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Astrophotography - Canon 300 f/4 or 800mm f/8 mirror lens
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magicaxeman
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For anything other than the moon you will need an equatorial mount of some kind unless stacking short exposures, whether that be a home made scotch mount/barn door mount, a telescope with driven equatorial mount or something like the astrotrac TT320 head.
Contrary to popular belief you don't need a fast long lens for star fields, a fast lens helps but most I used where from 28mm F2.8 to 200mm F4.
Of course for the moon the length helps, but speed isn't needed as its a surprisingly bright object.
Manual focus lenses work best in my experience as some auto focus lenses can be rather poor at manual focusing.
This is not an area where you want to use auto focus, manual really is best here.
A cable or electronic release is a must have, as is a tripod.
Live view with its magnification facility really helps for focusing.
Re the lenses the only downside to the mirror lenses is if they are poorly collimated or the fact that you are stuck at F8 or F10 all the time.
I would go for the 300mm F4, you can always use a TC if you want, but be warned the more magnification you use, the faster the moon will move through its field of view.
I'm sure John can add to this as he has more experience than me.
Contrary to popular belief you don't need a fast long lens for star fields, a fast lens helps but most I used where from 28mm F2.8 to 200mm F4.
Of course for the moon the length helps, but speed isn't needed as its a surprisingly bright object.
Manual focus lenses work best in my experience as some auto focus lenses can be rather poor at manual focusing.
This is not an area where you want to use auto focus, manual really is best here.
A cable or electronic release is a must have, as is a tripod.
Live view with its magnification facility really helps for focusing.
Re the lenses the only downside to the mirror lenses is if they are poorly collimated or the fact that you are stuck at F8 or F10 all the time.
I would go for the 300mm F4, you can always use a TC if you want, but be warned the more magnification you use, the faster the moon will move through its field of view.
I'm sure John can add to this as he has more experience than me.
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Steer clear of cheap catadioptric (mirror) lenses they give terrible results. I bought a 500mm a good few years ago and I've barely used it to be honest. It produces soft images with a pronounced cast. The 300mm even with a teleconverter is going to be a better option unless you spend lots of money.
You'd be better off buying a proper telescope (SCT or similar) with a decent drive and mount your camera at prime focus (in place of the eyepiece) if you're serious about it.
You'd be better off buying a proper telescope (SCT or similar) with a decent drive and mount your camera at prime focus (in place of the eyepiece) if you're serious about it.
As Iancandler points out, unless you want to take wide field astrophotos say 18mm fl, then you NEED to mount your camera and lens on a device which will counter the rotation of the earth (usually an equatorial mount or maybe an alt-az for short duration photos).
Unless you live in a very dark part of the UK, you will be limited by the streetlight sky glow for durations as well.
Both the 300mm f4 and the 400mm f5.6 are excellent lenses and can certainly be used to produce excellent photos on a properly aligned mount but for the cost of either of these lenses even second hand, you could buy a telescope (refractor), mount, adaptor, battery pack, anti-dew tape, timer and all the other bits you will need to take sky-at-night photographs.
Be warned, however, this hobby, like photography is addictive (and infuriating at times).
Unless you live in a very dark part of the UK, you will be limited by the streetlight sky glow for durations as well.
Both the 300mm f4 and the 400mm f5.6 are excellent lenses and can certainly be used to produce excellent photos on a properly aligned mount but for the cost of either of these lenses even second hand, you could buy a telescope (refractor), mount, adaptor, battery pack, anti-dew tape, timer and all the other bits you will need to take sky-at-night photographs.
Be warned, however, this hobby, like photography is addictive (and infuriating at times).
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If you think "normal" photography is expensive, take a look at astrophotography and see how cheap "normal" photography is.
If you want to start out with astrophotography, I'd get a cheap 80mm /f7.5 apo (i.e. reasonably well corrected) refractor. You can pick them up for around £200 and that gives you a 600mm focal length. You then need a 2" extension tube and 2"->canon or Nikon adaptor which will cost £20-£30 and you're away. You can then mount that on a sturdy tripod and take pictures of the moon.
If you want to do anything other than snapshots of the moon, you will need a motorised mount. There are two main types, alt/az (altitude/azimuth) or GEM (German Equatorial Mount). Alt/az has the problem that the sky rotates relative to the mount so you have differing amounts of rotation so you can only get short exposures. The GEM is aligned with the earths rotation so the sky just moves from left to right with it and doesn't rotate. Most people get a GEM if they are into imaging. You can then use the same telescope you used for moon snapshots to get you into constellations. Photoing the constellations is quite boring unless you are doing a wideangle and turning it into a movie to show how the sky changes over a period of time (if you want to see a most spectacular example of timelapse, take a look here: http://vimeo.com/4505537 The "cloud" rising when it is dark is the milky way...) OR if you are photographing nebula (yes, you can photo clusters, but you normally quickly move on from that!). Photoing nebula and you're starting to think about modding your cameras for better IR performance (as that's where all the interesting stuff is happening), but you can get startling results with an unmodded camera. Expect to pay £600-£1000 plus batteries/laptops etc for control for a decent mount to get to this stage. You will be taking multiple images of 90+ seconds duration and getting somewhere.
Basically, the quality of images you can get are limited by local light pollution (you can get filters to reduce) and how long you can track an object accurately. The astronomical equivalent to image stabilisation is active tracking of the mount whereby you use a second camera to track a star close to the object you're photoing. This can then correct the slight tracking errors inherent in any open-loop mechanical system. Expect to pay another £500 or so to get all the bits to do this. Now you can start to take multiple several minute exposures quite nicely and the data is starting to come out of the noise.
In all the above, you will be limited by your local conditions. It is very difficult (although not impossible) to do decent astrophotography from a big city. Once you've sorted to this stage, then it's all about better optics - and they can cost!
Another way forward is closeups of the moon or planets. Here the serious choice is a webcam (small sensor and a pain to get the target on chip I can tell you) attached to a long focal length 'scope, normally with a barlow lens which is effectively a TC (or even stacked TCs). You use a webcam as it is able to take thousands of frames and you then stack these frames to get a single image. Why do this - to combat atmospheric distortion. As the object is so bright and typically small, you need all the magnification you can get. Top lunar/planetary imagers are at the equivalent focal length of 20+metres and imaging on a 1/4 inch chip! The results are startlingly brilliant though. Here are some of my attempts at 7+metre focal lengths:
Mars:
Mars March 2010 by arad85, on Flickr
Jupiter:
Jupiter with Ganymede transition Sep 2009 by arad85, on Flickr
Saturn:
Saturn 4th March 2010 by arad85, on Flickr
Don't forget the endless hours battling equipment/the weather/dew/cold. Have I put you off yet?
If you want to start out with astrophotography, I'd get a cheap 80mm /f7.5 apo (i.e. reasonably well corrected) refractor. You can pick them up for around £200 and that gives you a 600mm focal length. You then need a 2" extension tube and 2"->canon or Nikon adaptor which will cost £20-£30 and you're away. You can then mount that on a sturdy tripod and take pictures of the moon.
If you want to do anything other than snapshots of the moon, you will need a motorised mount. There are two main types, alt/az (altitude/azimuth) or GEM (German Equatorial Mount). Alt/az has the problem that the sky rotates relative to the mount so you have differing amounts of rotation so you can only get short exposures. The GEM is aligned with the earths rotation so the sky just moves from left to right with it and doesn't rotate. Most people get a GEM if they are into imaging. You can then use the same telescope you used for moon snapshots to get you into constellations. Photoing the constellations is quite boring unless you are doing a wideangle and turning it into a movie to show how the sky changes over a period of time (if you want to see a most spectacular example of timelapse, take a look here: http://vimeo.com/4505537 The "cloud" rising when it is dark is the milky way...) OR if you are photographing nebula (yes, you can photo clusters, but you normally quickly move on from that!). Photoing nebula and you're starting to think about modding your cameras for better IR performance (as that's where all the interesting stuff is happening), but you can get startling results with an unmodded camera. Expect to pay £600-£1000 plus batteries/laptops etc for control for a decent mount to get to this stage. You will be taking multiple images of 90+ seconds duration and getting somewhere.
Basically, the quality of images you can get are limited by local light pollution (you can get filters to reduce) and how long you can track an object accurately. The astronomical equivalent to image stabilisation is active tracking of the mount whereby you use a second camera to track a star close to the object you're photoing. This can then correct the slight tracking errors inherent in any open-loop mechanical system. Expect to pay another £500 or so to get all the bits to do this. Now you can start to take multiple several minute exposures quite nicely and the data is starting to come out of the noise.
In all the above, you will be limited by your local conditions. It is very difficult (although not impossible) to do decent astrophotography from a big city. Once you've sorted to this stage, then it's all about better optics - and they can cost!
Another way forward is closeups of the moon or planets. Here the serious choice is a webcam (small sensor and a pain to get the target on chip I can tell you) attached to a long focal length 'scope, normally with a barlow lens which is effectively a TC (or even stacked TCs). You use a webcam as it is able to take thousands of frames and you then stack these frames to get a single image. Why do this - to combat atmospheric distortion. As the object is so bright and typically small, you need all the magnification you can get. Top lunar/planetary imagers are at the equivalent focal length of 20+metres and imaging on a 1/4 inch chip! The results are startlingly brilliant though. Here are some of my attempts at 7+metre focal lengths:
Mars:
Mars March 2010 by arad85, on Flickr
Jupiter:
Jupiter with Ganymede transition Sep 2009 by arad85, on Flickr
Saturn:
Saturn 4th March 2010 by arad85, on Flickr
Don't forget the endless hours battling equipment/the weather/dew/cold. Have I put you off yet?
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jgs001
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In Astrophotography... for anything other than the moon and planets... the mount is key (the mount helps a lot of you are wanting to get any scale on the planets). For the moon, it's relatively easy, with a £200 scope (as mentioned by Andy) and an SLR to get a decent result
mounted on my redsnapper
http://www.talkphotography.co.uk/forums/showthread.php?t=269766
For Deep Sky, unguidded you're looking at an average of 2 minute exposures with the basic kit, be that an Astrotrac or an HEQ5 (lighter eq mounts can be used, but they aren't as sturdy and the HEQ5 is generally considered to be the minimum)... then you add guiding, so second scope, second camera, computer control etc and if you setup correctly, you can image for 20 minutes or more (at least until the sky glow starts swamping the data). Then you can start looking at dedicated cooled Astro cameras, they start at the cost of an entry level SLR for a camera with a VGA mono sensor (then don't forget the set of LRGB filters, the filter wheel etc), and go up to well over £4000 for something with an APS-C size sensor (which will still need the filters and wheel).
Your best and first purchase should be
http://firstlightoptics.com/proddetail.php?prod=makin_every_photon_count
it'll give you an idea of the sort of things involved.
In the meantime have a look at
http://www.talkphotography.co.uk/forums/showthread.php?t=104518&highlight=basic
As to focal length, as Andy says, long focal lengths are really only needed for the moon and planets... a lot of the deep sky stuff is actually far larger than you would imagine.
One of my faves I shot with my Nifty Fifty... on top of the full guided HEQ5 setup...
So for now... I'd go with the 300mm, and work out some way to get the tracking sorted... The barndoor mount is a great idea if you're a dab hand at DIY, although you'll probably still be limited to reasonably short exposures (short is less than 2 minutes).
In respect of the mirror lens... that's basically the same design as the Maksutov type telescopes, and they do work well for Lunar/Planetary... however, it's likely the lens has been bashed, which will put the mirror collimation out... so unless you can collimate it, it's not going to produce great images. It made a big difference to my Mak (although I've still not got it right) when I collimated it.
mounted on my redsnapper
http://www.talkphotography.co.uk/forums/showthread.php?t=269766
For Deep Sky, unguidded you're looking at an average of 2 minute exposures with the basic kit, be that an Astrotrac or an HEQ5 (lighter eq mounts can be used, but they aren't as sturdy and the HEQ5 is generally considered to be the minimum)... then you add guiding, so second scope, second camera, computer control etc and if you setup correctly, you can image for 20 minutes or more (at least until the sky glow starts swamping the data). Then you can start looking at dedicated cooled Astro cameras, they start at the cost of an entry level SLR for a camera with a VGA mono sensor (then don't forget the set of LRGB filters, the filter wheel etc), and go up to well over £4000 for something with an APS-C size sensor (which will still need the filters and wheel
).Your best and first purchase should be
http://firstlightoptics.com/proddetail.php?prod=makin_every_photon_count
it'll give you an idea of the sort of things involved.
In the meantime have a look at
http://www.talkphotography.co.uk/forums/showthread.php?t=104518&highlight=basic
As to focal length, as Andy says, long focal lengths are really only needed for the moon and planets... a lot of the deep sky stuff is actually far larger than you would imagine.
One of my faves I shot with my Nifty Fifty... on top of the full guided HEQ5 setup...
So for now... I'd go with the 300mm, and work out some way to get the tracking sorted... The barndoor mount is a great idea if you're a dab hand at DIY, although you'll probably still be limited to reasonably short exposures (short is less than 2 minutes
).In respect of the mirror lens... that's basically the same design as the Maksutov type telescopes, and they do work well for Lunar/Planetary... however, it's likely the lens has been bashed, which will put the mirror collimation out... so unless you can collimate it, it's not going to produce great images. It made a big difference to my Mak (although I've still not got it right) when I collimated it.
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jgs001
Brian Cox
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Kris, you ought to be ok with the mirror lens if new... you can check collimation by putting a ball bearing as far away as possible in sunlight, centre it, focus on it, then defocus a little either side of in focus... you should be able to make out rings in the blob (the airy disk) a collimated mirror system should show equal rings all around the subject. What you will find, with the large central obstruction, is a drop in contrast. It can be corrected during processing (that's another challenge in and of itself ) though.
My scope has an identical lens to http://firstlightoptics.com/proddetail.php?prod=evostar_80ed_ds, but was bought end of line. That's the new price and is considered to be an ideal starter photography scope. It's a stunning piece of kit for the money... all my telescopic work is shot with it, and that includes images using ridiculous amounts of teleconverters inline (10x worth). Second hand they go for about £200 ish... For an idea of the images with that lens, either check out my blog, or most of my astro photos I've posted on here. You could get that scope and the HEQ5 (I use one) as a kit for up to £1000 new. Then it's all down to practice, practice, practice, and a really enormous helping of patience...
) though.My scope has an identical lens to http://firstlightoptics.com/proddetail.php?prod=evostar_80ed_ds, but was bought end of line. That's the new price and is considered to be an ideal starter photography scope. It's a stunning piece of kit for the money... all my telescopic work is shot with it, and that includes images using ridiculous amounts of teleconverters inline (10x worth). Second hand they go for about £200 ish... For an idea of the images with that lens, either check out my blog, or most of my astro photos I've posted on here. You could get that scope and the HEQ5 (I use one) as a kit for up to £1000 new. Then it's all down to practice, practice, practice, and a really enormous helping of patience
...
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I had the same 'scope as John and sold it for £180 I think. Also had the next higher mount to his as I also had a rather large 9.25" SCT (folded telescope like the cheap mirror lens) to do the planetary imaging.
The one thing about astro imaging is that it's 90% the mount, 10% the lens. People can (and do) spent many, many thousands on the mount alone (just google "paramount me" to see what £11k will get you...).
The one thing about astro imaging is that it's 90% the mount, 10% the lens. People can (and do) spent many, many thousands on the mount alone (just google "paramount me" to see what £11k will get you...).
That was my downfall... On the nights it was actually clear AND the moon wasn't up, I was finding the company indoors and a glass of wine more inviting than standing outside alone and getting coldand a really enormous helping of patience
Hi, I'm new to the forum (but have been lurking for a while). I've been having some reasonable luck with Moon shots using a 600mm APO refractor on an old EQ1 mount which is falling to bits but is still just about fit for purpose. I also used a 2x Canon teleconverter (after masking the contacts) on a Canon 550D.
Here is a recent shot taken from the back garden. The time to set up the kit and get the shot was about 7 minutes...
In addition, here is a 100% crop.
Here is a recent shot taken from the back garden. The time to set up the kit and get the shot was about 7 minutes...
In addition, here is a 100% crop.