. 

And time and patience and money for software licenses for PixInsight and Photoshop. Good luck!

200mm for untracked AP seems optimistic at best. Have you looked at things like the iOptron skyguider pro?

Nope, I'm saying the roof hit the mount and pushed it back. I can only hope the screws were giving in enough not to damage the scope. 

Ah, well, fun and games. Turns out that for whatever reason, the mount decided go upright when I turned on the power, just as the roof was opening. My PA is now 200 arcmin off. Just have to love this stuff...

Another bit of IT fun. Again, the software is supremely unhelpful in figuring out precisely why it is doing what it is doing.

Last night I had a good run. Turn off the scope in the morning, etc. Tonight I spin it all up and try to find the same target. Doing a sync. Suddenly it is wildly wrong in tracking. This is just tracking for 60 seconds:

Literally untouched by human hand, which means this is all software problems. I've done this dance a few times and I am no closer to finding the root cause. Eventually I will reset enough and load the pointing file at the time where divine intervention will help me and all is good, but I never really know when that will happen.

15 hours ago, DaveS said:

Very good to hear, you should be able to get good long subs now with the PA sorted.

I should be joining the DDM85 club soon, since Rupert has got the ex demo one back here. That'll give me two DDM mounts, twice the IT "fun" .

My IT fun is still not over. I find the software has a nasty tendency to crash and with mltp, a run of 5 hours takes about 20 minutes to initiate. And last night it somehow took down the telescope driver, which crashed the connection to the roof, which initiated a park and roof close. 😱

I ended up guiding with my old software and the result is really, really good. I don't see how I can benefit from going under 0.3" RMS anyway, the seeing simply can't be better than that. 

hmm, clicked submit twice and I have no idea how to delete a post...

23 hours ago, HunterHarling said:

How does it look?

Worthy of print and a spot on the wall. Well done.

Well, I'm going to declare success. The good gents at E-Eye did an adjustment and this time it hit the nail for real. Tonight I managed to get a full 71 point autopoint run to resolve all points in the sky and give me this:

At 5:54 local time Spain I captured the proof in this unguided 1200s exposure:

I can't find fault with it. While I'm happy I finally got it, I'm so tired with the journey so far to really celebrate. But in fairness, this is amazing and bodes extremely well for the future.

On 20/06/2019 at 23:56, Datalord said:

This is what I got from a new config tonight:

As an example of the things I face, this turned out to be a fluke. For whatever reason, having 15 points in the sky, it decided on this one occasion to give me this PA error. I still had some issues with the images with rotation I couldn't understand, so I ran another set and suddenly I'm 93 arcmin off. Full of bewilderment, I go back to this set, load this error file and it tells me I'm 80 arcmin off.

Thing is, I can literally do the same action multiple times and get a different result every time. The absolute definition of madness.

Ah well, those NSA spooks are probably snooping worse things than my use of star catalogues.

1 minute ago, JamesF said:

Probably still daylight for them.

James

I meant at E-Eye in Spain. 🙂

Worked, thanks!

I better wait downloading it until tomorrow. Not a nice citizen to take all the bandwidth during shooting time...

I tried figuring out how to get USNOA2, but either I'm stupid or the links don't work? http://tdc-www.harvard.edu/software/catalogs/ua2.html

1 hour ago, vlaiv said:

Any way to sync the mount from custom coordinates?

Yep, all of that is working. 

Maybe I need to explain that the software works by making an autopoint file with points all over the sky. Then it takes a photo of each, platesolves each to get an error file of the entire sky, then uploads to the mount. If this platesolving doesn't work, it's pretty much game over.

Second case is for the unguided function. you give it a target and a set of exposures. Then it runs the trajectory of the target, takes images and plateosolves to see the errors. This is then used to make sure the encoders compensate for misaligned PA and flex. Again, this is 100% depending on platesolving working.

And the absolute idiocy of it all is that I can always just upload an image to astrometry.net and get it solved within a minute, but these 🤬 pieces of software can't figure out to extend the search a bit further.

5 minutes ago, andrew s said:

40x40 8s not too extreme. How long are you exposing for and at what arc secs per pixel?

Regards Andrew 

No, it's not too bad, but while you are fumbling around with PA and sky solving and everything else, it quite quickly means you are pointing 40" wrong and suddenly solving fails completely. I'm imaging at 0.52 at bin1, but for solve pictures I do 5s bin2 at 1.05.

I guess I should be clear: Solving is easy when the scope points the right place. less than a second. But I need to have it solve for when it is misplaced by some reasonably wide margin.