Meanwhile Back in Nikonia

I was out one night earlier in the month trying to image M31 with the Nikon P900.  The results were pretty dismal.  Below are my three best tries.  The first one is from a starscape video so 25 sec ISO 100 and the others are ISO 6400 1/2 sec.  In each case you can see the Andromeda Nebula as a smudge.  The smudge is pretty blocky in the video frame.   I looked at a number of the frames and they were similarly blocky so i doubt that stacking would make a difference.  So the Nikon makes night sky photography easy and fun but not that rewarding – the sensor is just too small.

DSCN2006_Moment (3)DSCN2035 (2)DSCN2034 (2)


HaHa – Had It All Along (Sort Of)

The plate solver web site gives you a bunch of information about your image like field of view. I wanted to get the info for the Nikon so I went back and picked an image that was done at wide angle and fed it in. Lo and behold, there was Hercules front and center. This is exactly the starting point I was looking for to trail my way up to it. The image is not much good because it was done at reduced resolution and i had to boost brightness and contrast all to heck to get it recognized. Still, it’s an excellent start.
At the left bottom is the handle of the dipper and top middle is Hercules.

This was shot with the Nikon at its widest setting-24mm equivalent, ISO 6400, f/2.8, 1/2 sec. The resolution is one quarter of maximum at 2272X1704. I boosted it to +35 brightness, +100 contrast with Paint Shop Pro.

The plate solver output is shown below:

19-07-20 plate solver


Mooning Saturn Again

19-07-16 Titan 1799
Hey Bingo. To nights later and the “Titan” pinprick is in a different spot. Saturn itself has moved against the fixed stars as well but that’s fine. As usual the only thing that’s moved between the pictures is me! The earth has moved two degrees around it’s orbit(almost 2 million miles by the way) and parallax shifts Saturn accordingly. I may need to do the math on that for fun.

The image was done at full zoom f/6.5 ISO 1600, 1/2 sec. It’s cropped and the adjusted in Paint shop pro: +35 brightness, plus 97 contrast.

Mooning Saturn

19-07-13 Titan 1765
The yellowish blob mid right side is the planet Saturn(overexposed). Just above and to the right is its largest moon Titan. Titan is 5,000 km across which is big but it’s 1.3 BILLION km away and the light I captured had to travel 1.5 billion km from the sun out to Titan to get reflected back. The other pinpricks are stars that are too faint to have proper names.
This was taken at 1800mm focal length, f/6.5, ISO 6400, 1/4 second. Titan and the stars above and below saturn are all magnitude 9ish. The brighter one over to the left is mag 7.5.
The real trick here is to get back out again tonight or tomorrow and make sure that one pinprick has moved and others haven’t!


19-07-09 saturn
These were done around 10 pm July 9,2017. Camera was set at ISO 100, 1/50 sec, f/6.5. Zoom was at max optical and 4 X digital(gives a “focal length” figure of 1428). The picture size was set at 2272X1704 to reduce the effect of digital zoom. The planet with rings occupies about 100X55 pixels. These were cropped and brightened with paint shop pro +21 brightness, +21 contrast. If I do it again I’ll go up to 200 ISO.
19-07-09 jupiter 1731
The Jupiters were done at full optical zoom. The three larger ones were 2X digital zoom with picture size at 4608X3456. The smaller were 3X digital but with the picture size cut to 2272X1704. The settings were ISO 100, f/6.5. The first four at 1/60 sec, the last three at 1/100. Jupiter is 100X100 in the larger ones, 60X60 in the smaller. The images haven’t been brightened.

I would say the digital zoom might be worthwhile but cutting down the picture size is no benefit. I’ve just discovered the camera had adjustments for sharpening etc. These would have more effect on star photos but i’ll try neutralizing them.

It occurs to me also that saturn has a ton of moons. They are dimmer than jupiter’s in the mag 8-9 range which might just be visible in a long exposure.

Perhaps I’d like a Cigar(Galaxy)

I’ll keep trying for the Pinwheel but, If I can find it, Bode’s Galaxy and the Cigar Galaxy, also near the big dipper may be better targets. They have higher surface brightness which is more important than pure magnitude for deep sky objects like galaxies. In stellarium I have no trouble finding Bode’s – it’s above and outboard of the bowl about the same as the diagonal distance across it.
19-07-06 bodes galaxy M81

There’s a sort of right angle construct half way to bodes that may help. Supposedly it’s visible in 50mm binoculars which may help. Also, at 35mm on the canon(56mm equivalent) with the whole bowl of the dipper in frame bottom left, Bode’s galaxy would be centered in the frame.

More Stars, No Smudge

I tried last night 4 second exposures at ISO 400, 300mm focal length and f/5. I took 10 shots tried a few ways of stacking them including deepskystacker, rotn’n’stack, layers in paint shop pro, and a home-brew python/opencv program that just added the pixel values. The best result I got was rot’n’stack. Four seconds is clearly pushing it, the stars show definite trailing but it’s not awful. I certainly see stars that didn’t show up in the ISO 6400 1/2 second images. The two below the red circle where the pinwheel should be are magnitude 8 and 9!
Unfortunately, the 4 seconds at ISO 400 is sort of a sweet-spot. The slowest speed at ISO 800 is 2 seconds which would be the same. I can try ISO 6400 1/2 second which is nominally better but that’s what i had tried the other night.

With the Canon the longest focal length is 85mm equivalent so I could go to say 15 seconds for equivalent trailing and i could use ISO 800 or more but at 80mm focal length equivalent the smudge would be pretty small and at f/5.6 the light gathering is lessened. I may try it on the next clear night along with 1/2 sec ISO 6400 on the nikon. Playing around with telescopius I think that, at 85mm on the canon, M101 would cover about 1% of the sensor which would translate to a bunch of pixels.

Also from telescopius I get the following charts for pinwheel which shows surface brightness as 23.8 mag/arcsecond. I think that’s very dim. Andromeda at 22.2 is just a bit better. Bode’s galaxy at 21.7 a bit better still.

Somebody on reddit just told me i’d need to stack hundreds of exposures to see it – that’s not going to happen!

But If I *Could* See That Smudge…

In this image Mizar/Alcor, the double star in the handle of the dipper is just barely visible in the bottom left.  Follow the four star trail up to the right in his picture(but left from Alcor) then go to the middle star in the group of three off to the right, twice that far again then down a bit and there you are!  This image was done at the usual ISO 6400 1/2 sec. it’s only at 105mm zoom so if i can do this effectively i can re-center and zoom further.  I think i can see the trail of four stars in the LCD although they’re magnitude 5-6.  the spray of three i have to take on faith.

19-06-20 where is pinwheel 1483

in the gallery below the left hand shot is from stellarium and the right hand one is the original of the image above.

The pinwheel Galaxy by the way is almost 1/2 degree across – 24 arcminutes by 23. That’s about 40-50 X the size of jupiter at opposition. I just measured jupiter at about 57 pixels zoomed to 2000 mm so if my half-baked math is right it would cover say (40*57)*(105/2000) or about 90 pixels. That’s 1/6 of the size of the green circle. Zooming is definitely going to be needed although I’d still cheer for an encouraging smudge.

Also, I note in passing that Bode’s Galaxy is magnitude 7 so may be easier to see if i can locate it.

UPDATE: Checking again, those images are at 300mm equivalent zoom so the pinwheel might cover (40*57)*(300/2000) or 340 pixels. My best hope for improving my resolution is longer exposures at lower ISO. At 300mm the rule of 500 says anything more than 1.6 sec will smear but i’m working relatively near the pole and maybe the size of the object will work in my favour. Again, I’d be glad of a smudge at this point!

Playing with the telescopius camera simulation it says the pinwheel measures about 17 pixels across in a 550 pixel image – call it 1/30th of the field of view so 150ish pixels – certainly sizeable but i must have botched the jupiter comparo.

Scorpio Rising (also Libra)

I quite like this image of Scorpio rising over a country road near me. Bright Jupiter is on the left, then Scorpio with Libra a bit above and to the right. I greened the stars in Libra because it’s faint but Scorpio seems very nice as is. The three stars arcing up into the spray of three stars somehow bring to mind some sort of creature – why not a scorpion!
19-06-15 Scorpio-Libra 1457
Taken 10:30 pm June 9 looking south using the P900’s starscape setting which takes a “movie” at ISO 100, 25 second exposures. I stacked a couple of frames using rot’n’nstack and brightened it just a smidge to bring up the landscape a tiny bit.