Astrophotography with the 400mm F2.8

[Big V]

I have been wanting to do this since I purchased this lens, well last night I finally got around to making up all of the adapters to fix the lens to the telescope mount and decided to give it a go. These images are not guided and have not been calibrated as it was a proof of concept night, so no darks, flats or bias frames taken. These were shot as JPG at 1600 ISO and are 12 x 1 min images stacked together. Hope you enjoy the wonders of the night sky!!

[fozzie]

Virgs - WOW factor comes to mind. Just love the colours and action displayed in #3 & 4

[wendellt]

the full res versions must be majestic
you must live in a pretty dark area to get shots this clear
great work

[aim54x]

amZing stuff...if this is what you can produce on a proof of concept, I am really waiting for the final results!!

[DanielA]

Awesome shots V.
The colours seem richer than than I remember your previous telescope shots.

Daniel

[PiroStitch]

That shot of Eta Carinae is fantastic! Didn't realise that you can see those colours as is.

[craig.rohse]

These are amazing hope to see more of them!!!

[sheepie]

Amazing detail! Am surprised at just how much you have been able to capture at only 400mm

Am I right in taking from your desription that you haven't tracked with these and the clarity is because you have used one minute exposures stacked?

Nicely done, and looking forward to seeing the results when you actually put some real effort into it!

[BBJ]

Geeze Virgs, better get that camera checked out , The dust bunnies are bad.LOL Nah great stuff mate have said many times glad you know what you are looking at.
Cheers
BBJ

[photomarcs]

These are really sweet looking images!
Love the second one =D

which adaptor did you end up using? I've been searching for an eos to telescope, yet didn't realise that it had to be attached to a lens.. or does it not?

anyways great images !

[bigsarg7]

i must ask, how have you taken these remarkable shots? they are awesome!! love it, the colours, clarity all of it, fantastic!! job very very very well done!! i'd pay to hang something like that on my wall!!

[Big V]

OK here is how I have done this. I have attached the camera and lens to a telescope mount which has motors in it. It was attached to the telescope mount by a custom bracket which I fabricated out of adapting a manfroto quick release plate to the base plate of a telescope ring set. Now as the camera and lens weighs 8kg combined, I had to add counter weights to the telescope mount. Once all of that was set up, the motors on the mount were turned on. These move the camera and lens to counter the rotation of the Earth, which is what gives the impression that the stars are moving across the sky.

Under normal conditions when I do this I have a second, smaller telescope attached with an autoguider camera attached - this locks onto a given star and sends pulses to the motors of the telescope mount and fine tunes the tracking so that you do not get bloated, elongated or wobbly stars on th elonger exposures that I normally do - think in terms of hours, will attach an example at the end. Due to the fact that I was using a brand new laptop with windows 7 I could not use my old autoguider on the night, so I had to make do with shorter exposures and then stack them, luckily a 400mm F2.8 gathers a lot of light at a cool resolution and the mount is accurate enough over this small time frame. Once the new autoguider arrives, I will be taking frames of between 10 and 30 minute duration and then stacking those - then we shall see some extreme detail in the images.

Now as an example of why stacking frames works, here is for example (this is not a very good result due to high temperature the other night) a single 10 minute image of 800 ISO versus 4 hours of 800 ISO. This area of the sky was taken through a large telescope and autoguided as mentioned above. It shows the region in the bottom left hand corner of image two above.
The single image - as you can see very nosiy and not much colour...

Now for the 4 hour exposure and as you can see it looks better (although I am not happy with this because there is still noise etc)

However you can see that there is much to be gained from going longer with the exposures and why I am so happy that the 400mm is going to work out so well for this purpose. The other advantage is that it is a portable setup so I can easily move it to dark sky locations when I travel around Australia.
Hope this helps in understanding of how I have made these images...

Forgot to add, the lens was atatched directly to the camera for the first 4 shots. For the second 2, I used an eos T - Adapter to attach the camera to a 2 inch diameter tube which then slides into where the telescope eye piece lens would normally go. These adapteres are about 30 dollars fromk most higher end camera stores or any telescope store.

[bigsarg7]

wow!!! now thats an explanation!! lol

Can't say i could do it, but flip what a difference between those 2 shots, incredible!! inspiring actually!! thanks for explaining it!!

[zafra52]

Great images and even greater patience to take them.

[dawesy]

Awesome work.

I have had a few tries at capturing star trails with limited success, but this has really got me wanting to give it another go!

Have you used long exposure noise reduction in the 4 hours image? it just seems to clean compared to the mess I get when I expose that long. My images are unusable after that length of time.

[surenj]

These are incredible BigV!

long exposure noise reduction in the 4 hours image

Without knowing too much detail, wouldn't this take an extra 4 hours to do? = You will have an extra 4 hours downtime while the camera does the noise reduction?

[dawesy]

Without knowing too much detail, wouldn't this take an extra 4 hours to do? = You will have an extra 4 hours downtime while the camera does the noise reduction?

Sure would. This is why I haven't used it for things that long, but I'd be willing to give it a go for shots like that. It literally means one shot a night though!

[Big V]

Good question about the noise. Here is how i do it. As each frame is 10 minutes long, I take a series of 10 minute dark frames - these are at the same ISO but there is a body cap on the camera. I take 16 of these and median combine them to make a Master Dark Framel. Now I can subtract the Master Dark Frame from each of the light frames. I also take 16 bias frames and median combine these as well. A bias frame is the fastest shutter your camera can take, so for my camera it is 1/8000th of a second. A bias frame is used to measure the electronic noise generated by just turning on you cameera and again by making a master of these I can subtract out that noise as well.

The last bit of calibration required for these extremely long exposure shots is flat frames. These are a picture taken through the telescope of a white surface which has been prepared in the dome. Flat fields are used to take out any vignetting or optical defects that may be in the image train. Again 16 of these are taken and a master is used. If the temperature is the same you can re-use the dark frames and the bias frames, if you left the camera attached to the telescope you could also re-use the flats but if you make any change including rotating the camera another set of flats is required. All of these are done as raw files as JPG would create random patterns.

Now one of the reasons I am not happy with the above horse head image is when I took all of the calibration frames it was much hotter than when I did the light frames, which is always a risk at this time of year - normally you would use the night of a full moon or rain to do all the calibration files so that you do not waste a good night. I am currently working my way through developing a library of darks at different temperatures and exposures so that they can be ready for future imaging runs but as you can see from above it takes time to do all of this but it is something I am looking forward to completing as the quality of the images will improve as a result.

When using the telescope I usually plan on one target for the night or in winter because we get more time maybe two and this is what is so exciting about using the 400mm F2.8 as an astrophotography device - it is just so quick and will allow me to image a number of targets in one night. The telescope is F9 and has a focal length of 2500mm which is great for resolution but it takes so much longer to gather those photons.

[dawesy]

Firstly - wow. That is a seriously detailed and well thought out work flow and I thank you for sharing it with us.

Secondly, thanks for the details, I though that images was one 4 hours shot, hence my amazement, but it makes a bit more sense now. The dark images to remove noise is an extra step I hadn't considered, and something to look into if I do find this becoming addictive. The bias and flat frames for correction is something I would have never even thought of!

Do you find that also helps with star trail photos? Not having any of the tracking gear, or even a telescope, that is where I'd be starting. I think I need to organise a trip to the country in the New Year and get away from all this light pollution for a play.

Thanks for sharing your spectacular images and so much detail about how you achieve them. I doubt I will ever produce anything that spectacular, but it will certainly assist the next time I go camping and point my camera at the night sky.

Cheers.

[radar]

Amazing photos Virg and thanks for the details on how you achieve this, you show some great dedication and you have the results to prove it.

The last one would be my favourite.

Cheers,

André

[adame]

Very cool mate, was wondering when you were going to get around to dooing this

[paulmac]

[cough] Stellar work, Big V.

[biggerry]

Top work Big V - thanks for the detailed posts, it was a great read!

[Big V]

Okay, Star Trails and how I do those..
here is an example of what I am talking about this is a total of 6 hours..from a previous post

Now with the star trails you do not need any equipment other than a tripod and a cable release as well as the ability to use bulb exposure. This image is 6 hours worth of 5 minute exposures at 800 ISO and F4 with a 17mm lens. A 5 minute exposure will produce a little bit of noise but because you are going to combine a total of 72 images, the noise will be beaten down by the signal and as such you will not need to do calibration frames. In fact for star trails I shoot JPG because of this fact.

When you combine the image you are going to use the blend option of lighten in photoshop and what this does is adds the signal to the previous image where a change has occured i.e. the new star position. As a result of this blend option you beat the noise down to almost nothing. Why do I use 5 minutes? I have found from experimentation that I get enough star movement and not much noise with this combination. Also if I used shorter exposures then I would have a lot more frames to deal with and this would take longer to process, so this is the best ratio for me anyway.
Hope that makes it easier to undrstand and now I look forward to seeing what the members can produce over the holidays.

[dawesy]

I remember this image from when you first posted it, I rather like it! I read through your descriptions at the time but with this extra info I think I have my head around it this time. Sadly, I won't be out of the city before the new year but with any luck I can try to put this into practice soon!

Again, thank you for sharing so much with us, it's what makes the forum such a brilliant resource.

Cheers,
Jon.

[Mj]

Now this is a timely thread as I've just been toying with thoughts of buying a telescope for astrophotography and general gazing... sounds like you know your astro stuff Big V.

I'm considering either a sct or mct tube with goto motorisation but not clear what size tube or eyepieces I should be getting... I'd love to get an understanding of what results you can achieve with an 'affordable' setup... but as with all things photag I've learnt that sometimes saving money at the beginning can lead to greater expense in the end.

Look forward to your words of wisdom...

Michael.

[Wink]

Awesome shots!
I can't wait to see the real thing if these are test shots!

[Big V]

Michael, as with everything in life there are advantages and dis-advantages to the different types of telescopes. A SCT gives you shorter tube length which is better in windy conditions as it does not act as a wind sock. They lose a little bit of contrast because of the secondary obstruction. As they are a closed system they take longer to cool down unless you do a peltier modification, which whilst not for the faint hearted can be done and the best example of this is Paul Haese's 14 inch celestron mod. The newtonian telescope is often much cheaper for the same aperture but being a longer tube they do act as a wind sock. The MCT gives great contrast but is often a higher f ratio so just that bit slower photographically. They have the same cooling problems as the SCT but are noticeably better on planets and moons. As for mounts, the EQ6 pro has proven to be a real winner and really can not be beaten for price. I have just prurchased one to try out and have been extremely happy with it. It supports ascom and when you combine this with the free eqmod software it is so versatile - indeed I can control the mount with a wireless logitech controller, pretty cool stuff.
3 grand will get you an EQ6 pro mount, 8 to 10 inch newt and a 10mm, 25mm eyepiece plus all of your little extras like battery cables etc. If you have 5 grand to spend then we are talking a whole new ball game!!!

[stubbsy]

Virgs

Like the others I'm impressed by your "not happy with" shots.

More importantly your fantastically detailed explanation of your workflow was a brilliant read. While I'm certain I'll never have the patience for this type of photography it reminds of one of the reasons why forums like this are so great - thanks to you I now know a little about the patience, planning and dedication involved in getting such marvelous images of our universe and my life is a little richer for that knowledge. I thank you immensely for taking the time to write up this detail and for sharing it with us. I also look forward to the images you ARE happy with

[Big V]

Good news, I have just ordered my new guide camera and they had it in stock - so they are delivering it to my brothers house in Mackay as I am visiting there for christmas. This will give me time to set it up on the new laptop and have a play with the software so that when I return to Adelaide on the 9th I will be able to get straight into it and finally produce some guided images with the 400. Merry Christmas to all!!

[surenj]

BigV, as Peter has mentioned, thanks very much for this detailed insider info into astrophotography. I knew it was hard, but this sounds impossible!!

Do you use an intervelometer for those long and multiple exposures? Obviously you must use AC power for the camera? Lastly do you need any sensor cooling apparatus?

[Big V]

No cooling, although cooling would help with noise but I am not going to modify a 6 grand camera. No need for AC power - although the power pack comes standard with the pro bodies - as the 1DMK111 gets over 6 hours out of a single battery and that equals the maximum amount of night time that you can usefully shoot in. Intervelometer, yes I do use the Canon one - a brilliant bit of equipment.

[tommyg]

Are you able to give a quick explanation of how you stack photos in Photoshop for star trails?

I've been trying to figure it out with no luck as yet

Cheers
Tom

[Alpha_7]

Virgs!

I was first blown away by your photos and appreicate you extremely high standards given your not happy with this images and look forward to seeing your shots when you really nail it! But more then the images, all the great information on your equipment, workflow and process is just a fantastic read, and great info for anyone considering this style of photography thanks for sharing your passion and expertise with us here. Just as we are lucky to have Wendell's expertise in fashion photography we are very lucky to have you sharing your work wonderful work with us in the field of astrophotography. Merry Christmas!

[Big V]

OK for stacking the photos to make star trails in Photoshop. First start with a blank canvas of the same size as your images. Then select your first image, open it, copy it, close it, paste it onto the blank canvas and for the blend mode select lighten. Repeat for as many shots as you have and bazing you now have a masterpiece that you can proudly display. If you follow the above the last thing you need to do is flatten the image, save it and close. I have given you the step by step instructions to record an action and apply it for future attempts.

Now, with all this Christmas cheer and most people being on holidays I am expecting some attempts from the forum - and remember you have to crawl before you earn to run so do not be afraid to post those early attempts and we might be able to give some helpful advice. As a starter may I suggest 400 ISO F4 5 minutes. If you do not have the ability to shoot past 30seconds, then 800 ISO. Don't worry too much about what the individual frames look like, it will be the stacked image that gives the bazing factor. Merry Christmas again to all and have fun.