bobro

Wow!!!

You were spot on Wim! The clouds cleared for a bit tonight, allowing just 7 lights at 8 minutes (plus flats). Using your suggestion of processing a greyscale image and doing an lrgb blend ('value' in GIMP) made for a much better image. Of course more lights will improve it but I'm more than happy with what my simple EQ2 setup has produced so far. A great learning exercise too. Thanks! Bob

Thanks for the tip Wim - I will look into MT. For now I tried using layers to extract the stars before GIMP processing. Had some success though my effort looks a bit artificial. Practice, practice......

Not much chance of taking more lights of the Rosette Nebula due to the weather, so had another go at processing the 12 lights previously captured - a little better. Lots of stars - will need to practice toning them down in order to better see the nebula (when I get more lights!).

First attempt at the Rosette Nebula - just about recognisable. Quite a gusty evening - limited length and number of exposures that were usable. In the end just 12 lights of 4 min at IS01600. Next time...

Below is a simple stack - 3 off 10 minutes subs (lights only) at ISO1600 as a test. I hope to image the California Nebula but wonder if 10 minute subs is perhaps a bit too much and that 5 minutes may be better to aim for. Advice appreciated.

I was put off trying astrophotography a few years back after purchasing a book with the subtitle of 'Astrophotography with Affordable Equipment and Software' - the cost of the setup was horrendous!! It was only by chance last year that I came across a Meade 130 plus motor drive from Currys at £150 - made me think again. What a stroke of luck that was. I have enjoyed my initial attempts so much and am probably becoming a bit of an astrophotography bore - just have to tell everyone! My basic setup (with simple mods) cost : Scope and 1st RA motor £150, guidescope £85, guide camera (webcam) £30, 2nd motor £30, Raspberry PI £35, Canon 1000D (used) £85, various cables etc £40. In all, not a lot of expense. The often quoted advice to buy an EQ5 to get into astrophotogrqaphy is of course a solid one - you can't go wrong with an EQ5. But not everyone can afford it and some of us just like pushing the boundaries and learning with something a bit simpler (and lower cost). We don't start off understanding what will interest us e.g. I initially though it a bit strange not to look through a telescope and thought imaging the Pleiades wouldn't be interesting enough - but it is! And I don't look through my scope and more (sorry observing people). So I vote for including a low cost way into imaging to let people try it out. Note that doesn't necessarily mean easy - it can be easier to spend more and get results with less effort. Depends what suits. To finish my beginner's rant, I have to add a beginner's M42 of course - a mix of 10 and 45 second exposures to try and stop the core oversaturating. (DSS and GIMP 2.9.x processing.)

Hope EQ2 imagers can post here too ! Couple of ISO1600 images at 2 minute exposures from a beginning imager. EQ3 stuff is far too expensive!

To complete this post, below is my first attempt at imaging (Flame Nebula) with guiding provided by RA motors for both RA and DEC guiding on the EQ2 - an unusual guiding setup as the motors are not stepper motors. As long as there is no wind, stars are round (ignoring coma). With wind comes some movement, so work is needed in that direction. Need to work on image processing too .

Perhaps DIYers will be interested in a low cost guiding setup for EQ2 mounts. I'm not sure if this approach has been tried before, but it's relatively straightforward to implement and is certainly low cost. In early 2016 I purchased a Meade Polaris 130 scope, complete with EQ2 mount and Economy RA (clockwork) motor drive with the intention of trying out astrophotography at a low entry cost. Very quickly the prime focus problem arose - so the scope was shortened by 40mm. With this mod 30 second exposures very not too difficult, with 60 seconds sometimes successful. Of course the problem was tracking. Rather than spend time taking lots of 30 second exposures and knowing that longer exposures were really the way forward, I decided to investigate the Economy RA Motor to see if it could be modified in some way for guiding. The answer soon became apparent - yes it could (with very simple mods) but I had no idea how well it would work. Next steps were to look for a way to guide the motor - an Orion mini guide scope and Microsoft Cinema webcam (modified of course) plus a Raspberry PI with Lin_guider were relatively painless to get going and the results were good. However, DEC drift could still cause star trails, so a bit of thought came up with the idea of using an Economy RA Motor as a DEC motor, again to be controlled by the Raspberry PI. This evening the setup was given its for test for dual axis guiding (5 min RA guiding had been successful previously). Not the best sky - very bright due to the moon and clouds appearing. Still, taking no time for polar alignment other than to point the scope slightly to one side of the pole star, a guide star was found, guiding started, guiding gain etc adjusted and a couple of images taken before the clouds got in the way. Results - no doubt as seasoned astrophotographers would expect, DEC guiding just needs a bit of correcting from time to time - the gain of Lin_guider had to be brought down to stop oscillation. RA guiding takes much more frequent corrections, again with a low gain for my setup. My aim with the mods was to see if such a low cost and basic setup could be made to guide - also at a low cost and with simple equipment/mods. On the face of things it is not too involved and I hope that it will be useful to those who don't want to jump into the expense of more mainstream equipment. It could also be a low cost learning curve into guided astrophotography for those who have already purchased a scope with EQ2 mount. Next steps for me is to find (hopefully!) some clear skies for a chance at decent imaging. Weight hasn't been added to the mount as yet - this should improve stability although the short 650mm focal length is a help when it comes to stability and guiding errors. Below is a 5 minute (bright) single image taken this evening with dual axis guiding (at 100 ASA due to the moon). The central star seems reasonably round, though coma affects other stars towards the edge of the image. I've also attached diagrams of the setup and another earlier 5 minute single image taken with RA only guiding.

That's correct - the guiding software (lin_guider) runs on the PI. The laptop is purely a remote desktop to the PI in my setup. Guiding normally requires some pretty heavy maths e.g. https://en.wikipedia.org/wiki/PID_controller You can find out more about lin_guider at : http://rpm.pbone.net/index.php3/stat/45/idpl/18820081/numer/1/nazwa/lin_guider Nice use of the PI camera to capture the moon (that's how I initially tested out my Microsoft Cinema webcam). Perhaps it could be a useful guide camera? Good luck with the projects!

Glad you find the PI guiding interesting adder. Of course I am more than happy to share the mods and setup with anyone interested. Here is a diagram and also a photo of the just added DEC motor (actually a modified Economy RA motor) waiting for a PI relay board to arrive for test. You can find more photos at http://guiding.web.fastmail.co.uk/ and I can post any other info required to this web location. Thanks for the interest. Bob

Thanks DP and D4N for the useful advice. I can see now that my Meade 130 suffers from coma, though no plan to deal with that as yet. It's taken me a while to respond as I've been trying out what you suggested amongst getting to know my setup better. The scope is better balanced and the RA motor faster/slower directions more equal than they were before. Unfortunately my guidescope/webcam combination couldn't capture enough stars for Sharpcap to help with polar alignment. Instead I've been using drift alignment, with the camera outputting bi-directional star trails for viewing on my laptop. It's a bit fiddly to adjust azimuth on my EQ2 - but it works in the end. So far, my guiding setup is working better than I had hoped. Below is an example of a 5 minute single image (IMG_0007 - captured at 400 ASA as it was early and the sky was bright). My experience with DSS is going downhill - very bright final stacked image and very little colour, so I decided to try manual stacking with GIMP - see the Pleiades image below (2 minute exposures so not too difficult as high in the sky where RA movements are slower). GIMP is labour intensive though, so I will possibly need to look for another program if I don't have much success with DSS (have tried both raw and jpeg images - same results). Any suggestions anyone? When guiding, DEC gently drifts north and south before finally going off the guiding screen as errors mount up - this can show up on the captured image. So I plan to add DEC guiding to the mount - using a 2nd (modified) economy RA motor connected in place of the DEC cable control, with the Raspberry PI guiding. Hopefully I will then be able to see what the setup can do as far as imaging does, before adding suggested weight to the mount as necessary for stability. Do you think the DEC motor guiding will improve the image, or is backlash likely to be a problem? Many thanks.

My itch to try astrophotography was 'scratched' earlier this year with the purchase of a Meade Polaris 130 reflector, complete with economy ('clockwork') RA motor drive. It has been fun trying to image with a Canon EOS 1000D - 30 second images are generally OK, plus the occasional 60 second success. The RA economy motor is a drawback to longer exposures due to the difficulty in setting the speed with a tiny dial and no real speed control as the dc motor is simply driven by a variable voltage. Rather than upgrade the motor drive, I decided to see if it could be made to guide, adding to the Meade scope an Orion 50mm mini guide scope, Microsoft Cinema webcam (as a guide camera) and a Raspberry PI running Lin_guider software. The PI drives a relay board, sending faster/slower signals to the RA motor drive, with just a single resistor mod to the motor drive for remote control. It wasn't the best evening for a test of the setup, but the clouds finally parted, allowing the test to go ahead. The initial result - yes it worked! The relays clicked away, keeping the RA on track. The amplitude of the guiding swings looked quite large, especially when dew clouded the guide camera! There's a lot of tinkering to do to understand and adjust the various guide parameters. The load is at the limit of what the EQ2 mount can carry (4kg), so it might struggle a bit. It looks as though the scope doesn't have a parabolic mirror, so star shapes aren't great towards the image edges. I need to work on polar alignment as there was Dec drift. Nevertheless, an interesting (and very low cost) start into guided imaging - can't wait for more clear skies. Below is the first guided image - 12 stacked lights of 2 minutes at 1600ASA. I expected to see a bit more colour - overdid it in the processing to make it 'interesting'. Can someone tell me why so little colour? Any suggestions on (simple) improvements to the setup or the best way to achieve polar alignment would be helpful (I wondered about using SharpCap 2.9 for polar alignment but I don't think the Microsoft Cinema webcam will be sensitive enough). Many thanks.