Had a successful but long night last night and this morning working out the kinks to see if I can get guiding working through the 8x50mm guidescope using the toucam.
After fiddling with focus, alignment to the main scope, sorting out polar alignment, finding things with the DSLR and the guidecam fitted, playing with EQMod and stellarium, I found out a few things....
Maxim DL doesnt want to drive the DSLR and the webcam at the same time.... used the EOS II driver on cam 1 for the 1000D and the WebDS camera for the toucam on camera 2. Wasted at least 1.5-2 hours stuffing around with this and got nada. Thinking the lappy doesnt have enough graphics and processor grunt to run it all.
Ended up getting PHD working at the same time as the canon utility and spent maybe an hour playing with and learning PHD and all of a sudden (after I stopped being impatient and did the right steps) guiding was all green and good SNR. I could also see and hear the scope pulse guiding through the eqmod interface after I adjusted the pulse settings.
End result was the guiding was working well, so with only an hour or so before sunrise, I tried some 60 secs and some 5 minute subs on Eta Carinae. I had 5 x 60 secs in the can and 5 x 5 minutes but could only keep 2 of the 5 minutes as light cloud drifted in.
More importantly, for half an hour, the guiding was working like a charm!!! The only way is up from here.
So, here is at least some sort of result. I am not too concerned with the quality or the processing for now, simply rapt that I got some tighter stars for longer than 30 sec subs for once. Can't get the MPCC inline without modding the 2" adaptor to cut it down, so I simply used the 1.25" adaptor and trimmed off the outer third of the image with the most coma in it. Still a bit of work to sort out the focus and the processing, but at least I have a plan now on how to get it all cranking (after investing 7 hours playing around trying things out).
Thanks for looking, as I said, I am not too concerned with quality at the moment, more for the practice and testing of the guiding, but feel free to comment, good or bad....
Image Details:
Date: 27/2/11
Time: 4:16am - 4:21am
Subject: NGC 3372 Eta Carinae Nebula (Keyhole/Homonculus?) 60% cropped to remove outer coma
Telescope: Black Diamond 200mm Reflector @ F5 on HEQ5 Pro
Camera: Canon 1000D
Capture: Canon EOS Utility
Guiding: YES - Toucam on 8x50mm finder using PHD
Frames: 5 x 60 second at ISO 800, 1 x Dark Frame
Processing: Registax 4 only for gamma, gimp for black point.
Sorry for such a long post,
Cheers
Chris
Last edited by Screwdriverone; 27-02-2011 at 10:57 PM.
Nothing wrong with a long post Chris. Its good to hear the exploits of other astroimaging tragics
And great to hear you had a success. To increase your success rate you might want to consider giving Registax the flick, downloading Deep Sky Stacker and upping the number of darks.
The real trick is to nail your polar alignment. You can ask others here and they'll attest to how nasty I am with polar alignment. I make sure the star doesn't move at all for 5-10 minutes at a time.
Then, you should be able to get away with 2-2.5 second guide exposures so that you're not chasing the seeing, and, the mount should happily track away.
I will give DSS a go, I found that with only 5 x 4Meg subs loaded, albeit at some ridiculous pixel count of 3382 x 4452 or something, Registax ground to almost a halt on my laptop, that as well as the fact I didnt really do anything else in there while stacking may mean I will flick it.
I would have like to have processed my M42 pics as well, but at 30secs and with no guiding, they were......well......a bit crap, so I moved on.
Now I have a good platform that guides so I can maximise the time when I do go out to try and play with the exposure settings and lengths to continue improving.
I was trying 5 minute subs at ISO 400 but even these were looking washed out.....is there a better setting, say ISO 100-200 for say 10 mins?
I would be happy for some advice on the sub lengths and ISO settings if anyone feels like sharing?
The real trick is to nail your polar alignment. You can ask others here and they'll attest to how nasty I am with polar alignment. I make sure the star doesn't move at all for 5-10 minutes at a time.
Then, you should be able to get away with 2-2.5 second guide exposures so that you're not chasing the seeing, and, the mount should happily track away.
The end result is worth it.
H
Thanks H,
Great to hear from you.
I had PHD set for 1.5 secs, but with the toucam not running in LE mode, I simply had the camera controls set to full autoexposure and took a dark frame for PHD to lock onto the star and give me SNR of about 6.5 every time.
Once I stopped fiddling while it was calibrating the guide interface, PHD simply locked on, went green and sat there staying within +- 0.15-0.2 of the star (I was watching it closely) while the canon utility clicked away with the 5 x 5 min subs at ISO 400.
I know the polar alignment was good as I adjusted with my method through the binos at the Beta Hydrus, 5 past six stars to the SCP as per my tutorial, got the mount pointed and then double checked with the polar scope and all 4 stars in the Octans asterism on the polar finder were spot on. When watching PHD, the guide star didnt move the whole time and stayed pretty much in the centre of the cross hairs and box. (oh yeah, and I remembered to mark the tripod leg positions on the ground before I packed up)
Pretty easy (and funky) when it all comes together, felt chuffed at 4:00am when it all started running like a bought one....
Thanks for the comments and the tips....now I just have to chop the 2" adaptor so the MPCC can be used to get rid of the coma.
Seriously, drift align for "perfect" polar alignment. Polar scopes will only get you so far -- you will end up with field rotation in your final image after lots of exposures.
While the rotation can be corrected for using software, you will end up with swirls of noise in faint regions of the image.
Anything worth doing, is worth doing properly -- no baby steps!
1. counterweight shaft horizontal;
2. point scope so that it is parallel with the RA housing on the mount (near the meridian);
3. watch a star drift;
4. make large-ish adjustment to azimuth knobs one way or the other;
5. if star drifts less over a given amount of time, then, make another adjustment;
6. if star drifts more over a given amount of time, then, make adjustment in other direction;
7. keep iterating until star doesn't move at/near meridian;
8. point scope somewhere with 20-degrees of western or eastern horizon;
9. watch a star drift;
10. make a not-too-large adjustment to altitude one way or the other;
11. if star drifts less over a given amount of time, then, make another adjustment;
12. if star drifts more over a given amount of time, then, make adjustment in other direction;
13. keep iterating until star doesn't move at/near horizon;
14. swing back to zenith/meridian and double-check star doesn't move;
15. if star still moves, go back to step 4.
Hmmm, yes master I will pick up my weapon and strike the drift down.......and then my journey to the dark side wil be compleeeete!
Thanks for the tutorial I will get my chopsticks and catch some flies before trying it out. A quick question though, when I check for star drift, should the mount be sidereal tracking or tracking off? I thought the tracking should be off so I can see the star drifting down the illuminated reticle line which has been rotated to line up with that axis?
This is so that you can see how far off your alignment is. As for the reticule, you can line it up by moving your scope up=down, left-right with the hand controller and watch the direction the star moves in your field of view. Or if you're like me your initial alignment is so far off that you'll be able to line up your reticule lines without moving the scope!!
Once you've lined up your reticule, just follow Octane's instructions. They're the simplest and most concise I've seen!!
Chris, as Mario mentioned, the tracking should be on. You want to see how well/poor your mount is tracking.
If you ensure that your guide camera is aligned north-south, east-west, the star should move either left and right or up and down. You don't necessarily need to worry about which direction it moves in as all you're concerned with is seeing /some/ kind of movement so that you can make adjustments to your mount and compensate.
As for measuring the actual movement, you can use an on-screen reticle. I use StarTarg as I like that I can move it around and enable a timer on it to monitor star movement vs time. You can also enable the grid and/or bullseye in PHD Guiding, or, perhaps even use our own Al Sheeny's on-screen reticle software that he's so kindly given to us for free.
I use the standard double-line reticle that StarTarg provides and by using the timer, measure the amount of time it takes for my star to cross from the centre of one reticle line to the next reticle line. For example, if it takes 30 seconds to move, I make a known adjustment (such as one complete turn of the azimuth knob) to my mount, put the star (or another star) back on the centre of a reticle line, and measure how long it takes. If it now takes 15 seconds for the star to move the same distance as it did previously, then, I know that another complete turn of the azimuth knob in the same direction as I moved it before, should get me pretty close. Then, it's a matter of fine tuning (and not forgetting which way you moved the knob!).
The best thing you can do is to make a large adjustment the first time around, otherwise you'll be sitting there scratching your head wondering if the star is moving less or more or not at all. Typically, for me, this means 2-3 rotations of the azimuth knob on my G-11.
I will definitely give this a go next time to make sure I am spot on. I must also remember to collimate more accurately too as I noticed the twin vanes on the diffraction spikes also and I didnt really check this too well as I was focused on the guiding scenario for so long.
Thanks for the tips, the "Octane 15" is going into a file which I can call up next time for reference and I dont have to go digging around for it.
I gave the "Octane 15" a go last night and had my mount pretty well aligned in about 30 minutes. When I checked at the end of the night using Sirius, it had only moved to the edge of my reticule "box" after 10 minutes. For me this was one of those watershed events where you finally start to understand what you are doing. I don't think I've ever had my alignment that close!!
Unfortunately it was only a visual run last night and since deciding to maybe do some imaging tonight we've had storms come through Brisbane and rain and showers are predicted through till the weekend!!
So, I'll just have to go and play squash tonight instead...
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To increase your success rate you might want to consider giving Registax the flick, downloading Deep Sky Stacker and upping the number of darks. 
