The "No EQ" DSO Challenge!

[Filroden]

29 minutes ago, Yamez said:

Fantastic image, may i ask how you managed 5 minutes in an alt-az?

It's five minutes of 1 second exposures, so 300 subs being stacked.

[Nigel G]

28 minutes ago, Yamez said:

Fantastic image, may i ask how you managed 5 minutes in an alt-az?

I believe it's 1 second exposures and 5 minutes of each rgb

Nige.

[Yamez]

oh yeah my bad, i misread the post. I need to catch up on some sleep 

[MattJenko]

Yes, I used Sharpcap to capture a 10min video of 1 sec exposures for each channel and used the best 300 frames from each (half) when aligning/stacking.

The gradient top right is actually because I had to take the Red on a different night than the others and I was about 45 degrees rotated when I did the others!

Edited November 7, 2016 by MattJenko

[parallaxerr]

Hi everyone,

Good to see the thread's still going strong and getting far too technical for my brain! I've been out of it for a few weeks with illness and a back injury, boo.

Anyway, decided to get back to it tonight, I was planning to add to my M31 data only to find out it's now too high in the sky for my mount.

So...next target is M33. Also having toyed with the idea for a while I've decided to give the ST120 a shot, see if I can't capture a few more photons per sub! I couldn't use the St120 for M33, it wouldn't get it all in but no problem for the smaller targets. Really interested to see how the Baader MPCC works in a different scope - the ST120 is closer to the midpoint of the recommended focal ratio range so should be OK.

My ST already has a Moonlite fitted so the camera is hanging well, but I struggled with focusing a bit, the CA made it a little more tricky so may invest in a bahtinov mask.

Anyway, here it is in all it's glory. Results should be interesting although I'm not getting my hopes too high due to the moon glow and random left over fireworks!

 

Edited November 7, 2016 by parallaxerr

[Victor Boesen]

23 minutes ago, parallaxerr said:

Hi everyone,

Good to see the thread's still going strong and getting far too technical for my brain! I've been out of it for a few weeks with illness and a back injury, boo.

Anyway, decided to get back to it tonight, I was planning to add to my M31 data only to find out it's now too high in the sky for my mount.

So...next target is M33. Also having toyed with the idea for a while I've decided to give the ST120 a shot, see if I can't capture a few more photons per sub! I couldn't use the St120 for M33, it wouldn't get it all in but no problem for the smaller targets. Really interested to see how the Baader MPCC works in a different scope - the ST120 is closer to the midpoint of the recommended focal ratio range so should be OK.

My ST already has a Moonlite fitted so the camera is hanging well, but I struggled with focusing a bit, the CA made it a little more tricky so may invest in a bahtinov mask.

Anyway, here it is in all it's glory. Results should be interesting although I'm not getting my hopes too high due to the moon glow and random left over fireworks!

 

Excited to see what you can manage to get. Good luck from here!!

Victor Boesen

[Filroden]

25 minutes ago, parallaxerr said:

Hi everyone,

Good to see the thread's still going strong and getting far too technical for my brain! I've been out of it for a few weeks with illness and a back injury, boo.

Anyway, decided to get back to it tonight, I was planning to add to my M31 data only to find out it's now too high in the sky for my mount.

So...next target is M33. Also having toyed with the idea for a while I've decided to give the ST120 a shot, see if I can't capture a few more photons per sub! I couldn't use the St120 for M33, it wouldn't get it all in but no problem for the smaller targets. Really interested to see how the Baader MPCC works in a different scope - the ST120 is closer to the midpoint of the recommended focal ratio range so should be OK.

My ST already has a Moonlite fitted so the camera is hanging well, but I struggled with focusing a bit, the CA made it a little more tricky so may invest in a bahtinov mask.

Anyway, here it is in all it's glory. Results should be interesting although I'm not getting my hopes too high due to the moon glow and random left over fireworks!

I couldn't manage without the Bahtinov mask. It makes things to much easier and quicker. I once tried the focus aid for the mask in SharpCap but found I was just as accurate and much quicker doing it by eye. I'd find focus, move out of focus and then back into focus (just to make sure). Moon glow shouldn't be too bad for another day or two? It sets in another 2 hours so plenty of targets far enough away! Good luck tonight.

[jimbo747]

1 hour ago, Yamez said:

Fantastic image, may i ask how you managed 5 minutes in an alt-az?

1s exposures.

I've got my mak and guide scope setup. Annoyingly I still can't get nexremote to launch with a virtual port - just crashes so can't use stellarium.

Focused it earlier this evening, logged in to team viewer just now and may need to adjust focus on the mak before using it in anger. I've got the 224mc connected to the mak, may add my focal reducer to it while I'm at it. Moon disappearing soon, forecast clear, can't wait. No doubt something will go wrong...

 

Edit - jesus I'm a slow typer, about 10 posts appeared!

 

Edited November 7, 2016 by jimbo747

[SteveNickolls]

1 hour ago, parallaxerr said:

so may invest in a bahtinov mask.

A mask will make focusing that much simpler. Good luck imaging. The equipment looks good :-)

Cheers,
Steve

[jimbo747]

57 minutes ago, SteveNickolls said:

A mask will make focusing that much simpler. Good luck imaging. The equipment looks good :-)

Cheers,
Steve

Think I need one. Focusing at a focal length of 15 in the cold with laptop in one hand, knob in the other isn't easy.

 

Only on SGL could you get away with that sentence...

[The Admiral]

14 hours ago, MattJenko said:

Reprocessed AltAz M15. 5 mins each RGB channel in 1 sec exposures.

 

A nice rendition there Matt. That's one advantage of imaging stars, they don't need such lengthy total exposures, and by keeping the sub exposure times short you run less risk of saturating them (though of course that will be more of a problem with DSLRs).

Ian

[parallaxerr]

1 hour ago, The Admiral said:

That's one advantage of imaging stars, they don't need such lengthy total exposures, and by keeping the sub exposure times short you run less risk of saturating them (though of course that will be more of a problem with DSLRs).

I learnt this last night! After imaging M33 I slewed to Pleiades as it's one of my favourite visual targets, however, I left the exposure set at 30s. Result = Big bloaty blue (with the achro) stars!

[parallaxerr]

Update on last nights trial with the ST120:

I gathered about 150, 30s exposures of M33 along with 50 darks. Inspecting the light frames shows that the Baader MPCC works even better with the faster F5 ST than the F5.9 WO ZS66, I see no coma at all in the corners I had managed to get a reasonable focus but not perfect, so I've just ordered a mask.

The CA isn't as bad as I thought. Obviously the fainter the target the better I suppose? It was heavy on Pleiades as noted above but that was just a rush job with bad settings.

Being impatient as I am, I stacked the M33 frames up in DSS just to see what was there. No flats or darks flats yet, so there was some noticeable vignetting. I'll be doing them tonight and re-stacking.

The main issue is horrendous light pollution though, such a horrible orange noise to the image. The longer nights may mean I can get out earlier but I'm thinking there's not much point starting until gone midnight when the streetlamps go out and the neighbours go to bed! But, work and the nursery run dictate that I can't be doing that really.

Did I read somewhere recently that someone has had good results with an LP filter? I have a 1.25" Baader Semi-Apo which I found VERY effetive in the ST for visual. As I understand, it "overlays a slightly more aggressive version of the fringe killer coatings onto the neodymium substrate of the Moon & sky-glow filter" so I wonder if the 2" version may suit for AP?

[Filroden]

48 minutes ago, parallaxerr said:

I learnt this last night! After imaging M33 I slewed to Pleiades as it's one of my favourite visual targets, however, I left the exposure set at 30s. Result = Big bloaty blue (with the achro) stars!

You shouldn't be getting that much bloat in 30s. For targets with very bright areas you might want to try reducing the ISO as this should give you greater dynamic range but there is a danger that you lose the feinter signal into the read noise (in this case, the nebulosity). My own image of M45 used 30s subs (only 30 in total) and it gave a pleasing enough image of the stars and showed the nebulosity. I'm using a CMOS camera though it is cooled and has a very low read noise. However, I was using a very high gain (equivalent to ISO) so had a limited dynamic range. So a DSLR should be able to cope.

[MattJenko]

another advantage of 1 second subs is that it negates the effect of seeing to a certain extent. it is not quite in the realm of fast frame rate high res planetary imaging, but it is getting there. I reckon a bigger aperture than my 10", like a driven 16" dob+, you could do bright targets with 0.5 sec subs and then you could really start pushing towards the actual theoretical limits of the optics, not limited by the seeing.

[Filroden]

12 minutes ago, parallaxerr said:

The main issue is horrendous light pollution though, such a horrible orange noise to the image. The longer nights may mean I can get out earlier but I'm thinking there's not much point starting until gone midnight when the streetlamps go out and the neighbours go to bed! But, work and the nursery run dictate that I can't be doing that really.

Did I read somewhere recently that someone has had good results with an LP filter? I have a 1.25" Baader Semi-Apo which I found VERY effetive in the ST for visual. As I understand, it "overlays a slightly more aggressive version of the fringe killer coatings onto the neodymium substrate of the Moon & sky-glow filter" so I wonder if the 2" version may suit for AP?

If you can't image late, then try for targets above 30 dec to avoid the worst of it. You can remove much of the gradient in tools like Photoshop (GradientXTerminator), StarTools (wipe) and Pixinsight (ABE and DBE) but it does mean you need your target signal to exceed the light pollution. Again, for bright objects like M33 this should not be a problem, it just adds processing complexity. Only the moon tends to be bright enough to make me not image at all. LP only limits my choice (and time) of targets.

Nige has recently be testing a LP filter and his results so far look very good.

[Filroden]

2 minutes ago, MattJenko said:

another advantage of 1 second subs is that it negates the effect of seeing to a certain extent. it is not quite in the realm of fast frame rate high res planetary imaging, but it is getting there. I reckon a bigger aperture than my 10", like a driven 16" dob+, you could do bright targets with 0.5 sec subs and then you could really start pushing towards the actual theoretical limits of the optics, not limited by the seeing.

Also, cameras with very low read noise under dark skies could get you to faster exposure times. I think my ZWO ASI1600 can manage 24fps at max resolution (though I'm not sure my USB connection can handle the data traffic). Though this is now in the realms of video astronomy.

Edited November 8, 2016 by Filroden

[parallaxerr]

3 minutes ago, Filroden said:

for bright objects like M33 this should not be a problem, it just adds processing complexity

I think you hit the nail on the head here Fil, I really need to get my head into Startools some more!

[alacant]

17 minutes ago, Filroden said:

Big bloaty blue (with the achro) stars

Hi. I find modern achros good for AP. You may want to get one of these which prevents invisible radiation being recorded by the sensor. HTH.

[parallaxerr]

I've had a look back through the thread for posts about filters and came across two posts of interest.

@SteveNickolls, you mention using the semi-apo, have you tried it yet? I rate the 1.25" one I have highly for visual and am considereing the 2" for AP.

@Nigel G, you've had some success with an LP filter, can I ask which one you are using?

Thanks both.

Edited November 8, 2016 by parallaxerr

[parallaxerr]

1 minute ago, alacant said:

Hi. I find modern achros good for AP. You may want to get one of these which prevents invisible radiation being recorded by the sensor. HTH.

Thanks Alacant, posted as I was typing!

[alacant]

Ah, I should add this filter (I think) is only true for dslrs, especially modified ones where the uv and ir record as blue and grey on the sensor. I believe ccd cameas work in a different way. I'm sure someone more techie could do an explanation... 

[Nigel G]

48 minutes ago, parallaxerr said:

I've had a look back through the thread for posts about filters and came across two posts of interest.

@SteveNickolls, you mention using the semi-apo, have you tried it yet? I rate the 1.25" one I have highly for visual and am considereing the 2" for AP.

@Nigel G, you've had some success with an LP filter, can I ask which one you are using?

Thanks both.

I have the Astronomik CLS CCD clip in filter for the canon EOS cameras, so far very happy with its performance, light frames are dark blue instead of the orange brown colour, they look like they have less detail in but the couple of images I have tested on have been far easier to process and NO loss of detail, if anything more detail, Its primarily designed for Modded cameras but works well on unmodded cameras.

I took a 60s test shot at ISO 6400 to see how it looked , the resulting image was mid blue tone all stars visible with both flame and H/H nebula visible , not like a 60s at 6400 without the filter which is a total whiteout.

Around £ 110 but worth it.

Cheers

Nige.

 

[parallaxerr]

7 minutes ago, Nigel G said:

light frames are dark blue instead of the orange brown colour

Thanks Nige, this is my goal. The orange/brown makes processing so much harder! I'm really tempted by the 2" Baader Semi-Apo now, the Neodymium on which it's based gets good reviews for LP reduction and the fringe killer should help with CA, as I've observed with my 1.25" version.

[parallaxerr]

Oh well, impatience strikes again and I've ordered the 2" semi-apo. Below is an image showing the performance of the Baader neodymium on which the semi-apo is based, plus, based on my own experience with the 1.25" version, I should see less CA through the ST.