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Old 06-12-2017, 07:12 PM
Dan05 (Daniel)
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What do I need?

Hi all,

So I have a dslr, I am about to purchase a t ring and a 2” adapter. I have a semi apo filter 2”. I’m looking at taking shots of the moon and planets. I want to make the planets as big as possible in the shots. I was reading about Barlow lenses and reducers and am now stuck as to what I should be getting.

The telescope is a bresser messier AR127L. I have a x2 Barlow for my eyepiece. But when taking photos I hear a reducer is better. Can someone explain to me in simple terms as all this is new to me.
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Old 06-12-2017, 10:01 PM
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jenchris (Jennifer)
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Oh dear. Where do I start?
A Barlow goes the opposite way to a reducer.
Ie an f7 scope will become an f14 scope with a 2x barlow.
If your dslr is an aps_c it will be 24 mm corner to corner
The focal length of your scope is xmm.
So the magnification will be x/24..times 2 for a barlow.
Planets will still be very small. The moon will be a printable size.
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Old 07-12-2017, 03:49 AM
Dan05 (Daniel)
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Ok so the point I was trying to get across is what would make planetary shots bigger? What do I need to do or have to make my photos of the planets larger?
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Old 07-12-2017, 06:45 AM
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Originally Posted by Dan05 View Post
Ok so the point I was trying to get across is what would make planetary shots bigger? What do I need to do or have to make my photos of the planets larger?
Set up closer.
Start with getting your camera on the scope and do Moon shots that will be most satisfying.
Baby steps.
Alex
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Old 07-12-2017, 07:00 AM
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doppler (Rick)
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The reducer is used for deep space objects, to get the f ratio down for long exposures. For planetary a barlow will increase the magnification for lunar and planetary images. By far the best way to capture the planets is with a video camera. You can use a dslr in video mode, some cameras will allow you to zoom in using a crop mode. The videos are then sorted and stacked in a program like registax (free online). The dslr has a large sensor so it's best to use a web type cam with a small sensor and high frame rate. https://www.bintel.com.au/product/zw...ronomy-camera/ Hopefully you have good motorised tracking mount, framing an object at high magnification is not easy. Like Alex said start with the moon.

Last edited by doppler; 07-12-2017 at 07:14 AM.
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Old 07-12-2017, 11:44 AM
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sil (Steve)
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What do I need to do or have to make my photos of the planets larger?
Others have answered this but I'd like to add maybe your expectations are all wrong about astrophotography. You don't get whole planets taking up the whole frame even on expensive setups. The example photos on brochures for telescopes can be very misleading. Before you go buying stuff expecting too much you might wnt to look for a local astronomy club night out where you can see for yourself just how small planets are when capturing. Its common for people to have unrealistic expectations with astronomy and can often waste thousands before realising what they expected is impossible.
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Old 07-12-2017, 01:49 PM
glend (Glen)
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Ok so the point I was trying to get across is what would make planetary shots bigger? What do I need to do or have to make my photos of the planets larger?
Dan, you need focal length, lots of it to make planets larger and clear. Unfortunately, ways of lengthening the focal length of your scope ( like barlows), slow down the optical 'speed' and thus you need increasingly longer exposure time to take a traditional long exposure image. You would also need a very good equatorial mount to track that planet, and you would need to guide that mount.
One popular way around this, is called lucky imaging, where you take a constant stream of video at high frame rate and then use software (like Sharpcap) to stack all those video frames. This can still require a rudimentary mount, but guiding can be avoided because high frame rate video can pile up alot of frames in 60 seconds. But for that to work you need a high frame rate video capable camera. Does your DSLR have video capability?
Suggest you search for info on "lucky imaging" to start with.

Imaging has a big learning curve, but starting with the Moon and a dslr is pretty much where everyone begins.

Certainly for the moon you should have no problems because its so bright, you can shoot short duration shots.
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Old 18-12-2017, 12:43 PM
Dan05 (Daniel)
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thank you all for the advice. I will start with the moon. start small and work up to the complicated stuff. Cheers all.
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Old 19-12-2017, 12:25 PM
Saturnine (Jeff)
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hi Daniel
Thought that I may add my 2 cents worth. For several years I used an 127 x 1200 achro on an EQ5 mount with dual axis drives for lunar and planetary imaging with a Toucam webcam and managed , on nights of steady seeing to get some acceptable images of Jupiter, Saturn, Mars and the Moon. Personally I would recommend using an webcam style video camera for what you want to do rather than a DSLR in video mode and don't cost much and there is plenty of freeware to help with capturing and processing.
As for image scale, even with the scope you have and the 2X barlow, which gives 2400mm f/ l even Jupiter at its closest,largest apparent diameter will appear on your monitor screen at about 30 / 40 mm in size.
If you have polar aligned and focused carefully and the seeing is good and the timing right you will be able to see cloud band detail and the Red Spot and shadow transits of the Galileon satellites. The rings of Saturn with the Cassini Division and some of the more prominent surface features of Mars can be captured as well.
I still use my 127mm achro occasionally for video captures when I am too lazy to get one of my better scopes set up though I have a better camera with faster frame rate now which helps beat the seeing. The achro will give some misaligned colour to the image, for me it meant that after stacking in Registax there would be a blue fringe on one side of the planetary disc and a red fringe on the other side, but this can be alleviated somewhat with the colour alignment tool in Registax. Other software like Photoshop will improve the image processing results as well. All part of the fun of learning the tricks of the trade.
So don't be afraid to use what you have and not to expect instant success
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