Getting a better pic of Orion etc.

[SilverAstro]

12 minutes ago, JOC said:

19 frames in both RAW and JPEG formats that look a bit like this one.

10 Second exposures. 

will 19 frames like this do?  How have I done with the learning?

Yea! Brill !! Well on your way now, that is good news indeed Yes 19 will do very nice, almost as nice as 10 x 20secs

The learning, ummm what yo rekon h-k, about as good as the teaching ??

apart from our many earlier heavy hints to go for a longer exp. at 18 I think done very well as a pupil chuckle

Very nice, good colours, good view and doesnt the moon always try to get in on the act ! Love it. Like the 'in context' second one also.

 

[SilverAstro]

which you have reminded me to look outside and surprise, we have a clear sky also

19 is good to go to the next stage, so if you still have clear sky, nip out and take some singles at for example 15, 20, 25 or whatever takes your fancy, just to get a feel for how the star trailing if any progresses and what your limit may be.

In fact take some longer ones (moonlight limiting?) to do a star trail composition ?

 

[happy-kat]

Rain here!!!

[SilverAstro]

If you find that at say20sec the stars are still tight, then do a load more at 20 and you can add them to your 10s

you will also then have the back cat. to be able to compare a stack of 10sec  alone with a stack of 20sec alone and thus get a feel for how the noise gets suppressed.

 

[JOC]

OK, I had dashed back outside after H-K's first response and missed all the next things to try!

However, you know you've been a bit smug when the after the next two frames the entire top of the tripod inc. the camera topples off the rest it and heads towards the ground, to be recovered by lightening reflexes just before it gets there!  Phew.  Took coming back inside to fix.

Outside again - Orion has gone up - can no longer fit into landscape view and get some foreground.  Have turned camera on side and attempted portrait view.  Haven't checked how many or how good yet - a good few at TWENTY seconds.  It's a Thursday again like last week I now have to dash out, will catch up tomorrow and see what else I got.  NB.  Clouds are coming over now :-(

EXCELLENT TEACHING CERTAINLY :-D

[SilverAstro]

Phew!

[JOC]

I'm back and just before bed couldn't resist a quick peek.  I've got 14 of these all at 20 seconds all in RAW format.  I really must see if there is some way of cleaning up the camera system!  There seems way more stars up there than I can see with my naked eye!

[knobby]

Looking good, slight trailing still but ok.

When using the 400 or 500 rule I think you need to multiply the lens length by the crop factor of your camera (1.5 Nikon 1.6 Canon) so maybe try 15 seconds .

[SilverAstro]

Interesting

Yes trailing,  now we can see why I (gently ) suggested a sequence of 10, 15, 20 sec whatever , should have been a starting calibration ?

So now we can begin to set the parameters of what is reasonable for JOC without believing all one reads on t'internet we,  I mean JOC,  can now set the Konstant in the equation (as a personal constant in semi-scientific circles) without ref to some 'website' iyswim ???

Because the trailing is only, now,  there if pixel peeking -  for other viewing options it may not be important ( it's significance when stacking is a whole other topic )

but at least we, JOC, can now decide if 500 is a good number +/-  ?!

 

[happy-kat]

That's why Knobby I go on the 400/focal length of lens as allows for the smaller sensor in my 1100d.

That's great you got more photos. Does look you have a whopping dust bunny either on lens or sensor, I find those rubber rocket blowers great for removing dust lumps.

[JOC]

So we have @SilverAstro's equation 

T=K/fl

where K is a Konstant  , fl is the variable and T is the dependent variable = allowable exposure Time.

K is 500 or 400 or whatever your personal tolerance is upon pixel peeking your test exposure.  ( <edit :  of Orion in this case to take account of h-k's good point about the celestial sphere !)

@Knobby suggests we mulitply focal length by 1.6 to cope with 'the crop factor' of my camera, some mystical, but it seems important property of cameras ;-)

So if we assume that I am at 18mm then with the crop factor we are up at 29mm. 

500/29 = Somewhere around the 17 second mark.  We know from the 'Now redundant' 20 second ones (which I will ditch) that the star trailing has started so that would appear to be in alignment with that calculation.

400/29 = exposure of 14 seconds - around 15 seconds is sounding good isn't it?  You guys know your gear don't you?   ;-)  :-D

I wish I hadn't been so enthusiastic last night and had read the instructions about trying exposures at different times first, but I am always tight for time on a Thursday and I had been so pleased with the trial landscape shot that I thought I'd try a few more at the higher exposures as had been suggested and just rushed straight back out before the postings were there, I guess I should have reined in my expectations and not made such a big jump.  Just need another one of those rare clear nights.  I'm liking this photography lark though - I can do it quickly without planning or dumping the kit outside and my lounge stays tidier because I don't have to get all the telescope stuff out.

Maybe there is something that I could try with the 19x10 second pics. ?

[SilverAstro]

15 minutes ago, JOC said:

We know from the 'Now redundant' 20 second ones (which I will ditch)

No dont do that, well not yet anyway , use them stack them, see the difference longer exp makes to nebula and background.

 

[JOC]

2 minutes ago, SilverAstro said:

No dont do that, well not yet anyway , use them stack them, see the difference longer exp makes to nebula and background.

OK, I'll have a fiddle with some the free bits of stacking software I've downloaded and see if I can make them work.

[SilverAstro]

The trailing is tiny and stars are not always everything, there are loadsa nebula in that region and they are less sensitive to trailing but do need lots of exposure.

Use them (and the 10secs) to delve into the mysteries of DSS ( that should keep you busy for the next few weeks muwahhahhh )

Then later still you can get up to tricks of extracting the nebula from the 20s and paste into the stars from the 10s  !

ah we are typing at the same time !

 

[happy-kat]

Full size sensor cameras use the 600 rule, as they have a full size sensor.

'Crop' sensor dsls are where the 1.6 comes in.

However I find it easier to just start with 400 and forget the 1.6 as some camera makes use 1.5 for example.

400/18 = 22 seconds. If you are pointing high t the South you may find that 22 seconds is too long, if you are pointing West and fairly low then 25 seconds would probably be fine.

[happy-kat]

If your images have foreground in the view then go straight to sequator. It is very similar to dss but will handle and keep your foreground.

[JOC]

I've just read about that Supernova near to Sirius (which I think I've got in shot?) I wonder if the stacking will reveal anything?  I'm quite excited just to see what the stacking might reveal - I've often read about the process and see some of truly magnificent ultra definition shots that result both of the sky and on earth, but I've never had the shots to experiment myself. 

[JOC]

Just now, happy-kat said:

straight to sequator

I don't think I've downloaded that one - I'll pop off and find it!

[SilverAstro]

1 minute ago, JOC said:

I've just read about that Supernova near to Sirius (which I think I've got in shot?) I wonder if the stacking will reveal anything?

You are a mind reader ! I was composing a reply (now redundant! thank you ) on that very thing  !

[happy-kat]

DSS will do a super job of your stars but your foreground will get smeary. Sequator will stack the stars and keep the foreground static.

[SilverAstro]

Wont you be really excited if you have got it in the stack of 20s ! You wont be the least bit bothered if it has a tiny trail then 

First rule of astrophotography - never throw anything away,  they are still using the Palomar survey and others from yonks ago

 

[happy-kat]

^ ditto, star shapes can be improved in software, I'm liking StarTools some clever stuff in there, but that's for future if the bug bites.

[JOC]

Sequator seems to be dead easy to use - this is a good plus point.  Basically keep clicking the options and reanalysing until the picture resolves into what looks acceptable (this is NOT the default setting on my faltering starting shots LOL) 

So I've got a starry shot ( no evidence of the nebula - perhaps it was that filter - see below) - rather marred by an airplane trail that must have gone across and a rather pretty picture (if you ignore the dust bunny).  The 20 second one had lots of trails as you all suspected it might.  I may have tracked down the dust bunny - I've spotted that the lens had a UV filter installed - in my excitement last night I had overlooked that and should have removed it.  When I looked through it I'm pretty sure the filter was responsible for the dust bunny.

 

[happy-kat]

Yey glad that worked for you.

If you resize and saveas png or jpeg you can add to your post?

Sorry but I wont/very reluctant download images to my pc in order to see them.

[JOC]

6 minutes ago, happy-kat said:

Sorry but I wont/very reluctant download images to my pc in order to see them.

As you wrote I was the cursing the .TIFF format and doing just that!  See above

I like software, but sometimes it does stuff you don't expect - I was running the natural progression that because a JPEG displayed in the thread a TIFF would and it didn't!  In actual fact playing with software generally ticks my boxes - I like making it do what it was intended.