Cheapskate Astrophotography

[jimbo747]

Being a tight git, I like to push the limits of cheap, nasty and unsuitable equipment. I'm also limited to about 20-30 minutes in a session at night due to young kids, so a heq5 and triplet would be wasted on me.

First clear night in weeks last night, so thought I'd give first light to my newly purchased and currently unmodded canon 1100d, and my newly purchased celestron travelscope 70mm from ebay. I used my celestron SLT alt az goto mount that came with my mak. This is my 2nd ever DSO image after taking m42 with a ps3 web cam.

As it was just a test to see what could be achieved with the above. I wasn't expecting anything other than a blurry CA infected image, but I was quite surprised. M67 was chosen as my scope happened to be pointing that way after aligning. It was quite low in the east and test photos would have allowed over a minute, but as it was rising I shorted exposures to allow for longer tracking.  I only stacked 13mins worth (20 x 40s) and took 25 subs in total - all looked equal in 'quality' for want of a better word.

Some CA and tracking error is obviously evident, and if I had any photoshop skills other than the curves tool I could probably do a bit more with it. 

The image is cropped down quite a bit.

Cost of my equipment

Celestron 70mm Travel scope £30

Canon 1100d £70 (broken auto focus apparently)

SLT Alt az mount (was new with Mak scope, probably around £150 on ebay)

Will mod the camera over the coming weeks if cloudy and try some other targets, and add them to this thread.

[Astrosurf]

Not bad! Just try again with shorter subs or higher ISO. what Settings were you using, by the way?

Alexxx

[jimbo747]

Beos was set to 1600. You think the subs were too long then? Wanted to try and get some colour in the stars, there are hints of yellows and whites but I didn't want to process the colour in as that would be faking it! (or is that what the pro's do!)

The camera and mount gives a bit of shake when the mirror bangs about, is there any way of stopping this from within Beos or is there some sort of physical mod I can do? I put some delays in but don't think it made a difference.

[Astrosurf]

I use the mirror lock-up setting. That helps. Are you using a remote shutter release? They're invaluable!

Maybe the trailling is caused by camera shake, so try again with mirror lock-up (if you have that option) and use a programmable remote shutter release. I also set my camera to delay for a couple of seconds before the pic is taken to minimise wobble.

[jgs001]

Nicely done.

Nothing wrong with the little SLT mount for imaging, if you set it up right, and accept the limitations. You want to get the balance right... slightly tail heavy, i.e. the weight biased towards the camera. Not a lot, just enough to keep the gears engaged, or it'll bounce around all over the place. Keep the max exposure time down dependant on where in the sky you're imaging... Low in the east/west is good for up to 2 minutes (well beyond the drive limitations, I was losing 50% subs with 2 minute exposures due to tracking errors), down to 30 seconds, North/South and overhead. I would also suggest using mirror lockup, with the self timer in bulb mode with some form of intervalometer (cheap clones on amazon and ebay can be had for about £12). I used to use an ST80 clone on a NexStar SLT for DSO's, and managed to get the bubble nebula with an unmodded camera.

[jimbo747]

I'm pretty sure I set the mirror lock to '2' but as soon as it made a noise the exposure timer started counting - I was expecting a pause of 2 seconds before it started exposure. Does Beos not take the place of a remote shutter (never used a DSLR until the other night so not really any idea how these things work!)

jgs - I think the slt mount with the really light travelscope makes a good match as the DSLR makes it slightly tail heavy.

[jgs001]

You need to set the mirror lockup to enable it, then also set the camera self timer. The effect is, that when the exposure is triggered, the mirror lifts, the self timer activates, and once the self timer has counted down, the shutter opens. Add the couple of seconds that the self timer uses to the exposure plan in ByeOS. 

As long as the skew in balance is small, that's ok, but make sure that the tail isn't too heavy, and thus puts undue strain on the mount. You may need to shift the scope forwards to counter the excess weight, I don't know how the travelscope is mounted in this case.

[jgs001]

Jim, you might want to take a look at http://stargazerslounge.com/topic/228101-the-no-eq-dso-challenge/ for examples of what are possible.

[jimbo747]

Thanks, I'll have a look. Hoping for a clear night tonight, last night clouded pretty quickly after 9.00pm round here.

Quick question, will an unmodded camera image galaxies just as well as a modded camera? I was under the impression it was mainly nebula that benefited and made little difference to most clusters.

[jgs001]

That's pretty much correct... an unmodded camera is less sensitive to infrared (Hydrogen Alpha emissions). Thus images of the likes of M42 tend to be much bluer with an unmodded camera, than with a modded camera. (My M42 image in that thread is an exception, but that's down to the CA filter I was using stripping out the blue). 

The biggest problem with galaxies, and this is where an SLR becomes less than ideal, they mostly, appear pretty small in the FOV, and the large sensor of an SLR means they appear small in the frame, unless you have a really long focal length. There's no way with an SLT. That doesn't mean you can't get some results on the like of M31 though. So give it a go, just go against the grain and wait until it's low in the east... you can get longer exposures that way.

[LukeSkywatcher]

I like this. Its not perfect but its a great start (i'd be happy with it). Time and time again here on SGL many members have shown that AP can be done very well with cheap gear and unorthodox methods. 

The main thing is that you have fun doing it and are happy (or even half way happy) with the results. My hat is off to people who find cheap but effective ways of doing astronomy.

Well done. Now just fine tune your focus and tracking (and cut down on exposure times) and that image will be a belter.

[jimbo747]

Thanks, the focuser on the travel scope isn't very good, I won't moan about my mak ever again!

If wind dies down I might try m44 tonight and try and get an hours worth of 30s or so. The north and south are pretty much blocked from my garden so can only shoot objects in the E or W or directly overhead.

Jgs "no way with an SLT" - sounds like a challenge to me! Might try with the mak and see what happens.

[jgs001]

What's wrong the focuser ? If it's 'sloppy' and loose, then Teflon tape will cure that.

It's not a challenge, I tried all sorts with my SLT. Upgrsding my scope from an ST80 to an ED80 caused me enough problems with the SLT.

I tried with a mak on my heq5, and the Make was just to slow (f/13) for an SLR. Good luck if you want to give it a try.

Sent from my GT-I9300 using Tapatalk

[jimbo747]

The focuser is just really tight so turning it makes the whole mount twist - when trying to focus on jupiter in BEOS it just flies offscreen! Also as the knob is big its hard to do it accurately.

Anyway I tried to do some imaging of m44 beehive last night and while I took about 45 mins worth, the majority were ruined by the wind. Shame as it was quite clear and enjoyed playing with the binoculars. Could do with a wind break or something. Even so, here it is.

30x 30s stacked (I used less exposure as suggested above). The stars look very blue, mainly due to CA but from looking at other images most in the cluster seem to have a blue or orange tinge so left them as it.

5 x darks

Not as pleased with it as my first image but it goes in the bank.

[Astrosurf]

What processing sw are you using??

[jimbo747]

Photoshop CS2.

If you've got some tips and pointers I'm all ears! I pretty much just used the curves tool to bring out some detail and tried to use a mask to reduce the star trails from the wind (found a tutorial this morning). I'm in no way an expert in it although with naff data there is only so much you can do anyway.

[Astrosurf]

I'm desperately trying to remember what I do in RGB as I've been processing Ha in StarTools lately!

I check Levels first to see if there's any space before the left-hand (black) side. If so, I bring the black slider over to just before the curve and move the right (white) slider up to the black line, if there's any empty space there. I do two or three iterations, then I start on Curves. My only warning is keep an eye on the stars to make sure they're not getting overblown!

What I do is make a copy of the unprocessed image and work on the copy, just in case I mess up. I also use Adjustment layers so I can alter them at a later date if I need to. To prevent build-up of layers, I occasionally make a master layer of them all by clicking on the topmost layer and using the Ctrl+Shift+Alt+E key commands (I hope that's right!). I use the Magic Wand tool to select the stars to stop them from blowing out. With stars selected, I use the Select > Modify > Expand then Select > Modify > Feather tool to ensure the whole of the stars are selected and the selection softened. Don't push the stretching too far with the stars selected as you'll get a dark ring around the stars. (I've tried using a Star Mask but I've never had have much luck.) I re-do the star selections periodically with subtle changes in selection size. 

I also find it helps to reduce star bloat by bringing the white point in Curves down a tad to the right hand side of the graph, which reduces the stars' brightness a bit.

You can also do Filter > Other > Minimum > e.g. 1, with selected stars, to reduce their size.

I wish I could remember properly!

[jimbo747]

Thank you for that! I'll have a play with some of my images to practice with. I'll try that with the levels tool - wasn't sure what I was doing with that before but your post makes it clearer, thank you.

[Astrosurf]

You're welcome! Let us know how you get on.

[damnut]

Thats a cracking start, there was a tutorial in S@N  a while ago about histogram stretching, but if you google it you will find some tutorials, Also there are loads of astro plugins for CS2, again you goggle you will find them . There was also a previous thread on SGL :--  http://stargazerslounge.com/topic/180893-photoshop-astrophotography-plug-ins/

[happy-kat]

I think you could take a look at astronomy shed youtube video on fine tuning the ST80. I imagine that your focuser will have very small adjustment screws/allen key fittings that can be used to either tighten our loosen the focuser. I don't think yours should be so right it causes wobbles.

My camera 1100d does not have mirror lock up either and in my 30 second exposures some have been perfect so I don't think trails are that from the mirror slap.

Keep going and working on the sweet spot :-)

[RichM63]

Just chimming in to offer support. I understand the joys and tribulations of trying to 'make a silk purse out of a sow's ear'.

Focusing is my current Nemesis with either the ST80 or Samyang as camera lenses. Tip for ST80 type, (clothes peg on one of the focus knobs to provide a larger hand/knob ratio, thus increased sensitivity over a smaller movement).

[jimbo747]

To help with my focusing issues, and in continuing the theme of imaging on the cheap, I bought a new motorised focuser for the grand sum of £18 inc delivery from ebay.

http://www.ebay.co.uk/itm/171737891395

Should fit the travelscope and perhaps with some jiggery pokery fit the mak scope too.

[jimbo747]

Managed to do a bit of imaging (about 15 minutes worth!) the other night, so tried another cluster I quite liked the look of - m53. Thought I'd use this thread again.

I tried a bit more processing in CS2 but overdone it I reckon, focus was off again so tried the technique described above. Yet to fit my electric focuser or mod the 1100d, kids for you.

14 minutes of 30s exposures stacked from a 20m session.

[cuivenion]

Keep up the good work Jimbo!