The EQ3 DSO Challenge

[mikey2000]

I had significantly better guiding results last night.  My +/-4" (arcsecond) RA swings are down to +/-2" most of the time now.  This makes a big difference!  I had to reduce the ASCOM pulse guide factor (from 0.9 to 0.5) and PHD2 RA aggressiveness.

 

Strangely, I found that using 0.5s guide exposures gave much better results than 2s.  Isn't that against all conventional wisdom?   I quite like the PHD2 'target' graph.  With 0.5s, at least 75% of shots fall within the 2" circle.  At 2s, the number of 4" outliers is vastly increased.

 

Does an EQ3 Pro mount really need guiding every 0.5 s?  It seems so!

 

Anyway, the proof is in the pudding.  After fiddling and tuning, I turned on the camera.  This is after all the whole point!   With the moon shining brightly, I decided on M36 in Auriga.  I was pleasantly surprised to produce nearly-round stars at 1min, 2min and 3min exposures with only one obvious failed sub (I think it's when RA PE has a big spike - I still need to work on PEC....)  9/10 at 60s+ is a major major improvment oveer 5/10 at 45s previously!  I'm very excited to have a clear moonless night soon.....

 

So here is M36.  Very starry and not many colourful stars in that patch.  Approx 15mins, no darks, no flats.  A mix of 1,2 and 3  mins subs all chucked into DSS together.  Nearly the whole frame here (APS-C camera) just cropped a little to shift some horrible stackin artifacts at the edges

 

[wimvb]

Nice result. You'll notice that being able to do 3 minute subs will vastly improve your image quality. Unfortunately DSS seems infamous for sucking the colour out of images. Sometimes it helps to blur a copy of the image and turn saturation all the way up. Use this as the colour information in an LRGB combination.

Thanks for sharing,

[Stub Mandrel]

24 minutes ago, wimvb said:

Nice result. You'll notice that being able to do 3 minute subs will vastly improve your image quality. Unfortunately DSS seems infamous for sucking the colour out of images. Sometimes it helps to blur a copy of the image and turn saturation all the way up. Use this as the colour information in an LRGB combination.

Thanks for sharing,

Hi Wim,

I'm finding some ways to get the best out of DSS, I'm a bit wary of doing a tutorial yet as I'm still discovering things. One trick I use is to manually align the histogram peaks before doing some things to stretch the histogram before saving while the data is still 32 bit. I use this as the starting point for my 'LUM' channel.

I've started going to the 'saturation' tab and increasing it by a modest amount (say 20) and saving a second copy of the data. This second copy responds well to tricks like the 'soft light' approach to increase the saturation more gently.

[Nigel G]

I can't believe how few clear nights we are getting this year.

Wednesday evening was clear but I didn't get home until 8pm so only got an hour of subs on my selected target before it dipped into Basildon & London's light pollution in the Western sky.

So 10 x 360s with 5 dark 20 flat and 50 bias. I intend to get around 15 hours total and a bunch of darks on this to reduce noise and boost the S-N but time is running out.

California nebula with 1 hour exposure. 80ED Pro with flattener & modded 1200d. EQ3 Pro, guided with PHD2, stacked and processed with DSS & Startools.

I keep getting horizontal lines in my images, not sure if is the start of dew forming on the lens. It started when I started using the refractor.

Nige.

[happy-kat]

Do you use a dew shield at all?

[Nigel G]

3 hours ago, happy-kat said:

Do you use a dew shield at all?

Only the scopes extendable dew shield which is around 6 inches long.

I'm looking into making a couple of dew heaters, one for the imaging scope and one for the guide scope.

[wimvb]

I have found that a longer dew shield can be better than a dew heater. My guide scope dew shield extends about 30 cm in front of the lens. Haven't had dew or ice yet, despite not using a dew heater. Otoh, I have had dew and ice when using a heater alone.

[Nigel G]

4 minutes ago, wimvb said:

I have found that a longer dew shield can be better than a dew heater. My guide scope dew shield extends about 30 cm in front of the lens. Haven't had dew or ice yet, despite not using a dew heater. Otoh, I have had dew and ice when using a heater alone.

That's interesting, I will try extending my dew shields first then, I'll add a further 6" to the imaging scope and make one for the guide scope  

Cheers

Nige.

[wimvb]

I don't think the horzontal lines are from dew. Have a look at a single sub and see if the dark lines emanate from bright stars. I have a issue with dark lines like this when stars are becoming over exposed.

http://wimvberlo.blogspot.se/2017/01/correcting-dark-lines-in-dslr-astro.html?m=1

[mikey2000]

Here's a result from an my recent attempt at the Cone Nebula.  Oops. I missed but accidentally discovered Hubble's Variable Nebula.  180s PHD2 guided exposures - almost no problem except for a massive DEC wobble that hit the crossover between two subs, wrecking them totally (excellent zigzag caterpillars in those ones though...)

 

So, I managed 24mins (8x3min).   There was a tiny hint of Cone in the corner but this is cropped away here (the pic below is the centre 1/3 of an APS-C shot).  The Cone was pathetic really;  With a non-modded camera, I probably need several hours of much-longer subs to see it.

 

Anyway, here is a more colourful pic than my one at the top of this page...

[wimvb]

Nice catch. Ha nebs are difficult witj an unmodded camera, the results depend very much on camera make and model. With this target you did very well.

Thanks for sharing

[mikey2000]

Thanks!  I think this nebula (NGC2261) is actually a reflection nebula so not so hard after all.   The Ha nebs will remain most elusive until I splash out on an astromodded camera :-)

[Peco4321]

Here's my latest attempt at the Whirlpool galaxy last night, it was a bit windy and clouds kept rolling in, but I must have had polar alignment and focus really good as I managed 60sec subs and one at 75 sec, ISO 1600, in total only 6 images as it was late, but really pleased with a bit of care I can get this length sub. Stacked with bias frames, no darks or lights in DSS and processed a bit in GIMP. 

[Nova2000]

Nice image. Which lense /scope did you use? 

[Peco4321]

Just now, Nova2000 said:

Nice image. Which lense /scope did you use? 

Sorry, should have said. Skywatcher 150p, canon 1100d at prime focus. 

[Galactic Wanderer]

6 hours ago, Peco4321 said:

Here's my latest attempt at the Whirlpool galaxy last night, it was a bit windy and clouds kept rolling in, but I must have had polar alignment and focus really good as I managed 60sec subs and one at 75 sec, ISO 1600, in total only 6 images as it was late, but really pleased with a bit of care I can get this length sub. Stacked with bias frames, no darks or lights in DSS and processed a bit in GIMP. 

Very good indeed. I imaged M51 for the first time yesterday but I have yet to see the final result!

[Nigel G]

I added a couple of hours to the California neb last night with 33x240s.

This is just the 4 minute subs, next I will add the 10 x 360s subs.

This is also my first process with Pixinsight. There's a lot of modules in PI, if it wasn't for @Filroden and PI tutorials I would be totally lost  

33 x 240s ISO 800 - 10 dark - 30 flat - 50 bias. 80ED Pro - EQ3 Pro - guided. DSS & PI with a tweak in PS.

A ton better than the first.

I think 6 minutes at 800iso is over exposing from my location. The 4 minute subs looked much better.

Cheers

Nige.

Edit-----   240s & 360s 3h 12m image processed with ST added at bottom. Horizontal bars still there, I'm struggling with them, it doesn't appear to be over exposed stars.

 

Edited March 22, 2017 by Nigel G

[Peco4321]

Well this sort of belongs on this thread, 40x 20 sec ISO 3200 darks and bias but no lights, stretched and tinkered with mainly to so show all 3 objects, 2 of which are DSO's. 

[wimvb]

14 minutes ago, Peco4321 said:

Well this sort of belongs on this thread, 40x 20 sec ISO 3200 darks and bias but no lights, stretched and tinkered with mainly to so show all 3 objects, 2 of which are DSO's. 

 

I know that seeing can be bad, but this bad? 

I guess you meant "no flats"

Nice catch, anyway.

Cheers

[StormAurora]

Fantastic! Love it.

 

[Peco4321]

54 minutes ago, wimvb said:

I guess you meant "no flats"

Doh!

[Nova2000]

Nice image! A flat will make it professional

Clear skies 

[mikey2000]

A decent set of flats isn't hard to make and then can really help remove the colour gradients across the pic.  Good to see three DSOs in one phots.  I'm impressed by the whirlpool pics above too.  It's definitely on my list of things to try soon...

[mikey2000]

Here is my first attempt at M101, The Pinwheel Galaxy.  I'd like to gather more data on this one.  It's a decently large DSO for my 150PDS

I had a lot of bad subs this time around (approx 140% failed) but probably my fault - I'm still fiddling with PHD2 settings (and probably making things worse!

12x3mins, 44flat, 20dark and a recycled bias frame.   I cheated a little.  Some of the subs had a bit of streaking in them so I stacked them in anyway to get more on the galaxy.  Then I used the better ones again to make the starfield.  I layered the two results together for a better galaxy combined with better stars.  How much effort!   This is an approx 75% crop of the full shot.

Edited March 24, 2017 by mikey2000
pinwheel, not whirlpool :-)

[Victor Boesen]

7 minutes ago, mikey2000 said:

M101, The Whirlpool Galaxy

pinwheel but very nice picture!!

Edited March 24, 2017 by Victor Boesen