First night for a lot of things

[andyhicks]

Firstly, WOW!! I was lucky enough to catch the huge fireball everybody is talking about, for all the amazing things I've seen through a scope I think that was, probably, the best thing I've ever seen! amazing!! I caught the whole thing, started as a bright meteor with a green tail then it exploded into glowing, orange fragments. It seemed to last for ages.

OK, just tried autoguiding for the first time! theres nothing complicated about the software is there? I found just getting everything on the mount, plugged in and balanced in the dark was the trickiest part. Here is a picture of my graph..

phd.bmp

On my first attempt it was all over the place and I could only get 60s subs so I re-balanced everything, checked polar alignment and tried again. This is the best I got, what do you think? when I got it to this point and I was ready to take some more test shots my wireless shutter control's battery died but at that point I was distracted by the fireball and lost concentration anyway.

Tonight was an experience! it was my first night setting up dual scope, using the qhy5 and I only got this laptop last night. Imaging was a lot simpler last time I went out! I'll probably need a few sessions to get used to this new way of doing things and for some reason I was trying to do everything in a hurry tonight so Im sure the process will become smoother and hopefully my graph.

Is there anything you can tell me from the graph above? any pointers?

thanks

andy

[Martin-Devon]

Andy - your PHD graph is not that bad at all, especially considering this was your first time with it, I can assure you mine was a lot worse. It's important to have the ST80 bolted down very tight, and the guide camera also firmly in place otherwise you'll rapidly get flexure and wandering images.... There's lot's of threads on using/modifying PHD on SGL, do a search and read up on them, I found them really helpful when I was getting started. Many times you need to tweak the settings - what works for one person's set-up is different for somebody else's. Usually it's the Dec graph that goes for a wander, sometimes called the Dec two-step since it zig-zags in a regular pattern. Making the east side of your balance slightly heavier can sometimes help. But take some credit, you do have the basics of a good first PHD run, and your images will be much better as a result.

[andyhicks]

Thanks for the reply

I've heard about flexure! how many more things do we have to deal with to get good tracking! seems like one thing after another!

I've been building my guide setup for a while and Im now concerned its not upto scratch I'm using a side by side dual mounting bar and the st80 is in adjustable guidescope rings, its secured as tight as I can get it before the screws start to bend the tube. The setup seems solid but now I'm worried its not!

Thanks for the tips, plenty to be thinking about. I forgot to offset the dec balance last night so that might have something to do with the dec corrections in the zig zag pattern? im a little annoyed with myself, I've known about tweaking the balance for ages but just forgot! I had a lot to deal with last night, it was a bit of a farce.

I thought the graph looked a bit hectic but I guess im happy with it. The purpose of last night was just to get things set up and get PHD working so technically it was a success. I was still annoyed when my battery died and i couldnt try it out properly!

I think ill spend the next few practicing dry runs of setting up!

thank you very much for taking a look Martin, much appreciated

[Martin-Devon]

Hi Andy - do your homework as I suggest - but don't get bogged down either with this. Some nights you'll think you have the perfect set-up, everything goes together, and then you get a Rubbish PHD trace! It happens to everybody. The acid test, and one which you must put as highest priority, is what do the star shapes actually look like rather than predicting what they look like. Sometimes a wobbly PHD trace can still give decent star shapes. Also, poor star shapes are not always due to PHD issues either. Polar alignment (PA) is very important, the tighter this is, the less strain is placed on PHD. A good way to test the accuracy of your PA is to do a 5 minute unguided exposure and see the extent of star trails. If they are pretty bad, then you've got poor PA and are not starting from a good position. Get the PA better and everything afterwards will become better. I've recently been using PemPro (free 60 day download) for PA - it looks complicated, but after a few runs is quite straightforward - I can now get 5 minutes unguided exposures with virtually no star trails at all. The other PA software is Alignmaster, which is easier to use and there's an excellent YouTube video that runs through how to use this. There should be no problem with an ST80/CCD guider for PHD - it's a well proven combo, so don't assume that is giving you any issues. I mount mine piggy-back on top of the imaging scope though. I think you're well on your way with an excellent start; it's good to be "picky" as well since this is how you improve, but check the quality of your star shapes and use that as your major readout of what works and what to change. HTH...

[andyhicks]

I quite keen on the alignmaster software, im not using eqmod at the minute though, Im not ready to give up my hand controller just yet! Ill somthat step when im a bit more used to using the laptop with my scope.

I hear what your saying about the proof being in the pudding! im still bothered that I didnt manage to get any test shots with PHD running, so the graph is the only thing I have to go off at the minute. They could have been great for all I know! this leads me to something else you said which is now giving me a feeling of wanting to cry 5 minute subs unguided??!! I WISH! I bought the HEQ5 because I could only gets subs of say, 40 -50 secs out of my vixen GP, now even with the HEQ5 (which I've been using for well over a year) stars start to go eggy at a little over 60secs. Ive set it up so many times and dont really know where im going wrong..?! This applies to my original setup of one scope, things are goind to be different now the setup has changed...

..When I got the mount I aligned the reticule as accurately as I could, its always level and balanced, I use the setting circles for the correct time and date, polaris is placed in the little circle on the reticule and if I rotate around RA polaris tracks perfectly around the larger circle. Ill leave it for a while, come back and tweak it so its as good as I think i can get it and then get imaging. 60 seconds max! so I normally go for 55 sec subs.Thinking about it, for an heq5 this isnt good. Thats why I went for autoguiding!

starting to feel bummed about it all now! I could probably do with a rest, I've done so much reading and learning Im finding it hard to shut off at night and sleep

heres an image I did the other week, 77 - 55sec subs.

I suppose my problem now is why I cant get over 1min unguided?! Im aware the reticule is probably out a bit and id like to use PHD to start drift aligning but i have no southern sky from my yard

I know this is physical hobby not a theoretical one but I need to work out as much as I can as clear nights are rare!

[andyhicks]

Only just got my flat field panel so the flats used on this image were not great and have introduced a sort of mottled background

[Martin-Devon]

Andy - stick at it - we've all been there on the steep learning curve, this is what Astro-imaging is all about. You have a different set-up to me, so difficult to make real comparisons. You use a DSLR whereas I use a CCD. I don't use a polar scope at all, you do. Bear in mind that it's critical your polarscope is calibrated properly - easy to test, put Polaris in the circle and then rotate the RA axis of your mount slowly 360 degrees observing the position of Polaris all the time through the polar scope - it should stay precisely on the larger circle and then end up back inside the bubble again. If not then it is not calibrated properly and you have some work to do. Also, your polar scope is nothing more really than a mini-finder itself, with probably only 25x magnification. So firstly you have to rely on PolarFinder or similar software to know exactly what position to put the bubble of your polar scope at that day/time, and this is all a matter of judgement and error on exactly where you place your bubble, then you've got to put Polaris in the middle - all of this with 25x or therabouts magnification. If you did this on a CCD chip instead there would be huge differences, and you would be much more accurate, so the polar scope is a good but often not perfect first step in polar aligning. I by-pass the polar scope completely by using my CCD chip only, and then polar aligning software either with my Mach-1 mount, or more recently the PemPro or Alignmaster - I think this dramatically more magnified viewing linked to sophisticated polar aligning software should usually give you better and more consistent polar alignment. Again though - run a 5 min (or shorter if you're not confident) unguided exposure to check.

Looks like you & I are the only ones having this conversation as well.... !!

[andyhicks]

Yeah I'm sorry to keep on at you! You were the only one to respond! I realise now my questions are broad and I probably just need to keep practicing!

Just one more thing, you polar align with your ccd... But through what? Your scope? I think I'm going to have to start using eqmod and use software for PA, seems the way to go.

My head is so fried right now I can't even translate what Im trying to say! Time to stop.

Thank you for your time Martin!

[andyhicks]

Sorry! One more thing while I have you. Is it possible to drift align without a southern view? If so then I may have the ability to get good PA as things are now, without spending more money!

Rough polar align (reticule is bang on) ... Use phd to do a drift align..sorted? Right?...

[Martin-Devon]

HI Andy - with the weather forecast this coming week you're going to have a lot of time to relax & think - I doubt many of us are going to be imaging at this rate!

Answering your questions - yes I have my main imaging scope with an Atik 460 CCD, on top of this is a piggy-back mounted ST80 guider/Lodestar for PHD guiding. I do all of my polar aligning through the main scope/Atik 460. For viewing the actual images whilst polar aligning the mount I use the standard Artemis capture software provided by Atik whereas for PemPro I use Maxim capture software (the Artemis will not work with PemPro). This way I get very high sensitivity and accuracy on the stars selected by my polar aligning software. I never image/view on Polaris though for any of this polar aligning - the software picks better star combinations. The PemPro is probably the most advanced polar aligning software you can get - it's a computerized drift alignment method - sometimes referred to as "polar alignment on steroids..." very powerful, a bit fiddly initially (another SGL member Whirlwind very kindly demo'ed this to me, and this helped me a lot), but as I said above once you've done it a couple of times it really is easy to do. You may want to have a shot at Alignmaster first though - even easier! Look at the YouTube video of Alignmaster that I mentioned....

[Martin-Devon]

You second e-mail came through as I was writing back to you - so a little more feedback:

For PemPro you need to be able to get to the equatorial line in the South, or just above it - you don't need to go right down anywhere near the actual South horizon. If your view of the South is blocked badly, stick with Alignmaster - with this you can use stars in the East/West/North if you wish and it works fine.

Yes, start with the polar scope if you want to get you close and then optimize your polar alignment with Alignmaster. Take a 5 minute unguided exposure after each step and see just what difference it makes using the software - should be quite a bit. I've never used PHD though for drift alignment, but I don't see whay you can't just use your ST80/QHY5 linked up to just standard image download mode with a reticle in the - you don't need to run PHD or do a drift alignment at all if you use Aligmaster. This way your ST80/QHY5 would do the same job essentially as my main imaging scope/Atik 460. Just make sure your ST80 is orthogonal though to your Stellarvue triplet scope otherwise some funny things may start to happen - life is a lot easier with a CCD!