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Messages - dtrewren

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Hi Guys,

Apologies for the delay in replying, been on a short holiday - well if you consider a children's theme park a holiday !

Great feedback thanks.  Jason I applied your blur + saturate technique and really like the result.  Takes the hard edge off the stars making them look more natural and the saturation really brings them out  ...... definitely a tweak i'll be using in the future !

Cheers & clear skies,


DSO's CCD Color / Re: M51 - Whirlpool Galaxy in HaLRGB
« on: April 15, 2012, 11:51:24 AM »
Really fantastic image C&T, such a fantastic target and executed beautifully  :good:

Clear skies,


DSO's CCD Color / Re: M81 & M82 another from West UK
« on: April 07, 2012, 03:20:07 AM »
Thanks for the positive feedback guys !

Yes Craig the QHY9M still working fine.  I seem to have a bad column in there but using Sander Pool's fixfits can easily get rid of it and also clear up any hot pixels at the same time.

Cheers & clear skies,


Hi Craig,

Very much appreciate the feedback - cheers !

Yes I process the luminance & RGB completely separately.  I start with luminance, stretching using IP4.5 DDP.  Then transfer luminance to Photoshop for maybe a touch more selective stretching using curves.  Then use layer masking to perform localized sharpening.  Noise control using NC actions and sometimes very gentle Noise Ninja.  RGB processed separately with a touch of Gaussian blur.  Once combined tend to do as little as possible to keep the noise down. 

I think I could get more by stretching more but I personally I really don't like process noise and would rather back off a little detail to keep control of the noise.

It's a steep curve and no mistake :)

Clear skies,


Hello Guys,

I have just finished processing my crack at the Leo Triplet.  I know it's an old favourite but it's a personal first for me so thought I would share and see what people think.  Taken a few attempts to get off first base with this mono camera LRGB business but now really enjoying it.

Image on my web space :

Details on link at base of image.

Hope you like, feedback always very welcome and valued !

Cheers & clear skies,


DSO's CCD Color / Re: M81 & M82 another from West UK
« on: April 06, 2012, 12:05:05 PM »
Thanks Jason & Bill,

Very pleased you like the image - we did get a window of a few days when the cloud departed and some decent imaging could take place.  There is nothing better than having some new data to process :)

Cheers & clear skies,


DSO's CCD Color / Re: M81 & M82 another from West UK
« on: April 06, 2012, 03:29:18 AM »
Hi Ben, Les & Mike,

Thank you very much for checking out the image and the feedback, much appreciated :)

I love this target and always find it great fun to image !

Have a good Easter.

Clear skies,


DSO's CCD Color / M81 & M82 another from West UK
« on: April 05, 2012, 06:51:31 PM »
Hello fellow imagers,

After being a spot busy with project work and general tinkering I finally got around to processing some data captured during a lovely week we had recently here in the UK.  I thought I would start with M81 & M82 just because I find their pairing particularly pleasing to the eye and fun to process.

Here is the image on my web space :

I hope you like the image, as always comments much appreciated.

Cheers & clear skies,


DSO's CCD Color / Re: M51 - LHaRGB from UK West coast
« on: March 19, 2012, 11:08:02 AM »
Hi Bill,

Cheers, thanks for the feedback !

Hopefully, get out tonight if this weather holds - never stays clear for long here :)

Clear skies,


DSO's CCD Color / Re: M51 - LHaRGB from UK West coast
« on: March 16, 2012, 03:43:52 AM »
Hi Dave,

Cool, thanks for the feedback - much appreciated :)

I'll send more photos when (if) the fog ever lifts.  I'm not going to send any nice
girls from Nottingham should I happen upon one  :lol:

Cheers & clear skies,


Hi Bill & David,

Excellent, really pleased you like the wide field look for the Cone  !

The wide field rig was fun to build.  I need to spray the base up nice and matt black, left the plastic coating on for these photos so you can see the focuser gear better.  The focusing works well, having a belt drive pulley one side and an idler the other removes any lateral force on the lens and the belt acts to support the lens.  As luck would have it the teeth on the belt exactly match the lens focus barrel grip indentations resulting in no chance at all of any slip.  The aluminium drive and idler pulleys are mounted on 3mm stainless steel shafts in turn supported by aluminium pillow bearings to reduce the friction to a minimum, the stepper motor appears to cope just fine.

Getting the dew buster straps on was interesting  ;)

Cheers & clear skies (not in the UK),


Hi Eric,

I have posted on the ImagesPlus web site and UKAI.  Craig suggested I post here as it might be of interest on ECA.  I just posted a bit more detail on the DIY section.

Going to be creating  a new web space very soon showing the PCB implementation

I am the other way around, not really done a great deal of Basic.  The PIC firmware is written in C and the driver code and GUI written in Visual C#.

Sure, that's the motivation for doing and posting projects is to learn and also share information so any questions fire away.  I have learnt loads of stuff about imaging, processing and optics from guys out there so figured I could put something back.

Clear skies,


DIY / SharpSky ASCOM compliant digital focuser project
« on: March 09, 2012, 05:20:12 PM »
Hello East Coast Astro,

I have posted this project on a couple of other forums but thought it might be of interest here ...

I have designed an ASCOM compliant cost effective telescope focuser with the following features :

-  Low cost
-  Simple construction based around an
   off the shelf PIC micro
-  Bootloader for simple USB firmware upgrade
   (no dedicated programmer required)
-  ASCOM compliant
-  Absolute positioning
-  Temperature compensation and profile logging
-  USB connectivity
-  Manual scope side focus control
-  Variable manual rate
-  Stepper motor mechanical drive

The current design shown on the website uses a PIC microprocessor development card.  However, things have moved on a little since then.  The cost of the development cards went up a bit so I decided to design a dedicated PCB board married with suitable case.  The PCB's have been fabricated and are expect next week.  The PCB makes the whole design much easier to build, more compact and inherently reliable.  All of the connectors are now PCB mounted and the motor connection is Moonlite/Robo compatible.  Quite a number of people have build the development card based design which has been very useful as feedback has allowed me to refine the PC ASCOM driver and PIC embedded firmware to be compatible with main stream client software such as ImagesPlus, MaximDL, APT, SharpCap ... well anything ASCOM compliant.  So far the design has been tested successfully with MaximDL in an autofocus mode of operation.  As soon as I get a PCB built up and tested I'll generated another web space to demonstrate.

The design is fully up and running and fitted to both my refractors.  I have put together a website detailing the design for anyone interested :

Main site showing the design in kit form with dedicated PCB :

Site, showing development board implementation :

I have now added temperature compensation & logging functionality  :

I am not running a company or business - just hobby fun  :dance1:

Hope you fined it interesting, any questions or comments please fire away !

Cheers & clear skies,


Hi Eric,

My Epoxy is curing, so I will post the focuser design on the DIY section :)


Hello Eric,

Me, too I really like wide field views too, I find the the entire scene humbling !

I was about to post my SharpSky focuser project on the DIY section as Craig suggested.  I am just fitting a dimmer power supply to my EL panel for doing flats so will post proper once the supply is complete and working.

Here are the links to the project website :

Link to the temperature compensation enhancement :

I have just completed PCB's for the project, expected next week - very excited about that  !!!

Will post proper in DIY once this PSU has been tamed  :yes:

Clear skies,


Hello Fellow Imagers,

Here I am posting an image of the Cone Nebula on a very widefield canvas.  The image was taken with the following setup :

- Lens, Nikkor 180mm f/2.8 ED  (shot taken at f/4)
- Imaging camera QHY9M + FW
- Guidescope, modified 8x50 + Starshoot AG
- Mount HEQ5
- Filter Baader Ha
- Focusing SharpSky (self design)

Image : 1200s x 11 subs + darks

In order to achieve the widefield view I coupled the Nikkor lens to the QHY9M camera/FW combination.  The Nikkor lens (as do all Nikon lenses) has a back focus of 46.5mm.  In order to give the motorised focus system some headroom I positioned the sensor at 45.5mm resulting in about 3/4 of barrel turn before hitting the lens end stop.  In the images (see link) the lens is focused at infinity and it can be seen that there still focusing headroom as the lens is not at it's end stop.

Here is a link to the image :

Here is a link to a few images of the gear :

I love the Nikkor lens as it is excellent at f2/8 and exceptional at f/4 producing a very flat field without the need for any additional field flattening.  I have attached the result of the field curvature analysis.

Cheers & clear skies from the UK,


DSO's CCD Color / Re: M51 - LHaRGB from UK West coast
« on: March 09, 2012, 10:54:11 AM »
Hi Craig,

Finally got around to posting images on ECA having joined 'ages' ago.  Wanted to get a couple/three ok images together before getting in my dinghy and paddling down the Severn and then out over the pond.

Ok, no problem - if you think guys would be interested in a spot of project work and tinkering I'll post some links  :)

Cloudy here, hope your skies are clear ....


Cheers  Jason,

It was seeing the Veil imaged by Craig & Tammy that motivated me to move from DSLR imaging to CCD mono imaging using NB.  When I saw their image, it was so amazing I just had to have a go !

I think it will be one of those targets I never get bored of imaging - a truly fantastic structure !

Clear skies,


DSO's CCD Color / Re: M51 - LHaRGB from UK West coast
« on: March 09, 2012, 09:50:19 AM »
Hi Mike,

Appreciate the feedback, I wasn't to sure how far to push the localized sharpening and thought I might have overcooked it a wee bit.  I was pleasantly surprised at how much Ha data came from M51.  There is an all weather football pitch about 1/4 mile from my site (as if the LP wasn't bad enough) while waiting for the lads to kill the flood lights thought I'd grab some Ha - lucky call as it helped the image.  Which image processing software tends to be flavour of the day in the US ?  I tend to use ImagesPlus and Photoshop.

Les : I love the Scrumpy - but unfortunately ... it makes you blind, destroys the following day and sends you mad :)

DSO's CCD Color / Re: M51 - LHaRGB from UK West coast
« on: March 09, 2012, 09:14:39 AM »
Hi Eric,

Thanks for the thumbs up on M51 & the Veil Nebula NB image I posted !!!

Weather wise ...... I think from an imaging point of view your are much better off in the Texan desert !

I think if I could have your desert and our West country cider it would be heaven  :yes:

Clear skies,


DSO's CCD Color / Re: M51 - LHaRGB from UK West coast
« on: March 09, 2012, 09:08:05 AM »
Hello Derek,

It amazes me to sometimes !

I just have to drop everything and head out whenever I can.  Clear nights are few and far between so when it's clear everything stops and I get out for as long as it stays clear.  If it means staying up all night to catch the weather then I take a half day off work and sleep in (they understand ... sort of).  Narrowband has helped because it means the moon is less of and issue and so there are around a third more potentially clear nights per season.  Also the NB seems to cut through the haze and high cloud.

At the end of the day, if I get a few half decent images at the end of the season I'm a happy bunny !



Narrowband and HST Palette Imaging / Veil Nebula in NB - Bristol, UK
« on: March 09, 2012, 08:57:20 AM »
Hi Guys,

Really like the NB images in this section so thought I'd post one of mine from the other side of the pond.  I was motivated last year to save my pennies and buy a cooled mono camera + FW.  After lots of head scratching I decided on the QHY9M as the best setup I could get for the cash available.

I have been really pleased with the camera so far and NB imaging has almost completely solved my upsetting light pollution issue.  Here I have posted the Veil Nebula, my first attempt at NB last year.

Link to imaging  :

The imaging details are on the link at the base of the image.

Cheers & clear skies from the UK,


DSO's CCD Color / Re: M51 - LHaRGB from UK West coast
« on: March 09, 2012, 08:43:41 AM »
Ah yes,

Kielder is proper up North, that's where they have a popular star party.  It is very dark, checked it out on a
light pollution map.  Dark, but probably rains quite a bit :)  saying that being over in the West we get our fair
share of rain - if Ireland doesn't get it we are next in line !

I expect you guys in the US get your own problems with heat & humidity (and maybe night bugs) ?



DSO's CCD Color / Re: M51 - LHaRGB from UK West coast
« on: March 09, 2012, 08:28:09 AM »
Hello Les,

Thank you for the feedback, pleased you like the image :)

I am located just outside Bristol in the South West.  A bit too close to Bristol to be honest, so do suffer
from the dreaded light pollution.

I have been imaging mainly in narrowband this season since investing in a cooled mono camera + FW.  I
really like the East Coast Astro layout with the imaging sections (mono, NB,  colour CCD ...) all nicely defined.
Makes browsing images a very nice experience.

I'll pop one or two narrowband images in the relevant area and see what you guys think.

Hoping for some clear skies soon !


DSO's CCD Color / Re: M51 - LHaRGB from UK West coast
« on: March 09, 2012, 06:42:39 AM »
Hi Jason,

Thank you for the welcome and your feedback !

I have been looking at all the other images in the various categories - some amazing work.  You guys over the pond have been busy  :good:

Regards & clear skies,


DSO's CCD Color / M51 - LHaRGB from UK West coast
« on: March 09, 2012, 04:18:16 AM »
Hello Fellow Imagers,

This is my first post on East Coast Astro - I'm actually in the UK and on the West coast but, just a technicality :)

I am posting my interpretation of M51 which I captured last Sunday.  The moon was out and there was the usual UK haze but I thought I would give it a go.  In order to add a bit more interest I captured some Ha data and added into the Red channel.  Quite pleased with the result, on reflection may have over sharpened the dust lanes a tad.

Main image in my web-space :

Details regarding the imaging can be found on the link at the foot of the image.

Hope you like, comments always very welcome .....

Cheers & clear skies,


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