Deep Sky Stacker

[dpastern]

Ok, guys, what am I doing wrong? I'm just playing with it, trying to learn how to use it. Apparently, it's easy to use. I must be doing something wrong then. I've taken 2 shots (yes, only 2, just playing) of M8. I've shot them in RAW (CR2) and convered them to 16 bit TIFF files using Canon's DPP. Said TIFF files are in colour. When I open both files in DSS and register/stack them, the result is mono, and has a LOT of noise. Yes, I know I haven't done any flats/darks etc (forgot to last night), but I still feel that the amount of noise being generated by DSS is horrenous. And I can't for the life of me figure out how to get the final stacked shot to appear in colour either. For reference, I've attached a jpg of one of the TIFF shots - if you look closely you can see some colour, but it's a bit harder to spot cos of the resizing etc. I've also included a jpg of the final output of DSS.

Help (please of course)!

Dave

[TheDecepticon]

Deep Sky Stacker will handle your CR2 files. Don't convert your images or anything, just open Deep Sky Stacker and load the images through the open files command. Then look for the recommended settings, select those and check all tabs so you know where you saved it and that is it. Or should be anyway, works for me!!:eyepop:

[leon]

Yep definitly don't convert you images to Tiff, and also just use the defualt setting until you become more experienced.

Leon

[tlgerdes]

Things I have learnt and use with DSS.

1) Reads in CR2 raw files.
2) Stack as Median (default is Average)
3) Align RGB in final Image (Tick on first page of stacking settings)
4) Save final image as 32bit Rational TIFF (defaults to 16bit which gives an almost mono feel to the picture)

[bojan]

After DSS is done, save the file into 16-bit TIFF format, then load this into DPP , play with curves and then convert and save as JPG.
You can have a look at what I am doing, I tried to explain the DPP post processing here (scroll down close to end of page until you see explanation in pictures):
http://www.iceinspace.com.au/forum/showthread.php?t=48651&page=2

EDIT: If by accident you used "Per channel background calibration", this will have "colourless" appearance of the background.. and in LP areas will screw-up the colour balance of the whole image.

EDIT 2:
The noise you see is normal consequence of only two images in a stack.
To have noise visibly reduced, you have to have at least 5 images in stack.. but not more than 20, going above this number there is not much difference, but the processing only takes longer.

[dpastern]

Thanks guys, will play with raw and see what happens. I still don't see why there's so much noise from the stacked pair, especially when noise in the individual images is far less. I'll put it down to my lack of understanding and knowledge on astro imaging ;-)

I only tried a bit of imaging last night because a mate who'd come over said 'go on give it a go'. Since I've had problems with the focuser on the Equinox, I've really lost a lot of the interest that I had in imaging initially. I was pretty happy to be able to focus last night, nay, I was REALLY happy. I'm limited to ten seconds it seems, 15 seconds results in elongated stars due to poor alignment.

Next time I get the scope out, I'm going to give it a try again.

Dave

[renormalised]

What's happening with the focuser??. Too much play in the draw tube?? You may need a better focuser assembly, or you can tighten the one you have up a bit to make it a little more robust.

[dpastern]

mmm no go for this lad. Stacked image has less details than the actual RAW files themselves. I'll double check the settings later in DSS, maybe I still have something set wrong.

Thanks for all the help guys, much appreciated.

Dave

[dpastern]

It just simply won't grip properly if the OTA is pointing even remotely upwards. Even with a 2" eyepiece (no camera). My mate noticed it last night. You basically have to put pressure on the bottom of the 2" diagonal as you're trying to focus in order for it to grab. I've tried tightening etc, does S.F.A. I was so surprised that it focused last night with the camera on. The last time I tried, it only not only refused to come to focus witih the camera on, but when I took the camera off and put the diagonal and eyepiece back on, I couldn't gain focus with it either. I can only think that the internal focusing unit is damaged. I prolly should return it to Andrews, especially since I raised it as an issue within 2 months of buying the unit.

Dave

[renormalised]

If it's still under warranty, I would return it. If not and you're still having problems I would get a replacement. A good Moonlite or Feathertouch focuser would be spicky.

[dpastern]

Yeah, it's under warranty. I'll PM you my thoughts in private.

Dave

[bojan]

I do not think so.
Try to increase the contrast of the individual CR2 image to the same extent as a stacked image and you will see it contains LESS noise.

The important thing to remember is that the S/N (Signal to Noise ratio) is what we are talking about here and what we are increasing by stacking a number of individual frames into a single image.

[tlgerdes]

Bojan is right, what you are trying to do by stacking is increase the signal to noise ratio. By only having 2 light frames and no dark frames, you havent really accomplished that in any major way.

The Deep Sky Stacker website has a good explaination on the why and how http://deepskystacker.free.fr/english/theory.htm

As it says in the opening lines.
Why combine?
The answer is simple: only to increase the Signal to Noise Ratio (SNR).
Is the resulting image more luminous? No.
Is the resulting image more colorful? No.

The goal of combing many images into one is only to increase the SNR. The resulting images are neither more luminous or more colorful but they contain much less noise which will let you stretch the histogram a lot more which will give you more freedom to bring back colors and details.

[dpastern]

Thanks Trevor - I did read that bit in the FAQ/help file actually, but it didn't make sense to me at the time. Despite a busy day @ work and feeling tired from it all, it sunk in just now. :-)

Dave

PS you still doing ciscos etc? My bosses are wanting me to learn them...I'd be happy to if I actually had the time @ work lol

[dpastern]

If it's clear on the weekend, I'm going to give it another crack at M8 and try and get 30 or so 10 second subs. Hopefully I'll get something out of it that's usable. I'll try and remember darks and flats as well. Thanks again everyone for your advice.

Dave

[Octane]

Dave,

Don't forget flat darks, too! :)

Regards,
Humayun

[dpastern]

Oh now I'm confused...more research required by moi.

Dave

[Octane]

Dave,

Nooo, don't be confused! The easiest way to think about it is to treat your flat frames just like light frames. You take darks for lights, so take equal length exposures for your flat lights.

Some people will tell you to take bias or offset frames to remove sensor readout noise (1/4000 or 1/8000 second exposures, the shortest your camera can do), but, in my experience they tend to ruin or add artefacting to my images. I also figure that the bias is also recorded in the dark frame, so, shouldn't really need it. Might work for others, just not for me!

Hope that helps.

Regards,
Humayun

[bojan]

David, do not worry about Darks and flats for the beginning.
Just play with DSS stacking to obtain the feeling of what it does.

As for darks, they are just exposures of the same duration taken with lens cap on.
If you set your camera to aumatically compensate for long exposures (this will be on special functions menu, Long exposure noise reduction), the camera will take darks for you and do all necessary math on image file.
So you just carry on with stacking.
However, this method (LNR) is inferior to taking separate darks and stacking them in DSS (it is more noisy).

Taking Flats are very easy task, but perhaps not necessary at the beginning. They will compensate for so called "vignetting" which is un-even illumination of image frame (lighter in the centre, darker at edges).

[dpastern]

I'm going to do a bit more research and reading on this on Saturday during the day.

Just one question - if I'm going to do darks, should I turn off the noise reduction in my camera?

Dave

[bojan]

Yes.

There are couple of reasons for taking separate darks:
- Taking separate darks and stacking them in DSS results in slightly better SNR for the same number of stacked frames.
- LNR takes twice the time (for example, if you are taking 30 sec exposures (lights), camera will take another 30 sec for LNR compensation for each frame).

Please note, you should take the same exposure time for darks. But it can be done later, and you do not have to take as many darks as lights. Some people will say you should take the same number but this is not my experience). They should be taken at same temperature, though.. best immediately after your photo session.

[Octane]

Dave,

Yes, absolutely, turn off ICNR.

Regards,
Humayun

[dpastern]

You guys rock! It's one of the reasons why, despite me being a grumble bum sometimes, I really like IIS and its community.

Dave

[Barrykgerdes]

Theoretically each sub should have a dark and a flat taken at the same time, added to each before stacking. This will usually ensure that the camera and chip errors can be cancelled out as accurately as possible leaving only the picture and the noise in the sub. In practice this is usually not necessary as has already been said and described.

Then as the noise is random stacking will increase the picture level much more than the noise thus improving the S/N ratio and consequently allow more latitude in processing the final picture.

Barry

[dpastern]

It's making sense to this lad. Slowly. I guess, even if I only get 10 second subs due to poor polar alignment, I should be able to take *lots* of subs, darks, flats etc and still get some half decent images. The amount of data is really then going to be up to me, and how prepared I am to get the necessary amount of subs. I'd love 5 min subs, but alas, without a permanent observatory, it's not really feasible imho. Especially since due to either poor weather, or just simply being too tired, my scope time is limited. I love Astronomy, and I really want to do more imaging, hence asking these "silly" questions.

Thanks Barry. It's a pity I never got to sit down and talk to you about it all when I lived with Warren & Ange.

Dave

[dpastern]

OK, I had a crack at M8 last night - 23 data shots @ 6 secs apiece (to limit star trailing). 5 darks, 1 flat. Better than nothing. The battery on my camera was near dead, so this limited me. I assembled everything in DSS, and it kept 18 files. FWHM was around 3 for most images, which is probably pretty good for manual focus I suspect. The resultant tif (around 35mb) can be found here:

http://www.ecn.net.au/~dpastern/m8.tif

I'm not quite sure how to best approach post processing of this in Photoshop. I tried some work with levels, but whilst it revealed details, it introduced a LOT of noise and colours were not right.

Any suggestions?

Dave

[bojan]

Hmmm
Something is not right here.
I opened your file in DSS, and re-saved it as 16-bit tiff, to be able to process it in DPP.
There are some artefacts present to the right of each brighter star (black dots) and the noise is almost as if the stacking did not take place at all.
Maybe you did not follow the DSS procedure correctly?

To stack, you need to just click on "register checked pictures".
Make sure all is checked, and darks and flats are loaded as such (upper part of the left-side menu).
Otherwise I do not know what went wrong here.. but something did, and badly.

And, yes, do not do any curves in DSS... it is painfully slow so it is very hard to control the process

[bojan]

Actually, when I think of it, the image is pretty good, considering you took 6 sec exposures only.
The noise came from stretching.
You really need longer exposures..
However I can not explain those black artefacts.
The colours may be wrong because of light pollution? Where did you take those pictures from?

Just to give you a reference, the attached image was taken from my backyard last year, with MTO1100-A (1100mm, F11) lens, 30 sec at ISO1600.
It is a stack of 8 exposures.

[tlgerdes]

I think your big problem here is still S/N ratio.

23 data shots @ 6 secs apiece (to limit star trailing). 5 darks, 1 flat.

I dont think you are getting enough signal to overcome the inherrent noise.

When I do 8 sec shots I can't pull a clean picture out. I have to go to at least 30sec subs to get a decent S/N ratio to pull a clean picture.

What sort of mount/scope are you using to only limit you to 6 secs.

I take it you are only tracking and not guiding.

[dpastern]

Thanks guys. You are probably right - not enough data.

Trevor - I'm using a Equinox 100ED + EQ6PRO mount. Since I don't have a permanent setup, nor an ability to have one (long story short my parents property is in about the worst possible shape/position/location possible), I'm having to setup every time. At this point I am not doing an accurate polar align, I'll try this via the drift align method when I get a Reticular eyepiece with about 90x mag. That should hopefully allow some longer subs then.

I'm shooting from suburbia Brissie - Ipswich. So, LP is an issue. The Mark IIn camera is older as well, so noise at ISO 1600 is quite bad, especially when compared to newer cameras like the 5D Mark II.

Bojan - I have a sneaking suspicion that the black artifacts are from DSS trying to remove hotspots from my camera's sensor. Again, I'm very unhappy with Canon in this respect - my Mark IIn has probably 100+ hot pixels even with Six second exposures. It's not normal and is not within spec I believe and is disgraceful QA from Canon.

I'm to the point where after being a Canon user for 20 odd years I'm going to give them the finger and switch to Nikon. Far better cameras imho.

Dave

[bojan]

Wait a moment before switching to Nikon..

Read here first: http://www.astrosurf.com/buil/50d/test.htm

BTW, my image was taken with Canon 400D.
And it was done with the lens mounted on EQ6, no guiding, polar aligned with provided polar scope. I have roughly 70% good frames with 30 sec exposure (the rest show trails due to PE and noise in gears).

As to removal of hot pixels, this is accomplished by darks. So you should un-check the removal of hot pixels feature in DSS.
However, I do not think this is the reason for black artefacts... it is almost as if the negative image was superimposed onto the rest, but shifted (most likely due to a bad polar alignment).

[tlgerdes]

Hi Dave,

At least to start with, just take longer exposures to get some data to play with. Then you can work on alignment later.

Alternatively, go wider in field, screw your camera onto the top of the OTA and take shots through a normal lense (50-100mm). You could then easily go out to about a minute with out too much alignment error and start capturing some real/better data.

[dpastern]

Yes, it could be slight movement of the frame I guess during the period that I took the shots, and then, I guess misalignment in DSS. I've seen similar things using CombineZM for my macro shots.

As to Nikon, photography is a major hobby of mine (terrestial). Astro imaging with a DSLR is only a minor interest for me, if I'm going to get serious with astro imaging I'll need a permanent mount setup, accurate polar align, better mount, dedicated imaging camera. Nikon's D3 is far better than anything Canon offers at the moment. And truth be told, I'm rather jaded with Canon over a variety of issues, and exceptionally poor customer service that I've received in the past. I won't go into it in detail, since I'll be labelled a "Canon basher" like I have on POTN.

I do NOT believe in giving praise to a bad manufacturer.

Dave

[MrB]

David, you are using an early 5D mkII?
I think Canon addressed this black dot issue:

http://www.google.com.au/search?source=ig&hl=en&rlz=1G1GGLQ_ENAU340&=&q=canon+black+dot+problem&btnG=Google+Search&meta=lr%3D&aq=f&oq=

[toryglen-boy]

Hi Dave

i used to get subs of about 2 mins tops, before i was autoguiding, so getting a more percise alignment will allow you to get some good shots, and 10 or so 2min subs stacked with DSS will produce a nice image.

While stacking images will improve the SNR and make detail easier to see, at the end of the day, there is no real substitute for exposure, and you shoul do some tests to see how far you can push your subs.

stick at it though !!

;)

[bojan]

!!!!!!!!!!!!!!!!

But this surely does not apply to RAW format.. or does it?

If it does, then CMOS sensor has a problem.. how that can be solved by new firmware (and preserving the original data)?

[Octane]

He is using a 1D Mark IIN, not a 5D Mark II.

I have one of the first cameras to land in the country and do not suffer from the black dot problem or banding or anything else. I haven't even upgraded my firmware.

I have not received a single complaint from any of my clients that I've photographed at weddings or portrait sessions. Look at the landscape work I have posted. Do the images suffer from noise or image degradation? The A3+ prints are staggering in detail and quality. This comment is not leveled at David (as I know he knows how to take a photograph and process it, his macro work is a testament to that), or anyone in particular, but, you have to draw the line somewhere - stop pixel peeping and get back to the art. A lot of people who do nothing but pixel peep can't take a photo to save themselves. I see it all the time on DP Review. What good is it b*tching about the technology if you can't even photograph properly?

Dave, if Nikon makes you happy, go for it. I'm sorry you feel the way you feel about your gear. Do remember, though, that technology improves drastically with time. Your camera is getting on a bit now. Despite it being professional gear, let's not kid ourselves, it will pale in SNR performance of the newer cameras. I love my Canon gear as it performs flawlessly for me. If you have L-series glass for sale, I'm interested. ;)

Regards,
Humayun

[dpastern]

No, I'm using an older 1D Mark IIn ;-) the black dot syndrome not only affected the 5D mark II, but also older cameras as well. dpreview.com had countless threads on the subject!

Dave

[bojan]

Mate, it is not about b*itching here, it is about correct data record.
I personally do not care about art.. For me the camera is a photometric equipment, and all I care is whether my astro images contain real data I can measure and not artefacts, which are not data.
Of course, if I were in art, I would not mind black dot here and there.. it may even be regarded as an expression of "artistic freedom" :P

[dpastern]

Thanks Duncan - at the moment I'm limited to between 5 and 10 second subs without any drift alignment it seems. Frustrating to say the least. I eventually will get a reticular eyepiece and will learn drift alignment to get better subs, I know it's the best way of approaching this, I'm just trying to hack things "as is" for the moment! Thanks for the encouragement.

Humayun - I know newer Canons are better in noise etc, but my problems require a bit of background history to see where I'm coming from.

1. A very bad experience with Canon Australia re: 1D batteries and a 430ex flash unit and offshoe adaptor. Worst customer service I've encountered in 30 years of being a consumer.

2. I seem to have bought a "dud" 1D Mark IIn, at least in many ways. Far too many hot pixels for a 6 second exposure imho, firewire port died too. True, I bought it 2nd hand, but unit was only 9 months old when I bought it, one owner. I'd expect a 6k pro camera to be made better, and have better QA.

3. Canon refuse to provide 64 bit drivers for FireWire connectibility for the Mark II/n. I'm tempting to take legal action over this, as I believe that they are in breach of several areas of the Trade Practices Act 1974, or at least it's legally open to interpretation. Whilst the Act states that manufacturers are legally obliged to provide spare parts and support for a product for 5 years from date of cessation of the product being part of the current range, I believe that drivers, especially in todays modern products, should be included in this. With things like a camera, the driver is CRITICAL for the product to interface with the computer.

True, I can use a memory card reader, but each time I use that, I run the potential risk of either damaging the card, or the pins in the camera's card slot. As you can appreciate, using a firewire cable from camera to PC is far less risky from that perspective.

Canon simply is being lazy, and tighta$$es by not producing drivers. I'm not saying Nikon is any better in this respect btw. I don't believe in rewarding manufacturers for bad support.

There, I've said my bit.

Dave

[toryglen-boy]

Dave, if you dont drift align, then you can get very good aligment with a compass, an inclinometre, and some info of the net.

I dont drift align, my mount was setup using the above equipment, and i can do exposures over 30 mins without trailing.

:)

[bojan]

Yes.
And as I mentioned before, you can align even better with build-in polar finder (just make sure it is properly adjusted, this can be done during the day on a distant tree, for example - adjust the reticle until the central cross is placed at the detail which does not move as you rotate the shaft).

I placed three concrete slabs (10x10cm) in the loan, with shallow holes for tripod legs.
This way, I do not have to align every time I go out, once in a week is good enough (provided I do not dismantle the tripod after session, of course).

Of course, drift alignment will give you better results, but it takes time, which is sometimes valuable...

[dpastern]

The problem is the land that my parents house is on - from the backyard I have no views of the South, and none of the East. Limited of the West. North is pretty much OK. Positioning the scope on the East/West of the property doesn't help. That leaves setting up the scope on the front section of the property. As the front is shallow, and steep, and as either trees or houses block views to the east/west (although not as bad as from the backyard), I'm limited to a very small area to place the scope and get some semblance of view. Sadly, the best place is not on our property, but just off it, on council property. So I can't set up anything permanently there. I can move the scope/tripod 2 metres back from this semi ideal spot, but alas, I start to lose views to the east/west (north/south are still OK). It's a really bad situation and I can't do much with it. It pretty much kills a permanent mount setup imho.

I do need to get a inclinometer and I have measured due South due to solar noon. It's no longer marked, but I could probably permanently mark it somehow. I know I need to get longer subs.

Of course, I'm not even to the point of guiding yet, but that, also, will come in the future.

I think the first step is to get an electronic inclinometer and work on getting due south better. And also a reticular eyepiece and get drift alignment going. Then I should be able to get 5 min subs at least!

Bojan - I'm not sure what you mean by aligning with the built in polar finder during the day. How can I do that when the stars won't be visible to align against, or am I completely misunderstanding you?

Dave

[bojan]

The problem is, polar scope is usually not aligned at the factory (that was my case as well).
What I did was, I pointed the polar shaft of my EQ6 mount to a distant roof (20-30 metres away) , so that the top was near the centre of the FOV of the polar scope.
Then, by rotating the shaft by 90 degrees back and forth, and adjusting it left-right and up-down, I directed the axis exactly on the top point of that roof.
The next step was to adjust the cross of the reticle to coincide with that point of the roof.
If you are doing this you have to be careful with reticle, it is easily damaged if the grab screws are tightened too much. Also, there are three screws - not very convenient for adjustment (it would have been much better if there were 4) but it is possible to do, and it has to be done only once.
Then you can use polar scope when you are away from home, it is pretty accurate - I do not have problem at all with 1 minute exposures. The bigger problem will be periodic error in the main worm gear.

For the compass, I mounted it on the 0.5m long Al rod, which can be screwed onto and removed easily from the mount RA shaft . For Melbourne, the difference between true South (North) direction and what needle is showing is 11 degrees to the west, so this has to be taken into account. Once adjusted, you leave compass alone on that rod for the next session
And of course, you should make use of the build-in bubble level (it comes with newer mounts, if yours does not have one, you should definitely place it on the RA shaft, and it should be adjustable. you should null it when you have RA shaft pointed exactly (or near enough) at SCP.
This way, you have to align your mount only once. Next time only bubble level and compass are enough, even if you go somewhere out of the city.
However, if you go couple of hundred kilometres to the South or North from your home, you should check the elevation or RA shaft, the difference in elevation will abe significant and quite visible in the polar finder (and on your photographs as well)

[dpastern]

Thanks for the explanation, much appreciated. I'll have to look at the polar scope during the daytime - many have said not to bother with it because of the lack of a bright star around the South celestial pole. I like your idea with the compass on a long shaft - that's brilliant. I think most of my problem is probably due to innacurate latitude adjustments. An inclinometer will resolve that problem.

I'm gradually getting things together - at the moment and for the next Six months, my main goal is a car. After that, I'll do some stuff with the astro gear :) :) :) :)

My goal is to to learn drift aligning, get accurate polar align, 5 min subs and guiding going. After that, it's mastering darks, flats, lights etc. And after that, PP. I'm not worried if it takes me a few years, or even if I don't master it all, as long as I'm having fun, that's all that matters. And despite a rought early start with imaging, I'm having fun!

Dave

[Octane]

Dave,

It's a hard slog, but, keep at it. You'll often wonder why you bother. Then, you'll start dozing off at work daydreaming about the next time you get a chance to image and what you will be imaging and what the weather will be like and whether your equipment will conspire against you, etc. This is one nasty and obsessive hobby! :P

Keep at it!

Regards,
Humayun

[dpastern]

I already do that lol!

Dave

[TheDecepticon]

Hello, what is DPP?:)

[Octane]

Canon's Digital Photo Professional.

Regards,
Humayun

[TheDecepticon]

Sorry to butt in, didn't want to start a new thread.
When I stack an image in DSS and choose to Autosave the resulting file, it is in a 32bit HDR file. How do I save a normal 16bit file?

[bojan]

Click "Save Picture to file" then choose 16-bit tiff.

[TheDecepticon]

DOH! That easy.:rolleyes:

[gbeal]

OK, having read the thread from top to bottom I'll stay out of the camera suitability debate.
I started with Nikons, went to Canon, and have now settled on Sony. Why? C'os most of my DSLR shots are during the day and I like the Zeiss lenses Sony use. Nothing more or less.
Dave, I reckon you are seriously into self abuse here. The root problem stems from the lack of polar alignment and really you need to sort this. Of the semi-serious astrosnappers on this forum I would venture to suggest only a small amount of the have a set-up which approaches a permanent one, and that includes me. I roll mine in and out each night I use it. The trick is to reduce the effort, I am lazy in this respect. Get yourself an area where you can safely say you will be able to image most or all of the time. Get set up and don't image, POLAR ALIGN. Once it is correct, or better, ensure that you can return to the same spot every time, and simply "plonk it down". In my case I have levelling screws on my rolling pier and these are screwed down each time I use it, (to lift the pier off the wheels). The points of these screws/bolts are tapered and fit into three large stainless steel washers glued to the asphalt surface where I image.
If you need help with polar aligning, get it, there are gazzilions of members who likely live close and would be happy to help you.
Then you will notice the whole things gets easier.
Gary

[dpastern]

Yeah, I know Gary, and it's good advice. Once I get a reticular eyepiece, I'm going to work on polar alignment and drift alignment etc. I know it needs working on. And I know that imaging will improve once I get it all down to pat.

Dave

[gbeal]

Cheers Dave, I was afraid you may have taken offence. But in the end, it starts with alignment, and works outward from there.
See if you can get some help with the polar alignment, and get the marks set out on the ground so the repeatability is there as well. Then start thinking about longer exposures. Get some help from anyone who will assist. If you are really stuck I can even lend you a reticule eyepiece, if that is all that is holding you back.
Gary

[dpastern]

no no no no, takes more than that to offend me for starters, and your post wasn't even remotely offensive. It's all good advice and I appreciate it.

Reticule will happen in the next 5 weeks. From there I'm going to work on polar alignment etc. As you said, practice and things will be good. I'm going to be getting an electronic inclinometer as well. Don't worry, it'll happen.

I guess I was hoping I could still do half decent shots in the interim. I can't wait for M42 to come around again, cos I'm pretty sure I'll be able to better my first efforts (3 x 30 second shots stacked in DSS). I'm sure 40 or 50 10 second shots will be a lot better! And this time around, darks and flats as well. Go me.

Dave

Dave

[bojan]

Dave, I do not think more of shorter shots will be much better..
There is no need to take much more than 10-15 shots.. but it helps a lot if they are longer.

As for reticule, why don't you try to improvise something in the meantime?
Actually, you do not need it, your camera with some software (for example, Crosshair.exe by Joe Smith.. or Al's http://www.iceinspace.com.au/forum/showthread.php?t=21798 crosshair) will be quite adequate, in combination with camera control application which downloads and displays image on the screen ( Focus assist works with Canon, I am not sure if it works with Nikon, http://www.dslrfocus.com/, there was a freeware version available).
There are some methods described elsewhere on IIS, but all of them basically follow drift alignment method: You are taking images of the same star every couple of minutes, with the help of screen crosshair you see where the star is drifting, and you adjust the polar axis up or down, left or right until there is no drift.
When this is done, you simply start imaging.
And, do not forget other advice here, particularly those related to repeatability of your setup.. Someone hammered into the soil three 1/2" waterpipes 15-20cm long , and the EQ mount legs are supposed just to be inserted into those pipes.. repeatability is more than adequate, provided you do not dismantle the tripod.

EDIT:
I just checked, http://www.xmission.com/~jstanley/focusassist/ (http://www.xmission.com/%7Ejstanley/focusassist/) FocusAssist does not work with Nikon.. only some Canon models :-(

[gbeal]

Ah, spot on Bojan, Dave, try the likes of K3 CCD Tools, and a webcam, it has the Ponder Polar Align Routine built in. And there are others, all of which utilise a webcam instead of the reticule.
If pictures of the "repeatability" side of my setup will help, just ask.
Gary

[bojan]

I found the post with water pipes..
http://www.iceinspace.com.au/forum/showthread.php?t=35041
As far as my semi-permanent site is concerned, instead of those plastic pads shown on images and/or pipes, now I have concrete slabs (~10cm cubes)

Gary,what did you do?

[dpastern]

Interesting. Very interesting. You know, I'm tempted to move only as far back as possible and get a permanent pier setup, just far back enough to be on our land and not on council land. Must give it some thought long term wise.

I won't bother with a webcam - initial goal is a 10mm reticule etc, drift align with that, get polar align pretty well spot on or as close as, then image. If I can get 2-3 min subs without star drift, and not having to guide, so much the better. Guiding will come later on down the track. Still thinking about getting an of axis guider, or separate guide scope/autoguider (leaning towards the latter).

Dave

[Tandum]

I still have this piece of pipe if you want it.

http://www.iceinspace.com.au/forum/showthread.php?t=45707

[gbeal]

Bojan.
the end of each leg terminates in a wheel slightly inboard, and a levelling screw on the extreme end, mine being M12 bolts, with a taper/point on the lower end (knob on the top).
I got the mount roughly polar aligned without worrying about being perfect, and also got it level (built in bubble).
Then used locking nuts to secure the amount that each screws down, and at the same time glued stainless steel washers onto the asphalt where I use the mount every time. The taper/points fit within the central hole of the S/S washers. Simple.
Gary

[dpastern]

That is a very nice offer. I have no idea where Carindale is (sorry, long term Sydneyite lol) and rely on public transport (at least until I get a car, which is next on my list).

Dave

[bojan]

Here it is what I have now.
I use it for both mounts (EQ6 and EQ3) I have..
The only adjustment to check is bubble level. The rest is pre-adjusted (by drift method, using my Canon camera and 500mm mirror lens and laptop.