My first "proper" image with new setup, another Horse & Flame in Ha

[parallaxerr]

Despite the forecast, the cloud stayed away on Saturday night and I managed to capture my first decent image since moving to an EQ mount. The last few weeks have involved getting my new imaging rig up and running - learning how to operate the guider, getting the right settings in the DSLR and (reasonably) accurately drift aligning.

My setup now consists of a modded NIKON D3200, 7nm Baader Ha filter, Sky-Watcher ST120 Achro w/moonlite focuser, Baader MPCC as flattener and Nexguide with Starguider 60mm guidescope all on a belt-modded HEQ5 on 2" CG5 tripod with 18" pillar extension.

I have no view of Polaris so setting up consists of pointing the tripod North, eyed up with a compass and leveling the mount with a spirit level. I then go straight into drift aligning and so far I have not had to adjust the Alt bolts due to levelling the mount precisely each time I set up and I have only had to tweak the Az a degree or two.

I'm thoroughly impressed with the V2 Nexguide, very simple to operate and has guided 10 minute subs with ease, even when the wind picked up and got quite gusty. The 60mm guidescope is more than sufficient to pick up faint stars for guiding.

Here's the result - 2hrs 20mins on the Horsehead and Flame in Ha. 14x600s subs ISO1600, 10x600 darks, 12x flats and 12x dark flats, stacked in DSS, processed in StarTools. I hope to keep adding data to this over the next few weeks and the pick up an OIII filter to try some bi-colour.

My processing is not the best and I see very different results when I look at the image on different screens/devices, but I'm really chuffed with the result coming from a cheap Achro with a Newtonian coma corrector! Star shapes out towards the edges aren't perfect but I can live with it, not a problem on smaller targets of course.

Any tips/guidance gladly received, thanks for looking

 

[tooth_dr]

Looks great, so much detail in the Ha curtain behind the HH. And for what appears to be a quite an unlevel footing!

[parallaxerr]

1 minute ago, tooth_dr said:

Looks great, so much detail in the Ha curtain behind the HH. And for what appears to be a quite an unlevel footing!

Thanks! Yes my garden is all about slopes and steps, this is the best position I've found for maximum sky view

[steppenwolf]

A nice full view with plenty of detail. Achromatics are at their best in narrowband work where chromatic aberration id removed form the equation. Keep going with the data to get a smoother final result and be amazed at the beauty you will achieve when you add the OIII to form a bi-colour image.

[xtreemchaos]

great image and lovely setup Jon, I love mono shots I find colour distracting. well done.  charl.

[michael.h.f.wilkinson]

Great result!!

[Filroden]

Great first "proper" image. I'm currently debating with myself whether to reduce my exposure times so that I can gather more subs and get more out of linear fit clipping during integration. I know the CCD imagers achieve amazing results with small numbers of subs but CMOS chips do seem to like more subs (not least to restore bit depth if they are not 16 bit).

[MarsG76]

Looks Great!!!! nice one

 

[parallaxerr]

21 minutes ago, Filroden said:

Great first "proper" image. I'm currently debating with myself whether to reduce my exposure times so that I can gather more subs and get more out of linear fit clipping during integration. I know the CCD imagers achieve amazing results with small numbers of subs but CMOS chips do seem to like more subs (not least to restore bit depth if they are not 16 bit).

All a bit above my head but what sub length are you using at the mo Ken? I was considering trying 15mins next time out.

[Filroden]

4 minutes ago, parallaxerr said:

All a bit above my head but what sub length are you using at the mo Ken? I was considering trying 15mins next time out.

I'm using 4 mins for Ha but my camera has lower read noise than yours and much lower well depth, so I can't go as long without white clipping. I was actually thinking of dropping down to 2 min subs (and 1 min for RGB) and increasing the camera gain (ISO). I don't think this translates across to a DSLR though.

[The Admiral]

On 11/27/2017 at 10:08, parallaxerr said:

I have no view of Polaris so setting up consists of pointing the tripod North, eyed up with a compass and leveling the mount with a spirit level. I then go straight into drift aligning and so far I have not had to adjust the Alt bolts due to levelling the mount precisely each time I set up and I have only had to tweak the Az a degree or two.

Congratulations Jon on the first milestone of your new adventure!

Having to assemble all my kit each time I want to image, and what with the uncertainty over the weather, I've been loathe to move from my Alt-Az mount to an EQ one, because like you, I have no sight of Polaris. I'd like to progress though. There are very expensive options available, but it just is not sensible to shell out a lot of money on what is a very sporadic activity. So perhaps I should  just go for an EQ mount and face up to the alignment issues. You make it sound as though it is no big deal! How long does all your alignment take, and how difficult was it to do the initial set-up? It seems to be successful, if you're getting 10m subs.

Cheers, Ian

[parallaxerr]

Hi Ian & thanks, good to hear from you.

You ask a very pertinent question as I'm sat here trying to figure out a way to further reduce setup time! I too setup for each session, whilst trying to second guess the weather! I've managed to get quicker each session though, whilst learning new tricks...

The first time I drift aligned I decided that it was my only goal for the evening, so I took about two hours doing it. Having said that, there were complications due to the fact the mount was applying cone error corrections which I subsequently learned how to clear. With the HEQ5, cone error correction is automatically applied when you do a 3 star alignment and stays in the memory after powering down, so I was getting some wildly innaccurate gotos. There's an option to clear it in the handset but it's not overly obvious, once cleared though, it can be avoided by only doing a 1 or 2 star alignment.

Anyway, I digress. The good news is that having taken my time to level the mount before my first drift align, I have subsequently not had to make any Alt adjustments, provided I level to the same accuracy using a spirit level.

I use a compass to align the mount roughly North and using the DARV drift align method I align in Az (method here...https://www.cloudynights.com/articles/cat/articles/darv-drift-alignment-by-robert-vice-r2760). Once you realise how much Az adjustment is required to correct the deviation angle in the drift align subs, you should be able to align "close enough" in two or three iterations. Last time out I made just one correction and the mount reported just over 1° of alignment error, but the guiding easily dealt with that (some say a slight misalignment is a good thing as it keeps the guiding corrections going in one direction) and I didn't see any field rotation, just a very small stacking artefact in StarTools. Drift align subs can be as long as you want, longer is better but 2mins 5secs works for me.

@ollypenrice suggested I only need carry out a 1 star alignment after drift aligning, in the region of the target and he was dead right. This combined with PAE (positional accuracy enhancement - a bit like Celestrons extra alignment star option) on a nearby star is perfectly sufficient to put the target on the chip. I use the same star to focus in Ha with the Bahtinov mask using maximum zoom on the camera screen, then one or two high ISO 5s subs to confirm.

On to the target, a few short, high ISO subs to frame it and lock the focuser down.

Then it's on to the Nexguide. Again, having previously spent an evening on this alone, it now requires very little effort to get going. Focus is fixed (and doesn't need to be perfect) and all that is required is to adjust the exposure time to pick up a suitable star, auto-lock it and hit auto-cal under the guide menu and away it goes, starts guiding after about two minutes.

Then I go indoors and set the remote intervalometer whilst the mount settles into it's guiding. Hit the release button and away it all goes. Retire to the sofa

 

A bit of a ramble sorry, but to summarise...

1. Setup mount level and facing North.

2. Drift align in Az. Target going forwards is <1° error.

3. Reboot mount, 1 star align near target, fine focus and apply PAE.

4. Frame target.

5. Start guiding.

6. Start imaging.

 

And finally, to answer your question - that lot took about 40mins last time out with a few hiccups along the way. I aim to get down to about 20-25mins, which I think is realistic. I was hesitant to take it all on at first but I must say it all makes sense once you do it a few times and it definitely gets easier. I did try unguided to start with but that wasn't really successful, even after 5-10 drift aligns on each axis. Guiding really does do the magic.

I really do question how I got into this sometimes, I'm sure someone on here encouraged me to start imaging. Oh yes....it was you

 

[Filroden]

49 minutes ago, The Admiral said:

Having to assemble all my kit each time I want to image, and what with the uncertainty over the weather, I've been loathe to move from my Alt-Az mount to an EQ one, because like you, I have no sight of Polaris. I'd like to progress though. There are very expensive options available, but it just is not sensible to shell out a lot of money on what is a very sporadic activity. So perhaps I should  just go for an EQ mount and face up to the alignment issues. You make it sound as though it is no big deal! How long does all your alignment take, and how difficult was it to do the initial set-up? It seems to be successful, if you're getting 10m subs.

It's a shame you don't have a view of Polaris as SharpCap has me polar aligned within 5 minutes time and under 10" in distance. I literally plonk down the mount roughly pointing to magnetic north, put on the scope, do a rough focus (i.e. find the point I was in focus on the previous session) and run the process. 5 mins later and a quick star align to get the goto working, and I can start my imaging.

Without a view of Polaris you have two options: drift align, which I got working once but found it quite slow (and you should have a view to south and at least one of east or west)., and, for Celestron mounts, their ASPA routine which works similar to SharpCap but for any part of the sky (though I found ASPA to be nowhere near as accurate as SharpCap or drift aligning).

I'd recommend bulldozing the offending tree/house!

[parallaxerr]

12 minutes ago, Filroden said:

I'd recommend bulldozing the offending tree/house!

Had that thought Ken, unfortunately the offending trees give the garden some privacy.

Another factor for me is that I wanted to be PC free, so no software alignment options are avaialble.

Does sharpcap require a view of Polaris?

[Filroden]

18 minutes ago, parallaxerr said:

Does sharpcap require a view of Polaris?

It does, and so does the similar tool being developed for inclusion in PHD2. It uses plate solving, and you just rotate the RA by about 90 degrees for it to know where you have to adjust the axis.

[The Admiral]

2 hours ago, parallaxerr said:

I really do question how I got into this sometimes, I'm sure someone on here encouraged me to start imaging. Oh yes....it was you

[The Admiral]

2 hours ago, Filroden said:

I'd recommend bulldozing the offending tree/house!

But where would I keep my 'scope?

Ian

[Astroblagger]

Great start! Nice horsehead. 

[parallaxerr]

Well that went well. Talk about reducing setup time....

I had a 2" filter wheel arrive today so I popped in my Ha and 495nm longpass filters and obviously have 3 spare empty slots to be populated by SII, OIII & a clear in the future. You can just make it out here...

 

Went outside to setup, did my first align using a clear slot in the filter wheel and the handset reported <1° Az error. Went straight into drift align using the 495 longpass to get tighter stars and got this...

Az&Alt

A final focus in Ha and all set to go in less than 15 mins

Only curveball was a really bad glare/flare with the filter wheel fitted when I briefly pointed at the moon. Will have to keep an eye on that, hopefully not an issue on DSO.

 

 

[The Admiral]

Excellent progress Jon. I shall need to keep an eye open for your threads!

Ian

[parallaxerr]

Well I took a gamble and left the scope out all night as the weather forecast showed clear and the weather radar didn't show any incoming rain.

I struggled to frame the target the same as my previous attempt so started afresh and captured 6hrs of subs and 2.5hrs of darks.

Here's a quick blip through StarTools - there's a bit more cloud detail and less noise, really want to add OIII to this now

 

[The Admiral]

Coming along nicely, but that's some exposure! Did you sleep soundly?  . Did you need a meridian flip? I guess a dedicated mono astro camera wouldn't need such an exposure to get the same result.

Even if the framing isn't exactly as before, couldn't you still stack the subs from both exposures together?

Ian

[parallaxerr]

7 minutes ago, The Admiral said:

Coming along nicely, but that's some exposure! Did you sleep soundly?  . Did you need a meridian flip? I guess a dedicated mono astro camera wouldn't need such an exposure to get the same result.

Even if the framing isn't exactly as before, couldn't you still stack the subs from both exposures together?

Ian

Well Ian I've got a stinking cold so I'm not sleeping at all well anyway! I went in the back bedroom where there's a velux overlooking the garden so I could cast an eye on the scope every now and then and I did pop out twice to change the camera battery. It was my home made power tank that ended the run of light frames, the alarm went off at about 3am, it was all very crunchy and icy but the dew heaters performed fine at 50%. I then parked the scope and set the darks going.

No meridian flip was necessary, I've got it turned off at the moment as there's loads of clearance around the pier extension.

In the process of stacking the two lots of data together right now (remotely from work!) so It'll be interesting to see how much fov is left after cropping out the artefacts. Watch this sapce...

[parallaxerr]

Frames were about 30° mis-aligned but still got a decent crop out of the stack. Not sure there's much more detail there though?

 

[The Admiral]

Hmm, not sure I'd agree with that. Seems to me that the 'cloud formation' to the right of the head is a bit better defined, though it may just be the larger scale of course. Into the realms of diminishing returns I guess.

I like that. Be interesting if you do manage to get some OIII too.

Ian