Which cameras should I get, given the gear I currently have

[oni]

Hello there. I'm trying to figure out what cameras I should get hold of for an upcoming astrophotography trip.

Im fortunate enough to be heading for Morocco. The hotel where I'm staying has several telescopes, star guiders and mounts - the only thing I really need to bring are the cameras (and laptop and the post processing stuff I guess)

Because I live in London, I normally travel to dark skies locations If I can, and that means portable gear. At the moment I'm working with:

Nikon D90

1.4f 50mm manual

11-16 Tokina 2.8f

Vixen Polarie mount with Velbon head and  Polar scope

T-Tube mount for mounting on telescopes

Sigma 500mm with a T Mount 

There are two things I want to attempt; nice landscape shots with the milkyway and deep sky objects. I realise they are both very different things to attempt. 

Reading around I've noticed people are fans of webcams, or even better, proper CCDs with Peltier cooling and the like. For deep sky images, I suspect this is the best option; riding on the eyepiece of a guided scope. This is my first question - can I start with a modded, reasonable webcam? I've seen a few cameras around £100 or thereabouts being used. Are there any recommendations or should I spend a little more for something a bit neater? I've read up on the debates of monochrome and filters vs colour and I think, to begin with, colour would be best.

The second question relates to my D90. I've been told Canon tend to be better for astro (most likely due to the ease of hacking the firmware). My D90 is lovely but it is quite noisy I've found, which isn't great. In addition, while the Polarie is also a lovely bit of kit, it is hard to align with a lot of accuracy unless you have a really, REALLY good tripod head which I don't. My tripod is one of the best portable ones but it isn't heavy or designed for astro.

I've seen some people talk about some of the newer Nikons - The D7000 was touted by some on this forum and I may end up going with that option. However, there are some impressive digital 4/3rds cameras out there (what some call 'compacts') - the Fujifilm Finepix x100s is one my friend has that has really low noise for such a high ISO, and I think it also has a bigger sensor than my D90. Im wondering if its worth making the jump to a newer format as I suspect the SLR will be on its way out in not so long (well, sort of).  Full-frame is pretty expensive and none of my lenses would fit so thats probably not the right move.

In short, which camera and webcam/ccd combo would be good to 'level-up' to?

Cheers

Ben

PS to keep this post a little more interesting, here is what I've managed with stacking, the D90 and the 1.4f 50mm 

[Knight of Clear Skies]

Webcams are great for lunar and planetary imaging but aren't typically suitable for imaging DSOs. It depends what your budget is and how invested you are in your current Nikon lenses. The D90 is a little long in the tooth so a newer model is certainly an option. For DSLRs and other consumer cameras an important point to consider is how easy they are to mod - the IR filter also blocks much of the Hydrogen Alpha signal from nebulae. Removing or replacing this filter gives much better results on emission nebulae.

Hope you enjoy your trip.

[oni]

Thanks for your reply!

Interesting... I'll keep on the SLR side of things. The modding you mention definitely adds another layer to this. I hadn't really considered it. I'm not particularly tied to my Nikon lenses and camera - I'd be happy to make a switch if its worth it. That said, I'm tending towards the 4/3rds solution as they seem to be generally more upto date and more portable, rather than a switch to Canon.

I'll have to update the D90 regardless then. Poor thing... it was an upgrade from a D100!

[oni]

Actually, reading up a little more, it seems that even my venerable D90 has a larger sensor than a 4/3rds and such cameras tend to have issues with amplification and therefore some noise even though they are more modern. Tricky indeed! I shall think on. Cheers

[miafey]

Keep the D90, get a cheap second hand Canon camera body and then have it astro modified. 

This is what I did - I have a D90 as well and got a modded Canon D350. 

[oni]

That is quite a tempting option actually. I'm not too familiar with Canons but I'll read up here on which might be best. Fairly happy doing some modifications. Should be fun! Cheers!

[Knight of Clear Skies]

One word of warning about self modding, the sensor position may need to be adjusted if you want to reach infinity focus with camera lenses. (I've used a couple of cameras modded by Cheap Astrophotography and they were fine, but a home modded one I tried could only be used with a telescope.)

[oni]

Funny you should mention that. Too many of my moon shots with the 500mm are too blurry, largely because I think it fails to focus properly at infinity with the T mount adaptor :S

[Charic]

I have the D5000 which has the same sensor as the D90,  and although I have not fully expanded into astrophotography just yet ( a few snaps ) as I don't have the means to track anything yet. I will probably use the method  used here before I go any deeper? 

The more I read, the more I see folk recommend Cannon for astrophotography. I'm sure the D90 will give satisfying results, although you will need to fully understand the basic and manual modes to get the best out of the camera.

Nikon now do the 810A (dedicated) which might be a perfect camera system ( not sure if you could retain any of your existing Nikkor lenses) but at just short of £3k, your holiday will cost less?

As long as the scopes you have access too on holiday are fully tracking, maybe just use what you have or even a mobile phone (cough!) and see what others are using whilst there. You may buy something in advance, that just might not suit or meet your demands?

[oni]

Top tips there - thanks! Im tending towards a second hand, newer Canon body and seeing how well it works with a telescope, and potentially moving towards that for astro work more generally. I suspect I won't see the benefit of a specialised camera just yet.

[cjdawson]

For the landscape shots, I think your D90 will most likely be ok.  The trick is capturing the images in the first place.  Use a wide lens to frame your shot.  Then you have two options.

1. Piggy back the camera on a telescope.

This will allow you to take the wide field photo with the telescope tracking a star. Before taking multiple exposures, take take several frames of different length to find the exposure time for the brightness that you want to achieved.  Once you find a good brightness for your exposure (maximum exposure time before star trailing happens) then it's time to take multiple exposures - the more you can take the better.   Then when you stack the images together, use an "average" or "mean" stacking technique to combine the images.  The idea isn't to make the image brighter, but to reduce the noise between the different sub frames.

(The full set of images needed to properly stack is image subs, dark frames, flat frames, dark bias and flat bias, but that's a whole other topic)

2. Non piggy backed.

For this, take long exposures, and keep the ISO down, the idea of this is to take a very long exposure - say 10, 15, 30, 60 min or more.   Keep the camera perfectly still in the exposure, and you'll get star trails.  This is really effective when you point the camera towards polaris.

For the DSO images, you'll need to attach your camera to the back of the telescope, ideally there would be a guidescope with a camera available, but if not, you'll need to improvise - The oldskool method is to use a reticule eyepiece to train the guide scope on a convenient guide star, then as you take the sub frames, keep the camera on target by eye - using the scopes controls to correct the tracking.  For this keep your exposures short (3 mins or so) longer if you can keep your concentration up.  Of course you can relax and stretch between frames.  As for the way to take the photos, again, this is the same set of photos for image stacking.

The Nikon V Canon thing is all about how the firmware in the camera handles astro photos.  Canon has produced specific cameras for astrophotography (20Da, 40Da, 60Da) they are very similar to their normal cameras, in fact some of the features were first tried on the Da version before being added to their normal line up (Live View as an example), that said, the canon firmware is more sympathetic to Astrophotography as the noise reduction techniques used in the camera tend to leave stars - Nikon's has been known to think that a star is hotpixels and remove them from the image, just what you don't want ;-)

I've seen some great photos with both cameras, so frankly, I'd not recommend switching from one to the other unless you really want to do it and realise that any lenses etc that you already have won't fit the other brand camera.

That said, I have a 30D and a 70D and have taken some fantastic shots on both cameras.

[GeoffB]

Thank you all for such a informative discussion as a Nikon nut I wondered why so many astrographers were tempted by Canon. I might decide to try a canon for primary focus shooting and compare it with my Nikon my oldest Daughter has strayed of thepath of enlightenment and got a Canon D1000 but I dont think she will allow me to butcher it in the name of science.

Has anybody come across a modified Nikon D50 as I have a few of those veterans which could be candidates for playing with as my nikon arsenal goes back to the Ark I could even try 35mm film plates on an ancient FG with a really long cable release setting. There after all is no chip to burn out just a piece e of kodachrome.

I might even have a old 1600Asa film up for the job as I sill take night shots of rock bands in both formats.

[oni]

Again, thanks for the tips!

Im thinking that a cheaper, second-hand, recent vintage canon might be worth a punt as I can use that with a telescope, potentially attached to the scope itself. I need to look into that a little more. I can use my Nikon at the same time, on the Polarie to take wider shots I think. I suspect that might be the most optimal solution.

I think trying a few things out is no bad thing - I'll have a few days to try most of these techniques and hopefully find one that works for me. I think I need to take a look at heads for easier polar alignment and more on CCDs.

[ollypenrice]

I'm an astronomy provider and would just sound a note of caution based on experience. It is far harder than you might think for a provider to be able to offer part of an imaging package so that the guest can provide the rest. It is not difficult to do so for webcam imaging. You just need a tracking mount and some long focal length optics ending in something to hold the nosepiece on the webcam. This is usually just a 1.25 nosepiece going into a 1.25 visual back without diagonal.

But, boy oh boy, it stars to get difficult for long exposure DS imaging. Here is a short list of offenders bent on sabotage!

1) Chip distance. Most flatteners require a specfic distance to be respected between flattener and chip and there is no industry standard for cameras, though DSLRs tend to be similar to each other. Most flatteners are optimized for DSLR chip distances by default but this needs checking.  CCDs often need custom parts and extension rings before they are right.

2) These extension rings love to get stuck either in the camera, the filterwheel or the telescope. Unsticking them can take hours and may involve the destruction of the offending part in extreme cases. This problem does not apply to Petzval refractors like the Tak FSQ and WO Star71 which have no chip distance, just a focal distance.

3) T thread is no longer universal. There are two other popular alternatives (if you call Takahashi popular.  )

4) The rig will need to be rebalanced and this may involve careful recalibrating of the autoguide system.

5) The cabling will need to be prepared and possibly altered if the rebalance radically changes the position of the scope.

6) If the autoguider has not been tested and tuned on the particular mount it may just work or, trust me, it may just not!

7) The entire operation violates a well established astrophotographic principle which states, Get it working and then never change anything at all.

For this reason I run two in-house rigs which never change and offer just a mount for visiting DS kit. While I do try to offer stuff to go on the mount I am careful to run through the points above. You wouldn't believe the hours we've spent in the workshop making brackets, drilling holes and removing spacers. It usually takes a few nights to make a new rig do just as it should. Sure, you can be lucky, but don't bank on it, especially if you are not very familiar indeed with your own side of the kit.

Olly

[Waldemar]

For what it's worth, I totally agree with Olly. A lot of pitfalls on your way to astro photography... and than,  when everything finally works together the next challenge: processing your subs...

A little hint to prevent bonding of spacers and such: use a very tiny bit of ptfe grease, just a tiny bit and before assembling leave it separated for at least an hour to give any solvents that maybe present the chance to evaporate, so they won't leave a haze on precious surfaces. It is not just the camera that is critical...EVERYTHING is critical with AP.

Waldemar