The EQ3 DSO Challenge

[Stub Mandrel]

With a polarscope, I have had 2-minute unguided exposures using a 1200mm scope on my EQ3.

Google 'drift alignment' if you want the best way of aligning without a polarscope.

Neil

[Nova2000]

But isn't drift alignment done with a goto mount? 

[Davey-T]

1 minute ago, Nova2000 said:

But isn't drift alignment done with a goto mount? 

Confusing polar alignment and star alignment I think , drift alignment can be done with any GEM mount.

Dave

[Nova2000]

4 minutes ago, Davey-T said:

Confusing polar alignment and star alignment I think , drift alignment can be done with any GEM mount.

Dave

Yes just Googled it. Will give it a try

[Nova2000]

@Stub Mandrel. 

Which type of eq 3 do you use?  Goto or with ra motor drive? 

[Stub Mandrel]

2 hours ago, Nova2000 said:

@Stub Mandrel. 

Which type of eq 3 do you use?  Goto or with ra motor drive? 

I've made my own goto box with steppers and home-made gearboxes.

[Stub Mandrel]

I got asked for a pictures of my mount, here's a few of the mount. I don't seem to have one of it with the 150PL attached! Also pics of the GOTO box

 

 

 

 

 

 

[bobro]

Wow!!!

[Peco4321]

Here's last nights efforts, not really happy with the Flame, but still enjoyed the session. No flats used so that will be my next mission. 

Flame and a bit of Horsehead Nebula:

135 x 30 sec at ISO 800

50 x bias

 

Whirlpool galaxy:

65 x 20 sec ISO 1600

30 x bias. 

[wimvb]

The whirlpool looks nice. If you can add flat frames, you can improve the vignetting near the corners.

You also caught a nice flame and horsehead. Alnitak and the flame/horse nebulae will always be difficult due to the huge dynamic range of this target. I would be inclined to reduce ISO, because it should give you more dynamic range. ISO is the DSLR equivalent of gain (and offset). Lower gain will generally give more dynamic range and less noise. As long as you stay above the read noise floor, you should be able to stretch the image to compensate for the lower ISO. As always, try to go for the longest single sub exposure that your gear can handle. Adjust ISO to get the best possible trade off between signal and noise/light pollution. If you can collect data for 3 hours in one night with 1 minute exposures, this means that you can collect about 150 frames. Even if you need to throw out 50% of these due to trailing issues, that leaves you with 75 stackable subs.

It usually pays off to investigate time in setting up your scope. Polar alignment, star alignment and balance (with probably an intended off balance to improve tracking) have to be spot on for best results.

Thanks for sharing, and good luck

[Peco4321]

2 hours ago, wimvb said:

you can add flat frames,

So I've been out this afternoon and with the camera on the scope pointing at a cloudy sky, set to AV, I took 30 frames. Is that all I need?  Sorry for ignorance flats are new to me. Can I just keep these for use every time?

 

[happy-kat]

Not really because they become old if you get new dust bunnies anywhere in the train.

[Roysten]

Am enjoying following this thread, some great pics being posted! Got some new kit and got out for the first time in weeks last night. A single sub of everyone's favourite - Orion at 15 seconds with contrast as only post-processing. Rough and ready but a nice demo of what the kit can do.

+1 for the EQ3 mount for DSOs

[wimvb]

That's a nice start. With the weather the way it has been, you may be able to do another sub before it disappears untill next season.

If / when you do manage to add to this, also take flats, bias frames and darks. With some gentle processing, this can become a great image.

Good luck

[mikey2000]

Talking of Everyone's Favourite:  Did  I post this one yet - it was my 'first light' with my EQ3 150PDS.  I managed 14x25s plus some darks and bias.

[Peco4321]

So I added some flats, 30 to be precise, and not sure if much different, please jump in if you think I can do anything else.  I do love this picture anyway, I think this thread, amongst all the great advise, really shows our love of what we can achieve with our modest set ups.  Whilst messing with processing (it is clear outside but I was out last night till gone 02:00!!), I also noticed a load of other galaxies thrown in for free,  I have checked these and  on the 2nd image, from the left they are, NGC5229, IC4278, IC4263 and NGC5169.

 

 

[bobro]

Just finished astromoding my Canon 1000D by removing the IR filter - and have scars to prove it! 

Can't wait for clear skies to try it out - soon I hope!!

[Stub Mandrel]

12 hours ago, Peco4321 said:

So I added some flats, 30 to be precise, and not sure if much different,

The 'index' shot shows there is plenty more detail in your to image to bring out! 'Gradient exterminator' in Photoshop and perhaps Noel's light pollution action would get rid of the patch in the middle. I think you can find more colour too.

Astro pictures are the 'images that keep on giving' :-)

[Stub Mandrel]

12 hours ago, bobro said:

and have scars to prove it!

>ouch<

[wimvb]

13 hours ago, Peco4321 said:

 

It seems to me that you still have a lot of vignetting left, which indicates that your flat calibration isn't working.

Three things that are important when taking flats:

Keep the optical train exactly the same as when shooting light frames. The same camera with the same optics, in the same orientation.

Dust can move around on the sensor, so take flats directly after or before lights. Do not use the sensor clean function of your camera between taking light frames and flat frames.

Exposure should put the main peak of the histogram at or just below the midpoint on the lcd display (dslr). Forget about "adu counts". Flats need to be taken in the linear range of the camera sensor.

An image stacked with flats should have a more evenly distributed background than one stacked without flats (when stretched the same), if your system has vignetting (which most systems do to some extent).

Hope this helps

[Stub Mandrel]

I put the marked up one through gradient exterminator, nothing else...

[bobro]

Thought I'd try to see what GIMP can do by putting the marked up image though it to try and remove the gradient to compare against Gradient Exterminator....

[Nigel G]

17 hours ago, bobro said:

Just finished astromoding my Canon 1000D by removing the IR filter - and have scars to prove it! 

Can't wait for clear skies to try it out - soon I hope!!

It will be worth it, When I done mine I managed to short the main PCB which caused a problem or 2, The new PCB had to be focused to the camera with the hot pixel filter still in place.

In the end it was well worth the head ache.

Good luck.

Nige.

[Peco4321]

2 hours ago, Stub Mandrel said:

 

I put the marked up one through gradient exterminator, nothing else...

 

Thanks, will try messing later to see if I can match your efforts. Cheers. 

[Nigel G]

Well chaps, I am soon going to be posting my own images in here as well as the no EQ challenge.

I have got myself an EQ3 Pro.

Can't wait to use it.

Cheers

Nige.